ChangeSet 1.1358.10.3, 2003/07/10 13:26:49-07:00, benh at kernel.crashing.org
[PATCH] I2C: timer clean up for i2c-keywest.c
On Tue, 2003-07-08 at 12:26, Benjamin Herrenschmidt wrote:
> On Mon, 2003-07-07 at 09:03, Paul Mackerras wrote:
> > This patch changes i2c-keywest.c to use mod_timer instead of a
> > two-line sequence to compute .expires and call add_timer in 3 places.
> > Without this patch I get a BUG from time to time in add_timer.
>
> Ok, here it is. It also remove the never used "polled" mode. The
> driver is now in sync with the more up-to-date 2.4 version ;)
>
> Sorry for not sending that earlier, I forgot about it and didn't
> notice it was out of sync.
And just in case you didn't merge it yet... Here's a version changing
the timer->expire ; add_timer() pairs into calls to mod_timer, makes
the code slighly cleaner.
drivers/i2c/i2c-keywest.c | 90 ++++++++--------------------------------------
1 files changed, 16 insertions(+), 74 deletions(-)
diff -Nru a/drivers/i2c/i2c-keywest.c b/drivers/i2c/i2c-keywest.c
--- a/drivers/i2c/i2c-keywest.c Sat Jul 19 08:48:26 2003
+++ b/drivers/i2c/i2c-keywest.c Sat Jul 19 08:48:26 2003
@@ -66,8 +66,6 @@
#include "i2c-keywest.h"
-#undef POLLED_MODE
-
#define DBG(x...) do {\
if (debug > 0) \
printk(KERN_DEBUG "KW:" x); \
@@ -85,27 +83,6 @@
static struct keywest_iface *ifaces = NULL;
-#ifdef POLLED_MODE
-/* This isn't fast, but will go once I implement interrupt with
- * proper timeout
- */
-static u8
-wait_interrupt(struct keywest_iface* iface)
-{
- int i;
- u8 isr;
-
- for (i = 0; i < POLL_TIMEOUT; i++) {
- isr = read_reg(reg_isr) & KW_I2C_IRQ_MASK;
- if (isr != 0)
- return isr;
- current->state = TASK_UNINTERRUPTIBLE;
- schedule_timeout(1);
- }
- return isr;
-}
-#endif /* POLLED_MODE */
-
static void
do_stop(struct keywest_iface* iface, int result)
@@ -116,16 +93,17 @@
}
/* Main state machine for standard & standard sub mode */
-static void
+static int
handle_interrupt(struct keywest_iface *iface, u8 isr)
{
int ack;
+ int rearm_timer = 1;
DBG("handle_interrupt(), got: %x, status: %x, state: %d\n",
isr, read_reg(reg_status), iface->state);
if (isr == 0 && iface->state != state_stop) {
do_stop(iface, -1);
- return;
+ return rearm_timer;
}
if (isr & KW_I2C_IRQ_STOP && iface->state != state_stop) {
iface->result = -1;
@@ -196,20 +174,19 @@
if (!(isr & KW_I2C_IRQ_STOP) && (++iface->stopretry) < 10)
do_stop(iface, -1);
else {
+ rearm_timer = 0;
iface->state = state_idle;
write_reg(reg_control, 0x00);
write_reg(reg_ier, 0x00);
-#ifndef POLLED_MODE
complete(&iface->complete);
-#endif /* POLLED_MODE */
}
break;
}
write_reg(reg_isr, isr);
-}
-#ifndef POLLED_MODE
+ return rearm_timer;
+}
/* Interrupt handler */
static irqreturn_t
@@ -219,11 +196,8 @@
spin_lock(&iface->lock);
del_timer(&iface->timeout_timer);
- handle_interrupt(iface, read_reg(reg_isr));
- if (iface->state != state_idle) {
- iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
- add_timer(&iface->timeout_timer);
- }
+ if (handle_interrupt(iface, read_reg(reg_isr)))
+ mod_timer(&iface->timeout_timer, jiffies + POLL_TIMEOUT);
spin_unlock(&iface->lock);
return IRQ_HANDLED;
}
