1 /* 2 * Copyright (c) 2016 Mellanox Technologies. All rights reserved. 3 * Copyright (c) 2016 Michael Shych <michaels@mellanox.com> 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the names of the copyright holders nor the names of its 14 * contributors may be used to endorse or promote products derived from 15 * this software without specific prior written permission. 16 * 17 * Alternatively, this software may be distributed under the terms of the 18 * GNU General Public License ("GPL") version 2 as published by the Free 19 * Software Foundation. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 25 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <linux/delay.h> 35 #include <linux/i2c.h> 36 #include <linux/init.h> 37 #include <linux/io.h> 38 #include <linux/kernel.h> 39 #include <linux/module.h> 40 #include <linux/platform_device.h> 41 42 /* General defines */ 43 #define MLXPLAT_CPLD_LPC_I2C_BASE_ADDR 0x2000 44 #define MLXCPLD_I2C_DEVICE_NAME "i2c_mlxcpld" 45 #define MLXCPLD_I2C_VALID_FLAG (I2C_M_RECV_LEN | I2C_M_RD) 46 #define MLXCPLD_I2C_BUS_NUM 1 47 #define MLXCPLD_I2C_DATA_REG_SZ 36 48 #define MLXCPLD_I2C_DATA_SZ_BIT BIT(5) 49 #define MLXCPLD_I2C_DATA_SZ_MASK GENMASK(6, 5) 50 #define MLXCPLD_I2C_SMBUS_BLK_BIT BIT(7) 51 #define MLXCPLD_I2C_MAX_ADDR_LEN 4 52 #define MLXCPLD_I2C_RETR_NUM 2 53 #define MLXCPLD_I2C_XFER_TO 500000 /* usec */ 54 #define MLXCPLD_I2C_POLL_TIME 2000 /* usec */ 55 56 /* LPC I2C registers */ 57 #define MLXCPLD_LPCI2C_CPBLTY_REG 0x0 58 #define MLXCPLD_LPCI2C_CTRL_REG 0x1 59 #define MLXCPLD_LPCI2C_HALF_CYC_REG 0x4 60 #define MLXCPLD_LPCI2C_I2C_HOLD_REG 0x5 61 #define MLXCPLD_LPCI2C_CMD_REG 0x6 62 #define MLXCPLD_LPCI2C_NUM_DAT_REG 0x7 63 #define MLXCPLD_LPCI2C_NUM_ADDR_REG 0x8 64 #define MLXCPLD_LPCI2C_STATUS_REG 0x9 65 #define MLXCPLD_LPCI2C_DATA_REG 0xa 66 67 /* LPC I2C masks and parametres */ 68 #define MLXCPLD_LPCI2C_RST_SEL_MASK 0x1 69 #define MLXCPLD_LPCI2C_TRANS_END 0x1 70 #define MLXCPLD_LPCI2C_STATUS_NACK 0x10 71 #define MLXCPLD_LPCI2C_NO_IND 0 72 #define MLXCPLD_LPCI2C_ACK_IND 1 73 #define MLXCPLD_LPCI2C_NACK_IND 2 74 75 struct mlxcpld_i2c_curr_xfer { 76 u8 cmd; 77 u8 addr_width; 78 u8 data_len; 79 u8 msg_num; 80 struct i2c_msg *msg; 81 }; 82 83 struct mlxcpld_i2c_priv { 84 struct i2c_adapter adap; 85 u32 base_addr; 86 struct mutex lock; 87 struct mlxcpld_i2c_curr_xfer xfer; 88 struct device *dev; 89 bool smbus_block; 90 }; 91 92 static void mlxcpld_i2c_lpc_write_buf(u8 *data, u8 len, u32 addr) 93 { 94 int i; 95 96 for (i = 0; i < len - len % 4; i += 4) 97 outl(*(u32 *)(data + i), addr + i); 98 for (; i < len; ++i) 99 outb(*(data + i), addr + i); 100 } 101 102 static void mlxcpld_i2c_lpc_read_buf(u8 *data, u8 len, u32 addr) 103 { 104 int i; 105 106 for (i = 0; i < len - len % 4; i += 4) 107 *(u32 *)(data + i) = inl(addr + i); 108 for (; i < len; ++i) 109 *(data + i) = inb(addr + i); 110 } 111 112 static void mlxcpld_i2c_read_comm(struct mlxcpld_i2c_priv *priv, u8 offs, 113 u8 *data, u8 datalen) 114 { 115 u32 addr = priv->base_addr + offs; 116 117 switch (datalen) { 118 