1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * The driver for BMC side of SSIF interface 4 * 5 * Copyright (c) 2022, Ampere Computing LLC 6 * 7 */ 8 9#include <linux/i2c.h> 10#include <linux/miscdevice.h> 11#include <linux/module.h> 12#include <linux/of.h> 13#include <linux/platform_device.h> 14#include <linux/poll.h> 15#include <linux/sched.h> 16#include <linux/mutex.h> 17#include <linux/spinlock.h> 18#include <linux/timer.h> 19#include <linux/jiffies.h> 20#include <linux/ipmi_ssif_bmc.h> 21 22#define DEVICE_NAME "ipmi-ssif-host" 23 24#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff) 25 26/* A standard SMBus Transaction is limited to 32 data bytes */ 27#define MAX_PAYLOAD_PER_TRANSACTION 32 28/* Transaction includes the address, the command, the length and the PEC byte */ 29#define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4) 30 31#define MAX_IPMI_DATA_PER_START_TRANSACTION 30 32#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31 33 34#define SSIF_IPMI_SINGLEPART_WRITE 0x2 35#define SSIF_IPMI_SINGLEPART_READ 0x3 36#define SSIF_IPMI_MULTIPART_WRITE_START 0x6 37#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7 38#define SSIF_IPMI_MULTIPART_WRITE_END 0x8 39#define SSIF_IPMI_MULTIPART_READ_START 0x3 40#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9 41 42/* 43 * IPMI 2.0 Spec, section 12.7 SSIF Timing, 44 * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms 45 * Recover ssif_bmc from busy state if it takes up to 500ms 46 */ 47#define RESPONSE_TIMEOUT 500 /* ms */ 48 49struct ssif_part_buffer { 50 u8 address; 51 u8 smbus_cmd; 52 u8 length; 53 u8 payload[MAX_PAYLOAD_PER_TRANSACTION]; 54 u8 pec; 55 u8 index; 56}; 57 58/* 59 * SSIF internal states: 60 * SSIF_READY 0x00 : Ready state 61 * SSIF_START 0x01 : Start smbus transaction 62 * SSIF_SMBUS_CMD 0x02 : Received SMBus command 63 * SSIF_REQ_RECVING 0x03 : Receiving request 64 * SSIF_RES_SENDING 0x04 : Sending response 65 * SSIF_ABORTING 0x05 : Aborting state 66 */ 67enum ssif_state { 68 SSIF_READY, 69 SSIF_START, 70 SSIF_SMBUS_CMD, 71 SSIF_REQ_RECVING, 72 SSIF_RES_SENDING, 73 SSIF_ABORTING, 74 SSIF_STATE_MAX 75}; 76 77struct ssif_bmc_ctx { 78 struct i2c_client *client; 79 struct miscdevice miscdev; 80 int msg_idx; 81 bool pec_support; 82 /* ssif bmc spinlock */ 83 spinlock_t lock; 84 wait_queue_head_t wait_queue; 85 u8 running; 86 enum ssif_state state; 87 /* Timeout waiting for response */ 88 struct timer_list response_timer; 89 bool response_timer_inited; 90 /* Flag to identify a Multi-part Read Transaction */ 91 bool is_singlepart_read; 92 u8 nbytes_processed; 93 u8 remain_len; 94 u8 recv_len; 95 /* Block Number of a Multi-part Read Transaction */ 96 u8 block_num; 97 bool request_available; 98 bool response_in_progress; 99 bool busy; 100 bool aborting; 101 /* Buffer for SSIF Transaction part*/ 102 struct ssif_part_buffer part_buf; 103 struct ipmi_ssif_msg response; 104 struct ipmi_ssif_msg request; 105}; 106 107static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file) 108{ 109 return container_of(file->private_data, struct ssif_bmc_ctx, miscdev); 110} 111 112static const char *state_to_string(enum ssif_state state) 113{ 114 switch (state) { 115 case SSIF_READY: 116 return "SSIF_READY"; 117 case SSIF_START: 118 return "SSIF_START"; 119 case SSIF_SMBUS_CMD: 120 return "SSIF_SMBUS_CMD"; 121 case SSIF_REQ_RECVING: 122 return "SSIF_REQ_RECVING"; 123 case SSIF_RES_SENDING: 124 return "SSIF_RES_SENDING"; 125 case SSIF_ABORTING: 126 return "SSIF_ABORTING"; 127 default: 128 return "SSIF_STATE_UNKNOWN"; 129 } 130} 131 132/* Handle SSIF message that will be sent to user */ 133static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 