drivers/gpu/drm/i915/intel_i2c.c

   1 /*
   2  * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
   3  * Copyright © 2006-2008,2010 Intel Corporation
   4  *   Jesse Barnes <jesse.barnes@intel.com>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the next
  14  * paragraph) shall be included in all copies or substantial portions of the
  15  * Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  23  * DEALINGS IN THE SOFTWARE.
  24  *
  25  * Authors:
  26  *      Eric Anholt <eric@anholt.net>
  27  *      Chris Wilson <chris@chris-wilson.co.uk>
  28  */
  29 #include <linux/i2c.h>
  30 #include <linux/i2c-algo-bit.h>
  31 #include <linux/export.h>
  32 #include <drm/drmP.h>
  33 #include <drm/drm_hdcp.h>
  34 #include "intel_drv.h"
  35 #include <drm/i915_drm.h>
  36 #include "i915_drv.h"
  37
  38 struct gmbus_pin {
  39         const char *name;
  40         i915_reg_t reg;
  41 };
  42
  43 /* Map gmbus pin pairs to names and registers. */
  44 static const struct gmbus_pin gmbus_pins[] = {
  45         [GMBUS_PIN_SSC] = { "ssc", GPIOB },
  46         [GMBUS_PIN_VGADDC] = { "vga", GPIOA },
  47         [GMBUS_PIN_PANEL] = { "panel", GPIOC },
  48         [GMBUS_PIN_DPC] = { "dpc", GPIOD },
  49         [GMBUS_PIN_DPB] = { "dpb", GPIOE },
  50         [GMBUS_PIN_DPD] = { "dpd", GPIOF },
  51 };
  52
  53 static const struct gmbus_pin gmbus_pins_bdw[] = {
  54         [GMBUS_PIN_VGADDC] = { "vga", GPIOA },
  55         [GMBUS_PIN_DPC] = { "dpc", GPIOD },
  56         [GMBUS_PIN_DPB] = { "dpb", GPIOE },
  57         [GMBUS_PIN_DPD] = { "dpd", GPIOF },
  58 };
  59
  60 static const struct gmbus_pin gmbus_pins_skl[] = {
  61         [GMBUS_PIN_DPC] = { "dpc", GPIOD },
  62         [GMBUS_PIN_DPB] = { "dpb", GPIOE },
  63         [GMBUS_PIN_DPD] = { "dpd", GPIOF },
  64 };
  65
  66 static const struct gmbus_pin gmbus_pins_bxt[] = {
  67         [GMBUS_PIN_1_BXT] = { "dpb", GPIOB },
  68         [GMBUS_PIN_2_BXT] = { "dpc", GPIOC },
  69         [GMBUS_PIN_3_BXT] = { "misc", GPIOD },
  70 };
  71
  72 static const struct gmbus_pin gmbus_pins_cnp[] = {
  73         [GMBUS_PIN_1_BXT] = { "dpb", GPIOB },
  74         [GMBUS_PIN_2_BXT] = { "dpc", GPIOC },
  75         [GMBUS_PIN_3_BXT] = { "misc", GPIOD },
  76         [GMBUS_PIN_4_CNP] = { "dpd", GPIOE },
  77 };
  78
  79 static const struct gmbus_pin gmbus_pins_icp[] = {
  80         [GMBUS_PIN_1_BXT] = { "dpa", GPIOB },
  81         [GMBUS_PIN_2_BXT] = { "dpb", GPIOC },
  82         [GMBUS_PIN_9_TC1_ICP] = { "tc1", GPIOJ },
  83         [GMBUS_PIN_10_TC2_ICP] = { "tc2", GPIOK },
  84         [GMBUS_PIN_11_TC3_ICP] = { "tc3", GPIOL },
  85         [GMBUS_PIN_12_TC4_ICP] = { "tc4", GPIOM },
  86 };
  87
  88 /* pin is expected to be valid */
  89 static const struct gmbus_pin *get_gmbus_pin(struct drm_i915_private *dev_priv,
  90                                              unsigned int pin)
  91 {
  92         if (HAS_PCH_ICP(dev_priv))
  93                 return &gmbus_pins_icp[pin];
  94         else if (HAS_PCH_CNP(dev_priv))
  95                 return &gmbus_pins_cnp[pin];
  96         else if (IS_GEN9_LP(dev_priv))
  97                 return &gmbus_pins_bxt[pin];
  98         else if (IS_GEN9_BC(dev_priv))
  99                 return &gmbus_pins_skl[pin];
 100         else if (IS_BROADWELL(dev_priv))
 101                 return &gmbus_pins_bdw[pin];
 102         else
 103                 return &gmbus_pins[pin];
 104 }
 105
 106 bool intel_gmbus_is_valid_pin(struct drm_i915_private *dev_priv,
 107                               unsigned int pin)
 108 {
 109         unsigned int size;
 110
 111         if (HAS_PCH_ICP(dev_priv))
 112                 size = ARRAY_SIZE(gmbus_pins_icp);
 113         else if (HAS_PCH_CNP(dev_priv))
