From 593a27c4b212e2afdf772a1f8dcb894e91bda0fa Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <khlebnikov@openvz.org>
Date: Thu, 5 Jan 2012 13:04:21 +0400
Subject: [PATCH 01/20] tty: cleanup prohibition of direct opening for unix98
 pty master

cleanup hack added in v2.6.27-3203-g15582d3

comment from that patch:

: pty: If the administrator creates a device for a ptmx slave we should not error
:
: The open path for ptmx slaves is via the ptmx device. Opening them any
: other way is not allowed. Vegard Nossum found that previously this was not
: the case and mknod foo c 128 42; cat foo would produce nasty diagnostics
:
: Signed-off-by: Alan Cox <alan@redhat.com>
: Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

devpts_get_tty() returns non-null only for inodes on devpts, but there is no
inodes for master-devices, /dev/ptmx (/dev/pts/ptmx) is the only way to open them.
Thus we can completely forbid lookup for master-devices and eliminate that hack in
tty_init_dev() because tty_open() will get EIO from tty_driver_lookup_tty().

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/tty/pty.c    |  8 +++-----
 drivers/tty/tty_io.c | 12 ++----------
 include/linux/tty.h  |  3 +--
 3 files changed, 6 insertions(+), 17 deletions(-)

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index d8653ab6f498..03147fa31d47 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -515,10 +515,8 @@ static int pty_unix98_ioctl(struct tty_struct *tty,
 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
 		struct inode *ptm_inode, int idx)
 {
-	struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
-	if (tty)
-		tty = tty->link;
-	return tty;
+	/* Master must be open via /dev/ptmx */
+	return ERR_PTR(-EIO);
 }
 
 /**
@@ -677,7 +675,7 @@ static int ptmx_open(struct inode *inode, struct file *filp)
 
 	mutex_lock(&tty_mutex);
 	tty_lock();
-	tty = tty_init_dev(ptm_driver, index, 1);
+	tty = tty_init_dev(ptm_driver, index);
 	mutex_unlock(&tty_mutex);
 
 	if (IS_ERR(tty)) {
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index e41b9bbc107d..fbcc14063804 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1365,7 +1365,6 @@ static int tty_reopen(struct tty_struct *tty)
  *	@driver: tty driver we are opening a device on
  *	@idx: device index
  *	@ret_tty: returned tty structure
- *	@first_ok: ok to open a new device (used by ptmx)
  *
  *	Prepare a tty device. This may not be a "new" clean device but
  *	could also be an active device. The pty drivers require special
@@ -1385,18 +1384,11 @@ static int tty_reopen(struct tty_struct *tty)
  * relaxed for the (most common) case of reopening a tty.
  */
 
-struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
-								int first_ok)
+struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
 {
 	struct tty_struct *tty;
 	int retval;
 
-	/* Check if pty master is being opened multiple times */
-	if (driver->subtype == PTY_TYPE_MASTER &&
-		(driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
-		return ERR_PTR(-EIO);
-	}
-
 	/*
 	 * First time open is complex, especially for PTY devices.
 	 * This code guarantees that either everything succeeds and the
@@ -1950,7 +1942,7 @@ retry_open:
 		if (retval)
 			tty = ERR_PTR(retval);
 	} else
-		tty = tty_init_dev(driver, index, 0);
+		tty = tty_init_dev(driver, index);
 
 	mutex_unlock(&tty_mutex);
 	if (driver)
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 5dbb3cb05a82..d3ebd765b548 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -480,8 +480,7 @@ extern void free_tty_struct(struct tty_struct *tty);
 extern void initialize_tty_struct(struct tty_struct *tty,
 		struct tty_driver *driver, int idx);
 extern void deinitialize_tty_struct(struct tty_struct *tty);
-extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
-								int first_ok);
+extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
 extern int tty_release(struct inode *inode, struct file *filp);
 extern int tty_init_termios(struct tty_struct *tty);
 

From a4834c102f4a46808630cad1a545cb0706b3b0a2 Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <khlebnikov@openvz.org>
Date: Thu, 5 Jan 2012 13:06:02 +0400
Subject: [PATCH 02/20] tty: move pty count limiting into devpts

Let's move this stuff to the better place, where we can account pty right in
tty-indexes managing code.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/tty/pty.c | 51 ---------------------------------------------
 fs/devpts/inode.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 52 insertions(+), 52 deletions(-)

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 03147fa31d47..d505837b3478 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -21,7 +21,6 @@
 #include <linux/major.h>
 #include <linux/mm.h>
 #include <linux/init.h>
-#include <linux/sysctl.h>
 #include <linux/device.h>
 #include <linux/uaccess.h>
 #include <linux/bitops.h>
@@ -439,55 +438,9 @@ static inline void legacy_pty_init(void) { }
 
 /* Unix98 devices */
 #ifdef CONFIG_UNIX98_PTYS
-/*
- * sysctl support for setting limits on the number of Unix98 ptys allocated.
- * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
- */
-int pty_limit = NR_UNIX98_PTY_DEFAULT;
-static int pty_limit_min;
-static int pty_limit_max = NR_UNIX98_PTY_MAX;
-static int pty_count;
 
 static struct cdev ptmx_cdev;
 
-static struct ctl_table pty_table[] = {
-	{
-		.procname	= "max",
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.data		= &pty_limit,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &pty_limit_min,
-		.extra2		= &pty_limit_max,
-	}, {
-		.procname	= "nr",
-		.maxlen		= sizeof(int),
-		.mode		= 0444,
-		.data		= &pty_count,
-		.proc_handler	= proc_dointvec,
-	}, 
-	{}
-};
-
-static struct ctl_table pty_kern_table[] = {
-	{
-		.procname	= "pty",
-		.mode		= 0555,
-		.child		= pty_table,
-	},
-	{}
-};
-
-static struct ctl_table pty_root_table[] = {
-	{
-		.procname	= "kernel",
-		.mode		= 0555,
-		.child		= pty_kern_table,
-	},
-	{}
-};
-
-
 static int pty_unix98_ioctl(struct tty_struct *tty,
 			    unsigned int cmd, unsigned long arg)
 {
@@ -587,7 +540,6 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
 	 */
 	tty_driver_kref_get(driver);
 	tty->count++;
-	pty_count++;
 	return 0;
 err_free_mem:
 	deinitialize_tty_struct(o_tty);
@@ -601,7 +553,6 @@ err_free_tty:
 
 static void ptm_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 {
-	pty_count--;
 }
 
 static void pts_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
@@ -760,8 +711,6 @@ static void __init unix98_pty_init(void)
 	if (tty_register_driver(pts_driver))
 		panic("Couldn't register Unix98 pts driver");
 
-	register_sysctl_table(pty_root_table);
-
 	/* Now create the /dev/ptmx special device */
 	tty_default_fops(&ptmx_fops);
 	ptmx_fops.open = ptmx_open;
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index c4e2a58a2e82..c2c7317d5687 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -36,7 +36,52 @@
 #define DEVPTS_DEFAULT_PTMX_MODE 0000
 #define PTMX_MINOR	2
 
-extern int pty_limit;			/* Config limit on Unix98 ptys */
+/*
+ * sysctl support for setting limits on the number of Unix98 ptys allocated.
+ * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
+ */
+static int pty_limit = NR_UNIX98_PTY_DEFAULT;
+static int pty_limit_min;
+static int pty_limit_max = NR_UNIX98_PTY_MAX;
+static int pty_count;
+
+static struct ctl_table pty_table[] = {
+	{
+		.procname	= "max",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.data		= &pty_limit,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &pty_limit_min,
+		.extra2		= &pty_limit_max,
+	}, {
+		.procname	= "nr",
+		.maxlen		= sizeof(int),
+		.mode		= 0444,
+		.data		= &pty_count,
+		.proc_handler	= proc_dointvec,
+	},
+	{}
+};
+
+static struct ctl_table pty_kern_table[] = {
+	{
+		.procname	= "pty",
+		.mode		= 0555,
+		.child		= pty_table,
+	},
+	{}
+};
+
+static struct ctl_table pty_root_table[] = {
+	{
+		.procname	= "kernel",
+		.mode		= 0555,
+		.child		= pty_kern_table,
+	},
+	{}
+};
+
 static DEFINE_MUTEX(allocated_ptys_lock);
 
 static struct vfsmount *devpts_mnt;
@@ -451,6 +496,7 @@ retry:
 		mutex_unlock(&allocated_ptys_lock);
 		return -EIO;
 	}
+	pty_count++;
 	mutex_unlock(&allocated_ptys_lock);
 	return index;
 }
@@ -462,6 +508,7 @@ void devpts_kill_index(struct inode *ptmx_inode, int idx)
 
 	mutex_lock(&allocated_ptys_lock);
 	ida_remove(&fsi->allocated_ptys, idx);
+	pty_count--;
 	mutex_unlock(&allocated_ptys_lock);
 }
 
@@ -558,11 +605,15 @@ void devpts_pty_kill(struct tty_struct *tty)
 static int __init init_devpts_fs(void)
 {
 	int err = register_filesystem(&devpts_fs_type);
+	struct ctl_table_header *table;
+
 	if (!err) {
+		table = register_sysctl_table(pty_root_table);
 		devpts_mnt = kern_mount(&devpts_fs_type);
 		if (IS_ERR(devpts_mnt)) {
 			err = PTR_ERR(devpts_mnt);
 			unregister_filesystem(&devpts_fs_type);
+			unregister_sysctl_table(table);
 		}
 	}
 	return err;

From e9aba5158a80098447ff207a452a3418ae7ee386 Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <khlebnikov@openvz.org>
Date: Thu, 5 Jan 2012 13:06:11 +0400
Subject: [PATCH 03/20] tty: rework pty count limiting

After adding devpts multiple-insrances sysctl kernel.pty.max limit pty count for
each devpts instance independently, while kernel.pty.nr shows total pty count.

This patch restores sysctl kernel.pty.max as global limit (4096 by default),
adds pty reseve for main devpts (mounted without "newinstance" argument),
and new sysctl to tune it: kernel.pty.reserve (1024 by default)

Also it adds devpts mount option "max=%d" to limit pty count for each devpts
instance independently. (by default NR_UNIX98_PTY_MAX == 2^20)

Thus devpts instances in containers cannot eat up all available pty even if we didn't
set any limits, while with "max" argument we can adjust limits more precisely.

Plus, now open("/dev/ptmx") return -ENOSPC in case lack of pty indexes,
this is more informative than -EIO.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 fs/devpts/inode.c   | 34 ++++++++++++++++++++++++++++++----
 include/linux/tty.h |  1 +
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index c2c7317d5687..1c6f908e38ca 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -41,8 +41,9 @@
  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
  */
 static int pty_limit = NR_UNIX98_PTY_DEFAULT;
+static int pty_reserve = NR_UNIX98_PTY_RESERVE;
 static int pty_limit_min;
-static int pty_limit_max = NR_UNIX98_PTY_MAX;
+static int pty_limit_max = INT_MAX;
 static int pty_count;
 
 static struct ctl_table pty_table[] = {
@@ -54,6 +55,14 @@ static struct ctl_table pty_table[] = {
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= &pty_limit_min,
 		.extra2		= &pty_limit_max,
+	}, {
+		.procname	= "reserve",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.data		= &pty_reserve,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &pty_limit_min,
+		.extra2		= &pty_limit_max,
 	}, {
 		.procname	= "nr",
 		.maxlen		= sizeof(int),
@@ -94,10 +103,11 @@ struct pts_mount_opts {
 	umode_t mode;
 	umode_t ptmxmode;
 	int newinstance;
+	int max;
 };
 
 enum {
-	Opt_uid, Opt_gid, Opt_mode, Opt_ptmxmode, Opt_newinstance,
+	Opt_uid, Opt_gid, Opt_mode, Opt_ptmxmode, Opt_newinstance,  Opt_max,
 	Opt_err
 };
 
@@ -108,6 +118,7 @@ static const match_table_t tokens = {
 #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
 	{Opt_ptmxmode, "ptmxmode=%o"},
 	{Opt_newinstance, "newinstance"},
+	{Opt_max, "max=%d"},
 #endif
 	{Opt_err, NULL}
 };
@@ -154,6 +165,7 @@ static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)
 	opts->gid     = 0;
 	opts->mode    = DEVPTS_DEFAULT_MODE;
 	opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
+	opts->max     = NR_UNIX98_PTY_MAX;
 
