OpenCloudOS-Kernel/drivers/s390/char/sclp_vt220.c

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/*
* SCLP VT220 terminal driver.
*
* Copyright IBM Corp. 2003, 2009
*
* Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
*/
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/timer.h>
#include <linux/kernel.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
[PATCH] TTY layer buffering revamp The API and code have been through various bits of initial review by serial driver people but they definitely need to live somewhere for a while so the unconverted drivers can get knocked into shape, existing drivers that have been updated can be better tuned and bugs whacked out. This replaces the tty flip buffers with kmalloc objects in rings. In the normal situation for an IRQ driven serial port at typical speeds the behaviour is pretty much the same, two buffers end up allocated and the kernel cycles between them as before. When there are delays or at high speed we now behave far better as the buffer pool can grow a bit rather than lose characters. This also means that we can operate at higher speeds reliably. For drivers that receive characters in blocks (DMA based, USB and especially virtualisation) the layer allows a lot of driver specific code that works around the tty layer with private secondary queues to be removed. The IBM folks need this sort of layer, the smart serial port people do, the virtualisers do (because a virtualised tty typically operates at infinite speed rather than emulating 9600 baud). Finally many drivers had invalid and unsafe attempts to avoid buffer overflows by directly invoking tty methods extracted out of the innards of work queue structs. These are no longer needed and all go away. That fixes various random hangs with serial ports on overflow. The other change in here is to optimise the receive_room path that is used by some callers. It turns out that only one ldisc uses receive room except asa constant and it updates it far far less than the value is read. We thus make it a variable not a function call. I expect the code to contain bugs due to the size alone but I'll be watching and squashing them and feeding out new patches as it goes. Because the buffers now dynamically expand you should only run out of buffering when the kernel runs out of memory for real. That means a lot of the horrible hacks high performance drivers used to do just aren't needed any more. Description: tty_insert_flip_char is an old API and continues to work as before, as does tty_flip_buffer_push() [this is why many drivers dont need modification]. It does now also return the number of chars inserted There are also tty_buffer_request_room(tty, len) which asks for a buffer block of the length requested and returns the space found. This improves efficiency with hardware that knows how much to transfer. and tty_insert_flip_string_flags(tty, str, flags, len) to insert a string of characters and flags For a smart interface the usual code is len = tty_request_buffer_room(tty, amount_hardware_says); tty_insert_flip_string(tty, buffer_from_card, len); More description! At the moment tty buffers are attached directly to the tty. This is causing a lot of the problems related to tty layer locking, also problems at high speed and also with bursty data (such as occurs in virtualised environments) I'm working on ripping out the flip buffers and replacing them with a pool of dynamically allocated buffers. This allows both for old style "byte I/O" devices and also helps virtualisation and smart devices where large blocks of data suddenely materialise and need storing. So far so good. Lots of drivers reference tty->flip.*. Several of them also call directly and unsafely into function pointers it provides. This will all break. Most drivers can use tty_insert_flip_char which can be kept as an API but others need more. At the moment I've added the following interfaces, if people think more will be needed now is a good time to say int tty_buffer_request_room(tty, size) Try and ensure at least size bytes are available, returns actual room (may be zero). At the moment it just uses the flipbuf space but that will change. Repeated calls without characters being added are not cumulative. (ie if you call it with 1, 1, 1, and then 4 you'll have four characters of space. The other functions will also try and grow buffers in future but this will be a more efficient way when you know block sizes. int tty_insert_flip_char(tty, ch, flag) As before insert a character if there is room. Now returns 1 for success, 0 for failure. int tty_insert_flip_string(tty, str, len) Insert a block of non error characters. Returns the number inserted. int tty_prepare_flip_string(tty, strptr, len) Adjust the buffer to allow len characters to be added. Returns a buffer pointer in strptr and the length available. This allows for hardware that needs to use functions like insl or mencpy_fromio. Signed-off-by: Alan Cox <alan@redhat.com> Cc: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: John Hawkes <hawkes@sgi.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10 12:54:13 +08:00
