hw/npu2: Report errors to the OS if an OpenCAPI brick is fenced

Now that the NPU may report interrupts due to the link going down
unexpectedly, report those errors to the OS when queried by the
'next_error' PHB callback.

The hardware doesn't support recovery of the link when it goes down
unexpectedly. So we report the PHB as dead, so that the OS can log the
proper message, notify the drivers and take the devices down.

Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

2 files changed, 52 insertions, 4 deletions

diff --git a/hw/npu2-opencapi.c b/hw/npu2-opencapi.c
index 285615a5..9df51b22 100644
--- a/hw/npu2-opencapi.c
+++ b/hw/npu2-opencapi.c
@@ -1434,18 +1434,64 @@ static int64_t npu2_opencapi_ioda_reset(struct phb __unused *phb,
 	return OPAL_SUCCESS;
 }
 
-static int64_t npu2_opencapi_set_pe(struct phb __unused *phb,
-				    uint64_t __unused pe_num,
+static int64_t npu2_opencapi_set_pe(struct phb *phb,
+				    uint64_t pe_num,
 				    uint64_t __unused bdfn,
 				    uint8_t __unused bcompare,
 				    uint8_t __unused dcompare,
 				    uint8_t __unused fcompare,
 				    uint8_t __unused action)
 {
+	struct npu2_dev *dev = phb_to_npu2_dev_ocapi(phb);
 	/*
 	 * Ignored on OpenCAPI - we use fixed PE assignments. May need
 	 * addressing when we support dual-link devices.
+	 *
+	 * We nonetheless store the PE reported by the OS so that we
+	 * can send it back in case of error. If there are several PCI
+	 * functions on the device, the OS can define many PEs, we
+	 * only keep one, the OS will handle it.
 	 */
+	dev->linux_pe = pe_num;
+	return OPAL_SUCCESS;
+}
+
+static int64_t npu2_opencapi_freeze_status(struct phb *phb __unused,
+			   uint64_t pe_number __unused,
+			   uint8_t *freeze_state,
+			   uint16_t *pci_error_type,
+			   uint16_t *severity)
+{
+	*freeze_state = OPAL_EEH_STOPPED_NOT_FROZEN;
+	*pci_error_type = OPAL_EEH_NO_ERROR;
+	if (severity)
+		*severity = OPAL_EEH_SEV_NO_ERROR;
+
+	return OPAL_SUCCESS;
+}
+
+static int64_t npu2_opencapi_eeh_next_error(struct phb *phb,
+				   uint64_t *first_frozen_pe,
+				   uint16_t *pci_error_type,
+				   uint16_t *severity)
+{
+	struct npu2_dev *dev = phb_to_npu2_dev_ocapi(phb);
+	uint64_t reg;
+
+	if (!first_frozen_pe || !pci_error_type || !severity)
+		return OPAL_PARAMETER;
+
+	reg = npu2_read(dev->npu, NPU2_MISC_FENCE_STATE);
+	if (reg & PPC_BIT(dev->brick_index)) {
+		OCAPIERR(dev, "Brick %d fenced!\n", dev->brick_index);
+		*first_frozen_pe = dev->linux_pe;
+		*pci_error_type = OPAL_EEH_PHB_ERROR;
+		*severity = OPAL_EEH_SEV_PHB_DEAD;
+	} else {
+		*first_frozen_pe = -1;
+		*pci_error_type = OPAL_EEH_NO_ERROR;
+		*severity = OPAL_EEH_SEV_NO_ERROR;
+	}
 	return OPAL_SUCCESS;
 }
 
@@ -1646,6 +1692,7 @@ static void setup_device(struct npu2_dev *dev)
 	dev->phb_ocapi.scan_map = 0;
 
 	dev->bdfn = 0;
+	dev->linux_pe = -1;
 	dev->train_need_fence = false;
 	dev->train_fenced = false;
 
@@ -1765,10 +1812,10 @@ static const struct phb_ops npu2_opencapi_ops = {
 	.get_msi_64		= NULL,
 	.set_pe			= npu2_opencapi_set_pe,
 	.set_peltv		= NULL,
-	.eeh_freeze_status	= npu2_freeze_status,  /* TODO */
+	.eeh_freeze_status	= npu2_opencapi_freeze_status,
 	.eeh_freeze_clear	= NULL,
 	.eeh_freeze_set		= NULL,
-	.next_error		= NULL,
+	.next_error		= npu2_opencapi_eeh_next_error,
 	.err_inject		= NULL,
 	.get_diag_data		= NULL,
 	.get_diag_data2		= NULL,
diff --git a/include/npu2.h b/include/npu2.h
index 6c73679f..ef4e7aff 100644
--- a/include/npu2.h
+++ b/include/npu2.h
@@ -157,6 +157,7 @@ struct npu2_dev {
 
 	/* OpenCAPI */
 	struct phb		phb_ocapi;
+	uint64_t		linux_pe;
 	bool			train_need_fence;
 	bool			train_fenced;
 };