 	/* newinstance makes sense only on initial mount */
 	if (op == PARSE_MOUNT)
@@ -197,6 +209,12 @@ static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)
 			if (op == PARSE_MOUNT)
 				opts->newinstance = 1;
 			break;
+		case Opt_max:
+			if (match_int(&args[0], &option) ||
+			    option < 0 || option > NR_UNIX98_PTY_MAX)
+				return -EINVAL;
+			opts->max = option;
+			break;
 #endif
 		default:
 			printk(KERN_ERR "devpts: called with bogus options\n");
@@ -303,6 +321,8 @@ static int devpts_show_options(struct seq_file *seq, struct dentry *root)
 	seq_printf(seq, ",mode=%03o", opts->mode);
 #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
 	seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode);
+	if (opts->max < NR_UNIX98_PTY_MAX)
+		seq_printf(seq, ",max=%d", opts->max);
 #endif
 
 	return 0;
@@ -483,6 +503,12 @@ retry:
 		return -ENOMEM;
 
 	mutex_lock(&allocated_ptys_lock);
+	if (pty_count >= pty_limit -
+			(fsi->mount_opts.newinstance ? pty_reserve : 0)) {
+		mutex_unlock(&allocated_ptys_lock);
+		return -ENOSPC;
+	}
+
 	ida_ret = ida_get_new(&fsi->allocated_ptys, &index);
 	if (ida_ret < 0) {
 		mutex_unlock(&allocated_ptys_lock);
@@ -491,10 +517,10 @@ retry:
 		return -EIO;
 	}
 
-	if (index >= pty_limit) {
+	if (index >= fsi->mount_opts.max) {
 		ida_remove(&fsi->allocated_ptys, index);
 		mutex_unlock(&allocated_ptys_lock);
-		return -EIO;
+		return -ENOSPC;
 	}
 	pty_count++;
 	mutex_unlock(&allocated_ptys_lock);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index d3ebd765b548..d40774188203 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -52,6 +52,7 @@
  * hardcoded at present.)
  */
 #define NR_UNIX98_PTY_DEFAULT	4096      /* Default maximum for Unix98 ptys */
+#define NR_UNIX98_PTY_RESERVE	1024	  /* Default reserve for main devpts */
 #define NR_UNIX98_PTY_MAX	(1 << MINORBITS) /* Absolute limit */
 
 /*

From 3afbd89c9639c344300dcdd7d4e5e18dda559fd4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
Date: Wed, 25 Jan 2012 09:05:04 +0100
Subject: [PATCH 04/20] serial/efm32: add new driver
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 .../bindings/tty/serial/efm32-uart.txt        |  14 +
 drivers/tty/serial/Kconfig                    |  13 +
 drivers/tty/serial/Makefile                   |   1 +
 drivers/tty/serial/efm32-uart.c               | 830 ++++++++++++++++++
 include/linux/platform_data/efm32-uart.h      |  18 +
 include/linux/serial_core.h                   |   2 +
 6 files changed, 878 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/tty/serial/efm32-uart.txt
 create mode 100644 drivers/tty/serial/efm32-uart.c
 create mode 100644 include/linux/platform_data/efm32-uart.h

diff --git a/Documentation/devicetree/bindings/tty/serial/efm32-uart.txt b/Documentation/devicetree/bindings/tty/serial/efm32-uart.txt
new file mode 100644
index 000000000000..6588b6950a7f
--- /dev/null
+++ b/Documentation/devicetree/bindings/tty/serial/efm32-uart.txt
@@ -0,0 +1,14 @@
+* Energymicro efm32 UART
+
+Required properties:
+- compatible : Should be "efm32,uart"
+- reg : Address and length of the register set
+- interrupts : Should contain uart interrupt
+
+Example:
+
+uart@0x4000c400 {
+	compatible = "efm32,uart";
+	reg = <0x4000c400 0x400>;
+	interrupts = <15>;
+};
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index aca2386c5ef1..6e24a8f5fd2a 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1628,4 +1628,17 @@ config SERIAL_AR933X_NR_UARTS
 	  Set this to the number of serial ports you want the driver
 	  to support.
 
