[RFC PATCH v3 11/28] ACPIHP: implement skeleton of ACPI system device hotplug driver

[Jiang Liu <liuj97@gmail.com>]

This patch implements the skeleton of the ACPI based system device
hotplug driver. This driver implements a class driver and registers
it onto acpihp_slot_class to manage all ACPI hotplug slots.

This is a platform independent driver, which implements a state machine
for hotplug slot and provides sysfs user interfaces to access hotplug
functionalities. It depends on the platform specific slot enumerator
driver to control individual hotplug slot and ACPI container, processor,
memory and PCI host bridge drivers to configure/unconfigure individual
ACPI devices.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
---
 drivers/acpi/Kconfig              |   15 ++
 drivers/acpi/hotplug/Makefile     |    3 +
 drivers/acpi/hotplug/acpihp_drv.h |   62 +++++++
 drivers/acpi/hotplug/drv_main.c   |  346 +++++++++++++++++++++++++++++++++++++
 4 files changed, 426 insertions(+)
 create mode 100644 drivers/acpi/hotplug/acpihp_drv.h
 create mode 100644 drivers/acpi/hotplug/drv_main.c

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 5a5a3e5..1f972f0 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -357,6 +357,21 @@ config ACPI_HOTPLUG_SLOT_FAKE
 	  could be used to test hotplug functionalities on hardware platforms
 	  with out system device hotplug capabilities.
 
+config ACPI_HOTPLUG_DRIVER
+	tristate "ACPI Based System Device Hotplug Driver"
+	depends on ACPI_HOTPLUG
+	default y
+	help
+	  This driver implements a framework to manage ACPI system device
+	  hotplug slots, which could be used to support hotplug of processor,
+	  memory, PCI host bridge and computner node etc.
+
+	  It depends on ACPI container, processor, memory and PCI host bridge
+	  drivers to configure/unconfigure individual ACPI devices.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called acpihp_drv.
+
 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 6e5daf6..6257047 100644
--- a/drivers/acpi/hotplug/Makefile
+++ b/drivers/acpi/hotplug/Makefile
@@ -9,3 +9,6 @@ obj-$(CONFIG_ACPI_HOTPLUG_SLOT)			+= acpihp_slot.o
 acpihp_slot-y					= slot.o
 acpihp_slot-y					+= slot_ej0.o
 acpihp_slot-$(CONFIG_ACPI_HOTPLUG_SLOT_FAKE)	+= slot_fake.o
+
+obj-$(CONFIG_ACPI_HOTPLUG_DRIVER)		+= acpihp_drv.o
+acpihp_drv-y					= drv_main.o
diff --git a/drivers/acpi/hotplug/acpihp_drv.h b/drivers/acpi/hotplug/acpihp_drv.h
new file mode 100644
index 0000000..9b1c1c6
--- /dev/null
+++ b/drivers/acpi/hotplug/acpihp_drv.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2012 Huawei Tech. Co., Ltd.
+ * Copyright (C) 2012 Jiang Liu <jiang.liu@huawei.com>
+ * Copyright (C) 2012 Hanjun Guo <guohanjun@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
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#ifndef	__ACPIHP_DRV_H__
+#define	__ACPIHP_DRV_H__
+
+/* Commands to change state of a hotplug slot */
+enum acpihp_drv_cmd {
+	ACPIHP_DRV_CMD_NOOP = 0,
+	ACPIHP_DRV_CMD_POWERON = 0x1,
+	ACPIHP_DRV_CMD_CONNECT = 0x2,
+	ACPIHP_DRV_CMD_CONFIGURE = 0x4,
+	ACPIHP_DRV_CMD_UNCONFIGURE = 0x8,
+	ACPIHP_DRV_CMD_DISCONNECT = 0x10,
+	ACPIHP_DRV_CMD_POWEROFF = 0x20,
+	ACPIHP_DRV_CMD_CANCEL = 0x40,
+	ACPIHP_DRV_CMD_MAX
+};
+
+/* Hotplug operations may be triggered by firmware or OS */
+enum acpihp_dev_event {
+	ACPIHP_DRV_EVENT_FROM_FW,
+	ACPIHP_DRV_EVENT_FROM_OS
+};
+
+struct acpihp_slot_drv {
+	enum acpihp_dev_event	event_flag;
+	struct mutex		op_mutex; /* Prevent concurrent hotplugs. */
+	struct list_head	depend_list; /* Dependency relationship */
+	atomic_t		cancel_state;
+	atomic_t		cancel_users;
+	struct acpihp_cancel_context	cancel_ctx;
+};
+
+void acpihp_drv_get_data(struct acpihp_slot *slot,
+			 struct acpihp_slot_drv **data);
+int acpihp_drv_enumerate_devices(struct acpihp_slot *slot);
+void acpihp_drv_update_slot_state(struct acpihp_slot *slot);
+int acpihp_drv_update_slot_status(struct acpihp_slot *slot);
+
+#endif	/* __ACPIHP_DRV_H__ */
diff --git a/drivers/acpi/hotplug/drv_main.c b/drivers/acpi/hotplug/drv_main.c
new file mode 100644
index 0000000..3e2a52a
--- /dev/null
+++ b/drivers/acpi/hotplug/drv_main.c
@@ -0,0 +1,346 @@
+/*
+ * Copyright (C) 2012 Huawei Tech. Co., Ltd.