case 1: 119 *(data) = inb(addr); 120 break; 121 case 2: 122 *((u16 *)data) = inw(addr); 123 break; 124 case 3: 125 *((u16 *)data) = inw(addr); 126 *(data + 2) = inb(addr + 2); 127 break; 128 case 4: 129 *((u32 *)data) = inl(addr); 130 break; 131 default: 132 mlxcpld_i2c_lpc_read_buf(data, datalen, addr); 133 break; 134 } 135 } 136 137 static void mlxcpld_i2c_write_comm(struct mlxcpld_i2c_priv *priv, u8 offs, 138 u8 *data, u8 datalen) 139 { 140 u32 addr = priv->base_addr + offs; 141 142 switch (datalen) { 143 case 1: 144 outb(*(data), addr); 145 break; 146 case 2: 147 outw(*((u16 *)data), addr); 148 break; 149 case 3: 150 outw(*((u16 *)data), addr); 151 outb(*(data + 2), addr + 2); 152 break; 153 case 4: 154 outl(*((u32 *)data), addr); 155 break; 156 default: 157 mlxcpld_i2c_lpc_write_buf(data, datalen, addr); 158 break; 159 } 160 } 161 162 /* 163 * Check validity of received i2c messages parameters. 164 * Returns 0 if OK, other - in case of invalid parameters. 165 */ 166 static int mlxcpld_i2c_check_msg_params(struct mlxcpld_i2c_priv *priv, 167 struct i2c_msg *msgs, int num) 168 { 169 int i; 170 171 if (!num) { 172 dev_err(priv->dev, "Incorrect 0 num of messages\n"); 173 return -EINVAL; 174 } 175 176 if (unlikely(msgs[0].addr > 0x7f)) { 177 dev_err(priv->dev, "Invalid address 0x%03x\n", 178 msgs[0].addr); 179 return -EINVAL; 180 } 181 182 for (i = 0; i < num; ++i) { 183 if (unlikely(!msgs[i].buf)) { 184 dev_err(priv->dev, "Invalid buf in msg[%d]\n", 185 i); 186 return -EINVAL; 187 } 188 if (unlikely(msgs[0].addr != msgs[i].addr)) { 189 dev_err(priv->dev, "Invalid addr in msg[%d]\n", 190 i); 191 return -EINVAL; 192 } 193 } 194 195 return 0; 196 } 197 198 /* 199 * Check if transfer is completed and status of operation. 200 * Returns 0 - transfer completed (both ACK or NACK), 201 * negative - transfer isn't finished. 202 */ 203 static int mlxcpld_i2c_check_status(struct mlxcpld_i2c_priv *priv, int *status) 204 { 205 u8 val; 206 207 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_STATUS_REG, &val, 1); 208 209 if (val & MLXCPLD_LPCI2C_TRANS_END) { 210 if (val & MLXCPLD_LPCI2C_STATUS_NACK) 211 /* 212 * The slave is unable to accept the data. No such 213 * slave, command not understood, or unable to accept 214 * any more data. 215 */ 216 *status = MLXCPLD_LPCI2C_NACK_IND; 217 else 218 *status = MLXCPLD_LPCI2C_ACK_IND; 219 return 0; 220 } 221 *status = MLXCPLD_LPCI2C_NO_IND; 222 223 return -EIO; 224 } 225 226 static void mlxcpld_i2c_set_transf_data(struct mlxcpld_i2c_priv *priv, 227 struct i2c_msg *msgs, int num, 228 u8 comm_len) 229 { 230 priv->xfer.msg = msgs; 231 priv->xfer.msg_num = num; 232 233 /* 234 * All upper layers currently are never use transfer with more than 235 * 2 messages. Actually, it's also not so relevant in Mellanox systems 236 * because of HW limitation. Max size of transfer is not more than 32 237 * or 68 bytes in the current x86 LPCI2C bridge. 