 114                 size = ARRAY_SIZE(gmbus_pins_cnp);
 115         else if (IS_GEN9_LP(dev_priv))
 116                 size = ARRAY_SIZE(gmbus_pins_bxt);
 117         else if (IS_GEN9_BC(dev_priv))
 118                 size = ARRAY_SIZE(gmbus_pins_skl);
 119         else if (IS_BROADWELL(dev_priv))
 120                 size = ARRAY_SIZE(gmbus_pins_bdw);
 121         else
 122                 size = ARRAY_SIZE(gmbus_pins);
 123
 124         return pin < size &&
 125                 i915_mmio_reg_valid(get_gmbus_pin(dev_priv, pin)->reg);
 126 }
 127
 128 /* Intel GPIO access functions */
 129
 130 #define I2C_RISEFALL_TIME 10
 131
 132 static inline struct intel_gmbus *
 133 to_intel_gmbus(struct i2c_adapter *i2c)
 134 {
 135         return container_of(i2c, struct intel_gmbus, adapter);
 136 }
 137
 138 void
 139 intel_i2c_reset(struct drm_i915_private *dev_priv)
 140 {
 141         I915_WRITE(GMBUS0, 0);
 142         I915_WRITE(GMBUS4, 0);
 143 }
 144
 145 static void pnv_gmbus_clock_gating(struct drm_i915_private *dev_priv,
 146                                    bool enable)
 147 {
 148         u32 val;
 149
 150         /* When using bit bashing for I2C, this bit needs to be set to 1 */
 151         val = I915_READ(DSPCLK_GATE_D);
 152         if (!enable)
 153                 val |= PNV_GMBUSUNIT_CLOCK_GATE_DISABLE;
 154         else
 155                 val &= ~PNV_GMBUSUNIT_CLOCK_GATE_DISABLE;
 156         I915_WRITE(DSPCLK_GATE_D, val);
 157 }
 158
 159 static void pch_gmbus_clock_gating(struct drm_i915_private *dev_priv,
 160                                    bool enable)
 161 {
 162         u32 val;
 163
 164         val = I915_READ(SOUTH_DSPCLK_GATE_D);
 165         if (!enable)
 166                 val |= PCH_GMBUSUNIT_CLOCK_GATE_DISABLE;
 167         else
 168                 val &= ~PCH_GMBUSUNIT_CLOCK_GATE_DISABLE;
 169         I915_WRITE(SOUTH_DSPCLK_GATE_D, val);
 170 }
 171
 172 static void bxt_gmbus_clock_gating(struct drm_i915_private *dev_priv,
 173                                    bool enable)
 174 {
 175         u32 val;
 176
 177         val = I915_READ(GEN9_CLKGATE_DIS_4);
 178         if (!enable)
 179                 val |= BXT_GMBUS_GATING_DIS;
 180         else
 181                 val &= ~BXT_GMBUS_GATING_DIS;
 182         I915_WRITE(GEN9_CLKGATE_DIS_4, val);
 183 }
 184
 185 static u32 get_reserved(struct intel_gmbus *bus)
 186 {
 187         struct drm_i915_private *dev_priv = bus->dev_priv;
 188         u32 reserved = 0;
 189
 190         /* On most chips, these bits must be preserved in software. */
 191         if (!IS_I830(dev_priv) && !IS_I845G(dev_priv))
 192                 reserved = I915_READ_NOTRACE(bus->gpio_reg) &
 193                                              (GPIO_DATA_PULLUP_DISABLE |
 194                                               GPIO_CLOCK_PULLUP_DISABLE);
 195
 196         return reserved;
 197 }
 198
 199 static int get_clock(void *data)
 200 {
 201         struct intel_gmbus *bus = data;
 202         struct drm_i915_private *dev_priv = bus->dev_priv;
 203         u32 reserved = get_reserved(bus);
 204         I915_WRITE_NOTRACE(bus->gpio_reg, reserved | GPIO_CLOCK_DIR_MASK);
 205         I915_WRITE_NOTRACE(bus->gpio_reg, reserved);
 206         return (I915_READ_NOTRACE(bus->gpio_reg) & GPIO_CLOCK_VAL_IN) != 0;
 207 }
 208
 209 static int get_data(void *data)
 210 {
 211         struct intel_gmbus *bus = data;
 212         struct drm_i915_private *dev_priv = bus->dev_priv;
 213         u32 reserved = get_reserved(bus);
 214         I915_WRITE_NOTRACE(bus->gpio_reg, reserved | GPIO_DATA_DIR_MASK);
 215         I915_WRITE_NOTRACE(bus->gpio_reg, reserved);
