Xeon-SP boards: Factor out OCP VPD `get_cxl_mode()` impl

There's two copies of the `get_cxl_mode()` function to map the OCP VPD
value to the values expected by platform code. As this is unnecessary,
have a single copy of this function in the OCP VPD driver code. As the
`get_cxl_mode()` function is Xeon-SP only, keep it in a separate file.

This change simplifies things for boards using OCP VPD for CXL and has
no impact for boards *not* using OCP VPD:

- Boards not using OCP VPD can still define get_cxl_mode() in mainboard
  code as needed, just like they were able to do before.
- Boards using OCP VPD but without CXL (`SOC_INTEL_HAS_CXL` is not
  enabled), this code won't get compiled in at all (see `Makefile.mk`).
- Boards using OCP VPD and CXL will automatically make use of this
  `get_cxl_mode()` definition, which should be the same for all boards.

It is possible that this may need to be expanded/adapted in the future,
which is easy to handle in a follow-up commit when the need arises.

TEST=Build and boot on intel/archercity CRB

Change-Id: I935c4eb5b2392e2d0dc01b9f66d46c79b8141ea7
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82224
Reviewed-by: Shuo Liu <shuo.liu@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>

2 files changed, 26 insertions, 2 deletions

diff --git a/src/drivers/ocp/vpd/Makefile.mk b/src/drivers/ocp/vpd/Makefile.mk
index 1cdc63b524..29aad05374 100644
--- a/src/drivers/ocp/vpd/Makefile.mk
+++ b/src/drivers/ocp/vpd/Makefile.mk
@@ -1,7 +1,14 @@
 ## SPDX-License-Identifier: GPL-2.0-only
 
-romstage-$(CONFIG_OCP_VPD) += vpd_util.c
-ramstage-$(CONFIG_OCP_VPD) += vpd_util.c
+ifeq ($(CONFIG_OCP_VPD),y)
+romstage-y += vpd_util.c
+ramstage-y += vpd_util.c
+ifeq ($(CONFIG_XEON_SP_COMMON_BASE),y)
+romstage-$(CONFIG_SOC_INTEL_HAS_CXL) += xeonsp_cxl.c
+ramstage-$(CONFIG_SOC_INTEL_HAS_CXL) += xeonsp_cxl.c
+endif
+endif
+
 ramstage-$(CONFIG_LINUXPAYLOAD_CMDLINE_VPD_OVERWRITE) += vpd_cmdline.c
 ifeq ($(CONFIG_VPD),y)
 all-$(CONFIG_CONSOLE_OVERRIDE_LOGLEVEL) += loglevel_vpd.c
diff --git a/src/drivers/ocp/vpd/xeonsp_cxl.c b/src/drivers/ocp/vpd/xeonsp_cxl.c
new file mode 100644
index 0000000000..92a8eba0f8
--- /dev/null
+++ b/src/drivers/ocp/vpd/xeonsp_cxl.c
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <drivers/ocp/include/vpd.h>
+#include <soc/config.h>
+
+enum xeonsp_cxl_mode get_cxl_mode(void)
+{
+	int ocp_cxl_mode = get_cxl_mode_from_vpd();
+	switch (ocp_cxl_mode) {
+	case CXL_SYSTEM_MEMORY:
+		return XEONSP_CXL_SYS_MEM;
+	case CXL_SPM:
+		return XEONSP_CXL_SP_MEM;
+	default:
+		return XEONSP_CXL_DISABLED;
+	}
+}