soc/amd/common/block/data_fabric: add warning about broadcast reads
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: If1b65ae3dd2b5c8fe7bc29a267d108e4d3a3e567
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50883
Reviewed-by: Jason Glenesk <jason.glenesk@gmail.com>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/common/block/data_fabric/data_fabric_helper.c b/src/soc/amd/common/block/data_fabric/data_fabric_helper.c
index 27fc03d..abb4ba8 100644
--- a/src/soc/amd/common/block/data_fabric/data_fabric_helper.c
+++ b/src/soc/amd/common/block/data_fabric/data_fabric_helper.c
@@ -23,6 +23,8 @@
uint32_t data_fabric_read32(uint8_t function, uint16_t reg, uint8_t instance_id)
{
+ /* Broadcast reads might return unexpected results when a register has different
+ contents in the different instances. */
if (instance_id == BROADCAST_FABRIC_ID)
return data_fabric_broadcast_read32(function, reg);