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authorAlexey Starikovskiy <astarikovskiy@suse.de>2008-01-11 02:42:51 +0300
committerLen Brown <len.brown@intel.com>2008-01-10 20:49:14 -0500
commit3e71a87d03055de0b8c8e42aba758ee6494af083 (patch)
treea1fb6be330f06e82a1565ccbdd37a9db260dc756 /drivers/acpi/ec.c
parentfd0b45dfd1858c6b49d06355a460bcf36d654c06 (diff)
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>
Diffstat (limited to 'drivers/acpi/ec.c')
-rw-r--r--drivers/acpi/ec.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index d411017f8c0..63862dfe347 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -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) {