+config SERIAL_EFM32_UART
+	tristate "EFM32 UART/USART port."
+	depends on ARCH_EFM32
+	select SERIAL_CORE
+	help
+	  This driver support the USART and UART ports on
+	  Energy Micro's efm32 SoCs.
+
+config SERIAL_EFM32_UART_CONSOLE
+	bool "EFM32 UART/USART console support"
+	depends on SERIAL_EFM32_UART=y
+	select SERIAL_CORE_CONSOLE
+
 endmenu
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index f5b01f2ce525..1997ad4a39a6 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -92,3 +92,4 @@ obj-$(CONFIG_SERIAL_LANTIQ)	+= lantiq.o
 obj-$(CONFIG_SERIAL_XILINX_PS_UART) += xilinx_uartps.o
 obj-$(CONFIG_SERIAL_SIRFSOC) += sirfsoc_uart.o
 obj-$(CONFIG_SERIAL_AR933X)   += ar933x_uart.o
+obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o
diff --git a/drivers/tty/serial/efm32-uart.c b/drivers/tty/serial/efm32-uart.c
new file mode 100644
index 000000000000..615e46470491
--- /dev/null
+++ b/drivers/tty/serial/efm32-uart.c
@@ -0,0 +1,830 @@
+#if defined(CONFIG_SERIAL_EFM32_UART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/serial_core.h>
+#include <linux/tty_flip.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#include <linux/platform_data/efm32-uart.h>
+
+#define DRIVER_NAME "efm32-uart"
+#define DEV_NAME "ttyefm"
+
+#define UARTn_CTRL		0x00
+#define UARTn_CTRL_SYNC		0x0001
+#define UARTn_CTRL_TXBIL		0x1000
+
+#define UARTn_FRAME		0x04
+#define UARTn_FRAME_DATABITS__MASK	0x000f
+#define UARTn_FRAME_DATABITS(n)		((n) - 3)
+#define UARTn_FRAME_PARITY_NONE		0x0000
+#define UARTn_FRAME_PARITY_EVEN		0x0200
+#define UARTn_FRAME_PARITY_ODD		0x0300
+#define UARTn_FRAME_STOPBITS_HALF	0x0000
+#define UARTn_FRAME_STOPBITS_ONE	0x1000
+#define UARTn_FRAME_STOPBITS_TWO	0x3000
+
+#define UARTn_CMD		0x0c
+#define UARTn_CMD_RXEN			0x0001
+#define UARTn_CMD_RXDIS		0x0002
+#define UARTn_CMD_TXEN			0x0004
+#define UARTn_CMD_TXDIS		0x0008
+
+#define UARTn_STATUS		0x10
+#define UARTn_STATUS_TXENS		0x0002
+#define UARTn_STATUS_TXC		0x0020
+#define UARTn_STATUS_TXBL		0x0040
+#define UARTn_STATUS_RXDATAV		0x0080
+
+#define UARTn_CLKDIV		0x14
+
+#define UARTn_RXDATAX		0x18
+#define UARTn_RXDATAX_RXDATA__MASK	0x01ff
+#define UARTn_RXDATAX_PERR		0x4000
+#define UARTn_RXDATAX_FERR		0x8000
+/*
+ * This is a software only flag used for ignore_status_mask and
+ * read_status_mask! It's used for breaks that the hardware doesn't report
+ * explicitly.
+ */
+#define SW_UARTn_RXDATAX_BERR		0x2000
+
+#define UARTn_TXDATA		0x34
+
+#define UARTn_IF		0x40
+#define UARTn_IF_TXC			0x0001
+#define UARTn_IF_TXBL			0x0002
+#define UARTn_IF_RXDATAV		0x0004
+#define UARTn_IF_RXOF			0x0010
+
+#define UARTn_IFS		0x44
+#define UARTn_IFC		0x48
+#define UARTn_IEN		0x4c
+
+#define UARTn_ROUTE		0x54
+#define UARTn_ROUTE_LOCATION__MASK	0x0700
+#define UARTn_ROUTE_LOCATION(n)		(((n) << 8) & UARTn_ROUTE_LOCATION__MASK)
+#define UARTn_ROUTE_RXPEN		0x0001
+#define UARTn_ROUTE_TXPEN		0x0002
+
+struct efm32_uart_port {
+	struct uart_port port;
+	unsigned int txirq;
+	struct clk *clk;
+};
+#define to_efm_port(_port) container_of(_port, struct efm32_uart_port, port)
+#define efm_debug(efm_port, format, arg...)			\
+	dev_dbg(efm_port->port.dev, format, ##arg)
+
+static void efm32_uart_write32(struct efm32_uart_port *efm_port,
+		u32 value, unsigned offset)
+{
+	writel_relaxed(value, efm_port->port.membase + offset);
+}
+
+static u32 efm32_uart_read32(struct efm32_uart_port *efm_port,
+		unsigned offset)
+{
+	return readl_relaxed(efm_port->port.membase + offset);
+}
+
+static unsigned int efm32_uart_tx_empty(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	u32 status = efm32_uart_read32(efm_port, UARTn_STATUS);
+
+	if (status & UARTn_STATUS_TXC)
+		return TIOCSER_TEMT;
+	else
+		return 0;
+}
+
+static void efm32_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	/* sorry, neither handshaking lines nor loop functionallity */
+}
+
+static unsigned int efm32_uart_get_mctrl(struct uart_port *port)
+{
+	/* sorry, no handshaking lines available */
+	return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR;
+}
+
+static void efm32_uart_stop_tx(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	u32 ien = efm32_uart_read32(efm_port,  UARTn_IEN);
+
+	efm32_uart_write32(efm_port, UARTn_CMD_TXDIS, UARTn_CMD);
+	ien &= ~(UARTn_IF_TXC | UARTn_IF_TXBL);
+	efm32_uart_write32(efm_port, ien, UARTn_IEN);
+}
+
+static void efm32_uart_tx_chars(struct efm32_uart_port *efm_port)
+{
+	struct uart_port *port = &efm_port->port;
+	struct circ_buf *xmit = &port->state->xmit;
+
+	while (efm32_uart_read32(efm_port, UARTn_STATUS) &
+			UARTn_STATUS_TXBL) {
+		if (port->x_char) {
+			port->icount.tx++;
+			efm32_uart_write32(efm_port, port->x_char,
+					UARTn_TXDATA);
+			port->x_char = 0;
+			continue;
+		}
+		if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
+			port->icount.tx++;
+			efm32_uart_write32(efm_port, xmit->buf[xmit->tail],
+					UARTn_TXDATA);
+			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		} else
+			break;
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	if (!port->x_char && uart_circ_empty(xmit) &&
+			efm32_uart_read32(efm_port, UARTn_STATUS) &
+				UARTn_STATUS_TXC)
+		efm32_uart_stop_tx(port);
+}
+
+static void efm32_uart_start_tx(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	u32 ien;
+
+	efm32_uart_write32(efm_port,
+			UARTn_IF_TXBL | UARTn_IF_TXC, UARTn_IFC);
+	ien = efm32_uart_read32(efm_port, UARTn_IEN);
+	efm32_uart_write32(efm_port,
+			ien | UARTn_IF_TXBL | UARTn_IF_TXC, UARTn_IEN);
+	efm32_uart_write32(efm_port, UARTn_CMD_TXEN, UARTn_CMD);
+
+	efm32_uart_tx_chars(efm_port);
+}
+
+static void efm32_uart_stop_rx(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+
+	efm32_uart_write32(efm_port, UARTn_CMD_RXDIS, UARTn_CMD);
+}
+
+static void efm32_uart_enable_ms(struct uart_port *port)
+{
+	/* no handshake lines, no modem status interrupts */
+}
+
+static void efm32_uart_break_ctl(struct uart_port *port, int ctl)
+{
+	/* not possible without fiddling with gpios */
+}
+
+static void efm32_uart_rx_chars(struct efm32_uart_port *efm_port,
+		struct tty_struct *tty)
+{
+	struct uart_port *port = &efm_port->port;
+
+	while (efm32_uart_read32(efm_port, UARTn_STATUS) &
+			UARTn_STATUS_RXDATAV) {
+		u32 rxdata = efm32_uart_read32(efm_port, UARTn_RXDATAX);
+		int flag = 0;
+
+		/*
+		 * This is a reserved bit and I only saw it read as 0. But to be
+		 * sure not to be confused too much by new devices adhere to the
+		 * warning in the reference manual that reserverd bits might
+		 * read as 1 in the future.
+		 */
+		rxdata &= ~SW_UARTn_RXDATAX_BERR;
+
+		port->icount.rx++;
+
+		if ((rxdata & UARTn_RXDATAX_FERR) &&
+				!(rxdata & UARTn_RXDATAX_RXDATA__MASK)) {
+			rxdata |= SW_UARTn_RXDATAX_BERR;
+			port->icount.brk++;
+			if (uart_handle_break(port))
+				continue;
+		} else if (rxdata & UARTn_RXDATAX_PERR)
+			port->icount.parity++;
+		else if (rxdata & UARTn_RXDATAX_FERR)
+			port->icount.frame++;
+
+		rxdata &= port->read_status_mask;
+
+		if (rxdata & SW_UARTn_RXDATAX_BERR)
+			flag = TTY_BREAK;
+		else if (rxdata & UARTn_RXDATAX_PERR)
+			flag = TTY_PARITY;
+		else if (rxdata & UARTn_RXDATAX_FERR)
+			flag = TTY_FRAME;
+		else if (uart_handle_sysrq_char(port,
+					rxdata & UARTn_RXDATAX_RXDATA__MASK))
+			continue;
+
+		if (tty && (rxdata & port->ignore_status_mask) == 0)
+			tty_insert_flip_char(tty,
+					rxdata & UARTn_RXDATAX_RXDATA__MASK, flag);
+	}
+}
+
+static irqreturn_t efm32_uart_rxirq(int irq, void *data)
+{
+	struct efm32_uart_port *efm_port = data;
+	u32 irqflag = efm32_uart_read32(efm_port, UARTn_IF);
+	int handled = IRQ_NONE;
+	struct uart_port *port = &efm_port->port;
+	struct tty_struct *tty;
+
+	spin_lock(&port->lock);
+
+	tty = tty_kref_get(port->state->port.tty);
+
+	if (irqflag & UARTn_IF_RXDATAV) {
+		efm32_uart_write32(efm_port, UARTn_IF_RXDATAV, UARTn_IFC);
+		efm32_uart_rx_chars(efm_port, tty);
+
+		handled = IRQ_HANDLED;
+	}
+
+	if (irqflag & UARTn_IF_RXOF) {
+		efm32_uart_write32(efm_port, UARTn_IF_RXOF, UARTn_IFC);
+		port->icount.overrun++;
+		if (tty)
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+
+		handled = IRQ_HANDLED;
+	}
+
+	if (tty) {
+		tty_flip_buffer_push(tty);
+		tty_kref_put(tty);
+	}
+
+	spin_unlock(&port->lock);
+
+	return handled;
+}
+
+static irqreturn_t efm32_uart_txirq(int irq, void *data)
+{
+	struct efm32_uart_port *efm_port = data;
+	u32 irqflag = efm32_uart_read32(efm_port, UARTn_IF);
+
+	/* TXBL doesn't need to be cleared */
+	if (irqflag & UARTn_IF_TXC)
+		efm32_uart_write32(efm_port, UARTn_IF_TXC, UARTn_IFC);
+
+	if (irqflag & (UARTn_IF_TXC | UARTn_IF_TXBL)) {
+		efm32_uart_tx_chars(efm_port);
+		return IRQ_HANDLED;
+	} else
+		return IRQ_NONE;
+}
+
+static int efm32_uart_startup(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	u32 location = 0;
+	struct efm32_uart_pdata *pdata = dev_get_platdata(port->dev);
+	int ret;
+
+	if (pdata)
+		location = UARTn_ROUTE_LOCATION(pdata->location);
+
+	ret = clk_enable(efm_port->clk);
+	if (ret) {
+		efm_debug(efm_port, "failed to enable clk\n");
+		goto err_clk_enable;
+	}
+	port->uartclk = clk_get_rate(efm_port->clk);
+
+	/* Enable pins at configured location */
+	efm32_uart_write32(efm_port, location | UARTn_ROUTE_RXPEN | UARTn_ROUTE_TXPEN,
+			UARTn_ROUTE);
+
+	ret = request_irq(port->irq, efm32_uart_rxirq, 0,
+			DRIVER_NAME, efm_port);
+	if (ret) {
+		efm_debug(efm_port, "failed to register rxirq\n");
+		goto err_request_irq_rx;
+	}
+
+	/* disable all irqs */
+	efm32_uart_write32(efm_port, 0, UARTn_IEN);
+
+	ret = request_irq(efm_port->txirq, efm32_uart_txirq, 0,
+			DRIVER_NAME, efm_port);
+	if (ret) {
+		efm_debug(efm_port, "failed to register txirq\n");
+		free_irq(port->irq, efm_port);
+err_request_irq_rx:
+
+		clk_disable(efm_port->clk);
+	} else {
+		efm32_uart_write32(efm_port,
+				UARTn_IF_RXDATAV | UARTn_IF_RXOF, UARTn_IEN);
+		efm32_uart_write32(efm_port, UARTn_CMD_RXEN, UARTn_CMD);
+	}
+
+err_clk_enable:
+	return ret;
+}
+
+static void efm32_uart_shutdown(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+
+	efm32_uart_write32(efm_port, 0, UARTn_IEN);
+	free_irq(port->irq, efm_port);
+
+	clk_disable(efm_port->clk);
+}
+
+static void efm32_uart_set_termios(struct uart_port *port,
+		struct ktermios *new, struct ktermios *old)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	unsigned long flags;
+	unsigned baud;
+	u32 clkdiv;
+	u32 frame = 0;
+
+	/* no modem control lines */
+	new->c_cflag &= ~(CRTSCTS | CMSPAR);
+
+	baud = uart_get_baud_rate(port, new, old,
+			DIV_ROUND_CLOSEST(port->uartclk, 16 * 8192),
+			DIV_ROUND_CLOSEST(port->uartclk, 16));
+
+	switch (new->c_cflag & CSIZE) {
+	case CS5:
+		frame |= UARTn_FRAME_DATABITS(5);
+		break;
+	case CS6:
+		frame |= UARTn_FRAME_DATABITS(6);
+		break;
+	case CS7:
+		frame |= UARTn_FRAME_DATABITS(7);
+		break;
+	case CS8:
+		frame |= UARTn_FRAME_DATABITS(8);
+		break;
+	}
+
+	if (new->c_cflag & CSTOPB)
+		/* the receiver only verifies the first stop bit */
+		frame |= UARTn_FRAME_STOPBITS_TWO;
+	else
+		frame |= UARTn_FRAME_STOPBITS_ONE;
+
+	if (new->c_cflag & PARENB) {
+		if (new->c_cflag & PARODD)
+			frame |= UARTn_FRAME_PARITY_ODD;
+		else
+			frame |= UARTn_FRAME_PARITY_EVEN;
+	} else
+		frame |= UARTn_FRAME_PARITY_NONE;
+
+	/*
+	 * the 6 lowest bits of CLKDIV are dc, bit 6 has value 0.25.
+	 * port->uartclk <= 14e6, so 4 * port->uartclk doesn't overflow.
+	 */
+	clkdiv = (DIV_ROUND_CLOSEST(4 * port->uartclk, 16 * baud) - 4) << 6;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	efm32_uart_write32(efm_port,
+			UARTn_CMD_TXDIS | UARTn_CMD_RXDIS, UARTn_CMD);
+
+	port->read_status_mask = UARTn_RXDATAX_RXDATA__MASK;
+	if (new->c_iflag & INPCK)
+		port->read_status_mask |=
+			UARTn_RXDATAX_FERR | UARTn_RXDATAX_PERR;
+	if (new->c_iflag & (BRKINT | PARMRK))
+		port->read_status_mask |= SW_UARTn_RXDATAX_BERR;
+
+	port->ignore_status_mask = 0;
+	if (new->c_iflag & IGNPAR)
+		port->ignore_status_mask |=
+			UARTn_RXDATAX_FERR | UARTn_RXDATAX_PERR;
+	if (new->c_iflag & IGNBRK)
+		port->ignore_status_mask |= SW_UARTn_RXDATAX_BERR;
+
+	uart_update_timeout(port, new->c_cflag, baud);
+
+	efm32_uart_write32(efm_port, UARTn_CTRL_TXBIL, UARTn_CTRL);
+	efm32_uart_write32(efm_port, frame, UARTn_FRAME);
+	efm32_uart_write32(efm_port, clkdiv, UARTn_CLKDIV);
+
+	efm32_uart_write32(efm_port, UARTn_CMD_TXEN | UARTn_CMD_RXEN,
+			UARTn_CMD);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *efm32_uart_type(struct uart_port *port)
+{
+	return port->type == PORT_EFMUART ? "efm32-uart" : NULL;
+}
+
+static void efm32_uart_release_port(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+
+	clk_unprepare(efm_port->clk);
+	clk_put(efm_port->clk);
+	iounmap(port->membase);
+}
+
+static int efm32_uart_request_port(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	int ret;
+
+	port->membase = ioremap(port->mapbase, 60);
+	if (!efm_port->port.membase) {
+		ret = -ENOMEM;
+		efm_debug(efm_port, "failed to remap\n");
+		goto err_ioremap;
+	}
+
+	efm_port->clk = clk_get(port->dev, NULL);
+	if (IS_ERR(efm_port->clk)) {
+		ret = PTR_ERR(efm_port->clk);
+		efm_debug(efm_port, "failed to get clock\n");
+		goto err_clk_get;
+	}
+
+	ret = clk_prepare(efm_port->clk);
+	if (ret) {
+		clk_put(efm_port->clk);
+err_clk_get:
+
+		iounmap(port->membase);
+err_ioremap:
+		return ret;
+	}
+	return 0;
+}
+
+static void efm32_uart_config_port(struct uart_port *port, int type)
+{
+	if (type & UART_CONFIG_TYPE &&
+			!efm32_uart_request_port(port))
+		port->type = PORT_EFMUART;
+}
+
+static int efm32_uart_verify_port(struct uart_port *port,
+		struct serial_struct *serinfo)
+{
+	int ret = 0;
+
+	if (serinfo->type != PORT_UNKNOWN && serinfo->type != PORT_EFMUART)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+static struct uart_ops efm32_uart_pops = {
+	.tx_empty = efm32_uart_tx_empty,
+	.set_mctrl = efm32_uart_set_mctrl,
+	.get_mctrl = efm32_uart_get_mctrl,
+	.stop_tx = efm32_uart_stop_tx,
+	.start_tx = efm32_uart_start_tx,
+	.stop_rx = efm32_uart_stop_rx,
+	.enable_ms = efm32_uart_enable_ms,
+	.break_ctl = efm32_uart_break_ctl,
+	.startup = efm32_uart_startup,
+	.shutdown = efm32_uart_shutdown,
+	.set_termios = efm32_uart_set_termios,
+	.type = efm32_uart_type,
+	.release_port = efm32_uart_release_port,
+	.request_port = efm32_uart_request_port,
+	.config_port = efm32_uart_config_port,
+	.verify_port = efm32_uart_verify_port,
+};
+
+static struct efm32_uart_port *efm32_uart_ports[5];
+
+#ifdef CONFIG_SERIAL_EFM32_UART_CONSOLE
+static void efm32_uart_console_putchar(struct uart_port *port, int ch)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	unsigned int timeout = 0x400;
+	u32 status;
+
+	while (1) {
+		status = efm32_uart_read32(efm_port, UARTn_STATUS);
+
+		if (status & UARTn_STATUS_TXBL)
+			break;
+		if (!timeout--)
+			return;
+	}
+	efm32_uart_write32(efm_port, ch, UARTn_TXDATA);
+}
+
+static void efm32_uart_console_write(struct console *co, const char *s,
+		unsigned int count)
+{
+	struct efm32_uart_port *efm_port = efm32_uart_ports[co->index];
+	u32 status = efm32_uart_read32(efm_port, UARTn_STATUS);
+	unsigned int timeout = 0x400;
+
+	if (!(status & UARTn_STATUS_TXENS))
+		efm32_uart_write32(efm_port, UARTn_CMD_TXEN, UARTn_CMD);
+
+	uart_console_write(&efm_port->port, s, count,
+			efm32_uart_console_putchar);
+
+	/* Wait for the transmitter to become empty */
+	while (1) {
+		u32 status = efm32_uart_read32(efm_port, UARTn_STATUS);
+		if (status & UARTn_STATUS_TXC)
+			break;
+		if (!timeout--)
+			break;
+	}
+
+	if (!(status & UARTn_STATUS_TXENS))
+		efm32_uart_write32(efm_port, UARTn_CMD_TXDIS, UARTn_CMD);
+}
+
+static void efm32_uart_console_get_options(struct efm32_uart_port *efm_port,
+		int *baud, int *parity, int *bits)
+{
+	u32 ctrl = efm32_uart_read32(efm_port, UARTn_CTRL);
+	u32 route, clkdiv, frame;
+
+	if (ctrl & UARTn_CTRL_SYNC)
+		/* not operating in async mode */
+		return;
+
+	route = efm32_uart_read32(efm_port, UARTn_ROUTE);
+	if (!(route & UARTn_ROUTE_TXPEN))
+		/* tx pin not routed */
+		return;
+
+	clkdiv = efm32_uart_read32(efm_port, UARTn_CLKDIV);
+
+	*baud = DIV_ROUND_CLOSEST(4 * efm_port->port.uartclk,
+			16 * (4 + (clkdiv >> 6)));
+
+	frame = efm32_uart_read32(efm_port, UARTn_FRAME);
+	if (frame & UARTn_FRAME_PARITY_ODD)
+		*parity = 'o';
+	else if (frame & UARTn_FRAME_PARITY_EVEN)
+		*parity = 'e';
+	else
+		*parity = 'n';
+
+	*bits = (frame & UARTn_FRAME_DATABITS__MASK) -
+			UARTn_FRAME_DATABITS(4) + 4;
+
+	efm_debug(efm_port, "get_opts: options=%d%c%d\n",
+			*baud, *parity, *bits);
+}
+
+static int efm32_uart_console_setup(struct console *co, char *options)
+{
+	struct efm32_uart_port *efm_port;
+	int baud = 115200;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+	int ret;
+
+	if (co->index < 0 || co->index >= ARRAY_SIZE(efm32_uart_ports)) {
+		unsigned i;
+		for (i = 0; i < ARRAY_SIZE(efm32_uart_ports); ++i) {
+			if (efm32_uart_ports[i]) {
+				pr_warn("efm32-console: fall back to console index %u (from %hhi)\n",
+						i, co->index);
+				co->index = i;
+				break;
+			}
+		}
+	}
+
+	efm_port = efm32_uart_ports[co->index];
+	if (!efm_port) {
+		pr_warn("efm32-console: No port at %d\n", co->index);
+		return -ENODEV;
+	}
+
+	ret = clk_prepare(efm_port->clk);
+	if (ret) {
+		dev_warn(efm_port->port.dev,
+				"console: clk_prepare failed: %d\n", ret);
+		return ret;
+	}
+
+	efm_port->port.uartclk = clk_get_rate(efm_port->clk);
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+	else
+		efm32_uart_console_get_options(efm_port,
+				&baud, &parity, &bits);
+
+	return uart_set_options(&efm_port->port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver efm32_uart_reg;
+
+static struct console efm32_uart_console = {
+	.name = DEV_NAME,
+	.write = efm32_uart_console_write,
+	.device = uart_console_device,
+	.setup = efm32_uart_console_setup,
+	.flags = CON_PRINTBUFFER,
+	.index = -1,
+	.data = &efm32_uart_reg,
+};
+
+#else
+#define efm32_uart_console (*(struct console *)NULL)
+#endif /* ifdef CONFIG_SERIAL_EFM32_UART_CONSOLE / else */
+
+static struct uart_driver efm32_uart_reg = {
+	.owner = THIS_MODULE,
+	.driver_name = DRIVER_NAME,
+	.dev_name = DEV_NAME,
+	.nr = ARRAY_SIZE(efm32_uart_ports),
+	.cons = &efm32_uart_console,
+};
+
+static int efm32_uart_probe_dt(struct platform_device *pdev,
+		struct efm32_uart_port *efm_port)
+{
+	struct device_node *np = pdev->dev.of_node;
+	int ret;
+
+	if (!np)
+		return 1;
+
+	ret = of_alias_get_id(np, "serial");
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to get alias id: %d\n", ret);
+		return ret;
+	} else {
+		efm_port->port.line = ret;
+		return 0;
+	}
+
+}
+
+static int __devinit efm32_uart_probe(struct platform_device *pdev)
+{
+	struct efm32_uart_port *efm_port;
+	struct resource *res;
+	int ret;
+
+	efm_port = kzalloc(sizeof(*efm_port), GFP_KERNEL);
+	if (!efm_port) {
+		dev_dbg(&pdev->dev, "failed to allocate private data\n");
+		return -ENOMEM;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENODEV;
+		dev_dbg(&pdev->dev, "failed to determine base address\n");
+		goto err_get_base;
+	}
+
+	if (resource_size(res) < 60) {
+		ret = -EINVAL;
+		dev_dbg(&pdev->dev, "memory resource too small\n");
+		goto err_too_small;
+	}
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret <= 0) {
+		dev_dbg(&pdev->dev, "failed to get rx irq\n");
+		goto err_get_rxirq;
+	}
+
+	efm_port->port.irq = ret;
+
+	ret = platform_get_irq(pdev, 1);
+	if (ret <= 0)
+		ret = efm_port->port.irq + 1;
+
+	efm_port->txirq = ret;
+
+	efm_port->port.dev = &pdev->dev;
+	efm_port->port.mapbase = res->start;
+	efm_port->port.type = PORT_EFMUART;
+	efm_port->port.iotype = UPIO_MEM32;
+	efm_port->port.fifosize = 2;
+	efm_port->port.ops = &efm32_uart_pops;
+	efm_port->port.flags = UPF_BOOT_AUTOCONF;
+
+	ret = efm32_uart_probe_dt(pdev, efm_port);
+	if (ret > 0)
+		/* not created by device tree */
+		efm_port->port.line = pdev->id;
+
+	if (efm_port->port.line >= 0 &&
+			efm_port->port.line < ARRAY_SIZE(efm32_uart_ports))
+		efm32_uart_ports[efm_port->port.line] = efm_port;
+
+	ret = uart_add_one_port(&efm32_uart_reg, &efm_port->port);
+	if (ret) {
+		dev_dbg(&pdev->dev, "failed to add port: %d\n", ret);
+
+		if (pdev->id >= 0 && pdev->id < ARRAY_SIZE(efm32_uart_ports))
+			efm32_uart_ports[pdev->id] = NULL;
+err_get_rxirq:
+err_too_small:
+err_get_base:
+		kfree(efm_port);
+	} else {
+		platform_set_drvdata(pdev, efm_port);
+		dev_dbg(&pdev->dev, "\\o/\n");
+	}
+
+	return ret;
+}
+
+static int __devexit efm32_uart_remove(struct platform_device *pdev)
+{
+	struct efm32_uart_port *efm_port = platform_get_drvdata(pdev);
+
+	platform_set_drvdata(pdev, NULL);
+
+	uart_remove_one_port(&efm32_uart_reg, &efm_port->port);
+
+	if (pdev->id >= 0 && pdev->id < ARRAY_SIZE(efm32_uart_ports))
+		efm32_uart_ports[pdev->id] = NULL;
+
+	kfree(efm_port);
+
+	return 0;
+}
+
+static struct of_device_id efm32_uart_dt_ids[] = {
+	{
+		.compatible = "efm32,uart",
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, efm32_uart_dt_ids);
+
+static struct platform_driver efm32_uart_driver = {
+	.probe = efm32_uart_probe,
+	.remove = __devexit_p(efm32_uart_remove),
+
+	.driver = {
+		.name = DRIVER_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = efm32_uart_dt_ids,
+	},
+};
+
+static int __init efm32_uart_init(void)
+{
+	int ret;
+
+	ret = uart_register_driver(&efm32_uart_reg);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&efm32_uart_driver);
+	if (ret)
+		uart_unregister_driver(&efm32_uart_reg);
+
+	pr_info("EFM32 UART/USART driver\n");
+
+	return ret;
+}
+module_init(efm32_uart_init);
+
+static void __exit efm32_uart_exit(void)
+{
+	platform_driver_unregister(&efm32_uart_driver);
+	uart_unregister_driver(&efm32_uart_reg);
+}
+
+MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
+MODULE_DESCRIPTION("EFM32 UART/USART driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);
diff --git a/include/linux/platform_data/efm32-uart.h b/include/linux/platform_data/efm32-uart.h
new file mode 100644
index 000000000000..ed0e975b3c54
--- /dev/null
+++ b/include/linux/platform_data/efm32-uart.h
@@ -0,0 +1,18 @@
+/*
+ *
+ *
+ */
+#ifndef __LINUX_PLATFORM_DATA_EFM32_UART_H__
+#define __LINUX_PLATFORM_DATA_EFM32_UART_H__
+
+#include <linux/types.h>
+
+/**
+ * struct efm32_uart_pdata
+ * @location: pinmux location for the I/O pins (to be written to the ROUTE
+ * 	register)
+ */
+struct efm32_uart_pdata {
+	u8 location;
+};
+#endif /* ifndef __LINUX_PLATFORM_DATA_EFM32_UART_H__ */
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index c91ace70c21d..585bfd03d2ee 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -210,6 +210,8 @@
 /* Atheros AR933X SoC */
 #define PORT_AR933X	99
 