 216         return (I915_READ_NOTRACE(bus->gpio_reg) & GPIO_DATA_VAL_IN) != 0;
 217 }
 218
 219 static void set_clock(void *data, int state_high)
 220 {
 221         struct intel_gmbus *bus = data;
 222         struct drm_i915_private *dev_priv = bus->dev_priv;
 223         u32 reserved = get_reserved(bus);
 224         u32 clock_bits;
 225
 226         if (state_high)
 227                 clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
 228         else
 229                 clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
 230                         GPIO_CLOCK_VAL_MASK;
 231
 232         I915_WRITE_NOTRACE(bus->gpio_reg, reserved | clock_bits);
 233         POSTING_READ(bus->gpio_reg);
 234 }
 235
 236 static void set_data(void *data, int state_high)
 237 {
 238         struct intel_gmbus *bus = data;
 239         struct drm_i915_private *dev_priv = bus->dev_priv;
 240         u32 reserved = get_reserved(bus);
 241         u32 data_bits;
 242
 243         if (state_high)
 244                 data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
 245         else
 246                 data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
 247                         GPIO_DATA_VAL_MASK;
 248
 249         I915_WRITE_NOTRACE(bus->gpio_reg, reserved | data_bits);
 250         POSTING_READ(bus->gpio_reg);
 251 }
 252
 253 static int
 254 intel_gpio_pre_xfer(struct i2c_adapter *adapter)
 255 {
 256         struct intel_gmbus *bus = container_of(adapter,
 257                                                struct intel_gmbus,
 258                                                adapter);
 259         struct drm_i915_private *dev_priv = bus->dev_priv;
 260
 261         intel_i2c_reset(dev_priv);
 262
 263         if (IS_PINEVIEW(dev_priv))
 264                 pnv_gmbus_clock_gating(dev_priv, false);
 265
 266         set_data(bus, 1);
 267         set_clock(bus, 1);
 268         udelay(I2C_RISEFALL_TIME);
 269         return 0;
 270 }
 271
 272 static void
 273 intel_gpio_post_xfer(struct i2c_adapter *adapter)
 274 {
 275         struct intel_gmbus *bus = container_of(adapter,
 276                                                struct intel_gmbus,
 277                                                adapter);
 278         struct drm_i915_private *dev_priv = bus->dev_priv;
 279
 280         set_data(bus, 1);
 281         set_clock(bus, 1);
 282
 283         if (IS_PINEVIEW(dev_priv))
 284                 pnv_gmbus_clock_gating(dev_priv, true);
 285 }
 286
 287 static void
 288 intel_gpio_setup(struct intel_gmbus *bus, unsigned int pin)
 289 {
 290         struct drm_i915_private *dev_priv = bus->dev_priv;
 291         struct i2c_algo_bit_data *algo;
 292
 293         algo = &bus->bit_algo;
 294
 295         bus->gpio_reg = _MMIO(dev_priv->gpio_mmio_base +
 296                               i915_mmio_reg_offset(get_gmbus_pin(dev_priv, pin)->reg));
 297         bus->adapter.algo_data = algo;
 298         algo->setsda = set_data;
 299         algo->setscl = set_clock;
 300         algo->getsda = get_data;
 301         algo->getscl = get_clock;
 302         algo->pre_xfer = intel_gpio_pre_xfer;
 303         algo->post_xfer = intel_gpio_post_xfer;
 304         algo->udelay = I2C_RISEFALL_TIME;
 305         algo->timeout = usecs_to_jiffies(2200);
 306         algo->data = bus;
 307 }
 308
 309 static int gmbus_wait(struct drm_i915_private *dev_priv, u32 status, u32 irq_en)
 310 {
 311         DEFINE_WAIT(wait);
 312         u32 gmbus2;
 313         int ret;
 314
 315         /* Important: The hw handles only the first bit, so set only one! Since
 316          * we also need to check for NAKs besides the hw ready/idle signal, we
 317          * need to wake up periodically and check that ourselves.
