linux-sg2042/arch/mips/kernel/rtlx.c

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/*
* Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved.
* Copyright (C) 2005, 06 Ralf Baechle (ralf@linux-mips.org)
*
* This program is free software; you can distribute it and/or modify it
* under the terms of the GNU General Public License (Version 2) as
* published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
*
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <linux/list.h>
#include <linux/vmalloc.h>
#include <linux/elf.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/moduleloader.h>
#include <linux/interrupt.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <asm/mipsmtregs.h>
#include <asm/mips_mt.h>
#include <asm/cacheflush.h>
#include <linux/atomic.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/vpe.h>
#include <asm/rtlx.h>
static struct rtlx_info *rtlx;
static int major;
static char module_name[] = "rtlx";
static struct chan_waitqueues {
wait_queue_head_t rt_queue;
wait_queue_head_t lx_queue;
atomic_t in_open;
struct mutex mutex;
} channel_wqs[RTLX_CHANNELS];
static struct vpe_notifications notify;
static int sp_stopping;
extern void *vpe_get_shared(int index);
static void rtlx_dispatch(void)
{
do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ);
}
/* Interrupt handler may be called before rtlx_init has otherwise had
a chance to run.
*/
static irqreturn_t rtlx_interrupt(int irq, void *dev_id)
{
unsigned int vpeflags;
unsigned long flags;
int i;
/* Ought not to be strictly necessary for SMTC builds */
local_irq_save(flags);
vpeflags = dvpe();
set_c0_status(0x100 << MIPS_CPU_RTLX_IRQ);
irq_enable_hazard();
evpe(vpeflags);
local_irq_restore(flags);
for (i = 0; i < RTLX_CHANNELS; i++) {
wake_up(&channel_wqs[i].lx_queue);
wake_up(&channel_wqs[i].rt_queue);
}
return IRQ_HANDLED;
}
static void __used dump_rtlx(void)
{
int i;
printk("id 0x%lx state %d\n", rtlx->id, rtlx->state);
for (i = 0; i < RTLX_CHANNELS; i++) {
struct rtlx_channel *chan = &rtlx->channel[i];
printk(" rt_state %d lx_state %d buffer_size %d\n",
chan->rt_state, chan->lx_state, chan->buffer_size);
printk(" rt_read %d rt_write %d\n",
chan->rt_read, chan->rt_write);
printk(" lx_read %d lx_write %d\n",
chan->lx_read, chan->lx_write);
printk(" rt_buffer <%s>\n", chan->rt_buffer);
printk(" lx_buffer <%s>\n", chan->lx_buffer);
}
}
/* call when we have the address of the shared structure from the SP side. */
static int rtlx_init(struct rtlx_info *rtlxi)
{
if (rtlxi->id != RTLX_ID) {
printk(KERN_ERR "no valid RTLX id at 0x%p 0x%lx\n",
rtlxi, rtlxi->id);
return -ENOEXEC;
}
rtlx = rtlxi;
return 0;
}
/* notifications */
static void starting(int vpe)
{
int i;
sp_stopping = 0;
/* force a reload of rtlx */
rtlx=NULL;
/* wake up any sleeping rtlx_open's */
for (i = 0; i < RTLX_CHANNELS; i++)
wake_up_interruptible(&channel_wqs[i].lx_queue);
}
static void stopping(int vpe)
{
int i;
sp_stopping = 1;
for (i = 0; i < RTLX_CHANNELS; i++)
wake_up_interruptible(&channel_wqs[i].lx_queue);
}
int rtlx_open(int index, int can_sleep)
{
struct rtlx_info **p;
struct rtlx_channel *chan;
enum rtlx_state state;
int ret = 0;
if (index >= RTLX_CHANNELS) {
printk(KERN_DEBUG "rtlx_open index out of range\n");
return -ENOSYS;
}
if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {
printk(KERN_DEBUG "rtlx_open channel %d already opened\n",
index);
ret = -EBUSY;
goto out_fail;
}
if (rtlx == NULL) {
if( (p = vpe_get_shared(tclimit)) == NULL) {
if (can_sleep) {
__wait_event_interruptible(channel_wqs[index].lx_queue,
(p = vpe_get_shared(tclimit)), ret);
if (ret)
goto out_fail;
} else {
printk(KERN_DEBUG "No SP program loaded, and device "
"opened with O_NONBLOCK\n");
ret = -ENOSYS;
goto out_fail;
