api: storage: Add the missing write operation support

API_dev_write(va_list ap) is currently lacking the write support
to storage devices because, historically, those devices did not
implement block_write()

The solution has been tested by loading and booting a (patched)
GRUB instance in a QEMU vexpress-a9 environment. The disk write
operations were triggered with GRUB's save_env command.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/api/api_storage.c b/api/api_storage.c
index 2b90c18aae..7ae03ac230 100644
--- a/api/api_storage.c
+++ b/api/api_storage.c
@@ -349,3 +349,27 @@ lbasize_t dev_read_stor(void *cookie, void *buf, lbasize_t len, lbastart_t start
 	return dd->block_read(dd, start, len, buf);
 #endif	/* defined(CONFIG_BLK) */
 }
+
+
+lbasize_t dev_write_stor(void *cookie, void *buf, lbasize_t len, lbastart_t start)
+{
+	struct blk_desc *dd = (struct blk_desc *)cookie;
+	int type = dev_stor_type(dd);
+
+	if (type == ENUM_MAX)
+		return 0;
+
+	if (!dev_stor_is_valid(type, dd))
+		return 0;
+
+#ifdef CONFIG_BLK
+	return blk_dwrite(dd, start, len, buf);
+#else
+	if (dd->block_write == NULL) {
+		debugf("no block_write() for device 0x%08x\n", cookie);
+		return 0;
+	}
+
+	return dd->block_write(dd, start, len, buf);
+#endif	/* defined(CONFIG_BLK) */
+}