BCH: Add readonly configuration for BCH devices

Signed-off-by: Shoukui Zhang <zhangshoukui@xiaomi.com>

drivers/bch/Kconfig

@@ -28,4 +28,10 @@ config BCH_BUFFER_ALIGNMENT
 	int "Buffer aligned bytes"
 	default 0
 
+config BCH_DEVICE_READONLY
+	bool "Set BCH device readonly"
+	default n
+	---help---
+		Set bch devices read-only
+
 endif # BCH

fs/vfs/fs_open.c

@@ -198,7 +198,11 @@ static int file_vopen(FAR struct file *filep, FAR const char *path,
 
       /* Get the file structure of the opened character driver proxy */
 
+#ifdef CONFIG_BCH_DEVICE_READONLY
+      ret = block_proxy(filep, path, O_RDOK);
+#else
       ret = block_proxy(filep, path, oflags);
+#endif
 #ifdef CONFIG_FS_NOTIFY
       if (ret >= 0)
         {