[PATCH v6 0/2] usb: gadget: f_fs: Add support for SuperSpeed Mode

[PATCH v6 0/2] usb: gadget: f_fs: Add support for SuperSpeed Mode

[Manu Gautam]

Changes since v5:
* There is no change in 1st patch.
* 2nd patch from Michal updates ABI and adds new field - flags which lists
the descriptors that are present. Driver selects between the schemes based
on the magic number passed by client.
With the new scheme, usb_functionfs_descs header is removed and clients
can selectively pass descriptors and their count based on the 'flags' field.

Manu Gautam (1):
  usb: gadget: f_fs: Add support for SuperSpeed Mode

Michal Nazarewicz (1):
  usb: gadget: f_fs: Add flags to descriptors block

 drivers/usb/gadget/f_fs.c           | 214 ++++++++++++++++++++++++------------
 drivers/usb/gadget/u_fs.h           |  10 +-
 include/uapi/linux/usb/functionfs.h |  44 +++++---
 3 files changed, 177 insertions(+), 91 deletions(-)

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

[PATCH v6 1/2] usb: gadget: f_fs: Add support for SuperSpeed Mode

[Manu Gautam]

Allow userspace to pass SuperSpeed descriptors and
handle them in the driver accordingly.
This change doesn't modify existing desc_header and thereby
keeps the ABI changes backward compatible i.e. existing
userspace drivers compiled with old header (functionfs.h)
would continue to work with the updated kernel.

Signed-off-by: Manu Gautam <mgautam@codeaurora.org>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
---
 drivers/usb/gadget/f_fs.c           | 182 +++++++++++++++++++++++++++---------
 drivers/usb/gadget/u_fs.h           |  10 +-
 include/uapi/linux/usb/functionfs.h |   5 +
 3 files changed, 147 insertions(+), 50 deletions(-)

diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
index 03a68d6..5677c16 100644
--- a/drivers/usb/gadget/f_fs.c
+++ b/drivers/usb/gadget/f_fs.c
@@ -122,8 +122,8 @@ struct ffs_ep {
 	struct usb_ep			*ep;	/* P: ffs->eps_lock */
 	struct usb_request		*req;	/* P: epfile->mutex */
 
-	/* [0]: full speed, [1]: high speed */
-	struct usb_endpoint_descriptor	*descs[2];
+	/* [0]: full speed, [1]: high speed, [2]: super speed */
+	struct usb_endpoint_descriptor	*descs[3];
 
 	u8				num;
 
@@ -1185,10 +1185,11 @@ static void ffs_data_reset(struct ffs_data *ffs)
 	ffs->raw_strings = NULL;
 	ffs->stringtabs = NULL;
 
-	ffs->raw_descs_length = 0;
-	ffs->raw_fs_descs_length = 0;
+	ffs->raw_fs_hs_descs_length = 0;
+	ffs->raw_ss_descs_length = 0;
 	ffs->fs_descs_count = 0;
 	ffs->hs_descs_count = 0;
+	ffs->ss_descs_count = 0;
 
 	ffs->strings_count = 0;
 	ffs->interfaces_count = 0;
@@ -1331,7 +1332,24 @@ static int ffs_func_eps_enable(struct ffs_function *func)
 	spin_lock_irqsave(&func->ffs->eps_lock, flags);
 	do {
 		struct usb_endpoint_descriptor *ds;
-		ds = ep->descs[ep->descs[1] ? 1 : 0];
+		int desc_idx;
+
+		if (ffs->gadget->speed == USB_SPEED_SUPER)
+			desc_idx = 2;
+		else if (ffs->gadget->speed == USB_SPEED_HIGH)
+			desc_idx = 1;
+		else
+			desc_idx = 0;
+
+		/* fall-back to lower speed if desc missing for current speed */
+		do {
+			ds = ep->descs[desc_idx];
+		} while (!ds && --desc_idx >= 0);
+
+		if (!ds) {
+			ret = -EINVAL;
+			break;
+		}
 
 		ep->ep->driver_data = ep;
 		ep->ep->desc = ds;
@@ -1466,6 +1484,12 @@ static int __must_check ffs_do_desc(char *data, unsigned len,
 	}
 		break;
 
