refactor(fvp): nv ctr addr static helper function

Adding a static helper function plat_get_nv_ctr_addr() to be used by
both plat_set_nv_ctr() and plat_get_nv_ctr() to return the
non-volatile counter address stored in the platform.

Change-Id: I5124c19e4537bb369724aa0160cc55a3cb1ab7eb
Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>

plat/arm/board/fvp/fvp_trusted_boot.c

@@ -36,35 +36,52 @@ int plat_get_rotpk_info(void *cookie, void **key_ptr, unsigned int *key_len,
 }
 
 /*
- * Store a new non-volatile counter value.
- *
- * On some FVP versions, the non-volatile counters are read-only so this
- * function will always fail.
+ * Return the non-volatile counter address stored in the platform. The cookie
+ * will contain the OID of the counter in the certificate.
  *
  * Return: 0 = success, Otherwise = error
  */
-int plat_set_nv_ctr(void *cookie, unsigned int nv_ctr)
+static int plat_get_nv_ctr_addr(void *cookie, uintptr_t *nv_ctr_addr)
 {
-	const char *oid;
-	uintptr_t nv_ctr_addr;
-
-	assert(cookie != NULL);
+	const char *oid = (const char *)cookie;
 
-	oid = (const char *)cookie;
 	if (strcmp(oid, TRUSTED_FW_NVCOUNTER_OID) == 0) {
-		nv_ctr_addr = FCONF_GET_PROPERTY(cot, nv_cntr_addr,
+		*nv_ctr_addr = FCONF_GET_PROPERTY(cot, nv_cntr_addr,
 						TRUSTED_NV_CTR_ID);
 	} else if (strcmp(oid, NON_TRUSTED_FW_NVCOUNTER_OID) == 0) {
-		nv_ctr_addr = FCONF_GET_PROPERTY(cot, nv_cntr_addr,
+		*nv_ctr_addr = FCONF_GET_PROPERTY(cot, nv_cntr_addr,
 						NON_TRUSTED_NV_CTR_ID);
 	} else if (strcmp(oid, CCA_FW_NVCOUNTER_OID) == 0) {
 		/* FVP does not support the CCA NV Counter so use the Trusted NV */
-		nv_ctr_addr = FCONF_GET_PROPERTY(cot, nv_cntr_addr,
+		*nv_ctr_addr = FCONF_GET_PROPERTY(cot, nv_cntr_addr,
 						TRUSTED_NV_CTR_ID);
 	} else {
 		return 1;
 	}
 
+	return 0;
+}
+
+/*
+ * Store a new non-volatile counter value.
+ *
+ * On some FVP versions, the non-volatile counters are read-only so this
+ * function will always fail.
+ *
+ * Return: 0 = success, Otherwise = error
+ */
+int plat_set_nv_ctr(void *cookie, unsigned int nv_ctr)
+{
+	uintptr_t nv_ctr_addr;
+	int rc;
+
+	assert(cookie != NULL);
+
+	rc = plat_get_nv_ctr_addr(cookie, &nv_ctr_addr);
+	if (rc != 0) {
+		return rc;
+	}
+
 	mmio_write_32(nv_ctr_addr, nv_ctr);
 
 	/*
@@ -82,28 +99,18 @@ int plat_set_nv_ctr(void *cookie, unsigned int nv_ctr)
  */
 int plat_get_nv_ctr(void *cookie, unsigned int *nv_ctr)
 {
-	const char *oid;
-	uint32_t *nv_ctr_addr;
+	uintptr_t nv_ctr_addr;
+	int rc;
 
 	assert(cookie != NULL);
 	assert(nv_ctr != NULL);
 
-	oid = (const char *)cookie;
-	if (strcmp(oid, TRUSTED_FW_NVCOUNTER_OID) == 0) {
-		nv_ctr_addr = (uint32_t *)FCONF_GET_PROPERTY(cot, nv_cntr_addr,
-							TRUSTED_NV_CTR_ID);
-	} else if (strcmp(oid, NON_TRUSTED_FW_NVCOUNTER_OID) == 0) {
-		nv_ctr_addr = (uint32_t *)FCONF_GET_PROPERTY(cot, nv_cntr_addr,
-							NON_TRUSTED_NV_CTR_ID);
-	} else if (strcmp(oid, CCA_FW_NVCOUNTER_OID) == 0) {
-		/* FVP does not support the CCA NV Counter so use the Trusted NV */
-		nv_ctr_addr = (uint32_t *)FCONF_GET_PROPERTY(cot, nv_cntr_addr,
-							TRUSTED_NV_CTR_ID);
-	} else {
-		return 1;
+	rc = plat_get_nv_ctr_addr(cookie, &nv_ctr_addr);
+	if (rc != 0) {
+		return rc;
 	}
 
-	*nv_ctr = (unsigned int)(*nv_ctr_addr);
+	*nv_ctr = *((unsigned int *)nv_ctr_addr);
 
 	return 0;
 }