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kernel/linux-rt-4.4.41/drivers/acpi/acpica/hwregs.c 19.5 KB
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  /*******************************************************************************
   *
   * Module Name: hwregs - Read/write access functions for the various ACPI
   *                       control and status registers.
   *
   ******************************************************************************/
  
  /*
   * Copyright (C) 2000 - 2015, Intel Corp.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions, and the following disclaimer,
   *    without modification.
   * 2. Redistributions in binary form must reproduce at minimum a disclaimer
   *    substantially similar to the "NO WARRANTY" disclaimer below
   *    ("Disclaimer") and any redistribution must be conditioned upon
   *    including a substantially similar Disclaimer requirement for further
   *    binary redistribution.
   * 3. Neither the names of the above-listed copyright holders nor the names
   *    of any contributors may be used to endorse or promote products derived
   *    from this software without specific prior written permission.
   *
   * Alternatively, this software may be distributed under the terms of the
   * GNU General Public License ("GPL") version 2 as published by the Free
   * Software Foundation.
   *
   * NO WARRANTY
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
   * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGES.
   */
  
  #include <acpi/acpi.h>
  #include "accommon.h"
  #include "acevents.h"
  
  #define _COMPONENT          ACPI_HARDWARE
  ACPI_MODULE_NAME("hwregs")
  
  #if (!ACPI_REDUCED_HARDWARE)
  /* Local Prototypes */
  static acpi_status
  acpi_hw_read_multiple(u32 *value,
  		      struct acpi_generic_address *register_a,
  		      struct acpi_generic_address *register_b);
  
  static acpi_status
  acpi_hw_write_multiple(u32 value,
  		       struct acpi_generic_address *register_a,
  		       struct acpi_generic_address *register_b);
  
  #endif				/* !ACPI_REDUCED_HARDWARE */
  
  /******************************************************************************
   *
   * FUNCTION:    acpi_hw_validate_register
   *
   * PARAMETERS:  reg                 - GAS register structure
   *              max_bit_width       - Max bit_width supported (32 or 64)
   *              address             - Pointer to where the gas->address
   *                                    is returned
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Validate the contents of a GAS register. Checks the GAS
   *              pointer, Address, space_id, bit_width, and bit_offset.
   *
   ******************************************************************************/
  
  acpi_status
  acpi_hw_validate_register(struct acpi_generic_address *reg,
  			  u8 max_bit_width, u64 *address)
  {
  
  	/* Must have a valid pointer to a GAS structure */
  
  	if (!reg) {
  		return (AE_BAD_PARAMETER);
  	}
  
  	/*
  	 * Copy the target address. This handles possible alignment issues.
  	 * Address must not be null. A null address also indicates an optional
  	 * ACPI register that is not supported, so no error message.
  	 */
  	ACPI_MOVE_64_TO_64(address, &reg->address);
  	if (!(*address)) {
  		return (AE_BAD_ADDRESS);
  	}
  
  	/* Validate the space_ID */
  
  	if ((reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) &&
  	    (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
  		ACPI_ERROR((AE_INFO,
  			    "Unsupported address space: 0x%X", reg->space_id));
  		return (AE_SUPPORT);
  	}
  
  	/* Validate the bit_width */
  
  	if ((reg->bit_width != 8) &&
  	    (reg->bit_width != 16) &&
  	    (reg->bit_width != 32) && (reg->bit_width != max_bit_width)) {
  		ACPI_ERROR((AE_INFO,
  			    "Unsupported register bit width: 0x%X",
  			    reg->bit_width));
  		return (AE_SUPPORT);
  	}
  
  	/* Validate the bit_offset. Just a warning for now. */
  
  	if (reg->bit_offset != 0) {
  		ACPI_WARNING((AE_INFO,
  			      "Unsupported register bit offset: 0x%X",
  			      reg->bit_offset));
  	}
  
  	return (AE_OK);
  }
  
  /******************************************************************************
   *
   * FUNCTION:    acpi_hw_read
   *
   * PARAMETERS:  value               - Where the value is returned
   *              reg                 - GAS register structure
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Read from either memory or IO space. This is a 32-bit max
   *              version of acpi_read, used internally since the overhead of
   *              64-bit values is not needed.
   *
   * LIMITATIONS: <These limitations also apply to acpi_hw_write>
   *      bit_width must be exactly 8, 16, or 32.
   *      space_ID must be system_memory or system_IO.
   *      bit_offset and access_width are currently ignored, as there has
   *          not been a need to implement these.
   *
   ******************************************************************************/
  
  acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg)
  {
  	u64 address;
  	u64 value64;
  	acpi_status status;
  
