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Commit 3e71a87d authored by Alexey Starikovskiy's avatar Alexey Starikovskiy Committed by Len Brown
Browse files

ACPI: EC: Do the byte access with a fast path 

Specification allows only byte access for EC region, so
make it separate from bug-compatible multi-byte access.
Also do not allow return of garbage in supplied *value.

Reference: http://bugzilla.kernel.org/show_bug.cgi?id=9341



Signed-off-by: default avatarAlexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent fd0b45df

drivers/acpi/ec.c

+11 −4
Original line number Diff line number Diff line
@@ -563,7 +563,7 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address, 
		      void *handler_context, void *region_context)

{

	struct acpi_ec *ec = handler_context;

	int result = 0, i = 0;

	int result = 0, i;

	u8 temp = 0;



	if ((address > 0xFF) || !value || !handler_context)
@@ -575,7 +575,16 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address, 
	if (bits != 8 && acpi_strict)

		return AE_BAD_PARAMETER;



	while (bits - i > 0) {

	if (function == ACPI_READ) {

		result = acpi_ec_read(ec, address, &temp);

		*value = temp;

	} else {

		temp = 0xff & (*value);

		result = acpi_ec_write(ec, address, temp);

	}



	for (i = 8; unlikely(bits - i > 0); i += 8) {

		++address;

		if (function == ACPI_READ) {

			result = acpi_ec_read(ec, address, &temp);

			(*value) |= ((acpi_integer)temp) << i;
@@ -583,8 +592,6 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address, 
			temp = 0xff & ((*value) >> i);

			result = acpi_ec_write(ec, address, temp);

		}

		i += 8;

		++address;

	}



	switch (result) {