134{ 135 struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); 136 struct ipmi_ssif_msg msg; 137 unsigned long flags; 138 ssize_t ret; 139 140 spin_lock_irqsave(&ssif_bmc->lock, flags); 141 while (!ssif_bmc->request_available) { 142 spin_unlock_irqrestore(&ssif_bmc->lock, flags); 143 if (file->f_flags & O_NONBLOCK) 144 return -EAGAIN; 145 ret = wait_event_interruptible(ssif_bmc->wait_queue, 146 ssif_bmc->request_available); 147 if (ret) 148 return ret; 149 spin_lock_irqsave(&ssif_bmc->lock, flags); 150 } 151 152 if (count < min_t(ssize_t, 153 sizeof_field(struct ipmi_ssif_msg, len) + ssif_bmc->request.len, 154 sizeof(struct ipmi_ssif_msg))) { 155 spin_unlock_irqrestore(&ssif_bmc->lock, flags); 156 ret = -EINVAL; 157 } else { 158 count = min_t(ssize_t, 159 sizeof_field(struct ipmi_ssif_msg, len) + ssif_bmc->request.len, 160 sizeof(struct ipmi_ssif_msg)); 161 memcpy(&msg, &ssif_bmc->request, count); 162 ssif_bmc->request_available = false; 163 spin_unlock_irqrestore(&ssif_bmc->lock, flags); 164 165 ret = copy_to_user(buf, &msg, count); 166 } 167 168 return (ret < 0) ? ret : count; 169} 170 171/* Handle SSIF message that is written by user */ 172static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count, 173 loff_t *ppos) 174{ 175 struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); 176 struct ipmi_ssif_msg msg; 177 unsigned long flags; 178 ssize_t ret; 179 180 if (count > sizeof(struct ipmi_ssif_msg)) 181 return -EINVAL; 182 183 if (copy_from_user(&msg, buf, count)) 184 return -EFAULT; 185 186 if (!msg.len || count < sizeof_field(struct ipmi_ssif_msg, len) + msg.len) 187 return -EINVAL; 188 189 spin_lock_irqsave(&ssif_bmc->lock, flags); 190 while (ssif_bmc->response_in_progress) { 191 spin_unlock_irqrestore(&ssif_bmc->lock, flags); 192 if (file->f_flags & O_NONBLOCK) 193 return -EAGAIN; 194 ret = wait_event_interruptible(ssif_bmc->wait_queue, 195 !ssif_bmc->response_in_progress); 196 if (ret) 197 return ret; 198 spin_lock_irqsave(&ssif_bmc->lock, flags); 199 } 200 201 /* 202 * The write must complete before the response timeout fired, otherwise 203 * the response is aborted and wait for next request 204 * Return -EINVAL if the response is aborted 205 */ 206 ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL; 207 if (ret) 208 goto exit; 209 210 del_timer(&ssif_bmc->response_timer); 211 ssif_bmc->response_timer_inited = false; 212 213 memcpy(&ssif_bmc->response, &msg, count); 214 ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION); 215 216 ssif_bmc->response_in_progress = true; 217 218 /* ssif_bmc not busy */ 219 ssif_bmc->busy = false; 220 221 /* Clean old request buffer */ 222 memset(&ssif_bmc->request, 0, sizeof(struct ipmi_ssif_msg)); 223exit: 224 spin_unlock_irqrestore(&ssif_bmc->lock, flags); 225 226 return (ret < 0) ? ret : count; 227} 228 229static int ssif_bmc_open(struct inode *inode, struct file *file) 230{ 231 struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); 232 int ret = 0; 233 234 spin_lock_irq(&ssif_bmc->lock); 235 if (!ssif_bmc->running) 236 ssif_bmc->running = 1; 237 else 238 ret = -EBUSY; 239 spin_unlock_irq(&ssif_bmc->lock); 240 241 return ret; 242} 243 244static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait) 245{ 246 struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); 247 __poll_t mask = 0; 248 249 poll_wait(file, &ssif_bmc->wait_queue, wait); 250 251 spin_lock_irq(&ssif_bmc->lock); 252 /* The request is available, userspace application can get the request */ 253 if (ssif_bmc->request_available) 254 mask |= EPOLLIN; 255 256 spin_unlock_irq(&ssif_bmc->lock); 257 258 return mask; 259} 260 261static int ssif_bmc_release(struct inode *inode, struct