[POWERPC] EEH: support MMIO enable recovery step

Update to the PowerPC PCI error recovery code.

Add code to enable MMIO if a device driver reports that it is capable
of recovering on its own.  One anticipated use of this having a device
driver enable MMIO so that it can take a register dump, which might
then be followed by the device driver requesting a full reset.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 64 insertions, 17 deletions

diff --git a/arch/powerpc/platforms/pseries/eeh_driver.c b/arch/powerpc/platforms/pseries/eeh_driver.c
index 045cd7a37339..c2bc9904f1cb 100644
--- a/arch/powerpc/platforms/pseries/eeh_driver.c
+++ b/arch/powerpc/platforms/pseries/eeh_driver.c
@@ -100,14 +100,38 @@ static void eeh_report_error(struct pci_dev *dev, void *userdata)
                 PCI_DN(dn)->eeh_mode |= EEH_MODE_IRQ_DISABLED;
                 disable_irq_nosync(dev->irq);
         }
-        if (!driver->err_handler)
-                return;
-        if (!driver->err_handler->error_detected)
+        if (!driver->err_handler ||
+            !driver->err_handler->error_detected)
                 return;
 
         rc = driver->err_handler->error_detected (dev, pci_channel_io_frozen);
         if (*res == PCI_ERS_RESULT_NONE) *res = rc;
-        if (*res == PCI_ERS_RESULT_NEED_RESET) return;
+        if (*res == PCI_ERS_RESULT_DISCONNECT &&
+             rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
+}
+
+/**
+ * eeh_report_mmio_enabled - tell drivers that MMIO has been enabled
+ *
+ * Report an EEH error to each device driver, collect up and
+ * merge the device driver responses. Cumulative response
+ * passed back in "userdata".
+ */
+
+static void eeh_report_mmio_enabled(struct pci_dev *dev, void *userdata)
+{
+        enum pci_ers_result rc, *res = userdata;
+        struct pci_driver *driver = dev->driver;
+
+        // dev->error_state = pci_channel_mmio_enabled;
+
+        if (!driver ||
+            !driver->err_handler ||
+            !driver->err_handler->mmio_enabled)
+                return;
+
+        rc = driver->err_handler->mmio_enabled (dev);
+        if (*res == PCI_ERS_RESULT_NONE) *res = rc;
         if (*res == PCI_ERS_RESULT_DISCONNECT &&
              rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
 }
@@ -118,6 +142,7 @@ static void eeh_report_error(struct pci_dev *dev, void *userdata)
 
 static void eeh_report_reset(struct pci_dev *dev, void *userdata)
 {
+        enum pci_ers_result rc, *res = userdata;
         struct pci_driver *driver = dev->driver;
         struct device_node *dn = pci_device_to_OF_node(dev);
 
@@ -128,12 +153,14 @@ static void eeh_report_reset(struct pci_dev *dev, void *userdata)
                 PCI_DN(dn)->eeh_mode &= ~EEH_MODE_IRQ_DISABLED;
                 enable_irq(dev->irq);
         }
-        if (!driver->err_handler)
-                return;
-        if (!driver->err_handler->slot_reset)
+        if (!driver->err_handler ||
+            !driver->err_handler->slot_reset)
                 return;
 
-        driver->err_handler->slot_reset(dev);
+        rc = driver->err_handler->slot_reset(dev);
+        if (*res == PCI_ERS_RESULT_NONE) *res = rc;
+        if (*res == PCI_ERS_RESULT_DISCONNECT &&
+             rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
 }
 
 /**
@@ -362,23 +389,43 @@ struct pci_dn * handle_eeh_events (struct eeh_event *event)
                         goto hard_fail;
         }
 
-        /* If any device called out for a reset, then reset the slot */
-        if (result == PCI_ERS_RESULT_NEED_RESET) {
-                rc = eeh_reset_device(frozen_pdn, NULL);
-                if (rc)
-                        goto hard_fail;
-                pci_walk_bus(frozen_bus, eeh_report_reset, NULL);
+        /* If all devices reported they can proceed, then re-enable MMIO */
+        if (result == PCI_ERS_RESULT_CAN_RECOVER) {
+                rc = rtas_pci_enable(frozen_pdn, EEH_THAW_MMIO);
+
+                if (rc) {
+                        result = PCI_ERS_RESULT_NEED_RESET;
+                } else {
+                        result = PCI_ERS_RESULT_NONE;
+                        pci_walk_bus(frozen_bus, eeh_report_mmio_enabled, &result);
+                }
         }
 
-        /* If all devices reported they can proceed, the re-enable PIO */
+        /* If all devices reported they can proceed, then re-enable DMA */
         if (result == PCI_ERS_RESULT_CAN_RECOVER) {
-                /* XXX Not supported; we brute-force reset the device */
+                rc = rtas_pci_enable(frozen_pdn, EEH_THAW_DMA);
+
+                if (rc)
+                        result = PCI_ERS_RESULT_NEED_RESET;
+        }
+
+        /* If any device has a hard failure, then shut off everything. */
+        if (result == PCI_ERS_RESULT_DISCONNECT)
+                goto hard_fail;
+
+        /* If any device called out for a reset, then reset the slot */
+        if (result == PCI_ERS_RESULT_NEED_RESET) {
                 rc = eeh_reset_device(frozen_pdn, NULL);
                 if (rc)
                         goto hard_fail;
-                pci_walk_bus(frozen_bus, eeh_report_reset, NULL);
+                result = PCI_ERS_RESULT_NONE;
+                pci_walk_bus(frozen_bus, eeh_report_reset, &result);
         }
 
+        /* All devices should claim they have recovered by now. */
+        if (result != PCI_ERS_RESULT_RECOVERED)
+                goto hard_fail;
+
         /* Tell all device drivers that they can resume operations */
         pci_walk_bus(frozen_bus, eeh_report_resume, NULL);