[RFC PATCH v2 02/16] ACPIHP: ACPI system device hotplug slot enumerator

[Jiang Liu <jiang.liu@huawei.com>]

From: Jiang Liu <jiang.liu@huawei.com>

The first is an ACPI hotplug slot enumerator, which enumerates ACPI hotplug
slots on load and provides callbacks to manage those hotplug slots.
An ACPI hotplug slot is an abstraction of receptacles, where a group of
system devices could be connected to. This patch implements the skeleton for
ACPI system device hotplug slot enumerator. On loading, the driver scans the
whole ACPI namespace for hotplug slots and creates a device node for each
hotplug slots. Every slot is associated with a device class named
acpihp_slot_class and will be managed by ACPI hotplug drivers.

The hotplug enumerator will create following sysfs entries for hotplug slots:

linux-drf:/sys/devices/LNXSYSTM:00/acpihp # ll
drwxr-xr-x 4 root root 0 Jul 28 16:00 NODE00
drwxr-xr-x 3 root root 0 Jul 28 16:00 NODE01
drwxr-xr-x 3 root root 0 Jul 28 16:00 NODE02

linux-drf:/sys/devices/LNXSYSTM:00/acpihp/NODE00 # ll
drwxr-xr-x 3 root root     0 Jul 28 16:00 IOX01
-r--r--r-- 1 root root 65536 Jul 28 16:01 capabilities
lrwxrwxrwx 1 root root     0 Jul 28 16:00 device -> ../../../LNXSYSTM:00
-r--r--r-- 1 root root 65536 Jul 28 16:01 object
drwxr-xr-x 2 root root     0 Jul 28 16:01 power
-r--r--r-- 1 root root 65536 Jul 28 16:01 state
-r--r--r-- 1 root root 65536 Jul 28 16:01 status
lrwxrwxrwx 1 root root     0 Jul 28 16:00 subsystem -> ../../../../class/acpihp
-r--r--r-- 1 root root 65536 Jul 28 16:01 type
-rw-r--r-- 1 root root 65536 Jul 28 16:01 uevent

linux-drf:/sys/bus/acpi/acpihp # ls
NODE00  NODE00.IOX01  NODE01  NODE02

linux-drf:/sys/bus/acpi/acpihp # ll
lrwxrwxrwx 1 root root 0 Jul 28 16:03 NODE00 ->
		../../../devices/LNXSYSTM:00/acpihp/NODE00
lrwxrwxrwx 1 root root 0 Jul 28 16:03 NODE00.IOX01 ->
		../../../devices/LNXSYSTM:00/acpihp/NODE00/IOX01
lrwxrwxrwx 1 root root 0 Jul 28 16:03 NODE01 ->
		../../../devices/LNXSYSTM:00/acpihp/NODE01
lrwxrwxrwx 1 root root 0 Jul 28 16:03 NODE02 ->
		../../../devices/LNXSYSTM:00/acpihp/NODE02

Signed-off-by: Jiang Liu <liuj97@gmail.com>
Signed-off-by: Gaohuai Han <hangaohuai@huawei.com>
---
 drivers/acpi/Kconfig             |   11 +
 drivers/acpi/hotplug/Makefile    |    3 +
 drivers/acpi/hotplug/slot_enum.c |  466 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 480 insertions(+)
 create mode 100644 drivers/acpi/hotplug/slot_enum.c

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index e457d31..711e18e 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -333,6 +333,17 @@ menuconfig ACPI_HOTPLUG
 	  If your hardware and firmware do not support adding or removing
 	  of system devices at runtime, you need not to enable this option.
 
