feat(versal2): is OCM configured as coherent

Warn users about disabled OCM coherency which is not enabled by
default in designs. If it is not enabled and TF-A is running out
of OCM,TF-A won't work properly.
This check is done only in Debug mode and isolation disabled.

Change-Id: I7661e0183503b71085c57fa35014341d14522203
Signed-off-by: Saivardhan Thatikonda <saivardhan.thatikonda@amd.com>
diff --git a/plat/amd/versal2/plat_ocm_coherency.c b/plat/amd/versal2/plat_ocm_coherency.c
new file mode 100644
index 0000000..872ee23
--- /dev/null
+++ b/plat/amd/versal2/plat_ocm_coherency.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2025, Advanced Micro Devices, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include <common/debug.h>
+#include <lib/mmio.h>
+
+#include <plat_ocm_coherency.h>
+#include <platform_def.h>
+
+/*
+ * Register non hash mem regions addresses
+ */
+#define POR_RNSAM_NODE_INFO_U_RNFBESAM_NID12    U(0xF8168000)
+#define NON_HASH_MEM_REGION_REG0        U(POR_RNSAM_NODE_INFO_U_RNFBESAM_NID12 + 0xC08)
+#define NON_HASH_MEM_REGION_REG1        U(POR_RNSAM_NODE_INFO_U_RNFBESAM_NID12 + 0xC0C)
+#define NON_HASH_MEM_REGION_REG2        U(POR_RNSAM_NODE_INFO_U_RNFBESAM_NID12 + 0xC10)
+#define NON_HASH_MEM_REGION_REG3        U(POR_RNSAM_NODE_INFO_U_RNFBESAM_NID12 + 0xC14)
+#define NON_HASH_MEM_REGION_REG4        U(POR_RNSAM_NODE_INFO_U_RNFBESAM_NID12 + 0xC18)
+#define NON_HASH_MEM_REGION_REG5        U(POR_RNSAM_NODE_INFO_U_RNFBESAM_NID12 + 0xC1C)
+#define NON_HASH_MEM_REGION_REG6        U(POR_RNSAM_NODE_INFO_U_RNFBESAM_NID12 + 0xC20)
+#define NON_HASH_MEM_REGION_REG7        U(POR_RNSAM_NODE_INFO_U_RNFBESAM_NID12 + 0xC24)
+
+#define REGION_BASE_ADDR_VALUE	U(0x2E)
+#define REGION_BASE_ADDR_SHIFT	9
+
+#define REGION_BASE_ADDRESS_MASK	GENMASK(30, REGION_BASE_ADDR_SHIFT)
+#define REGION_VALID_BIT		BIT(0)
+
+/*
+ * verify the register configured as non-hashed
+ */
+#define IS_NON_HASHED_REGION(reg) \
+((FIELD_GET(REGION_BASE_ADDRESS_MASK, mmio_read_32(reg)) == REGION_BASE_ADDR_VALUE) && \
+						(mmio_read_32(reg) & REGION_VALID_BIT))
+
+/*
+ * Splitter registers
+ */
+#define FPX_SPLITTER_0          U(0xECC20000)
+#define FPX_SPLITTER_1          U(0xECD20000)
+#define FPX_SPLITTER_2          U(0xECE20000)
+#define FPX_SPLITTER_3          U(0xECF20000)
+#define OCM_ADDR_DIST_MODE      BIT(16)
+
+#define OCM_COHERENT	0
+#define OCM_NOT_COHERENT	1
+#define TFA_NOT_IN_OCM	2
+
+/*
+ * Function that verifies the OCM is coherent or not with the following checks:
+ * verify that OCM is in non hashed region or not if not then verify
+ * OCM_ADDR_DIST_MODE bit in splitter registers is set.
+ */
+int32_t check_ocm_coherency(void)
+{
+	int32_t status = OCM_COHERENT;
+	/* isolation should be disabled in order to read these registers */
+	if ((IS_NON_HASHED_REGION(NON_HASH_MEM_REGION_REG0) ||
+	     IS_NON_HASHED_REGION(NON_HASH_MEM_REGION_REG1) ||
+	     IS_NON_HASHED_REGION(NON_HASH_MEM_REGION_REG2) ||
+	     IS_NON_HASHED_REGION(NON_HASH_MEM_REGION_REG3) ||
+	     IS_NON_HASHED_REGION(NON_HASH_MEM_REGION_REG4) ||
+	     IS_NON_HASHED_REGION(NON_HASH_MEM_REGION_REG5) ||
+	     IS_NON_HASHED_REGION(NON_HASH_MEM_REGION_REG6) ||
+	     IS_NON_HASHED_REGION(NON_HASH_MEM_REGION_REG7))) {
+		WARN("OCM is not configured as coherent\n");
+		status = OCM_NOT_COHERENT;
+	} else {
+		/* verify OCM_ADDR_DIST_MODE bit in splitter registers is set */
+		if (!((mmio_read_32(FPX_SPLITTER_0) & OCM_ADDR_DIST_MODE) &&
+		      (mmio_read_32(FPX_SPLITTER_1) & OCM_ADDR_DIST_MODE) &&
+		      (mmio_read_32(FPX_SPLITTER_2) & OCM_ADDR_DIST_MODE) &&
+		      (mmio_read_32(FPX_SPLITTER_3) & OCM_ADDR_DIST_MODE))) {
+			WARN("OCM is not configured as coherent\n");
+			status = OCM_NOT_COHERENT;
+		}
+	}
+	return status;
+}
+