#include <linux/tty_flip.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/major.h>
#include <linux/console.h>
#include <linux/kdev_t.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/reboot.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <asm/uaccess.h>
#include "sclp.h"
#define SCLP_VT220_MAJOR TTY_MAJOR
#define SCLP_VT220_MINOR 65
#define SCLP_VT220_DRIVER_NAME "sclp_vt220"
#define SCLP_VT220_DEVICE_NAME "ttysclp"
#define SCLP_VT220_CONSOLE_NAME "ttyS"
#define SCLP_VT220_CONSOLE_INDEX 1 /* console=ttyS1 */
/* Representation of a single write request */
struct sclp_vt220_request {
struct list_head list;
struct sclp_req sclp_req;
int retry_count;
};
/* VT220 SCCB */
struct sclp_vt220_sccb {
struct sccb_header header;
struct evbuf_header evbuf;
};
#define SCLP_VT220_MAX_CHARS_PER_BUFFER (PAGE_SIZE - \
sizeof(struct sclp_vt220_request) - \
sizeof(struct sclp_vt220_sccb))
/* Structures and data needed to register tty driver */
static struct tty_driver *sclp_vt220_driver;
static struct tty_port sclp_vt220_port;
/* Lock to protect internal data from concurrent access */
static spinlock_t sclp_vt220_lock;
/* List of empty pages to be used as write request buffers */
static struct list_head sclp_vt220_empty;
/* List of pending requests */
static struct list_head sclp_vt220_outqueue;
/* Suspend mode flag */
static int sclp_vt220_suspended;
/* Flag that output queue is currently running */
static int sclp_vt220_queue_running;
/* Timer used for delaying write requests to merge subsequent messages into
* a single buffer */
static struct timer_list sclp_vt220_timer;
/* Pointer to current request buffer which has been partially filled but not
* yet sent */
static struct sclp_vt220_request *sclp_vt220_current_request;
/* Number of characters in current request buffer */
static int sclp_vt220_buffered_chars;
/* Counter controlling core driver initialization. */
static int __initdata sclp_vt220_init_count;
/* Flag indicating that sclp_vt220_current_request should really
* have been already queued but wasn't because the SCLP was processing
* another buffer */
static int sclp_vt220_flush_later;
static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
enum sclp_pm_event sclp_pm_event);
static int __sclp_vt220_emit(struct sclp_vt220_request *request);
static void sclp_vt220_emit_current(void);
/* Registration structure for SCLP output event buffers */
static struct sclp_register sclp_vt220_register = {
.send_mask = EVTYP_VT220MSG_MASK,
.pm_event_fn = sclp_vt220_pm_event_fn,
};
/* Registration structure for SCLP input event buffers */
static struct sclp_register sclp_vt220_register_input = {
.receive_mask = EVTYP_VT220MSG_MASK,
.receiver_fn = sclp_vt220_receiver_fn,
};
/*
* Put provided request buffer back into queue and check emit pending
* buffers if necessary.
*/
static void
sclp_vt220_process_queue(struct sclp_vt220_request *request)
{
unsigned long flags;
void *page;
do {
/* Put buffer back to list of empty buffers */
page = request->sclp_req.sccb;
spin_lock_irqsave(&sclp_vt220_lock, flags);
/* Move request from outqueue to empty queue */
list_del(&request->list);
list_add_tail((struct list_head *) page, &sclp_vt220_empty);
/* Check if there is a pending buffer on the out queue. */
request = NULL;
if (!list_empty(&sclp_vt220_outqueue))
request = list_entry(sclp_vt220_outqueue.next,
struct sclp_vt220_request, list);
if (!request || sclp_vt220_suspended) {
sclp_vt220_queue_running = 0;
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
break;
}
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
} while (__sclp_vt220_emit(request));
if (request == NULL && sclp_vt220_flush_later)
sclp_vt220_emit_current();
tty_port_tty_wakeup(&sclp_vt220_port);
}
#define SCLP_BUFFER_MAX_RETRY 1
/*
* Callback through which the result of a write request is reported by the
* SCLP.
*/
static void
sclp_vt220_callback(struct sclp_req *request, void *data)
{
struct sclp_vt220_request *vt220_request;
struct sclp_vt220_sccb *sccb;
vt220_request = (struct sclp_vt220_request *) data;
if (request->status == SCLP_REQ_FAILED) {
sclp_vt220_process_queue(vt220_request);
return;
}
sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
/* Check SCLP response code and choose suitable action */
switch (sccb->header.response_code) {
case 0x0020 :
break;
case 0x05f0: /* Target resource in improper state */
break;
case 0x0340: /* Contained SCLP equipment check */
if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
break;
/* Remove processed buffers and requeue rest */
if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
/* Not all buffers were processed */
sccb->header.response_code = 0x0000;
vt220_request->sclp_req.status = SCLP_REQ_FILLED;
if (sclp_add_request(request) == 0)
return;
}
break;
case 0x0040: /* SCLP equipment check */
if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
break;
sccb->header.response_code = 0x0000;
vt220_request->sclp_req.status = SCLP_REQ_FILLED;
if (sclp_add_request(request) == 0)
return;
break;
default:
break;
}
sclp_vt220_process_queue(vt220_request);
}
/*
* Emit vt220 request buffer to SCLP. Return zero on success, non-zero
* otherwise.