+	case USB_DT_SS_ENDPOINT_COMP:
+		pr_vdebug("EP SS companion descriptor\n");
+		if (length != sizeof(struct usb_ss_ep_comp_descriptor))
+			goto inv_length;
+		break;
+
 	case USB_DT_OTHER_SPEED_CONFIG:
 	case USB_DT_INTERFACE_POWER:
 	case USB_DT_DEBUG:
@@ -1576,8 +1600,8 @@ static int __ffs_data_do_entity(enum ffs_entity_type type,
 static int __ffs_data_got_descs(struct ffs_data *ffs,
 				char *const _data, size_t len)
 {
-	unsigned fs_count, hs_count;
-	int fs_len, ret = -EINVAL;
+	unsigned fs_count, hs_count, ss_count = 0;
+	int fs_len, hs_len, ss_len, ret = -EINVAL;
 	char *data = _data;
 
 	ENTER();
@@ -1588,9 +1612,6 @@ static int __ffs_data_got_descs(struct ffs_data *ffs,
 	fs_count = get_unaligned_le32(data +  8);
 	hs_count = get_unaligned_le32(data + 12);
 
-	if (!fs_count && !hs_count)
-		goto einval;
-
 	data += 16;
 	len  -= 16;
 
@@ -1609,22 +1630,54 @@ static int __ffs_data_got_descs(struct ffs_data *ffs,
 	}
 
 	if (likely(hs_count)) {
-		ret = ffs_do_descs(hs_count, data, len,
+		hs_len = ffs_do_descs(hs_count, data, len,
 				   __ffs_data_do_entity, ffs);
-		if (unlikely(ret < 0))
+		if (unlikely(hs_len < 0)) {
+			ret = hs_len;
+			goto error;
+		}
+
+		data += hs_len;
+		len  -= hs_len;
+	} else {
+		hs_len = 0;
+	}
+
+	if (len >= 8) {
+		/* Check SS_MAGIC for presence of ss_descs and get SS_COUNT */
+		if (get_unaligned_le32(data) != FUNCTIONFS_SS_DESC_MAGIC)
+			goto einval;
+
+		ss_count = get_unaligned_le32(data + 4);
+		data += 8;
+		len  -= 8;
+	}
+
+	if (!fs_count && !hs_count && !ss_count)
+		goto einval;
+
+	if (ss_count) {
+		ss_len = ffs_do_descs(ss_count, data, len,
+				   __ffs_data_do_entity, ffs);
+		if (unlikely(ss_len < 0)) {
+			ret = ss_len;
 			goto error;
+		}
+		ret = ss_len;
 	} else {
+		ss_len = 0;
 		ret = 0;
 	}
 
 	if (unlikely(len != ret))
 		goto einval;
 
-	ffs->raw_fs_descs_length = fs_len;
-	ffs->raw_descs_length    = fs_len + ret;
-	ffs->raw_descs           = _data;
-	ffs->fs_descs_count      = fs_count;
-	ffs->hs_descs_count      = hs_count;
+	ffs->raw_fs_hs_descs_length	 = fs_len + hs_len;
+	ffs->raw_ss_descs_length	 = ss_len;
+	ffs->raw_descs			 = _data;
+	ffs->fs_descs_count		 = fs_count;
+	ffs->hs_descs_count		 = hs_count;
+	ffs->ss_descs_count		 = ss_count;
 
 	return 0;
 
@@ -1847,21 +1900,28 @@ static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
 	struct usb_endpoint_descriptor *ds = (void *)desc;
 	struct ffs_function *func = priv;
 	struct ffs_ep *ffs_ep;
-
-	/*
-	 * If hs_descriptors is not NULL then we are reading hs
-	 * descriptors now
-	 */
-	const int isHS = func->function.hs_descriptors != NULL;
-	unsigned idx;
+	unsigned ep_desc_id, idx;
+	static const char *speed_names[] = { "full", "high", "super" };
 
 	if (type != FFS_DESCRIPTOR)
 		return 0;
 
-	if (isHS)
+	/*
+	 * If ss_descriptors is not NULL, we are reading super speed
+	 * descriptors; if hs_descriptors is not NULL, we are reading high
+	 * speed descriptors; otherwise, we are reading full speed
+	 * descriptors.
+	 */
+	if (func->function.ss_descriptors) {
+		ep_desc_id = 2;
+		func->function.ss_descriptors[(long)valuep] = desc;
+	} else if (func->function.hs_descriptors) {
+		ep_desc_id = 1;
 		func->function.hs_descriptors[(long)valuep] = desc;
-	else
+	} else {
+		ep_desc_id = 0;
 		func->function.fs_descriptors[(long)valuep]    = desc;
+	}
 
 	if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
 		return 0;
@@ -1869,13 +1929,13 @@ static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
 	idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
 	ffs_ep = func->eps + idx;
 
