powerpc/eeh: I/O chip EEH state retrieval

The patch adds I/O chip backend to retrieve the state for the
indicated PE. While the PE state is temperarily unavailable,
the upper layer (powernv platform) should return default delay
(1 second).
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/eeh-ioda.c

@@ -116,10 +116,107 @@ static int ioda_eeh_set_option(struct eeh_pe *pe, int option)
 	return ret;
 }
 
+/**
+ * ioda_eeh_get_state - Retrieve the state of PE
+ * @pe: EEH PE
+ *
+ * The PE's state should be retrieved from the PEEV, PEST
+ * IODA tables. Since the OPAL has exported the function
+ * to do it, it'd better to use that.
+ */
+static int ioda_eeh_get_state(struct eeh_pe *pe)
+{
+	s64 ret = 0;
+	u8 fstate;
+	u16 pcierr;
+	u32 pe_no;
+	int result;
+	struct pci_controller *hose = pe->phb;
+	struct pnv_phb *phb = hose->private_data;
+
+	/*
+	 * Sanity check on PE address. The PHB PE address should
+	 * be zero.
+	 */
+	if (pe->addr < 0 || pe->addr >= phb->ioda.total_pe) {
+		pr_err("%s: PE address %x out of range [0, %x] "
+		       "on PHB#%x\n",
+		       __func__, pe->addr, phb->ioda.total_pe,
+		       hose->global_number);
+		return EEH_STATE_NOT_SUPPORT;
+	}
+
+	/* Retrieve PE status through OPAL */
+	pe_no = pe->addr;
+	ret = opal_pci_eeh_freeze_status(phb->opal_id, pe_no,
+			&fstate, &pcierr, NULL);
+	if (ret) {
+		pr_err("%s: Failed to get EEH status on "
+		       "PHB#%x-PE#%x\n, err=%lld\n",
+		       __func__, hose->global_number, pe_no, ret);
+		return EEH_STATE_NOT_SUPPORT;
+	}
+
+	/* Check PHB status */
+	if (pe->type & EEH_PE_PHB) {
+		result = 0;
+		result &= ~EEH_STATE_RESET_ACTIVE;
+
+		if (pcierr != OPAL_EEH_PHB_ERROR) {
+			result |= EEH_STATE_MMIO_ACTIVE;
+			result |= EEH_STATE_DMA_ACTIVE;
+			result |= EEH_STATE_MMIO_ENABLED;
+			result |= EEH_STATE_DMA_ENABLED;
+		}
+
+		return result;
+	}
+
+	/* Parse result out */
+	result = 0;
+	switch (fstate) {
+	case OPAL_EEH_STOPPED_NOT_FROZEN:
+		result &= ~EEH_STATE_RESET_ACTIVE;
+		result |= EEH_STATE_MMIO_ACTIVE;
+		result |= EEH_STATE_DMA_ACTIVE;
+		result |= EEH_STATE_MMIO_ENABLED;
+		result |= EEH_STATE_DMA_ENABLED;
+		break;
+	case OPAL_EEH_STOPPED_MMIO_FREEZE:
+		result &= ~EEH_STATE_RESET_ACTIVE;
+		result |= EEH_STATE_DMA_ACTIVE;
+		result |= EEH_STATE_DMA_ENABLED;
+		break;
+	case OPAL_EEH_STOPPED_DMA_FREEZE:
+		result &= ~EEH_STATE_RESET_ACTIVE;
+		result |= EEH_STATE_MMIO_ACTIVE;
+		result |= EEH_STATE_MMIO_ENABLED;
+		break;
+	case OPAL_EEH_STOPPED_MMIO_DMA_FREEZE:
+		result &= ~EEH_STATE_RESET_ACTIVE;
+		break;
+	case OPAL_EEH_STOPPED_RESET:
+		result |= EEH_STATE_RESET_ACTIVE;
+		break;
+	case OPAL_EEH_STOPPED_TEMP_UNAVAIL:
+		result |= EEH_STATE_UNAVAILABLE;
+		break;
+	case OPAL_EEH_STOPPED_PERM_UNAVAIL:
+		result |= EEH_STATE_NOT_SUPPORT;
+		break;
+	default:
+		pr_warning("%s: Unexpected EEH status 0x%x "
+			   "on PHB#%x-PE#%x\n",
+			   __func__, fstate, hose->global_number, pe_no);
+	}
+
+	return result;
+}
+
 struct pnv_eeh_ops ioda_eeh_ops = {
 	.post_init		= ioda_eeh_post_init,
 	.set_option		= ioda_eeh_set_option,
-	.get_state		= NULL,
+	.get_state		= ioda_eeh_get_state,
 	.reset			= NULL,
 	.get_log		= NULL,
 	.configure_bridge	= NULL,