1 /* 2 * 3 * Intel Management Engine Interface (Intel MEI) Linux driver 4 * Copyright (c) 2003-2018, Intel Corporation. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms and conditions of the GNU General Public License, 8 * version 2, as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 13 * more details. 14 * 15 */ 16 17 #ifndef _MEI_DEV_H_ 18 #define _MEI_DEV_H_ 19 20 #include <linux/types.h> 21 #include <linux/cdev.h> 22 #include <linux/poll.h> 23 #include <linux/mei.h> 24 #include <linux/mei_cl_bus.h> 25 26 #include "hw.h" 27 #include "hbm.h" 28 29 #define MEI_RD_MSG_BUF_SIZE (128 * sizeof(u32)) 30 31 /* 32 * Number of Maximum MEI Clients 33 */ 34 #define MEI_CLIENTS_MAX 256 35 36 /* 37 * maximum number of consecutive resets 38 */ 39 #define MEI_MAX_CONSEC_RESET 3 40 41 /* 42 * Number of File descriptors/handles 43 * that can be opened to the driver. 44 * 45 * Limit to 255: 256 Total Clients 46 * minus internal client for MEI Bus Messages 47 */ 48 #define MEI_MAX_OPEN_HANDLE_COUNT (MEI_CLIENTS_MAX - 1) 49 50 /* File state */ 51 enum file_state { 52 MEI_FILE_UNINITIALIZED = 0, 53 MEI_FILE_INITIALIZING, 54 MEI_FILE_CONNECTING, 55 MEI_FILE_CONNECTED, 56 MEI_FILE_DISCONNECTING, 57 MEI_FILE_DISCONNECT_REPLY, 58 MEI_FILE_DISCONNECT_REQUIRED, 59 MEI_FILE_DISCONNECTED, 60 }; 61 62 /* MEI device states */ 63 enum mei_dev_state { 64 MEI_DEV_INITIALIZING = 0, 65 MEI_DEV_INIT_CLIENTS, 66 MEI_DEV_ENABLED, 67 MEI_DEV_RESETTING, 68 MEI_DEV_DISABLED, 69 MEI_DEV_POWER_DOWN, 70 MEI_DEV_POWER_UP 71 }; 72 73 const char *mei_dev_state_str(int state); 74 75 enum mei_file_transaction_states { 76 MEI_IDLE, 77 MEI_WRITING, 78 MEI_WRITE_COMPLETE, 79 }; 80 81 /** 82 * enum mei_cb_file_ops - file operation associated with the callback 83 * @MEI_FOP_READ: read 84 * @MEI_FOP_WRITE: write 85 * @MEI_FOP_CONNECT: connect 86 * @MEI_FOP_DISCONNECT: disconnect 87 * @MEI_FOP_DISCONNECT_RSP: disconnect response 88 * @MEI_FOP_NOTIFY_START: start notification 89 * @MEI_FOP_NOTIFY_STOP: stop notification 90 */ 91 enum mei_cb_file_ops { 92 MEI_FOP_READ = 0, 93 MEI_FOP_WRITE, 94 MEI_FOP_CONNECT, 95 MEI_FOP_DISCONNECT, 96 MEI_FOP_DISCONNECT_RSP, 97 MEI_FOP_NOTIFY_START, 98 MEI_FOP_NOTIFY_STOP, 99 }; 100 101 /** 102 * enum mei_cl_io_mode - io mode between driver and fw 103 * 104 * @MEI_CL_IO_TX_BLOCKING: send is blocking 105 * @MEI_CL_IO_TX_INTERNAL: internal communication between driver and FW 106 * 107 * @MEI_CL_IO_RX_NONBLOCK: recv is non-blocking 108 */ 109 enum mei_cl_io_mode { 110 MEI_CL_IO_TX_BLOCKING = BIT(0), 111 MEI_CL_IO_TX_INTERNAL = BIT(1), 112 113 MEI_CL_IO_RX_NONBLOCK = BIT(2), 114 }; 115 116 /* 117 * Intel MEI message data struct 118 */ 119 struct mei_msg_data { 120 size_t size; 121 unsigned char *data; 122 }; 123 124 /* Maximum number of processed FW status registers */ 125 #define MEI_FW_STATUS_MAX 6 126 /* Minimal buffer for FW status string (8 bytes in dw + space or '\0') */ 127 #define MEI_FW_STATUS_STR_SZ (MEI_FW_STATUS_MAX * (8 + 1)) 128 129 130 /* 131 * struct mei_fw_status - storage of FW status data 132 * 133 * @count: number of actually available elements in array 134 * @status: FW status registers 135 */ 136 struct mei_fw_status { 137 int count; 138 u32 status[MEI_FW_STATUS_MAX]; 139 }; 140 141 /** 142 * struct mei_me_client - representation of me (fw) client 143 * 144 * @list: link in me client list 145 * @refcnt: struct reference count 146 * @props: client properties 147 * @client_id: me client id 148 * @tx_flow_ctrl_creds: flow control