 318          */
 319         if (!HAS_GMBUS_IRQ(dev_priv))
 320                 irq_en = 0;
 321
 322         add_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
 323         I915_WRITE_FW(GMBUS4, irq_en);
 324
 325         status |= GMBUS_SATOER;
 326         ret = wait_for_us((gmbus2 = I915_READ_FW(GMBUS2)) & status, 2);
 327         if (ret)
 328                 ret = wait_for((gmbus2 = I915_READ_FW(GMBUS2)) & status, 50);
 329
 330         I915_WRITE_FW(GMBUS4, 0);
 331         remove_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
 332
 333         if (gmbus2 & GMBUS_SATOER)
 334                 return -ENXIO;
 335
 336         return ret;
 337 }
 338
 339 static int
 340 gmbus_wait_idle(struct drm_i915_private *dev_priv)
 341 {
 342         DEFINE_WAIT(wait);
 343         u32 irq_enable;
 344         int ret;
 345
 346         /* Important: The hw handles only the first bit, so set only one! */
 347         irq_enable = 0;
 348         if (HAS_GMBUS_IRQ(dev_priv))
 349                 irq_enable = GMBUS_IDLE_EN;
 350
 351         add_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
 352         I915_WRITE_FW(GMBUS4, irq_enable);
 353
 354         ret = intel_wait_for_register_fw(dev_priv,
 355                                          GMBUS2, GMBUS_ACTIVE, 0,
 356                                          10);
 357
 358         I915_WRITE_FW(GMBUS4, 0);
 359         remove_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
 360
 361         return ret;
 362 }
 363
 364 static inline
 365 unsigned int gmbus_max_xfer_size(struct drm_i915_private *dev_priv)
 366 {
 367         return INTEL_GEN(dev_priv) >= 9 ? GEN9_GMBUS_BYTE_COUNT_MAX :
 368                GMBUS_BYTE_COUNT_MAX;
 369 }
 370
 371 static int
 372 gmbus_xfer_read_chunk(struct drm_i915_private *dev_priv,
 373                       unsigned short addr, u8 *buf, unsigned int len,
 374                       u32 gmbus0_reg, u32 gmbus1_index)
 375 {
 376         unsigned int size = len;
 377         bool burst_read = len > gmbus_max_xfer_size(dev_priv);
 378         bool extra_byte_added = false;
 379
 380         if (burst_read) {
 381                 /*
 382                  * As per HW Spec, for 512Bytes need to read extra Byte and
 383                  * Ignore the extra byte read.
 384                  */
 385                 if (len == 512) {
 386                         extra_byte_added = true;
 387                         len++;
 388                 }
 389                 size = len % 256 + 256;
 390                 I915_WRITE_FW(GMBUS0, gmbus0_reg | GMBUS_BYTE_CNT_OVERRIDE);
 391         }
 392
 393         I915_WRITE_FW(GMBUS1,
 394                       gmbus1_index |
 395                       GMBUS_CYCLE_WAIT |
 396                       (size << GMBUS_BYTE_COUNT_SHIFT) |
 397                       (addr << GMBUS_SLAVE_ADDR_SHIFT) |
 398                       GMBUS_SLAVE_READ | GMBUS_SW_RDY);
 399         while (len) {
 400                 int ret;
 401                 u32 val, loop = 0;
 402
 403                 ret = gmbus_wait(dev_priv, GMBUS_HW_RDY, GMBUS_HW_RDY_EN);
 404                 if (ret)
 405                         return ret;
 406
 407                 val = I915_READ_FW(GMBUS3);
 408                 do {
 409                         if (extra_byte_added && len == 1)
 410                                 break;
 411
 412                         *buf++ = val & 0xff;
 413                         val >>= 8;
 414                 } while (--len && ++loop < 4);
 415
 416                 if (burst_read && len == size - 4)
 417                         /* Reset the override bit */
 418                         I915_WRITE_FW(GMBUS0, gmbus0_reg);
 419         }
 420
 421         return 0;
 422 }
 423
 424 /*
 425  * HW spec says that 512Bytes in Burst read need special treatment.
 426  * But it doesn't talk about other multiple of 256Bytes. And couldn't locate
 427  * an I2C slave, which supports such a lengthy burst read too for experiments.
 428  *
 429  * So until things get clarified on HW support, to avoid the burst read length
 430  * in fold of 256Bytes except 512, max burst read length is fixed at 767Bytes.
