1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2015-2018, Intel Corporation. 4 */ 5 6 #define pr_fmt(fmt) "kcs-bmc: " fmt 7 8 #include <linux/errno.h> 9 #include <linux/io.h> 10 #include <linux/ipmi_bmc.h> 11 #include <linux/module.h> 12 #include <linux/platform_device.h> 13 #include <linux/poll.h> 14 #include <linux/sched.h> 15 #include <linux/slab.h> 16 17 #include "kcs_bmc.h" 18 19 #define KCS_MSG_BUFSIZ 1000 20 21 #define KCS_ZERO_DATA 0 22 23 24 /* IPMI 2.0 - Table 9-1, KCS Interface Status Register Bits */ 25 #define KCS_STATUS_STATE(state) (state << 6) 26 #define KCS_STATUS_STATE_MASK GENMASK(7, 6) 27 #define KCS_STATUS_CMD_DAT BIT(3) 28 #define KCS_STATUS_SMS_ATN BIT(2) 29 #define KCS_STATUS_IBF BIT(1) 30 #define KCS_STATUS_OBF BIT(0) 31 32 /* IPMI 2.0 - Table 9-2, KCS Interface State Bits */ 33 enum kcs_states { 34 IDLE_STATE = 0, 35 READ_STATE = 1, 36 WRITE_STATE = 2, 37 ERROR_STATE = 3, 38 }; 39 40 /* IPMI 2.0 - Table 9-3, KCS Interface Control Codes */ 41 #define KCS_CMD_GET_STATUS_ABORT 0x60 42 #define KCS_CMD_WRITE_START 0x61 43 #define KCS_CMD_WRITE_END 0x62 44 #define KCS_CMD_READ_BYTE 0x68 45 46 static inline u8 read_data(struct kcs_bmc *kcs_bmc) 47 { 48 return kcs_bmc->io_inputb(kcs_bmc, kcs_bmc->ioreg.idr); 49 } 50 51 static inline void write_data(struct kcs_bmc *kcs_bmc, u8 data) 52 { 53 kcs_bmc->io_outputb(kcs_bmc, kcs_bmc->ioreg.odr, data); 54 } 55 56 static inline u8 read_status(struct kcs_bmc *kcs_bmc) 57 { 58 return kcs_bmc->io_inputb(kcs_bmc, kcs_bmc->ioreg.str); 59 } 60 61 static inline void write_status(struct kcs_bmc *kcs_bmc, u8 data) 62 { 63 kcs_bmc->io_outputb(kcs_bmc, kcs_bmc->ioreg.str, data); 64 } 65 66 static void update_status_bits(struct kcs_bmc *kcs_bmc, u8 mask, u8 val) 67 { 68 u8 tmp = read_status(kcs_bmc); 69 70 tmp &= ~mask; 71 tmp |= val & mask; 72 73 write_status(kcs_bmc, tmp); 74 } 75 76 static inline void set_state(struct kcs_bmc *kcs_bmc, u8 state) 77 { 78 update_status_bits(kcs_bmc, KCS_STATUS_STATE_MASK, 79 KCS_STATUS_STATE(state)); 80 } 81 82 static void kcs_force_abort(struct kcs_bmc *kcs_bmc) 83 { 84 set_state(kcs_bmc, ERROR_STATE); 85 read_data(kcs_bmc); 86 write_data(kcs_bmc, KCS_ZERO_DATA); 87 88 kcs_bmc->phase = KCS_PHASE_ERROR; 89 kcs_bmc->data_in_avail = false; 90 kcs_bmc->data_in_idx = 0; 91 } 92 93 static void kcs_bmc_handle_data(struct kcs_bmc *kcs_bmc) 94 { 95 u8 data; 96 97 switch (kcs_bmc->phase) { 98 case KCS_PHASE_WRITE_START: 99 kcs_bmc->phase = KCS_PHASE_WRITE_DATA; 100 /* fall through */ 101 102 case KCS_PHASE_WRITE_DATA: 103 if (kcs_bmc->data_in_idx < KCS_MSG_BUFSIZ) { 104 set_state(kcs_bmc, WRITE_STATE); 105 write_data(kcs_bmc, KCS_ZERO_DATA); 106 kcs_bmc->data_in[kcs_bmc->data_in_idx++] = 107 read_data(kcs_bmc); 108 } else { 109 kcs_force_abort(kcs_bmc); 110 kcs_bmc->error = KCS_LENGTH_ERROR; 111 } 112 break; 113 114 case