linux/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/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;
atomic_t 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)
{
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(RTLX_TARG_VPE)) == NULL) {
if (can_sleep) {
__wait_event_interruptible(channel_wqs[index].lx_queue,
(p = vpe_get_shared(RTLX_TARG_VPE)),
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 {
printk(" *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)
{
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);
}
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 lx_write, fl = 0L;
struct rtlx_channel *lx;
if (rtlx == NULL)
return -ENOSYS;
lx = &rtlx->channel[index];
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);
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);
smp_wmb();
lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
smp_wmb();
return count;
}
ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
{
struct rtlx_channel *rt;
size_t rt_read;
size_t fl;
if (rtlx == NULL)
return(-ENOSYS);
rt = &rtlx->channel[index];
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);
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);
smp_wmb();
rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
smp_wmb();
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;
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, (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);
atomic_set(&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");