[Skiboot] [PATCH v2 5/5] npu2-opencapi: Fix link state to report link down

[Frederic Barrat]

From: Frederic Barrat <fbarrat at linux.vnet.ibm.com>

The PHB callback 'get_link_state' is always reporting the link width,
irrespective of the link status and even when the link is down. It is
causing too much work (and failures) when the PHB is probed during pci
init.
The fix is to look at the link status first and report the link as
down when appropriate.

Signed-off-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>
---
v2:
	no change

hw/npu2-opencapi.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/npu2-opencapi.c b/hw/npu2-opencapi.c
index af6c4871..50ef8766 100644
--- a/hw/npu2-opencapi.c
+++ b/hw/npu2-opencapi.c
@@ -80,6 +80,7 @@
 
 #define OCAPI_LINK_TRAINING_RETRIES	5
 #define OCAPI_LINK_TRAINING_TIMEOUT	3000 /* ms */
+#define OCAPI_LINK_STATE_TRAINED        0x7
 
 enum npu2_link_training_state {
 	NPU2_TRAIN_DEFAULT, /* fully train the link */
@@ -1032,10 +1033,17 @@ static int64_t npu2_opencapi_get_link_state(struct pci_slot *slot, uint8_t *val)
 {
 	struct npu2_dev *dev = phb_to_npu2_dev_ocapi(slot->phb);
 	uint64_t reg;
-	int64_t link_width, rc = OPAL_SUCCESS;
+	int64_t link_width, training_status, rc = OPAL_SUCCESS;
 
 	reg = get_odl_status(dev->npu->chip_id, dev->index);
 	link_width = GETFIELD(OB_ODL_STATUS_TRAINED_MODE, reg);
+	training_status = GETFIELD(OB_ODL_STATUS_TRAINING_STATE_MACHINE, reg);
+
+	if (training_status != OCAPI_LINK_STATE_TRAINED) {
+		*val = OPAL_SHPC_LINK_DOWN;
+		return OPAL_SUCCESS;
+	}
+
 	switch (link_width) {
 	case 0b0001:
 		*val = OPAL_SHPC_LINK_UP_x4;
@@ -1086,7 +1094,8 @@ static int64_t npu2_opencapi_poll_link(struct pci_slot *slot)
 		/* fall-through */
 	case OCAPI_SLOT_LINK_WAIT:
 		reg = get_odl_status(chip_id, dev->index);
-		if (GETFIELD(OB_ODL_STATUS_TRAINING_STATE_MACHINE, reg) == 0x7) {
+		if (GETFIELD(OB_ODL_STATUS_TRAINING_STATE_MACHINE, reg) ==
+			OCAPI_LINK_STATE_TRAINED) {
 			OCAPIINF(dev, "link trained in %lld ms\n",
 				OCAPI_LINK_TRAINING_TIMEOUT - slot->retries);
 			pci_slot_set_state(slot, OCAPI_SLOT_LINK_TRAINED);
-- 
2.14.1