1 /* 2 * Copyright (c) 2015-2016, IBM Corporation. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 */ 9 10 #include <linux/atomic.h> 11 #include <linux/bt-bmc.h> 12 #include <linux/errno.h> 13 #include <linux/interrupt.h> 14 #include <linux/io.h> 15 #include <linux/miscdevice.h> 16 #include <linux/module.h> 17 #include <linux/platform_device.h> 18 #include <linux/poll.h> 19 #include <linux/sched.h> 20 #include <linux/timer.h> 21 22 /* 23 * This is a BMC device used to communicate to the host 24 */ 25 #define DEVICE_NAME "ipmi-bt-host" 26 27 #define BT_IO_BASE 0xe4 28 #define BT_IRQ 10 29 30 #define BT_CR0 0x0 31 #define BT_CR0_IO_BASE 16 32 #define BT_CR0_IRQ 12 33 #define BT_CR0_EN_CLR_SLV_RDP 0x8 34 #define BT_CR0_EN_CLR_SLV_WRP 0x4 35 #define BT_CR0_ENABLE_IBT 0x1 36 #define BT_CR1 0x4 37 #define BT_CR1_IRQ_H2B 0x01 38 #define BT_CR1_IRQ_HBUSY 0x40 39 #define BT_CR2 0x8 40 #define BT_CR2_IRQ_H2B 0x01 41 #define BT_CR2_IRQ_HBUSY 0x40 42 #define BT_CR3 0xc 43 #define BT_CTRL 0x10 44 #define BT_CTRL_B_BUSY 0x80 45 #define BT_CTRL_H_BUSY 0x40 46 #define BT_CTRL_OEM0 0x20 47 #define BT_CTRL_SMS_ATN 0x10 48 #define BT_CTRL_B2H_ATN 0x08 49 #define BT_CTRL_H2B_ATN 0x04 50 #define BT_CTRL_CLR_RD_PTR 0x02 51 #define BT_CTRL_CLR_WR_PTR 0x01 52 #define BT_BMC2HOST 0x14 53 #define BT_INTMASK 0x18 54 #define BT_INTMASK_B2H_IRQEN 0x01 55 #define BT_INTMASK_B2H_IRQ 0x02 56 #define BT_INTMASK_BMC_HWRST 0x80 57 58 #define BT_BMC_BUFFER_SIZE 256 59 60 struct bt_bmc { 61 struct device dev; 62 struct miscdevice miscdev; 63 void __iomem *base; 64 int irq; 65 wait_queue_head_t queue; 66 struct timer_list poll_timer; 67 struct mutex mutex; 68 }; 69 70 static atomic_t open_count = ATOMIC_INIT(0); 71 72 static u8 bt_inb(struct bt_bmc *bt_bmc, int reg) 73 { 74 return ioread8(bt_bmc->base + reg); 75 } 76 77 static void bt_outb(struct bt_bmc *bt_bmc, u8 data, int reg) 78 { 79 iowrite8(data, bt_bmc->base + reg); 80 } 81 82 static void clr_rd_ptr(struct bt_bmc *bt_bmc) 83 { 84 bt_outb(bt_bmc, BT_CTRL_CLR_RD_PTR, BT_CTRL); 85 } 86 87 static void clr_wr_ptr(struct bt_bmc *bt_bmc) 88 { 89 bt_outb(bt_bmc, BT_CTRL_CLR_WR_PTR, BT_CTRL); 90 } 91 92 static void clr_h2b_atn(struct bt_bmc *bt_bmc) 93 { 94 bt_outb(bt_bmc, BT_CTRL_H2B_ATN, BT_CTRL); 95 } 96 97 static void set_b_busy(struct bt_bmc *bt_bmc) 98 { 99 if (!(bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_B_BUSY)) 100 bt_outb(bt_bmc, BT_CTRL_B_BUSY, BT_CTRL); 101 } 102 103 static void clr_b_busy(struct bt_bmc *bt_bmc) 104 { 105 if (bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_B_BUSY) 106 bt_outb(bt_bmc, BT_CTRL_B_BUSY, BT_CTRL); 107 } 108 109 static void set_b2h_atn(struct bt_bmc *bt_bmc) 110 { 111 bt_outb(bt_bmc, BT_CTRL_B2H_ATN, BT_CTRL); 112 } 113 114 static u8 bt_read(struct bt_bmc *bt_bmc) 115 { 116 return bt_inb(bt_bmc, BT_BMC2HOST); 117 } 118 119 static ssize_t bt_readn(struct bt_bmc *bt_bmc, u8 *buf, size_t n) 120 { 121 int i; 122 123 for (i = 0; i < n; i++) 124 buf[i] = bt_read(bt_bmc); 125 return n; 126 } 127 128 static void bt_write(struct bt_bmc *bt_bmc, u8 