238 */ 239 priv->xfer.cmd = msgs[num - 1].flags & I2C_M_RD; 240 241 if (priv->xfer.cmd == I2C_M_RD && comm_len != msgs[0].len) { 242 priv->xfer.addr_width = msgs[0].len; 243 priv->xfer.data_len = comm_len - priv->xfer.addr_width; 244 } else { 245 priv->xfer.addr_width = 0; 246 priv->xfer.data_len = comm_len; 247 } 248 } 249 250 /* Reset CPLD LPCI2C block */ 251 static void mlxcpld_i2c_reset(struct mlxcpld_i2c_priv *priv) 252 { 253 u8 val; 254 255 mutex_lock(&priv->lock); 256 257 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_CTRL_REG, &val, 1); 258 val &= ~MLXCPLD_LPCI2C_RST_SEL_MASK; 259 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_CTRL_REG, &val, 1); 260 261 mutex_unlock(&priv->lock); 262 } 263 264 /* Make sure the CPLD is ready to start transmitting. */ 265 static int mlxcpld_i2c_check_busy(struct mlxcpld_i2c_priv *priv) 266 { 267 u8 val; 268 269 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_STATUS_REG, &val, 1); 270 271 if (val & MLXCPLD_LPCI2C_TRANS_END) 272 return 0; 273 274 return -EIO; 275 } 276 277 static int mlxcpld_i2c_wait_for_free(struct mlxcpld_i2c_priv *priv) 278 { 279 int timeout = 0; 280 281 do { 282 if (!mlxcpld_i2c_check_busy(priv)) 283 break; 284 usleep_range(MLXCPLD_I2C_POLL_TIME / 2, MLXCPLD_I2C_POLL_TIME); 285 timeout += MLXCPLD_I2C_POLL_TIME; 286 } while (timeout <= MLXCPLD_I2C_XFER_TO); 287 288 if (timeout > MLXCPLD_I2C_XFER_TO) 289 return -ETIMEDOUT; 290 291 return 0; 292 } 293 294 /* 295 * Wait for master transfer to complete. 296 * It puts current process to sleep until we get interrupt or timeout expires. 297 * Returns the number of transferred or read bytes or error (<0). 298 */ 299 static int mlxcpld_i2c_wait_for_tc(struct mlxcpld_i2c_priv *priv) 300 { 301 int status, i, timeout = 0; 302 u8 datalen, val; 303 304 do { 305 usleep_range(MLXCPLD_I2C_POLL_TIME / 2, MLXCPLD_I2C_POLL_TIME); 306 if (!mlxcpld_i2c_check_status(priv, &status)) 307 break; 308 timeout += MLXCPLD_I2C_POLL_TIME; 309 } while (status == 0 && timeout < MLXCPLD_I2C_XFER_TO); 310 311 switch (status) { 312 case MLXCPLD_LPCI2C_NO_IND: 313 return -ETIMEDOUT; 314 315 case MLXCPLD_LPCI2C_ACK_IND: 316 if (priv->xfer.cmd != I2C_M_RD) 317 return (priv->xfer.addr_width + priv->xfer.data_len); 318 319 if (priv->xfer.msg_num == 1) 320 i = 0; 321 else 322 i = 1; 323 324 if (!priv->xfer.msg[i].buf) 325 return -EINVAL; 326 327 /* 328 * Actual read data len will be always the same as 329 * requested len. 0xff (line pull-up) will be returned 330 * if slave has no data to return. Thus don't read 331 * MLXCPLD_LPCI2C_NUM_DAT_REG reg from CPLD. Only in case of 332 * SMBus block read transaction data len can be different, 333 * check this case. 334 */ 335 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_NUM_ADDR_REG, &val, 336 1); 337 if (priv->smbus_block && (val & MLXCPLD_I2C_SMBUS_BLK_BIT)) { 338 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_NUM_DAT_REG, 339 &datalen, 1); 340 if (unlikely(datalen > I2C_SMBUS_BLOCK_MAX)) { 341 dev_err(priv->dev, "Incorrect smbus block read message len\n"); 342 return -EPROTO; 343 } 344 } else { 345 datalen = priv->xfer.data_len; 346 } 347 348 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_DATA_REG, 349 