+ * Copyright (C) 2012 Jiang Liu <jiang.liu@huawei.com>
+ * Copyright (C) 2012 Hanjun Guo <guohanjun@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/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/acpi.h>
+#include <acpi/acpi_hotplug.h>
+#include "acpihp_drv.h"
+
+static struct class_interface acpihp_drv_interface;
+
+void acpihp_drv_get_data(struct acpihp_slot *slot,
+			 struct acpihp_slot_drv **data)
+{
+	*data = NULL;
+	acpihp_slot_get_drv_data(slot, &acpihp_drv_interface, (void **)data);
+}
+
+/* Update slot state according to state of devices connecting to it. */
+void acpihp_drv_update_slot_state(struct acpihp_slot *slot)
+{
+	enum acpihp_dev_type type;
+	enum acpihp_slot_state state;
+	struct klist_iter iter;
+	struct klist_node *ip;
+	struct acpihp_dev_node *dp;
+	bool connected = false;
+	bool configured = false;
+
+	if (!acpihp_slot_present(slot)) {
+		state = ACPIHP_SLOT_STATE_ABSENT;
+		goto out;
+	} else if (!acpihp_slot_powered(slot)) {
+		state = ACPIHP_SLOT_STATE_PRESENT;
+		goto out;
+	}
+
+	for (type = ACPIHP_DEV_TYPE_UNKNOWN;
+	     type < ACPIHP_DEV_TYPE_MAX && !configured;
+	     type++) {
+		klist_iter_init(&slot->dev_lists[type], &iter);
+		while ((ip = klist_next(&iter)) != NULL) {
+			connected = true;
+			dp = container_of(ip, struct acpihp_dev_node, node);
+			if (dp->state == DEVICE_STATE_CONFIGURED) {
+				configured = true;
+				break;
+			}
+		}
+		klist_iter_exit(&iter);
+	}
+
+	if (configured)
+		state = ACPIHP_SLOT_STATE_CONFIGURED;
+	else if (connected)
+		state = ACPIHP_SLOT_STATE_CONNECTED;
+	else
+		state = ACPIHP_SLOT_STATE_POWERED;
+
+out:
+	acpihp_slot_change_state(slot, state);
+}
+
+/* Update slot status according to status of devices connecting to it. */
+int acpihp_drv_update_slot_status(struct acpihp_slot *slot)
+{
+	int ret = 0;
+	enum acpihp_dev_type type;
+	struct klist_iter iter;
+	struct klist_node *ip;
+	struct acpihp_dev_node *np;
+	struct acpi_device *dev;
+	struct acpihp_dev_info *info;
+
+	if (!slot)
+		return -EINVAL;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	for (type = ACPIHP_DEV_TYPE_CONTAINER; type <= ACPIHP_DEV_TYPE_IOAPIC;
+	     type++) {
+		klist_iter_init(&slot->dev_lists[type], &iter);
+		while ((ip = klist_next(&iter)) != NULL) {
+			np = container_of(ip, struct acpihp_dev_node, node);
+			dev = container_of(np->dev, struct acpi_device, dev);
+			ret = acpihp_dev_get_info(dev, info);
+			if (ret) {
+				ACPIHP_SLOT_DEBUG(slot,
+					"fails to get info about %s.\n",
+					dev_name(&dev->dev));
+				klist_iter_exit(&iter);
+				goto out;
+			}
+
+			if (info->status & ACPIHP_DEV_STATUS_FAULT)
+				acpihp_slot_set_flag(slot,
+						ACPIHP_SLOT_FLAG_FAULT);
+			if (info->status & ACPIHP_DEV_STATUS_IRREMOVABLE)
+				acpihp_slot_set_flag(slot,
+						ACPIHP_SLOT_FLAG_IRREMOVABLE);
+		}
+		klist_iter_exit(&iter);
+	}
+
+out:
+	kfree(info);
+
+	return ret;
+}
+EXPORT_SYMBOL(acpihp_drv_update_slot_status);
+
+/* Add ACPI device to hotplug slot's device list */
+static acpi_status acpihp_drv_enum_device(struct acpi_device *dev, void *argp)
+{
+	int ret = -ENOMEM;
+	acpi_status rv = AE_ERROR;
