1 /* 2 * 3 * Intel Management Engine Interface (Intel MEI) Linux driver 4 * Copyright (c) 2003-2012, 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 30 /* 31 * AMTHI Client UUID 32 */ 33 extern const uuid_le mei_amthif_guid; 34 35 #define MEI_RD_MSG_BUF_SIZE (128 * sizeof(u32)) 36 37 /* 38 * Number of Maximum MEI Clients 39 */ 40 #define MEI_CLIENTS_MAX 256 41 42 /* 43 * maximum number of consecutive resets 44 */ 45 #define MEI_MAX_CONSEC_RESET 3 46 47 /* 48 * Number of File descriptors/handles 49 * that can be opened to the driver. 50 * 51 * Limit to 255: 256 Total Clients 52 * minus internal client for MEI Bus Messages 53 */ 54 #define MEI_MAX_OPEN_HANDLE_COUNT (MEI_CLIENTS_MAX - 1) 55 56 /* File state */ 57 enum file_state { 58 MEI_FILE_INITIALIZING = 0, 59 MEI_FILE_CONNECTING, 60 MEI_FILE_CONNECTED, 61 MEI_FILE_DISCONNECTING, 62 MEI_FILE_DISCONNECT_REPLY, 63 MEI_FILE_DISCONNECT_REQUIRED, 64 MEI_FILE_DISCONNECTED, 65 }; 66 67 /* MEI device states */ 68 enum mei_dev_state { 69 MEI_DEV_INITIALIZING = 0, 70 MEI_DEV_INIT_CLIENTS, 71 MEI_DEV_ENABLED, 72 MEI_DEV_RESETTING, 73 MEI_DEV_DISABLED, 74 MEI_DEV_POWER_DOWN, 75 MEI_DEV_POWER_UP 76 }; 77 78 const char *mei_dev_state_str(int state); 79 80 enum iamthif_states { 81 MEI_IAMTHIF_IDLE, 82 MEI_IAMTHIF_WRITING, 83 MEI_IAMTHIF_READING, 84 }; 85 86 enum mei_file_transaction_states { 87 MEI_IDLE, 88 MEI_WRITING, 89 MEI_WRITE_COMPLETE, 90 }; 91 92 /** 93 * enum mei_cb_file_ops - file operation associated with the callback 94 * @MEI_FOP_READ: read 95 * @MEI_FOP_WRITE: write 96 * @MEI_FOP_CONNECT: connect 97 * @MEI_FOP_DISCONNECT: disconnect 98 * @MEI_FOP_DISCONNECT_RSP: disconnect response 99 * @MEI_FOP_NOTIFY_START: start notification 100 * @MEI_FOP_NOTIFY_STOP: stop notification 101 */ 102 enum mei_cb_file_ops { 103 MEI_FOP_READ = 0, 104 MEI_FOP_WRITE, 105 MEI_FOP_CONNECT, 106 MEI_FOP_DISCONNECT, 107 MEI_FOP_DISCONNECT_RSP, 108 MEI_FOP_NOTIFY_START, 109 MEI_FOP_NOTIFY_STOP, 110 }; 111 112 /* 113 * Intel MEI message data struct 114 */ 115 struct mei_msg_data { 116 size_t size; 117 unsigned char *data; 118 }; 119 120 /* Maximum number of processed FW status registers */ 121 #define MEI_FW_STATUS_MAX 6 122 /* Minimal buffer for FW status string (8 bytes in dw + space or '\0') */ 123 #define MEI_FW_STATUS_STR_SZ (MEI_FW_STATUS_MAX * (8 + 1)) 124 125 126 /* 127 * struct mei_fw_status - storage of FW status data 128 * 129 * @count: number of actually available elements in array 130 * @status: FW status registers 131 */ 132 struct mei_fw_status { 133 int count; 134 u32 status[MEI_FW_STATUS_MAX]; 135 }; 136 137 /** 138 * struct mei_me_client - representation of me (fw) client 139 * 140 * @list: link in me client list 141 * @refcnt: struct reference count 142 * @props: client properties 143 * @client_id: me client id 144 * @tx_flow_ctrl_creds: flow control credits 145 * @connect_count: number connections to this client 146 * @bus_added: added to bus 147 */ 148 struct mei_me_client { 149 struct list_head list; 150 struct kref refcnt; 151 struct mei_client_properties props; 152 u8 client_id; 153 u8 tx_flow_ctrl_creds; 154 u8 connect_count; 155 u8 bus_added; 156 }; 157 158 159 struct mei_cl; 160 161 /** 162 * struct mei_cl_cb - file operation callback structure 163 * 164 * @list: link in callback queue 165 * @cl: file client who is running this operation 166 * @fop_type: file operation type 167 * @buf: buffer for data associated with the callback 