- 根目录:
- drivers
- misc
- mei
- mei_dev.h
/*
*
* Intel Management Engine Interface (Intel MEI) Linux driver
* Copyright (c) 2003-2012, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
*/
#ifndef _MEI_DEV_H_
#define _MEI_DEV_H_
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/poll.h>
#include <linux/mei.h>
#include <linux/mei_cl_bus.h>
#include "hw.h"
#include "hbm.h"
/*
* watch dog definition
*/
#define MEI_WD_HDR_SIZE 4
#define MEI_WD_STOP_MSG_SIZE MEI_WD_HDR_SIZE
#define MEI_WD_START_MSG_SIZE (MEI_WD_HDR_SIZE + 16)
#define MEI_WD_DEFAULT_TIMEOUT 120 /* seconds */
#define MEI_WD_MIN_TIMEOUT 120 /* seconds */
#define MEI_WD_MAX_TIMEOUT 65535 /* seconds */
#define MEI_WD_STOP_TIMEOUT 10 /* msecs */
#define MEI_WD_STATE_INDEPENDENCE_MSG_SENT (1 << 0)
#define MEI_RD_MSG_BUF_SIZE (128 * sizeof(u32))
/*
* AMTHI Client UUID
*/
extern const uuid_le mei_amthif_guid;
/*
* Watchdog Client UUID
*/
extern const uuid_le mei_wd_guid;
/*
* Number of Maximum MEI Clients
*/
#define MEI_CLIENTS_MAX 256
/*
* maximum number of consecutive resets
*/
#define MEI_MAX_CONSEC_RESET 3
/*
* Number of File descriptors/handles
* that can be opened to the driver.
*
* Limit to 255: 256 Total Clients
* minus internal client for MEI Bus Messages
*/
#define MEI_MAX_OPEN_HANDLE_COUNT (MEI_CLIENTS_MAX - 1)
/*
* Internal Clients Number
*/
#define MEI_HOST_CLIENT_ID_ANY (-1)
#define MEI_HBM_HOST_CLIENT_ID 0 /* not used, just for documentation */
#define MEI_WD_HOST_CLIENT_ID 1
#define MEI_IAMTHIF_HOST_CLIENT_ID 2
/* File state */
enum file_state {
MEI_FILE_INITIALIZING = 0,
MEI_FILE_CONNECTING,
MEI_FILE_CONNECTED,
MEI_FILE_DISCONNECTING,
MEI_FILE_DISCONNECTED
};
/* MEI device states */
enum mei_dev_state {
MEI_DEV_INITIALIZING = 0,
MEI_DEV_INIT_CLIENTS,
MEI_DEV_ENABLED,
MEI_DEV_RESETTING,
MEI_DEV_DISABLED,
MEI_DEV_POWER_DOWN,
MEI_DEV_POWER_UP
};
const char *mei_dev_state_str(int state);
enum iamthif_states {
MEI_IAMTHIF_IDLE,
MEI_IAMTHIF_WRITING,
MEI_IAMTHIF_FLOW_CONTROL,
MEI_IAMTHIF_READING,
MEI_IAMTHIF_READ_COMPLETE
};
enum mei_file_transaction_states {
MEI_IDLE,
MEI_WRITING,
MEI_WRITE_COMPLETE,
MEI_FLOW_CONTROL,
MEI_READING,
MEI_READ_COMPLETE
};
enum mei_wd_states {
MEI_WD_IDLE,
MEI_WD_RUNNING,
MEI_WD_STOPPING,
};
/**
* enum mei_cb_file_ops - file operation associated with the callback
* @MEI_FOP_READ: read
* @MEI_FOP_WRITE: write
* @MEI_FOP_CONNECT: connect
* @MEI_FOP_DISCONNECT: disconnect
* @MEI_FOP_DISCONNECT_RSP: disconnect response
*/
enum mei_cb_file_ops {
MEI_FOP_READ = 0,
MEI_FOP_WRITE,
MEI_FOP_CONNECT,
MEI_FOP_DISCONNECT,
MEI_FOP_DISCONNECT_RSP,
};
/*
* Intel MEI message data struct
*/
struct mei_msg_data {
u32 size;
unsigned char *data;
};
/* Maximum number of processed FW status registers */
#define MEI_FW_STATUS_MAX 6
/* Minimal buffer for FW status string (8 bytes in dw + space or '\0') */
#define MEI_FW_STATUS_STR_SZ (MEI_FW_STATUS_MAX * (8 + 1))
/*
* struct mei_fw_status - storage of FW status data
*
* @count: number of actually available elements in array
* @status: FW status registers
*/
struct mei_fw_status {
int count;
u32 status[MEI_FW_STATUS_MAX];
};
/**
* struct mei_me_client - representation of me (fw) client
*
* @list: link in me client list
* @refcnt: struct reference count
* @props: client properties
* @client_id: me client id
* @mei_flow_ctrl_creds: flow control credits
*/
struct mei_me_client {
struct list_head list;
struct kref refcnt;
struct mei_client_properties props;
u8 client_id;
u8 mei_flow_ctrl_creds;
};
struct mei_cl;
/**
* struct mei_cl_cb - file operation callback structure
*
* @list: link in callback queue
* @cl: file client who is running this operation