credits 149 * @connect_count: number connections to this client 150 * @bus_added: added to bus 151 */ 152 struct mei_me_client { 153 struct list_head list; 154 struct kref refcnt; 155 struct mei_client_properties props; 156 u8 client_id; 157 u8 tx_flow_ctrl_creds; 158 u8 connect_count; 159 u8 bus_added; 160 }; 161 162 163 struct mei_cl; 164 165 /** 166 * struct mei_cl_cb - file operation callback structure 167 * 168 * @list: link in callback queue 169 * @cl: file client who is running this operation 170 * @fop_type: file operation type 171 * @buf: buffer for data associated with the callback 172 * @buf_idx: last read index 173 * @fp: pointer to file structure 174 * @status: io status of the cb 175 * @internal: communication between driver and FW flag 176 * @blocking: transmission blocking mode 177 * @completed: the transfer or reception has completed 178 */ 179 struct mei_cl_cb { 180 struct list_head list; 181 struct mei_cl *cl; 182 enum mei_cb_file_ops fop_type; 183 struct mei_msg_data buf; 184 size_t buf_idx; 185 const struct file *fp; 186 int status; 187 u32 internal:1; 188 u32 blocking:1; 189 u32 completed:1; 190 }; 191 192 /** 193 * struct mei_cl - me client host representation 194 * carried in file->private_data 195 * 196 * @link: link in the clients list 197 * @dev: mei parent device 198 * @state: file operation state 199 * @tx_wait: wait queue for tx completion 200 * @rx_wait: wait queue for rx completion 201 * @wait: wait queue for management operation 202 * @ev_wait: notification wait queue 203 * @ev_async: event async notification 204 * @status: connection status 205 * @me_cl: fw client connected 206 * @fp: file associated with client 207 * @host_client_id: host id 208 * @tx_flow_ctrl_creds: transmit flow credentials 209 * @rx_flow_ctrl_creds: receive flow credentials 210 * @timer_count: watchdog timer for operation completion 211 * @notify_en: notification - enabled/disabled 212 * @notify_ev: pending notification event 213 * @tx_cb_queued: number of tx callbacks in queue 214 * @writing_state: state of the tx 215 * @rd_pending: pending read credits 216 * @rd_completed: completed read 217 * 218 * @cldev: device on the mei client bus 219 */ 220 struct mei_cl { 221 struct list_head link; 222 struct mei_device *dev; 223 enum file_state state; 224 wait_queue_head_t tx_wait; 225 wait_queue_head_t rx_wait; 226 wait_queue_head_t wait; 227 wait_queue_head_t ev_wait; 228 struct fasync_struct *ev_async; 229 int status; 230 struct mei_me_client *me_cl; 231 const struct file *fp; 232 u8 host_client_id; 233 u8 tx_flow_ctrl_creds; 234 u8 rx_flow_ctrl_creds; 235 u8 timer_count; 236 u8 notify_en; 237 u8 notify_ev; 238 u8 tx_cb_queued; 239 enum mei_file_transaction_states writing_state; 240 struct list_head rd_pending; 241 struct list_head rd_completed; 242 243 struct mei_cl_device *cldev; 244 }; 245 246 #define MEI_TX_QUEUE_LIMIT_DEFAULT 50 247 #define MEI_TX_QUEUE_LIMIT_MAX 255 248 #define MEI_TX_QUEUE_LIMIT_MIN 30 249 250 /** 251 * struct mei_hw_ops - hw specific ops 252 * 253 * @host_is_ready : query for host readiness 254 * 255 * @hw_is_ready : query if hw is ready 256 * @hw_reset : reset hw 257 * @hw_start : start hw after reset 258 * @hw_config : configure hw 259 * 260 * @fw_status : get fw status registers 261 * @pg_state : power gating state of the device 262 * @pg_in_transition : is device now in pg transition 263 * @pg_is_enabled : is power gating enabled 264 * 265 * @intr_clear : clear pending interrupts 266 * @intr_enable : enable