+/* Energy Micro efm32 SoC */
+#define PORT_EFMUART   100
 
 #ifdef __KERNEL__
 

From d4e33fac2408d37f7b52e80ca2a89f9fb482914f Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Thu, 26 Jan 2012 17:44:09 +0000
Subject: [PATCH 05/20] serial: Kill off NO_IRQ

We transform the offenders into a test of irq <= 0 which will be ok while
the ARM people get their platform sorted. Once that is done (or in a while
if they don't do it anyway) then we will change them all to !irq checks.

For arch specific drivers that are already using NO_IRQ = 0 we just test
against zero so we don't need to re-review them later.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/tty/hvc/hvc_beat.c        |  2 +-
 drivers/tty/hvc/hvc_rtas.c        |  2 +-
 drivers/tty/hvc/hvc_udbg.c        |  2 +-
 drivers/tty/hvc/hvc_xen.c         |  2 +-
 drivers/tty/hvc/hvcs.c            |  4 ++--
 drivers/tty/hvc/hvsi.c            |  2 +-
 drivers/tty/serial/21285.c        |  4 ++--
 drivers/tty/serial/8250.c         | 21 +++++++--------------
 drivers/tty/serial/m32r_sio.c     | 11 ++---------
 drivers/tty/serial/mpc52xx_uart.c |  4 ++--
 drivers/tty/serial/mux.c          |  2 +-
 drivers/tty/serial/pmac_zilog.c   |  2 +-
 drivers/tty/serial/sunzilog.c     | 10 +++++-----
 drivers/tty/serial/ucc_uart.c     |  2 +-
 drivers/tty/serial/vr41xx_siu.c   |  4 ++--
 15 files changed, 30 insertions(+), 44 deletions(-)

diff --git a/drivers/tty/hvc/hvc_beat.c b/drivers/tty/hvc/hvc_beat.c
index 5fe4631e2a61..1560d235449e 100644
--- a/drivers/tty/hvc/hvc_beat.c
+++ b/drivers/tty/hvc/hvc_beat.c
@@ -113,7 +113,7 @@ static int __init hvc_beat_init(void)
 	if (!firmware_has_feature(FW_FEATURE_BEAT))
 		return -ENODEV;
 
-	hp = hvc_alloc(0, NO_IRQ, &hvc_beat_get_put_ops, 16);
+	hp = hvc_alloc(0, 0, &hvc_beat_get_put_ops, 16);
 	if (IS_ERR(hp))
 		return PTR_ERR(hp);
 	hvc_beat_dev = hp;
diff --git a/drivers/tty/hvc/hvc_rtas.c b/drivers/tty/hvc/hvc_rtas.c
index 61c4a61558d9..0069bb86ba49 100644
--- a/drivers/tty/hvc/hvc_rtas.c
+++ b/drivers/tty/hvc/hvc_rtas.c
@@ -94,7 +94,7 @@ static int __init hvc_rtas_init(void)
 
 	/* Allocate an hvc_struct for the console device we instantiated
 	 * earlier.  Save off hp so that we can return it on exit */
-	hp = hvc_alloc(hvc_rtas_cookie, NO_IRQ, &hvc_rtas_get_put_ops, 16);
+	hp = hvc_alloc(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops, 16);
 	if (IS_ERR(hp))
 		return PTR_ERR(hp);
 
diff --git a/drivers/tty/hvc/hvc_udbg.c b/drivers/tty/hvc/hvc_udbg.c
index b0957e61a7be..4c9b13e7748c 100644
--- a/drivers/tty/hvc/hvc_udbg.c
+++ b/drivers/tty/hvc/hvc_udbg.c
@@ -69,7 +69,7 @@ static int __init hvc_udbg_init(void)
 
 	BUG_ON(hvc_udbg_dev);
 
-	hp = hvc_alloc(0, NO_IRQ, &hvc_udbg_ops, 16);
+	hp = hvc_alloc(0, 0, &hvc_udbg_ops, 16);
 	if (IS_ERR(hp))
 		return PTR_ERR(hp);
 
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 52fdf60bdbe2..a1b0a75c3eae 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -176,7 +176,7 @@ static int __init xen_hvc_init(void)
 		xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
 	}
 	if (xencons_irq < 0)
-		xencons_irq = 0; /* NO_IRQ */
+		xencons_irq = 0;
 	else
 		irq_set_noprobe(xencons_irq);
 
diff --git a/drivers/tty/hvc/hvcs.c b/drivers/tty/hvc/hvcs.c
index b9040bec36bd..df7e7a0a5e6c 100644
--- a/drivers/tty/hvc/hvcs.c
+++ b/drivers/tty/hvc/hvcs.c
@@ -1203,7 +1203,7 @@ static void hvcs_close(struct tty_struct *tty, struct file *filp)
 {
 	struct hvcs_struct *hvcsd;
 	unsigned long flags;
-	int irq = NO_IRQ;
+	int irq;
 