* @fop_type: file operation type
* @buf: buffer for data associated with the callback
* @buf_idx: last read index
* @read_time: last read operation time stamp (iamthif)
* @file_object: pointer to file structure
* @status: io status of the cb
* @internal: communication between driver and FW flag
* @completed: the transfer or reception has completed
*/
struct mei_cl_cb {
struct list_head list;
struct mei_cl *cl;
enum mei_cb_file_ops fop_type;
struct mei_msg_data buf;
unsigned long buf_idx;
unsigned long read_time;
struct file *file_object;
int status;
u32 internal:1;
u32 completed:1;
};
/**
* struct mei_cl - me client host representation
* carried in file->private_data
*
* @link: link in the clients list
* @dev: mei parent device
* @state: file operation state
* @tx_wait: wait queue for tx completion
* @rx_wait: wait queue for rx completion
* @wait: wait queue for management operation
* @status: connection status
* @cl_uuid: client uuid name
* @host_client_id: host id
* @me_client_id: me/fw id
* @mei_flow_ctrl_creds: transmit flow credentials
* @timer_count: watchdog timer for operation completion
* @writing_state: state of the tx
* @rd_pending: pending read credits
* @rd_completed: completed read
*
* @device: device on the mei client bus
* @device_link: link to bus clients
*/
struct mei_cl {
struct list_head link;
struct mei_device *dev;
enum file_state state;
wait_queue_head_t tx_wait;
wait_queue_head_t rx_wait;
wait_queue_head_t wait;
int status;
uuid_le cl_uuid;
u8 host_client_id;
u8 me_client_id;
u8 mei_flow_ctrl_creds;
u8 timer_count;
enum mei_file_transaction_states writing_state;
struct list_head rd_pending;
struct list_head rd_completed;
/* MEI CL bus data */
struct mei_cl_device *device;
struct list_head device_link;
};
/** struct mei_hw_ops
*
* @host_is_ready : query for host readiness
* @hw_is_ready : query if hw is ready
* @hw_reset : reset hw
* @hw_start : start hw after reset
* @hw_config : configure hw
* @fw_status : get fw status registers
* @pg_state : power gating state of the device
* @pg_is_enabled : is power gating enabled
* @intr_clear : clear pending interrupts
* @intr_enable : enable interrupts
* @intr_disable : disable interrupts
* @hbuf_free_slots : query for write buffer empty slots
* @hbuf_is_ready : query if write buffer is empty
* @hbuf_max_len : query for write buffer max len
* @write : write a message to FW
* @rdbuf_full_slots : query how many slots are filled
* @read_hdr : get first 4 bytes (header)
* @read : read a buffer from the FW
*/
struct mei_hw_ops {
bool (*host_is_ready)(struct mei_device *dev);
bool (*hw_is_ready)(struct mei_device *dev);
int (*hw_reset)(struct mei_device *dev, bool enable);
int (*hw_start)(struct mei_device *dev);
void (*hw_config)(struct mei_device *dev);
int (*fw_status)(struct mei_device *dev, struct mei_fw_status *fw_sts);
enum mei_pg_state (*pg_state)(struct mei_device *dev);
bool (*pg_is_enabled)(struct mei_device *dev);
void (*intr_clear)(struct mei_device *dev);
void (*intr_enable)(struct mei_device *dev);
void (*intr_disable)(struct mei_device *dev);
int (*hbuf_free_slots)(struct mei_device *dev);
bool (*hbuf_is_ready)(struct mei_device *dev);
size_t (*hbuf_max_len)(const struct mei_device *dev);
int (*write)(struct mei_device *dev,
struct mei_msg_hdr *hdr,
unsigned char *buf);
int (*rdbuf_full_slots)(struct mei_device *dev);
u32 (*read_hdr)(const struct mei_device *dev);
int (*read)(struct mei_device *dev,
unsigned char *buf, unsigned long len);
};
/* MEI bus API*/
/**
* struct mei_cl_ops - MEI CL device ops
* This structure allows ME host clients to implement technology
* specific operations.