KCS_PHASE_WRITE_END_CMD: 115 if (kcs_bmc->data_in_idx < KCS_MSG_BUFSIZ) { 116 set_state(kcs_bmc, READ_STATE); 117 kcs_bmc->data_in[kcs_bmc->data_in_idx++] = 118 read_data(kcs_bmc); 119 kcs_bmc->phase = KCS_PHASE_WRITE_DONE; 120 kcs_bmc->data_in_avail = true; 121 wake_up_interruptible(&kcs_bmc->queue); 122 } else { 123 kcs_force_abort(kcs_bmc); 124 kcs_bmc->error = KCS_LENGTH_ERROR; 125 } 126 break; 127 128 case KCS_PHASE_READ: 129 if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len) 130 set_state(kcs_bmc, IDLE_STATE); 131 132 data = read_data(kcs_bmc); 133 if (data != KCS_CMD_READ_BYTE) { 134 set_state(kcs_bmc, ERROR_STATE); 135 write_data(kcs_bmc, KCS_ZERO_DATA); 136 break; 137 } 138 139 if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len) { 140 write_data(kcs_bmc, KCS_ZERO_DATA); 141 kcs_bmc->phase = KCS_PHASE_IDLE; 142 break; 143 } 144 145 write_data(kcs_bmc, 146 kcs_bmc->data_out[kcs_bmc->data_out_idx++]); 147 break; 148 149 case KCS_PHASE_ABORT_ERROR1: 150 set_state(kcs_bmc, READ_STATE); 151 read_data(kcs_bmc); 152 write_data(kcs_bmc, kcs_bmc->error); 153 kcs_bmc->phase = KCS_PHASE_ABORT_ERROR2; 154 break; 155 156 case KCS_PHASE_ABORT_ERROR2: 157 set_state(kcs_bmc, IDLE_STATE); 158 read_data(kcs_bmc); 159 write_data(kcs_bmc, KCS_ZERO_DATA); 160 kcs_bmc->phase = KCS_PHASE_IDLE; 161 break; 162 163 default: 164 kcs_force_abort(kcs_bmc); 165 break; 166 } 167 } 168 169 static void kcs_bmc_handle_cmd(struct kcs_bmc *kcs_bmc) 170 { 171 u8 cmd; 172 173 set_state(kcs_bmc, WRITE_STATE); 174 write_data(kcs_bmc, KCS_ZERO_DATA); 175 176 cmd = read_data(kcs_bmc); 177 switch (cmd) { 178 case KCS_CMD_WRITE_START: 179 kcs_bmc->phase = KCS_PHASE_WRITE_START; 180 kcs_bmc->error = KCS_NO_ERROR; 181 kcs_bmc->data_in_avail = false; 182 kcs_bmc->data_in_idx = 0; 183 break; 184 185 case KCS_CMD_WRITE_END: 186 if (kcs_bmc->phase != KCS_PHASE_WRITE_DATA) { 187 kcs_force_abort(kcs_bmc); 188 break; 189 } 190 191 kcs_bmc->phase = KCS_PHASE_WRITE_END_CMD; 192 break; 193 194 case KCS_CMD_GET_STATUS_ABORT: 195 if (kcs_bmc->error == KCS_NO_ERROR) 196 kcs_bmc->error = KCS_ABORTED_BY_COMMAND; 197 198 kcs_bmc->phase = KCS_PHASE_ABORT_ERROR1; 199 kcs_bmc->data_in_avail = false; 200 kcs_bmc->data_in_idx = 0; 201 break; 202 203 default: 204 kcs_force_abort(kcs_bmc); 205 kcs_bmc->error = KCS_ILLEGAL_CONTROL_CODE; 206 break; 207 } 208 } 209 210 int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc) 211 { 212 unsigned long flags; 213 int ret = -ENODATA; 214 u8 status; 215 216 spin_lock_irqsave(&kcs_bmc->lock, flags); 217 218 status = read_status(kcs_bmc); 219 if (status & KCS_STATUS_IBF) { 220 if (!kcs_bmc->running) 221 kcs_force_abort(kcs_bmc); 222 else if (status & KCS_STATUS_CMD_DAT) 223 kcs_bmc_handle_cmd(kcs_bmc); 224 else 225 kcs_bmc_handle_data(kcs_bmc); 226 227 ret = 0; 228 } 229 230 spin_unlock_irqrestore(&kcs_bmc->lock, flags); 231 