file *file) 262{ 263 struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); 264 265 spin_lock_irq(&ssif_bmc->lock); 266 ssif_bmc->running = 0; 267 spin_unlock_irq(&ssif_bmc->lock); 268 269 return 0; 270} 271 272/* 273 * System calls to device interface for user apps 274 */ 275static const struct file_operations ssif_bmc_fops = { 276 .owner = THIS_MODULE, 277 .open = ssif_bmc_open, 278 .read = ssif_bmc_read, 279 .write = ssif_bmc_write, 280 .release = ssif_bmc_release, 281 .poll = ssif_bmc_poll, 282}; 283 284/* Called with ssif_bmc->lock held. */ 285static void complete_response(struct ssif_bmc_ctx *ssif_bmc) 286{ 287 /* Invalidate response in buffer to denote it having been sent. */ 288 ssif_bmc->response.len = 0; 289 ssif_bmc->response_in_progress = false; 290 ssif_bmc->nbytes_processed = 0; 291 ssif_bmc->remain_len = 0; 292 ssif_bmc->busy = false; 293 memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer)); 294 wake_up_all(&ssif_bmc->wait_queue); 295} 296 297static void response_timeout(struct timer_list *t) 298{ 299 struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer); 300 unsigned long flags; 301 302 spin_lock_irqsave(&ssif_bmc->lock, flags); 303 304 /* Do nothing if the response is in progress */ 305 if (!ssif_bmc->response_in_progress) { 306 /* Recover ssif_bmc from busy */ 307 ssif_bmc->busy = false; 308 ssif_bmc->response_timer_inited = false; 309 /* Set aborting flag */ 310 ssif_bmc->aborting = true; 311 } 312 313 spin_unlock_irqrestore(&ssif_bmc->lock, flags); 314} 315 316/* Called with ssif_bmc->lock held. */ 317static void handle_request(struct ssif_bmc_ctx *ssif_bmc) 318{ 319 /* set ssif_bmc to busy waiting for response */ 320 ssif_bmc->busy = true; 321 /* Request message is available to process */ 322 ssif_bmc->request_available = true; 323 /* Clean old response buffer */ 324 memset(&ssif_bmc->response, 0, sizeof(struct ipmi_ssif_msg)); 325 /* This is the new READ request.*/ 326 wake_up_all(&ssif_bmc->wait_queue); 327 328 /* Armed timer to recover slave from busy state in case of no response */ 329 if (!ssif_bmc->response_timer_inited) { 330 timer_setup(&ssif_bmc->response_timer, response_timeout, 0); 331 ssif_bmc->response_timer_inited = true; 332 } 333 mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT)); 334} 335 336static void calculate_response_part_pec(struct ssif_part_buffer *part) 337{ 338 u8 addr = part->address; 339 340 /* PEC - Start Read Address */ 341 part->pec = i2c_smbus_pec(0, &addr, 1); 342 /* PEC - SSIF Command */ 343 part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1); 344 /* PEC - Restart Write Address */ 345 addr = addr | 0x01; 346 part->pec = i2c_smbus_pec(part->pec, &addr, 1); 347 part->pec = i2c_smbus_pec(part->pec, &part->length, 1); 348 if (part->length) 349 part->pec = i2c_smbus_pec(part->pec, part->payload, part->length); 350} 351 352static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc) 353{ 354 struct ssif_part_buffer *part = &ssif_bmc->part_buf; 355 356 part->address = GET_8BIT_ADDR(ssif_bmc->client->addr); 357 part->length = (u8)ssif_bmc->response.len; 358 359 /* Clear the rest to 0 */ 360 memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length); 361 memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length); 362} 363 364static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc) 365{ 366 struct ssif_part_buffer *part = &ssif_bmc->part_buf; 367 u8 part_len = 0; 368 369 part->address = GET_8BIT_ADDR(ssif_bmc->client->addr); 370 switch (part->smbus_cmd) { 371 case SSIF_IPMI_MULTIPART_READ_START: 372 /* 373 * Read Start length is 32 bytes. 374 * Read Start transfer first 30 bytes of IPMI response 375 * and 2 special code 0x00, 0x01. 