}
}
smp_rmb();
if (*p == NULL) {
if (can_sleep) {
DEFINE_WAIT(wait);
for (;;) {
prepare_to_wait(
&channel_wqs[index].lx_queue,
&wait, TASK_INTERRUPTIBLE);
smp_rmb();
if (*p != NULL)
break;
if (!signal_pending(current)) {
schedule();
continue;
}
ret = -ERESTARTSYS;
goto out_fail;
}
finish_wait(&channel_wqs[index].lx_queue, &wait);
} else {
pr_err(" *vpe_get_shared is NULL. "
"Has an SP program been loaded?\n");
ret = -ENOSYS;
goto out_fail;
}
}
if ((unsigned int)*p < KSEG0) {
printk(KERN_WARNING "vpe_get_shared returned an "
"invalid pointer maybe an error code %d\n",
(int)*p);
ret = -ENOSYS;
goto out_fail;
}
if ((ret = rtlx_init(*p)) < 0)
goto out_ret;
}
chan = &rtlx->channel[index];
state = xchg(&chan->lx_state, RTLX_STATE_OPENED);
if (state == RTLX_STATE_OPENED) {
ret = -EBUSY;
goto out_fail;
}
out_fail:
smp_mb();
atomic_dec(&channel_wqs[index].in_open);
smp_mb();
out_ret:
return ret;
}
int rtlx_release(int index)
{
if (rtlx == NULL) {
pr_err("rtlx_release() with null rtlx\n");
return 0;
}
rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;
return 0;
}
unsigned int rtlx_read_poll(int index, int can_sleep)
{
struct rtlx_channel *chan;
if (rtlx == NULL)
return 0;
chan = &rtlx->channel[index];
/* data available to read? */
if (chan->lx_read == chan->lx_write) {
if (can_sleep) {
int ret = 0;
__wait_event_interruptible(channel_wqs[index].lx_queue,
(chan->lx_read != chan->lx_write) ||
sp_stopping, ret);
if (ret)
return ret;
if (sp_stopping)
return 0;
} else
return 0;
}
return (chan->lx_write + chan->buffer_size - chan->lx_read)
% chan->buffer_size;
}
static inline int write_spacefree(int read, int write, int size)
{
if (read == write) {
/*
* Never fill the buffer completely, so indexes are always
* equal if empty and only empty, or !equal if data available
*/
return size - 1;
}
return ((read + size - write) % size) - 1;
}
unsigned int rtlx_write_poll(int index)
{
struct rtlx_channel *chan = &rtlx->channel[index];
return write_spacefree(chan->rt_read, chan->rt_write,
chan->buffer_size);
}
ssize_t rtlx_read(int index, void __user *buff, size_t count)
{
size_t lx_write, fl = 0L;
struct rtlx_channel *lx;
unsigned long failed;
if (rtlx == NULL)
return -ENOSYS;
lx = &rtlx->channel[index];
mutex_lock(&channel_wqs[index].mutex);
smp_rmb();
lx_write = lx->lx_write;
/* find out how much in total */
count = min(count,
(size_t)(lx_write + lx->buffer_size - lx->lx_read)
% lx->buffer_size);
/* then how much from the read pointer onwards */
fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
if (failed)
goto out;
/* and if there is anything left at the beginning of the buffer */
if (count - fl)
failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);
out:
count -= failed;
smp_wmb();
lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
smp_wmb();
mutex_unlock(&channel_wqs[index].mutex);
return count;
}
ssize_t rtlx_write(int index, const void __user *buffer, size_t count)
{
struct rtlx_channel *rt;
unsigned long failed;
size_t rt_read;
size_t fl;
if (rtlx == NULL)
return(-ENOSYS);
rt = &rtlx->channel[index];
mutex_lock(&channel_wqs[index].mutex);
smp_rmb();
rt_read = rt->rt_read;
/* total number of bytes to copy */
count = min(count, (size_t)write_spacefree(rt_read, rt->rt_write,
rt->buffer_size));
/* first bit from write pointer to the end of the buffer, or count */
fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
if (failed)
goto out;
/* if there's any left copy to the beginning of the buffer */
if (count - fl) {
failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
}
out:
count -= failed;
smp_wmb();
rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
smp_wmb();
mutex_unlock(&channel_wqs[index].mutex);
return count;
}