-	if (unlikely(ffs_ep->descs[isHS])) {
-		pr_vdebug("two %sspeed descriptors for EP %d\n",
-			  isHS ? "high" : "full",
+	if (unlikely(ffs_ep->descs[ep_desc_id])) {
+		pr_err("two %sspeed descriptors for EP %d\n",
+			  speed_names[ep_desc_id],
 			  ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 		return -EINVAL;
 	}
-	ffs_ep->descs[isHS] = ds;
+	ffs_ep->descs[ep_desc_id] = ds;
 
 	ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
 	if (ffs_ep->ep) {
@@ -2019,8 +2079,10 @@ static int _ffs_func_bind(struct usb_configuration *c,
 	const int full = !!func->ffs->fs_descs_count;
 	const int high = gadget_is_dualspeed(func->gadget) &&
 		func->ffs->hs_descs_count;
+	const int super = gadget_is_superspeed(func->gadget) &&
+		func->ffs->ss_descs_count;
 
-	int ret;
+	int fs_len, hs_len, ret;
 
 	/* Make it a single chunk, less management later on */
 	vla_group(d);
@@ -2029,15 +2091,17 @@ static int _ffs_func_bind(struct usb_configuration *c,
 		full ? ffs->fs_descs_count + 1 : 0);
 	vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
 		high ? ffs->hs_descs_count + 1 : 0);
+	vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
+		super ? ffs->ss_descs_count + 1 : 0);
 	vla_item_with_sz(d, short, inums, ffs->interfaces_count);
 	vla_item_with_sz(d, char, raw_descs,
-		high ? ffs->raw_descs_length : ffs->raw_fs_descs_length);
+			ffs->raw_fs_hs_descs_length + ffs->raw_ss_descs_length);
 	char *vlabuf;
 
 	ENTER();
 
-	/* Only high speed but not supported by gadget? */
-	if (unlikely(!(full | high)))
+	/* Has descriptors only for speeds gadget does not support */
+	if (unlikely(!(full | high | super)))
 		return -ENOTSUPP;
 
 	/* Allocate a single chunk, less management later on */
@@ -2047,8 +2111,16 @@ static int _ffs_func_bind(struct usb_configuration *c,
 
 	/* Zero */
 	memset(vla_ptr(vlabuf, d, eps), 0, d_eps__sz);
+	/* Copy only raw (hs,fs) descriptors (until ss_magic and ss_count) */
 	memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs + 16,
-	       d_raw_descs__sz);
+		ffs->raw_fs_hs_descs_length);
+	/* Copy SS descs present @ header + hs_fs_descs + ss_magic + ss_count */
+	if (func->ffs->ss_descs_count)
+		memcpy(vla_ptr(vlabuf, d, raw_descs) +
+				ffs->raw_fs_hs_descs_length,
+		       ffs->raw_descs + 16 + ffs->raw_fs_hs_descs_length + 8,
+		       ffs->raw_ss_descs_length);
+
 	memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
 	for (ret = ffs->eps_count; ret; --ret) {
 		struct ffs_ep *ptr;
@@ -2070,22 +2142,38 @@ static int _ffs_func_bind(struct usb_configuration *c,
 	 */
 	if (likely(full)) {
 		func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
-		ret = ffs_do_descs(ffs->fs_descs_count,
-				   vla_ptr(vlabuf, d, raw_descs),
-				   d_raw_descs__sz,
-				   __ffs_func_bind_do_descs, func);
-		if (unlikely(ret < 0))
+		fs_len = ffs_do_descs(ffs->fs_descs_count,
+				      vla_ptr(vlabuf, d, raw_descs),
+				      d_raw_descs__sz,
+				      __ffs_func_bind_do_descs, func);
+		if (unlikely(fs_len < 0)) {
+			ret = fs_len;
 			goto error;
+		}
 	} else {
-		ret = 0;
+		fs_len = 0;
 	}
 
