powerpc/pseries: PCIE PHB reset
authorWen Xiong <wenxiong@linux.vnet.ibm.com>
Mon, 13 Jul 2020 14:39:33 +0000 (09:39 -0500)
committerMichael Ellerman <mpe@ellerman.id.au>
Thu, 23 Jul 2020 07:43:30 +0000 (17:43 +1000)
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 when triggering kdump. PHB reset stop all
PCI transactions from normal 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>
[mpe: Fix broken whitespace, subject & SOB formatting]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1594651173-32166-1-git-send-email-wenxiong@linux.vnet.ibm.com
arch/powerpc/platforms/pseries/eeh_pseries.c

index ace117f..47760fb 100644 (file)
@@ -24,6 +24,7 @@
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/spinlock.h>
+#include <linux/crash_dump.h>
 
 #include <asm/eeh.h>
 #include <asm/eeh_event.h>
@@ -80,6 +81,152 @@ void pseries_pcibios_bus_add_device(struct pci_dev *pdev)
        eeh_probe_device(pdev);
 }
 
+
+/**
+ * pseries_eeh_get_config_addr - Retrieve config address
+ *
+ * Retrieve the assocated config 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.
+ *
+ * It's notable that zero'ed return value means invalid PE config
+ * address.
+ */
+static int pseries_eeh_get_config_addr(struct pci_controller *phb, int config_addr)
+{
+       int ret = 0;
+       int rets[3];
+
+       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(phb->buid),
+                               BUID_LO(phb->buid), 1);
+               if (ret || (rets[0] == 0))
+                       return 0;
+
+               /* Retrieve the associated PE config address */
+               ret = rtas_call(ibm_get_config_addr_info2, 4, 2, rets,
+                               config_addr, BUID_HI(phb->buid),
+                               BUID_LO(phb->buid), 0);
+               if (ret) {
+                       pr_warn("%s: Failed to get address for PHB#%x-PE#%x\n",
+                               __func__, phb->global_number, config_addr);
+                       return 0;
+               }
+
+               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(phb->buid),
+                               BUID_LO(phb->buid), 0);
+               if (ret) {
+                       pr_warn("%s: Failed to get address for PHB#%x-PE#%x\n",
+                               __func__, phb->global_number, config_addr);
+                       return 0;
+               }
+
+               return rets[0];
+       }
+
+       return ret;
+}
+
+/**
+ * pseries_eeh_phb_reset - Reset the specified PHB
+ * @phb: PCI controller
+ * @config_adddr: the associated config address
+ * @option: reset option
+ *
+ * Reset the specified PHB/PE
+ */
+static int pseries_eeh_phb_reset(struct pci_controller *phb, int config_addr, int option)
+{
+       int ret;
+
+       /* Reset PE through RTAS call */
+       ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
+                       config_addr, BUID_HI(phb->buid),
+                       BUID_LO(phb->buid), option);
+
+       /* If fundamental-reset not supported, try hot-reset */
+       if (option == EEH_RESET_FUNDAMENTAL &&
+           ret == -8) {
+               option = EEH_RESET_HOT;
+               ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
+                               config_addr, BUID_HI(phb->buid),
+                               BUID_LO(phb->buid), option);
+       }
+
+       /* We need reset hold or settlement delay */
+       if (option == EEH_RESET_FUNDAMENTAL ||
+           option == EEH_RESET_HOT)
+               msleep(EEH_PE_RST_HOLD_TIME);
+       else
+               msleep(EEH_PE_RST_SETTLE_TIME);
+
+       return ret;
+}
+
+/**
+ * pseries_eeh_phb_configure_bridge - Configure PCI bridges in the indicated PE
+ * @phb: PCI controller
+ * @config_adddr: the associated config address
+ *
+ * The function will be called to reconfigure the bridges included
+ * in the specified PE so that the mulfunctional PE would be recovered
+ * again.
+ */
+static int pseries_eeh_phb_configure_bridge(struct pci_controller *phb, int config_addr)
+{
+       int ret;
+       /* Waiting 0.2s maximum before skipping configuration */
+       int max_wait = 200;
+
+       while (max_wait > 0) {
+               ret = rtas_call(ibm_configure_pe, 3, 1, NULL,
+                               config_addr, BUID_HI(phb->buid),
+                               BUID_LO(phb->buid));
+
+               if (!ret)
+                       return ret;
+               if (ret < 0)
+                       break;
+
+               /*
+                * If RTAS returns a delay value that's above 100ms, cut it
+                * down to 100ms in case firmware made a mistake.  For more
+                * on how these delay values work see rtas_busy_delay_time
+                */
+               if (ret > RTAS_EXTENDED_DELAY_MIN+2 &&
+                   ret <= RTAS_EXTENDED_DELAY_MAX)
+                       ret = RTAS_EXTENDED_DELAY_MIN+2;
+
+               max_wait -= rtas_busy_delay_time(ret);
+
+               if (max_wait < 0)
+                       break;
+
+               rtas_busy_delay(ret);
+       }
+
+       pr_warn("%s: Unable to configure bridge PHB#%x-PE#%x (%d)\n",
+               __func__, phb->global_number, config_addr, ret);
+       /* PAPR defines -3 as "Parameter Error" for this function: */
+       if (ret == -3)
+               return -EINVAL;
+       else
+               return -EIO;
+}
+
 /*
  * Buffer for reporting slot-error-detail rtas calls. Its here
  * in BSS, and not dynamically alloced, so that it ends up in
@@ -96,6 +243,10 @@ static int eeh_error_buf_size;
  */
 static int pseries_eeh_init(void)
 {
+       struct pci_controller *phb;
+       struct pci_dn *pdn;
+       int addr, config_addr;
+
        /* figure out EEH RTAS function call tokens */
        ibm_set_eeh_option              = rtas_token("ibm,set-eeh-option");
        ibm_set_slot_reset              = rtas_token("ibm,set-slot-reset");
@@ -148,6 +299,22 @@ static int pseries_eeh_init(void)
        /* Set EEH machine dependent code */
        ppc_md.pcibios_bus_add_device = pseries_pcibios_bus_add_device;
 