168 * @buf_idx: last read index 169 * @fp: pointer to file structure 170 * @status: io status of the cb 171 * @internal: communication between driver and FW flag 172 * @completed: the transfer or reception has completed 173 */ 174 struct mei_cl_cb { 175 struct list_head list; 176 struct mei_cl *cl; 177 enum mei_cb_file_ops fop_type; 178 struct mei_msg_data buf; 179 size_t buf_idx; 180 const struct file *fp; 181 int status; 182 u32 internal:1; 183 u32 completed:1; 184 }; 185 186 /** 187 * struct mei_cl - me client host representation 188 * carried in file->private_data 189 * 190 * @link: link in the clients list 191 * @dev: mei parent device 192 * @state: file operation state 193 * @tx_wait: wait queue for tx completion 194 * @rx_wait: wait queue for rx completion 195 * @wait: wait queue for management operation 196 * @ev_wait: notification wait queue 197 * @ev_async: event async notification 198 * @status: connection status 199 * @me_cl: fw client connected 200 * @fp: file associated with client 201 * @host_client_id: host id 202 * @tx_flow_ctrl_creds: transmit flow credentials 203 * @rx_flow_ctrl_creds: receive flow credentials 204 * @timer_count: watchdog timer for operation completion 205 * @notify_en: notification - enabled/disabled 206 * @notify_ev: pending notification event 207 * @writing_state: state of the tx 208 * @rd_pending: pending read credits 209 * @rd_completed: completed read 210 * 211 * @cldev: device on the mei client bus 212 */ 213 struct mei_cl { 214 struct list_head link; 215 struct mei_device *dev; 216 enum file_state state; 217 wait_queue_head_t tx_wait; 218 wait_queue_head_t rx_wait; 219 wait_queue_head_t wait; 220 wait_queue_head_t ev_wait; 221 struct fasync_struct *ev_async; 222 int status; 223 struct mei_me_client *me_cl; 224 const struct file *fp; 225 u8 host_client_id; 226 u8 tx_flow_ctrl_creds; 227 u8 rx_flow_ctrl_creds; 228 u8 timer_count; 229 u8 notify_en; 230 u8 notify_ev; 231 enum mei_file_transaction_states writing_state; 232 struct list_head rd_pending; 233 struct list_head rd_completed; 234 235 struct mei_cl_device *cldev; 236 }; 237 238 /** 239 * struct mei_hw_ops - hw specific ops 240 * 241 * @host_is_ready : query for host readiness 242 * 243 * @hw_is_ready : query if hw is ready 244 * @hw_reset : reset hw 245 * @hw_start : start hw after reset 246 * @hw_config : configure hw 247 * 248 * @fw_status : get fw status registers 249 * @pg_state : power gating state of the device 250 * @pg_in_transition : is device now in pg transition 251 * @pg_is_enabled : is power gating enabled 252 * 253 * @intr_clear : clear pending interrupts 254 * @intr_enable : enable interrupts 255 * @intr_disable : disable interrupts 256 * 257 * @hbuf_free_slots : query for write buffer empty slots 258 * @hbuf_is_ready : query if write buffer is empty 259 * @hbuf_max_len : query for write buffer max len 260 * 261 * @write : write a message to FW 262 * 263 * @rdbuf_full_slots : query how many slots are filled 264 * 265 * @read_hdr : get first 4 bytes (header) 266 * @read : read a buffer from the FW 267 */ 268 struct mei_hw_ops { 269 270 bool (*host_is_ready)(struct mei_device *dev); 271 272 bool (*hw_is_ready)(struct mei_device *dev); 273 int (*hw_reset)(struct mei_device *dev, bool enable); 274 int (*hw_start)(struct mei_device *dev); 275 void (*hw_config)(struct mei_device *dev); 276 277 278 int (*fw_status)(struct mei_device *dev, struct mei_fw_status *fw_sts); 279 enum