+config ACPI_HOTPLUG_ENUM
+	tristate "ACPI Hotplug Slot Enumerator"
+	depends on ACPI_HOTPLUG
+	default y
+	help
+	  This driver enumerates ACPI hotplug slots for ACPI based system
+	  device hotplug.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called acpihp_enum.
+
 config ACPI_CONTAINER
 	tristate "Container and Module Devices (EXPERIMENTAL)"
 	depends on EXPERIMENTAL
diff --git a/drivers/acpi/hotplug/Makefile b/drivers/acpi/hotplug/Makefile
index 5e7790f..41c0da9 100644
--- a/drivers/acpi/hotplug/Makefile
+++ b/drivers/acpi/hotplug/Makefile
@@ -4,3 +4,6 @@
 
 obj-$(CONFIG_ACPI_HOTPLUG)			+= acpihp.o
 acpihp-y					= core.o
+
+obj-$(CONFIG_ACPI_HOTPLUG_ENUM)			+= acpihp_enum.o
+acpihp_enum-y					= slot_enum.o
diff --git a/drivers/acpi/hotplug/slot_enum.c b/drivers/acpi/hotplug/slot_enum.c
new file mode 100644
index 0000000..80396a3
--- /dev/null
+++ b/drivers/acpi/hotplug/slot_enum.c
@@ -0,0 +1,466 @@
+/*
+ * Copyright (C) 2011 Huawei Tech. Co., Ltd.
+ * Copyright (C) 2011 Jiang Liu <jiang.liu@huawei.com>
+ * Copyright (C) 2011 Gaohuai Han <hangaohuai@huawei.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <acpi/acpi.h>
+#include <acpi/acpi_hotplug.h>
+
+static LIST_HEAD(slot_list);
+static LIST_HEAD(slot_id_list);
+
+struct acpihp_slot_id {
+	struct list_head node;
+	unsigned long instance_id;
+	enum acpihp_slot_type type;
+};
+
+static struct acpihp_slot_ops *slot_ops_curr;
+
+/*
+ * Array of platform specific enumeration methods.
+ * Entries in the array should be sorted by descending priority order.
+ */
+static struct acpihp_slot_ops *slot_ops_array[] = {
+	NULL
+};
+
+static void acpihp_enum_cleanup_slots(void);
+
+static int __init acpihp_get_parent_slot(struct acpihp_slot *slot)
+{
+	acpi_handle handle, root_handle;
+	struct acpihp_slot *tmp;
+
+	slot->parent = NULL;
+	handle = slot->handle;
+	if (ACPI_FAILURE(acpi_get_handle(NULL, ACPI_NS_ROOT_PATH,
+			 &root_handle))) {
+		ACPIHP_WARN("fails to get ACPI root device.\n");
+		return -EINVAL;
+	}
+
+	do {
+		if (ACPI_FAILURE(acpi_get_parent(handle, &handle))) {
+			ACPIHP_DEBUG("fails to get parent device handle.\n");
+			return -ENODEV;
+		}
+		list_for_each_entry(tmp, &slot_list, slot_list)
+			if (tmp->handle == handle) {
+				slot->parent = tmp;
+				return 0;
+			}
+	} while (handle != root_handle);
+
+	return 0;
+}
+
+static int __init acpihp_get_slot_state(struct acpihp_slot *slot)
+{
+	unsigned long long sta;
+
+	/* An hotplug slot must implement _STA method. */
+	if (ACPI_FAILURE(acpi_evaluate_integer(slot->handle, METHOD_NAME__STA,
+					       NULL, &sta))) {
+		ACPIHP_DEBUG("fails to execute _STA method.\n");
+		return -EINVAL;
+	}
+
+	if (!(sta & ACPI_STA_DEVICE_PRESENT))
+		slot->state = ACPIHP_SLOT_STATE_ABSENT;
+	else if ((sta & ACPI_STA_DEVICE_ENABLED) ||
+		 (sta & ACPI_STA_DEVICE_FUNCTIONING))
+		slot->state = ACPIHP_SLOT_STATE_POWERED;
+	else
+		slot->state = ACPIHP_SLOT_STATE_PRESENT;
+
+	return 0;
+}
+
+static int __init acpihp_enum_create_slot(acpi_handle handle)
+{
+	struct acpihp_slot *slot;