 	if (likely(high)) {
 		func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
-		ret = ffs_do_descs(ffs->hs_descs_count,
-				   vla_ptr(vlabuf, d, raw_descs) + ret,
-				   d_raw_descs__sz - ret,
-				   __ffs_func_bind_do_descs, func);
+		hs_len = ffs_do_descs(ffs->hs_descs_count,
+				      vla_ptr(vlabuf, d, raw_descs) + fs_len,
+				      d_raw_descs__sz - fs_len,
+				      __ffs_func_bind_do_descs, func);
+		if (unlikely(hs_len < 0)) {
+			ret = hs_len;
+			goto error;
+		}
+	} else {
+		hs_len = 0;
+	}
+
+	if (likely(super)) {
+		func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
+		ret = ffs_do_descs(ffs->ss_descs_count,
+				vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
+				d_raw_descs__sz - fs_len - hs_len,
+				__ffs_func_bind_do_descs, func);
 		if (unlikely(ret < 0))
 			goto error;
 	}
@@ -2096,7 +2184,8 @@ static int _ffs_func_bind(struct usb_configuration *c,
 	 * now.
 	 */
 	ret = ffs_do_descs(ffs->fs_descs_count +
-			   (high ? ffs->hs_descs_count : 0),
+			   (high ? ffs->hs_descs_count : 0) +
+			   (super ? ffs->ss_descs_count : 0),
 			   vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
 			   __ffs_func_bind_do_nums, func);
 	if (unlikely(ret < 0))
@@ -2443,6 +2532,7 @@ static void ffs_func_unbind(struct usb_configuration *c,
 	 */
 	func->function.fs_descriptors = NULL;
 	func->function.hs_descriptors = NULL;
+	func->function.ss_descriptors = NULL;
 	func->interfaces_nums = NULL;
 
 	ffs_event_add(ffs, FUNCTIONFS_UNBIND);
diff --git a/drivers/usb/gadget/u_fs.h b/drivers/usb/gadget/u_fs.h
index bc2d371..08bf26e 100644
--- a/drivers/usb/gadget/u_fs.h
+++ b/drivers/usb/gadget/u_fs.h
@@ -212,14 +212,16 @@ struct ffs_data {
 	/*
 	 * Real descriptors are 16 bytes after raw_descs (so you need
 	 * to skip 16 bytes (ie. ffs->raw_descs + 16) to get to the
-	 * first full speed descriptor).  raw_descs_length and
-	 * raw_fs_descs_length do not have those 16 bytes added.
+	 * first full speed descriptor).
+	 * raw_fs_hs_descs_length does not have those 16 bytes added.
+	 * ss_descs are 8 bytes (ss_magic + count) pass the hs_descs
 	 */
 	const void			*raw_descs;
-	unsigned			raw_descs_length;
-	unsigned			raw_fs_descs_length;
+	unsigned			raw_fs_hs_descs_length;
+	unsigned			raw_ss_descs_length;
 	unsigned			fs_descs_count;
 	unsigned			hs_descs_count;
+	unsigned			ss_descs_count;
 
 	unsigned short			strings_count;
 	unsigned short			interfaces_count;
diff --git a/include/uapi/linux/usb/functionfs.h b/include/uapi/linux/usb/functionfs.h
index d6b0128..0f8f7be 100644
--- a/include/uapi/linux/usb/functionfs.h
+++ b/include/uapi/linux/usb/functionfs.h
@@ -13,6 +13,7 @@ enum {
 	FUNCTIONFS_STRINGS_MAGIC     = 2
 };
 
+#define FUNCTIONFS_SS_DESC_MAGIC 0x0055DE5C
 
 #ifndef __KERNEL__
 
@@ -50,7 +51,11 @@ struct usb_functionfs_descs_head {
  * |  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:
  *
  * | off | name            | type | description              |
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

[PATCH v6 2/2] usb: gadget: f_fs: Add flags to descriptors block

[Manu Gautam]

From: Michal Nazarewicz <mina86@mina86.com>

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>
---
 drivers/usb/gadget/f_fs.c           | 132 +++++++++++++++---------------------
 drivers/usb/gadget/u_fs.h           |  12 ++--
 include/uapi/linux/usb/functionfs.h |  49 +++++++------
 3 files changed, 91 insertions(+), 102 deletions(-)

diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
index 5677c16..485a3fa 100644
--- a/drivers/usb/gadget/f_fs.c
+++ b/drivers/usb/gadget/f_fs.c
@@ -1169,7 +1169,7 @@ static void ffs_data_clear(struct ffs_data *ffs)
 	if (ffs->epfiles)
 		ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
 