 	/*
 	 * Is someone trying to close the file associated with this device after
@@ -1264,7 +1264,7 @@ static void hvcs_hangup(struct tty_struct * tty)
 	struct hvcs_struct *hvcsd = tty->driver_data;
 	unsigned long flags;
 	int temp_open_count;
-	int irq = NO_IRQ;
+	int irq;
 
 	spin_lock_irqsave(&hvcsd->lock, flags);
 	/* Preserve this so that we know how many kref refs to put */
diff --git a/drivers/tty/hvc/hvsi.c b/drivers/tty/hvc/hvsi.c
index cdfa3e02d627..1b5f28bd7930 100644
--- a/drivers/tty/hvc/hvsi.c
+++ b/drivers/tty/hvc/hvsi.c
@@ -1237,7 +1237,7 @@ static int __init hvsi_console_init(void)
 		hp->state = HVSI_CLOSED;
 		hp->vtermno = *vtermno;
 		hp->virq = irq_create_mapping(NULL, irq[0]);
-		if (hp->virq == NO_IRQ) {
+		if (hp->virq == 0) {
 			printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
 				__func__, irq[0]);
 			continue;
diff --git a/drivers/tty/serial/21285.c b/drivers/tty/serial/21285.c
index 1b37626e8f13..f899996b4363 100644
--- a/drivers/tty/serial/21285.c
+++ b/drivers/tty/serial/21285.c
@@ -331,7 +331,7 @@ static int serial21285_verify_port(struct uart_port *port, struct serial_struct
 	int ret = 0;
 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_21285)
 		ret = -EINVAL;
-	if (ser->irq != NO_IRQ)
+	if (ser->irq <= 0)
 		ret = -EINVAL;
 	if (ser->baud_base != port->uartclk / 16)
 		ret = -EINVAL;
@@ -360,7 +360,7 @@ static struct uart_ops serial21285_ops = {
 static struct uart_port serial21285_port = {
 	.mapbase	= 0x42000160,
 	.iotype		= UPIO_MEM,
-	.irq		= NO_IRQ,
+	.irq		= 0,
 	.fifosize	= 16,
 	.ops		= &serial21285_ops,
 	.flags		= UPF_BOOT_AUTOCONF,
diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c
index 9f50c4e3c2be..b0eb96139324 100644
--- a/drivers/tty/serial/8250.c
+++ b/drivers/tty/serial/8250.c
@@ -86,13 +86,6 @@ static unsigned int skip_txen_test; /* force skip of txen test at init time */
 #define BOTH_EMPTY 	(UART_LSR_TEMT | UART_LSR_THRE)
 
 
-/*
- * We default to IRQ0 for the "no irq" hack.   Some
- * machine types want others as well - they're free
- * to redefine this in their header file.
- */
-#define is_real_interrupt(irq)	((irq) != 0)
-
 #ifdef CONFIG_SERIAL_8250_DETECT_IRQ
 #define CONFIG_SERIAL_DETECT_IRQ 1
 #endif
@@ -1750,7 +1743,7 @@ static void serial8250_backup_timeout(unsigned long data)
 	 * Must disable interrupts or else we risk racing with the interrupt
 	 * based handler.
 	 */
-	if (is_real_interrupt(up->port.irq)) {
+	if (up->port.irq) {
 		ier = serial_in(up, UART_IER);
 		serial_out(up, UART_IER, 0);
 	}
@@ -1775,7 +1768,7 @@ static void serial8250_backup_timeout(unsigned long data)
 	if (!(iir & UART_IIR_NO_INT))
 		serial8250_tx_chars(up);
 
-	if (is_real_interrupt(up->port.irq))
+	if (up->port.irq)
 		serial_out(up, UART_IER, ier);
 
 	spin_unlock_irqrestore(&up->port.lock, flags);
@@ -2028,7 +2021,7 @@ static int serial8250_startup(struct uart_port *port)
 		serial_outp(up, UART_LCR, 0);
 	}
 
-	if (is_real_interrupt(up->port.irq)) {
+	if (up->port.irq) {
 		unsigned char iir1;
 		/*
 		 * Test for UARTs that do not reassert THRE when the
@@ -2083,7 +2076,7 @@ static int serial8250_startup(struct uart_port *port)
 	 * hardware interrupt, we use a timer-based system.  The original
 	 * driver used to do this with IRQ0.
 	 */
-	if (!is_real_interrupt(up->port.irq)) {
+	if (!up->port.irq) {
 		up->timer.data = (unsigned long)up;
 		mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
 	} else {
@@ -2099,13 +2092,13 @@ static int serial8250_startup(struct uart_port *port)
 
 	spin_lock_irqsave(&up->port.lock, flags);
 	if (up->port.flags & UPF_FOURPORT) {
-		if (!is_real_interrupt(up->port.irq))
+		if (!up->port.irq)
 			up->port.mctrl |= TIOCM_OUT1;
 	} else
 		/*
 		 * Most PC uarts need OUT2 raised to enable interrupts.
 		 */
-		if (is_real_interrupt(up->port.irq))
+		if (up->port.irq)
 			up->port.mctrl |= TIOCM_OUT2;
 
 	serial8250_set_mctrl(&up->port, up->port.mctrl);
@@ -2223,7 +2216,7 @@ static void serial8250_shutdown(struct uart_port *port)
 
 	del_timer_sync(&up->timer);
 	up->timer.function = serial8250_timeout;
-	if (is_real_interrupt(up->port.irq))
+	if (up->port.irq)
 		serial_unlink_irq_chain(up);
 }
 
diff --git a/drivers/tty/serial/m32r_sio.c b/drivers/tty/serial/m32r_sio.c
index 94a6792bf97b..e465dda63edf 100644
--- a/drivers/tty/serial/m32r_sio.c
+++ b/drivers/tty/serial/m32r_sio.c
@@ -70,13 +70,6 @@
 
 #define PASS_LIMIT	256
 
-/*
- * We default to IRQ0 for the "no irq" hack.   Some
- * machine types want others as well - they're free
- * to redefine this in their header file.
- */
-#define is_real_interrupt(irq)	((irq) != 0)
-
 #define BASE_BAUD	115200
 
 /* Standard COM flags */
@@ -640,7 +633,7 @@ static int m32r_sio_startup(struct uart_port *port)
 	 * hardware interrupt, we use a timer-based system.  The original
 	 * driver used to do this with IRQ0.
 	 */
-	if (!is_real_interrupt(up->port.irq)) {
+	if (!up->port.irq) {
 		unsigned int timeout = up->port.timeout;
 
 		timeout = timeout > 6 ? (timeout / 2 - 2) : 1;
@@ -687,7 +680,7 @@ static void m32r_sio_shutdown(struct uart_port *port)
 
 	sio_init();
 
-	if (!is_real_interrupt(up->port.irq))
+	if (!up->port.irq)
 		del_timer_sync(&up->timer);
 	else
 		serial_unlink_irq_chain(up);
diff --git a/drivers/tty/serial/mpc52xx_uart.c b/drivers/tty/serial/mpc52xx_uart.c
index 1093a88a1fe3..e9a770d77a6e 100644
--- a/drivers/tty/serial/mpc52xx_uart.c
+++ b/drivers/tty/serial/mpc52xx_uart.c
@@ -507,7 +507,7 @@ static int __init mpc512x_psc_fifoc_init(void)
 
 	psc_fifoc_irq = irq_of_parse_and_map(np, 0);
 	of_node_put(np);
-	if (psc_fifoc_irq == NO_IRQ) {
+	if (psc_fifoc_irq == 0) {
 		pr_err("%s: Can't get FIFOC irq\n", __func__);
 		iounmap(psc_fifoc);
 		return -ENODEV;
@@ -1354,7 +1354,7 @@ static int __devinit mpc52xx_uart_of_probe(struct platform_device *op)
 	}
 
 	psc_ops->get_irq(port, op->dev.of_node);
-	if (port->irq == NO_IRQ) {
+	if (port->irq == 0) {
 		dev_dbg(&op->dev, "Could not get irq\n");
 		return -EINVAL;
 	}
diff --git a/drivers/tty/serial/mux.c b/drivers/tty/serial/mux.c
index 06f6aefd5ba6..c61d950e07c1 100644
--- a/drivers/tty/serial/mux.c
+++ b/drivers/tty/serial/mux.c
@@ -499,7 +499,7 @@ static int __init mux_probe(struct parisc_device *dev)
 		port->membase	= ioremap_nocache(port->mapbase, MUX_LINE_OFFSET);
 		port->iotype	= UPIO_MEM;
 		port->type	= PORT_MUX;
-		port->irq	= NO_IRQ;
+		port->irq	= 0;
 		port->uartclk	= 0;
 		port->fifosize	= MUX_FIFO_SIZE;
 		port->ops	= &mux_pops;
diff --git a/drivers/tty/serial/pmac_zilog.c b/drivers/tty/serial/pmac_zilog.c
index e9c2dfe471a2..08ebe901bb59 100644
--- a/drivers/tty/serial/pmac_zilog.c
+++ b/drivers/tty/serial/pmac_zilog.c
@@ -1506,7 +1506,7 @@ no_dma:
 	 * fixed up interrupt info, but we use the device-tree directly
 	 * here due to early probing so we need the fixup too.
 	 */
-	if (uap->port.irq == NO_IRQ &&
+	if (uap->port.irq == 0 &&
 	    np->parent && np->parent->parent &&
 	    of_device_is_compatible(np->parent->parent, "gatwick")) {
 		/* IRQs on gatwick are offset by 64 */
diff --git a/drivers/tty/serial/sunzilog.c b/drivers/tty/serial/sunzilog.c
index 8e916e76b7b5..5a47d1b196d8 100644
--- a/drivers/tty/serial/sunzilog.c
+++ b/drivers/tty/serial/sunzilog.c
@@ -1397,7 +1397,7 @@ static void __devinit sunzilog_init_hw(struct uart_sunzilog_port *up)
 #endif
 }
 
-static int zilog_irq = -1;
+static int zilog_irq;
 
 static int __devinit zs_probe(struct platform_device *op)
 {
@@ -1425,7 +1425,7 @@ static int __devinit zs_probe(struct platform_device *op)
 
 	rp = sunzilog_chip_regs[inst];
 
-	if (zilog_irq == -1)
+	if (!zilog_irq)
 		zilog_irq = op->archdata.irqs[0];
 
 	up = &sunzilog_port_table[inst * 2];
@@ -1580,7 +1580,7 @@ static int __init sunzilog_init(void)
 	if (err)
 		goto out_unregister_uart;
 
-	if (zilog_irq != -1) {
+	if (!zilog_irq) {
 		struct uart_sunzilog_port *up = sunzilog_irq_chain;
 		err = request_irq(zilog_irq, sunzilog_interrupt, IRQF_SHARED,
 				  "zs", sunzilog_irq_chain);
@@ -1621,7 +1621,7 @@ static void __exit sunzilog_exit(void)
 {
 	platform_driver_unregister(&zs_driver);
 
-	if (zilog_irq != -1) {
+	if (!zilog_irq) {
 		struct uart_sunzilog_port *up = sunzilog_irq_chain;
 
 		/* Disable Interrupts */
@@ -1637,7 +1637,7 @@ static void __exit sunzilog_exit(void)
 		}
 
 		free_irq(zilog_irq, sunzilog_irq_chain);
-		zilog_irq = -1;
+		zilog_irq = 0;
 	}
 
 	if (sunzilog_reg.nr) {
diff --git a/drivers/tty/serial/ucc_uart.c b/drivers/tty/serial/ucc_uart.c
index 2ebe606a2db1..f99b0c965f85 100644
--- a/drivers/tty/serial/ucc_uart.c
+++ b/drivers/tty/serial/ucc_uart.c
@@ -1360,7 +1360,7 @@ static int ucc_uart_probe(struct platform_device *ofdev)
 	}
 
 	qe_port->port.irq = irq_of_parse_and_map(np, 0);
-	if (qe_port->port.irq == NO_IRQ) {
+	if (qe_port->port.irq == 0) {
 		dev_err(&ofdev->dev, "could not map IRQ for UCC%u\n",
 		       qe_port->ucc_num + 1);
 		ret = -EINVAL;
diff --git a/drivers/tty/serial/vr41xx_siu.c b/drivers/tty/serial/vr41xx_siu.c
index 83148e79ca13..cf0d9485ec08 100644
--- a/drivers/tty/serial/vr41xx_siu.c
+++ b/drivers/tty/serial/vr41xx_siu.c
@@ -61,7 +61,7 @@
 static struct uart_port siu_uart_ports[SIU_PORTS_MAX] = {
 	[0 ... SIU_PORTS_MAX-1] = {
 		.lock	= __SPIN_LOCK_UNLOCKED(siu_uart_ports->lock),
-		.irq	= -1,
+		.irq	= 0,
 	},
 };
 
@@ -171,7 +171,7 @@ static inline unsigned int siu_check_type(struct uart_port *port)
 {
 	if (port->line == 0)
 		return PORT_VR41XX_SIU;
-	if (port->line == 1 && port->irq != -1)
+	if (port->line == 1 && port->irq)
 		return PORT_VR41XX_DSIU;
 
 	return PORT_UNKNOWN;

From 5816269e4ee3db2bc2ad44afc89f4abe81c7aa26 Mon Sep 17 00:00:00 2001
From: Paul Walmsley <paul@pwsan.com>
Date: Wed, 25 Jan 2012 19:50:36 -0700
Subject: [PATCH 06/20] tty: serial: OMAP: use a 1-byte RX FIFO threshold in
 PIO mode

In the (default) PIO mode, use a one-byte RX FIFO threshold.  The OMAP
UART IP blocks do not appear to be capable of waking the system under
an RX timeout condition.  Since the previous RX FIFO threshold was 16
bytes, this meant that omap-serial.c did not become aware of any
received data until all those bytes arrived or until another UART
interrupt occurred.  This made the serial console and presumably other
serial applications (GPS, serial Bluetooth) unusable or extremely
slow.  A 1-byte RX FIFO threshold also allows the MPU to enter a
low-power consumption state while waiting for the FIFO to fill.

