[RFC PATCH v2 01/12] Add sys_hotplug.h for system device hotplug framework

[Toshi Kani]

Added include/linux/sys_hotplug.h, which defines the system device
hotplug framework interfaces used by the framework itself and
handlers.

The order values define the calling sequence of handlers.  For add
execute, the ordering is ACPI->MEM->CPU.  Memory is onlined before
CPU so that threads on new CPUs can start using their local memory.
The ordering of the delete execute is symmetric to the add execute.

struct shp_request defines a hot-plug request information.  The
device resource information is managed with a list so that a single
request may target to multiple devices.

Signed-off-by: Toshi Kani <toshi.kani at hp.com>
---
 include/linux/sys_hotplug.h |  181 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 181 insertions(+)
 create mode 100644 include/linux/sys_hotplug.h

diff --git a/include/linux/sys_hotplug.h b/include/linux/sys_hotplug.h
new file mode 100644
index 0000000..86674dd
--- /dev/null
+++ b/include/linux/sys_hotplug.h
@@ -0,0 +1,181 @@
+/*
+ * sys_hotplug.h - System device hot-plug framework
+ *
+ * Copyright (C) 2012 Hewlett-Packard Development Company, L.P.
+ *	Toshi Kani <toshi.kani at hp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _LINUX_SYS_HOTPLUG_H
+#define _LINUX_SYS_HOTPLUG_H
+
+#include <linux/list.h>
+#include <linux/device.h>
+
+/*
+ * System device hot-plug operation proceeds in the following order.
+ *   Validate phase -> Execute phase -> Commit phase
+ *
+ * The order values below define the calling sequence of platform
+ * neutral handlers for each phase in ascending order.  The order
+ * values of firmware-specific handlers are defined in sys_hotplug.h
+ * under firmware specific directories.
+ */
+
+/* All order values must be smaller than this value */
+#define SHP_ORDER_MAX				0xffffff
+
+/* Add Validate order values */
+
+/* Add Execute order values */
+#define SHP_MEM_ADD_EXECUTE_ORDER		100
+#define SHP_CPU_ADD_EXECUTE_ORDER		110
+
+/* Add Commit order values */
+
+/* Delete Validate order values */
+#define SHP_CPU_DEL_VALIDATE_ORDER		100
+#define SHP_MEM_DEL_VALIDATE_ORDER		110
+
+/* Delete Execute order values */
+#define SHP_CPU_DEL_EXECUTE_ORDER		10
+#define SHP_MEM_DEL_EXECUTE_ORDER		20
+
+/* Delete Commit order values */
+
+/*
+ * Hot-plug request types
+ */
+#define SHP_REQ_ADD		0x000000
+#define SHP_REQ_DELETE		0x000001
+#define SHP_REQ_MASK		0x0000ff
+
+/*
+ * Hot-plug phase types
+ */
+#define SHP_PH_VALIDATE		0x000000
+#define SHP_PH_EXECUTE		0x000100
+#define SHP_PH_COMMIT		0x000200
+#define SHP_PH_MASK		0x00ff00
+
+/*
+ * Hot-plug operation types
+ */
+#define SHP_OP_HOTPLUG		0x000000
+#define SHP_OP_ONLINE		0x010000
+#define SHP_OP_MASK		0xff0000
+
+/*
+ * Hot-plug phases
+ */
+enum shp_phase {
+	SHP_ADD_VALIDATE	= (SHP_REQ_ADD|SHP_PH_VALIDATE),
+	SHP_ADD_EXECUTE		= (SHP_REQ_ADD|SHP_PH_EXECUTE),
+	SHP_ADD_COMMIT		= (SHP_REQ_ADD|SHP_PH_COMMIT),
+	SHP_DEL_VALIDATE	= (SHP_REQ_DELETE|SHP_PH_VALIDATE),
+	SHP_DEL_EXECUTE		= (SHP_REQ_DELETE|SHP_PH_EXECUTE),
+	SHP_DEL_COMMIT		= (SHP_REQ_DELETE|SHP_PH_COMMIT)
+};
+
+/*
+ * Hot-plug operations
+ */
+enum shp_operation {
+	SHP_HOTPLUG_ADD		= (SHP_OP_HOTPLUG|SHP_REQ_ADD),
+	SHP_HOTPLUG_DEL		= (SHP_OP_HOTPLUG|SHP_REQ_DELETE),
+	SHP_ONLINE_ADD		= (SHP_OP_ONLINE|SHP_REQ_ADD),
+	SHP_ONLINE_DEL		= (SHP_OP_ONLINE|SHP_REQ_DELETE)
+};
+
+/*
+ * Hot-plug device classes
+ */
+enum shp_class {
+	SHP_CLS_INVALID		= 0,
+	SHP_CLS_CPU		= 1,
+	SHP_CLS_MEMORY		= 2,
+	SHP_CLS_HOSTBRIDGE	= 3,
+	SHP_CLS_CONTAINER	= 4,
+};
+
+/*
+ * Hot-plug device information
+ */
+union shp_dev_info {
+	struct shp_cpu {
+		u32		cpu_id;
+	} cpu;
+
+	struct shp_memory {
+		int		node;
+		u64		start_addr;
+		u64		length;
+	} mem;
+
+	struct shp_hostbridge {
+	} hb;
+
+	struct shp_node {
+	} node;
+};
+
+struct shp_device {
+	struct list_head	list;
+	struct device		*device;
+	enum shp_class		class;
+	union shp_dev_info	info;
+};
+
+/*
+ * Hot-plug request
+ */
+struct shp_request {
+	/* common info */
+	enum shp_operation	operation;	/* operation */
+
+	/* hot-plug event info: only valid for hot-plug operations */
+	void			*handle;	/* FW handle */
+	u32			event;		/* FW event */
+
+	/* device resource info */
+	struct list_head	dev_list;	/* shp_device list */
+};
+
+/*
+ * Inline Utility Functions
+ */
+static inline bool shp_is_hotplug_op(enum shp_operation operation)
+{
+	return (operation & SHP_OP_MASK) == SHP_OP_HOTPLUG;
+}
+
+static inline bool shp_is_online_op(enum shp_operation operation)
+{
+	return (operation & SHP_OP_MASK) == SHP_OP_ONLINE;
+}
+
+static inline bool shp_is_add_op(enum shp_operation operation)
+{
+	return (operation & SHP_REQ_MASK) == SHP_REQ_ADD;
+}
+
+static inline bool shp_is_add_phase(enum shp_phase phase)
+{
+	return (phase & SHP_REQ_MASK) == SHP_REQ_ADD;
+}
+
+/*
+ * Externs
+ */
+typedef int (*shp_func)(struct shp_request *req, int rollback);
+extern int shp_register_handler(enum shp_phase phase, shp_func func, u32 order);
+extern int shp_unregister_handler(enum shp_phase phase, shp_func func);
+extern int shp_submit_req(struct shp_request *req);
+extern struct shp_request *shp_alloc_request(enum shp_operation operation);
+extern void shp_add_dev_info(struct shp_request *shp_req,
+		struct shp_device *shp_dev);
+
+#endif	/* _LINUX_SYS_HOTPLUG_H */