powerpc/pci: [PATCH 1/1]: PCIE PHB reset

[wenxiong@linux.vnet.ibm.com]

From: Wen Xiong <wenxiong@linux.vnet.ibm.com>

Several device drivers hit EEH(Extended Error handling) when triggering
kdump on Pseries PowerVM. This patch implemented a reset of the PHBs
in pci general code. PHB reset stop all PCI transactions from previous
kernel. We have tested the patch in several enviroments:
- direct slot adapters
- adapters under the switch
- a VF adapter in PowerVM
- a VF adapter/adapter in KVM guest.

Signed-off-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/pseries/pci.c | 153 +++++++++++++++++++++++++++
 1 file changed, 153 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/pci.c b/arch/powerpc/platforms/pseries/pci.c
index 911534b89c85..aac7f00696d2 100644
--- a/arch/powerpc/platforms/pseries/pci.c
+++ b/arch/powerpc/platforms/pseries/pci.c
@@ -11,6 +11,8 @@
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <linux/string.h>
+#include <linux/crash_dump.h>
+#include <linux/delay.h>
 
 #include <asm/eeh.h>
 #include <asm/pci-bridge.h>
@@ -354,3 +356,154 @@ int pseries_root_bridge_prepare(struct pci_host_bridge *bridge)
 
 	return 0;
 }
+
+/**
+ * pseries_get_pdn_addr - Retrieve PHB address
+ * @pe: EEH PE
+ *
+ * Retrieve the assocated PHB address. Actually, there're 2 RTAS
+ * function calls dedicated for the purpose. We need implement
+ * it through the new function and then the old one. Besides,
+ * you should make sure the config address is figured out from
+ * FDT node before calling the function.
+ *
+ */
+static int pseries_get_pdn_addr(struct pci_controller *phb)
+{
+	int ret = -1;
+	int rets[3];
+	int ibm_get_config_addr_info;
+	int ibm_get_config_addr_info2;
+	int config_addr = 0;
+	struct pci_dn *root_pdn, *pdn;
+
+	ibm_get_config_addr_info2   = rtas_token("ibm,get-config-addr-info2");
+	ibm_get_config_addr_info    = rtas_token("ibm,get-config-addr-info");
+
+	root_pdn = PCI_DN(phb->dn);
+	pdn = list_first_entry(&root_pdn->child_list, struct pci_dn, list);
+	config_addr = (pdn->busno << 16) | (pdn->devfn << 8);
+
+	if (ibm_get_config_addr_info2 != RTAS_UNKNOWN_SERVICE) {
+		/*
+		 * First of all, we need to make sure there has one PE
+		 * associated with the device. Otherwise, PE address is
+		 * meaningless.
+		 */
+		ret = rtas_call(ibm_get_config_addr_info2, 4, 2, rets,
+			config_addr, BUID_HI(pdn->phb->buid),
+			BUID_LO(pdn->phb->buid), 1);
+		if (ret || (rets[0] == 0)) {
+			pr_warn("%s: Failed to get address for PHB#%x-PE# "
+				"option=%d config_addr=%x\n",
+				__func__, pdn->phb->global_number, 1, rets[0]);
+			return -1;
+		}
+
+		/* Retrieve the associated PE config address */
+		ret = rtas_call(ibm_get_config_addr_info2, 4, 2, rets,
+			config_addr, BUID_HI(pdn->phb->buid),
+			BUID_LO(pdn->phb->buid), 0);
+		if (ret) {
+			pr_warn("%s: Failed to get address for PHB#%x-PE# "
+				"option=%d config_addr=%x\n",
+				__func__, pdn->phb->global_number, 0, rets[0]);
+			return -1;
+		}
+		return rets[0];
+	}
+
+	if (ibm_get_config_addr_info != RTAS_UNKNOWN_SERVICE) {
+		ret = rtas_call(ibm_get_config_addr_info, 4, 2, rets,
+			config_addr, BUID_HI(pdn->phb->buid),
+			BUID_LO(pdn->phb->buid), 0);
+		if (ret || rets[0]) {
+			pr_warn("%s: Failed to get address for PHB#%x-PE# "
+				"config_addr=%x\n",
+				__func__, pdn->phb->global_number, rets[0]);
+			return -1;
+		}
+		return rets[0];
+	}
+
+	return ret;
+}
+
+static int __init pseries_phb_reset(void)
+{
+	struct pci_controller *phb;
+	int config_addr;
+	int ibm_set_slot_reset;
+	int ibm_configure_pe;
+	int ret;
+
+	if (is_kdump_kernel() || reset_devices) {
+		pr_info("Issue PHB reset ...\n");
+		ibm_set_slot_reset = rtas_token("ibm,set-slot-reset");
+		ibm_configure_pe = rtas_token("ibm,configure-pe");
+
+		if (ibm_set_slot_reset == RTAS_UNKNOWN_SERVICE ||
+				ibm_configure_pe == RTAS_UNKNOWN_SERVICE) {
+			pr_info("%s: EEH functionality not supported\n",
+				__func__);
+		}
+
+		list_for_each_entry(phb, &hose_list, list_node) {
+			config_addr = pseries_get_pdn_addr(phb);
+			if (config_addr == -1)
+				continue;
+
+			ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
+				config_addr, BUID_HI(phb->buid),
+				BUID_LO(phb->buid), EEH_RESET_FUNDAMENTAL);
+
+			/* If fundamental-reset not supported, try hot-reset */
+			if (ret == -8)
+				ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
+					config_addr, BUID_HI(phb->buid),
+					BUID_LO(phb->buid), EEH_RESET_HOT);
+
+			if (ret) {
+				pr_err("%s: fail with rtas_call fundamental reset=%d\n",
+					__func__, ret);
+				continue;
+			}
+		}
+		msleep(EEH_PE_RST_SETTLE_TIME);
+
+		list_for_each_entry(phb, &hose_list, list_node) {
+			config_addr = pseries_get_pdn_addr(phb);
+			if (config_addr == -1)
+				continue;
+
+			ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
+				config_addr, BUID_HI(phb->buid),
+				BUID_LO(phb->buid), EEH_RESET_DEACTIVATE);
+			if (ret) {
+				pr_err("%s: fail with rtas_call deactive=%d\n",
+					__func__, ret);
+				continue;
+			}
+		}
+		msleep(EEH_PE_RST_SETTLE_TIME);
+
+		list_for_each_entry(phb, &hose_list, list_node) {
+			config_addr = pseries_get_pdn_addr(phb);
+			if (config_addr == -1)
+				continue;
+
+			ret = rtas_call(ibm_configure_pe, 3, 1, NULL,
+				config_addr, BUID_HI(phb->buid),
+				BUID_LO(phb->buid));
+			if (ret) {
+				pr_err("%s: fail with rtas_call configure_pe =%d\n",
+					__func__, ret);
+				continue;
+			}
+		}
+	}
+
+	return 0;
+}
+postcore_initcall(pseries_phb_reset);
+
-- 
2.18.1