232 return ret; 233 } 234 EXPORT_SYMBOL(kcs_bmc_handle_event); 235 236 static inline struct kcs_bmc *to_kcs_bmc(struct file *filp) 237 { 238 return container_of(filp->private_data, struct kcs_bmc, miscdev); 239 } 240 241 static int kcs_bmc_open(struct inode *inode, struct file *filp) 242 { 243 struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); 244 int ret = 0; 245 246 spin_lock_irq(&kcs_bmc->lock); 247 if (!kcs_bmc->running) 248 kcs_bmc->running = 1; 249 else 250 ret = -EBUSY; 251 spin_unlock_irq(&kcs_bmc->lock); 252 253 return ret; 254 } 255 256 static __poll_t kcs_bmc_poll(struct file *filp, poll_table *wait) 257 { 258 struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); 259 __poll_t mask = 0; 260 261 poll_wait(filp, &kcs_bmc->queue, wait); 262 263 spin_lock_irq(&kcs_bmc->lock); 264 if (kcs_bmc->data_in_avail) 265 mask |= EPOLLIN; 266 spin_unlock_irq(&kcs_bmc->lock); 267 268 return mask; 269 } 270 271 static ssize_t kcs_bmc_read(struct file *filp, char __user *buf, 272 size_t count, loff_t *ppos) 273 { 274 struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); 275 bool data_avail; 276 size_t data_len; 277 ssize_t ret; 278 279 if (!(filp->f_flags & O_NONBLOCK)) 280 wait_event_interruptible(kcs_bmc->queue, 281 kcs_bmc->data_in_avail); 282 283 mutex_lock(&kcs_bmc->mutex); 284 285 spin_lock_irq(&kcs_bmc->lock); 286 data_avail = kcs_bmc->data_in_avail; 287 if (data_avail) { 288 data_len = kcs_bmc->data_in_idx; 289 memcpy(kcs_bmc->kbuffer, kcs_bmc->data_in, data_len); 290 } 291 spin_unlock_irq(&kcs_bmc->lock); 292 293 if (!data_avail) { 294 ret = -EAGAIN; 295 goto out_unlock; 296 } 297 298 if (count < data_len) { 299 pr_err("channel=%u with too large data : %zu\n", 300 kcs_bmc->channel, data_len); 301 302 spin_lock_irq(&kcs_bmc->lock); 303 kcs_force_abort(kcs_bmc); 304 spin_unlock_irq(&kcs_bmc->lock); 305 306 ret = -EOVERFLOW; 307 goto out_unlock; 308 } 309 310 if (copy_to_user(buf, kcs_bmc->kbuffer, data_len)) { 311 ret = -EFAULT; 312 goto out_unlock; 313 } 314 315 ret = data_len; 316 317 spin_lock_irq(&kcs_bmc->lock); 318 if (kcs_bmc->phase == KCS_PHASE_WRITE_DONE) { 319 kcs_bmc->phase = KCS_PHASE_WAIT_READ; 320 kcs_bmc->data_in_avail = false; 321 kcs_bmc->data_in_idx = 0; 322 } else { 323 ret = -EAGAIN; 324 } 325 spin_unlock_irq(&kcs_bmc->lock); 326 327 out_unlock: 328 mutex_unlock(&kcs_bmc->mutex); 329 330 return ret; 331 } 332 333 static ssize_t kcs_bmc_write(struct file *filp, const char __user *buf, 334 size_t count, loff_t *ppos) 335 { 336 struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); 337 ssize_t ret; 338 339 /* a minimum response size '3' : netfn + cmd + ccode */ 340 if (count < 3 || count > KCS_MSG_BUFSIZ) 341 return -EINVAL; 342 343 mutex_lock(&kcs_bmc->mutex); 344 345 if (copy_from_user(kcs_bmc->kbuffer, buf, count)) { 346 ret = -EFAULT; 347 goto out_unlock; 348 } 349 350 