IB/hfi1: Add QSFP sanity pre-check
Sometimes a QSFP device does not respond in the expected time
after a power-on. Add a read pre-check/retry when starting
the link on driver load.
Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/hw/hfi1/chip.c b/drivers/infiniband/hw/hfi1/chip.c
index b32638d..ec3635a 100644
--- a/drivers/infiniband/hw/hfi1/chip.c
+++ b/drivers/infiniband/hw/hfi1/chip.c
@@ -9490,6 +9490,78 @@
write_csr(dd, DC_LCB_CFG_TX_FIFOS_RESET, 0x00);
}
+/*
+ * Perform a test read on the QSFP. Return 0 on success, -ERRNO
+ * on error.
+ */
+static int test_qsfp_read(struct hfi1_pportdata *ppd)
+{
+ int ret;
+ u8 status;
+
+ /* report success if not a QSFP */
+ if (ppd->port_type != PORT_TYPE_QSFP)
+ return 0;
+
+ /* read byte 2, the status byte */
+ ret = one_qsfp_read(ppd, ppd->dd->hfi1_id, 2, &status, 1);
+ if (ret < 0)
+ return ret;
+ if (ret != 1)
+ return -EIO;
+
+ return 0; /* success */
+}
+
+/*
+ * Values for QSFP retry.
+ *
+ * Give up after 10s (20 x 500ms). The overall timeout was empirically
+ * arrived at from experience on a large cluster.
+ */
+#define MAX_QSFP_RETRIES 20
+#define QSFP_RETRY_WAIT 500 /* msec */
+
+/*
+ * Try a QSFP read. If it fails, schedule a retry for later.
+ * Called on first link activation after driver load.
+ */
+static void try_start_link(struct hfi1_pportdata *ppd)
+{
+ if (test_qsfp_read(ppd)) {
+ /* read failed */
+ if (ppd->qsfp_retry_count >= MAX_QSFP_RETRIES) {
+ dd_dev_err(ppd->dd, "QSFP not responding, giving up\n");
+ return;
+ }
+ dd_dev_info(ppd->dd,
+ "QSFP not responding, waiting and retrying %d\n",
+ (int)ppd->qsfp_retry_count);
+ ppd->qsfp_retry_count++;
+ queue_delayed_work(ppd->hfi1_wq, &ppd->start_link_work,
+ msecs_to_jiffies(QSFP_RETRY_WAIT));
+ return;
+ }
+ ppd->qsfp_retry_count = 0;
+
+ /*
+ * Tune the SerDes to a ballpark setting for optimal signal and bit
+ * error rate. Needs to be done before starting the link.
+ */
+ tune_serdes(ppd);
+ start_link(ppd);
+}
+
+/*
+ * Workqueue function to start the link after a delay.
+ */
+void handle_start_link(struct work_struct *work)
+{
+ struct hfi1_pportdata *ppd = container_of(work, struct hfi1_pportdata,
+ start_link_work.work);
+ try_start_link(ppd);
+}
+
int bringup_serdes(struct hfi1_pportdata *ppd)
{
struct hfi1_devdata *dd = ppd->dd;
@@ -9525,14 +9597,8 @@
set_qsfp_int_n(ppd, 1);
}
- /*
- * Tune the SerDes to a ballpark setting for
- * optimal signal and bit error rate
- * Needs to be done before starting the link
- */
- tune_serdes(ppd);
-
- return start_link(ppd);
+ try_start_link(ppd);
+ return 0;
}
void hfi1_quiet_serdes(struct hfi1_pportdata *ppd)
@@ -9549,6 +9615,10 @@
ppd->driver_link_ready = 0;
ppd->link_enabled = 0;
+ ppd->qsfp_retry_count = MAX_QSFP_RETRIES; /* prevent more retries */
+ flush_delayed_work(&ppd->start_link_work);
+ cancel_delayed_work_sync(&ppd->start_link_work);
+
ppd->offline_disabled_reason =
HFI1_ODR_MASK(OPA_LINKDOWN_REASON_SMA_DISABLED);
set_link_down_reason(ppd, OPA_LINKDOWN_REASON_SMA_DISABLED, 0,