*
* @enable: Enable an MEI CL device. Some devices require specific
* HECI commands to initialize completely.
* @disable: Disable an MEI CL device.
* @send: Tx hook for the device. This allows ME host clients to trap
* the device driver buffers before actually physically
* pushing it to the ME.
* @recv: Rx hook for the device. This allows ME host clients to trap the
* ME buffers before forwarding them to the device driver.
*/
struct mei_cl_ops {
int (*enable)(struct mei_cl_device *device);
int (*disable)(struct mei_cl_device *device);
int (*send)(struct mei_cl_device *device, u8 *buf, size_t length);
int (*recv)(struct mei_cl_device *device, u8 *buf, size_t length);
};
struct mei_cl_device *mei_cl_add_device(struct mei_device *dev,
uuid_le uuid, char *name,
struct mei_cl_ops *ops);
void mei_cl_remove_device(struct mei_cl_device *device);
ssize_t __mei_cl_async_send(struct mei_cl *cl, u8 *buf, size_t length);
ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length);
ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length);
void mei_cl_bus_rx_event(struct mei_cl *cl);
void mei_cl_bus_remove_devices(struct mei_device *dev);
int mei_cl_bus_init(void);
void mei_cl_bus_exit(void);
struct mei_cl *mei_cl_bus_find_cl_by_uuid(struct mei_device *dev, uuid_le uuid);
/**
* struct mei_cl_device - MEI device handle
* An mei_cl_device pointer is returned from mei_add_device()
* and links MEI bus clients to their actual ME host client pointer.
* Drivers for MEI devices will get an mei_cl_device pointer
* when being probed and shall use it for doing ME bus I/O.
*
* @dev: linux driver model device pointer
* @cl: mei client
* @ops: ME transport ops
* @event_work: async work to execute event callback
* @event_cb: Drivers register this callback to get asynchronous ME
* events (e.g. Rx buffer pending) notifications.
* @event_context: event callback run context
* @events: Events bitmask sent to the driver.
* @priv_data: client private data
*/
struct mei_cl_device {
struct device dev;
struct mei_cl *cl;
const struct mei_cl_ops *ops;
struct work_struct event_work;
mei_cl_event_cb_t event_cb;
void *event_context;
unsigned long events;
void *priv_data;
};
/**
* enum mei_pg_event - power gating transition events
*
* @MEI_PG_EVENT_IDLE: the driver is not in power gating transition
* @MEI_PG_EVENT_WAIT: the driver is waiting for a pg event to complete
* @MEI_PG_EVENT_RECEIVED: the driver received pg event
*/
enum mei_pg_event {
MEI_PG_EVENT_IDLE,
MEI_PG_EVENT_WAIT,
MEI_PG_EVENT_RECEIVED,
};
/**
* enum mei_pg_state - device internal power gating state
*
* @MEI_PG_OFF: device is not power gated - it is active
* @MEI_PG_ON: device is power gated - it is in lower power state
*/
enum mei_pg_state {
MEI_PG_OFF = 0,
MEI_PG_ON = 1,
};
const char *mei_pg_state_str(enum mei_pg_state state);
/**
* struct mei_device - MEI private device struct
*
* @dev : device on a bus
* @cdev : character device
* @minor : minor number allocated for device
*
* @write_list : write pending list
* @write_waiting_list : write completion list
* @ctrl_wr_list : pending control write list
* @ctrl_rd_list : pending control read list
*
* @file_list : list of opened handles
* @open_handle_count: number of opened handles
*
* @device_lock : big device lock
* @timer_work : MEI timer delayed work (timeouts)
*
* @recvd_hw_ready : hw ready message received flag
*
* @wait_hw_ready : wait queue for receive HW ready message form FW