c) 129 { 130 bt_outb(bt_bmc, c, BT_BMC2HOST); 131 } 132 133 static ssize_t bt_writen(struct bt_bmc *bt_bmc, u8 *buf, size_t n) 134 { 135 int i; 136 137 for (i = 0; i < n; i++) 138 bt_write(bt_bmc, buf[i]); 139 return n; 140 } 141 142 static void set_sms_atn(struct bt_bmc *bt_bmc) 143 { 144 bt_outb(bt_bmc, BT_CTRL_SMS_ATN, BT_CTRL); 145 } 146 147 static struct bt_bmc *file_bt_bmc(struct file *file) 148 { 149 return container_of(file->private_data, struct bt_bmc, miscdev); 150 } 151 152 static int bt_bmc_open(struct inode *inode, struct file *file) 153 { 154 struct bt_bmc *bt_bmc = file_bt_bmc(file); 155 156 if (atomic_inc_return(&open_count) == 1) { 157 clr_b_busy(bt_bmc); 158 return 0; 159 } 160 161 atomic_dec(&open_count); 162 return -EBUSY; 163 } 164 165 /* 166 * The BT (Block Transfer) interface means that entire messages are 167 * buffered by the host before a notification is sent to the BMC that 168 * there is data to be read. The first byte is the length and the 169 * message data follows. The read operation just tries to capture the 170 * whole before returning it to userspace. 171 * 172 * BT Message format : 173 * 174 * Byte 1 Byte 2 Byte 3 Byte 4 Byte 5:N 175 * Length NetFn/LUN Seq Cmd Data 176 * 177 */ 178 static ssize_t bt_bmc_read(struct file *file, char __user *buf, 179 size_t count, loff_t *ppos) 180 { 181 struct bt_bmc *bt_bmc = file_bt_bmc(file); 182 u8 len; 183 int len_byte = 1; 184 u8 kbuffer[BT_BMC_BUFFER_SIZE]; 185 ssize_t ret = 0; 186 ssize_t nread; 187 188 if (!access_ok(VERIFY_WRITE, buf, count)) 189 return -EFAULT; 190 191 WARN_ON(*ppos); 192 193 if (wait_event_interruptible(bt_bmc->queue, 194 bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_H2B_ATN)) 195 return -ERESTARTSYS; 196 197 mutex_lock(&bt_bmc->mutex); 198 199 if (unlikely(!(bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_H2B_ATN))) { 200 ret = -EIO; 201 goto out_unlock; 202 } 203 204 set_b_busy(bt_bmc); 205 clr_h2b_atn(bt_bmc); 206 clr_rd_ptr(bt_bmc); 207 208 /* 209 * The BT frames start with the message length, which does not 210 * include the length byte. 211 */ 212 kbuffer[0] = bt_read(bt_bmc); 213 len = kbuffer[0]; 214 215 /* We pass the length back to userspace as well */ 216 if (len + 1 > count) 217 len = count - 1; 218 219 while (len) { 220 nread = min_t(ssize_t, len, sizeof(kbuffer) - len_byte); 221 222 bt_readn(bt_bmc, kbuffer + len_byte, nread); 223 224 if (copy_to_user(buf, kbuffer, nread + len_byte)) { 225 ret = -EFAULT; 226 break; 227 } 228 len -= nread; 229 buf += nread + len_byte; 230 ret += nread + len_byte; 231 len_byte = 0; 232 } 233 234 clr_b_busy(bt_bmc); 235 236 out_unlock: 237 mutex_unlock(&bt_bmc->mutex); 238 return ret; 239 } 240 241 /* 242 * BT Message response format : 243 * 244 * Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6:N 245 * Length NetFn/LUN Seq Cmd Code Data 246 */ 247 static ssize_t bt_bmc_write(struct file *file, const char __user *buf, 248 size_t count, loff_t *ppos) 249 { 250 struct bt_bmc *bt_bmc = file_bt_bmc(file); 251 u8 kbuffer[BT_BMC_BUFFER_SIZE]; 252 ssize_t ret = 0; 253 ssize_t nwritten; 254 255 /* 256 * send a minimum response size 257 */ 258 if (count < 5) 259 return -EINVAL; 260 261 if (!access_ok(VERIFY_READ, buf, count)) 262 return -EFAULT; 263 264 WARN_ON(*ppos); 265 266 /* 267 * There's no interrupt for clearing bmc busy so we have to 268 * poll 269 */ 270 if (wait_event_interruptible(bt_bmc->queue, 271 !