mei_pg_state (*pg_state)(struct mei_device *dev); 280 bool (*pg_in_transition)(struct mei_device *dev); 281 bool (*pg_is_enabled)(struct mei_device *dev); 282 283 void (*intr_clear)(struct mei_device *dev); 284 void (*intr_enable)(struct mei_device *dev); 285 void (*intr_disable)(struct mei_device *dev); 286 287 int (*hbuf_free_slots)(struct mei_device *dev); 288 bool (*hbuf_is_ready)(struct mei_device *dev); 289 size_t (*hbuf_max_len)(const struct mei_device *dev); 290 291 int (*write)(struct mei_device *dev, 292 struct mei_msg_hdr *hdr, 293 unsigned char *buf); 294 295 int (*rdbuf_full_slots)(struct mei_device *dev); 296 297 u32 (*read_hdr)(const struct mei_device *dev); 298 int (*read)(struct mei_device *dev, 299 unsigned char *buf, unsigned long len); 300 }; 301 302 /* MEI bus API*/ 303 void mei_cl_bus_rescan(struct mei_device *bus); 304 void mei_cl_bus_rescan_work(struct work_struct *work); 305 void mei_cl_bus_dev_fixup(struct mei_cl_device *dev); 306 ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length, 307 bool blocking); 308 ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length); 309 bool mei_cl_bus_rx_event(struct mei_cl *cl); 310 bool mei_cl_bus_notify_event(struct mei_cl *cl); 311 void mei_cl_bus_remove_devices(struct mei_device *bus); 312 int mei_cl_bus_init(void); 313 void mei_cl_bus_exit(void); 314 315 /** 316 * enum mei_pg_event - power gating transition events 317 * 318 * @MEI_PG_EVENT_IDLE: the driver is not in power gating transition 319 * @MEI_PG_EVENT_WAIT: the driver is waiting for a pg event to complete 320 * @MEI_PG_EVENT_RECEIVED: the driver received pg event 321 * @MEI_PG_EVENT_INTR_WAIT: the driver is waiting for a pg event interrupt 322 * @MEI_PG_EVENT_INTR_RECEIVED: the driver received pg event interrupt 323 */ 324 enum mei_pg_event { 325 MEI_PG_EVENT_IDLE, 326 MEI_PG_EVENT_WAIT, 327 MEI_PG_EVENT_RECEIVED, 328 MEI_PG_EVENT_INTR_WAIT, 329 MEI_PG_EVENT_INTR_RECEIVED, 330 }; 331 332 /** 333 * enum mei_pg_state - device internal power gating state 334 * 335 * @MEI_PG_OFF: device is not power gated - it is active 336 * @MEI_PG_ON: device is power gated - it is in lower power state 337 */ 338 enum mei_pg_state { 339 MEI_PG_OFF = 0, 340 MEI_PG_ON = 1, 341 }; 342 343 const char *mei_pg_state_str(enum mei_pg_state state); 344 345 /** 346 * struct mei_device - MEI private device struct 347 * 348 * @dev : device on a bus 349 * @cdev : character device 350 * @minor : minor number allocated for device 351 * 352 * @write_list : write pending list 353 * @write_waiting_list : write completion list 354 * @ctrl_wr_list : pending control write list 355 * @ctrl_rd_list : pending control read list 356 * 357 * @file_list : list of opened handles 358 * @open_handle_count: number of opened handles 359 * 360 * @device_lock : big device lock 361 * @timer_work : MEI timer delayed work (timeouts) 362 * 363 * @recvd_hw_ready : hw ready message received flag 364 * 365 * @wait_hw_ready : wait queue for receive HW ready message form FW 366 * @wait_pg : wait queue for receive PG message from FW 367 * @wait_hbm_start : wait queue for receive HBM start message from FW 368 * 369 * @reset_count : number of consecutive resets 370 * @dev_state : device state 371 * @hbm_state : state of host bus message protocol 372 * @init_clients_timer : HBM init handshake timeout 373 * 374 * @pg_event : power gating event 375 * @pg_domain : runtime PM domain 376 * 377 * @rd_msg_buf : control