Do an extra check to see if in-memory tail changed while processing
packets, and if so, going back through the loop again (but only once
per call to ipath_kreceive()). In practice, this seems to be enough
to guarantee that if we crossed the clearing of an interrupt at start of
ipath_intr with a scheduled tail register update, that we'll process the
"extra" packet that lost the interrupt because we cleared it just as it
was about to arrive.
Signed-off-by: Dave Olson <[email protected]>
Signed-off-by: Bryan O'Sullivan <[email protected]>
diff -r 1a4350d895c9 -r 811021b6c112 drivers/infiniband/hw/ipath/ipath_driver.c
--- a/drivers/infiniband/hw/ipath/ipath_driver.c Thu Jun 29 14:33:26 2006 -0700
+++ b/drivers/infiniband/hw/ipath/ipath_driver.c Thu Jun 29 14:33:26 2006 -0700
@@ -870,7 +870,7 @@ void ipath_kreceive(struct ipath_devdata
const u32 maxcnt = dd->ipath_rcvhdrcnt * rsize; /* words */
u32 etail = -1, l, hdrqtail;
struct ips_message_header *hdr;
- u32 eflags, i, etype, tlen, pkttot = 0, updegr=0;
+ u32 eflags, i, etype, tlen, pkttot = 0, updegr=0, reloop=0;
static u64 totcalls; /* stats, may eventually remove */
char emsg[128];
@@ -885,9 +885,11 @@ void ipath_kreceive(struct ipath_devdata
goto bail;
l = dd->ipath_port0head;
- if (l == (u32)le64_to_cpu(*dd->ipath_hdrqtailptr))
+ hdrqtail = (u32) le64_to_cpu(*dd->ipath_hdrqtailptr);
+ if (l == hdrqtail)
goto done;
+reloop:
/* read only once at start for performance */
hdrqtail = (u32)le64_to_cpu(*dd->ipath_hdrqtailptr);
@@ -1011,7 +1013,7 @@ void ipath_kreceive(struct ipath_devdata
*/
if (l == hdrqtail || (i && !(i&0xf))) {
u64 lval;
- if (l == hdrqtail) /* want interrupt only on last */
+ if (l == hdrqtail) /* PE-800 interrupt only on last */
lval = dd->ipath_rhdrhead_intr_off | l;
else
lval = l;
@@ -1021,6 +1023,23 @@ void ipath_kreceive(struct ipath_devdata
etail, 0);
updegr = 0;
}
+ }
+ }
+
+ if (!dd->ipath_rhdrhead_intr_off && !reloop) {
+ /* HT-400 workaround; we can have a race clearing chip
+ * interrupt with another interrupt about to be delivered,
+ * and can clear it before it is delivered on the GPIO
+ * workaround. By doing the extra check here for the
+ * in-memory tail register updating while we were doing
+ * earlier packets, we "almost" guarantee we have covered
+ * that case.
+ */
+ u32 hqtail = (u32)le64_to_cpu(*dd->ipath_hdrqtailptr);
+ if (hqtail != hdrqtail) {
+ hdrqtail = hqtail;
+ reloop = 1; /* loop 1 extra time at most */
+ goto reloop;
}
}
diff -r 1a4350d895c9 -r 811021b6c112 drivers/infiniband/hw/ipath/ipath_intr.c
--- a/drivers/infiniband/hw/ipath/ipath_intr.c Thu Jun 29 14:33:26 2006 -0700
+++ b/drivers/infiniband/hw/ipath/ipath_intr.c Thu Jun 29 14:33:26 2006 -0700
@@ -766,7 +766,7 @@ irqreturn_t ipath_intr(int irq, void *da
u32 istat, chk0rcv = 0;
ipath_err_t estat = 0;
irqreturn_t ret;
- u32 p0bits, oldhead;
+ u32 oldhead, curtail;
static unsigned unexpected = 0;
static const u32 port0rbits = (1U<<INFINIPATH_I_RCVAVAIL_SHIFT) |
(1U<<INFINIPATH_I_RCVURG_SHIFT);
@@ -809,15 +809,16 @@ irqreturn_t ipath_intr(int irq, void *da
* lose intr for later packets that arrive while we are processing.
*/
oldhead = dd->ipath_port0head;
- if (oldhead != (u32) le64_to_cpu(*dd->ipath_hdrqtailptr)) {
+ curtail = (u32)le64_to_cpu(*dd->ipath_hdrqtailptr);
+ if (oldhead != curtail) {
if (dd->ipath_flags & IPATH_GPIO_INTR) {
ipath_write_kreg(dd, dd->ipath_kregs->kr_gpio_clear,
(u64) (1 << 2));
- p0bits = port0rbits | INFINIPATH_I_GPIO;
+ istat = port0rbits | INFINIPATH_I_GPIO;
}
else
- p0bits = port0rbits;
- ipath_write_kreg(dd, dd->ipath_kregs->kr_intclear, p0bits);
+ istat = port0rbits;
+ ipath_write_kreg(dd, dd->ipath_kregs->kr_intclear, istat);
ipath_kreceive(dd);
if (oldhead != dd->ipath_port0head) {
ipath_stats.sps_fastrcvint++;
@@ -827,7 +828,6 @@ irqreturn_t ipath_intr(int irq, void *da
}
istat = ipath_read_kreg32(dd, dd->ipath_kregs->kr_intstatus);
- p0bits = port0rbits;
if (unlikely(!istat)) {
ipath_stats.sps_nullintr++;
@@ -890,19 +890,19 @@ irqreturn_t ipath_intr(int irq, void *da
else {
/* Clear GPIO status bit 2 */
ipath_write_kreg(dd, dd->ipath_kregs->kr_gpio_clear,
- (u64) (1 << 2));
- p0bits |= INFINIPATH_I_GPIO;
+ (u64) (1 << 2));
chk0rcv = 1;
}
}
- chk0rcv |= istat & p0bits;
-
- /*
- * clear the ones we will deal with on this round
- * We clear it early, mostly for receive interrupts, so we
- * know the chip will have seen this by the time we process
- * the queue, and will re-interrupt if necessary. The processor
- * itself won't take the interrupt again until we return.
+ chk0rcv |= istat & port0rbits;
+
+ /*
+ * Clear the interrupt bits we found set, unless they are receive
+ * related, in which case we already cleared them above, and don't
+ * want to clear them again, because we might lose an interrupt.
+ * Clear it early, so we "know" know the chip will have seen this by
+ * the time we process the queue, and will re-interrupt if necessary.
+ * The processor itself won't take the interrupt again until we return.
*/
ipath_write_kreg(dd, dd->ipath_kregs->kr_intclear, istat);
-
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