ioat: switch watchdog and reset handler from workqueue to timer
In order to support dynamic resizing of the descriptor ring or polling
for a descriptor in the presence of a hung channel the reset handler
needs to make progress while in a non-preemptible context. The current
workqueue implementation precludes polling channel reset completion
under spin_lock().
This conversion also allows us to return to opportunistic cleanup in the
ioat2 case as the timer implementation guarantees at least one cleanup
after every descriptor is submitted. This means the worst case
completion latency becomes the timer frequency (for exceptional
circumstances), but with the benefit of avoiding busy waiting when the
lock is contended.
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/idle/i7300_idle.c b/drivers/idle/i7300_idle.c
index f2ec724..1f20a04 100644
--- a/drivers/idle/i7300_idle.c
+++ b/drivers/idle/i7300_idle.c
@@ -126,9 +126,9 @@
udelay(10);
sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
- IOAT_CHANSTS_DMA_TRANSFER_STATUS;
+ IOAT_CHANSTS_STATUS;
- if (sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE)
+ if (sts != IOAT_CHANSTS_ACTIVE)
break;
}
@@ -160,9 +160,9 @@
udelay(1000);
chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
- IOAT_CHANSTS_DMA_TRANSFER_STATUS;
+ IOAT_CHANSTS_STATUS;
- if (chan_sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_DONE) {
+ if (chan_sts != IOAT_CHANSTS_DONE) {
/* Not complete, reset the channel */
writeb(IOAT_CHANCMD_RESET,
ioat_chanbase + IOAT1_CHANCMD_OFFSET);
@@ -288,9 +288,9 @@
ioat_chanbase + IOAT1_CHANCMD_OFFSET);
chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
- IOAT_CHANSTS_DMA_TRANSFER_STATUS;
+ IOAT_CHANSTS_STATUS;
- if (chan_sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) {
+ if (chan_sts != IOAT_CHANSTS_ACTIVE) {
writew(0, ioat_chanbase + IOAT_CHANCTRL_OFFSET);
break;
}
@@ -298,14 +298,14 @@
}
chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
- IOAT_CHANSTS_DMA_TRANSFER_STATUS;
+ IOAT_CHANSTS_STATUS;
/*
* We tried to reset multiple times. If IO A/T channel is still active
* flag an error and return without cleanup. Memory leak is better
* than random corruption in that extreme error situation.
*/
- if (chan_sts == IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) {
+ if (chan_sts == IOAT_CHANSTS_ACTIVE) {
printk(KERN_ERR I7300_PRINT "Unable to stop IO A/T channels."
" Not freeing resources\n");
return;