linux/arch/mips/kernel/rtlx.c
Arjan van de Ven 5dfe4c964a [PATCH] mark struct file_operations const 2
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

[akpm@osdl.org: sparc64 fix]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:44 -08:00

562 lines
13 KiB
C

/*
* 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/module.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <linux/slab.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 <asm/atomic.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/vpe.h>
#include <asm/rtlx.h>
#define RTLX_TARG_VPE 1
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;
int in_open;
} channel_wqs[RTLX_CHANNELS];
static struct irqaction irq;
static int irq_num;
static struct vpe_notifications notify;
static int sp_stopping = 0;
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)
{
int i;
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 __attribute_used__ void 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%x\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)
{
int ret;
struct rtlx_channel *chan;
volatile struct rtlx_info **p;
if (index >= RTLX_CHANNELS) {
printk(KERN_DEBUG "rtlx_open index out of range\n");
return -ENOSYS;
}
if (channel_wqs[index].in_open) {
printk(KERN_DEBUG "rtlx_open channel %d already opened\n", index);
return -EBUSY;
}
channel_wqs[index].in_open++;
if (rtlx == NULL) {
if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
if (can_sleep) {
DECLARE_WAITQUEUE(wait, current);
/* go to sleep */
add_wait_queue(&channel_wqs[index].lx_queue, &wait);
set_current_state(TASK_INTERRUPTIBLE);
while ((p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
schedule();
set_current_state(TASK_INTERRUPTIBLE);
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
/* back running */
} else {
printk( KERN_DEBUG "No SP program loaded, and device "
"opened with O_NONBLOCK\n");
channel_wqs[index].in_open = 0;
return -ENOSYS;
}
}
if (*p == NULL) {
if (can_sleep) {
DECLARE_WAITQUEUE(wait, current);
/* go to sleep */
add_wait_queue(&channel_wqs[index].lx_queue, &wait);
set_current_state(TASK_INTERRUPTIBLE);
while (*p == NULL) {
schedule();
/* reset task state to interruptable otherwise
we'll whizz round here like a very fast loopy
thing. schedule() appears to return with state
set to TASK_RUNNING.
If the loaded SP program, for whatever reason,
doesn't set up the shared structure *p will never
become true. So whoever connected to either /dev/rt?
or if it was kspd, will then take up rather a lot of
processor cycles.
*/
set_current_state(TASK_INTERRUPTIBLE);
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
/* back running */
}
else {
printk(" *vpe_get_shared is NULL. "
"Has an SP program been loaded?\n");
channel_wqs[index].in_open = 0;
return -ENOSYS;
}
}
if ((unsigned int)*p < KSEG0) {
printk(KERN_WARNING "vpe_get_shared returned an invalid pointer "
"maybe an error code %d\n", (int)*p);
channel_wqs[index].in_open = 0;
return -ENOSYS;
}
if ((ret = rtlx_init(*p)) < 0) {
channel_wqs[index].in_open = 0;
return ret;
}
}
chan = &rtlx->channel[index];
if (chan->lx_state == RTLX_STATE_OPENED) {
channel_wqs[index].in_open = 0;
return -EBUSY;
}
chan->lx_state = RTLX_STATE_OPENED;
channel_wqs[index].in_open = 0;
return 0;
}
int rtlx_release(int index)
{
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) {
DECLARE_WAITQUEUE(wait, current);
/* go to sleep */
add_wait_queue(&channel_wqs[index].lx_queue, &wait);
set_current_state(TASK_INTERRUPTIBLE);
while (chan->lx_read == chan->lx_write) {
schedule();
set_current_state(TASK_INTERRUPTIBLE);
if (sp_stopping) {
set_current_state(TASK_RUNNING);
remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
return 0;
}
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
/* back running */
}
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);
}
static inline void copy_to(void *dst, void *src, size_t count, int user)
{
if (user)
copy_to_user(dst, src, count);
else
memcpy(dst, src, count);
}
static inline void copy_from(void *dst, void *src, size_t count, int user)
{
if (user)
copy_from_user(dst, src, count);
else
memcpy(dst, src, count);
}
ssize_t rtlx_read(int index, void *buff, size_t count, int user)
{
size_t fl = 0L;
struct rtlx_channel *lx;
if (rtlx == NULL)
return -ENOSYS;
lx = &rtlx->channel[index];
/* find out how much in total */
count = min(count,
(size_t)(lx->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);
copy_to(buff, &lx->lx_buffer[lx->lx_read], fl, user);
/* and if there is anything left at the beginning of the buffer */
if ( count - fl )
copy_to (buff + fl, lx->lx_buffer, count - fl, user);
/* update the index */
lx->lx_read += count;
lx->lx_read %= lx->buffer_size;
return count;
}
ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
{
struct rtlx_channel *rt;
size_t fl;
if (rtlx == NULL)
return(-ENOSYS);
rt = &rtlx->channel[index];
/* total number of bytes to copy */
count = min(count,
(size_t)write_spacefree(rt->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);
copy_from (&rt->rt_buffer[rt->rt_write], buffer, fl, user);
/* if there's any left copy to the beginning of the buffer */
if( count - fl )
copy_from (rt->rt_buffer, buffer + fl, count - fl, user);
rt->rt_write += count;
rt->rt_write %= rt->buffer_size;
return(count);
}
static int file_open(struct inode *inode, struct file *filp)
{
int minor = iminor(inode);
return rtlx_open(minor, (filp->f_flags & O_NONBLOCK) ? 0 : 1);
}
static int file_release(struct inode *inode, struct file *filp)
{
int minor = iminor(inode);
return rtlx_release(minor);
}
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, 1);
}
static ssize_t file_write(struct file *file, const char __user * buffer,
size_t count, loff_t * ppos)
{
int minor;
struct rtlx_channel *rt;
DECLARE_WAITQUEUE(wait, current);
minor = iminor(file->f_path.dentry->d_inode);
rt = &rtlx->channel[minor];
/* any space left... */
if (!rtlx_write_poll(minor)) {
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
set_current_state(TASK_INTERRUPTIBLE);
while (!rtlx_write_poll(minor))
schedule();
set_current_state(TASK_RUNNING);
remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
}
return rtlx_write(minor, (void *)buffer, count, 1);
}
static const struct file_operations rtlx_fops = {
.owner = THIS_MODULE,
.open = file_open,
.release = file_release,
.write = file_write,
.read = file_read,
.poll = file_poll
};
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 rtlx_module_init(void)
{
struct device *dev;
int i, err;
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);
channel_wqs[i].in_open = 0;
dev = device_create(mt_class, NULL, MKDEV(major, i),
"%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(RTLX_TARG_VPE, &notify);
if (cpu_has_vint)
set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
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");