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usb: gadget: f_fs: Add flags to descriptors block
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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>
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Michal Nazarewicz authored and Felipe Balbi committed Mar 5, 2014
1 parent 8d4e897 commit ac8dde1
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Showing 3 changed files with 91 additions and 102 deletions.
132 changes: 56 additions & 76 deletions drivers/usb/gadget/f_fs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1434,7 +1434,7 @@ 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);
}
Expand All @@ -1446,12 +1446,12 @@ 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;
Expand Down Expand Up @@ -1865,89 +1865,76 @@ 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;
Expand Down Expand Up @@ -2359,8 +2346,7 @@ 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();
Expand All @@ -2376,15 +2362,9 @@ 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) {
Expand Down
12 changes: 5 additions & 7 deletions drivers/usb/gadget/u_fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -206,15 +206,13 @@ 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;
Expand Down
49 changes: 30 additions & 19 deletions include/uapi/linux/usb/functionfs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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__

Expand All @@ -29,34 +34,40 @@ struct usb_endpoint_descriptor_no_audio {
} __attribute__((packed));


/*
* 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 |
* |-----+-----------------+------+--------------------------|
Expand Down

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