Author: cem
Date: Tue Oct 13 17:20:47 2015
New Revision: 289232
URL: https://svnweb.freebsd.org/changeset/base/289232
Log:
NTB: MFV 113bf1c9: BWD Link Recovery
The BWD NTB device will drop the link if an error is encountered on the
point-to-point PCI bridge. The link will stay down until all errors are
cleared and the link is re-established. On link down, check to see if
the error is detected, if so do the necessary housekeeping to try and
recover from the error and reestablish the link.
There is a potential race between the 2 NTB devices recovering at the
same time. If the times are synchronized, the link will not recover and
the driver will be stuck in this loop forever. Add a random interval to
the recovery time to prevent this race.
Authored by: Jon Mason
Obtained from: Linux
Sponsored by: EMC / Isilon Storage Division
Modified:
head/sys/dev/ntb/ntb_hw/ntb_hw.c
Modified: head/sys/dev/ntb/ntb_hw/ntb_hw.c
==============================================================================
--- head/sys/dev/ntb/ntb_hw/ntb_hw.c Tue Oct 13 17:20:05 2015
(r289231)
+++ head/sys/dev/ntb/ntb_hw/ntb_hw.c Tue Oct 13 17:20:47 2015
(r289232)
@@ -896,6 +896,7 @@ ntb_handle_heartbeat(void *arg)
if (rc != 0)
device_printf(ntb->device,
"Error determining link status\n");
+
/* Check to see if a link error is the cause of the link down */
if (ntb->link_status == NTB_LINK_DOWN) {
status32 = ntb_reg_read(4, SOC_LTSSMSTATEJMP_OFFSET);
@@ -995,7 +996,15 @@ recover_soc_link(void *arg)
uint16_t status16;
soc_perform_link_restart(ntb);
- pause("Link", SOC_LINK_RECOVERY_TIME * hz / 1000);
+
+ /*
+ * There is a potential race between the 2 NTB devices recovering at
+ * the same time. If the times are the same, the link will not recover
+ * and the driver will be stuck in this loop forever. Add a random
+ * interval to the recovery time to prevent this race.
+ */
+ status32 = arc4random() % SOC_LINK_RECOVERY_TIME;
+ pause("Link", (SOC_LINK_RECOVERY_TIME + status32) * hz / 1000);
status32 = ntb_reg_read(4, SOC_LTSSMSTATEJMP_OFFSET);
if ((status32 & SOC_LTSSMSTATEJMP_FORCEDETECT) != 0)
@@ -1005,12 +1014,17 @@ recover_soc_link(void *arg)
if ((status32 & SOC_IBIST_ERR_OFLOW) != 0)
goto retry;
+ status32 = ntb_reg_read(4, ntb->reg_ofs.lnk_cntl);
+ if ((status32 & SOC_CNTL_LINK_DOWN) != 0)
+ goto out;
+
status16 = ntb_reg_read(2, ntb->reg_ofs.lnk_stat);
width = (status16 & NTB_LINK_WIDTH_MASK) >> 4;
speed = (status16 & NTB_LINK_SPEED_MASK);
if (ntb->link_width != width || ntb->link_speed != speed)
goto retry;
+out:
callout_reset(&ntb->heartbeat_timer, NTB_HB_TIMEOUT * hz,
ntb_handle_heartbeat, ntb);
return;
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