*/
static int
__sclp_vt220_emit(struct sclp_vt220_request *request)
{
request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
request->sclp_req.status = SCLP_REQ_FILLED;
request->sclp_req.callback = sclp_vt220_callback;
request->sclp_req.callback_data = (void *) request;
return sclp_add_request(&request->sclp_req);
}
/*
* Queue and emit current request.
*/
static void
sclp_vt220_emit_current(void)
{
unsigned long flags;
struct sclp_vt220_request *request;
struct sclp_vt220_sccb *sccb;
spin_lock_irqsave(&sclp_vt220_lock, flags);
if (sclp_vt220_current_request) {
sccb = (struct sclp_vt220_sccb *)
sclp_vt220_current_request->sclp_req.sccb;
/* Only emit buffers with content */
if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
list_add_tail(&sclp_vt220_current_request->list,
&sclp_vt220_outqueue);
sclp_vt220_current_request = NULL;
if (timer_pending(&sclp_vt220_timer))
del_timer(&sclp_vt220_timer);
}
sclp_vt220_flush_later = 0;
}
if (sclp_vt220_queue_running || sclp_vt220_suspended)
goto out_unlock;
if (list_empty(&sclp_vt220_outqueue))
goto out_unlock;
request = list_first_entry(&sclp_vt220_outqueue,
struct sclp_vt220_request, list);
sclp_vt220_queue_running = 1;
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
if (__sclp_vt220_emit(request))
sclp_vt220_process_queue(request);
return;
out_unlock:
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
}
#define SCLP_NORMAL_WRITE 0x00
/*
* Helper function to initialize a page with the sclp request structure.
*/
static struct sclp_vt220_request *
sclp_vt220_initialize_page(void *page)
{
struct sclp_vt220_request *request;
struct sclp_vt220_sccb *sccb;
/* Place request structure at end of page */
request = ((struct sclp_vt220_request *)
((addr_t) page + PAGE_SIZE)) - 1;
request->retry_count = 0;
request->sclp_req.sccb = page;
/* SCCB goes at start of page */
sccb = (struct sclp_vt220_sccb *) page;
memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
sccb->header.length = sizeof(struct sclp_vt220_sccb);
sccb->header.function_code = SCLP_NORMAL_WRITE;
sccb->header.response_code = 0x0000;
sccb->evbuf.type = EVTYP_VT220MSG;
sccb->evbuf.length = sizeof(struct evbuf_header);
return request;
}
static inline unsigned int
sclp_vt220_space_left(struct sclp_vt220_request *request)
{
struct sclp_vt220_sccb *sccb;
sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
sccb->header.length;
}
static inline unsigned int
sclp_vt220_chars_stored(struct sclp_vt220_request *request)
{
struct sclp_vt220_sccb *sccb;
sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
return sccb->evbuf.length - sizeof(struct evbuf_header);
}
/*
* Add msg to buffer associated with request. Return the number of characters
* added.
*/
static int
sclp_vt220_add_msg(struct sclp_vt220_request *request,
const unsigned char *msg, int count, int convertlf)
{
struct sclp_vt220_sccb *sccb;
void *buffer;
unsigned char c;
int from;
int to;
if (count > sclp_vt220_space_left(request))
count = sclp_vt220_space_left(request);
if (count <= 0)
return 0;
sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
buffer = (void *) ((addr_t) sccb + sccb->header.length);
if (convertlf) {
/* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
for (from=0, to=0;
(from < count) && (to < sclp_vt220_space_left(request));
from++) {
/* Retrieve character */
c = msg[from];
/* Perform conversion */
if (c == 0x0a) {
if (to + 1 < sclp_vt220_space_left(request)) {
((unsigned char *) buffer)[to++] = c;
((unsigned char *) buffer)[to++] = 0x0d;
} else
break;
} else
((unsigned char *) buffer)[to++] = c;
}
sccb->header.length += to;
sccb->evbuf.length += to;
return from;
} else {
memcpy(buffer, (const void *) msg, count);
sccb->header.length += count;
sccb->evbuf.length += count;
return count;
}
}
/*
* Emit buffer after having waited long enough for more data to arrive.