messages buffer 378 * @rd_msg_hdr : read message header storage 379 * 380 * @hbuf_depth : depth of hardware host/write buffer is slots 381 * @hbuf_is_ready : query if the host host/write buffer is ready 382 * 383 * @version : HBM protocol version in use 384 * @hbm_f_pg_supported : hbm feature pgi protocol 385 * @hbm_f_dc_supported : hbm feature dynamic clients 386 * @hbm_f_dot_supported : hbm feature disconnect on timeout 387 * @hbm_f_ev_supported : hbm feature event notification 388 * @hbm_f_fa_supported : hbm feature fixed address client 389 * @hbm_f_ie_supported : hbm feature immediate reply to enum request 390 * 391 * @me_clients_rwsem: rw lock over me_clients list 392 * @me_clients : list of FW clients 393 * @me_clients_map : FW clients bit map 394 * @host_clients_map : host clients id pool 395 * 396 * @allow_fixed_address: allow user space to connect a fixed client 397 * @override_fixed_address: force allow fixed address behavior 398 * 399 * @amthif_cmd_list : amthif list for cmd waiting 400 * @iamthif_cl : amthif host client 401 * @iamthif_open_count : number of opened amthif connections 402 * @iamthif_stall_timer : timer to detect amthif hang 403 * @iamthif_state : amthif processor state 404 * @iamthif_canceled : current amthif command is canceled 405 * 406 * @reset_work : work item for the device reset 407 * @bus_rescan_work : work item for the bus rescan 408 * 409 * @device_list : mei client bus list 410 * @cl_bus_lock : client bus list lock 411 * 412 * @dbgfs_dir : debugfs mei root directory 413 * 414 * @ops: : hw specific operations 415 * @hw : hw specific data 416 */ 417 struct mei_device { 418 struct device *dev; 419 struct cdev cdev; 420 int minor; 421 422 struct mei_cl_cb write_list; 423 struct mei_cl_cb write_waiting_list; 424 struct mei_cl_cb ctrl_wr_list; 425 struct mei_cl_cb ctrl_rd_list; 426 427 struct list_head file_list; 428 long open_handle_count; 429 430 struct mutex device_lock; 431 struct delayed_work timer_work; 432 433 bool recvd_hw_ready; 434 /* 435 * waiting queue for receive message from FW 436 */ 437 wait_queue_head_t wait_hw_ready; 438 wait_queue_head_t wait_pg; 439 wait_queue_head_t wait_hbm_start; 440 441 /* 442 * mei device states 443 */ 444 unsigned long reset_count; 445 enum mei_dev_state dev_state; 446 enum mei_hbm_state hbm_state; 447 u16 init_clients_timer; 448 449 /* 450 * Power Gating support 451 */ 452 enum mei_pg_event pg_event; 453 #ifdef CONFIG_PM 454 struct dev_pm_domain pg_domain; 455 #endif /* CONFIG_PM */ 456 457 unsigned char rd_msg_buf[MEI_RD_MSG_BUF_SIZE]; 458 u32 rd_msg_hdr; 459 460 /* write buffer */ 461 u8 hbuf_depth; 462 bool hbuf_is_ready; 463 464 struct hbm_version version; 465 unsigned int hbm_f_pg_supported:1; 466 unsigned int hbm_f_dc_supported:1; 467 unsigned int hbm_f_dot_supported:1; 468 unsigned int hbm_f_ev_supported:1; 469 unsigned int hbm_f_fa_supported:1; 470 unsigned int hbm_f_ie_supported:1; 471 472 struct rw_semaphore me_clients_rwsem; 473 struct list_head me_clients; 474 DECLARE_BITMAP(me_clients_map, MEI_CLIENTS_MAX); 475 DECLARE_BITMAP(host_clients_map, MEI_CLIENTS_MAX); 476 477 bool allow_fixed_address; 478 bool override_fixed_address; 479 480 /* amthif list for cmd waiting */ 481 struct mei_cl_cb amthif_cmd_list; 482 struct mei_cl iamthif_cl; 483 long iamthif_open_count; 484 u32 iamthif_stall_timer; 485 enum iamthif_states iamthif_state; 486 bool iamthif_canceled; 487 488 struct work_struct reset_work; 489 