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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: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Alexey Starikovskiy 2008-01-11 02:42:51 +03:00 committed by Len Brown
parent fd0b45dfd1
commit 3e71a87d03

View File

@ -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) {