*/
static void
sclp_vt220_timeout(unsigned long data)
{
sclp_vt220_emit_current();
}
#define BUFFER_MAX_DELAY HZ/20
/*
* Drop oldest console buffer if sclp_con_drop is set
*/
static int
sclp_vt220_drop_buffer(void)
{
struct list_head *list;
struct sclp_vt220_request *request;
void *page;
if (!sclp_console_drop)
return 0;
list = sclp_vt220_outqueue.next;
if (sclp_vt220_queue_running)
/* The first element is in I/O */
list = list->next;
if (list == &sclp_vt220_outqueue)
return 0;
list_del(list);
request = list_entry(list, struct sclp_vt220_request, list);
page = request->sclp_req.sccb;
list_add_tail((struct list_head *) page, &sclp_vt220_empty);
return 1;
}
/*
* Internal implementation of the write function. Write COUNT bytes of data
* from memory at BUF
* to the SCLP interface. In case that the data does not fit into the current
* write buffer, emit the current one and allocate a new one. If there are no
* more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
* is non-zero, the buffer will be scheduled for emitting after a timeout -
* otherwise the user has to explicitly call the flush function.
* A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
* buffer should be converted to 0x0a 0x0d. After completion, return the number
* of bytes written.
*/
static int
__sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
int convertlf, int may_fail)
{
unsigned long flags;
void *page;
int written;
int overall_written;
if (count <= 0)
return 0;
overall_written = 0;
spin_lock_irqsave(&sclp_vt220_lock, flags);
do {
/* Create an sclp output buffer if none exists yet */
if (sclp_vt220_current_request == NULL) {
if (list_empty(&sclp_vt220_empty))
sclp_console_full++;
while (list_empty(&sclp_vt220_empty)) {
if (may_fail || sclp_vt220_suspended)
goto out;
if (sclp_vt220_drop_buffer())
break;
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
sclp_sync_wait();
spin_lock_irqsave(&sclp_vt220_lock, flags);
}
page = (void *) sclp_vt220_empty.next;
list_del((struct list_head *) page);
sclp_vt220_current_request =
sclp_vt220_initialize_page(page);
}
/* Try to write the string to the current request buffer */
written = sclp_vt220_add_msg(sclp_vt220_current_request,
buf, count, convertlf);
overall_written += written;
if (written == count)
break;
/*
* Not all characters could be written to the current
* output buffer. Emit the buffer, create a new buffer
* and then output the rest of the string.
*/
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
sclp_vt220_emit_current();
spin_lock_irqsave(&sclp_vt220_lock, flags);
buf += written;
count -= written;
} while (count > 0);
/* Setup timer to output current console buffer after some time */
if (sclp_vt220_current_request != NULL &&
!timer_pending(&sclp_vt220_timer) && do_schedule) {
sclp_vt220_timer.function = sclp_vt220_timeout;
sclp_vt220_timer.data = 0UL;
sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
add_timer(&sclp_vt220_timer);
}
out:
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
return overall_written;
}
/*
* This routine is called by the kernel to write a series of
* characters to the tty device. The characters may come from
* user space or kernel space. This routine will return the
* number of characters actually accepted for writing.
*/
static int
sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
return __sclp_vt220_write(buf, count, 1, 0, 1);
}
#define SCLP_VT220_SESSION_ENDED 0x01
#define SCLP_VT220_SESSION_STARTED 0x80
#define SCLP_VT220_SESSION_DATA 0x00
/*
* Called by the SCLP to report incoming event buffers.
*/
static void
sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
{
char *buffer;
unsigned int count;
buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
count = evbuf->length - sizeof(struct evbuf_header);
switch (*buffer) {
case SCLP_VT220_SESSION_ENDED:
case SCLP_VT220_SESSION_STARTED:
break;
case SCLP_VT220_SESSION_DATA:
/* Send input to line discipline */
buffer++;
count--;
tty_insert_flip_string(&sclp_vt220_port, buffer, count);
tty_flip_buffer_push(&sclp_vt220_port);
break;
}
}
/*
* This routine is called when a particular tty device is opened.
*/
static int
sclp_vt220_open(struct tty_struct *tty, struct file *filp)
{
if (tty->count == 1) {
tty_port_tty_set(&sclp_vt220_port, tty);
sclp_vt220_port.low_latency = 0;
if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
tty->winsize.ws_row = 24;
tty->winsize.ws_col = 80;
}
}
return 0;
}
/*
* This routine is called when a particular tty device is closed.