This can be verified using the serial console by comparing the
behavior when "0123456789abcde" is pasted in from another window, with
the behavior when "0123456789abcdef" is pasted in.  Since the former
string is less than sixteen bytes long, the string is not echoed for
some time, while the latter string is echoed immediately.

DMA operation is unaffected by this patch.

Thanks to Russell King - ARM Linux <linux@arm.linux.org.uk> for some
additional information on the standard behavior of the RX timeout
event, which was used to improve this commit description.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Govindraj Raja <govindraj.r@ti.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/omap-serial.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index d192dcbb82f5..c9c9ba2a5bb6 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -46,6 +46,13 @@
 
 #define DEFAULT_CLK_SPEED 48000000 /* 48Mhz*/
 
+/* SCR register bitmasks */
+#define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK		(1 << 7)
+
+/* FCR register bitmasks */
+#define OMAP_UART_FCR_RX_FIFO_TRIG_SHIFT		6
+#define OMAP_UART_FCR_RX_FIFO_TRIG_MASK			(0x3 << 6)
+
 static struct uart_omap_port *ui[OMAP_MAX_HSUART_PORTS];
 
 /* Forward declaration of functions */
@@ -811,14 +818,21 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
 	up->mcr = serial_in(up, UART_MCR);
 	serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);
 	/* FIFO ENABLE, DMA MODE */
-	serial_out(up, UART_FCR, up->fcr);
-	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+
+	up->scr |= OMAP_UART_SCR_RX_TRIG_GRANU1_MASK;
 
 	if (up->use_dma) {
 		serial_out(up, UART_TI752_TLR, 0);
-		up->scr |= (UART_FCR_TRIGGER_4 | UART_FCR_TRIGGER_8);
+		up->scr |= UART_FCR_TRIGGER_4;
+	} else {
+		/* Set receive FIFO threshold to 1 byte */
+		up->fcr &= ~OMAP_UART_FCR_RX_FIFO_TRIG_MASK;
+		up->fcr |= (0x1 << OMAP_UART_FCR_RX_FIFO_TRIG_SHIFT);
 	}
 
+	serial_out(up, UART_FCR, up->fcr);
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+
 	serial_out(up, UART_OMAP_SCR, up->scr);
 
 	serial_out(up, UART_EFR, up->efr);

From edbe5dbefe5b514d094558ab59c8dc7578e117dd Mon Sep 17 00:00:00 2001
From: Paul Walmsley <paul@pwsan.com>
Date: Wed, 25 Jan 2012 19:50:52 -0700
Subject: [PATCH 07/20] tty: serial: OMAP: block idle while the UART is
 transferring data in PIO mode

Prevent OMAP UARTs from going idle while they are still transferring
data in PIO mode.  This works around an oversight in the OMAP UART
hardware present in OMAP34xx and earlier: an idle UART won't send a
wakeup when the TX FIFO threshold is reached.  This causes long delays
during data transmission when the MPU powerdomain enters a low-power
mode.  The MPU interrupt controller is not able to respond to
interrupts when it's in a low-power state, so the TX buffer is not
refilled until another wakeup event occurs.

This fix changes the erratum i291 DMA idle workaround.  Rather than
toggling between force-idle and no-idle, it will toggle between
smart-idle and no-idle.  The important part of the workaround is the
no-idle part, so this shouldn't result in any change in behavior.

This fix should work on all OMAP UARTs.  Future patches intended for
the 3.4 merge window will make this workaround conditional on a
"feature" flag, and will use the OMAP36xx+ TX event wakeup support.

Thanks to Kevin Hilman <khilman@ti.com> for mentioning the erratum i291
workaround, which led to the development of this approach.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm/mach-omap2/serial.c     | 8 ++++----
 drivers/tty/serial/omap-serial.c | 7 +++++++
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 247d89478f24..f590afc1f673 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -107,18 +107,18 @@ static void omap_uart_set_noidle(struct platform_device *pdev)
 	omap_hwmod_set_slave_idlemode(od->hwmods[0], HWMOD_IDLEMODE_NO);
 }
 
-static void omap_uart_set_forceidle(struct platform_device *pdev)
+static void omap_uart_set_smartidle(struct platform_device *pdev)
 {
 	struct omap_device *od = to_omap_device(pdev);
 
-	omap_hwmod_set_slave_idlemode(od->hwmods[0], HWMOD_IDLEMODE_FORCE);
+	omap_hwmod_set_slave_idlemode(od->hwmods[0], HWMOD_IDLEMODE_SMART);
 }
 
 #else
 static void omap_uart_enable_wakeup(struct platform_device *pdev, bool enable)
 {}
 static void omap_uart_set_noidle(struct platform_device *pdev) {}
-static void omap_uart_set_forceidle(struct platform_device *pdev) {}
+static void omap_uart_set_smartidle(struct platform_device *pdev) {}
 #endif /* CONFIG_PM */
 
 #ifdef CONFIG_OMAP_MUX
@@ -349,7 +349,7 @@ void __init omap_serial_init_port(struct omap_board_data *bdata,
 	omap_up.uartclk = OMAP24XX_BASE_BAUD * 16;
 	omap_up.flags = UPF_BOOT_AUTOCONF;
 	omap_up.get_context_loss_count = omap_pm_get_dev_context_loss_count;
-	omap_up.set_forceidle = omap_uart_set_forceidle;
+	omap_up.set_forceidle = omap_uart_set_smartidle;
 	omap_up.set_noidle = omap_uart_set_noidle;
 	omap_up.enable_wakeup = omap_uart_enable_wakeup;
 	omap_up.dma_rx_buf_size = info->dma_rx_buf_size;
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index c9c9ba2a5bb6..11fa15623e13 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -136,6 +136,7 @@ static void serial_omap_enable_ms(struct uart_port *port)
 static void serial_omap_stop_tx(struct uart_port *port)
 {
 	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct omap_uart_port_info *pdata = up->pdev->dev.platform_data;
 
 	if (up->use_dma &&
 		up->uart_dma.tx_dma_channel != OMAP_UART_DMA_CH_FREE) {
@@ -158,6 +159,9 @@ static void serial_omap_stop_tx(struct uart_port *port)
 		serial_out(up, UART_IER, up->ier);
 	}
 
+	if (!up->use_dma && pdata->set_forceidle)
+		pdata->set_forceidle(up->pdev);
+
 	pm_runtime_mark_last_busy(&up->pdev->dev);
 	pm_runtime_put_autosuspend(&up->pdev->dev);
 }
@@ -286,6 +290,7 @@ static inline void serial_omap_enable_ier_thri(struct uart_omap_port *up)
 static void serial_omap_start_tx(struct uart_port *port)
 {
 	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct omap_uart_port_info *pdata = up->pdev->dev.platform_data;
 	struct circ_buf *xmit;
 	unsigned int start;
 	int ret = 0;
@@ -293,6 +298,8 @@ static void serial_omap_start_tx(struct uart_port *port)
 	if (!up->use_dma) {
 		pm_runtime_get_sync(&up->pdev->dev);
 		serial_omap_enable_ier_thri(up);
+		if (pdata->set_noidle)
+			pdata->set_noidle(up->pdev);
 		pm_runtime_mark_last_busy(&up->pdev->dev);
 		pm_runtime_put_autosuspend(&up->pdev->dev);
 		return;

From 6bbcbf22085e0b144899d6067e243dd26c0e7533 Mon Sep 17 00:00:00 2001
From: Paul Walmsley <paul@pwsan.com>
Date: Wed, 25 Jan 2012 19:50:56 -0700
Subject: [PATCH 08/20] tty: serial: omap-serial: wakeup latency constraint is
 in microseconds, not milliseconds

The receive FIFO wakeup latency estimate in the omap-serial driver is
three orders of magnitude too small.  This effectively prevents the
MPU from going to a low-power state when CONFIG_CPU_IDLE=y.  This is a
major power management regression and masks some other FIFO-related
bugs in the driver.

Fix by correcting the most egregious problem in the RX wakeup latency
estimate.  There are several other flaws in the estimator; these will
be fixed by a separate patch series intended for 3.4.

The difference in low-power states with this patch can be observed via
debugfs in pm_debug/count.

This estimate does not have any effect when CONFIG_CPU_IDLE=n.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/omap-serial.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 11fa15623e13..72fa783729d2 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -740,8 +740,7 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
 	quot = serial_omap_get_divisor(port, baud);
 
 	/* calculate wakeup latency constraint */
-	up->calc_latency = (1000000 * up->port.fifosize) /
-				(1000 * baud / 8);
+	up->calc_latency = (USEC_PER_SEC * up->port.fifosize) / (baud / 8);
 	up->latency = up->calc_latency;
 	schedule_work(&up->qos_work);
 

From 66d450e84ec656ec4b774c41cd8d46b3e48d51df Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Mon, 30 Jan 2012 21:14:28 +0100
Subject: [PATCH 09/20] TTY: provide tty_standard_install helper

There are currently many cut&paste copies of what
tty_driver_install_tty does when custom ->install method is not
provided. Let's get rid of the copies and create a helper with this
setup code.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Havard Skinnemoen <hskinnemoen@google.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/tty_io.c | 30 +++++++++++++++---------------
 include/linux/tty.h  |  2 ++
 2 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index fbcc14063804..44736f9e61d7 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1271,6 +1271,19 @@ int tty_init_termios(struct tty_struct *tty)
 }
 EXPORT_SYMBOL_GPL(tty_init_termios);
 
+int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
+{
+	int ret = tty_init_termios(tty);
+	if (ret)
+		return ret;
+
+	tty_driver_kref_get(driver);
+	tty->count++;
+	driver->ttys[tty->index] = tty;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tty_standard_install);
+
 /**
  *	tty_driver_install_tty() - install a tty entry in the driver
  *	@driver: the driver for the tty
@@ -1286,21 +1299,8 @@ EXPORT_SYMBOL_GPL(tty_init_termios);
 static int tty_driver_install_tty(struct tty_driver *driver,
 						struct tty_struct *tty)
 {
-	int idx = tty->index;
-	int ret;
-
-	if (driver->ops->install) {
-		ret = driver->ops->install(driver, tty);
-		return ret;
-	}
-
-	if (tty_init_termios(tty) == 0) {
-		tty_driver_kref_get(driver);
-		tty->count++;
-		driver->ttys[idx] = tty;
-		return 0;
-	}
-	return -ENOMEM;
+	return driver->ops->install ? driver->ops->install(driver, tty) :
+		tty_standard_install(driver, tty);
 }
 
 /**
diff --git a/include/linux/tty.h b/include/linux/tty.h
index d40774188203..a91ff403b3bf 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -484,6 +484,8 @@ extern void deinitialize_tty_struct(struct tty_struct *tty);
 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
 extern int tty_release(struct inode *inode, struct file *filp);
 extern int tty_init_termios(struct tty_struct *tty);
+extern int tty_standard_install(struct tty_driver *driver,
+		struct tty_struct *tty);
 
 extern struct tty_struct *tty_pair_get_tty(struct tty_struct *tty);
 extern struct tty_struct *tty_pair_get_pty(struct tty_struct *tty);

From 76f82a7ab3a724791d184e74529e96ad6947a98f Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Mon, 30 Jan 2012 21:14:29 +0100
Subject: [PATCH 10/20] USB: serial, use tty_standard_install

But before that we need to reorder the calls so that we don't need to
lower the reference counts if usb_autopm_get_interface fails.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/serial/usb-serial.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 611b206591cb..1e30cc92719c 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -214,15 +214,14 @@ static int serial_install(struct tty_driver *driver, struct tty_struct *tty)
 	if (!try_module_get(serial->type->driver.owner))
 		goto error_module_get;
 
-	/* perform the standard setup */
-	retval = tty_init_termios(tty);
-	if (retval)
-		goto error_init_termios;
-
 	retval = usb_autopm_get_interface(serial->interface);
 	if (retval)
 		goto error_get_interface;
 