376 */ 377 ssif_bmc->nbytes_processed = 0; 378 ssif_bmc->block_num = 0; 379 part->length = MAX_PAYLOAD_PER_TRANSACTION; 380 part_len = MAX_IPMI_DATA_PER_START_TRANSACTION; 381 ssif_bmc->remain_len = ssif_bmc->response.len - part_len; 382 383 part->payload[0] = 0x00; /* Start Flag */ 384 part->payload[1] = 0x01; /* Start Flag */ 385 386 memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len); 387 break; 388 389 case SSIF_IPMI_MULTIPART_READ_MIDDLE: 390 /* 391 * IPMI READ Middle or READ End messages can carry up to 31 bytes 392 * IPMI data plus block number byte. 393 */ 394 if (ssif_bmc->remain_len <= MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) { 395 /* 396 * This is READ End message 397 * Return length is the remaining response data length 398 * plus block number 399 * Block number 0xFF is to indicate this is last message 400 * 401 */ 402 /* Clean the buffer */ 403 memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION); 404 part->length = ssif_bmc->remain_len + 1; 405 part_len = ssif_bmc->remain_len; 406 ssif_bmc->block_num = 0xFF; 407 part->payload[0] = ssif_bmc->block_num; 408 } else { 409 /* 410 * This is READ Middle message 411 * Response length is the maximum SMBUS transfer length 412 * Block number byte is incremented 413 * Return length is maximum SMBUS transfer length 414 */ 415 part->length = MAX_PAYLOAD_PER_TRANSACTION; 416 part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION; 417 part->payload[0] = ssif_bmc->block_num; 418 ssif_bmc->block_num++; 419 } 420 421 ssif_bmc->remain_len -= part_len; 422 memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed, 423 part_len); 424 break; 425 426 default: 427 /* Do not expect to go to this case */ 428 dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n", 429 __func__, part->smbus_cmd); 430 break; 431 } 432 433 ssif_bmc->nbytes_processed += part_len; 434} 435 436static bool supported_read_cmd(u8 cmd) 437{ 438 if (cmd == SSIF_IPMI_SINGLEPART_READ || 439 cmd == SSIF_IPMI_MULTIPART_READ_START || 440 cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE) 441 return true; 442 443 return false; 444} 445 446static bool supported_write_cmd(u8 cmd) 447{ 448 if (cmd == SSIF_IPMI_SINGLEPART_WRITE || 449 cmd == SSIF_IPMI_MULTIPART_WRITE_START || 450 cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE || 451 cmd == SSIF_IPMI_MULTIPART_WRITE_END) 452 return true; 453 454 return false; 455} 456 457/* Process the IPMI response that will be read by master */ 458static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val) 459{ 460 struct ssif_part_buffer *part = &ssif_bmc->part_buf; 461 462 /* msg_idx start from 0 */ 463 if (part->index < part->length) 464 *val = part->payload[part->index]; 465 else if (part->index == part->length && ssif_bmc->pec_support) 466 *val = part->pec; 467 else 468 *val = 0; 469 470 part->index++; 471} 472 473static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val) 474{ 475 /* 476 * The msg_idx must be 1 when first enter SSIF_REQ_RECVING state 477 * And it would never exceeded 36 bytes included the 32 bytes max payload + 478 * the address + the command + the len and the PEC. 479 */ 480 if (ssif_bmc->msg_idx < 1 || ssif_bmc->msg_idx > MAX_TRANSACTION) 481 return; 482 483 if (ssif_bmc->msg_idx == 1) { 484 ssif_bmc->part_buf.length = *val; 485 ssif_bmc->part_buf.index = 0; 486 } else { 487 ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val; 488 } 489 490 ssif_bmc->msg_idx++; 491} 492 493static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc) 494{ 495 struct ssif_part_buffer *part = &ssif_bmc->part_buf; 496 bool ret = true; 497 u8 cpec; 498 u8 addr; 499 500 if (part->index == part->length) { 501 /* PEC is not included */ 502 ssif_bmc->pec_support = false; 503 ret = true; 504 goto exit; 505 } 506 507 if (part->index != part->length + 1) { 508 ret = false; 509 goto exit; 510 } 511 512 /* PEC is included */ 513 ssif_bmc->pec_support = true; 514 part->pec = part->payload[part->length]; 515 addr = GET_8BIT_ADDR(ssif_bmc->client->addr); 516 cpec = i2c_smbus_pec(0, &addr, 1); 517 cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1); 518 cpec = i2c_smbus_pec(cpec, &part->length, 1); 519 /* 520 * As SMBus specification does not allow the length 521 * (byte count) in the Write-Block protocol to be zero. 522 * Therefore, it is illegal to have the last Middle 523 * transaction in the sequence carry 32-byte and have 524 * a length of ‘0’ in the End transaction. 525 * But some users may try to use this way and we should 526 * prevent ssif_bmc driver broken in this case. 527 */ 528 if (part->length) 529 cpec = i2c_smbus_pec(cpec, part->payload, part->length); 530 531 if (cpec != part->pec) 532 ret = false; 533 534exit: 535 return ret; 536} 537 538static void process_request_part(struct ssif_bmc_ctx *ssif_bmc) 539{ 540 struct ssif_part_buffer *part = &ssif_bmc->part_buf; 541 unsigned int len; 542 543 switch (part->smbus_cmd) { 544 case SSIF_IPMI_SINGLEPART_WRITE: 545 /* save the whole part to request*/ 546 ssif_bmc->request.len = part->length; 547 memcpy(ssif_bmc->request.payload, part->payload, part->length); 548 549 break; 550 case SSIF_IPMI_MULTIPART_WRITE_START: 551 ssif_bmc->request.len = 0; 552 553 fallthrough; 554 case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: 555 case SSIF_IPMI_MULTIPART_WRITE_END: 556 len = ssif_bmc->request.len + part->length; 557 /* Do the bound check here, not allow the request len exceed 254 bytes */ 558 if (len > IPMI_SSIF_PAYLOAD_MAX) { 559 dev_warn(&ssif_bmc->client->dev, 560 "Warn: Request exceeded 254 bytes, aborting"); 561 /* Request too long, aborting */ 562 ssif_bmc->aborting = true; 563 } else { 564 memcpy(ssif_bmc->request.payload + ssif_bmc->request.len, 565 part->payload, part->length); 566 ssif_bmc->request.len += part->length; 567 } 568 break; 569 default: 570 /* Do not expect to go to this case */ 571 dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n", 572 __func__, part->smbus_cmd); 573 break; 574 } 575} 576 577static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val) 578{ 579 /* SMBUS command can vary (single or multi-part) */ 580 ssif_bmc->part_buf.smbus_cmd = *val; 581 ssif_bmc->msg_idx = 1; 582 memset(&ssif_bmc->part_buf.payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION); 583 584 if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) { 585 /* 586 * The response maybe not come in-time, causing host SSIF driver 587 * to timeout and resend a new request. In such case check for 588 * pending response and clear it 589 */ 590 if (ssif_bmc->response_in_progress) 591 complete_response(ssif_bmc); 592 593 /* This is new request, flip aborting flag if set */ 594 if (ssif_bmc->aborting) 595 ssif_bmc->aborting = false; 596 } 597} 598 599static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val) 600{ 601 if (ssif_bmc->state == SSIF_READY || 602 ssif_bmc->state == SSIF_START || 603 ssif_bmc->state == SSIF_REQ_RECVING || 604 ssif_bmc->state == SSIF_RES_SENDING) { 605 dev_warn(&ssif_bmc->client->dev, 606 "Warn: %s unexpected READ REQUESTED in state=%s\n", 607 __func__, state_to_string(ssif_bmc->state)); 608 ssif_bmc->state = SSIF_ABORTING; 609 *val = 0; 610 return; 611 612 } else if (ssif_bmc->state == SSIF_SMBUS_CMD) { 613 if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) { 614 dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x", 615 