drivers/acpi/acpica/hwregs.c

   1
   2 /*******************************************************************************
   3  *
   4  * Module Name: hwregs - Read/write access functions for the various ACPI
   5  *                       control and status registers.
   6  *
   7  ******************************************************************************/
   8
   9 /*
  10  * Copyright (C) 2000 - 2008, Intel Corp.
  11  * All rights reserved.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions, and the following disclaimer,
  18  *    without modification.
  19  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  20  *    substantially similar to the "NO WARRANTY" disclaimer below
  21  *    ("Disclaimer") and any redistribution must be conditioned upon
  22  *    including a substantially similar Disclaimer requirement for further
  23  *    binary redistribution.
  24  * 3. Neither the names of the above-listed copyright holders nor the names
  25  *    of any contributors may be used to endorse or promote products derived
  26  *    from this software without specific prior written permission.
  27  *
  28  * Alternatively, this software may be distributed under the terms of the
  29  * GNU General Public License ("GPL") version 2 as published by the Free
  30  * Software Foundation.
  31  *
  32  * NO WARRANTY
  33  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  34  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  35  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  36  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  37  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  38  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  39  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  40  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  41  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  42  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  43  * POSSIBILITY OF SUCH DAMAGES.
  44  */
  45
  46 #include <acpi/acpi.h>
  47 #include "accommon.h"
  48 #include "acnamesp.h"
  49 #include "acevents.h"
  50
  51 #define _COMPONENT          ACPI_HARDWARE
  52 ACPI_MODULE_NAME("hwregs")
  53
  54 /* Local Prototypes */
  55 static acpi_status
  56 acpi_hw_read_multiple(u32 *value,
  57                       struct acpi_generic_address *register_a,
  58                       struct acpi_generic_address *register_b);
  59
  60 static acpi_status
  61 acpi_hw_write_multiple(u32 value,
  62                        struct acpi_generic_address *register_a,
  63                        struct acpi_generic_address *register_b);
  64
  65 /*******************************************************************************
  66  *
  67  * FUNCTION:    acpi_hw_clear_acpi_status
  68  *
  69  * PARAMETERS:  None
  70  *
  71  * RETURN:      Status
  72  *
  73  * DESCRIPTION: Clears all fixed and general purpose status bits
  74  *
  75  ******************************************************************************/
  76
  77 acpi_status acpi_hw_clear_acpi_status(void)
  78 {
  79         acpi_status status;
  80         acpi_cpu_flags lock_flags = 0;
  81
  82         ACPI_FUNCTION_TRACE(hw_clear_acpi_status);
  83
  84         ACPI_DEBUG_PRINT((ACPI_DB_IO, "About to write %04X to %0llX\n",
  85                           ACPI_BITMASK_ALL_FIXED_STATUS,
  86                           acpi_gbl_xpm1a_status.address));
  87
  88         lock_flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);
  89
  90         /* Clear the fixed events in PM1 A/B */
  91
  92         status = acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS,
  93                                         ACPI_BITMASK_ALL_FIXED_STATUS);
  94         if (ACPI_FAILURE(status)) {
  95                 goto unlock_and_exit;
  96         }
  97
  98         /* Clear the GPE Bits in all GPE registers in all GPE blocks */
  99
 100         status = acpi_ev_walk_gpe_list(acpi_hw_clear_gpe_block, NULL);
 101
 102       unlock_and_exit:
 103         acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);
 104         return_ACPI_STATUS(status);
 105 }
 106
 107 /*******************************************************************************
 108  *
 109  * FUNCTION:    acpi_hw_get_register_bit_mask
 110  *
 111  * PARAMETERS:  register_id         - Index of ACPI Register to access
 112  *
 113  * RETURN:      The bitmask to be used when accessing the register
 114  *
 115  * DESCRIPTION: Map register_id into a register bitmask.