 431  */
 432 #define INTEL_GMBUS_BURST_READ_MAX_LEN          767U
 433
 434 static int
 435 gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
 436                 u32 gmbus0_reg, u32 gmbus1_index)
 437 {
 438         u8 *buf = msg->buf;
 439         unsigned int rx_size = msg->len;
 440         unsigned int len;
 441         int ret;
 442
 443         do {
 444                 if (HAS_GMBUS_BURST_READ(dev_priv))
 445                         len = min(rx_size, INTEL_GMBUS_BURST_READ_MAX_LEN);
 446                 else
 447                         len = min(rx_size, gmbus_max_xfer_size(dev_priv));
 448
 449                 ret = gmbus_xfer_read_chunk(dev_priv, msg->addr, buf, len,
 450                                             gmbus0_reg, gmbus1_index);
 451                 if (ret)
 452                         return ret;
 453
 454                 rx_size -= len;
 455                 buf += len;
 456         } while (rx_size != 0);
 457
 458         return 0;
 459 }
 460
 461 static int
 462 gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv,
 463                        unsigned short addr, u8 *buf, unsigned int len,
 464                        u32 gmbus1_index)
 465 {
 466         unsigned int chunk_size = len;
 467         u32 val, loop;
 468
 469         val = loop = 0;
 470         while (len && loop < 4) {
 471                 val |= *buf++ << (8 * loop++);
 472                 len -= 1;
 473         }
 474
 475         I915_WRITE_FW(GMBUS3, val);
 476         I915_WRITE_FW(GMBUS1,
 477                       gmbus1_index | GMBUS_CYCLE_WAIT |
 478                       (chunk_size << GMBUS_BYTE_COUNT_SHIFT) |
 479                       (addr << GMBUS_SLAVE_ADDR_SHIFT) |
 480                       GMBUS_SLAVE_WRITE | GMBUS_SW_RDY);
 481         while (len) {
 482                 int ret;
 483
 484                 val = loop = 0;
 485                 do {
 486                         val |= *buf++ << (8 * loop);
 487                 } while (--len && ++loop < 4);
 488
 489                 I915_WRITE_FW(GMBUS3, val);
 490
 491                 ret = gmbus_wait(dev_priv, GMBUS_HW_RDY, GMBUS_HW_RDY_EN);
 492                 if (ret)
 493                         return ret;
 494         }
 495
 496         return 0;
 497 }
 498
 499 static int
 500 gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
 501                  u32 gmbus1_index)
 502 {
 503         u8 *buf = msg->buf;
 504         unsigned int tx_size = msg->len;
 505         unsigned int len;
 506         int ret;
 507
 508         do {
 509                 len = min(tx_size, gmbus_max_xfer_size(dev_priv));
 510
 511                 ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len,
 512                                              gmbus1_index);
 513                 if (ret)
 514                         return ret;
 515
 516                 buf += len;
 517                 tx_size -= len;
 518         } while (tx_size != 0);
 519
 520         return 0;
 521 }
 522
 523 /*
 524  * The gmbus controller can combine a 1 or 2 byte write with another read/write
 525  * that immediately follows it by using an "INDEX" cycle.
 526  */
 527 static bool
 528 gmbus_is_index_xfer(struct i2c_msg *msgs, int i, int num)
 529 {
 530         return (i + 1 < num &&
 531                 msgs[i].addr == msgs[i + 1].addr &&
 532                 !(msgs[i].flags & I2C_M_RD) &&
 533                 (msgs[i].len == 1 || msgs[i].len == 2) &&
 534                 msgs[i + 1].len > 0);
 535 }
 536
 537 static int
 538 gmbus_index_xfer(struct drm_i915_private *dev_priv, struct i2c_msg *msgs,
 539                  u32 gmbus0_reg)
 540 {
 541         u32 gmbus1_index = 0;
 542         u32 gmbus5 = 0;
 543         int ret;
 544
 545         if (msgs[0].len == 2)
 546                 gmbus5 = GMBUS_2BYTE_INDEX_EN |
 547                          msgs[0].buf[1] | (msgs[0].buf[0] << 8);
 548         if (msgs[0].len == 1)
 549                 gmbus1_index = GMBUS_CYCLE_INDEX |
 550                                (msgs[0].buf[0] << GMBUS_SLAVE_INDEX_SHIFT);
 551
 552         /* GMBUS5 holds 16-bit index */
 553         if (gmbus5)
 554                 I915_WRITE_FW(GMBUS5, gmbus5);
 555
 556         if (msgs[1].flags & I2C_M_RD)
 557                 ret = gmbus_xfer_read(dev_priv, &msgs[1], gmbus0_reg,
 558                                       gmbus1_index);
 559         else
 560                 ret = gmbus_xfer_write(dev_priv, &msgs[1], gmbus1_index);
 561
 562         /* Clear GMBUS5 after each index transfer */
 563         if (gmbus5)
 564                 I915_WRITE_FW(GMBUS5, 0);
 565
 566         return ret;
 567 }
 568
 569 static int
 570 do_gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num,
 571               u32 gmbus0_source)
 572 {
 573         struct intel_gmbus *bus = container_of(adapter,
 574                                                struct intel_gmbus,
 575                                                adapter);
 576         struct drm_i915_private *dev_priv = bus->dev_priv;