ssif_bmc->part_buf.smbus_cmd); 616 ssif_bmc->aborting = true; 617 } 618 619 if (ssif_bmc->aborting) 620 ssif_bmc->state = SSIF_ABORTING; 621 else 622 ssif_bmc->state = SSIF_RES_SENDING; 623 } 624 625 ssif_bmc->msg_idx = 0; 626 627 /* Send 0 if there is nothing to send */ 628 if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) { 629 *val = 0; 630 return; 631 } 632 633 if (ssif_bmc->is_singlepart_read) 634 set_singlepart_response_buffer(ssif_bmc); 635 else 636 set_multipart_response_buffer(ssif_bmc); 637 638 calculate_response_part_pec(&ssif_bmc->part_buf); 639 ssif_bmc->part_buf.index = 0; 640 *val = ssif_bmc->part_buf.length; 641} 642 643static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val) 644{ 645 if (ssif_bmc->state == SSIF_READY || 646 ssif_bmc->state == SSIF_START || 647 ssif_bmc->state == SSIF_REQ_RECVING || 648 ssif_bmc->state == SSIF_SMBUS_CMD) { 649 dev_warn(&ssif_bmc->client->dev, 650 "Warn: %s unexpected READ PROCESSED in state=%s\n", 651 __func__, state_to_string(ssif_bmc->state)); 652 ssif_bmc->state = SSIF_ABORTING; 653 *val = 0; 654 return; 655 } 656 657 /* Send 0 if there is nothing to send */ 658 if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) { 659 *val = 0; 660 return; 661 } 662 663 handle_read_processed(ssif_bmc, val); 664} 665 666static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val) 667{ 668 if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) { 669 ssif_bmc->state = SSIF_START; 670 671 } else if (ssif_bmc->state == SSIF_START || 672 ssif_bmc->state == SSIF_REQ_RECVING || 673 ssif_bmc->state == SSIF_RES_SENDING) { 674 dev_warn(&ssif_bmc->client->dev, 675 "Warn: %s unexpected WRITE REQUEST in state=%s\n", 676 __func__, state_to_string(ssif_bmc->state)); 677 ssif_bmc->state = SSIF_ABORTING; 678 return; 679 } 680 681 ssif_bmc->msg_idx = 0; 682 ssif_bmc->part_buf.address = *val; 683} 684 685static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val) 686{ 687 if (ssif_bmc->state == SSIF_READY || 688 ssif_bmc->state == SSIF_RES_SENDING) { 689 dev_warn(&ssif_bmc->client->dev, 690 "Warn: %s unexpected WRITE RECEIVED in state=%s\n", 691 __func__, state_to_string(ssif_bmc->state)); 692 ssif_bmc->state = SSIF_ABORTING; 693 694 } else if (ssif_bmc->state == SSIF_START) { 695 ssif_bmc->state = SSIF_SMBUS_CMD; 696 697 } else if (ssif_bmc->state == SSIF_SMBUS_CMD) { 698 if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) { 699 dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x", 700 ssif_bmc->part_buf.smbus_cmd); 701 ssif_bmc->aborting = true; 702 } 703 704 if (ssif_bmc->aborting) 705 ssif_bmc->state = SSIF_ABORTING; 706 else 707 ssif_bmc->state = SSIF_REQ_RECVING; 708 } 709 710 /* This is response sending state */ 711 if (ssif_bmc->state == SSIF_REQ_RECVING) 712 handle_write_received(ssif_bmc, val); 713 else if (ssif_bmc->state == SSIF_SMBUS_CMD) 714 process_smbus_cmd(ssif_bmc, val); 715} 716 717static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val) 718{ 719 if (ssif_bmc->state == SSIF_READY || 720 ssif_bmc->state == SSIF_START || 721 ssif_bmc->state == SSIF_SMBUS_CMD || 722 ssif_bmc->state == SSIF_ABORTING) { 723 dev_warn(&ssif_bmc->client->dev, 724 "Warn: %s unexpected SLAVE STOP in state=%s\n", 725 __func__, state_to_string(ssif_bmc->state)); 726 ssif_bmc->state = SSIF_READY; 727 728 } else if (ssif_bmc->state == SSIF_REQ_RECVING) { 729 if (validate_request_part(ssif_bmc)) { 730 process_request_part(ssif_bmc); 731 if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE || 732 ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END) 733 handle_request(ssif_bmc); 734 ssif_bmc->state = SSIF_READY; 735 } else { 736 /* 737 * A BMC that receives an invalid request