ec/google/wilco: Set minimum UCSI_ACPI region length
IMD provides support for small and large allocations. Region IMD Small memory is 1 KB
with 32 Bytes alignment, this region holds smaller entries without having to reserve a
whole 4 KB page. Remaining space is assigned to IMD Large to hold various regions with
4 KB alignment.
The UCSI kernel (kernel version 4.19) driver maps the UCSI_ACPI memory as not cached.
Cache mapping is set on page boundaries and all IMD Small is within the same page.
If another driver maps the memory as write-back before the UCSI driver is loaded then
the UCSI driver will fail to map the memory as not cached.
Placing UCSI_ACPI in IMD Large region will prevent this mapping issue since it will
now be located within its own page. This patch will force UCSI_ACPI region to be
located in IMD Large region.
BUG=b:144826008
Signed-off-by: Bernardo Perez Priego <bernardo.perez.priego@intel.com>
Change-Id: Id00e76dca240279773a95c8054831e05df390664
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38414
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-by: Mathew King <mathewk@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/ec/google/wilco/chip.c b/src/ec/google/wilco/chip.c
index 70e6124..b44cbd6 100644
--- a/src/ec/google/wilco/chip.c
+++ b/src/ec/google/wilco/chip.c
@@ -28,6 +28,11 @@
#include "chip.h"
/*
+ * Setting minimum length of UCSI_ACPI will ensure this region is placed out of IMD Small.
+ * Having this region out of IMD Small will prevent any memory mapping conflicts.
+ */
+#define UCSI_MIN_ALLOC_REGION_LEN CBMEM_SM_ROOT_SIZE
+/*
* The UCSI fields are defined in the UCSI specification at
* https://www.intel.com/content/www/us/en/io/universal-serial-bus/usb-type-c-ucsi-spec.html
* https://www.intel.com/content/www/us/en/io/universal-serial-bus/bios-implementation-of-ucsi.html
@@ -175,19 +180,22 @@
{
struct opregion opreg;
void *region_ptr;
+ size_t ucsi_alloc_region_len;
if (!dev->enabled)
return;
- region_ptr = cbmem_add(CBMEM_ID_ACPI_UCSI, ucsi_region_len);
+ ucsi_alloc_region_len = ucsi_region_len < UCSI_MIN_ALLOC_REGION_LEN ?
+ UCSI_MIN_ALLOC_REGION_LEN : ucsi_region_len;
+ region_ptr = cbmem_add(CBMEM_ID_ACPI_UCSI, ucsi_alloc_region_len);
if (!region_ptr)
return;
- memset(region_ptr, 0, ucsi_region_len);
+ memset(region_ptr, 0, ucsi_alloc_region_len);
opreg.name = "UCSM";
opreg.regionspace = SYSTEMMEMORY;
opreg.regionoffset = (uintptr_t)region_ptr;
- opreg.regionlen = ucsi_region_len;
+ opreg.regionlen = ucsi_alloc_region_len;
acpigen_write_scope(acpi_device_path_join(dev, "UCSI"));
acpigen_write_name("_CRS");