 577         int i = 0, inc, try = 0;
 578         int ret = 0;
 579
 580         /* Display WA #0868: skl,bxt,kbl,cfl,glk,cnl */
 581         if (IS_GEN9_LP(dev_priv))
 582                 bxt_gmbus_clock_gating(dev_priv, false);
 583         else if (HAS_PCH_SPT(dev_priv) ||
 584                  HAS_PCH_KBP(dev_priv) || HAS_PCH_CNP(dev_priv))
 585                 pch_gmbus_clock_gating(dev_priv, false);
 586
 587 retry:
 588         I915_WRITE_FW(GMBUS0, gmbus0_source | bus->reg0);
 589
 590         for (; i < num; i += inc) {
 591                 inc = 1;
 592                 if (gmbus_is_index_xfer(msgs, i, num)) {
 593                         ret = gmbus_index_xfer(dev_priv, &msgs[i],
 594                                                gmbus0_source | bus->reg0);
 595                         inc = 2; /* an index transmission is two msgs */
 596                 } else if (msgs[i].flags & I2C_M_RD) {
 597                         ret = gmbus_xfer_read(dev_priv, &msgs[i],
 598                                               gmbus0_source | bus->reg0, 0);
 599                 } else {
 600                         ret = gmbus_xfer_write(dev_priv, &msgs[i], 0);
 601                 }
 602
 603                 if (!ret)
 604                         ret = gmbus_wait(dev_priv,
 605                                          GMBUS_HW_WAIT_PHASE, GMBUS_HW_WAIT_EN);
 606                 if (ret == -ETIMEDOUT)
 607                         goto timeout;
 608                 else if (ret)
 609                         goto clear_err;
 610         }
 611
 612         /* Generate a STOP condition on the bus. Note that gmbus can't generata
 613          * a STOP on the very first cycle. To simplify the code we
 614          * unconditionally generate the STOP condition with an additional gmbus
 615          * cycle. */
 616         I915_WRITE_FW(GMBUS1, GMBUS_CYCLE_STOP | GMBUS_SW_RDY);
 617
 618         /* Mark the GMBUS interface as disabled after waiting for idle.
 619          * We will re-enable it at the start of the next xfer,
 620          * till then let it sleep.
 621          */
 622         if (gmbus_wait_idle(dev_priv)) {
 623                 DRM_DEBUG_KMS("GMBUS [%s] timed out waiting for idle\n",
 624                          adapter->name);
 625                 ret = -ETIMEDOUT;
 626         }
 627         I915_WRITE_FW(GMBUS0, 0);
 628         ret = ret ?: i;
 629         goto out;
 630
 631 clear_err:
 632         /*
 633          * Wait for bus to IDLE before clearing NAK.
 634          * If we clear the NAK while bus is still active, then it will stay
 635          * active and the next transaction may fail.
 636          *
 637          * If no ACK is received during the address phase of a transaction, the
 638          * adapter must report -ENXIO. It is not clear what to return if no ACK
 639          * is received at other times. But we have to be careful to not return
 640          * spurious -ENXIO because that will prevent i2c and drm edid functions
 641          * from retrying. So return -ENXIO only when gmbus properly quiescents -
 642          * timing out seems to happen when there _is_ a ddc chip present, but
 643          * it's slow responding and only answers on the 2nd retry.
 644          */
 645         ret = -ENXIO;
 646         if (gmbus_wait_idle(dev_priv)) {
 647                 DRM_DEBUG_KMS("GMBUS [%s] timed out after NAK\n",
 648                               adapter->name);
 649                 ret = -ETIMEDOUT;
 650         }
 651
 652         /* Toggle the Software Clear Interrupt bit. This has the effect
 653          * of resetting the GMBUS controller and so clearing the
 654          * BUS_ERROR raised by the slave's NAK.
 655          */
 656         I915_WRITE_FW(GMBUS1, GMBUS_SW_CLR_INT);
 657         I915_WRITE_FW(GMBUS1, 0);
 658         I915_WRITE_FW(GMBUS0, 0);
 659
 660         DRM_DEBUG_KMS("GMBUS [%s] NAK for addr: %04x %c(%d)\n",
 661                          adapter->name, msgs[i].addr,
 662                          (msgs[i].flags & I2C_M_RD) ? 'r' : 'w', msgs[i].len);
 663
 664         /*
 665          * Passive adapters sometimes NAK the first probe. Retry the first
 666          * message once on -ENXIO for GMBUS transfers; the bit banging algorithm
 667          * has retries internally. See also the retry loop in
 668          * drm_do_probe_ddc_edid, which bails out on the first -ENXIO.
 669          */
 670         if (ret == -ENXIO && i == 0 && try++ == 0) {
 671                 DRM_DEBUG_KMS("GMBUS [%s] NAK on first message, retry\n",
 672                               adapter->name);
 673                 goto retry;
 674         }
 675
 676         goto out;
 677
 678 timeout:
 679         DRM_DEBUG_KMS("GMBUS [%s] timed out, falling back to bit banging on pin %d\n",
 680                       bus->adapter.name, bus->reg0 & 0xff);
 681         I915_WRITE_FW(GMBUS0, 0);
 682
 683         /*
 684          * Hardware may not support GMBUS over these pins? Try GPIO bitbanging
 685          * instead. Use EAGAIN to have i2c core retry.
