bdb: Add nvmrw_get and nvmrw_set

These internal APIs are used to get and set values in NVM-RW variables.

BUG=chrome-os-partner:51907
BRANCH=tot
TEST=make runtests

Change-Id: Ibae1836cb569fe89dd2c8249f76c66b78b1c2cf4
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/356691
Reviewed-by: Randall Spangler <rspangler@chromium.org>

2 files changed, 118 insertions, 0 deletions

diff --git a/firmware/bdb/nvm.c b/firmware/bdb/nvm.c
index a7c56b0b..9c40ea55 100644
--- a/firmware/bdb/nvm.c
+++ b/firmware/bdb/nvm.c
@@ -265,3 +265,82 @@ int vba_update_buc(struct vba_context *ctx, uint8_t *new_buc)
 
 	return BDB_SUCCESS;
 }
+
+int nvmrw_get(struct vba_context *ctx, enum nvmrw_var var, uint32_t *val)
+{
+	struct nvmrw *nvm = &ctx->nvmrw;
+
+	/* No init or verify so that this can be called from futility.
+	 * Callers are responsible for init and verify. */
+
+	switch (var) {
+	case NVMRW_VAR_UPDATE_COUNT:
+		*val = nvm->update_count;
+		break;
+	case NVMRW_VAR_MIN_KERNEL_DATA_KEY_VERSION:
+		*val = nvm->min_kernel_data_key_version;
+		break;
+	case NVMRW_VAR_MIN_KERNEL_VERSION:
+		*val = nvm->min_kernel_version;
+		break;
+	case NVMRW_VAR_BUC_TYPE:
+		*val = nvm->buc_type;
+		break;
+	case NVMRW_VAR_FLAG_BUC_PRESENT:
+		*val = nvm->flags & NVM_RW_FLAG_BUC_PRESENT;
+		break;
+	case NVMRW_VAR_FLAG_DFM_DISABLE:
+		*val = nvm->flags & NVM_RW_FLAG_DFM_DISABLE;
+		break;
+	case NVMRW_VAR_FLAG_DOSM:
+		*val = nvm->flags & NVM_RW_FLAG_DOSM;
+		break;
+	default:
+		return BDB_ERROR_NVM_INVALID_PARAMETER;
+	}
+
+	return BDB_SUCCESS;
+}
+
+#define MAX_8BIT_UINT ((((uint64_t)1) << 8) - 1)
+
+int nvmrw_set(struct vba_context *ctx, enum nvmrw_var var, uint32_t val)
+{
+	struct nvmrw *nvm = &ctx->nvmrw;
+
+	/* No init or verify so that this can be called from futility.
+	 * Callers are responsible for init and verify. */
+
+	switch (var) {
+	case NVMRW_VAR_UPDATE_COUNT:
+		nvm->update_count = val;
+		break;
+	case NVMRW_VAR_MIN_KERNEL_DATA_KEY_VERSION:
+		nvm->min_kernel_data_key_version = val;
+		break;
+	case NVMRW_VAR_MIN_KERNEL_VERSION:
+		nvm->min_kernel_version = val;
+		break;
+	case NVMRW_VAR_BUC_TYPE:
+		if (val > MAX_8BIT_UINT)
+			return BDB_ERROR_NVM_INVALID_PARAMETER;
+		nvm->buc_type = val;
+		break;
+	case NVMRW_VAR_FLAG_BUC_PRESENT:
+		nvm->flags &= ~NVM_RW_FLAG_BUC_PRESENT;
+		nvm->flags |= val ? NVM_RW_FLAG_BUC_PRESENT : 0;
+		break;
+	case NVMRW_VAR_FLAG_DFM_DISABLE:
+		nvm->flags &= ~NVM_RW_FLAG_DFM_DISABLE;
+		nvm->flags |= val ? NVM_RW_FLAG_DFM_DISABLE : 0;
+		break;
+	case NVMRW_VAR_FLAG_DOSM:
+		nvm->flags &= ~NVM_RW_FLAG_DOSM;
+		nvm->flags |= val ? NVM_RW_FLAG_DOSM : 0;
+		break;
+	default:
+		return BDB_ERROR_NVM_INVALID_PARAMETER;
+	}
+
+	return BDB_SUCCESS;
+}
diff --git a/firmware/bdb/nvm.h b/firmware/bdb/nvm.h
index 3de1a2df..c0a55402 100644
--- a/firmware/bdb/nvm.h
+++ b/firmware/bdb/nvm.h
@@ -72,6 +72,21 @@ struct nvmrw {
 	uint8_t hmac[NVM_HMAC_SIZE];
 } __attribute__((packed));
 
+/*
+ * List of variables stored in NVM-RW. This should be exported and used by
+ * firmware and futility to access data in NVM-RW.
+ */
+enum nvmrw_var {
+	NVMRW_VAR_UPDATE_COUNT,
+	NVMRW_VAR_FLAGS,
+	NVMRW_VAR_MIN_KERNEL_DATA_KEY_VERSION,
+	NVMRW_VAR_MIN_KERNEL_VERSION,
+	NVMRW_VAR_BUC_TYPE,
+	NVMRW_VAR_FLAG_BUC_PRESENT,
+	NVMRW_VAR_FLAG_DFM_DISABLE,
+	NVMRW_VAR_FLAG_DOSM,
+};
+
 /* Size of the version 1.0 */
 #define NVM_RW_MIN_STRUCT_SIZE		96
 /* 4 Kbit EEPROM divided by 4 regions (RO,RW) x (1st,2nd) = 128 KB */
@@ -97,4 +112,28 @@ int nvmrw_read(struct vba_context *ctx);
  */
 int nvmrw_write(struct vba_context *ctx, enum nvm_type type);
 
+/**
+ * Get a value of NVM-RW variable
+ *
+ * Callers are responsible for init and verify of ctx->nvmrw.
+ *
+ * @param ctx	struct vba_context
+ * @param var	Index of the variable
+ * @param val	Destination where the value is stored
+ * @return	BDB_SUCCESS or BDB_ERROR_NVM_*
+ */
+int nvmrw_get(struct vba_context *ctx, enum nvmrw_var var, uint32_t *val);
+
+/**
+ * Set a value in NVM-RW variable
+ *
+ * Callers are responsible for init and verify of ctx->nvmrw.
+ *
+ * @param ctx	struct vba_context
+ * @param var	Index of the variable
+ * @param val	Value to be set
+ * @return	BDB_SUCCESS or BDB_ERROR_NVM_*
+ */
+int nvmrw_set(struct vba_context *ctx, enum nvmrw_var var, uint32_t val);
+
 #endif