interrupts 267 * @intr_disable : disable interrupts 268 * @synchronize_irq : synchronize irqs 269 * 270 * @hbuf_free_slots : query for write buffer empty slots 271 * @hbuf_is_ready : query if write buffer is empty 272 * @hbuf_max_len : query for write buffer max len 273 * 274 * @write : write a message to FW 275 * 276 * @rdbuf_full_slots : query how many slots are filled 277 * 278 * @read_hdr : get first 4 bytes (header) 279 * @read : read a buffer from the FW 280 */ 281 struct mei_hw_ops { 282 283 bool (*host_is_ready)(struct mei_device *dev); 284 285 bool (*hw_is_ready)(struct mei_device *dev); 286 int (*hw_reset)(struct mei_device *dev, bool enable); 287 int (*hw_start)(struct mei_device *dev); 288 void (*hw_config)(struct mei_device *dev); 289 290 int (*fw_status)(struct mei_device *dev, struct mei_fw_status *fw_sts); 291 enum mei_pg_state (*pg_state)(struct mei_device *dev); 292 bool (*pg_in_transition)(struct mei_device *dev); 293 bool (*pg_is_enabled)(struct mei_device *dev); 294 295 void (*intr_clear)(struct mei_device *dev); 296 void (*intr_enable)(struct mei_device *dev); 297 void (*intr_disable)(struct mei_device *dev); 298 void (*synchronize_irq)(struct mei_device *dev); 299 300 int (*hbuf_free_slots)(struct mei_device *dev); 301 bool (*hbuf_is_ready)(struct mei_device *dev); 302 size_t (*hbuf_max_len)(const struct mei_device *dev); 303 int (*write)(struct mei_device *dev, 304 struct mei_msg_hdr *hdr, 305 const unsigned char *buf); 306 307 int (*rdbuf_full_slots)(struct mei_device *dev); 308 309 u32 (*read_hdr)(const struct mei_device *dev); 310 int (*read)(struct mei_device *dev, 311 unsigned char *buf, unsigned long len); 312 }; 313 314 /* MEI bus API*/ 315 void mei_cl_bus_rescan_work(struct work_struct *work); 316 void mei_cl_bus_dev_fixup(struct mei_cl_device *dev); 317 ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length, 318 unsigned int mode); 319 ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length, 320 unsigned int mode, unsigned long timeout); 321 bool mei_cl_bus_rx_event(struct mei_cl *cl); 322 bool mei_cl_bus_notify_event(struct mei_cl *cl); 323 void mei_cl_bus_remove_devices(struct mei_device *bus); 324 int mei_cl_bus_init(void); 325 void mei_cl_bus_exit(void); 326 327 /** 328 * enum mei_pg_event - power gating transition events 329 * 330 * @MEI_PG_EVENT_IDLE: the driver is not in power gating transition 331 * @MEI_PG_EVENT_WAIT: the driver is waiting for a pg event to complete 332 * @MEI_PG_EVENT_RECEIVED: the driver received pg event 333 * @MEI_PG_EVENT_INTR_WAIT: the driver is waiting for a pg event interrupt 334 * @MEI_PG_EVENT_INTR_RECEIVED: the driver received pg event interrupt 335 */ 336 enum mei_pg_event { 337 MEI_PG_EVENT_IDLE, 338 MEI_PG_EVENT_WAIT, 339 MEI_PG_EVENT_RECEIVED, 340 MEI_PG_EVENT_INTR_WAIT, 341 MEI_PG_EVENT_INTR_RECEIVED, 342 }; 343 344 /** 345 * enum mei_pg_state - device internal power gating state 346 * 347 * @MEI_PG_OFF: device is not power gated - it is active 348 * @MEI_PG_ON: device is power gated - it is in lower power state 349 */ 350 enum mei_pg_state { 351 MEI_PG_OFF = 0, 352 MEI_PG_ON = 1, 353 }; 354 355 const char *mei_pg_state_str(enum mei_pg_state state); 356 357 /** 358 * struct mei_fw_version - MEI FW version struct 359 * 360 * @platform: platform identifier 361 * @major: major version field 362 * @minor: minor version field 363 * @buildno: build number version field 364 * @hotfix: hotfix number version field 365 */ 366 struct mei_fw_version { 367 u8 platform; 