 686          */
 687         ret = -EAGAIN;
 688
 689 out:
 690         /* Display WA #0868: skl,bxt,kbl,cfl,glk,cnl */
 691         if (IS_GEN9_LP(dev_priv))
 692                 bxt_gmbus_clock_gating(dev_priv, true);
 693         else if (HAS_PCH_SPT(dev_priv) ||
 694                  HAS_PCH_KBP(dev_priv) || HAS_PCH_CNP(dev_priv))
 695                 pch_gmbus_clock_gating(dev_priv, true);
 696
 697         return ret;
 698 }
 699
 700 static int
 701 gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
 702 {
 703         struct intel_gmbus *bus = container_of(adapter, struct intel_gmbus,
 704                                                adapter);
 705         struct drm_i915_private *dev_priv = bus->dev_priv;
 706         int ret;
 707
 708         intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
 709
 710         if (bus->force_bit) {
 711                 ret = i2c_bit_algo.master_xfer(adapter, msgs, num);
 712                 if (ret < 0)
 713                         bus->force_bit &= ~GMBUS_FORCE_BIT_RETRY;
 714         } else {
 715                 ret = do_gmbus_xfer(adapter, msgs, num, 0);
 716                 if (ret == -EAGAIN)
 717                         bus->force_bit |= GMBUS_FORCE_BIT_RETRY;
 718         }
 719
 720         intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
 721
 722         return ret;
 723 }
 724
 725 int intel_gmbus_output_aksv(struct i2c_adapter *adapter)
 726 {
 727         struct intel_gmbus *bus = container_of(adapter, struct intel_gmbus,
 728                                                adapter);
 729         struct drm_i915_private *dev_priv = bus->dev_priv;
 730         int ret;
 731         u8 cmd = DRM_HDCP_DDC_AKSV;
 732         u8 buf[DRM_HDCP_KSV_LEN] = { 0 };
 733         struct i2c_msg msgs[] = {
 734                 {
 735                         .addr = DRM_HDCP_DDC_ADDR,
 736                         .flags = 0,
 737                         .len = sizeof(cmd),
 738                         .buf = &cmd,
 739                 },
 740                 {
 741                         .addr = DRM_HDCP_DDC_ADDR,
 742                         .flags = 0,
 743                         .len = sizeof(buf),
 744                         .buf = buf,
 745                 }
 746         };
 747
 748         intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
 749         mutex_lock(&dev_priv->gmbus_mutex);
 750
 751         /*
 752          * In order to output Aksv to the receiver, use an indexed write to
 753          * pass the i2c command, and tell GMBUS to use the HW-provided value
 754          * instead of sourcing GMBUS3 for the data.
 755          */
 756         ret = do_gmbus_xfer(adapter, msgs, ARRAY_SIZE(msgs), GMBUS_AKSV_SELECT);
 757
 758         mutex_unlock(&dev_priv->gmbus_mutex);
 759         intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
 760
 761         return ret;
 762 }
 763
 764 static u32 gmbus_func(struct i2c_adapter *adapter)
 765 {
 766         return i2c_bit_algo.functionality(adapter) &
 767                 (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
 768                 /* I2C_FUNC_10BIT_ADDR | */
 769                 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
 770                 I2C_FUNC_SMBUS_BLOCK_PROC_CALL);
 771 }
 772
 773 static const struct i2c_algorithm gmbus_algorithm = {
 774         .master_xfer    = gmbus_xfer,
 775         .functionality  = gmbus_func
 776 };
 777
 778 static void gmbus_lock_bus(struct i2c_adapter *adapter,
 779                            unsigned int flags)
 780 {
 781         struct intel_gmbus *bus = to_intel_gmbus(adapter);
 782         struct drm_i915_private *dev_priv = bus->dev_priv;
 783
 784         mutex_lock(&dev_priv->gmbus_mutex);
 785 }
 786
 787 static int gmbus_trylock_bus(struct i2c_adapter *adapter,
 788                              unsigned int flags)
 789 {
 790         struct intel_gmbus *bus = to_intel_gmbus(adapter);
 791         struct drm_i915_private *dev_priv = bus->dev_priv;
 792
 793         return mutex_trylock(&dev_priv->gmbus_mutex);
 794 }
 795
 796 static void gmbus_unlock_bus(struct i2c_adapter *adapter,
 797                              unsigned int flags)
 798 {
 799         struct intel_gmbus *bus = to_intel_gmbus(adapter);
 800         struct drm_i915_private *dev_priv = bus->dev_priv;
 801
 802         mutex_unlock(&dev_priv->gmbus_mutex);
 803 }
 804
 805 static const struct i2c_lock_operations gmbus_lock_ops = {