 116  *
 117  ******************************************************************************/
 118
 119 struct acpi_bit_register_info *acpi_hw_get_bit_register_info(u32 register_id)
 120 {
 121         ACPI_FUNCTION_ENTRY();
 122
 123         if (register_id > ACPI_BITREG_MAX) {
 124                 ACPI_ERROR((AE_INFO, "Invalid BitRegister ID: %X",
 125                             register_id));
 126                 return (NULL);
 127         }
 128
 129         return (&acpi_gbl_bit_register_info[register_id]);
 130 }
 131
 132 /******************************************************************************
 133  *
 134  * FUNCTION:    acpi_hw_write_pm1_control
 135  *
 136  * PARAMETERS:  pm1a_control        - Value to be written to PM1A control
 137  *              pm1b_control        - Value to be written to PM1B control
 138  *
 139  * RETURN:      Status
 140  *
 141  * DESCRIPTION: Write the PM1 A/B control registers. These registers are
 142  *              different than than the PM1 A/B status and enable registers
 143  *              in that different values can be written to the A/B registers.
 144  *              Most notably, the SLP_TYP bits can be different, as per the
 145  *              values returned from the _Sx predefined methods.
 146  *
 147  ******************************************************************************/
 148
 149 acpi_status acpi_hw_write_pm1_control(u32 pm1a_control, u32 pm1b_control)
 150 {
 151         acpi_status status;
 152
 153         ACPI_FUNCTION_TRACE(hw_write_pm1_control);
 154
 155         status = acpi_write(pm1a_control, &acpi_gbl_FADT.xpm1a_control_block);
 156         if (ACPI_FAILURE(status)) {
 157                 return_ACPI_STATUS(status);
 158         }
 159
 160         if (acpi_gbl_FADT.xpm1b_control_block.address) {
 161                 status =
 162                     acpi_write(pm1b_control,
 163                                &acpi_gbl_FADT.xpm1b_control_block);
 164         }
 165         return_ACPI_STATUS(status);
 166 }
 167
 168 /******************************************************************************
 169  *
 170  * FUNCTION:    acpi_hw_register_read
 171  *
 172  * PARAMETERS:  register_id         - ACPI Register ID
 173  *              return_value        - Where the register value is returned
 174  *
 175  * RETURN:      Status and the value read.
 176  *
 177  * DESCRIPTION: Read from the specified ACPI register
 178  *
 179  ******************************************************************************/
 180 acpi_status
 181 acpi_hw_register_read(u32 register_id, u32 * return_value)
 182 {
 183         u32 value = 0;
 184         acpi_status status;
 185
 186         ACPI_FUNCTION_TRACE(hw_register_read);
 187
 188         switch (register_id) {
 189         case ACPI_REGISTER_PM1_STATUS:  /* PM1 A/B: 16-bit access each */
 190
 191                 status = acpi_hw_read_multiple(&value,
 192                                                &acpi_gbl_xpm1a_status,
 193                                                &acpi_gbl_xpm1b_status);
 194                 break;
 195
 196         case ACPI_REGISTER_PM1_ENABLE:  /* PM1 A/B: 16-bit access each */
 197
 198                 status = acpi_hw_read_multiple(&value,
 199                                                &acpi_gbl_xpm1a_enable,
 200                                                &acpi_gbl_xpm1b_enable);
 201                 break;
 202
 203         case ACPI_REGISTER_PM1_CONTROL: /* PM1 A/B: 16-bit access each */
 204
 205                 status = acpi_hw_read_multiple(&value,
 206                                                &acpi_gbl_FADT.
 207                                                xpm1a_control_block,
 208                                                &acpi_gbl_FADT.
 209                                                xpm1b_control_block);
 210
 211                 /*
 212                  * Zero the write-only bits. From the ACPI specification, "Hardware
 213                  * Write-Only Bits": "Upon reads to registers with write-only bits,
 214                  * software masks out all write-only bits."