  	ACPI_FUNCTION_NAME(hw_read);
  
  	/* Validate contents of the GAS register */
  
  	status = acpi_hw_validate_register(reg, 32, &address);
  	if (ACPI_FAILURE(status)) {
  		return (status);
  	}
  
  	/* Initialize entire 32-bit return value to zero */
  
  	*value = 0;
  
  	/*
  	 * Two address spaces supported: Memory or IO. PCI_Config is
  	 * not supported here because the GAS structure is insufficient
  	 */
  	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
  		status = acpi_os_read_memory((acpi_physical_address)
  					     address, &value64, reg->bit_width);
  
  		*value = (u32)value64;
  	} else {		/* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
  
  		status = acpi_hw_read_port((acpi_io_address)
  					   address, value, reg->bit_width);
  	}
  
  	ACPI_DEBUG_PRINT((ACPI_DB_IO,
  			  "Read:  %8.8X width %2d from %8.8X%8.8X (%s)
  ",
  			  *value, reg->bit_width, ACPI_FORMAT_UINT64(address),
  			  acpi_ut_get_region_name(reg->space_id)));
  
  	return (status);
  }
  
  /******************************************************************************
   *
   * FUNCTION:    acpi_hw_write
   *
   * PARAMETERS:  value               - Value to be written
   *              reg                 - GAS register structure
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Write to either memory or IO space. This is a 32-bit max
   *              version of acpi_write, used internally since the overhead of
   *              64-bit values is not needed.
   *
   ******************************************************************************/
  
  acpi_status acpi_hw_write(u32 value, struct acpi_generic_address *reg)
  {
  	u64 address;
  	acpi_status status;
  
  	ACPI_FUNCTION_NAME(hw_write);
  
  	/* Validate contents of the GAS register */
  
  	status = acpi_hw_validate_register(reg, 32, &address);
  	if (ACPI_FAILURE(status)) {
  		return (status);
  	}
  
  	/*
  	 * Two address spaces supported: Memory or IO. PCI_Config is
  	 * not supported here because the GAS structure is insufficient
  	 */
  	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
  		status = acpi_os_write_memory((acpi_physical_address)
  					      address, (u64)value,
  					      reg->bit_width);
  	} else {		/* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
  
  		status = acpi_hw_write_port((acpi_io_address)
  					    address, value, reg->bit_width);
  	}
  
  	ACPI_DEBUG_PRINT((ACPI_DB_IO,
  			  "Wrote: %8.8X width %2d   to %8.8X%8.8X (%s)
  ",
  			  value, reg->bit_width, ACPI_FORMAT_UINT64(address),
  			  acpi_ut_get_region_name(reg->space_id)));
  
  	return (status);
  }
  
  #if (!ACPI_REDUCED_HARDWARE)
  /*******************************************************************************
   *
   * FUNCTION:    acpi_hw_clear_acpi_status
   *
   * PARAMETERS:  None
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Clears all fixed and general purpose status bits
   *
   ******************************************************************************/
  
  acpi_status acpi_hw_clear_acpi_status(void)
  {
  	acpi_status status;
  	acpi_cpu_flags lock_flags = 0;
  
  	ACPI_FUNCTION_TRACE(hw_clear_acpi_status);
  
  	ACPI_DEBUG_PRINT((ACPI_DB_IO, "About to write %04X to %8.8X%8.8X
  ",
  			  ACPI_BITMASK_ALL_FIXED_STATUS,
  			  ACPI_FORMAT_UINT64(acpi_gbl_xpm1a_status.address)));
  
  	raw_spin_lock_irqsave(acpi_gbl_hardware_lock, lock_flags);
  
