path: root/drivers/acpi/acpi_ipmi.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  acpi_ipmi.c - ACPI IPMI opregion
 *
 *  Copyright (C) 2010, 2013 Intel Corporation
 *    Author: Zhao Yakui <yakui.zhao@intel.com>
 *            Lv Zheng <lv.zheng@intel.com>
 */

#include <linux/module.h>
#include <linux/acpi.h>
#include <linux/ipmi.h>
#include <linux/spinlock.h>

MODULE_AUTHOR("Zhao Yakui");
MODULE_DESCRIPTION("ACPI IPMI Opregion driver");
MODULE_LICENSE("GPL");

#define ACPI_IPMI_OK			0
#define ACPI_IPMI_TIMEOUT		0x10
#define ACPI_IPMI_UNKNOWN		0x07
/* the IPMI timeout is 5s */
#define IPMI_TIMEOUT			(5000)
#define ACPI_IPMI_MAX_MSG_LENGTH	64

struct acpi_ipmi_device {
	/* the device list attached to driver_data.ipmi_devices */
	struct list_head head;

	/* the IPMI request message list */
	struct list_head tx_msg_list;

	spinlock_t tx_msg_lock;
	acpi_handle handle;
	struct device *dev;
	struct ipmi_user *user_interface;
	int ipmi_ifnum; /* IPMI interface number */
	long curr_msgid;
	bool dead;
	struct kref kref;
};

struct ipmi_driver_data {
	struct list_head ipmi_devices;
	struct ipmi_smi_watcher bmc_events;
	const struct ipmi_user_hndl ipmi_hndlrs;
	struct mutex ipmi_lock;

	/*
	 * NOTE: IPMI System Interface Selection
	 * There is no system interface specified by the IPMI operation
	 * region access.  We try to select one system interface with ACPI
	 * handle set.  IPMI messages passed from the ACPI codes are sent
	 * to this selected global IPMI system interface.
	 */
	struct acpi_ipmi_device *selected_smi;
};

struct acpi_ipmi_msg {
	struct list_head head;

	/*
	 * General speaking the addr type should be SI_ADDR_TYPE. And
	 * the addr channel should be BMC.
	 * In fact it can also be IPMB type. But we will have to
	 * parse it from the Netfn command buffer. It is so complex
	 * that it is skipped.
	 */
	struct ipmi_addr addr;
	long tx_msgid;

	/* it is used to track whether the IPMI message is finished */
	struct completion tx_complete;

	struct kernel_ipmi_msg tx_message;
	int msg_done;

	/* tx/rx data . And copy it from/to ACPI object buffer */
	u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
	u8 rx_len;

	struct acpi_ipmi_device *device;
	struct kref kref;
};

/* IPMI request/response buffer per ACPI 4.0, sec 5.5.2.4.3.2 */
struct acpi_ipmi_buffer {
	u8 status;
	u8 length;
	u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
};

static void ipmi_register_bmc(int iface, struct device *dev);
static void ipmi_bmc_gone(int iface);
static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);

static struct ipmi_driver_data driver_data = {
	.ipmi_devices = LIST_HEAD_INIT(driver_data.ipmi_devices),
	.bmc_events = {
		.owner = THIS_MODULE,
		.new_smi = ipmi_register_bmc,
		.smi_gone = ipmi_bmc_gone,
	},
	.ipmi_hndlrs = {
		.ipmi_recv_hndl = ipmi_msg_handler,
	},
	.ipmi_lock = __MUTEX_INITIALIZER(driver_data.ipmi_lock)
};

static struct acpi_ipmi_device *
ipmi_dev_alloc(int iface, struct device *dev, acpi_handle handle)
{
	struct acpi_ipmi_device *ipmi_device;
	int err;
	struct ipmi_user *user;

	ipmi_device = kzalloc(sizeof(*ipmi_device), GFP_KERNEL);
	if (!ipmi_device)
		return NULL;

	kref_init(&ipmi_device->kref);
	INIT_LIST_HEAD(&ipmi_device->head);
	INIT_LIST_HEAD(&ipmi_device->tx_msg_list);
	spin_lock_init(&ipmi_device->tx_msg_lock);
	ipmi_device->handle = handle;
	ipmi_device->dev = get_device(dev);
	ipmi_device->ipmi_ifnum = iface;