+	retval = tty_standard_install(driver, tty);
+	if (retval)
+		goto error_init_termios;
+
 	mutex_unlock(&serial->disc_mutex);
 
 	/* allow the driver to update the settings */
@@ -231,14 +230,11 @@ static int serial_install(struct tty_driver *driver, struct tty_struct *tty)
 
 	tty->driver_data = port;
 
-	/* Final install (we use the default method) */
-	tty_driver_kref_get(driver);
-	tty->count++;
-	driver->ttys[idx] = tty;
 	return retval;
 
- error_get_interface:
  error_init_termios:
+	usb_autopm_put_interface(serial->interface);
+ error_get_interface:
 	module_put(serial->type->driver.owner);
  error_module_get:
  error_no_port:

From 81f5835eae424be646753ec5a044ed4db1fcc09a Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Mon, 30 Jan 2012 21:14:30 +0100
Subject: [PATCH 11/20] TTY: use tty_standard_install

Use the helper in the rest of the tty drivers. This is a simple
replacement.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/isdn/capi/capi.c     | 9 +++------
 drivers/misc/pti.c           | 6 +-----
 drivers/mmc/card/sdio_uart.c | 9 +++------
 drivers/tty/nozomi.c         | 8 ++------
 4 files changed, 9 insertions(+), 23 deletions(-)

diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index e44933d58790..94948be5d366 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -1015,14 +1015,11 @@ capinc_tty_install(struct tty_driver *driver, struct tty_struct *tty)
 {
 	int idx = tty->index;
 	struct capiminor *mp = capiminor_get(idx);
-	int ret = tty_init_termios(tty);
+	int ret = tty_standard_install(driver, tty);
 
-	if (ret == 0) {
-		tty_driver_kref_get(driver);
-		tty->count++;
+	if (ret == 0)
 		tty->driver_data = mp;
-		driver->ttys[idx] = tty;
-	} else
+	else
 		capiminor_put(mp);
 	return ret;
 }
diff --git a/drivers/misc/pti.c b/drivers/misc/pti.c
index 0b56e3f43573..471ff4c85cd8 100644
--- a/drivers/misc/pti.c
+++ b/drivers/misc/pti.c
@@ -481,13 +481,9 @@ static int pti_tty_install(struct tty_driver *driver, struct tty_struct *tty)
 {
 	int idx = tty->index;
 	struct pti_tty *pti_tty_data;
-	int ret = tty_init_termios(tty);
+	int ret = tty_standard_install(driver, tty);
 
 	if (ret == 0) {
-		tty_driver_kref_get(driver);
-		tty->count++;
-		driver->ttys[idx] = tty;
-
 		pti_tty_data = kmalloc(sizeof(struct pti_tty), GFP_KERNEL);
 		if (pti_tty_data == NULL)
 			return -ENOMEM;
diff --git a/drivers/mmc/card/sdio_uart.c b/drivers/mmc/card/sdio_uart.c
index 2c151e18c9e8..bd4a67cdac3f 100644
--- a/drivers/mmc/card/sdio_uart.c
+++ b/drivers/mmc/card/sdio_uart.c
@@ -750,15 +750,12 @@ static int sdio_uart_install(struct tty_driver *driver, struct tty_struct *tty)
 {
 	int idx = tty->index;
 	struct sdio_uart_port *port = sdio_uart_port_get(idx);
-	int ret = tty_init_termios(tty);
+	int ret = tty_standard_install(driver, tty);
 
-	if (ret == 0) {
-		tty_driver_kref_get(driver);
-		tty->count++;
+	if (ret == 0)
 		/* This is the ref sdio_uart_port get provided */
 		tty->driver_data = port;
-		driver->ttys[idx] = tty;
-	} else
+	else
 		sdio_uart_port_put(port);
 	return ret;
 }
diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index fd347ff34d07..580da78b2d86 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -1602,13 +1602,9 @@ static int ntty_install(struct tty_driver *driver, struct tty_struct *tty)
 	int ret;
 	if (!port || !dc || dc->state != NOZOMI_STATE_READY)
 		return -ENODEV;
-	ret = tty_init_termios(tty);
-	if (ret == 0) {
-		tty_driver_kref_get(driver);
-		tty->count++;
+	ret = tty_standard_install(driver, tty);
+	if (ret == 0)
 		tty->driver_data = port;
-		driver->ttys[tty->index] = tty;
-	}
 	return ret;
 }
 

From a50f724a432997321cabb6c9e665c28e34850f78 Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Mon, 30 Jan 2012 21:14:31 +0100
Subject: [PATCH 12/20] TTY: pty, remove superfluous ptm test

The code looks like:
if (tty->driver->subtype == PTY_TYPE_MASTER) {
  ...
  if (tty->driver == ptm_driver)

But the second if is superfluous because only the ptm_driver is of
PTY_TYPE_MASTER subtype.

Also we can remove the #if now because devpts_pty_kill is defined as
an empty function for non-CONFIG_UNIX98_PTYS configs.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/pty.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index d505837b3478..ddec9f3c3396 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -54,10 +54,7 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
 	wake_up_interruptible(&tty->link->write_wait);
 	if (tty->driver->subtype == PTY_TYPE_MASTER) {
 		set_bit(TTY_OTHER_CLOSED, &tty->flags);
-#ifdef CONFIG_UNIX98_PTYS
-		if (tty->driver == ptm_driver)
-			devpts_pty_kill(tty->link);
-#endif
+		devpts_pty_kill(tty->link);
 		tty_unlock();
 		tty_vhangup(tty->link);
 		tty_lock();

From d3bda5298aad98c7a27678bdd0dd9d008ab9e685 Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Mon, 30 Jan 2012 21:14:32 +0100
Subject: [PATCH 13/20] TTY: get rid of BTM around devpts_*

devpts operations are protected by inode mutexes and dentry
refcounting. There is no need to hold BTM.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/pty.c    | 6 ++----
 drivers/tty/tty_io.c | 2 +-
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index ddec9f3c3396..39afd045f8ef 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -54,8 +54,8 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
 	wake_up_interruptible(&tty->link->write_wait);
 	if (tty->driver->subtype == PTY_TYPE_MASTER) {
 		set_bit(TTY_OTHER_CLOSED, &tty->flags);
-		devpts_pty_kill(tty->link);
 		tty_unlock();
+		devpts_pty_kill(tty->link);
 		tty_vhangup(tty->link);
 		tty_lock();
 	}
@@ -613,9 +613,7 @@ static int ptmx_open(struct inode *inode, struct file *filp)
 		return retval;
 
 	/* find a device that is not in use. */
-	tty_lock();
 	index = devpts_new_index(inode);
-	tty_unlock();
 	if (index < 0) {
 		retval = index;
 		goto err_file;
@@ -650,8 +648,8 @@ err_release:
 	tty_release(inode, filp);
 	return retval;
 out:
-	devpts_kill_index(inode, index);
 	tty_unlock();
+	devpts_kill_index(inode, index);
 err_file:
 	tty_free_file(filp);
 	return retval;
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 44736f9e61d7..ea7ebe22a16c 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1789,11 +1789,11 @@ int tty_release(struct inode *inode, struct file *filp)
 	 * the slots and preserving the termios structure.
 	 */
 	release_tty(tty, idx);
+	tty_unlock();
 
 	/* Make this pty number available for reallocation */
 	if (devpts)
 		devpts_kill_index(inode, idx);
-	tty_unlock();
 	return 0;
 }
 

From d011411ddb294e90511211a9edfc79da1c0465dc Mon Sep 17 00:00:00 2001
From: Feng Tang <feng.tang@intel.com>
Date: Mon, 6 Feb 2012 17:24:43 +0800
Subject: [PATCH 14/20] serial: pch_uart: add debugfs hook for register dump

This driver will be use as interfaces for multiple kinds of
devices like Bluetooth/GPS etc, this debug hook will make driver
debugging much easier.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/pch_uart.c | 84 +++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 17ae65762d1a..6d9ca2933361 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -29,6 +29,7 @@
 #include <linux/nmi.h>
 #include <linux/delay.h>
 
+#include <linux/debugfs.h>
 #include <linux/dmaengine.h>
 #include <linux/pch_dma.h>
 
@@ -144,6 +145,8 @@ enum {
 #define PCH_UART_DLL		0x00
 #define PCH_UART_DLM		0x01
 
+#define PCH_UART_BRCSR		0x0E
+
 #define PCH_UART_IID_RLS	(PCH_UART_IIR_REI)
 #define PCH_UART_IID_RDR	(PCH_UART_IIR_RRI)
 #define PCH_UART_IID_RDR_TO	(PCH_UART_IIR_RRI | PCH_UART_IIR_TOI)
@@ -243,6 +246,8 @@ struct eg20t_port {
 	int				tx_dma_use;
 	void				*rx_buf_virt;
 	dma_addr_t			rx_buf_dma;
+
+	struct dentry	*debugfs;
 };
 
 /**
@@ -292,6 +297,73 @@ static const int trigger_level_64[4] = { 1, 16, 32, 56 };
 static const int trigger_level_16[4] = { 1, 4, 8, 14 };
 static const int trigger_level_1[4] = { 1, 1, 1, 1 };
 
+#ifdef CONFIG_DEBUG_FS
+
+#define PCH_REGS_BUFSIZE	1024
+static int pch_show_regs_open(struct inode *inode, struct file *file)
+{
+	file->private_data = inode->i_private;
+	return 0;
+}
+
+static ssize_t port_show_regs(struct file *file, char __user *user_buf,
+				size_t count, loff_t *ppos)
+{
+	struct eg20t_port *priv = file->private_data;
+	char *buf;
+	u32 len = 0;
+	ssize_t ret;
+	unsigned char lcr;
+
+	buf = kzalloc(PCH_REGS_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return 0;
+
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"PCH EG20T port[%d] regs:\n", priv->port.line);
+
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"=================================\n");
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"IER: \t0x%02x\n", ioread8(priv->membase + UART_IER));
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"IIR: \t0x%02x\n", ioread8(priv->membase + UART_IIR));
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"LCR: \t0x%02x\n", ioread8(priv->membase + UART_LCR));
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"MCR: \t0x%02x\n", ioread8(priv->membase + UART_MCR));
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"LSR: \t0x%02x\n", ioread8(priv->membase + UART_LSR));
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"MSR: \t0x%02x\n", ioread8(priv->membase + UART_MSR));
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"BRCSR: \t0x%02x\n",
+			ioread8(priv->membase + PCH_UART_BRCSR));
+
+	lcr = ioread8(priv->membase + UART_LCR);
+	iowrite8(PCH_UART_LCR_DLAB, priv->membase + UART_LCR);
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"DLL: \t0x%02x\n", ioread8(priv->membase + UART_DLL));
+	len += snprintf(buf + len, PCH_REGS_BUFSIZE - len,
+			"DLM: \t0x%02x\n", ioread8(priv->membase + UART_DLM));
+	iowrite8(lcr, priv->membase + UART_LCR);
+
+	if (len > PCH_REGS_BUFSIZE)
+		len = PCH_REGS_BUFSIZE;
+
+	ret =  simple_read_from_buffer(user_buf, count, ppos, buf, len);
+	kfree(buf);
+	return ret;
+}
+
+static const struct file_operations port_regs_ops = {
+	.owner		= THIS_MODULE,
+	.open		= pch_show_regs_open,
+	.read		= port_show_regs,
+	.llseek		= default_llseek,
+};
+#endif	/* CONFIG_DEBUG_FS */
+
 static void pch_uart_hal_request(struct pci_dev *pdev, int fifosize,
 				 int base_baud)
 {
@@ -1554,6 +1626,7 @@ static struct eg20t_port *pch_uart_init_port(struct pci_dev *pdev,
 	int port_type;
 	struct pch_uart_driver_data *board;
 	const char *board_name;
+	char name[32];	/* for debugfs file name */
 
 	board = &drv_dat[id->driver_data];
 	port_type = board->port_type;
@@ -1623,6 +1696,12 @@ static struct eg20t_port *pch_uart_init_port(struct pci_dev *pdev,
 	if (ret < 0)
 		goto init_port_hal_free;
 
+#ifdef CONFIG_DEBUG_FS
+	snprintf(name, sizeof(name), "uart%d_regs", board->line_no);
+	priv->debugfs = debugfs_create_file(name, S_IFREG | S_IRUGO,
+				NULL, priv, &port_regs_ops);
+#endif
+
 	return priv;
 
 init_port_hal_free:
@@ -1639,6 +1718,11 @@ init_port_alloc_err:
 
 static void pch_uart_exit_port(struct eg20t_port *priv)
 {
+
+#ifdef CONFIG_DEBUG_FS
+	if (priv->debugfs)
+		debugfs_remove(priv->debugfs);
+#endif
 	uart_remove_one_port(&pch_uart_driver, &priv->port);
 	pci_set_drvdata(priv->pdev, NULL);
 	free_page((unsigned long)priv->rxbuf.buf);