  	/* Clear the fixed events in PM1 A/B */
  
  	status = acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS,
  					ACPI_BITMASK_ALL_FIXED_STATUS);
  
  	raw_spin_unlock_irqrestore(acpi_gbl_hardware_lock, lock_flags);
  
  	if (ACPI_FAILURE(status)) {
  		goto exit;
  	}
  
  	/* Clear the GPE Bits in all GPE registers in all GPE blocks */
  
  	status = acpi_ev_walk_gpe_list(acpi_hw_clear_gpe_block, NULL);
  
  exit:
  	return_ACPI_STATUS(status);
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_hw_get_bit_register_info
   *
   * PARAMETERS:  register_id         - Index of ACPI Register to access
   *
   * RETURN:      The bitmask to be used when accessing the register
   *
   * DESCRIPTION: Map register_id into a register bitmask.
   *
   ******************************************************************************/
  
  struct acpi_bit_register_info *acpi_hw_get_bit_register_info(u32 register_id)
  {
  	ACPI_FUNCTION_ENTRY();
  
  	if (register_id > ACPI_BITREG_MAX) {
  		ACPI_ERROR((AE_INFO, "Invalid BitRegister ID: 0x%X",
  			    register_id));
  		return (NULL);
  	}
  
  	return (&acpi_gbl_bit_register_info[register_id]);
  }
  
  /******************************************************************************
   *
   * FUNCTION:    acpi_hw_write_pm1_control
   *
   * PARAMETERS:  pm1a_control        - Value to be written to PM1A control
   *              pm1b_control        - Value to be written to PM1B control
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Write the PM1 A/B control registers. These registers are
   *              different than than the PM1 A/B status and enable registers
   *              in that different values can be written to the A/B registers.
   *              Most notably, the SLP_TYP bits can be different, as per the
   *              values returned from the _Sx predefined methods.
   *
   ******************************************************************************/
  
  acpi_status acpi_hw_write_pm1_control(u32 pm1a_control, u32 pm1b_control)
  {
  	acpi_status status;
  
  	ACPI_FUNCTION_TRACE(hw_write_pm1_control);
  
  	status =
  	    acpi_hw_write(pm1a_control, &acpi_gbl_FADT.xpm1a_control_block);
  	if (ACPI_FAILURE(status)) {
  		return_ACPI_STATUS(status);
  	}
  
  	if (acpi_gbl_FADT.xpm1b_control_block.address) {
  		status =
  		    acpi_hw_write(pm1b_control,
  				  &acpi_gbl_FADT.xpm1b_control_block);
  	}
  	return_ACPI_STATUS(status);
  }
  
  /******************************************************************************
   *
   * FUNCTION:    acpi_hw_register_read
   *
   * PARAMETERS:  register_id         - ACPI Register ID
   *              return_value        - Where the register value is returned
   *
   * RETURN:      Status and the value read.
   *
   * DESCRIPTION: Read from the specified ACPI register
   *
   ******************************************************************************/
  acpi_status acpi_hw_register_read(u32 register_id, u32 *return_value)
  {
  	u32 value = 0;
  	acpi_status status;
  
  	ACPI_FUNCTION_TRACE(hw_register_read);
  
  	switch (register_id) {
  	case ACPI_REGISTER_PM1_STATUS:	/* PM1 A/B: 16-bit access each */
  
  		status = acpi_hw_read_multiple(&value,
  					       &acpi_gbl_xpm1a_status,
  					       &acpi_gbl_xpm1b_status);
  		break;
  
  	case ACPI_REGISTER_PM1_ENABLE:	/* PM1 A/B: 16-bit access each */
  
  		status = acpi_hw_read_multiple(&value,
  					       &acpi_gbl_xpm1a_enable,
  					       &acpi_gbl_xpm1b_enable);
  		break;
  
  	case ACPI_REGISTER_PM1_CONTROL:	/* PM1 A/B: 16-bit access each */
  
  		status = acpi_hw_read_multiple(&value,
  					       &acpi_gbl_FADT.
  					       xpm1a_control_block,
  					       &acpi_gbl_FADT.
  					       xpm1b_control_block);
  