* @wait_pg : wait queue for receive PG message from FW
* @wait_hbm_start : wait queue for receive HBM start message from FW
* @wait_stop_wd : wait queue for receive WD stop message from FW
*
* @reset_count : number of consecutive resets
* @dev_state : device state
* @hbm_state : state of host bus message protocol
* @init_clients_timer : HBM init handshake timeout
*
* @pg_event : power gating event
* @pg_domain : runtime PM domain
*
* @rd_msg_buf : control messages buffer
* @rd_msg_hdr : read message header storage
*
* @hbuf_depth : depth of hardware host/write buffer is slots
* @hbuf_is_ready : query if the host host/write buffer is ready
* @wr_msg : the buffer for hbm control messages
*
* @version : HBM protocol version in use
* @hbm_f_pg_supported : hbm feature pgi protocol
*
* @me_clients_rwsem: rw lock over me_clients list
* @me_clients : list of FW clients
* @me_clients_map : FW clients bit map
* @host_clients_map : host clients id pool
* @me_client_index : last FW client index in enumeration
*
* @wd_cl : watchdog client
* @wd_state : watchdog client state
* @wd_pending : watchdog command is pending
* @wd_timeout : watchdog expiration timeout
* @wd_data : watchdog message buffer
*
* @amthif_cmd_list : amthif list for cmd waiting
* @amthif_rd_complete_list : amthif list for reading completed cmd data
* @iamthif_file_object : file for current amthif operation
* @iamthif_cl : amthif host client
* @iamthif_current_cb : amthif current operation callback
* @iamthif_open_count : number of opened amthif connections
* @iamthif_mtu : amthif client max message length
* @iamthif_timer : time stamp of current amthif command completion
* @iamthif_stall_timer : timer to detect amthif hang
* @iamthif_state : amthif processor state
* @iamthif_canceled : current amthif command is canceled
*
* @init_work : work item for the device init
* @reset_work : work item for the device reset
*
* @device_list : mei client bus list
*
* @dbgfs_dir : debugfs mei root directory
*
* @ops: : hw specific operations
* @hw : hw specific data
*/
struct mei_device {
struct device *dev;
struct cdev cdev;
int minor;
struct mei_cl_cb write_list;
struct mei_cl_cb write_waiting_list;
struct mei_cl_cb ctrl_wr_list;
struct mei_cl_cb ctrl_rd_list;
struct list_head file_list;
long open_handle_count;
struct mutex device_lock;
struct delayed_work timer_work;
bool recvd_hw_ready;
/*
* waiting queue for receive message from FW
*/
wait_queue_head_t wait_hw_ready;
wait_queue_head_t wait_pg;
wait_queue_head_t wait_hbm_start;
wait_queue_head_t wait_stop_wd;
/*
* mei device states
*/
unsigned long reset_count;
enum mei_dev_state dev_state;
enum mei_hbm_state hbm_state;
u16 init_clients_timer;
/*
* Power Gating support
*/
enum mei_pg_event pg_event;
#ifdef CONFIG_PM
struct dev_pm_domain pg_domain;
#endif /* CONFIG_PM */
unsigned char rd_msg_buf[MEI_RD_MSG_BUF_SIZE];
u32 rd_msg_hdr;
/* write buffer */
u8 hbuf_depth;
bool hbuf_is_ready;
/* used for control messages */
struct {
struct mei_msg_hdr hdr;
unsigned char data[128];
} wr_msg;
struct hbm_version version;
unsigned int hbm_f_pg_supported:1;
struct rw_semaphore me_clients_rwsem;
struct list_head me_clients;
DECLARE_BITMAP(me_clients_map, MEI_CLIENTS_MAX);
DECLARE_BITMAP(host_clients_map, MEI_CLIENTS_MAX);
unsigned long me_client_index;
struct mei_cl wd_cl;
enum mei_wd_states wd_state;
bool wd_pending;
u16 wd_timeout;
unsigned char wd_data[MEI_WD_START_MSG_SIZE];
/* amthif list for cmd waiting */
