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authorDan Williams <dan.j.williams@intel.com>2009-09-08 15:01:49 -0400
committerDan Williams <dan.j.williams@intel.com>2009-09-08 20:30:24 -0400
commit09c8a5b85e5f1e74a19bdd7c85547429d51df1cd (patch)
tree9bb255d9f596ab062996de49032875e8b9253971 /drivers/idle/i7300_idle.c
parentad643f54c8514998333bc6c7b201fda2267496be (diff)
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>
Diffstat (limited to 'drivers/idle/i7300_idle.c')
-rw-r--r--drivers/idle/i7300_idle.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/drivers/idle/i7300_idle.c b/drivers/idle/i7300_idle.c
index f2ec7243549..1f20a042a4f 100644
--- a/drivers/idle/i7300_idle.c
+++ b/drivers/idle/i7300_idle.c
@@ -126,9 +126,9 @@ static void i7300_idle_ioat_stop(void)
126 udelay(10); 126 udelay(10);
127 127
128 sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) & 128 sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
129 IOAT_CHANSTS_DMA_TRANSFER_STATUS; 129 IOAT_CHANSTS_STATUS;
130 130
131 if (sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) 131 if (sts != IOAT_CHANSTS_ACTIVE)
132 break; 132 break;
133 133
134 } 134 }
@@ -160,9 +160,9 @@ static int __init i7300_idle_ioat_selftest(u8 *ctl,
160 udelay(1000); 160 udelay(1000);
161 161
162 chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) & 162 chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
163 IOAT_CHANSTS_DMA_TRANSFER_STATUS; 163 IOAT_CHANSTS_STATUS;
164 164
165 if (chan_sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_DONE) { 165 if (chan_sts != IOAT_CHANSTS_DONE) {
166 /* Not complete, reset the channel */ 166 /* Not complete, reset the channel */
167 writeb(IOAT_CHANCMD_RESET, 167 writeb(IOAT_CHANCMD_RESET,
168 ioat_chanbase + IOAT1_CHANCMD_OFFSET); 168 ioat_chanbase + IOAT1_CHANCMD_OFFSET);
@@ -288,9 +288,9 @@ static void __exit i7300_idle_ioat_exit(void)
288 ioat_chanbase + IOAT1_CHANCMD_OFFSET); 288 ioat_chanbase + IOAT1_CHANCMD_OFFSET);
289 289
290 chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) & 290 chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
291 IOAT_CHANSTS_DMA_TRANSFER_STATUS; 291 IOAT_CHANSTS_STATUS;
292 292
293 if (chan_sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) { 293 if (chan_sts != IOAT_CHANSTS_ACTIVE) {
294 writew(0, ioat_chanbase + IOAT_CHANCTRL_OFFSET); 294 writew(0, ioat_chanbase + IOAT_CHANCTRL_OFFSET);
295 break; 295 break;
296 } 296 }
@@ -298,14 +298,14 @@ static void __exit i7300_idle_ioat_exit(void)
298 } 298 }
299 299
300 chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) & 300 chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
301 IOAT_CHANSTS_DMA_TRANSFER_STATUS; 301 IOAT_CHANSTS_STATUS;
302 302
303 /* 303 /*
304 * We tried to reset multiple times. If IO A/T channel is still active 304 * We tried to reset multiple times. If IO A/T channel is still active
305 * flag an error and return without cleanup. Memory leak is better 305 * flag an error and return without cleanup. Memory leak is better
306 * than random corruption in that extreme error situation. 306 * than random corruption in that extreme error situation.
307 */ 307 */
308 if (chan_sts == IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) { 308 if (chan_sts == IOAT_CHANSTS_ACTIVE) {
309 printk(KERN_ERR I7300_PRINT "Unable to stop IO A/T channels." 309 printk(KERN_ERR I7300_PRINT "Unable to stop IO A/T channels."
310 " Not freeing resources\n"); 310 " Not freeing resources\n");
311 return; 311 return;