 215                  */
 216                 value &= ~ACPI_PM1_CONTROL_WRITEONLY_BITS;
 217                 break;
 218
 219         case ACPI_REGISTER_PM2_CONTROL: /* 8-bit access */
 220
 221                 status = acpi_read(&value, &acpi_gbl_FADT.xpm2_control_block);
 222                 break;
 223
 224         case ACPI_REGISTER_PM_TIMER:    /* 32-bit access */
 225
 226                 status = acpi_read(&value, &acpi_gbl_FADT.xpm_timer_block);
 227                 break;
 228
 229         case ACPI_REGISTER_SMI_COMMAND_BLOCK:   /* 8-bit access */
 230
 231                 status =
 232                     acpi_hw_read_port(acpi_gbl_FADT.smi_command, &value, 8);
 233                 break;
 234
 235         default:
 236                 ACPI_ERROR((AE_INFO, "Unknown Register ID: %X", register_id));
 237                 status = AE_BAD_PARAMETER;
 238                 break;
 239         }
 240
 241         if (ACPI_SUCCESS(status)) {
 242                 *return_value = value;
 243         }
 244
 245         return_ACPI_STATUS(status);
 246 }
 247
 248 /******************************************************************************
 249  *
 250  * FUNCTION:    acpi_hw_register_write
 251  *
 252  * PARAMETERS:  register_id         - ACPI Register ID
 253  *              Value               - The value to write
 254  *
 255  * RETURN:      Status
 256  *
 257  * DESCRIPTION: Write to the specified ACPI register
 258  *
 259  * NOTE: In accordance with the ACPI specification, this function automatically
 260  * preserves the value of the following bits, meaning that these bits cannot be
 261  * changed via this interface:
 262  *
 263  * PM1_CONTROL[0] = SCI_EN
 264  * PM1_CONTROL[9]
 265  * PM1_STATUS[11]
 266  *
 267  * ACPI References:
 268  * 1) Hardware Ignored Bits: When software writes to a register with ignored
 269  *      bit fields, it preserves the ignored bit fields
 270  * 2) SCI_EN: OSPM always preserves this bit position
 271  *
 272  ******************************************************************************/
 273
 274 acpi_status acpi_hw_register_write(u32 register_id, u32 value)
 275 {
 276         acpi_status status;
 277         u32 read_value;
 278
 279         ACPI_FUNCTION_TRACE(hw_register_write);
 280
 281         switch (register_id) {
 282         case ACPI_REGISTER_PM1_STATUS:  /* PM1 A/B: 16-bit access each */
 283                 /*
 284                  * Handle the "ignored" bit in PM1 Status. According to the ACPI
 285                  * specification, ignored bits are to be preserved when writing.
 286                  * Normally, this would mean a read/modify/write sequence. However,
 287                  * preserving a bit in the status register is different. Writing a
 288                  * one clears the status, and writing a zero preserves the status.
 289                  * Therefore, we must always write zero to the ignored bit.
 290                  *
 291                  * This behavior is clarified in the ACPI 4.0 specification.
 292                  */
 293                 value &= ~ACPI_PM1_STATUS_PRESERVED_BITS;
 294
 295                 status = acpi_hw_write_multiple(value,
 296                                                 &acpi_gbl_xpm1a_status,
 297                                                 &acpi_gbl_xpm1b_status);
 298                 break;
 299
 300         case ACPI_REGISTER_PM1_ENABLE:  /* PM1 A/B: 16-bit access */
 301
 302                 status = acpi_hw_write_multiple(value,
 303                                                 &acpi_gbl_xpm1a_enable,
 304                                                 &acpi_gbl_xpm1b_enable);
 305                 break;
 306
 307         case ACPI_REGISTER_PM1_CONTROL: /* PM1 A/B: 16-bit access each */
 308
 309                 /*
 310                  * Perform a read first to preserve certain bits (per ACPI spec)
 311                  * Note: This includes SCI_EN, we never want to change this bit
 312                  */
 313                 status = acpi_hw_read_multiple(&read_value,
 314                                                &acpi_gbl_FADT.
 315                                                xpm1a_control_block,
 316                                                &acpi_gbl_FADT.
 317                                                xpm1b_control_block);
 318                 if (ACPI_FAILURE(status)) {
 319                         goto exit;
 320                 }
 321
 322                 /* Insert the bits to be preserved */
 323
 324                 ACPI_INSERT_BITS(value, ACPI_PM1_CONTROL_PRESERVED_BITS,
 325                                  read_value);
 326
 327                 /* Now we can write the data */
 328
 329                 status = acpi_hw_write_multiple(value,
 330                                                 &acpi_gbl_FADT.
 331                                                 xpm1a_control_block,
 332                                                 &acpi_gbl_FADT.
 333                                                 xpm1b_control_block);
 334                 break;
 335
 336         case ACPI_REGISTER_PM2_CONTROL: /* 8-bit access */
 337
 338                 /*
 339                  * For control registers, all reserved bits must be preserved,
 340                  * as per the ACPI spec.