priv->xfer.msg[i].buf, datalen); 350 351 return datalen; 352 353 case MLXCPLD_LPCI2C_NACK_IND: 354 return -ENXIO; 355 356 default: 357 return -EINVAL; 358 } 359 } 360 361 static void mlxcpld_i2c_xfer_msg(struct mlxcpld_i2c_priv *priv) 362 { 363 int i, len = 0; 364 u8 cmd, val; 365 366 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_NUM_DAT_REG, 367 &priv->xfer.data_len, 1); 368 369 val = priv->xfer.addr_width; 370 /* Notify HW about SMBus block read transaction */ 371 if (priv->smbus_block && priv->xfer.msg_num >= 2 && 372 priv->xfer.msg[1].len == 1 && 373 (priv->xfer.msg[1].flags & I2C_M_RECV_LEN) && 374 (priv->xfer.msg[1].flags & I2C_M_RD)) 375 val |= MLXCPLD_I2C_SMBUS_BLK_BIT; 376 377 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_NUM_ADDR_REG, &val, 1); 378 379 for (i = 0; i < priv->xfer.msg_num; i++) { 380 if ((priv->xfer.msg[i].flags & I2C_M_RD) != I2C_M_RD) { 381 /* Don't write to CPLD buffer in read transaction */ 382 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_DATA_REG + 383 len, priv->xfer.msg[i].buf, 384 priv->xfer.msg[i].len); 385 len += priv->xfer.msg[i].len; 386 } 387 } 388 389 /* 390 * Set target slave address with command for master transfer. 391 * It should be latest executed function before CPLD transaction. 392 */ 393 cmd = (priv->xfer.msg[0].addr << 1) | priv->xfer.cmd; 394 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_CMD_REG, &cmd, 1); 395 } 396 397 /* 398 * Generic lpc-i2c transfer. 399 * Returns the number of processed messages or error (<0). 400 */ 401 static int mlxcpld_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 402 int num) 403 { 404 struct mlxcpld_i2c_priv *priv = i2c_get_adapdata(adap); 405 u8 comm_len = 0; 406 int i, err; 407 408 err = mlxcpld_i2c_check_msg_params(priv, msgs, num); 409 if (err) { 410 dev_err(priv->dev, "Incorrect message\n"); 411 return err; 412 } 413 414 for (i = 0; i < num; ++i) 415 comm_len += msgs[i].len; 416 417 /* Check bus state */ 418 if (mlxcpld_i2c_wait_for_free(priv)) { 419 dev_err(priv->dev, "LPCI2C bridge is busy\n"); 420 421 /* 422 * Usually it means something serious has happened. 423 * We can not have unfinished previous transfer 424 * so it doesn't make any sense to try to stop it. 425 * Probably we were not able to recover from the 426 * previous error. 427 * The only reasonable thing - is soft reset. 428 */ 429 mlxcpld_i2c_reset(priv); 430 if (mlxcpld_i2c_check_busy(priv)) { 431 dev_err(priv->dev, "LPCI2C bridge is busy after reset\n"); 432 return -EIO; 433 } 434 } 435 436 mlxcpld_i2c_set_transf_data(priv, msgs, num, comm_len); 437 438 mutex_lock(&priv->lock); 439 440 /* Do real transfer. Can't fail */ 441 mlxcpld_i2c_xfer_msg(priv); 442 443 /* Wait for transaction complete */ 444 err = mlxcpld_i2c_wait_for_tc(priv); 445 446 mutex_unlock(&priv->lock); 447 448 return err < 0 ? err : num; 449 } 450 451 static u32 mlxcpld_i2c_func(struct i2c_adapter *adap) 452 { 453 struct mlxcpld_i2c_priv *priv = i2c_get_adapdata(adap); 454 455 if (priv->smbus_block) 456 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | 457 