usb: gadget: f_fs: Add flags to descriptors block
This reworks the way SuperSpeed descriptors are added and instead of
having a magic after full and high speed descriptors, it reworks the
whole descriptors block to include a flags field which lists which
descriptors are present and makes future extensions possible.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/include/uapi/linux/usb/functionfs.h b/include/uapi/linux/usb/functionfs.h
index 0f8f7be..2a4b4a7 100644
--- a/include/uapi/linux/usb/functionfs.h
+++ b/include/uapi/linux/usb/functionfs.h
@@ -10,10 +10,15 @@
enum {
FUNCTIONFS_DESCRIPTORS_MAGIC = 1,
- FUNCTIONFS_STRINGS_MAGIC = 2
+ FUNCTIONFS_STRINGS_MAGIC = 2,
+ FUNCTIONFS_DESCRIPTORS_MAGIC_V2 = 3,
};
-#define FUNCTIONFS_SS_DESC_MAGIC 0x0055DE5C
+enum functionfs_flags {
+ FUNCTIONFS_HAS_FS_DESC = 1,
+ FUNCTIONFS_HAS_HS_DESC = 2,
+ FUNCTIONFS_HAS_SS_DESC = 4,
+};
#ifndef __KERNEL__
@@ -30,33 +35,39 @@
/*
- * All numbers must be in little endian order.
- */
-
-struct usb_functionfs_descs_head {
- __le32 magic;
- __le32 length;
- __le32 fs_count;
- __le32 hs_count;
-} __attribute__((packed));
-
-/*
* Descriptors format:
*
* | off | name | type | description |
* |-----+-----------+--------------+--------------------------------------|
- * | 0 | magic | LE32 | FUNCTIONFS_{FS,HS}_DESCRIPTORS_MAGIC |
+ * | 0 | magic | LE32 | FUNCTIONFS_DESCRIPTORS_MAGIC_V2 |
+ * | 4 | length | LE32 | length of the whole data chunk |
+ * | 8 | flags | LE32 | combination of functionfs_flags |
+ * | | fs_count | LE32 | number of full-speed descriptors |
+ * | | hs_count | LE32 | number of high-speed descriptors |
+ * | | ss_count | LE32 | number of super-speed descriptors |
+ * | | fs_descrs | Descriptor[] | list of full-speed descriptors |
+ * | | hs_descrs | Descriptor[] | list of high-speed descriptors |
+ * | | ss_descrs | Descriptor[] | list of super-speed descriptors |
+ *
+ * Depending on which flags are set, various fields may be missing in the
+ * structure. Any flags that are not recognised cause the whole block to be
+ * rejected with -ENOSYS.
+ *
+ * Legacy descriptors format:
+ *
+ * | off | name | type | description |
+ * |-----+-----------+--------------+--------------------------------------|
+ * | 0 | magic | LE32 | FUNCTIONFS_DESCRIPTORS_MAGIC |
* | 4 | length | LE32 | length of the whole data chunk |
* | 8 | fs_count | LE32 | number of full-speed descriptors |
* | 12 | hs_count | LE32 | number of high-speed descriptors |
* | 16 | fs_descrs | Descriptor[] | list of full-speed descriptors |
* | | hs_descrs | Descriptor[] | list of high-speed descriptors |
- * | | ss_magic | LE32 | FUNCTIONFS_SS_DESC_MAGIC |
- * | | ss_count | LE32 | number of super-speed descriptors |
- * | | ss_descrs | Descriptor[] | list of super-speed descriptors |
*
- * ss_magic: if present then it implies that SS_DESCs are also present
- * descs are just valid USB descriptors and have the following format:
+ * All numbers must be in little endian order.
+ *
+ * Descriptor[] is an array of valid USB descriptors which have the following
+ * format:
*
* | off | name | type | description |
* |-----+-----------------+------+--------------------------|