From 30c6c6b5bf82d4f4a23235a0aa0657681d1c21f2 Mon Sep 17 00:00:00 2001
From: Feng Tang <feng.tang@intel.com>
Date: Mon, 6 Feb 2012 17:24:44 +0800
Subject: [PATCH 15/20] serial: pch_uart: trivial cleanup by removing the
 get_msr()

The short get_msr() has some unnecessary code and only used once,
so merge it with its caller to make code cleaner. No functional
change at all.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/pch_uart.c | 29 ++++++++---------------------
 1 file changed, 8 insertions(+), 21 deletions(-)

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 6d9ca2933361..811edcbe7304 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -373,14 +373,6 @@ static void pch_uart_hal_request(struct pci_dev *pdev, int fifosize,
 	priv->fcr = 0;
 }
 
-static unsigned int get_msr(struct eg20t_port *priv, void __iomem *base)
-{
-	unsigned int msr = ioread8(base + UART_MSR);
-	priv->dmsr |= msr & PCH_UART_MSR_DELTA;
-
-	return msr;
-}
-
 static void pch_uart_hal_enable_interrupt(struct eg20t_port *priv,
 					  unsigned int flag)
 {
@@ -514,8 +506,9 @@ static int pch_uart_hal_set_fifo(struct eg20t_port *priv,
 
 static u8 pch_uart_hal_get_modem(struct eg20t_port *priv)
 {
-	priv->dmsr = 0;
-	return get_msr(priv, priv->membase);
+	unsigned int msr = ioread8(priv->membase + UART_MSR);
+	priv->dmsr = msr & PCH_UART_MSR_DELTA;
+	return (u8)msr;
 }
 
 static void pch_uart_hal_write(struct eg20t_port *priv,
@@ -596,7 +589,7 @@ static int push_rx(struct eg20t_port *priv, const unsigned char *buf,
 
 static int pop_tx_x(struct eg20t_port *priv, unsigned char *buf)
 {
-	int ret;
+	int ret = 0;
 	struct uart_port *port = &priv->port;
 
 	if (port->x_char) {
@@ -605,8 +598,6 @@ static int pop_tx_x(struct eg20t_port *priv, unsigned char *buf)
 		buf[0] = port->x_char;
 		port->x_char = 0;
 		ret = 1;
-	} else {
-		ret = 0;
 	}
 
 	return ret;
@@ -1104,14 +1095,12 @@ static irqreturn_t pch_uart_interrupt(int irq, void *dev_id)
 static unsigned int pch_uart_tx_empty(struct uart_port *port)
 {
 	struct eg20t_port *priv;
-	int ret;
+
 	priv = container_of(port, struct eg20t_port, port);
 	if (priv->tx_empty)
-		ret = TIOCSER_TEMT;
+		return TIOCSER_TEMT;
 	else
-		ret = 0;
-
-	return ret;
+		return 0;
 }
 
 /* Returns the current state of modem control inputs. */
@@ -1345,9 +1334,8 @@ static void pch_uart_set_termios(struct uart_port *port,
 		else
 			parity = PCH_UART_HAL_PARITY_EVEN;
 
-	} else {
+	} else
 		parity = PCH_UART_HAL_PARITY_NONE;
-	}
 
 	/* Only UART0 has auto hardware flow function */
 	if ((termios->c_cflag & CRTSCTS) && (priv->fifo_size == 256))
@@ -1519,7 +1507,6 @@ static void
 pch_console_write(struct console *co, const char *s, unsigned int count)
 {
 	struct eg20t_port *priv;
-
 	unsigned long flags;
 	u8 ier;
 	int locked = 1;

From 6f56d0f43656deb98c6366a133a75b5a7cf73a26 Mon Sep 17 00:00:00 2001
From: Feng Tang <feng.tang@intel.com>
Date: Mon, 6 Feb 2012 17:24:45 +0800
Subject: [PATCH 16/20] serial: pch_uart: trivail cleanup by removing the
 pch_uart_hal_request()

pch_uart_hal_request() has parameters which it never uses, also
it is very short, so merge it with its caller to make code cleaner.
No functional changes at all.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/pch_uart.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 811edcbe7304..aa4d07b4a9d5 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -364,15 +364,6 @@ static const struct file_operations port_regs_ops = {
 };
 #endif	/* CONFIG_DEBUG_FS */
 
-static void pch_uart_hal_request(struct pci_dev *pdev, int fifosize,
-				 int base_baud)
-{
-	struct eg20t_port *priv = pci_get_drvdata(pdev);
-
-	priv->trigger_level = 1;
-	priv->fcr = 0;
-}
-
 static void pch_uart_hal_enable_interrupt(struct eg20t_port *priv,
 					  unsigned int flag)
 {
@@ -1674,7 +1665,8 @@ static struct eg20t_port *pch_uart_init_port(struct pci_dev *pdev,
 	spin_lock_init(&priv->port.lock);
 
 	pci_set_drvdata(pdev, priv);
-	pch_uart_hal_request(pdev, fifosize, base_baud);
+	priv->trigger_level = 1;
+	priv->fcr = 0;
 
 #ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
 	pch_uart_ports[board->line_no] = priv;
@@ -1717,9 +1709,7 @@ static void pch_uart_exit_port(struct eg20t_port *priv)
 
 static void pch_uart_pci_remove(struct pci_dev *pdev)
 {
-	struct eg20t_port *priv;
-
-	priv = (struct eg20t_port *)pci_get_drvdata(pdev);
+	struct eg20t_port *priv = pci_get_drvdata(pdev);
 
 	pci_disable_msi(pdev);
 

From e502babe0a85226f2417b60a8710cf8192879180 Mon Sep 17 00:00:00 2001
From: Anton Vorontsov <anton.vorontsov@linaro.org>
Date: Tue, 7 Feb 2012 10:49:39 +0400
Subject: [PATCH 17/20] sysrq: Fix possible race with exiting task

sysrq should grab the tasklist lock, otherwise calling force_sig() is
not safe, as it might race with exiting task, which ->sighand might be
set to NULL already.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/sysrq.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 7867b7c4538e..a1bcad7ef739 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -322,11 +322,13 @@ static void send_sig_all(int sig)
 {
 	struct task_struct *p;
 
+	read_lock(&tasklist_lock);
 	for_each_process(p) {
 		if (p->mm && !is_global_init(p))
 			/* Not swapper, init nor kernel thread */
 			force_sig(sig, p);
 	}
+	read_unlock(&tasklist_lock);
 }
 
 static void sysrq_handle_term(int key)

From d3a532a9c617106a0169232d40164ee35d0440b5 Mon Sep 17 00:00:00 2001
From: Anton Vorontsov <anton.vorontsov@linaro.org>
Date: Tue, 7 Feb 2012 10:49:51 +0400
Subject: [PATCH 18/20] sysrq: Properly check for kernel threads

There's a real possibility of killing kernel threads that might
have issued use_mm(), so kthread's mm might become non-NULL.

This patch fixes the issue by checking for PF_KTHREAD (just as
get_task_mm()).

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/sysrq.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index a1bcad7ef739..8db9125133b8 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -324,9 +324,12 @@ static void send_sig_all(int sig)
 
 	read_lock(&tasklist_lock);
 	for_each_process(p) {
-		if (p->mm && !is_global_init(p))
-			/* Not swapper, init nor kernel thread */
-			force_sig(sig, p);
+		if (p->flags & PF_KTHREAD)
+			continue;
+		if (is_global_init(p))
+			continue;
+
+		force_sig(sig, p);
 	}
 	read_unlock(&tasklist_lock);
 }

From 3f5dc70721af68b76ad544b0c61fea365d67c041 Mon Sep 17 00:00:00 2001
From: Tobias Klauser <tklauser@distanz.ch>
Date: Wed, 8 Feb 2012 14:35:46 +0100
Subject: [PATCH 19/20] tty: serial: altera_uart: remove
 early_altera_uart_setup

The function has no users inside the tree and the nios2
(out-of-mainline) port doesn't use it either (anymore).

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/altera_uart.c | 23 -----------------------
 include/linux/altera_uart.h      |  4 ----
 2 files changed, 27 deletions(-)

diff --git a/drivers/tty/serial/altera_uart.c b/drivers/tty/serial/altera_uart.c
index 1d04c5037f25..217833e94b5b 100644
--- a/drivers/tty/serial/altera_uart.c
+++ b/drivers/tty/serial/altera_uart.c
@@ -403,29 +403,6 @@ static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
 
 #if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
 
-int __init early_altera_uart_setup(struct altera_uart_platform_uart *platp)
-{
-	struct uart_port *port;
-	int i;
-
-	for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS && platp[i].mapbase; i++) {
-		port = &altera_uart_ports[i].port;
-
-		port->line = i;
-		port->type = PORT_ALTERA_UART;
-		port->mapbase = platp[i].mapbase;
-		port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
-		port->iotype = SERIAL_IO_MEM;
-		port->irq = platp[i].irq;
-		port->uartclk = platp[i].uartclk;
-		port->flags = UPF_BOOT_AUTOCONF;
-		port->ops = &altera_uart_ops;
-		port->private_data = platp;
-	}
-
-	return 0;
-}
-
 static void altera_uart_console_putc(struct uart_port *port, const char c)
 {
 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
diff --git a/include/linux/altera_uart.h b/include/linux/altera_uart.h
index a10a90791976..c022c82db7ca 100644
--- a/include/linux/altera_uart.h
+++ b/include/linux/altera_uart.h
@@ -5,8 +5,6 @@
 #ifndef	__ALTUART_H
 #define	__ALTUART_H
 
-#include <linux/init.h>
-
 struct altera_uart_platform_uart {
 	unsigned long mapbase;	/* Physical address base */
 	unsigned int irq;	/* Interrupt vector */
@@ -14,6 +12,4 @@ struct altera_uart_platform_uart {
 	unsigned int bus_shift;	/* Bus shift (address stride) */
 };
 
-int __init early_altera_uart_setup(struct altera_uart_platform_uart *platp);
-
 #endif /* __ALTUART_H */

From 418a936e84e8f346da322c2e839992aa9df108d4 Mon Sep 17 00:00:00 2001
From: Tobias Klauser <tklauser@distanz.ch>
Date: Wed, 8 Feb 2012 14:36:09 +0100
Subject: [PATCH 20/20] tty: serial: altera_uart: Add CONSOLE_POLL support

This allows altera_uart to be used for KGDB debugging over serial line.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/Makefile      |  2 +-
 drivers/tty/serial/altera_uart.c | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 1997ad4a39a6..50d279000e79 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -75,12 +75,12 @@ obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
 obj-$(CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL) += nwpserial.o
 obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
 obj-$(CONFIG_SERIAL_OMAP) += omap-serial.o
+obj-$(CONFIG_SERIAL_ALTERA_UART) += altera_uart.o
 obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
 obj-$(CONFIG_SERIAL_QE) += ucc_uart.o
 obj-$(CONFIG_SERIAL_TIMBERDALE)	+= timbuart.o
 obj-$(CONFIG_SERIAL_GRLIB_GAISLER_APBUART) += apbuart.o
 obj-$(CONFIG_SERIAL_ALTERA_JTAGUART) += altera_jtaguart.o
-obj-$(CONFIG_SERIAL_ALTERA_UART) += altera_uart.o
 obj-$(CONFIG_SERIAL_VT8500) += vt8500_serial.o
 obj-$(CONFIG_SERIAL_MRST_MAX3110)	+= mrst_max3110.o
 obj-$(CONFIG_SERIAL_MFD_HSU)	+= mfd.o
diff --git a/drivers/tty/serial/altera_uart.c b/drivers/tty/serial/altera_uart.c
index 217833e94b5b..e7903751e058 100644
--- a/drivers/tty/serial/altera_uart.c
+++ b/drivers/tty/serial/altera_uart.c
@@ -377,6 +377,26 @@ static int altera_uart_verify_port(struct uart_port *port,
 	return 0;
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+static int altera_uart_poll_get_char(struct uart_port *port)
+{
+	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
+		 ALTERA_UART_STATUS_RRDY_MSK))
+		cpu_relax();
+
+	return altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
+}
+
+static void altera_uart_poll_put_char(struct uart_port *port, unsigned char c)
+{
+	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
+		 ALTERA_UART_STATUS_TRDY_MSK))
+		cpu_relax();
+
+	altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
+}
+#endif
+
 /*
  *	Define the basic serial functions we support.
  */
@@ -397,6 +417,10 @@ static struct uart_ops altera_uart_ops = {
 	.release_port	= altera_uart_release_port,
 	.config_port	= altera_uart_config_port,
 	.verify_port	= altera_uart_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_get_char	= altera_uart_poll_get_char,
+	.poll_put_char	= altera_uart_poll_put_char,
+#endif
 };
 
 static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];