struct work_struct bus_rescan_work; 490 491 /* List of bus devices */ 492 struct list_head device_list; 493 struct mutex cl_bus_lock; 494 495 #if IS_ENABLED(CONFIG_DEBUG_FS) 496 struct dentry *dbgfs_dir; 497 #endif /* CONFIG_DEBUG_FS */ 498 499 500 const struct mei_hw_ops *ops; 501 char hw[0] __aligned(sizeof(void *)); 502 }; 503 504 static inline unsigned long mei_secs_to_jiffies(unsigned long sec) 505 { 506 return msecs_to_jiffies(sec * MSEC_PER_SEC); 507 } 508 509 /** 510 * mei_data2slots - get slots - number of (dwords) from a message length 511 * + size of the mei header 512 * 513 * @length: size of the messages in bytes 514 * 515 * Return: number of slots 516 */ 517 static inline u32 mei_data2slots(size_t length) 518 { 519 return DIV_ROUND_UP(sizeof(struct mei_msg_hdr) + length, 4); 520 } 521 522 /** 523 * mei_slots2data - get data in slots - bytes from slots 524 * 525 * @slots: number of available slots 526 * 527 * Return: number of bytes in slots 528 */ 529 static inline u32 mei_slots2data(int slots) 530 { 531 return slots * 4; 532 } 533 534 /* 535 * mei init function prototypes 536 */ 537 void mei_device_init(struct mei_device *dev, 538 struct device *device, 539 const struct mei_hw_ops *hw_ops); 540 int mei_reset(struct mei_device *dev); 541 int mei_start(struct mei_device *dev); 542 int mei_restart(struct mei_device *dev); 543 void mei_stop(struct mei_device *dev); 544 void mei_cancel_work(struct mei_device *dev); 545 546 /* 547 * MEI interrupt functions prototype 548 */ 549 550 void mei_timer(struct work_struct *work); 551 void mei_schedule_stall_timer(struct mei_device *dev); 552 int mei_irq_read_handler(struct mei_device *dev, 553 struct mei_cl_cb *cmpl_list, s32 *slots); 554 555 int mei_irq_write_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list); 556 void mei_irq_compl_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list); 557 558 /* 559 * AMTHIF - AMT Host Interface Functions 560 */ 561 void mei_amthif_reset_params(struct mei_device *dev); 562 563 int mei_amthif_host_init(struct mei_device *dev, struct mei_me_client *me_cl); 564 565 unsigned int mei_amthif_poll(struct file *file, poll_table *wait); 566 567 int mei_amthif_release(struct mei_device *dev, struct file *file); 568 569 int mei_amthif_write(struct mei_cl *cl, struct mei_cl_cb *cb); 570 int mei_amthif_run_next_cmd(struct mei_device *dev); 571 int mei_amthif_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb, 572 struct mei_cl_cb *cmpl_list); 573 574 void mei_amthif_complete(struct mei_cl *cl, struct mei_cl_cb *cb); 575 int mei_amthif_irq_read_msg(struct mei_cl *cl, 576 struct mei_msg_hdr *mei_hdr, 577 struct mei_cl_cb *complete_list); 578 int mei_amthif_irq_read(struct mei_device *dev, s32 *slots); 579 580 /* 581 * Register Access Function 582 */ 583 584 585 static inline void mei_hw_config(struct mei_device *dev) 586 { 587 dev->ops->hw_config(dev); 588 } 589 590 static inline enum mei_pg_state mei_pg_state(struct mei_device *dev) 591 { 592 return dev->ops->pg_state(dev); 593 } 594 595 static inline bool mei_pg_in_transition(struct mei_device *dev) 596 { 597 return dev->ops->pg_in_transition(dev); 598 } 599 600 static inline bool mei_pg_is_enabled(struct mei_device *dev) 601 { 602 return dev->ops->pg_is_enabled(dev); 603 } 604 605 static inline int mei_hw_reset(struct mei_device *dev, bool enable) 606 { 607 return dev->ops->hw_reset(dev, enable); 608 } 609 610 static inline int mei_hw_start(struct