On 05/05/2016 12:58 AM, Lv Zheng wrote: > 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@xxxxxxxxxxx>, fixed by Lv Zheng <lv.zheng@xxxxxxxxx>, tested > by Jung-uk Kim <jkim@xxxxxxxxxxx>. > > Link: https://github.com/acpica/acpica/commit/c49a751b > Reported-by: John Baldwin <jhb@xxxxxxxxxxx> > Tested-by Jung-uk Kim <jkim@xxxxxxxxxxx>. > Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx> > Signed-off-by: Bob Moore <robert.moore@xxxxxxxxx> > --- > drivers/acpi/acpica/hwregs.c | 49 ++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 47 insertions(+), 2 deletions(-) > > diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c > index 035fb52..892e677 100644 > --- a/drivers/acpi/acpica/hwregs.c > +++ b/drivers/acpi/acpica/hwregs.c > @@ -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, > @@ -65,6 +69,48 @@ acpi_hw_write_multiple(u32 value, > > /****************************************************************************** > * > + * 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, ®->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); This (together with "... Add access_width/bit_offset support in acpi_hw_write") breaks Xen guests using older QEMU which doesn't support 4-byte IO accesses. Why not return "reg->bit_width?:max_bit_width" ? This will preserve original behavior. -boris > + } else { > + return (max_bit_width); > + } > + } > + } else { > + return (1 << (reg->access_width + 2)); > + } > +} > + > +/****************************************************************************** > + * > * FUNCTION: acpi_hw_validate_register > * > * PARAMETERS: reg - GAS register structure > @@ -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) { -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