+	enum acpihp_dev_type type;
+	enum acpihp_dev_state state;
+	struct acpihp_dev_info *info;
+	struct acpihp_slot *slot = (struct acpihp_slot *)argp;
+
+	if (acpihp_dev_get_type(dev->handle, &type)) {
+		ACPIHP_SLOT_DEBUG(slot, "fails to get device type of %s.\n",
+				  dev_name(&dev->dev));
+		return AE_ERROR;
+	} else if (type == ACPIHP_DEV_TYPE_MAX) {
+		/*
+		 * Some ACPI objects for IO devices, such as PCI/IDE etc, only
+		 * implement _ADR instead of _HID/_CID, skip them.
+		 */
+		return AE_CTRL_DEPTH;
+	}
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (info)
+		ret = acpihp_dev_get_info(dev, info);
+
+	if (!ret) {
+		if (info->status & ACPIHP_DEV_STATUS_STARTED)
+			state = DEVICE_STATE_CONFIGURED;
+		else
+			state = DEVICE_STATE_CONNECTED;
+
+		if (info->status & ACPIHP_DEV_STATUS_IRREMOVABLE)
+			acpihp_slot_set_flag(slot,
+					     ACPIHP_SLOT_FLAG_IRREMOVABLE);
+		if (info->status & ACPIHP_DEV_STATUS_FAULT)
+			acpihp_slot_set_flag(slot, ACPIHP_SLOT_FLAG_FAULT);
+
+		if (acpihp_slot_add_device(slot, type, state, &dev->dev)) {
+			ACPIHP_SLOT_DEBUG(slot, "fails to add device %s.\n",
+					  dev_name(&dev->dev));
+			acpihp_slot_set_flag(slot,
+					     ACPIHP_SLOT_FLAG_IRREMOVABLE);
+		} else
+			rv = AE_OK;
+	} else {
+		ACPIHP_SLOT_DEBUG(slot, "fails to query device info of %s.\n",
+				  dev_name(&dev->dev));
+		acpihp_slot_set_flag(slot, ACPIHP_SLOT_FLAG_IRREMOVABLE);
+	}
+
+	kfree(info);
+
+	return rv;
+}
+
+/*
+ * Enumerator all devices connecting to a slot and add them onto slot's
+ * device lists.
+ */
+int acpihp_drv_enumerate_devices(struct acpihp_slot *slot)
+{
+	return acpihp_walk_devices(slot->handle, acpihp_drv_enum_device, slot);
+}
+
+static void acpihp_drv_remove_devices(struct acpihp_slot *slot)
+{
+	enum acpihp_dev_type type;
+
+	for (type = ACPIHP_DEV_TYPE_UNKNOWN; type < ACPIHP_DEV_TYPE_MAX; type++)
+		acpihp_remove_device_list(&slot->dev_lists[type]);
+}
+
+/* Callback function for ACPI system event notification. */
+static void acpihp_drv_event_handler(acpi_handle handle, u32 event,
+				     void *context)
+{
+	/* TODO: handle ACPI hotplug events */
+}
+
+static acpi_status acpihp_drv_install_handler(struct acpihp_slot *slot)
+{
+	acpi_status status;
+
+	status = acpi_install_notify_handler(slot->handle, ACPI_SYSTEM_NOTIFY,
+					     acpihp_drv_event_handler, slot);
+	ACPIHP_SLOT_DEBUG(slot, "%s to install event handler.\n",
+			  ACPI_SUCCESS(status) ? "succeeds" : "fails");
+
+	return status;
+}
+
+static void acpihp_drv_uninstall_handler(struct acpihp_slot *slot)
+{
+	acpi_status status;
+
+	status = acpi_remove_notify_handler(slot->handle, ACPI_SYSTEM_NOTIFY,
+					    acpihp_drv_event_handler);
+	ACPIHP_SLOT_DEBUG(slot, "%s to uninstall event handler.\n",
+			  ACPI_SUCCESS(status) ? "succeeds" : "fails");
+}
+
+static int acpihp_drv_slot_add(struct device *dev, struct class_interface *intf)
+{
+	struct acpihp_slot_drv *drv_data;
+	struct acpihp_slot *slot = container_of(dev, struct acpihp_slot, dev);
+
+	/*
+	 * Try to hold a reference to the slot_ops structure to prevent
+	 * the platform specific enumerator driver from unloading.