@@ -235,16 +209,11 @@
DBG("timeout !\n");
spin_lock_irq(&iface->lock);
- handle_interrupt(iface, read_reg(reg_isr));
- if (iface->state != state_idle) {
- iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
- add_timer(&iface->timeout_timer);
- }
+ if (handle_interrupt(iface, read_reg(reg_isr)))
+ mod_timer(&iface->timeout_timer, jiffies + POLL_TIMEOUT);
spin_unlock(&iface->lock);
}
-#endif /* POLLED_MODE */
-
/*
* SMBUS-type transfer entrypoint
*/
@@ -331,24 +300,13 @@
write_reg(reg_subaddr, command);
/* Arm timeout */
- iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
- add_timer(&iface->timeout_timer);
+ mod_timer(&iface->timeout_timer, jiffies + POLL_TIMEOUT);
/* Start sending address & enable interrupt*/
write_reg(reg_control, read_reg(reg_control) | KW_I2C_CTL_XADDR);
write_reg(reg_ier, KW_I2C_IRQ_MASK);
-#ifdef POLLED_MODE
- DBG("using polled mode...\n");
- /* State machine, to turn into an interrupt handler */
- while(iface->state != state_idle) {
- u8 isr = wait_interrupt(iface);
- handle_interrupt(iface, isr);
- }
-#else /* POLLED_MODE */
- DBG("using interrupt mode...\n");
wait_for_completion(&iface->complete);
-#endif /* POLLED_MODE */
rc = iface->result;
DBG("transfer done, result: %d\n", rc);
@@ -421,24 +379,13 @@
((iface->read_write == I2C_SMBUS_READ) ? 0x01 : 0x00));
/* Arm timeout */
- iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
- add_timer(&iface->timeout_timer);
+ mod_timer(&iface->timeout_timer, jiffies + POLL_TIMEOUT);
/* Start sending address & enable interrupt*/
write_reg(reg_control, read_reg(reg_control) | KW_I2C_CTL_XADDR);
write_reg(reg_ier, KW_I2C_IRQ_MASK);
-#ifdef POLLED_MODE
- DBG("using polled mode...\n");
- /* State machine, to turn into an interrupt handler */
- while(iface->state != state_idle) {
- u8 isr = wait_interrupt(iface);
- handle_interrupt(iface, isr);
- }
-#else /* POLLED_MODE */
- DBG("using interrupt mode...\n");
wait_for_completion(&iface->complete);
-#endif /* POLLED_MODE */
rc = iface->result;
if (rc == 0)
@@ -540,8 +487,8 @@
*prate);
}
- /* Select standard sub mode */
- iface->cur_mode |= KW_I2C_MODE_STANDARDSUB;
+ /* Select standard mode by default */
+ iface->cur_mode |= KW_I2C_MODE_STANDARD;
/* Write mode */
write_reg(reg_mode, iface->cur_mode);
@@ -550,7 +497,6 @@
write_reg(reg_ier, 0x00);
write_reg(reg_isr, KW_I2C_IRQ_MASK);
-#ifndef POLLED_MODE
/* Request chip interrupt */
rc = request_irq(iface->irq, keywest_irq, 0, "keywest i2c", iface);
if (rc) {
@@ -559,7 +505,6 @@
kfree(iface);
return -ENODEV;
}
-#endif /* POLLED_MODE */
for (i=0; i<nchan; i++) {
struct keywest_chan* chan = &iface->channels[i];
@@ -609,19 +554,16 @@
/* Make sure we stop all activity */
down(&iface->sem);
-#ifndef POLLED_MODE
spin_lock_irq(&iface->lock);
while (iface->state != state_idle) {
spin_unlock_irq(&iface->lock);
- schedule();
+ set_task_state(current,TASK_UNINTERRUPTIBLE);
+ schedule_timeout(HZ/10);
spin_lock_irq(&iface->lock);
}
-#endif /* POLLED_MODE */
iface->state = state_dead;
-#ifndef POLLED_MODE
spin_unlock_irq(&iface->lock);
free_irq(iface->irq, iface);
-#endif /* POLLED_MODE */
up(&iface->sem);
/* Release all channels */