 341                  */
 342                 status =
 343                     acpi_read(&read_value, &acpi_gbl_FADT.xpm2_control_block);
 344                 if (ACPI_FAILURE(status)) {
 345                         goto exit;
 346                 }
 347
 348                 /* Insert the bits to be preserved */
 349
 350                 ACPI_INSERT_BITS(value, ACPI_PM2_CONTROL_PRESERVED_BITS,
 351                                  read_value);
 352
 353                 status = acpi_write(value, &acpi_gbl_FADT.xpm2_control_block);
 354                 break;
 355
 356         case ACPI_REGISTER_PM_TIMER:    /* 32-bit access */
 357
 358                 status = acpi_write(value, &acpi_gbl_FADT.xpm_timer_block);
 359                 break;
 360
 361         case ACPI_REGISTER_SMI_COMMAND_BLOCK:   /* 8-bit access */
 362
 363                 /* SMI_CMD is currently always in IO space */
 364
 365                 status =
 366                     acpi_hw_write_port(acpi_gbl_FADT.smi_command, value, 8);
 367                 break;
 368
 369         default:
 370                 ACPI_ERROR((AE_INFO, "Unknown Register ID: %X", register_id));
 371                 status = AE_BAD_PARAMETER;
 372                 break;
 373         }
 374
 375       exit:
 376         return_ACPI_STATUS(status);
 377 }
 378
 379 /******************************************************************************
 380  *
 381  * FUNCTION:    acpi_hw_read_multiple
 382  *
 383  * PARAMETERS:  Value               - Where the register value is returned
 384  *              register_a           - First ACPI register (required)
 385  *              register_b           - Second ACPI register (optional)
 386  *
 387  * RETURN:      Status
 388  *
 389  * DESCRIPTION: Read from the specified two-part ACPI register (such as PM1 A/B)
 390  *
 391  ******************************************************************************/
 392
 393 static acpi_status
 394 acpi_hw_read_multiple(u32 *value,
 395                       struct acpi_generic_address *register_a,
 396                       struct acpi_generic_address *register_b)
 397 {
 398         u32 value_a = 0;
 399         u32 value_b = 0;
 400         acpi_status status;
 401
 402         /* The first register is always required */
 403
 404         status = acpi_read(&value_a, register_a);
 405         if (ACPI_FAILURE(status)) {
 406                 return (status);
 407         }
 408
 409         /* Second register is optional */
 410
 411         if (register_b->address) {
 412                 status = acpi_read(&value_b, register_b);
 413                 if (ACPI_FAILURE(status)) {
 414                         return (status);
 415                 }
 416         }
 417
 418         /*
 419          * OR the two return values together. No shifting or masking is necessary,
 420          * because of how the PM1 registers are defined in the ACPI specification:
 421          *
 422          * "Although the bits can be split between the two register blocks (each
 423          * register block has a unique pointer within the FADT), the bit positions
 424          * are maintained. The register block with unimplemented bits (that is,
 425          * those implemented in the other register block) always returns zeros,
 426          * and writes have no side effects"
 427          */
 428         *value = (value_a | value_b);
 429         return (AE_OK);
 430 }
 431
 432 /******************************************************************************
 433  *
 434  * FUNCTION:    acpi_hw_write_multiple
 435  *
 436  * PARAMETERS:  Value               - The value to write
 437  *              register_a           - First ACPI register (required)
 438  *              register_b           - Second ACPI register (optional)
 439  *
 440  * RETURN:      Status
 441  *
 442  * DESCRIPTION: Write to the specified two-part ACPI register (such as PM1 A/B)
 443  *
 444  ******************************************************************************/
 445
 446 static acpi_status
 447 acpi_hw_write_multiple(u32 value,
 448                        struct acpi_generic_address *register_a,
 449                        struct acpi_generic_address *register_b)
 450 {
 451         acpi_status status;
 452
 453         /* The first register is always required */
 454
 455         status = acpi_write(value, register_a);
 456         if (ACPI_FAILURE(status)) {
 457                 return (status);
 458         }
 459
 460         /*
 461          * Second register is optional
 462          *
 463          * No bit shifting or clearing is necessary, because of how the PM1
 464          * registers are defined in the ACPI specification:
 465          *
 466          * "Although the bits can be split between the two register blocks (each
 467          * register block has a unique pointer within the FADT), the bit positions
 468          * are maintained. The register block with unimplemented bits (that is,
 469          * those implemented in the other register block) always returns zeros,
 470          * and writes have no side effects"
 471          */
 472         if (register_b->address) {
 473                 status = acpi_write(value, register_b);
 474         }
 475
 476         return (status);
 477 }