[POWERPC] Add powerpc PCI-E reset API implementation

Adds the pSeries platform implementation for a new PCI API
which can be used to issue various types of PCI-E reset,
including PCI-E warm reset and PCI-E hot reset. This is needed
for an ipr PCI-E adapter which does not properly implement BIST.
Running BIST on this adapter results in PCI-E errors. The only
reliable reset mechanism that exists on this hardware is PCI
Fundamental reset (warm reset).

Acked-by: Linas Vepstas <[e-mail]>
Signed-off-by: Brian King <[e-mail]>
Signed-off-by: Paul Mackerras <[e-mail]>

arch/powerpc/platforms/pseries/eeh.c

···
 }
 
 /**
+ * pcibios_set_pcie_slot_reset - Set PCI-E reset state
+ * @dev:	pci device struct
+ * @state:	reset state to enter
+ *
+ * Return value:
+ * 	0 if success
+ **/
+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:
+		rtas_pci_slot_reset(pdn, 0);
+		break;
+	case pcie_hot_reset:
+		rtas_pci_slot_reset(pdn, 1);
+		break;
+	case pcie_warm_reset:
+		rtas_pci_slot_reset(pdn, 3);
+		break;
+	default:
+		return -EINVAL;
+	};
+
+	return 0;
+}
+
+/**
  * rtas_set_slot_reset -- assert the pci #RST line for 1/4 second
  * @pdn: pci device node to be reset.
  *