368 u8 major; 369 u16 minor; 370 u16 buildno; 371 u16 hotfix; 372 }; 373 374 #define MEI_MAX_FW_VER_BLOCKS 3 375 376 /** 377 * struct mei_device - MEI private device struct 378 * 379 * @dev : device on a bus 380 * @cdev : character device 381 * @minor : minor number allocated for device 382 * 383 * @write_list : write pending list 384 * @write_waiting_list : write completion list 385 * @ctrl_wr_list : pending control write list 386 * @ctrl_rd_list : pending control read list 387 * @tx_queue_limit: tx queues per client linit 388 * 389 * @file_list : list of opened handles 390 * @open_handle_count: number of opened handles 391 * 392 * @device_lock : big device lock 393 * @timer_work : MEI timer delayed work (timeouts) 394 * 395 * @recvd_hw_ready : hw ready message received flag 396 * 397 * @wait_hw_ready : wait queue for receive HW ready message form FW 398 * @wait_pg : wait queue for receive PG message from FW 399 * @wait_hbm_start : wait queue for receive HBM start message from FW 400 * 401 * @reset_count : number of consecutive resets 402 * @dev_state : device state 403 * @hbm_state : state of host bus message protocol 404 * @init_clients_timer : HBM init handshake timeout 405 * 406 * @pg_event : power gating event 407 * @pg_domain : runtime PM domain 408 * 409 * @rd_msg_buf : control messages buffer 410 * @rd_msg_hdr : read message header storage 411 * 412 * @hbuf_depth : depth of hardware host/write buffer is slots 413 * @hbuf_is_ready : query if the host host/write buffer is ready 414 * 415 * @version : HBM protocol version in use 416 * @hbm_f_pg_supported : hbm feature pgi protocol 417 * @hbm_f_dc_supported : hbm feature dynamic clients 418 * @hbm_f_dot_supported : hbm feature disconnect on timeout 419 * @hbm_f_ev_supported : hbm feature event notification 420 * @hbm_f_fa_supported : hbm feature fixed address client 421 * @hbm_f_ie_supported : hbm feature immediate reply to enum request 422 * @hbm_f_os_supported : hbm feature support OS ver message 423 * 424 * @fw_ver : FW versions 425 * 426 * @me_clients_rwsem: rw lock over me_clients list 427 * @me_clients : list of FW clients 428 * @me_clients_map : FW clients bit map 429 * @host_clients_map : host clients id pool 430 * 431 * @allow_fixed_address: allow user space to connect a fixed client 432 * @override_fixed_address: force allow fixed address behavior 433 * 434 * @reset_work : work item for the device reset 435 * @bus_rescan_work : work item for the bus rescan 436 * 437 * @device_list : mei client bus list 438 * @cl_bus_lock : client bus list lock 439 * 440 * @dbgfs_dir : debugfs mei root directory 441 * 442 * @ops: : hw specific operations 443 * @hw : hw specific data 444 */ 445 struct mei_device { 446 struct device *dev; 447 struct cdev cdev; 448 int minor; 449 450 struct list_head write_list; 451 struct list_head write_waiting_list; 452 struct list_head ctrl_wr_list; 453 struct list_head ctrl_rd_list; 454 u8 tx_queue_limit; 455 456 struct list_head file_list; 457 long open_handle_count; 458 459 struct mutex device_lock; 460 struct delayed_work timer_work; 461 462 bool recvd_hw_ready; 463 /* 464 * waiting queue for receive message from FW 465 */ 466 wait_queue_head_t wait_hw_ready; 467 wait_queue_head_t wait_pg; 468 wait_queue_head_t wait_hbm_start; 469 470 /* 471 * mei device states 472 */ 473 unsigned long reset_count; 474 enum mei_dev_state dev_state; 475 enum mei_hbm_state hbm_state; 476 u16 init_clients_timer; 477 478 /* 479 * Power Gating support 480 */ 481 enum