-	kfree(ffs->raw_descs);
+	kfree(ffs->raw_descs_data);
 	kfree(ffs->raw_strings);
 	kfree(ffs->stringtabs);
 }
@@ -1181,12 +1181,12 @@ static void ffs_data_reset(struct ffs_data *ffs)
 	ffs_data_clear(ffs);
 
 	ffs->epfiles = NULL;
+	ffs->raw_descs_data = NULL;
 	ffs->raw_descs = NULL;
 	ffs->raw_strings = NULL;
 	ffs->stringtabs = NULL;
 
-	ffs->raw_fs_hs_descs_length = 0;
-	ffs->raw_ss_descs_length = 0;
+	ffs->raw_descs_length = 0;
 	ffs->fs_descs_count = 0;
 	ffs->hs_descs_count = 0;
 	ffs->ss_descs_count = 0;
@@ -1600,89 +1600,76 @@ static int __ffs_data_do_entity(enum ffs_entity_type type,
 static int __ffs_data_got_descs(struct ffs_data *ffs,
 				char *const _data, size_t len)
 {
-	unsigned fs_count, hs_count, ss_count = 0;
-	int fs_len, hs_len, ss_len, ret = -EINVAL;
-	char *data = _data;
+	char *data = _data, *raw_descs;
+	unsigned counts[3], flags;
+	int ret = -EINVAL, i;
 
 	ENTER();
 
-	if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_DESCRIPTORS_MAGIC ||
-		     get_unaligned_le32(data + 4) != len))
+	if (get_unaligned_le32(data + 4) != len)
 		goto error;
-	fs_count = get_unaligned_le32(data +  8);
-	hs_count = get_unaligned_le32(data + 12);
-
-	data += 16;
-	len  -= 16;
 
-	if (likely(fs_count)) {
-		fs_len = ffs_do_descs(fs_count, data, len,
-				      __ffs_data_do_entity, ffs);
-		if (unlikely(fs_len < 0)) {
-			ret = fs_len;
+	switch (get_unaligned_le32(data)) {
+	case FUNCTIONFS_DESCRIPTORS_MAGIC:
+		flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
+		data += 8;
+		len  -= 8;
+		break;
+	case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
+		flags = get_unaligned_le32(data + 8);
+		if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
+			      FUNCTIONFS_HAS_HS_DESC |
+			      FUNCTIONFS_HAS_SS_DESC)) {
+			ret = -ENOSYS;
 			goto error;
 		}
-
-		data += fs_len;
-		len  -= fs_len;
-	} else {
-		fs_len = 0;
+		data += 12;
+		len  -= 12;
+		break;
+	default:
+		goto error;
 	}
 
-	if (likely(hs_count)) {
-		hs_len = ffs_do_descs(hs_count, data, len,
-				   __ffs_data_do_entity, ffs);
-		if (unlikely(hs_len < 0)) {
-			ret = hs_len;
+	/* Read fs_count, hs_count and ss_count (if present) */
+	for (i = 0; i < 3; ++i) {
+		if (!(flags & (1 << i))) {
+			counts[i] = 0;
+		} else if (len < 4) {
 			goto error;
+		} else {
+			counts[i] = get_unaligned_le32(data);
+			data += 4;
+			len  -= 4;
 		}
-
-		data += hs_len;
-		len  -= hs_len;
-	} else {
-		hs_len = 0;
-	}
-
-	if (len >= 8) {
-		/* Check SS_MAGIC for presence of ss_descs and get SS_COUNT */
-		if (get_unaligned_le32(data) != FUNCTIONFS_SS_DESC_MAGIC)
-			goto einval;
-
-		ss_count = get_unaligned_le32(data + 4);
-		data += 8;
-		len  -= 8;
 	}
 
-	if (!fs_count && !hs_count && !ss_count)
-		goto einval;
-
-	if (ss_count) {
-		ss_len = ffs_do_descs(ss_count, data, len,
+	/* Read descriptors */
+	raw_descs = data;
+	for (i = 0; i < 3; ++i) {
+		if (!counts[i])
+			continue;
+		ret = ffs_do_descs(counts[i], data, len,
 				   __ffs_data_do_entity, ffs);
-		if (unlikely(ss_len < 0)) {
-			ret = ss_len;
+		if (ret < 0)
 			goto error;
-		}
-		ret = ss_len;
-	} else {
-		ss_len = 0;
-		ret = 0;
+		data += ret;
+		len  -= ret;
 	}
 
-	if (unlikely(len != ret))
-		goto einval;
+	if (raw_descs == data || len) {
+		ret = -EINVAL;
+		goto error;
+	}
 
