IB/hfi1: Fix serdes loopback set-up

Change serdes mode setting to use MISC_CONFIG_BITS in
VERIFY_CAP_LOCAL_LINK_WIDTH register. This method of
setting up serdes loopback is universally compatible
across all firmware versions.
Reviewed-by: Jakub Byczkowski <jakub.byczkowski@intel.com>
Signed-off-by: Jan Sokolowski <jan.sokolowski@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/hfi1/chip.c

@@ -9156,25 +9156,6 @@ static int do_quick_linkup(struct hfi1_devdata *dd)
 	return 0; /* success */
 }
 
-/*
- * Set the SerDes to internal loopback mode.
- * Returns 0 on success, -errno on error.
- */
-static int set_serdes_loopback_mode(struct hfi1_devdata *dd)
-{
-	int ret;
-
-	ret = set_physical_link_state(dd, PLS_INTERNAL_SERDES_LOOPBACK);
-	if (ret == HCMD_SUCCESS)
-		return 0;
-	dd_dev_err(dd,
-		   "Set physical link state to SerDes Loopback failed with return %d\n",
-		   ret);
-	if (ret >= 0)
-		ret = -EINVAL;
-	return ret;
-}
-
 /*
  * Do all special steps to set up loopback.
  */
@@ -9200,13 +9181,11 @@ static int init_loopback(struct hfi1_devdata *dd)
 		return 0;
 	}
 
-	/* handle serdes loopback */
-	if (loopback == LOOPBACK_SERDES) {
-		/* internal serdes loopack needs quick linkup on RTL */
-		if (dd->icode == ICODE_RTL_SILICON)
-			quick_linkup = 1;
-		return set_serdes_loopback_mode(dd);
-	}
+	/*
+	 * SerDes loopback init sequence is handled in set_local_link_attributes
+	 */
+	if (loopback == LOOPBACK_SERDES)
+		return 0;
 
 	/* LCB loopback - handled at poll time */
 	if (loopback == LOOPBACK_LCB) {
@@ -9265,7 +9244,7 @@ static int set_local_link_attributes(struct hfi1_pportdata *ppd)
 	u8 tx_polarity_inversion;
 	u8 rx_polarity_inversion;
 	int ret;
-
+	u32 misc_bits = 0;
 	/* reset our fabric serdes to clear any lingering problems */
 	fabric_serdes_reset(dd);
 
@@ -9311,7 +9290,14 @@ static int set_local_link_attributes(struct hfi1_pportdata *ppd)
 	if (ret != HCMD_SUCCESS)
 		goto set_local_link_attributes_fail;
 
-	ret = write_vc_local_link_width(dd, 0, 0,
+	/*
+	 * SerDes loopback init sequence requires
+	 * setting bit 0 of MISC_CONFIG_BITS
+	 */
+	if (loopback == LOOPBACK_SERDES)
+		misc_bits |= 1 << LOOPBACK_SERDES_CONFIG_BIT_MASK_SHIFT;
+
+	ret = write_vc_local_link_width(dd, misc_bits, 0,
 					opa_to_vc_link_widths(
 						ppd->link_width_enabled));
 	if (ret != HCMD_SUCCESS)

drivers/infiniband/hw/hfi1/chip.h

@@ -582,6 +582,9 @@ enum {
 #define LOOPBACK_LCB	2
 #define LOOPBACK_CABLE	3	/* external cable */
 
+/* set up serdes bit in MISC_CONFIG_BITS */
+#define LOOPBACK_SERDES_CONFIG_BIT_MASK_SHIFT 0
+
 /* read and write hardware registers */
 u64 read_csr(const struct hfi1_devdata *dd, u32 offset);
 void write_csr(const struct hfi1_devdata *dd, u32 offset, u64 value);