mei_device *dev) 611 { 612 return dev->ops->hw_start(dev); 613 } 614 615 static inline void mei_clear_interrupts(struct mei_device *dev) 616 { 617 dev->ops->intr_clear(dev); 618 } 619 620 static inline void mei_enable_interrupts(struct mei_device *dev) 621 { 622 dev->ops->intr_enable(dev); 623 } 624 625 static inline void mei_disable_interrupts(struct mei_device *dev) 626 { 627 dev->ops->intr_disable(dev); 628 } 629 630 static inline bool mei_host_is_ready(struct mei_device *dev) 631 { 632 return dev->ops->host_is_ready(dev); 633 } 634 static inline bool mei_hw_is_ready(struct mei_device *dev) 635 { 636 return dev->ops->hw_is_ready(dev); 637 } 638 639 static inline bool mei_hbuf_is_ready(struct mei_device *dev) 640 { 641 return dev->ops->hbuf_is_ready(dev); 642 } 643 644 static inline int mei_hbuf_empty_slots(struct mei_device *dev) 645 { 646 return dev->ops->hbuf_free_slots(dev); 647 } 648 649 static inline size_t mei_hbuf_max_len(const struct mei_device *dev) 650 { 651 return dev->ops->hbuf_max_len(dev); 652 } 653 654 static inline int mei_write_message(struct mei_device *dev, 655 struct mei_msg_hdr *hdr, void *buf) 656 { 657 return dev->ops->write(dev, hdr, buf); 658 } 659 660 static inline u32 mei_read_hdr(const struct mei_device *dev) 661 { 662 return dev->ops->read_hdr(dev); 663 } 664 665 static inline void mei_read_slots(struct mei_device *dev, 666 unsigned char *buf, unsigned long len) 667 { 668 dev->ops->read(dev, buf, len); 669 } 670 671 static inline int mei_count_full_read_slots(struct mei_device *dev) 672 { 673 return dev->ops->rdbuf_full_slots(dev); 674 } 675 676 static inline int mei_fw_status(struct mei_device *dev, 677 struct mei_fw_status *fw_status) 678 { 679 return dev->ops->fw_status(dev, fw_status); 680 } 681 682 bool mei_hbuf_acquire(struct mei_device *dev); 683 684 bool mei_write_is_idle(struct mei_device *dev); 685 686 void mei_irq_discard_msg(struct mei_device *dev, struct mei_msg_hdr *hdr); 687 688 #if IS_ENABLED(CONFIG_DEBUG_FS) 689 int mei_dbgfs_register(struct mei_device *dev, const char *name); 690 void mei_dbgfs_deregister(struct mei_device *dev); 691 #else 692 static inline int mei_dbgfs_register(struct mei_device *dev, const char *name) 693 { 694 return 0; 695 } 696 static inline void mei_dbgfs_deregister(struct mei_device *dev) {} 697 #endif /* CONFIG_DEBUG_FS */ 698 699 int mei_register(struct mei_device *dev, struct device *parent); 700 void mei_deregister(struct mei_device *dev); 701 702 #define MEI_HDR_FMT "hdr:host=%02d me=%02d len=%d internal=%1d comp=%1d" 703 #define MEI_HDR_PRM(hdr) \ 704 (hdr)->host_addr, (hdr)->me_addr, \ 705 (hdr)->length, (hdr)->internal, (hdr)->msg_complete 706 707 ssize_t mei_fw_status2str(struct mei_fw_status *fw_sts, char *buf, size_t len); 708 /** 709 * mei_fw_status_str - fetch and convert fw status registers to printable string 710 * 711 * @dev: the device structure 712 * @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ 713 * @len: buffer len must be >= MEI_FW_STATUS_STR_SZ 714 * 715 * Return: number of bytes written or < 0 on failure 716 */ 717 static inline ssize_t mei_fw_status_str(struct mei_device *dev, 718 char *buf, size_t len) 719 { 720 struct mei_fw_status fw_status; 721 int ret; 722 723 buf[0] = '\0'; 724 725 ret = mei_fw_status(dev, &fw_status); 726 if (ret) 727 return ret; 728 729 ret = mei_fw_status2str(&fw_status, buf, MEI_FW_STATUS_STR_SZ); 730 731 return ret; 732 } 733 734 735 #endif 736