  		/*
  		 * Zero the write-only bits. From the ACPI specification, "Hardware
  		 * Write-Only Bits": "Upon reads to registers with write-only bits,
  		 * software masks out all write-only bits."
  		 */
  		value &= ~ACPI_PM1_CONTROL_WRITEONLY_BITS;
  		break;
  
  	case ACPI_REGISTER_PM2_CONTROL:	/* 8-bit access */
  
  		status =
  		    acpi_hw_read(&value, &acpi_gbl_FADT.xpm2_control_block);
  		break;
  
  	case ACPI_REGISTER_PM_TIMER:	/* 32-bit access */
  
  		status = acpi_hw_read(&value, &acpi_gbl_FADT.xpm_timer_block);
  		break;
  
  	case ACPI_REGISTER_SMI_COMMAND_BLOCK:	/* 8-bit access */
  
  		status =
  		    acpi_hw_read_port(acpi_gbl_FADT.smi_command, &value, 8);
  		break;
  
  	default:
  
  		ACPI_ERROR((AE_INFO, "Unknown Register ID: 0x%X", register_id));
  		status = AE_BAD_PARAMETER;
  		break;
  	}
  
  	if (ACPI_SUCCESS(status)) {
  		*return_value = value;
  	}
  
  	return_ACPI_STATUS(status);
  }
  
  /******************************************************************************
   *
   * FUNCTION:    acpi_hw_register_write
   *
   * PARAMETERS:  register_id         - ACPI Register ID
   *              value               - The value to write
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Write to the specified ACPI register
   *
   * NOTE: In accordance with the ACPI specification, this function automatically
   * preserves the value of the following bits, meaning that these bits cannot be
   * changed via this interface:
   *
   * PM1_CONTROL[0] = SCI_EN
   * PM1_CONTROL[9]
   * PM1_STATUS[11]
   *
   * ACPI References:
   * 1) Hardware Ignored Bits: When software writes to a register with ignored
   *      bit fields, it preserves the ignored bit fields
   * 2) SCI_EN: OSPM always preserves this bit position
   *
   ******************************************************************************/
  
  acpi_status acpi_hw_register_write(u32 register_id, u32 value)
  {
  	acpi_status status;
  	u32 read_value;
  
  	ACPI_FUNCTION_TRACE(hw_register_write);
  
  	switch (register_id) {
  	case ACPI_REGISTER_PM1_STATUS:	/* PM1 A/B: 16-bit access each */
  		/*
  		 * Handle the "ignored" bit in PM1 Status. According to the ACPI
  		 * specification, ignored bits are to be preserved when writing.
  		 * Normally, this would mean a read/modify/write sequence. However,
  		 * preserving a bit in the status register is different. Writing a
  		 * one clears the status, and writing a zero preserves the status.
  		 * Therefore, we must always write zero to the ignored bit.
  		 *
  		 * This behavior is clarified in the ACPI 4.0 specification.
  		 */
  		value &= ~ACPI_PM1_STATUS_PRESERVED_BITS;
  
  		status = acpi_hw_write_multiple(value,
  						&acpi_gbl_xpm1a_status,
  						&acpi_gbl_xpm1b_status);
  		break;
  
  	case ACPI_REGISTER_PM1_ENABLE:	/* PM1 A/B: 16-bit access each */
  
  		status = acpi_hw_write_multiple(value,
  						&acpi_gbl_xpm1a_enable,
  						&acpi_gbl_xpm1b_enable);
  		break;
  
  	case ACPI_REGISTER_PM1_CONTROL:	/* PM1 A/B: 16-bit access each */
  		/*
  		 * Perform a read first to preserve certain bits (per ACPI spec)
  		 * Note: This includes SCI_EN, we never want to change this bit
  		 */
  		status = acpi_hw_read_multiple(&read_value,
  					       &acpi_gbl_FADT.
  					       xpm1a_control_block,
  					       &acpi_gbl_FADT.
  					       xpm1b_control_block);
  		if (ACPI_FAILURE(status)) {
  			goto exit;
  		}
  
  		/* Insert the bits to be preserved */
  
  		ACPI_INSERT_BITS(value, ACPI_PM1_CONTROL_PRESERVED_BITS,
  				 read_value);
  
  		/* Now we can write the data */
  
  		status = acpi_hw_write_multiple(value,
  						&acpi_gbl_FADT.
  						xpm1a_control_block,
  						&acpi_gbl_FADT.
  						xpm1b_control_block);
  		break;
  
  	case ACPI_REGISTER_PM2_CONTROL:	/* 8-bit access */
  		/*
  		 * For control registers, all reserved bits must be preserved,
  		 * as per the ACPI spec.
  		 */
  		status =
  		    acpi_hw_read(&read_value,
  				 &acpi_gbl_FADT.xpm2_control_block);
  		if (ACPI_FAILURE(status)) {
  			goto exit;
  		}
  
