Commit b314a172 authored by Lv Zheng's avatar Lv Zheng Committed by Rafael J. Wysocki
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ACPICA: Hardware: Add optimized access bit width support 

ACPICA commit c49a751b4dae7baec1790748a2b4b6e8ab599f51

For Access Size = 0, it actually can use user expected access bit width.
This patch implements this.

Besides of the ACPICA upstream commit, this patch also includes a fix fixing
the issue reported by the FreeBSD community.

The old register descriptors are translated in acpi_tb_init_generic_address()
with access_width being filled with 0. This breaks code in
acpi_hw_get_access_bit_width() when the registers are 16-bit IO ports and their
bit_width fields are filled with 16. The rapid fix is meant to make code
written for acpi_hw_get_access_bit_width() regression safer before the issue is
correctly fixed from acpi_tb_init_generic_address(). Reported by
John Baldwin <jhb@freebsd.org>, fixed by Lv Zheng <lv.zheng@intel.com>, tested
by Jung-uk Kim <jkim@freebsd.org>.

Link: https://github.com/acpica/acpica/commit/c49a751b


Reported-by: default avatarJohn Baldwin <jhb@freebsd.org>
Tested-by Jung-uk Kim <jkim@freebsd.org>.
Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent e35d7502

drivers/acpi/acpica/hwregs.c

+47 −2
Original line number Diff line number Diff line
@@ -51,6 +51,10 @@ ACPI_MODULE_NAME("hwregs") 


#if (!ACPI_REDUCED_HARDWARE)

/* Local Prototypes */

static u8

acpi_hw_get_access_bit_width(struct acpi_generic_address *reg,

			     u8 max_bit_width);



static acpi_status

acpi_hw_read_multiple(u32 *value,

		      struct acpi_generic_address *register_a,
@@ -63,6 +67,48 @@ acpi_hw_write_multiple(u32 value, 


#endif				/* !ACPI_REDUCED_HARDWARE */



/******************************************************************************

 *

 * FUNCTION:    acpi_hw_get_access_bit_width

 *

 * PARAMETERS:  reg                 - GAS register structure

 *              max_bit_width       - Max bit_width supported (32 or 64)

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Obtain optimal access bit width

 *

 ******************************************************************************/



static u8

acpi_hw_get_access_bit_width(struct acpi_generic_address *reg, u8 max_bit_width)

{

	u64 address;



	if (!reg->access_width) {

		/*

		 * Detect old register descriptors where only the bit_width field

		 * makes senses. The target address is copied to handle possible

		 * alignment issues.

		 */

		ACPI_MOVE_64_TO_64(&address, &reg->address);

		if (!reg->bit_offset && reg->bit_width &&

		    ACPI_IS_POWER_OF_TWO(reg->bit_width) &&

		    ACPI_IS_ALIGNED(reg->bit_width, 8) &&

		    ACPI_IS_ALIGNED(address, reg->bit_width)) {

			return (reg->bit_width);

		} else {

			if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {

				return (32);

			} else {

				return (max_bit_width);

			}

		}

	} else {

		return (1 << (reg->access_width + 2));

	}

}



/******************************************************************************

 *

 * FUNCTION:    acpi_hw_validate_register
@@ -122,8 +168,7 @@ acpi_hw_validate_register(struct acpi_generic_address *reg, 


	/* Validate the bit_width, convert access_width into number of bits */



	access_width = reg->access_width ? reg->access_width : 1;

	access_width = 1 << (access_width + 2);

	access_width = acpi_hw_get_access_bit_width(reg, max_bit_width);

	bit_width =

	    ACPI_ROUND_UP(reg->bit_offset + reg->bit_width, access_width);

	if (max_bit_width < bit_width) {

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