*/
static void
sclp_vt220_close(struct tty_struct *tty, struct file *filp)
{
if (tty->count == 1)
tty_port_tty_set(&sclp_vt220_port, NULL);
}
/*
* This routine is called by the kernel to write a single
* character to the tty device. If the kernel uses this routine,
* it must call the flush_chars() routine (if defined) when it is
* done stuffing characters into the driver.
*/
static int
sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
{
return __sclp_vt220_write(&ch, 1, 0, 0, 1);
}
/*
* This routine is called by the kernel after it has written a
* series of characters to the tty device using put_char().
*/
static void
sclp_vt220_flush_chars(struct tty_struct *tty)
{
if (!sclp_vt220_queue_running)
sclp_vt220_emit_current();
else
sclp_vt220_flush_later = 1;
}
/*
* This routine returns the numbers of characters the tty driver
* will accept for queuing to be written. This number is subject
* to change as output buffers get emptied, or if the output flow
* control is acted.
*/
static int
sclp_vt220_write_room(struct tty_struct *tty)
{
unsigned long flags;
struct list_head *l;
int count;
spin_lock_irqsave(&sclp_vt220_lock, flags);
count = 0;
if (sclp_vt220_current_request != NULL)
count = sclp_vt220_space_left(sclp_vt220_current_request);
list_for_each(l, &sclp_vt220_empty)
count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
return count;
}
/*
* Return number of buffered chars.
*/
static int
sclp_vt220_chars_in_buffer(struct tty_struct *tty)
{
unsigned long flags;
struct list_head *l;
struct sclp_vt220_request *r;
int count;
spin_lock_irqsave(&sclp_vt220_lock, flags);
count = 0;
if (sclp_vt220_current_request != NULL)
count = sclp_vt220_chars_stored(sclp_vt220_current_request);
list_for_each(l, &sclp_vt220_outqueue) {
r = list_entry(l, struct sclp_vt220_request, list);
count += sclp_vt220_chars_stored(r);
}
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
return count;
}
/*
* Pass on all buffers to the hardware. Return only when there are no more
* buffers pending.
*/
static void
sclp_vt220_flush_buffer(struct tty_struct *tty)
{
sclp_vt220_emit_current();
}
/* Release allocated pages. */
static void __init __sclp_vt220_free_pages(void)
{
struct list_head *page, *p;
list_for_each_safe(page, p, &sclp_vt220_empty) {
list_del(page);
free_page((unsigned long) page);
}
}
/* Release memory and unregister from sclp core. Controlled by init counting -
* only the last invoker will actually perform these actions. */
static void __init __sclp_vt220_cleanup(void)
{
sclp_vt220_init_count--;
if (sclp_vt220_init_count != 0)
return;
sclp_unregister(&sclp_vt220_register);
__sclp_vt220_free_pages();
tty_port_destroy(&sclp_vt220_port);
}
/* Allocate buffer pages and register with sclp core. Controlled by init
* counting - only the first invoker will actually perform these actions. */
static int __init __sclp_vt220_init(int num_pages)
{
void *page;
int i;
int rc;
sclp_vt220_init_count++;
if (sclp_vt220_init_count != 1)
return 0;
spin_lock_init(&sclp_vt220_lock);
INIT_LIST_HEAD(&sclp_vt220_empty);
INIT_LIST_HEAD(&sclp_vt220_outqueue);
init_timer(&sclp_vt220_timer);
tty_port_init(&sclp_vt220_port);
sclp_vt220_current_request = NULL;
sclp_vt220_buffered_chars = 0;
sclp_vt220_flush_later = 0;
/* Allocate pages for output buffering */
rc = -ENOMEM;
for (i = 0; i < num_pages; i++) {
page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
if (!page)
goto out;
list_add_tail(page, &sclp_vt220_empty);
}
rc = sclp_register(&sclp_vt220_register);
out:
if (rc) {
__sclp_vt220_free_pages();
sclp_vt220_init_count--;
tty_port_destroy(&sclp_vt220_port);
}
return rc;
}
static const struct tty_operations sclp_vt220_ops = {
.open = sclp_vt220_open,
.close = sclp_vt220_close,
.write = sclp_vt220_write,
.put_char = sclp_vt220_put_char,
.flush_chars = sclp_vt220_flush_chars,
.write_room = sclp_vt220_write_room,
.chars_in_buffer = sclp_vt220_chars_in_buffer,
.flush_buffer = sclp_vt220_flush_buffer,
};
/*
* Register driver with SCLP and Linux and initialize internal tty structures.
