cbi: Separate CBI EEPROM driver from CBI protocol

Factor out the physical storage driver (cbi_eeprom.c) from the CBI
data/protocol layer (cbi.c), setting up the groundwork to support more
options of CBI sources.

BRANCH=None
BUG=b:186264627
TEST=make buildall -j

Change-Id: Ic30a6f789970dd6723cf70d4e852ddb7161f796f
Signed-off-by: Philip Chen <philipchen@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2965848
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
Commit-Queue: Philip Chen <philipchen@chromium.org>
Tested-by: Philip Chen <philipchen@chromium.org>

1 files changed, 43 insertions, 4 deletions

diff --git a/include/cros_board_info.h b/include/cros_board_info.h
index 7566bd7173..f4fa905573 100644
--- a/include/cros_board_info.h
+++ b/include/cros_board_info.h
@@ -12,7 +12,7 @@
 
 #define CBI_VERSION_MAJOR	0
 #define CBI_VERSION_MINOR	0
-#define CBI_EEPROM_SIZE		256
+#define CBI_IMAGE_SIZE		256
 static const uint8_t cbi_magic[] = { 0x43, 0x42, 0x49 };  /* 'C' 'B' 'I' */
 
 struct cbi_header {
@@ -41,6 +41,35 @@ struct cbi_data {
 	uint8_t value[];	/* data value */
 } __attribute__((packed));
 
+enum cbi_cache_status {
+	CBI_CACHE_STATUS_SYNCED = 0,
+	CBI_CACHE_STATUS_INVALID = 1
+};
+
+enum cbi_storage_type {
+	CBI_STORAGE_TYPE_EEPROM = 0,
+};
+
+/*
+ * Driver for storage media access
+ */
+struct cbi_storage_driver {
+	/* Write the whole CBI from RAM to storage media (i.e. sync) */
+	int (*store)(uint8_t *cache);
+	/*
+	 * Read blocks from storage media to RAM. Note that the granularity
+	 * of load function is asymmetrical to that of the store function.
+	 */
+	int (*load)(uint8_t offset, uint8_t *data, int len);
+	/* Return write protect status for the storage media */
+	int (*is_protected)(void);
+};
+
+struct cbi_storage_config_t {
+	enum cbi_storage_type storage_type;
+	const struct cbi_storage_driver *drv;
+};
+
 /**
  * Board info accessors
  *
@@ -161,13 +190,23 @@ int cbi_board_override(enum cbi_data_tag tag, uint8_t *buf, uint8_t *size);
  */
 int cbi_set_fw_config(uint32_t fw_config);
 
-#ifdef TEST_BUILD
 /**
- * Test only declarations. Firmware shouldn't need them.
+ * Initialize CBI cache
  */
 int cbi_create(void);
-int cbi_write(void);
+
+/**
+ * Override CBI cache status to EC_CBI_CACHE_INVALID
+ */
 void cbi_invalidate_cache(void);
+
+#ifdef TEST_BUILD
+/**
+ * Write the locally cached CBI to EEPROM.
+ *
+ * @return EC_RES_SUCCESS on success or EC_RES_* otherwise.
+ */
+int cbi_write(void);
 #endif
 
 #endif /* __CROS_EC_CROS_BOARD_INFO_H */