	err = ipmi_create_user(iface, &driver_data.ipmi_hndlrs,
			       ipmi_device, &user);
	if (err) {
		put_device(dev);
		kfree(ipmi_device);
		return NULL;
	}
	ipmi_device->user_interface = user;

	return ipmi_device;
}

static void ipmi_dev_release(struct acpi_ipmi_device *ipmi_device)
{
	ipmi_destroy_user(ipmi_device->user_interface);
	put_device(ipmi_device->dev);
	kfree(ipmi_device);
}

static void ipmi_dev_release_kref(struct kref *kref)
{
	struct acpi_ipmi_device *ipmi =
		container_of(kref, struct acpi_ipmi_device, kref);

	ipmi_dev_release(ipmi);
}

static void __ipmi_dev_kill(struct acpi_ipmi_device *ipmi_device)
{
	list_del(&ipmi_device->head);
	if (driver_data.selected_smi == ipmi_device)
		driver_data.selected_smi = NULL;

	/*
	 * Always setting dead flag after deleting from the list or
	 * list_for_each_entry() codes must get changed.
	 */
	ipmi_device->dead = true;
}

static struct acpi_ipmi_device *acpi_ipmi_dev_get(void)
{
	struct acpi_ipmi_device *ipmi_device = NULL;

	mutex_lock(&driver_data.ipmi_lock);
	if (driver_data.selected_smi) {
		ipmi_device = driver_data.selected_smi;
		kref_get(&ipmi_device->kref);
	}
	mutex_unlock(&driver_data.ipmi_lock);

	return ipmi_device;
}

static void acpi_ipmi_dev_put(struct acpi_ipmi_device *ipmi_device)
{
	kref_put(&ipmi_device->kref, ipmi_dev_release_kref);
}

static struct acpi_ipmi_msg *ipmi_msg_alloc(void)
{
	struct acpi_ipmi_device *ipmi;
	struct acpi_ipmi_msg *ipmi_msg;

	ipmi = acpi_ipmi_dev_get();
	if (!ipmi)
		return NULL;

	ipmi_msg = kzalloc(sizeof(struct acpi_ipmi_msg), GFP_KERNEL);
	if (!ipmi_msg) {
		acpi_ipmi_dev_put(ipmi);
		return NULL;
	}

	kref_init(&ipmi_msg->kref);
	init_completion(&ipmi_msg->tx_complete);
	INIT_LIST_HEAD(&ipmi_msg->head);
	ipmi_msg->device = ipmi;
	ipmi_msg->msg_done = ACPI_IPMI_UNKNOWN;

	return ipmi_msg;
}

static void ipmi_msg_release(struct acpi_ipmi_msg *tx_msg)
{
	acpi_ipmi_dev_put(tx_msg->device);
	kfree(tx_msg);
}

static void ipmi_msg_release_kref(struct kref *kref)
{
	struct acpi_ipmi_msg *tx_msg =
		container_of(kref, struct acpi_ipmi_msg, kref);

	ipmi_msg_release(tx_msg);
}

static struct acpi_ipmi_msg *acpi_ipmi_msg_get(struct acpi_ipmi_msg *tx_msg)
{
	kref_get(&tx_msg->kref);

	return tx_msg;
}

static void acpi_ipmi_msg_put(struct acpi_ipmi_msg *tx_msg)
{
	kref_put(&tx_msg->kref, ipmi_msg_release_kref);
}

#define IPMI_OP_RGN_NETFN(offset)	((offset >> 8) & 0xff)
#define IPMI_OP_RGN_CMD(offset)		(offset & 0xff)
static int acpi_format_ipmi_request(struct acpi_ipmi_msg *tx_msg,
				    acpi_physical_address address,
				    acpi_integer *value)
{
	struct kernel_ipmi_msg *msg;
	struct acpi_ipmi_buffer *buffer;
	struct acpi_ipmi_device *device;
	unsigned long flags;

	msg = &tx_msg->tx_message;

	/*
	 * IPMI network function and command are encoded in the address
	 * within the IPMI OpRegion; see ACPI 4.0, sec 5.5.2.4.3.
	 */
	msg->netfn = IPMI_OP_RGN_NETFN(address);
	msg->cmd = IPMI_OP_RGN_CMD(address);
	msg->data = tx_msg->data;

	/*
	 * value is the parameter passed by the IPMI opregion space handler.
	 * It points to the IPMI request message buffer
	 */
	buffer = (struct acpi_ipmi_buffer *)value;

	/* copy the tx message data */
	if (buffer->