*/
static int __init sclp_vt220_tty_init(void)
{
struct tty_driver *driver;
int rc;
/* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
* symmetry between VM and LPAR systems regarding ttyS1. */
driver = alloc_tty_driver(1);
if (!driver)
return -ENOMEM;
rc = __sclp_vt220_init(MAX_KMEM_PAGES);
if (rc)
goto out_driver;
driver->driver_name = SCLP_VT220_DRIVER_NAME;
driver->name = SCLP_VT220_DEVICE_NAME;
driver->major = SCLP_VT220_MAJOR;
driver->minor_start = SCLP_VT220_MINOR;
driver->type = TTY_DRIVER_TYPE_SYSTEM;
driver->subtype = SYSTEM_TYPE_TTY;
driver->init_termios = tty_std_termios;
driver->flags = TTY_DRIVER_REAL_RAW;
tty_set_operations(driver, &sclp_vt220_ops);
tty_port_link_device(&sclp_vt220_port, driver, 0);
rc = tty_register_driver(driver);
if (rc)
goto out_init;
rc = sclp_register(&sclp_vt220_register_input);
if (rc)
goto out_reg;
sclp_vt220_driver = driver;
return 0;
out_reg:
tty_unregister_driver(driver);
out_init:
__sclp_vt220_cleanup();
out_driver:
put_tty_driver(driver);
return rc;
}
__initcall(sclp_vt220_tty_init);
static void __sclp_vt220_flush_buffer(void)
{
unsigned long flags;
sclp_vt220_emit_current();
spin_lock_irqsave(&sclp_vt220_lock, flags);
if (timer_pending(&sclp_vt220_timer))
del_timer(&sclp_vt220_timer);
while (sclp_vt220_queue_running) {
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
sclp_sync_wait();
spin_lock_irqsave(&sclp_vt220_lock, flags);
}
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
}
/*
* Resume console: If there are cached messages, emit them.
*/
static void sclp_vt220_resume(void)
{
unsigned long flags;
spin_lock_irqsave(&sclp_vt220_lock, flags);
sclp_vt220_suspended = 0;
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
sclp_vt220_emit_current();
}
/*
* Suspend console: Set suspend flag and flush console
*/
static void sclp_vt220_suspend(void)
{
unsigned long flags;
spin_lock_irqsave(&sclp_vt220_lock, flags);
sclp_vt220_suspended = 1;
spin_unlock_irqrestore(&sclp_vt220_lock, flags);
__sclp_vt220_flush_buffer();
}
static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
enum sclp_pm_event sclp_pm_event)
{
switch (sclp_pm_event) {
case SCLP_PM_EVENT_FREEZE:
sclp_vt220_suspend();
break;
case SCLP_PM_EVENT_RESTORE:
case SCLP_PM_EVENT_THAW:
sclp_vt220_resume();
break;
}
}
#ifdef CONFIG_SCLP_VT220_CONSOLE
static void
sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
{
__sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
}
static struct tty_driver *
sclp_vt220_con_device(struct console *c, int *index)
{
*index = 0;
return sclp_vt220_driver;
}
static int
sclp_vt220_notify(struct notifier_block *self,
unsigned long event, void *data)
{
__sclp_vt220_flush_buffer();
return NOTIFY_OK;
}
static struct notifier_block on_panic_nb = {
.notifier_call = sclp_vt220_notify,
.priority = 1,
};
static struct notifier_block on_reboot_nb = {
.notifier_call = sclp_vt220_notify,
.priority = 1,
};
/* Structure needed to register with printk */
static struct console sclp_vt220_console =
{
.name = SCLP_VT220_CONSOLE_NAME,
.write = sclp_vt220_con_write,
.device = sclp_vt220_con_device,
.flags = CON_PRINTBUFFER,
.index = SCLP_VT220_CONSOLE_INDEX
};
static int __init
sclp_vt220_con_init(void)
{
int rc;
rc = __sclp_vt220_init(sclp_console_pages);
if (rc)
return rc;
/* Attach linux console */
atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
register_reboot_notifier(&on_reboot_nb);
register_console(&sclp_vt220_console);
return 0;
}
console_initcall(sclp_vt220_con_init);
#endif /* CONFIG_SCLP_VT220_CONSOLE */