ACPI: EC: Allow multibyte access to EC

commit dadf28a10c3eb29421837a2e413ab869ebd upstream

http://bugzilla.kernel.org/show_bug.cgi?id=14667

[bwh: Backport to 2.6.32; same applies to 2.6.33]

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 21 insertions, 26 deletions

diff --git a/drivers/acpi/acpica/exprep.c b/drivers/acpi/acpica/exprep.c
index 52fec07064f0..c02d543a2601 100644
--- a/drivers/acpi/acpica/exprep.c
+++ b/drivers/acpi/acpica/exprep.c
@@ -468,6 +468,18 @@ acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
 
                 acpi_ut_add_reference(obj_desc->field.region_obj);
 
+                /* allow full data read from EC address space */
+                if (obj_desc->field.region_obj->region.space_id ==
+                        ACPI_ADR_SPACE_EC) {
+                        if (obj_desc->common_field.bit_length > 8)
+                                obj_desc->common_field.access_bit_width =
+                                ACPI_ROUND_UP(obj_desc->common_field.
+                                                        bit_length, 8);
+                                obj_desc->common_field.access_byte_width =
+                                ACPI_DIV_8(obj_desc->common_field.
+                                                        access_bit_width);
+                }
+
                 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                                   "RegionField: BitOff %X, Off %X, Gran %X, Region %p\n",
                                   obj_desc->field.start_field_bit_offset,
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index d6471bb6852f..fc67d1175a56 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -589,12 +589,12 @@ static u32 acpi_ec_gpe_handler(void *data)
 
 static acpi_status
 acpi_ec_space_handler(u32 function, acpi_physical_address address,
-                      u32 bits, acpi_integer *value,
+                      u32 bits, acpi_integer *value64,
                       void *handler_context, void *region_context)
 {
         struct acpi_ec *ec = handler_context;
-        int result = 0, i;
-        u8 temp = 0;
+        int result = 0, i, bytes = bits / 8;
+        u8 *value = (u8 *)value64;
 
         if ((address > 0xFF) || !value || !handler_context)
                 return AE_BAD_PARAMETER;
@@ -602,32 +602,15 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address,
         if (function != ACPI_READ && function != ACPI_WRITE)
                 return AE_BAD_PARAMETER;
 
-        if (bits != 8 && acpi_strict)
-                return AE_BAD_PARAMETER;
-
-        if (EC_FLAGS_MSI)
+        if (EC_FLAGS_MSI || bits > 8)
                 acpi_ec_burst_enable(ec);
 
-        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;
-                } else {
-                        temp = 0xff & ((*value) >> i);
-                        result = acpi_ec_write(ec, address, temp);
-                }
-        }
+        for (i = 0; i < bytes; ++i, ++address, ++value)
+                result = (function == ACPI_READ) ?
+                        acpi_ec_read(ec, address, value) :
+                        acpi_ec_write(ec, address, *value);
 
-        if (EC_FLAGS_MSI)
+        if (EC_FLAGS_MSI || bits > 8)
                 acpi_ec_burst_disable(ec);
 
         switch (result) {