powerpc/eeh: pseries platform EEH reset PE

On RTAS compliant pSeries platform, there is a dedicated RTAS call
(ibm,set-slot-reset) to reset the specified PE. Furthermore, two
types of resets are supported: hot and fundamental. the type of
reset is to be used actually depends on the included PCI device's
requirements.

The patch implements resetting PE on pSeries platform through RTAS
call. Besides, it has been abstracted through struct eeh_ops::reset
so that EEH core components could support multiple platforms in future.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/eeh.h

@@ -49,6 +49,9 @@ struct device_node;
 #define EEH_STATE_DMA_ACTIVE	(1 << 4)	/* Active DMA		*/
 #define EEH_STATE_MMIO_ENABLED	(1 << 5)	/* MMIO enabled		*/
 #define EEH_STATE_DMA_ENABLED	(1 << 6)	/* DMA enabled		*/
+#define EEH_RESET_DEACTIVATE	0	/* Deactivate the PE reset	*/
+#define EEH_RESET_HOT		1	/* Hot reset			*/
+#define EEH_RESET_FUNDAMENTAL	3	/* Fundamental reset		*/
 
 struct eeh_ops {
 	char *name;

arch/powerpc/platforms/pseries/eeh.c

@@ -87,7 +87,6 @@
 #define PCI_BUS_RESET_WAIT_MSEC (60*1000)
 
 /* RTAS tokens */
-static int ibm_set_slot_reset;
 static int ibm_slot_error_detail;
 static int ibm_configure_bridge;
 static int ibm_configure_pe;
@@ -606,54 +605,6 @@ int eeh_pci_enable(struct pci_dn *pdn, int function)
 	return rc;
 }
 
-/**
- * eeh_slot_reset - Raises/Lowers the pci #RST line
- * @pdn: pci device node
- * @state: 1/0 to raise/lower the #RST
- *
- * Clear the EEH-frozen condition on a slot.  This routine
- * asserts the PCI #RST line if the 'state' argument is '1',
- * and drops the #RST line if 'state is '0'.  This routine is
- * safe to call in an interrupt context.
- */
-static void eeh_slot_reset(struct pci_dn *pdn, int state)
-{
-	int config_addr;
-	int rc;
-
-	BUG_ON(pdn==NULL);
-
-	if (!pdn->phb) {
-		printk(KERN_WARNING "EEH: in slot reset, device node %s has no phb\n",
-		        pdn->node->full_name);
-		return;
-	}
-
-	/* Use PE configuration address, if present */
-	config_addr = pdn->eeh_config_addr;
-	if (pdn->eeh_pe_config_addr)
-		config_addr = pdn->eeh_pe_config_addr;
-
-	rc = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
-	               config_addr,
-	               BUID_HI(pdn->phb->buid),
-	               BUID_LO(pdn->phb->buid),
-	               state);
-
-	/* Fundamental-reset not supported on this PE, try hot-reset */
-	if (rc == -8 && state == 3) {
-		rc = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
-			       config_addr,
-			       BUID_HI(pdn->phb->buid),
-			       BUID_LO(pdn->phb->buid), 1);
-		if (rc)
-			printk(KERN_WARNING
-				"EEH: Unable to reset the failed slot,"
-				" #RST=%d dn=%s\n",
-				rc, pdn->node->full_name);
-	}
-}
-
 /**
  * pcibios_set_pcie_slot_reset - Set PCI-E reset state
  * @dev: pci device struct
@@ -665,17 +616,16 @@ static void eeh_slot_reset(struct pci_dn *pdn, int state)
 int pcibios_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
 {
 	struct device_node *dn = pci_device_to_OF_node(dev);
-	struct pci_dn *pdn = PCI_DN(dn);
 
 	switch (state) {
 	case pcie_deassert_reset:
-		eeh_slot_reset(pdn, 0);
+		eeh_ops->reset(dn, EEH_RESET_DEACTIVATE);
 		break;
 	case pcie_hot_reset:
-		eeh_slot_reset(pdn, 1);
+		eeh_ops->reset(dn, EEH_RESET_HOT);
 		break;
 	case pcie_warm_reset:
-		eeh_slot_reset(pdn, 3);
+		eeh_ops->reset(dn, EEH_RESET_FUNDAMENTAL);
 		break;
 	default:
 		return -EINVAL;
@@ -754,9 +704,9 @@ static void eeh_reset_pe_once(struct pci_dn *pdn)
 	eeh_set_pe_freset(pdn->node, &freset);
 
 	if (freset)
-		eeh_slot_reset(pdn, 3);
+		eeh_ops->reset(pdn->node, EEH_RESET_FUNDAMENTAL);
 	else
-		eeh_slot_reset(pdn, 1);
+		eeh_ops->reset(pdn->node, EEH_RESET_HOT);
 
 	/* The PCI bus requires that the reset be held high for at least
 	 * a 100 milliseconds. We wait a bit longer 'just in case'.
@@ -770,7 +720,7 @@ static void eeh_reset_pe_once(struct pci_dn *pdn)
 	 */
 	eeh_clear_slot(pdn->node, EEH_MODE_ISOLATED);
 
-	eeh_slot_reset(pdn, 0);
+	eeh_ops->reset(pdn->node, EEH_RESET_DEACTIVATE);
 
 	/* After a PCI slot has been reset, the PCI Express spec requires
 	 * a 1.5 second idle time for the bus to stabilize, before starting
@@ -1127,7 +1077,6 @@ void __init eeh_init(void)
 	if (np == NULL)
 		return;
 
-	ibm_set_slot_reset = rtas_token("ibm,set-slot-reset");
 	ibm_slot_error_detail = rtas_token("ibm,slot-error-detail");
 	ibm_configure_bridge = rtas_token("ibm,configure-bridge");
 	ibm_configure_pe = rtas_token("ibm,configure-pe");

arch/powerpc/platforms/pseries/eeh_pseries.c

@@ -318,7 +318,30 @@ static int pseries_eeh_get_state(struct device_node *dn, int *state)
  */
 static int pseries_eeh_reset(struct device_node *dn, int option)
 {
-	return 0;
+	struct pci_dn *pdn;
+	int config_addr;
+	int ret;
+
+	/* Figure out PE address */
+	pdn = PCI_DN(dn);
+	config_addr = pdn->eeh_config_addr;
+	if (pdn->eeh_pe_config_addr)
+		config_addr = pdn->eeh_pe_config_addr;
+
+	/* Reset PE through RTAS call */
+	ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
+			config_addr, BUID_HI(pdn->phb->buid),
+			BUID_LO(pdn->phb->buid), option);
+
+	/* If fundamental-reset not supported, try hot-reset */
+	if (option == EEH_RESET_FUNDAMENTAL &&
+	    ret == -8) {
+		ret = rtas_call(ibm_set_slot_reset, 4, 1, NULL,
+				config_addr, BUID_HI(pdn->phb->buid),
+				BUID_LO(pdn->phb->buid), EEH_RESET_HOT);
+	}
+
+	return ret;
 }
 
 /**