powerpc/eeh: Introduce eeh_pe struct

As defined in PAPR 2.4, Partitionable Endpoint (PE) is an I/O subtree
that can be treated as a unit for the purposes of partitioning and error
recovery. Therefore, eeh core should be aware of PE. With eeh_pe struct,
we can support PE explicitly. Further more, it makes all the stuff much
more data centralized. Another important reason is for eeh core to support
multiple platforms. Some of them like pSeries figures out PEs through
OF nodes while others like powernv have to do that through PCI bus/device
tree. With explicit PE support, eeh core will be implemented based on
the centrialized data and platform dependent implementations figure it
out by their feasible ways.

When the struct is designed, following factors are taken in account:
  * Reflecting the relationships of PEs. PE might have parent
    as well children.
  * Reflecting the association of PE and (eeh) devices.
  * PEs have PHB boundary.
  * PE should have unique address assigned in the corresponding
    PHB domain.

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

@@ -31,6 +31,42 @@ struct device_node;
 
 #ifdef CONFIG_EEH
 
+/*
+ * The struct is used to trace PE related EEH functionality.
+ * In theory, there will have one instance of the struct to
+ * be created against particular PE. In nature, PEs corelate
+ * to each other. the struct has to reflect that hierarchy in
+ * order to easily pick up those affected PEs when one particular
+ * PE has EEH errors.
+ *
+ * Also, one particular PE might be composed of PCI device, PCI
+ * bus and its subordinate components. The struct also need ship
+ * the information. Further more, one particular PE is only meaingful
+ * in the corresponding PHB. Therefore, the root PEs should be created
+ * against existing PHBs in on-to-one fashion.
+ */
+#define EEH_PE_PHB	1	/* PHB PE    */
+#define EEH_PE_DEVICE 	2	/* Device PE */
+#define EEH_PE_BUS	3	/* Bus PE    */
+
+#define EEH_PE_ISOLATED		(1 << 0)	/* Isolated PE		*/
+#define EEH_PE_RECOVERING	(1 << 1)	/* Recovering PE	*/
+
+struct eeh_pe {
+	int type;			/* PE type: PHB/Bus/Device	*/
+	int state;			/* PE EEH dependent mode	*/
+	int config_addr;		/* Traditional PCI address	*/
+	int addr;			/* PE configuration address	*/
+	struct pci_controller *phb;	/* Associated PHB		*/
+	int check_count;		/* Times of ignored error	*/
+	int freeze_count;		/* Times of froze up		*/
+	int false_positives;		/* Times of reported #ff's	*/
+	struct eeh_pe *parent;		/* Parent PE			*/
+	struct list_head child_list;	/* Link PE to the child list	*/
+	struct list_head edevs;		/* Link list of EEH devices	*/
+	struct list_head child;		/* Child PEs			*/
+};
+
 /*
  * The struct is used to trace EEH state for the associated
  * PCI device node or PCI device. In future, it might
@@ -53,6 +89,8 @@ struct eeh_dev {
 	int freeze_count;		/* Times of froze up		*/
 	int false_positives;		/* Times of reported #ff's	*/
 	u32 config_space[16];		/* Saved PCI config space	*/
+	struct eeh_pe *pe;		/* Associated PE		*/
+	struct list_head list;		/* Form link list in the PE	*/
 	struct pci_controller *phb;	/* Associated PHB		*/
 	struct device_node *dn;		/* Associated device node	*/
 	struct pci_dev *pdev;		/* Associated PCI device	*/