static int file_open(struct inode *inode, struct file *filp)
{
return rtlx_open(iminor(inode), (filp->f_flags & O_NONBLOCK) ? 0 : 1);
}
static int file_release(struct inode *inode, struct file *filp)
{
return rtlx_release(iminor(inode));
}
static unsigned int file_poll(struct file *file, poll_table * wait)
{
int minor;
unsigned int mask = 0;
minor = iminor(file->f_path.dentry->d_inode);
poll_wait(file, &channel_wqs[minor].rt_queue, wait);
poll_wait(file, &channel_wqs[minor].lx_queue, wait);
if (rtlx == NULL)
return 0;
/* data available to read? */
if (rtlx_read_poll(minor, 0))
mask |= POLLIN | POLLRDNORM;
/* space to write */
if (rtlx_write_poll(minor))
mask |= POLLOUT | POLLWRNORM;
return mask;
}
static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
loff_t * ppos)
{
int minor = iminor(file->f_path.dentry->d_inode);
/* data available? */
if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) {
return 0; // -EAGAIN makes cat whinge
}
return rtlx_read(minor, buffer, count);
}
static ssize_t file_write(struct file *file, const char __user * buffer,
size_t count, loff_t * ppos)
{
int minor;
struct rtlx_channel *rt;
minor = iminor(file->f_path.dentry->d_inode);
rt = &rtlx->channel[minor];
/* any space left... */
if (!rtlx_write_poll(minor)) {
int ret = 0;
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
__wait_event_interruptible(channel_wqs[minor].rt_queue,
rtlx_write_poll(minor),
ret);
if (ret)
return ret;
}
return rtlx_write(minor, buffer, count);
}
static const struct file_operations rtlx_fops = {
.owner = THIS_MODULE,
.open = file_open,
.release = file_release,
.write = file_write,
.read = file_read,
llseek: automatically add .llseek fop All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
2010-08-16 00:52:59 +08:00
.poll = file_poll,
.llseek = noop_llseek,
};
static struct irqaction rtlx_irq = {
.handler = rtlx_interrupt,
.flags = IRQF_DISABLED,
.name = "RTLX",
};
static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
static char register_chrdev_failed[] __initdata =
KERN_ERR "rtlx_module_init: unable to register device\n";
static int __init rtlx_module_init(void)
{
struct device *dev;
int i, err;
if (!cpu_has_mipsmt) {
printk("VPE loader: not a MIPS MT capable processor\n");
return -ENODEV;
}
if (tclimit == 0) {
printk(KERN_WARNING "No TCs reserved for AP/SP, not "
"initializing RTLX.\nPass maxtcs=<n> argument as kernel "
"argument\n");
return -ENODEV;
}
major = register_chrdev(0, module_name, &rtlx_fops);
if (major < 0) {
printk(register_chrdev_failed);
return major;
}
/* initialise the wait queues */
for (i = 0; i < RTLX_CHANNELS; i++) {
init_waitqueue_head(&channel_wqs[i].rt_queue);
init_waitqueue_head(&channel_wqs[i].lx_queue);
atomic_set(&channel_wqs[i].in_open, 0);
mutex_init(&channel_wqs[i].mutex);
dev = device_create(mt_class, NULL, MKDEV(major, i), NULL,
"%s%d", module_name, i);
if (IS_ERR(dev)) {
err = PTR_ERR(dev);
goto out_chrdev;
}
}
/* set up notifiers */
notify.start = starting;
notify.stop = stopping;
vpe_notify(tclimit, &notify);
if (cpu_has_vint)
set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
else {
pr_err("APRP RTLX init on non-vectored-interrupt processor\n");
err = -ENODEV;
goto out_chrdev;
}
rtlx_irq.dev_id = rtlx;
setup_irq(rtlx_irq_num, &rtlx_irq);
return 0;
out_chrdev:
for (i = 0; i < RTLX_CHANNELS; i++)
device_destroy(mt_class, MKDEV(major, i));
return err;
}
static void __exit rtlx_module_exit(void)
{
int i;
for (i = 0; i < RTLX_CHANNELS; i++)
device_destroy(mt_class, MKDEV(major, i));
unregister_chrdev(major, module_name);
}
module_init(rtlx_module_init);
module_exit(rtlx_module_exit);
MODULE_DESCRIPTION("MIPS RTLX");
MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
MODULE_LICENSE("GPL");