+
+	slot = acpihp_create_slot(handle, "TEMP");
+	if (!slot) {
+		ACPIHP_DEBUG("fails to allocate memory for hotplug slot.\n");
+		return -ENOMEM;
+	}
+
+	slot->slot_ops = slot_ops_curr;
+
+	if (acpihp_get_parent_slot(slot))
+		goto out;
+	if (acpihp_get_slot_state(slot))
+		goto out;
+	if (ACPI_FAILURE(acpihp_slot_get_capabilities(slot,
+						      &slot->capabilities))) {
+		ACPIHP_DEBUG("fails to get slot capabilities.\n");
+		goto out;
+	}
+	if (ACPI_FAILURE(acpihp_mark_slot(handle, slot))) {
+		ACPIHP_DEBUG("fails to attach slot to ACPI device object.\n");
+		goto out;
+	}
+
+	list_add_tail(&slot->slot_list, &slot_list);
+
+	return 0;
+out:
+	acpihp_slot_put(slot);
+	return -EINVAL;
+}
+
+/*
+ * Scan hotplug slots for ACPI based system device hotplug.
+ * We only care about processor, memory, PCI host bridge and CONTAINER.
+ */
+static acpi_status __init acpihp_enum_scan_slot(acpi_handle handle, u32 lvl,
+						void *context, void **rv)
+{
+	enum acpihp_dev_type type;
+
+	if (acpihp_dev_get_type(handle, &type) ||
+	    type == ACPIHP_DEV_TYPE_UNKNOWN)
+		return AE_OK;
+
+	if (ACPI_SUCCESS(slot_ops_curr->check(handle)))
+		acpihp_enum_create_slot(handle);
+
+	/*
+	 * Don't scan hotplug slots under PCI host bridges, they should be
+	 * handled by acpiphp or pciehp drivers.
+	 */
+	if (type == ACPIHP_DEV_TYPE_HOST_BRIDGE)
+		return AE_CTRL_DEPTH;
+
+	return AE_OK;
+}
+
+/*
+ * Get types of child devices connected to this slot.
+ * We only care about CPU, memory, PCI host bridge and CONTAINER here.
+ * Values used here must be in consistence with acpihp_enum_get_slot_type().
+ */
+static acpi_status __init
+acpihp_enum_get_dev_type(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+	acpi_status status = AE_OK;
+	enum acpihp_dev_type type;
+	u32 *tp = (u32 *)rv;
+
+	if (!acpihp_dev_get_type(handle, &type)) {
+		switch (type) {
+		case ACPIHP_DEV_TYPE_CPU:
+			*tp |= 0x0001;
+			status = AE_CTRL_DEPTH;
+			break;
+		case ACPIHP_DEV_TYPE_MEM:
+			*tp |= 0x0002;
+			status = AE_CTRL_DEPTH;
+			break;
+		case ACPIHP_DEV_TYPE_HOST_BRIDGE:
+			*tp |= 0x0004;
+			status = AE_CTRL_DEPTH;
+			break;
+		case ACPIHP_DEV_TYPE_CONTAINER:
+			*tp |= 0x0008;
+			break;
+		default:
+			break;
+		}
+	}
+
+	return status;
+}
+
+/*
+ * Guess type of a hotplug slot according to child devices connecting to it.
+ */
+static enum acpihp_slot_type __init acpihp_enum_get_slot_type(u32 dev_types)
+{
+	BUG_ON(dev_types > 15);
+
+	switch (dev_types) {
+	case 0:
+		/* Generic CONTAINER */
+		return ACPIHP_SLOT_TYPE_COMMON;
+	case 1:
+		/* Physical processor with logical CPUs */
+		return ACPIHP_SLOT_TYPE_CPU;
+	case 2:
+		/* Memory board/box with memory devices */
+		return ACPIHP_SLOT_TYPE_MEM;
+	case 3:
+		/* Physical processor with CPUs and memory controllers */
+		return ACPIHP_SLOT_TYPE_CPU;
+	case 4:
+		/* IO eXtension board/box with IO host bridges */
+		return ACPIHP_SLOT_TYPE_IOX;
+	case 7:
+		/* Physical processor with CPUs, IO host bridges and MCs. */
+		return ACPIHP_SLOT_TYPE_CPU;
+	case 8:
+		/* Generic CONTAINER */
+		return ACPIHP_SLOT_TYPE_COMMON;
+	case 9:
+		/* System board with physical processors */
+		return ACPIHP_SLOT_TYPE_SYSTEM_BOARD;
+	case 11:
+		/* System board with physical processors and memory */
+		return ACPIHP_SLOT_TYPE_SYSTEM_BOARD;
+	case 15:
+		/* Node with processor, memory and IO host bridge */
+		return ACPIHP_SLOT_TYPE_NODE;
+	default:
+		return ACPIHP_SLOT_TYPE_UNKNOWN;
+	}
+}
+
+/*
+ * Guess type of a hotplug slot according to the device type of the
+ * corresponding ACPI object itself.
+ */
+static enum acpihp_slot_type __init
+acpihp_enum_check_slot_self(struct acpihp_slot *slot)
+{
+	enum acpihp_dev_type type;
+
+	if (acpihp_dev_get_type(slot->handle, &type))
+		return ACPIHP_SLOT_TYPE_UNKNOWN;
+
+	switch (type) {
+	case ACPIHP_DEV_TYPE_CPU:
+		/* Logical CPU used in virtualization environment */
+		return ACPIHP_SLOT_TYPE_CPU;
+	case ACPIHP_DEV_TYPE_MEM:
+		/* Memory board with single memory device */
+		return ACPIHP_SLOT_TYPE_MEM;
+	case ACPIHP_DEV_TYPE_HOST_BRIDGE:
+		/* IO eXtension board/box with single IO host bridge */
+		return ACPIHP_SLOT_TYPE_IOX;
+	default:
+		return ACPIHP_SLOT_TYPE_UNKNOWN;
+	}
+}
+
+static int __init acpihp_enum_generate_slot_name(struct acpihp_slot *slot)
+{
+	int found = 0;
+	struct list_head *list;
+	struct acpihp_slot_id *slot_id;
+	unsigned long long uid;
+
+	/* Respect firmware settings if _UID return an integer. */
+	if (ACPI_SUCCESS(acpi_evaluate_integer(slot->handle, METHOD_NAME__UID,
+					       NULL, &uid)))
+		goto set_name;
+
+	if (slot->parent)
+		list = &slot->parent->slot_id_list;
+	else
+		list = &slot_id_list;
+
+	list_for_each_entry(slot_id, list, node)
+		if (slot_id->type == slot->type) {
+			found = 1;
+			break;
+		}
+	if (!found) {
+		slot_id = kzalloc(sizeof(struct acpihp_slot_id), GFP_KERNEL);
+		if (!slot_id) {
+			ACPIHP_DEBUG("fails to allocate slot instance ID.\n");
+			return -ENOMEM;
+		}
+		slot_id->type = slot->type;
+		list_add_tail(&slot_id->node, list);
+	}
+
+	uid = slot_id->instance_id++;
+
+set_name:
+	snprintf(slot->name, sizeof(slot->name) - 1, "%s%02llx",
+		 acpihp_get_slot_type_name(slot->type), uid);
+	dev_set_name(&slot->dev, "%s", slot->name);
+
+	return 0;
+}
+
+/*
+ * Generate a meaningful name for the slot according to devices connecting
+ * to this slot
+ */
+static int __init acpihp_enum_rename_slot(struct acpihp_slot *slot)
+{
+	u32 child_types = 0;
+
+	slot->type = acpihp_enum_check_slot_self(slot);
+	if (slot->type == ACPIHP_SLOT_TYPE_UNKNOWN) {
+		acpi_walk_namespace(ACPI_TYPE_DEVICE, slot->handle,
+				ACPI_UINT32_MAX, acpihp_enum_get_dev_type,
+				NULL, NULL, (void **)&child_types);
+		acpi_walk_namespace(ACPI_TYPE_PROCESSOR, slot->handle,
+				ACPI_UINT32_MAX, acpihp_enum_get_dev_type,
+				NULL, NULL, (void **)&child_types);
+		slot->type = acpihp_enum_get_slot_type(child_types);
+	}
+
+	if (acpihp_enum_generate_slot_name(slot))
+		return -EINVAL;
+
+	return 0;
+}
+
+static void __init acpihp_enum_rename_and_register_slots(void)
+{