spin_lock_irq(&kcs_bmc->lock); 351 if (kcs_bmc->phase == KCS_PHASE_WAIT_READ) { 352 kcs_bmc->phase = KCS_PHASE_READ; 353 kcs_bmc->data_out_idx = 1; 354 kcs_bmc->data_out_len = count; 355 memcpy(kcs_bmc->data_out, kcs_bmc->kbuffer, count); 356 write_data(kcs_bmc, kcs_bmc->data_out[0]); 357 ret = count; 358 } else { 359 ret = -EINVAL; 360 } 361 spin_unlock_irq(&kcs_bmc->lock); 362 363 out_unlock: 364 mutex_unlock(&kcs_bmc->mutex); 365 366 return ret; 367 } 368 369 static long kcs_bmc_ioctl(struct file *filp, unsigned int cmd, 370 unsigned long arg) 371 { 372 struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); 373 long ret = 0; 374 375 spin_lock_irq(&kcs_bmc->lock); 376 377 switch (cmd) { 378 case IPMI_BMC_IOCTL_SET_SMS_ATN: 379 update_status_bits(kcs_bmc, KCS_STATUS_SMS_ATN, 380 KCS_STATUS_SMS_ATN); 381 break; 382 383 case IPMI_BMC_IOCTL_CLEAR_SMS_ATN: 384 update_status_bits(kcs_bmc, KCS_STATUS_SMS_ATN, 385 0); 386 break; 387 388 case IPMI_BMC_IOCTL_FORCE_ABORT: 389 kcs_force_abort(kcs_bmc); 390 break; 391 392 default: 393 ret = -EINVAL; 394 break; 395 } 396 397 spin_unlock_irq(&kcs_bmc->lock); 398 399 return ret; 400 } 401 402 static int kcs_bmc_release(struct inode *inode, struct file *filp) 403 { 404 struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); 405 406 spin_lock_irq(&kcs_bmc->lock); 407 kcs_bmc->running = 0; 408 kcs_force_abort(kcs_bmc); 409 spin_unlock_irq(&kcs_bmc->lock); 410 411 return 0; 412 } 413 414 static const struct file_operations kcs_bmc_fops = { 415 .owner = THIS_MODULE, 416 .open = kcs_bmc_open, 417 .read = kcs_bmc_read, 418 .write = kcs_bmc_write, 419 .release = kcs_bmc_release, 420 .poll = kcs_bmc_poll, 421 .unlocked_ioctl = kcs_bmc_ioctl, 422 }; 423 424 struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv, u32 channel) 425 { 426 struct kcs_bmc *kcs_bmc; 427 428 kcs_bmc = devm_kzalloc(dev, sizeof(*kcs_bmc) + sizeof_priv, GFP_KERNEL); 429 if (!kcs_bmc) 430 return NULL; 431 432 dev_set_name(dev, "ipmi-kcs%u", channel); 433 434 spin_lock_init(&kcs_bmc->lock); 435 kcs_bmc->channel = channel; 436 437 mutex_init(&kcs_bmc->mutex); 438 init_waitqueue_head(&kcs_bmc->queue); 439 440 kcs_bmc->data_in = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL); 441 kcs_bmc->data_out = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL); 442 kcs_bmc->kbuffer = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL); 443 if (!kcs_bmc->data_in || !kcs_bmc->data_out || !kcs_bmc->kbuffer) 444 return NULL; 445 446 kcs_bmc->miscdev.minor = MISC_DYNAMIC_MINOR; 447 kcs_bmc->miscdev.name = dev_name(dev); 448 kcs_bmc->miscdev.fops = &kcs_bmc_fops; 449 450 return kcs_bmc; 451 } 452 EXPORT_SYMBOL(kcs_bmc_alloc); 453 454 MODULE_LICENSE("GPL v2"); 455 MODULE_AUTHOR("Haiyue Wang <haiyue.wang@linux.intel.com>"); 456 MODULE_DESCRIPTION("KCS BMC to handle the IPMI request from system software"); 457