mei_pg_event pg_event; 482 #ifdef CONFIG_PM 483 struct dev_pm_domain pg_domain; 484 #endif /* CONFIG_PM */ 485 486 unsigned char rd_msg_buf[MEI_RD_MSG_BUF_SIZE]; 487 u32 rd_msg_hdr; 488 489 /* write buffer */ 490 u8 hbuf_depth; 491 bool hbuf_is_ready; 492 493 struct hbm_version version; 494 unsigned int hbm_f_pg_supported:1; 495 unsigned int hbm_f_dc_supported:1; 496 unsigned int hbm_f_dot_supported:1; 497 unsigned int hbm_f_ev_supported:1; 498 unsigned int hbm_f_fa_supported:1; 499 unsigned int hbm_f_ie_supported:1; 500 unsigned int hbm_f_os_supported:1; 501 502 struct mei_fw_version fw_ver[MEI_MAX_FW_VER_BLOCKS]; 503 504 struct rw_semaphore me_clients_rwsem; 505 struct list_head me_clients; 506 DECLARE_BITMAP(me_clients_map, MEI_CLIENTS_MAX); 507 DECLARE_BITMAP(host_clients_map, MEI_CLIENTS_MAX); 508 509 bool allow_fixed_address; 510 bool override_fixed_address; 511 512 struct work_struct reset_work; 513 struct work_struct bus_rescan_work; 514 515 /* List of bus devices */ 516 struct list_head device_list; 517 struct mutex cl_bus_lock; 518 519 #if IS_ENABLED(CONFIG_DEBUG_FS) 520 struct dentry *dbgfs_dir; 521 #endif /* CONFIG_DEBUG_FS */ 522 523 524 const struct mei_hw_ops *ops; 525 char hw[0] __aligned(sizeof(void *)); 526 }; 527 528 static inline unsigned long mei_secs_to_jiffies(unsigned long sec) 529 { 530 return msecs_to_jiffies(sec * MSEC_PER_SEC); 531 } 532 533 /** 534 * mei_data2slots - get slots - number of (dwords) from a message length 535 * + size of the mei header 536 * 537 * @length: size of the messages in bytes 538 * 539 * Return: number of slots 540 */ 541 static inline u32 mei_data2slots(size_t length) 542 { 543 return DIV_ROUND_UP(sizeof(struct mei_msg_hdr) + length, 4); 544 } 545 546 /** 547 * mei_slots2data - get data in slots - bytes from slots 548 * 549 * @slots: number of available slots 550 * 551 * Return: number of bytes in slots 552 */ 553 static inline u32 mei_slots2data(int slots) 554 { 555 return slots * 4; 556 } 557 558 /* 559 * mei init function prototypes 560 */ 561 void mei_device_init(struct mei_device *dev, 562 struct device *device, 563 const struct mei_hw_ops *hw_ops); 564 int mei_reset(struct mei_device *dev); 565 int mei_start(struct mei_device *dev); 566 int mei_restart(struct mei_device *dev); 567 void mei_stop(struct mei_device *dev); 568 void mei_cancel_work(struct mei_device *dev); 569 570 /* 571 * MEI interrupt functions prototype 572 */ 573 574 void mei_timer(struct work_struct *work); 575 void mei_schedule_stall_timer(struct mei_device *dev); 576 int mei_irq_read_handler(struct mei_device *dev, 577 struct list_head *cmpl_list, s32 *slots); 578 579 int mei_irq_write_handler(struct mei_device *dev, struct list_head *cmpl_list); 580 void mei_irq_compl_handler(struct mei_device *dev, struct list_head *cmpl_list); 581 582 /* 583 * Register Access Function 584 */ 585 586 587 static inline void mei_hw_config(struct mei_device *dev) 588 { 589 dev->ops->hw_config(dev); 590 } 591 592 static inline enum mei_pg_state mei_pg_state(struct mei_device *dev) 593 { 594 return dev->ops->pg_state(dev); 595 } 596 597 static inline bool mei_pg_in_transition(struct mei_device *dev) 598 { 599 return dev->ops->pg_in_transition(dev); 600 } 601 602 static inline bool mei_pg_is_enabled(struct mei_device *dev) 603 { 604 return dev->ops->pg_is_enabled(dev); 605 } 606 607 static inline int mei_hw_reset(struct mei_device *dev, bool enable) 608 { 609 return dev->ops->hw_reset(dev, enable); 610 } 611 612 static inline int