 806         .lock_bus =    gmbus_lock_bus,
 807         .trylock_bus = gmbus_trylock_bus,
 808         .unlock_bus =  gmbus_unlock_bus,
 809 };
 810
 811 /**
 812  * intel_gmbus_setup - instantiate all Intel i2c GMBuses
 813  * @dev_priv: i915 device private
 814  */
 815 int intel_setup_gmbus(struct drm_i915_private *dev_priv)
 816 {
 817         struct pci_dev *pdev = dev_priv->drm.pdev;
 818         struct intel_gmbus *bus;
 819         unsigned int pin;
 820         int ret;
 821
 822         if (INTEL_INFO(dev_priv)->num_pipes == 0)
 823                 return 0;
 824
 825         if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
 826                 dev_priv->gpio_mmio_base = VLV_DISPLAY_BASE;
 827         else if (!HAS_GMCH_DISPLAY(dev_priv))
 828                 dev_priv->gpio_mmio_base =
 829                         i915_mmio_reg_offset(PCH_GPIOA) -
 830                         i915_mmio_reg_offset(GPIOA);
 831
 832         mutex_init(&dev_priv->gmbus_mutex);
 833         init_waitqueue_head(&dev_priv->gmbus_wait_queue);
 834
 835         for (pin = 0; pin < ARRAY_SIZE(dev_priv->gmbus); pin++) {
 836                 if (!intel_gmbus_is_valid_pin(dev_priv, pin))
 837                         continue;
 838
 839                 bus = &dev_priv->gmbus[pin];
 840
 841                 bus->adapter.owner = THIS_MODULE;
 842                 bus->adapter.class = I2C_CLASS_DDC;
 843                 snprintf(bus->adapter.name,
 844                          sizeof(bus->adapter.name),
 845                          "i915 gmbus %s",
 846                          get_gmbus_pin(dev_priv, pin)->name);
 847
 848                 bus->adapter.dev.parent = &pdev->dev;
 849                 bus->dev_priv = dev_priv;
 850
 851                 bus->adapter.algo = &gmbus_algorithm;
 852                 bus->adapter.lock_ops = &gmbus_lock_ops;
 853
 854                 /*
 855                  * We wish to retry with bit banging
 856                  * after a timed out GMBUS attempt.
 857                  */
 858                 bus->adapter.retries = 1;
 859
 860                 /* By default use a conservative clock rate */
 861                 bus->reg0 = pin | GMBUS_RATE_100KHZ;
 862
 863                 /* gmbus seems to be broken on i830 */
 864                 if (IS_I830(dev_priv))
 865                         bus->force_bit = 1;
 866
 867                 intel_gpio_setup(bus, pin);
 868
 869                 ret = i2c_add_adapter(&bus->adapter);
 870                 if (ret)
 871                         goto err;
 872         }
 873
 874         intel_i2c_reset(dev_priv);
 875
 876         return 0;
 877
 878 err:
 879         while (pin--) {
 880                 if (!intel_gmbus_is_valid_pin(dev_priv, pin))
 881                         continue;
 882
 883                 bus = &dev_priv->gmbus[pin];
 884                 i2c_del_adapter(&bus->adapter);
 885         }
 886         return ret;
 887 }
 888
 889 struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv,
 890                                             unsigned int pin)
 891 {
 892         if (WARN_ON(!intel_gmbus_is_valid_pin(dev_priv, pin)))
 893                 return NULL;
 894
 895         return &dev_priv->gmbus[pin].adapter;
 896 }
 897
 898 void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
 899 {
 900         struct intel_gmbus *bus = to_intel_gmbus(adapter);
 901
 902         bus->reg0 = (bus->reg0 & ~(0x3 << 8)) | speed;
 903 }
 904
 905 void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
 906 {
 907         struct intel_gmbus *bus = to_intel_gmbus(adapter);
 908         struct drm_i915_private *dev_priv = bus->dev_priv;
 909
 910         mutex_lock(&dev_priv->gmbus_mutex);
 911
 912         bus->force_bit += force_bit ? 1 : -1;
 913         DRM_DEBUG_KMS("%sabling bit-banging on %s. force bit now %d\n",
 914                       force_bit ? "en" : "dis", adapter->name,
 915                       bus->force_bit);
 916
 917         mutex_unlock(&dev_priv->gmbus_mutex);
 918 }
 919
 920 void intel_teardown_gmbus(struct drm_i915_private *dev_priv)
 921 {
 922         struct intel_gmbus *bus;
 923         unsigned int pin;
 924
 925         for (pin = 0; pin < ARRAY_SIZE(dev_priv->gmbus); pin++) {
 926                 if (!intel_gmbus_is_valid_pin(dev_priv, pin))
 927                         continue;
 928
 929                 bus = &dev_priv->gmbus[pin];
 930                 i2c_del_adapter(&bus->adapter);
 931         }
 932 }