+	struct acpihp_slot *slot;
+
+	list_for_each_entry(slot, &slot_list, slot_list) {
+		/* generate a meaningful name for this slot */
+		if (acpihp_enum_rename_slot(slot))
+			continue;
+
+		if (acpihp_register_slot(slot))
+			ACPIHP_DEBUG("fails to register slot %s.\n",
+				     slot->name);
+	}
+}
+
+static int __init acpihp_enum_generate_slots(void)
+{
+	acpi_status status;
+
+	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+				     ACPI_UINT32_MAX, acpihp_enum_scan_slot,
+				     NULL, NULL, NULL);
+	if (!ACPI_SUCCESS(status))
+		goto out_err;
+
+	status = acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
+				     ACPI_UINT32_MAX, acpihp_enum_scan_slot,
+				     NULL, NULL, NULL);
+	if (!ACPI_SUCCESS(status))
+		goto out_err;
+
+	acpihp_enum_rename_and_register_slots();
+
+	return 0;
+
+out_err:
+	ACPIHP_DEBUG("fails to scan hotplug slots.\n");
+	acpihp_enum_cleanup_slots();
+
+	return -ENOTSUPP;
+}
+
+static void acpihp_enum_unregister_slots(void)
+{
+	struct acpihp_slot *slot, *tmp;
+	struct acpihp_slot_id *slot_id, *slot_id_safe;
+
+	list_for_each_entry_safe(slot, tmp, &slot_list, slot_list) {
+		acpihp_unregister_slot(slot);
+		list_del_init(&slot->slot_list);
+		acpihp_unmark_slot(slot->handle);
+		list_for_each_entry_safe(slot_id, slot_id_safe,
+					 &slot->slot_id_list, node) {
+			list_del(&slot_id->node);
+			kfree(slot_id);
+		}
+		acpihp_slot_put(slot);
+	}
+}
+
+static void acpihp_enum_cleanup_slots(void)
+{
+	struct acpihp_slot_id *slot_id, *tmp;
+
+	acpihp_enum_unregister_slots();
+	list_for_each_entry_safe(slot_id, tmp, &slot_id_list, node) {
+		list_del(&slot_id->node);
+		kfree(slot_id);
+	}
+}
+
+static int __init acpihp_enum_init(void)
+{
+	int i;
+	int retval;
+
+	/* probe for suitable enumerator. */
+	for (i = 0; slot_ops_array[i]; i++)
+		if (ACPI_SUCCESS(slot_ops_array[i]->init())) {
+			slot_ops_curr = slot_ops_array[i];
+			break;
+		}
+	if (slot_ops_curr == NULL) {
+		ACPIHP_DEBUG("no ACPI hotplug slot found.\n");
+		return -ENXIO;
+	}
+
+	retval = acpihp_register_class();
+	if (retval != 0) {
+		ACPIHP_DEBUG("fails to register ACPI hotplug slot class.\n");
+		goto out_fini;
+	}
+
+	retval = acpihp_enum_generate_slots();
+	if (retval != 0) {
+		ACPIHP_DEBUG("fails to enumerate ACPI hotplug slots.\n");
+		goto out_unregister_class;
+	}
+
+	/* Back out if no ACPI hotplug slot  found. */
+	if (list_empty(&slot_list)) {
+		ACPIHP_DEBUG("no ACPI hotplug slot found.\n");
+		retval = -ENODEV;
+		goto out_unregister_class;
+	}
+
+	return 0;
+
+out_unregister_class:
+	acpihp_unregister_class();
+out_fini:
+	slot_ops_curr->fini();
+	ACPIHP_DEBUG("fails to initialize hotplug slot enumerator.\n");
+
+	return retval;
+}
+
+static void __exit acpihp_enum_exit(void)
+{
+	acpihp_enum_cleanup_slots();
+	acpihp_unregister_class();
+	slot_ops_curr->fini();
+}
+
+module_init(acpihp_enum_init);
+module_exit(acpihp_enum_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Jiang Liu <jiang.liu@huawei.com>");
+MODULE_AUTHOR("Gaohuai Han <hangaohuai@huawei.com>");
-- 
1.7.9.5