(bt_inb(bt_bmc, BT_CTRL) & 272 (BT_CTRL_H_BUSY | BT_CTRL_B2H_ATN)))) 273 return -ERESTARTSYS; 274 275 mutex_lock(&bt_bmc->mutex); 276 277 if (unlikely(bt_inb(bt_bmc, BT_CTRL) & 278 (BT_CTRL_H_BUSY | BT_CTRL_B2H_ATN))) { 279 ret = -EIO; 280 goto out_unlock; 281 } 282 283 clr_wr_ptr(bt_bmc); 284 285 while (count) { 286 nwritten = min_t(ssize_t, count, sizeof(kbuffer)); 287 if (copy_from_user(&kbuffer, buf, nwritten)) { 288 ret = -EFAULT; 289 break; 290 } 291 292 bt_writen(bt_bmc, kbuffer, nwritten); 293 294 count -= nwritten; 295 buf += nwritten; 296 ret += nwritten; 297 } 298 299 set_b2h_atn(bt_bmc); 300 301 out_unlock: 302 mutex_unlock(&bt_bmc->mutex); 303 return ret; 304 } 305 306 static long bt_bmc_ioctl(struct file *file, unsigned int cmd, 307 unsigned long param) 308 { 309 struct bt_bmc *bt_bmc = file_bt_bmc(file); 310 311 switch (cmd) { 312 case BT_BMC_IOCTL_SMS_ATN: 313 set_sms_atn(bt_bmc); 314 return 0; 315 } 316 return -EINVAL; 317 } 318 319 static int bt_bmc_release(struct inode *inode, struct file *file) 320 { 321 struct bt_bmc *bt_bmc = file_bt_bmc(file); 322 323 atomic_dec(&open_count); 324 set_b_busy(bt_bmc); 325 return 0; 326 } 327 328 static unsigned int bt_bmc_poll(struct file *file, poll_table *wait) 329 { 330 struct bt_bmc *bt_bmc = file_bt_bmc(file); 331 unsigned int mask = 0; 332 u8 ctrl; 333 334 poll_wait(file, &bt_bmc->queue, wait); 335 336 ctrl = bt_inb(bt_bmc, BT_CTRL); 337 338 if (ctrl & BT_CTRL_H2B_ATN) 339 mask |= POLLIN; 340 341 if (!(ctrl & (BT_CTRL_H_BUSY | BT_CTRL_B2H_ATN))) 342 mask |= POLLOUT; 343 344 return mask; 345 } 346 347 static const struct file_operations bt_bmc_fops = { 348 .owner = THIS_MODULE, 349 .open = bt_bmc_open, 350 .read = bt_bmc_read, 351 .write = bt_bmc_write, 352 .release = bt_bmc_release, 353 .poll = bt_bmc_poll, 354 .unlocked_ioctl = bt_bmc_ioctl, 355 }; 356 357 static void poll_timer(unsigned long data) 358 { 359 struct bt_bmc *bt_bmc = (void *)data; 360 361 bt_bmc->poll_timer.expires += msecs_to_jiffies(500); 362 wake_up(&bt_bmc->queue); 363 add_timer(&bt_bmc->poll_timer); 364 } 365 366 static irqreturn_t bt_bmc_irq(int irq, void *arg) 367 { 368 struct bt_bmc *bt_bmc = arg; 369 u32 reg; 370 371 reg = ioread32(bt_bmc->base + BT_CR2); 372 reg &= BT_CR2_IRQ_H2B | BT_CR2_IRQ_HBUSY; 373 if (!reg) 374 return IRQ_NONE; 375 376 /* ack pending IRQs */ 377 iowrite32(reg, bt_bmc->base + BT_CR2); 378 379 wake_up(&bt_bmc->queue); 380 return IRQ_HANDLED; 381 } 382 383 static int bt_bmc_config_irq(struct bt_bmc *bt_bmc, 384 struct platform_device *pdev) 385 { 386 struct device *dev = &pdev->dev; 387 u32 reg; 388 int rc; 389 390 bt_bmc->irq = platform_get_irq(pdev, 0); 391 if (!bt_bmc->irq) 392 return -ENODEV; 393 