+	 */
+	if (!slot->slot_ops || !try_module_get(slot->slot_ops->owner)) {
+		ACPIHP_SLOT_DEBUG(slot,
+				  "fails to get reference to slot_ops.\n");
+		return -EINVAL;
+	}
+
+	/* install ACPI event notification handler for slot */
+	if (ACPI_FAILURE(acpihp_drv_install_handler(slot))) {
+		ACPIHP_SLOT_DEBUG(slot, "fails to install event handler.\n");
+		module_put(slot->slot_ops->owner);
+		return -EBUSY;
+	}
+
+	/* Enumerate all devices if slot is already powered. */
+	if (!acpihp_slot_powered(slot))
+		ACPIHP_SLOT_DEBUG(slot, "is powered off.\n");
+	else if (acpihp_drv_enumerate_devices(slot))
+		acpihp_slot_set_flag(slot, ACPIHP_SLOT_FLAG_IRREMOVABLE);
+
+	acpihp_drv_update_slot_state(slot);
+
+	drv_data = kzalloc(sizeof(*drv_data), GFP_KERNEL);
+	if (drv_data) {
+		drv_data->event_flag = ACPIHP_DRV_EVENT_FROM_FW;
+		mutex_init(&drv_data->op_mutex);
+		INIT_LIST_HEAD(&drv_data->depend_list);
+	}
+	if (drv_data == NULL ||
+	    acpihp_slot_attach_drv_data(slot, intf, (void *)drv_data)) {
+		ACPIHP_SLOT_DEBUG(slot, "fails to attach driver data.\n");
+		acpihp_drv_remove_devices(slot);
+		module_put(slot->slot_ops->owner);
+		kfree(drv_data);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void acpihp_drv_intf_remove(struct device *dev,
+				  struct class_interface *intf)
+{
+	struct acpihp_slot_drv *drv_data = NULL;
+	struct acpihp_slot *slot =
+			container_of(dev, struct acpihp_slot, dev);
+
+	acpihp_drv_uninstall_handler(slot);
+	acpihp_drv_remove_devices(slot);
+	acpihp_slot_detach_drv_data(slot, intf, (void **)&drv_data);
+	if (drv_data != NULL)
+		kfree(drv_data);
+
+	module_put(slot->slot_ops->owner);
+}
+
+/*
+ * register a class driver onto the acpihp_slot_class to manage all system
+ * device hotplug slots.
+ */
+static struct class_interface acpihp_drv_interface = {
+	.class		= &acpihp_slot_class,
+	.add_dev	= acpihp_drv_slot_add,
+	.remove_dev	= acpihp_drv_intf_remove,
+};
+
+static int __init acpihp_drv_init(void)
+{
+	int retval;
+
+	retval = acpihp_register_class();
+	if (retval) {
+		ACPIHP_DEBUG("fails to register ACPI hotplug slot class.\n");
+		return retval;
+	}
+
+	retval = class_interface_register(&acpihp_drv_interface);
+	if (retval) {
+		ACPIHP_DEBUG("fails to register ACPI hotplug slot driver.\n");
+		acpihp_unregister_class();
+	}
+
+	return retval;
+}
+
+static void __exit acpihp_drv_exit(void)
+{
+	class_interface_unregister(&acpihp_drv_interface);
+	acpihp_unregister_class();
+}
+
+module_init(acpihp_drv_init);
+module_exit(acpihp_drv_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Jiang Liu <jiang.liu@huawei.com>");
+MODULE_AUTHOR("Hanjun Guo <guohanjun@huawei.com>");
-- 
1.7.9.5