I2C_FUNC_SMBUS_I2C_BLOCK | I2C_FUNC_SMBUS_BLOCK_DATA; 458 else 459 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | 460 I2C_FUNC_SMBUS_I2C_BLOCK; 461 } 462 463 static const struct i2c_algorithm mlxcpld_i2c_algo = { 464 .master_xfer = mlxcpld_i2c_xfer, 465 .functionality = mlxcpld_i2c_func 466 }; 467 468 static const struct i2c_adapter_quirks mlxcpld_i2c_quirks = { 469 .flags = I2C_AQ_COMB_WRITE_THEN_READ, 470 .max_read_len = MLXCPLD_I2C_DATA_REG_SZ - MLXCPLD_I2C_MAX_ADDR_LEN, 471 .max_write_len = MLXCPLD_I2C_DATA_REG_SZ, 472 .max_comb_1st_msg_len = 4, 473 }; 474 475 static const struct i2c_adapter_quirks mlxcpld_i2c_quirks_ext = { 476 .flags = I2C_AQ_COMB_WRITE_THEN_READ, 477 .max_read_len = MLXCPLD_I2C_DATA_REG_SZ * 2 - MLXCPLD_I2C_MAX_ADDR_LEN, 478 .max_write_len = MLXCPLD_I2C_DATA_REG_SZ * 2, 479 .max_comb_1st_msg_len = 4, 480 }; 481 482 static struct i2c_adapter mlxcpld_i2c_adapter = { 483 .owner = THIS_MODULE, 484 .name = "i2c-mlxcpld", 485 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD, 486 .algo = &mlxcpld_i2c_algo, 487 .quirks = &mlxcpld_i2c_quirks, 488 .retries = MLXCPLD_I2C_RETR_NUM, 489 .nr = MLXCPLD_I2C_BUS_NUM, 490 }; 491 492 static int mlxcpld_i2c_probe(struct platform_device *pdev) 493 { 494 struct mlxcpld_i2c_priv *priv; 495 int err; 496 u8 val; 497 498 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 499 if (!priv) 500 return -ENOMEM; 501 502 mutex_init(&priv->lock); 503 platform_set_drvdata(pdev, priv); 504 505 priv->dev = &pdev->dev; 506 priv->base_addr = MLXPLAT_CPLD_LPC_I2C_BASE_ADDR; 507 508 /* Register with i2c layer */ 509 mlxcpld_i2c_adapter.timeout = usecs_to_jiffies(MLXCPLD_I2C_XFER_TO); 510 /* Read capability register */ 511 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_CPBLTY_REG, &val, 1); 512 /* Check support for extended transaction length */ 513 if ((val & MLXCPLD_I2C_DATA_SZ_MASK) == MLXCPLD_I2C_DATA_SZ_BIT) 514 mlxcpld_i2c_adapter.quirks = &mlxcpld_i2c_quirks_ext; 515 /* Check support for smbus block transaction */ 516 if (val & MLXCPLD_I2C_SMBUS_BLK_BIT) 517 priv->smbus_block = true; 518 if (pdev->id >= -1) 519 mlxcpld_i2c_adapter.nr = pdev->id; 520 priv->adap = mlxcpld_i2c_adapter; 521 priv->adap.dev.parent = &pdev->dev; 522 i2c_set_adapdata(&priv->adap, priv); 523 524 err = i2c_add_numbered_adapter(&priv->adap); 525 if (err) 526 mutex_destroy(&priv->lock); 527 528 return err; 529 } 530 531 static int mlxcpld_i2c_remove(struct platform_device *pdev) 532 { 533 struct mlxcpld_i2c_priv *priv = platform_get_drvdata(pdev); 534 535 i2c_del_adapter(&priv->adap); 536 mutex_destroy(&priv->lock); 537 538 return 0; 539 } 540 541 static struct platform_driver mlxcpld_i2c_driver = { 542 .probe = mlxcpld_i2c_probe, 543 .remove = mlxcpld_i2c_remove, 544 .driver = { 545 .name = MLXCPLD_I2C_DEVICE_NAME, 546 }, 547 }; 548 549 module_platform_driver(mlxcpld_i2c_driver); 550 551 MODULE_AUTHOR("Michael Shych <michaels@mellanox.com>"); 552 MODULE_DESCRIPTION("Mellanox I2C-CPLD controller driver"); 553 MODULE_LICENSE("Dual BSD/GPL"); 554 MODULE_ALIAS("platform:i2c-mlxcpld"); 555