+       if (is_kdump_kernel() || reset_devices) {
+               pr_info("Issue PHB reset ...\n");
+               list_for_each_entry(phb, &hose_list, list_node) {
+                       pdn = list_first_entry(&PCI_DN(phb->dn)->child_list, struct pci_dn, list);
+                       addr = (pdn->busno << 16) | (pdn->devfn << 8);
+                       config_addr = pseries_eeh_get_config_addr(phb, addr);
+                       /* invalid PE config addr */
+                       if (config_addr == 0)
+                               continue;
+
+                       pseries_eeh_phb_reset(phb, config_addr, EEH_RESET_FUNDAMENTAL);
+                       pseries_eeh_phb_reset(phb, config_addr, EEH_RESET_DEACTIVATE);
+                       pseries_eeh_phb_configure_bridge(phb, config_addr);
+               }
+       }
+
        return 0;
 }
 
@@ -569,35 +736,13 @@ static int pseries_eeh_get_state(struct eeh_pe *pe, int *delay)
 static int pseries_eeh_reset(struct eeh_pe *pe, int option)
 {
        int config_addr;
-       int ret;
 
        /* Figure out PE address */
        config_addr = pe->config_addr;
        if (pe->addr)
                config_addr = pe->addr;
 
-       /* Reset PE through RTAS call */
-       ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
-                       config_addr, BUID_HI(pe->phb->buid),
-                       BUID_LO(pe->phb->buid), option);
-
-       /* If fundamental-reset not supported, try hot-reset */
-       if (option == EEH_RESET_FUNDAMENTAL &&
-           ret == -8) {
-               option = EEH_RESET_HOT;
-               ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
-                               config_addr, BUID_HI(pe->phb->buid),
-                               BUID_LO(pe->phb->buid), option);
-       }
-
-       /* We need reset hold or settlement delay */
-       if (option == EEH_RESET_FUNDAMENTAL ||
-           option == EEH_RESET_HOT)
-               msleep(EEH_PE_RST_HOLD_TIME);
-       else
-               msleep(EEH_PE_RST_SETTLE_TIME);
-
-       return ret;
+       return pseries_eeh_phb_reset(pe->phb, config_addr, option);
 }
 
 /**
@@ -641,56 +786,17 @@ static int pseries_eeh_get_log(struct eeh_pe *pe, int severity, char *drv_log, u
  * pseries_eeh_configure_bridge - Configure PCI bridges in the indicated PE
  * @pe: EEH PE
  *
- * The function will be called to reconfigure the bridges included
- * in the specified PE so that the mulfunctional PE would be recovered
- * again.
  */
 static int pseries_eeh_configure_bridge(struct eeh_pe *pe)
 {
        int config_addr;
-       int ret;
-       /* Waiting 0.2s maximum before skipping configuration */
-       int max_wait = 200;
 
        /* Figure out the PE address */
        config_addr = pe->config_addr;
        if (pe->addr)
                config_addr = pe->addr;
 
-       while (max_wait > 0) {
-               ret = rtas_call(ibm_configure_pe, 3, 1, NULL,
-                               config_addr, BUID_HI(pe->phb->buid),
-                               BUID_LO(pe->phb->buid));
-
-               if (!ret)
-                       return ret;
-               if (ret < 0)
-                       break;
-
-               /*
-                * If RTAS returns a delay value that's above 100ms, cut it
-                * down to 100ms in case firmware made a mistake.  For more
-                * on how these delay values work see rtas_busy_delay_time
-                */
-               if (ret > RTAS_EXTENDED_DELAY_MIN+2 &&
-                   ret <= RTAS_EXTENDED_DELAY_MAX)
-                       ret = RTAS_EXTENDED_DELAY_MIN+2;
-
-               max_wait -= rtas_busy_delay_time(ret);
-
-               if (max_wait < 0)
-                       break;
-
-               rtas_busy_delay(ret);
-       }
-
-       pr_warn("%s: Unable to configure bridge PHB#%x-PE#%x (%d)\n",
-               __func__, pe->phb->global_number, pe->addr, ret);
-       /* PAPR defines -3 as "Parameter Error" for this function: */
-       if (ret == -3)
-               return -EINVAL;
-       else
-               return -EIO;
+       return pseries_eeh_phb_configure_bridge(pe->phb, config_addr);
 }
 
 /**