diff options
| -rw-r--r-- | drivers/acpi/acpica/hwregs.c | 79 |
1 files changed, 57 insertions, 22 deletions
diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c index 2bc3425d3b6a..50b90707d755 100644 --- a/drivers/acpi/acpica/hwregs.c +++ b/drivers/acpi/acpica/hwregs.c @@ -52,7 +52,8 @@ ACPI_MODULE_NAME("hwregs") #if (!ACPI_REDUCED_HARDWARE) /* Local Prototypes */ static u8 -acpi_hw_get_access_bit_width(struct acpi_generic_address *reg, +acpi_hw_get_access_bit_width(u64 address, + struct acpi_generic_address *reg, u8 max_bit_width); static acpi_status @@ -71,7 +72,8 @@ acpi_hw_write_multiple(u32 value, * * FUNCTION: acpi_hw_get_access_bit_width * - * PARAMETERS: reg - GAS register structure + * PARAMETERS: address - GAS register address + * reg - GAS register structure * max_bit_width - Max bit_width supported (32 or 64) * * RETURN: Status @@ -81,27 +83,59 @@ acpi_hw_write_multiple(u32 value, ******************************************************************************/ static u8 -acpi_hw_get_access_bit_width(struct acpi_generic_address *reg, u8 max_bit_width) +acpi_hw_get_access_bit_width(u64 address, + struct acpi_generic_address *reg, u8 max_bit_width) { - if (!reg->access_width) { - if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) { - max_bit_width = 32; - } + u8 access_bit_width; - /* - * Detect old register descriptors where only the bit_width field - * makes senses. - */ - if (reg->bit_width < max_bit_width && - !reg->bit_offset && reg->bit_width && - ACPI_IS_POWER_OF_TWO(reg->bit_width) && - ACPI_IS_ALIGNED(reg->bit_width, 8)) { - return (reg->bit_width); - } - return (max_bit_width); + /* + * GAS format "register", used by FADT: + * 1. Detected if bit_offset is 0 and bit_width is 8/16/32/64; + * 2. access_size field is ignored and bit_width field is used for + * determining the boundary of the IO accesses. + * GAS format "region", used by APEI registers: + * 1. Detected if bit_offset is not 0 or bit_width is not 8/16/32/64; + * 2. access_size field is used for determining the boundary of the + * IO accesses; + * 3. bit_offset/bit_width fields are used to describe the "region". + * + * Note: This algorithm assumes that the "Address" fields should always + * contain aligned values. + */ + if (!reg->bit_offset && reg->bit_width && + ACPI_IS_POWER_OF_TWO(reg->bit_width) && + ACPI_IS_ALIGNED(reg->bit_width, 8)) { + access_bit_width = reg->bit_width; + } else if (reg->access_width) { + access_bit_width = (1 << (reg->access_width + 2)); } else { - return (1 << (reg->access_width + 2)); + access_bit_width = + ACPI_ROUND_UP_POWER_OF_TWO_8(reg->bit_offset + + reg->bit_width); + if (access_bit_width <= 8) { + access_bit_width = 8; + } else { + while (!ACPI_IS_ALIGNED(address, access_bit_width >> 3)) { + access_bit_width >>= 1; + } + } + } + + /* Maximum IO port access bit width is 32 */ + + if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) { + max_bit_width = 32; + } + + /* + * Return access width according to the requested maximum access bit width, + * as the caller should know the format of the register and may enforce + * a 32-bit accesses. + */ + if (access_bit_width < max_bit_width) { + return (access_bit_width); } + return (max_bit_width); } /****************************************************************************** @@ -163,7 +197,8 @@ acpi_hw_validate_register(struct acpi_generic_address *reg, /* Validate the bit_width, convert access_width into number of bits */ - access_width = acpi_hw_get_access_bit_width(reg, max_bit_width); + access_width = + acpi_hw_get_access_bit_width(*address, reg, max_bit_width); bit_width = ACPI_ROUND_UP(reg->bit_offset + reg->bit_width, access_width); if (max_bit_width < bit_width) { @@ -219,7 +254,7 @@ acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg) * into number of bits based */ *value = 0; - access_width = acpi_hw_get_access_bit_width(reg, 32); + access_width = acpi_hw_get_access_bit_width(address, reg, 32); bit_width = reg->bit_offset + reg->bit_width; bit_offset = reg->bit_offset; @@ -311,7 +346,7 @@ acpi_status acpi_hw_write(u32 value, struct acpi_generic_address *reg) /* Convert access_width into number of bits based */ - access_width = acpi_hw_get_access_bit_width(reg, 32); + access_width = acpi_hw_get_access_bit_width(address, reg, 32); bit_width = reg->bit_offset + reg->bit_width; bit_offset = reg->bit_offset; |