mei_hw_start(struct mei_device *dev) 613 { 614 return dev->ops->hw_start(dev); 615 } 616 617 static inline void mei_clear_interrupts(struct mei_device *dev) 618 { 619 dev->ops->intr_clear(dev); 620 } 621 622 static inline void mei_enable_interrupts(struct mei_device *dev) 623 { 624 dev->ops->intr_enable(dev); 625 } 626 627 static inline void mei_disable_interrupts(struct mei_device *dev) 628 { 629 dev->ops->intr_disable(dev); 630 } 631 632 static inline void mei_synchronize_irq(struct mei_device *dev) 633 { 634 dev->ops->synchronize_irq(dev); 635 } 636 637 static inline bool mei_host_is_ready(struct mei_device *dev) 638 { 639 return dev->ops->host_is_ready(dev); 640 } 641 static inline bool mei_hw_is_ready(struct mei_device *dev) 642 { 643 return dev->ops->hw_is_ready(dev); 644 } 645 646 static inline bool mei_hbuf_is_ready(struct mei_device *dev) 647 { 648 return dev->ops->hbuf_is_ready(dev); 649 } 650 651 static inline int mei_hbuf_empty_slots(struct mei_device *dev) 652 { 653 return dev->ops->hbuf_free_slots(dev); 654 } 655 656 static inline size_t mei_hbuf_max_len(const struct mei_device *dev) 657 { 658 return dev->ops->hbuf_max_len(dev); 659 } 660 661 static inline int mei_write_message(struct mei_device *dev, 662 struct mei_msg_hdr *hdr, const void *buf) 663 { 664 return dev->ops->write(dev, hdr, buf); 665 } 666 667 static inline u32 mei_read_hdr(const struct mei_device *dev) 668 { 669 return dev->ops->read_hdr(dev); 670 } 671 672 static inline void mei_read_slots(struct mei_device *dev, 673 unsigned char *buf, unsigned long len) 674 { 675 dev->ops->read(dev, buf, len); 676 } 677 678 static inline int mei_count_full_read_slots(struct mei_device *dev) 679 { 680 return dev->ops->rdbuf_full_slots(dev); 681 } 682 683 static inline int mei_fw_status(struct mei_device *dev, 684 struct mei_fw_status *fw_status) 685 { 686 return dev->ops->fw_status(dev, fw_status); 687 } 688 689 bool mei_hbuf_acquire(struct mei_device *dev); 690 691 bool mei_write_is_idle(struct mei_device *dev); 692 693 #if IS_ENABLED(CONFIG_DEBUG_FS) 694 int mei_dbgfs_register(struct mei_device *dev, const char *name); 695 void mei_dbgfs_deregister(struct mei_device *dev); 696 #else 697 static inline int mei_dbgfs_register(struct mei_device *dev, const char *name) 698 { 699 return 0; 700 } 701 static inline void mei_dbgfs_deregister(struct mei_device *dev) {} 702 #endif /* CONFIG_DEBUG_FS */ 703 704 int mei_register(struct mei_device *dev, struct device *parent); 705 void mei_deregister(struct mei_device *dev); 706 707 #define MEI_HDR_FMT "hdr:host=%02d me=%02d len=%d internal=%1d comp=%1d" 708 #define MEI_HDR_PRM(hdr) \ 709 (hdr)->host_addr, (hdr)->me_addr, \ 710 (hdr)->length, (hdr)->internal, (hdr)->msg_complete 711 712 ssize_t mei_fw_status2str(struct mei_fw_status *fw_sts, char *buf, size_t len); 713 /** 714 * mei_fw_status_str - fetch and convert fw status registers to printable string 715 * 716 * @dev: the device structure 717 * @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ 718 * @len: buffer len must be >= MEI_FW_STATUS_STR_SZ 719 * 720 * Return: number of bytes written or < 0 on failure 721 */ 722 static inline ssize_t mei_fw_status_str(struct mei_device *dev, 723 char *buf, size_t len) 724 { 725 struct mei_fw_status fw_status; 726 int ret; 727 728 buf[0] = '\0'; 729 730 ret = mei_fw_status(dev, &fw_status); 731 if (ret) 732 return ret; 733 734 ret = mei_fw_status2str(&fw_status, buf, MEI_FW_STATUS_STR_SZ); 735 736 return ret; 737 } 738 739 740 #endif 741