/*
* Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved.
*
* 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/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/cacheflush.h>
#include <asm/atomic.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/rtlx.h>
#define RTLX_MAJOR 64
#define RTLX_TARG_VPE 1
struct rtlx_info *rtlx;
static int major;
static char module_name[] = "rtlx";
static inline int spacefree(int read, int write, int size);
static struct chan_waitqueues {
wait_queue_head_t rt_queue;
wait_queue_head_t lx_queue;
} channel_wqs[RTLX_CHANNELS];
static struct irqaction irq;
static int irq_num;
extern void *vpe_get_shared(int index);
static void rtlx_dispatch(struct pt_regs *regs)
{
do_IRQ(MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ, regs);
}
irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
irqreturn_t r = IRQ_HANDLED;
int i;
for (i = 0; i < RTLX_CHANNELS; i++) {
struct rtlx_channel *chan = &rtlx->channel[i];
if (chan->lx_read != chan->lx_write)
wake_up_interruptible(&channel_wqs[i].lx_queue);
}
return r;
}
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)
{
int i;
if (rtlxi->id != RTLX_ID) {
printk(KERN_WARNING "no valid RTLX id at 0x%p\n", rtlxi);
return (-ENOEXEC);
}
/* 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);
}
/* set up for interrupt handling */
memset(&irq, 0, sizeof(struct irqaction));
if (cpu_has_vint) {
set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
}
irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ;
irq.handler = rtlx_interrupt;
irq.flags = SA_INTERRUPT;
irq.name = "RTLX";
irq.dev_id = rtlx;
setup_irq(irq_num, &irq);
rtlx = rtlxi;
return (0);
}
/* only allow one open process at a time to open each channel */
static int rtlx_open(struct inode *inode, struct file *filp)
{
int minor, ret;
struct rtlx_channel *chan;
/* assume only 1 device at the mo. */
minor = MINOR(inode->i_rdev);
if (rtlx == NULL) {
struct rtlx_info **p;
if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
printk(" vpe_get_shared is NULL. Has an SP program been loaded?\n");
return (-EFAULT);
}
if (*p == NULL) {
printk(" vpe_shared %p %p\n", p, *p);
return (-EFAULT);
}
if ((ret = rtlx_init(*p)) < 0)
return (ret);
}
chan = &rtlx->channel[minor];
/* already open? */
if (chan->lx_state == RTLX_STATE_OPENED)
return (-EBUSY);
chan->lx_state = RTLX_STATE_OPENED;
return (0);
}
static int rtlx_release(struct inode *inode, struct file *filp)
{
int minor;
minor = MINOR(inode->i_rdev);
rtlx->channel[minor].lx_state = RTLX_STATE_UNUSED;
return (0);
}
static unsigned int rtlx_poll(struct file *file, poll_table * wait)
{
int minor;
unsigned int mask = 0;
struct rtlx_channel *chan;
minor = MINOR(file->f_dentry->d_inode->i_rdev);
chan = &rtlx->channel[minor];
poll_wait(file, &channel_wqs[minor].rt_queue, wait);
poll_wait(file, &channel_wqs[minor].lx_queue, wait);
/* data available to read? */
if (chan->lx_read != chan->lx_write)
mask |= POLLIN | POLLRDNORM;
/* space to write */
if (spacefree(chan->rt_read, chan->rt_write, chan->buffer_size))
mask |= POLLOUT | POLLWRNORM;
return (mask);
}
static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count,
loff_t * ppos)
{
size_t fl = 0L;
int minor;
struct rtlx_channel *lx;
DECLARE_WAITQUEUE(wait, current);
minor = MINOR(file->f_dentry->d_inode->i_rdev);
lx = &rtlx->channel[minor];
/* data available? */
if (lx->lx_write == lx->lx_read) {
if (file->f_flags & O_NONBLOCK)
return (0); // -EAGAIN makes cat whinge
/* go to sleep */
add_wait_queue(&channel_wqs[minor].lx_queue, &wait);
set_current_state(TASK_INTERRUPTIBLE);
while (lx->lx_write == lx->lx_read)
schedule();
set_current_state(TASK_RUNNING);
remove_wait_queue(&channel_wqs[minor].lx_queue, &wait);
/* back running */
}
/* 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_user (buffer, &lx->lx_buffer[lx->lx_read], fl);
/* and if there is anything left at the beginning of the buffer */
if ( count - fl )
copy_to_user (buffer + fl, lx->lx_buffer, count - fl);
/* update the index */
lx->lx_read += count;
lx->lx_read %= lx->buffer_size;
return (count);
}
static inline int 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;
}
static ssize_t rtlx_write(struct file *file, const char __user * buffer,
size_t count, loff_t * ppos)
{
int minor;
struct rtlx_channel *rt;
size_t fl;
DECLARE_WAITQUEUE(wait, current);
minor = MINOR(file->f_dentry->d_inode->i_rdev);
rt = &rtlx->channel[minor];
/* any space left... */
if (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) {
if (file->f_flags & O_NONBLOCK)
return (-EAGAIN);
add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
set_current_state(TASK_INTERRUPTIBLE);
while (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size))
schedule();
set_current_state(TASK_RUNNING);
remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
}
/* total number of bytes to copy */
count = min( count, (size_t)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_user(&rt->rt_buffer[rt->rt_write], buffer, fl);
/* if there's any left copy to the beginning of the buffer */
if( count - fl )
copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
rt->rt_write += count;
rt->rt_write %= rt->buffer_size;
return(count);
}
static struct file_operations rtlx_fops = {
.owner = THIS_MODULE,
.open = rtlx_open,
.release = rtlx_release,
.write = rtlx_write,
.read = rtlx_read,
.poll = rtlx_poll
};
static int rtlx_module_init(void)
{
if ((major = register_chrdev(RTLX_MAJOR, module_name, &rtlx_fops)) < 0) {
printk("rtlx_module_init: unable to register device\n");
return (-EBUSY);
}
if (major == 0)
major = RTLX_MAJOR;
return (0);
}
static void rtlx_module_exit(void)
{
unregister_chrdev(major, module_name);
}
module_init(rtlx_module_init);
module_exit(rtlx_module_exit);
MODULE_DESCRIPTION("MIPS RTLX");
MODULE_AUTHOR("Elizabeth Clarke, MIPS Technologies, Inc");
MODULE_LICENSE("GPL");
