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Turn rtlx upside down.

Browse Source 
o Coding style
 o Race condition on open
 o Switch to dynamic major
 o Header file cleanup
    
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Ralf Baechle 2005-10-31 00:30:39 +00:00
parent 0b154bb7d0
commit afc4841d8a
2 changed files with 105 additions and 120 deletions
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197
arch/mips/kernel/rtlx.c
View File

@ -20,42 +20,42 @@
#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/bitops.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/rtlx.h>
#include <asm/uaccess.h>
#define RTLX_MAJOR 64
#define RTLX_TARG_VPE 1
struct rtlx_info *rtlx;
static struct rtlx_info *rtlx;
static int major;
static char module_name[] = "rtlx";
static inline int spacefree(int read, int write, int size);
static struct irqaction irq;
static int irq_num;
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 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)
@ -63,9 +63,8 @@ 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)
static 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++) {
@ -75,30 +74,7 @@ irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs)
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);
}
return IRQ_HANDLED;
}
/* call when we have the address of the shared structure from the SP side. */
@ -108,7 +84,7 @@ static int rtlx_init(struct rtlx_info *rtlxi)
if (rtlxi->id != RTLX_ID) {
printk(KERN_WARNING "no valid RTLX id at 0x%p\n", rtlxi);
return (-ENOEXEC);
return -ENOEXEC;
}
/* initialise the wait queues */
@ -120,9 +96,8 @@ static int rtlx_init(struct rtlx_info *rtlxi)
/* set up for interrupt handling */
memset(&irq, 0, sizeof(struct irqaction));
if (cpu_has_vint) {
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;
@ -132,7 +107,8 @@ static int rtlx_init(struct rtlx_info *rtlxi)
setup_irq(irq_num, &irq);
rtlx = rtlxi;
return (0);
return 0;
}
/* only allow one open process at a time to open each channel */
@ -147,36 +123,36 @@ static int rtlx_open(struct inode *inode, struct file *filp)
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);
printk(KERN_ERR "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);
printk(KERN_ERR "vpe_shared %p %p\n", p, *p);
return -EFAULT;
}
if ((ret = rtlx_init(*p)) < 0)
return (ret);
return ret;
}
chan = &rtlx->channel[minor];
/* already open? */
if (chan->lx_state == RTLX_STATE_OPENED)
return (-EBUSY);
if (test_and_set_bit(RTLX_STATE_OPENED, &chan->lx_state))
return -EBUSY;
chan->lx_state = RTLX_STATE_OPENED;
return (0);
return 0;
}
static int rtlx_release(struct inode *inode, struct file *filp)
{
int minor;
int minor = MINOR(inode->i_rdev);
minor = MINOR(inode->i_rdev);
rtlx->channel[minor].lx_state = RTLX_STATE_UNUSED;
return (0);
clear_bit(RTLX_STATE_OPENED, &rtlx->channel[minor].lx_state);
smp_mb__after_clear_bit();
return 0;
}
static unsigned int rtlx_poll(struct file *file, poll_table * wait)
@ -199,12 +175,13 @@ static unsigned int rtlx_poll(struct file *file, poll_table * wait)
if (spacefree(chan->rt_read, chan->rt_write, chan->buffer_size))
mask |= POLLOUT | POLLWRNORM;
return (mask);
return mask;
}
static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count,
loff_t * ppos)
{
unsigned long failed;
size_t fl = 0L;
int minor;
struct rtlx_channel *lx;
@ -216,7 +193,7 @@ static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count,
/* data available? */
if (lx->lx_write == lx->lx_read) {
if (file->f_flags & O_NONBLOCK)
return (0); // -EAGAIN makes cat whinge
return 0; /* -EAGAIN makes cat whinge */
/* go to sleep */
add_wait_queue(&channel_wqs[minor].lx_queue, &wait);
@ -232,39 +209,39 @@ static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count,
}
/* find out how much in total */
count = min( count,
(size_t)(lx->lx_write + lx->buffer_size - lx->lx_read) % lx->buffer_size);
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);
fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
copy_to_user (buffer, &lx->lx_buffer[lx->lx_read], fl);
failed = copy_to_user (buffer, &lx->lx_buffer[lx->lx_read], fl);
if (failed) {
count = fl - failed;
goto out;
}
/* 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);
if (count - fl) {
failed = copy_to_user (buffer + fl, lx->lx_buffer, count - fl);
if (failed) {
count -= failed;
goto out;
}
}
out:
/* 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;
return count;
}
static ssize_t rtlx_write(struct file *file, const char __user * buffer,
size_t count, loff_t * ppos)
{
unsigned long failed;
int minor;
struct rtlx_channel *rt;
size_t fl;
@ -277,7 +254,7 @@ static ssize_t rtlx_write(struct file *file, const char __user * buffer,
if (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) {
if (file->f_flags & O_NONBLOCK)
return (-EAGAIN);
return -EAGAIN;
add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
set_current_state(TASK_INTERRUPTIBLE);
@ -290,52 +267,64 @@ static ssize_t rtlx_write(struct file *file, const char __user * buffer,
}
/* total number of bytes to copy */
count = min( count, (size_t)spacefree(rt->rt_read, rt->rt_write, rt->buffer_size) );
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);
failed = copy_from_user(&rt->rt_buffer[rt->rt_write], buffer, fl);
if (failed) {
count = fl - failed;
goto out;
}
/* 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);
if (count - fl) {
failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
if (failed) {
count -= failed;
goto out;
}
}
out:
rt->rt_write += count;
rt->rt_write %= rt->buffer_size;
return(count);
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
.owner = THIS_MODULE,
.open = rtlx_open,
.release = rtlx_release,
.write = rtlx_write,
.read = rtlx_read,
.poll = rtlx_poll
};
static int rtlx_module_init(void)
static char register_chrdev_failed[] __initdata =
KERN_ERR "rtlx_module_init: unable to register device\n";
static int __init 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);
major = register_chrdev(0, module_name, &rtlx_fops);
if (major < 0) {
printk(register_chrdev_failed);
return major;
}
if (major == 0)
major = RTLX_MAJOR;
return (0);
return 0;
}
static void rtlx_module_exit(void)
static void __exit 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_AUTHOR("Elizabeth Clarke, MIPS Technologies, Inc.");
MODULE_LICENSE("GPL");

28
include/asm-mips/rtlx.h
View File

@ -16,21 +16,19 @@
#define RTLX_ID (RTLX_xID | RTLX_VERSION)
#define RTLX_CHANNELS 8
enum rtlx_state {
RTLX_STATE_UNUSED = 0,
RTLX_STATE_INITIALISED,
RTLX_STATE_REMOTE_READY,
RTLX_STATE_OPENED
};
#define RTLX_BUFFER_SIZE 1024
/*
* lx_state bits
*/
#define RTLX_STATE_OPENED 1UL
/* each channel supports read and write.
linux (vpe0) reads lx_buffer and writes rt_buffer
SP (vpe1) reads rt_buffer and writes lx_buffer
*/
typedef struct rtlx_channel {
enum rtlx_state rt_state;
enum rtlx_state lx_state;
struct rtlx_channel {
unsigned long lx_state;
int buffer_size;
@ -43,14 +41,12 @@ typedef struct rtlx_channel {
void *queues;
} rtlx_channel_t;
};
typedef struct rtlx_info {
struct rtlx_info {
unsigned long id;
enum rtlx_state state;
struct rtlx_channel channel[RTLX_CHANNELS];
};
} rtlx_info_t;
#endif
#endif /* _RTLX_H_ */