394 rc = devm_request_irq(dev, bt_bmc->irq, bt_bmc_irq, IRQF_SHARED, 395 DEVICE_NAME, bt_bmc); 396 if (rc < 0) { 397 dev_warn(dev, "Unable to request IRQ %d\n", bt_bmc->irq); 398 bt_bmc->irq = 0; 399 return rc; 400 } 401 402 /* 403 * Configure IRQs on the bmc clearing the H2B and HBUSY bits; 404 * H2B will be asserted when the bmc has data for us; HBUSY 405 * will be cleared (along with B2H) when we can write the next 406 * message to the BT buffer 407 */ 408 reg = ioread32(bt_bmc->base + BT_CR1); 409 reg |= BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY; 410 iowrite32(reg, bt_bmc->base + BT_CR1); 411 412 return 0; 413 } 414 415 static int bt_bmc_probe(struct platform_device *pdev) 416 { 417 struct bt_bmc *bt_bmc; 418 struct device *dev; 419 struct resource *res; 420 int rc; 421 422 if (!pdev || !pdev->dev.of_node) 423 return -ENODEV; 424 425 dev = &pdev->dev; 426 dev_info(dev, "Found bt bmc device\n"); 427 428 bt_bmc = devm_kzalloc(dev, sizeof(*bt_bmc), GFP_KERNEL); 429 if (!bt_bmc) 430 return -ENOMEM; 431 432 dev_set_drvdata(&pdev->dev, bt_bmc); 433 434 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 435 bt_bmc->base = devm_ioremap_resource(&pdev->dev, res); 436 if (IS_ERR(bt_bmc->base)) 437 return PTR_ERR(bt_bmc->base); 438 439 mutex_init(&bt_bmc->mutex); 440 init_waitqueue_head(&bt_bmc->queue); 441 442 bt_bmc->miscdev.minor = MISC_DYNAMIC_MINOR, 443 bt_bmc->miscdev.name = DEVICE_NAME, 444 bt_bmc->miscdev.fops = &bt_bmc_fops, 445 bt_bmc->miscdev.parent = dev; 446 rc = misc_register(&bt_bmc->miscdev); 447 if (rc) { 448 dev_err(dev, "Unable to register misc device\n"); 449 return rc; 450 } 451 452 bt_bmc_config_irq(bt_bmc, pdev); 453 454 if (bt_bmc->irq) { 455 dev_info(dev, "Using IRQ %d\n", bt_bmc->irq); 456 } else { 457 dev_info(dev, "No IRQ; using timer\n"); 458 setup_timer(&bt_bmc->poll_timer, poll_timer, 459 (unsigned long)bt_bmc); 460 bt_bmc->poll_timer.expires = jiffies + msecs_to_jiffies(10); 461 add_timer(&bt_bmc->poll_timer); 462 } 463 464 iowrite32((BT_IO_BASE << BT_CR0_IO_BASE) | 465 (BT_IRQ << BT_CR0_IRQ) | 466 BT_CR0_EN_CLR_SLV_RDP | 467 BT_CR0_EN_CLR_SLV_WRP | 468 BT_CR0_ENABLE_IBT, 469 bt_bmc->base + BT_CR0); 470 471 clr_b_busy(bt_bmc); 472 473 return 0; 474 } 475 476 static int bt_bmc_remove(struct platform_device *pdev) 477 { 478 struct bt_bmc *bt_bmc = dev_get_drvdata(&pdev->dev); 479 480 misc_deregister(&bt_bmc->miscdev); 481 if (!bt_bmc->irq) 482 del_timer_sync(&bt_bmc->poll_timer); 483 return 0; 484 } 485 486 static const struct of_device_id bt_bmc_match[] = { 487 { .compatible = "aspeed,ast2400-bt-bmc" }, 488 { }, 489 }; 490 491 static struct platform_driver bt_bmc_driver = { 492 .driver = { 493 .name = DEVICE_NAME, 494 .of_match_table = bt_bmc_match, 495 }, 496 .probe = bt_bmc_probe, 497 .remove = bt_bmc_remove, 498 }; 499 500 module_platform_driver(bt_bmc_driver); 501 502 MODULE_DEVICE_TABLE(of, bt_bmc_match); 503 MODULE_LICENSE("GPL"); 504 MODULE_AUTHOR("Alistair Popple <alistair@popple.id.au>"); 505 MODULE_DESCRIPTION("Linux device interface to the BT interface"); 506