struct mei_cl_cb amthif_cmd_list;
/* driver managed amthif list for reading completed amthif cmd data */
struct mei_cl_cb amthif_rd_complete_list;
struct file *iamthif_file_object;
struct mei_cl iamthif_cl;
struct mei_cl_cb *iamthif_current_cb;
long iamthif_open_count;
int iamthif_mtu;
unsigned long iamthif_timer;
u32 iamthif_stall_timer;
enum iamthif_states iamthif_state;
bool iamthif_canceled;
struct work_struct init_work;
struct work_struct reset_work;
/* List of bus devices */
struct list_head device_list;
#if IS_ENABLED(CONFIG_DEBUG_FS)
struct dentry *dbgfs_dir;
#endif /* CONFIG_DEBUG_FS */
const struct mei_hw_ops *ops;
char hw[0] __aligned(sizeof(void *));
};
static inline unsigned long mei_secs_to_jiffies(unsigned long sec)
{
return msecs_to_jiffies(sec * MSEC_PER_SEC);
}
/**
* mei_data2slots - get slots - number of (dwords) from a message length
* + size of the mei header
*
* @length: size of the messages in bytes
*
* Return: number of slots
*/
static inline u32 mei_data2slots(size_t length)
{
return DIV_ROUND_UP(sizeof(struct mei_msg_hdr) + length, 4);
}
/**
* mei_slots2data - get data in slots - bytes from slots
*
* @slots: number of available slots
*
* Return: number of bytes in slots
*/
static inline u32 mei_slots2data(int slots)
{
return slots * 4;
}
/*
* mei init function prototypes
*/
void mei_device_init(struct mei_device *dev,
struct device *device,
const struct mei_hw_ops *hw_ops);
int mei_reset(struct mei_device *dev);
int mei_start(struct mei_device *dev);
int mei_restart(struct mei_device *dev);
void mei_stop(struct mei_device *dev);
void mei_cancel_work(struct mei_device *dev);
/*
* MEI interrupt functions prototype
*/
void mei_timer(struct work_struct *work);
int mei_irq_read_handler(struct mei_device *dev,
struct mei_cl_cb *cmpl_list, s32 *slots);
int mei_irq_write_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list);
void mei_irq_compl_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list);
/*
* AMTHIF - AMT Host Interface Functions
*/
void mei_amthif_reset_params(struct mei_device *dev);
int mei_amthif_host_init(struct mei_device *dev);
int mei_amthif_read(struct mei_device *dev, struct file *file,
char __user *ubuf, size_t length, loff_t *offset);
unsigned int mei_amthif_poll(struct mei_device *dev,
struct file *file, poll_table *wait);
int mei_amthif_release(struct mei_device *dev, struct file *file);
struct mei_cl_cb *mei_amthif_find_read_list_entry(struct mei_device *dev,
struct file *file);
int mei_amthif_write(struct mei_cl *cl, struct mei_cl_cb *cb);
int mei_amthif_run_next_cmd(struct mei_device *dev);
int mei_amthif_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
struct mei_cl_cb *cmpl_list);
void mei_amthif_complete(struct mei_device *dev, struct mei_cl_cb *cb);
int mei_amthif_irq_read_msg(struct mei_cl *cl,
struct mei_msg_hdr *mei_hdr,
struct mei_cl_cb *complete_list);
int mei_amthif_irq_read(struct mei_device *dev, s32 *slots);
/*
* NFC functions
*/
int mei_nfc_host_init(struct mei_device *dev);
void mei_nfc_host_exit(struct mei_device *dev);
/*
* NFC Client UUID
*/
extern const uuid_le mei_nfc_guid;
int mei_wd_send(struct mei_device *dev);
int mei_wd_stop(struct mei_device *dev);
int mei_wd_host_init(struct mei_device *dev);
/*
* mei_watchdog_register - Registering watchdog interface
* once we got connection to the WD Client
* @dev: mei device
*/
int mei_watchdog_register(struct mei_device *dev);
/*
* mei_watchdog_unregister - Unregistering watchdog interface