drop the data for the write 738 * transaction and any further transactions (read or write) until 739 * the next valid read or write Start transaction is received 740 */ 741 dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n"); 742 ssif_bmc->aborting = true; 743 } 744 } else if (ssif_bmc->state == SSIF_RES_SENDING) { 745 if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF) 746 /* Invalidate response buffer to denote it is sent */ 747 complete_response(ssif_bmc); 748 ssif_bmc->state = SSIF_READY; 749 } 750 751 /* Reset message index */ 752 ssif_bmc->msg_idx = 0; 753} 754 755/* 756 * Callback function to handle I2C slave events 757 */ 758static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val) 759{ 760 unsigned long flags; 761 struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client); 762 int ret = 0; 763 764 spin_lock_irqsave(&ssif_bmc->lock, flags); 765 766 switch (event) { 767 case I2C_SLAVE_READ_REQUESTED: 768 on_read_requested_event(ssif_bmc, val); 769 break; 770 771 case I2C_SLAVE_WRITE_REQUESTED: 772 on_write_requested_event(ssif_bmc, val); 773 break; 774 775 case I2C_SLAVE_READ_PROCESSED: 776 on_read_processed_event(ssif_bmc, val); 777 break; 778 779 case I2C_SLAVE_WRITE_RECEIVED: 780 on_write_received_event(ssif_bmc, val); 781 break; 782 783 case I2C_SLAVE_STOP: 784 on_stop_event(ssif_bmc, val); 785 break; 786 787 default: 788 dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n"); 789 break; 790 } 791 792 if (!ssif_bmc->aborting && ssif_bmc->busy) 793 ret = -EBUSY; 794 795 spin_unlock_irqrestore(&ssif_bmc->lock, flags); 796 797 return ret; 798} 799 800static int ssif_bmc_probe(struct i2c_client *client) 801{ 802 struct ssif_bmc_ctx *ssif_bmc; 803 int ret; 804 805 ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL); 806 if (!ssif_bmc) 807 return -ENOMEM; 808 809 spin_lock_init(&ssif_bmc->lock); 810 811 init_waitqueue_head(&ssif_bmc->wait_queue); 812 ssif_bmc->request_available = false; 813 ssif_bmc->response_in_progress = false; 814 ssif_bmc->busy = false; 815 ssif_bmc->response_timer_inited = false; 816 817 /* Register misc device interface */ 818 ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR; 819 ssif_bmc->miscdev.name = DEVICE_NAME; 820 ssif_bmc->miscdev.fops = &ssif_bmc_fops; 821 ssif_bmc->miscdev.parent = &client->dev; 822 ret = misc_register(&ssif_bmc->miscdev); 823 if (ret) 824 return ret; 825 826 ssif_bmc->client = client; 827 ssif_bmc->client->flags |= I2C_CLIENT_SLAVE; 828 829 /* Register I2C slave */ 830 i2c_set_clientdata(client, ssif_bmc); 831 ret = i2c_slave_register(client, ssif_bmc_cb); 832 if (ret) 833 misc_deregister(&ssif_bmc->miscdev); 834 835 return ret; 836} 837 838static void ssif_bmc_remove(struct i2c_client *client) 839{ 840 struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client); 841 842 i2c_slave_unregister(client); 843 misc_deregister(&ssif_bmc->miscdev); 844} 845 846static const struct of_device_id ssif_bmc_match[] = { 847 { .compatible = "ssif-bmc" }, 848 { }, 849}; 850MODULE_DEVICE_TABLE(of, ssif_bmc_match); 851 852static const struct i2c_device_id ssif_bmc_id[] = { 853 { DEVICE_NAME, 0 }, 854 { }, 855}; 856MODULE_DEVICE_TABLE(i2c, ssif_bmc_id); 857 858static struct i2c_driver ssif_bmc_driver = { 859 .driver = { 860 .name = DEVICE_NAME, 861 .of_match_table = ssif_bmc_match, 862 }, 863 .probe = ssif_bmc_probe, 864 .remove = ssif_bmc_remove, 865 .id_table = ssif_bmc_id, 866}; 867 868module_i2c_driver(ssif_bmc_driver); 869 870MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>"); 871MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>"); 872MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface."); 873MODULE_LICENSE("GPL"); 874