  		/* Insert the bits to be preserved */
  
  		ACPI_INSERT_BITS(value, ACPI_PM2_CONTROL_PRESERVED_BITS,
  				 read_value);
  
  		status =
  		    acpi_hw_write(value, &acpi_gbl_FADT.xpm2_control_block);
  		break;
  
  	case ACPI_REGISTER_PM_TIMER:	/* 32-bit access */
  
  		status = acpi_hw_write(value, &acpi_gbl_FADT.xpm_timer_block);
  		break;
  
  	case ACPI_REGISTER_SMI_COMMAND_BLOCK:	/* 8-bit access */
  
  		/* SMI_CMD is currently always in IO space */
  
  		status =
  		    acpi_hw_write_port(acpi_gbl_FADT.smi_command, value, 8);
  		break;
  
  	default:
  
  		ACPI_ERROR((AE_INFO, "Unknown Register ID: 0x%X", register_id));
  		status = AE_BAD_PARAMETER;
  		break;
  	}
  
  exit:
  	return_ACPI_STATUS(status);
  }
  
  /******************************************************************************
   *
   * FUNCTION:    acpi_hw_read_multiple
   *
   * PARAMETERS:  value               - Where the register value is returned
   *              register_a           - First ACPI register (required)
   *              register_b           - Second ACPI register (optional)
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Read from the specified two-part ACPI register (such as PM1 A/B)
   *
   ******************************************************************************/
  
  static acpi_status
  acpi_hw_read_multiple(u32 *value,
  		      struct acpi_generic_address *register_a,
  		      struct acpi_generic_address *register_b)
  {
  	u32 value_a = 0;
  	u32 value_b = 0;
  	acpi_status status;
  
  	/* The first register is always required */
  
  	status = acpi_hw_read(&value_a, register_a);
  	if (ACPI_FAILURE(status)) {
  		return (status);
  	}
  
  	/* Second register is optional */
  
  	if (register_b->address) {
  		status = acpi_hw_read(&value_b, register_b);
  		if (ACPI_FAILURE(status)) {
  			return (status);
  		}
  	}
  
  	/*
  	 * OR the two return values together. No shifting or masking is necessary,
  	 * because of how the PM1 registers are defined in the ACPI specification:
  	 *
  	 * "Although the bits can be split between the two register blocks (each
  	 * register block has a unique pointer within the FADT), the bit positions
  	 * are maintained. The register block with unimplemented bits (that is,
  	 * those implemented in the other register block) always returns zeros,
  	 * and writes have no side effects"
  	 */
  	*value = (value_a | value_b);
  	return (AE_OK);
  }
  
  /******************************************************************************
   *
   * FUNCTION:    acpi_hw_write_multiple
   *
   * PARAMETERS:  value               - The value to write
   *              register_a           - First ACPI register (required)
   *              register_b           - Second ACPI register (optional)
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Write to the specified two-part ACPI register (such as PM1 A/B)
   *
   ******************************************************************************/
  
  static acpi_status
  acpi_hw_write_multiple(u32 value,
  		       struct acpi_generic_address *register_a,
  		       struct acpi_generic_address *register_b)
  {
  	acpi_status status;
  
  	/* The first register is always required */
  
  	status = acpi_hw_write(value, register_a);
  	if (ACPI_FAILURE(status)) {
  		return (status);
  	}
  
  	/*
  	 * Second register is optional
  	 *
  	 * No bit shifting or clearing is necessary, because of how the PM1
  	 * registers are defined in the ACPI specification:
  	 *
  	 * "Although the bits can be split between the two register blocks (each
  	 * register block has a unique pointer within the FADT), the bit positions
  	 * are maintained. The register block with unimplemented bits (that is,
  	 * those implemented in the other register block) always returns zeros,
  	 * and writes have no side effects"
  	 */
  	if (register_b->address) {
  		status = acpi_hw_write(value, register_b);
  	}
  
  	return (status);
  }
  
  #endif				/* !ACPI_REDUCED_HARDWARE */