* @dev: mei device
*/
void mei_watchdog_unregister(struct mei_device *dev);
/*
* Register Access Function
*/
static inline void mei_hw_config(struct mei_device *dev)
{
dev->ops->hw_config(dev);
}
static inline enum mei_pg_state mei_pg_state(struct mei_device *dev)
{
return dev->ops->pg_state(dev);
}
static inline bool mei_pg_is_enabled(struct mei_device *dev)
{
return dev->ops->pg_is_enabled(dev);
}
static inline int mei_hw_reset(struct mei_device *dev, bool enable)
{
return dev->ops->hw_reset(dev, enable);
}
static inline int mei_hw_start(struct mei_device *dev)
{
return dev->ops->hw_start(dev);
}
static inline void mei_clear_interrupts(struct mei_device *dev)
{
dev->ops->intr_clear(dev);
}
static inline void mei_enable_interrupts(struct mei_device *dev)
{
dev->ops->intr_enable(dev);
}
static inline void mei_disable_interrupts(struct mei_device *dev)
{
dev->ops->intr_disable(dev);
}
static inline bool mei_host_is_ready(struct mei_device *dev)
{
return dev->ops->host_is_ready(dev);
}
static inline bool mei_hw_is_ready(struct mei_device *dev)
{
return dev->ops->hw_is_ready(dev);
}
static inline bool mei_hbuf_is_ready(struct mei_device *dev)
{
return dev->ops->hbuf_is_ready(dev);
}
static inline int mei_hbuf_empty_slots(struct mei_device *dev)
{
return dev->ops->hbuf_free_slots(dev);
}
static inline size_t mei_hbuf_max_len(const struct mei_device *dev)
{
return dev->ops->hbuf_max_len(dev);
}
static inline int mei_write_message(struct mei_device *dev,
struct mei_msg_hdr *hdr,
unsigned char *buf)
{
return dev->ops->write(dev, hdr, buf);
}
static inline u32 mei_read_hdr(const struct mei_device *dev)
{
return dev->ops->read_hdr(dev);
}
static inline void mei_read_slots(struct mei_device *dev,
unsigned char *buf, unsigned long len)
{
dev->ops->read(dev, buf, len);
}
static inline int mei_count_full_read_slots(struct mei_device *dev)
{
return dev->ops->rdbuf_full_slots(dev);
}
static inline int mei_fw_status(struct mei_device *dev,
struct mei_fw_status *fw_status)
{
return dev->ops->fw_status(dev, fw_status);
}
bool mei_hbuf_acquire(struct mei_device *dev);
bool mei_write_is_idle(struct mei_device *dev);
#if IS_ENABLED(CONFIG_DEBUG_FS)
int mei_dbgfs_register(struct mei_device *dev, const char *name);
void mei_dbgfs_deregister(struct mei_device *dev);
#else
static inline int mei_dbgfs_register(struct mei_device *dev, const char *name)
{
return 0;
}
static inline void mei_dbgfs_deregister(struct mei_device *dev) {}
#endif /* CONFIG_DEBUG_FS */
int mei_register(struct mei_device *dev, struct device *parent);
void mei_deregister(struct mei_device *dev);
#define MEI_HDR_FMT "hdr:host=%02d me=%02d len=%d internal=%1d comp=%1d"
#define MEI_HDR_PRM(hdr) \
(hdr)->host_addr, (hdr)->me_addr, \
(hdr)->length, (hdr)->internal, (hdr)->msg_complete
ssize_t mei_fw_status2str(struct mei_fw_status *fw_sts, char *buf, size_t len);
/**
* mei_fw_status_str - fetch and convert fw status registers to printable string
*
* @dev: the device structure
* @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ
* @len: buffer len must be >= MEI_FW_STATUS_STR_SZ
*
* Return: number of bytes written or < 0 on failure
*/
static inline ssize_t mei_fw_status_str(struct mei_device *dev,
char *buf, size_t len)
{
struct mei_fw_status fw_status;
int ret;
buf[0] = '\0';
ret = mei_fw_status(dev, &fw_status);
if (ret)
return ret;
ret = mei_fw_status2str(&fw_status, buf, MEI_FW_STATUS_STR_SZ);
return ret;
}
#endif