-	ffs->raw_fs_hs_descs_length	 = fs_len + hs_len;
-	ffs->raw_ss_descs_length	 = ss_len;
-	ffs->raw_descs			 = _data;
-	ffs->fs_descs_count		 = fs_count;
-	ffs->hs_descs_count		 = hs_count;
-	ffs->ss_descs_count		 = ss_count;
+	ffs->raw_descs_data	= _data;
+	ffs->raw_descs		= raw_descs;
+	ffs->raw_descs_length	= data - raw_descs;
+	ffs->fs_descs_count	= counts[0];
+	ffs->hs_descs_count	= counts[1];
+	ffs->ss_descs_count	= counts[2];
 
 	return 0;
 
-einval:
-	ret = -EINVAL;
 error:
 	kfree(_data);
 	return ret;
@@ -2094,8 +2081,7 @@ static int _ffs_func_bind(struct usb_configuration *c,
 	vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
 		super ? ffs->ss_descs_count + 1 : 0);
 	vla_item_with_sz(d, short, inums, ffs->interfaces_count);
-	vla_item_with_sz(d, char, raw_descs,
-			ffs->raw_fs_hs_descs_length + ffs->raw_ss_descs_length);
+	vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
 	char *vlabuf;
 
 	ENTER();
@@ -2111,15 +2097,9 @@ static int _ffs_func_bind(struct usb_configuration *c,
 
 	/* Zero */
 	memset(vla_ptr(vlabuf, d, eps), 0, d_eps__sz);
-	/* Copy only raw (hs,fs) descriptors (until ss_magic and ss_count) */
-	memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs + 16,
-		ffs->raw_fs_hs_descs_length);
-	/* Copy SS descs present @ header + hs_fs_descs + ss_magic + ss_count */
-	if (func->ffs->ss_descs_count)
-		memcpy(vla_ptr(vlabuf, d, raw_descs) +
-				ffs->raw_fs_hs_descs_length,
-		       ffs->raw_descs + 16 + ffs->raw_fs_hs_descs_length + 8,
-		       ffs->raw_ss_descs_length);
+	/* Copy descriptors  */
+	memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
+	       ffs->raw_descs_length);
 
 	memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
 	for (ret = ffs->eps_count; ret; --ret) {
diff --git a/drivers/usb/gadget/u_fs.h b/drivers/usb/gadget/u_fs.h
index 08bf26e..46ddda9 100644
--- a/drivers/usb/gadget/u_fs.h
+++ b/drivers/usb/gadget/u_fs.h
@@ -210,15 +210,13 @@ struct ffs_data {
 
 	/* filled by __ffs_data_got_descs() */
 	/*
-	 * Real descriptors are 16 bytes after raw_descs (so you need
-	 * to skip 16 bytes (ie. ffs->raw_descs + 16) to get to the
-	 * first full speed descriptor).
-	 * raw_fs_hs_descs_length does not have those 16 bytes added.
-	 * ss_descs are 8 bytes (ss_magic + count) pass the hs_descs
+	 * raw_descs is what you kfree, real_descs points inside of raw_descs,
+	 * where full speed, high speed and super speed descriptors start.
+	 * real_descs_length is the length of all those descriptors.
 	 */
+	const void			*raw_descs_data;
 	const void			*raw_descs;
-	unsigned			raw_fs_hs_descs_length;
-	unsigned			raw_ss_descs_length;
+	unsigned			raw_descs_length;
 	unsigned			fs_descs_count;
 	unsigned			hs_descs_count;
 	unsigned			ss_descs_count;
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 @@ struct usb_endpoint_descriptor_no_audio {
 
 
 /*
- * 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              |
  * |-----+-----------------+------+--------------------------|
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Re: [PATCH v6 0/2] usb: gadget: f_fs: Add support for SuperSpeed Mode

[Michal Nazarewicz]

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On Fri, Feb 28 2014, Manu Gautam <mgautam@codeaurora.org> wrote:
> Changes since v5:
> * There is no change in 1st patch.
> * 2nd patch from Michal updates ABI and adds new field - flags which lists
> the descriptors that are present. Driver selects between the schemes based
> on the magic number passed by client.
> With the new scheme, usb_functionfs_descs header is removed and clients
> can selectively pass descriptors and their count based on the 'flags' field.

Thanks for testing and fixes!  Looks good to me.

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +--<mpn@google.com>--<xmpp:mina86@jabber.org>--ooO--(_)--Ooo--

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