ALSA: usbaudio: parse USB descriptors with structs

In preparation of support for v2.0 audio class, use the structs from
linux/usb/audio.h and add some new ones to describe the fields that are
actually parsed by the descriptor decoders.

Also, factor out code from usb_create_streams(). This makes it easier to
adopt the new iteration logic needed for v2.0.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 20 insertions, 17 deletions

diff --git a/sound/usb/usbmixer.c b/sound/usb/usbmixer.c
index 35b4830fb0c4..11636a6112d5 100644
--- a/sound/usb/usbmixer.c
+++ b/sound/usb/usbmixer.c
@@ -32,6 +32,8 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/usb.h>
+#include <linux/usb/audio.h>
+
 #include <sound/core.h>
 #include <sound/control.h>
 #include <sound/hwdep.h>
@@ -1086,29 +1088,30 @@ static void build_feature_ctl(struct mixer_build *state, unsigned char *desc,
  *
  * most of controlls are defined here.
  */
-static int parse_audio_feature_unit(struct mixer_build *state, int unitid, unsigned char *ftr)
+static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void *_ftr)
 {
         int channels, i, j;
         struct usb_audio_term iterm;
         unsigned int master_bits, first_ch_bits;
         int err, csize;
+        struct uac_feature_unit_descriptor *ftr = _ftr;
 
-        if (ftr[0] < 7 || ! (csize = ftr[5]) || ftr[0] < 7 + csize) {
+        if (ftr->bLength < 7 || ! (csize = ftr->bControlSize) || ftr->bLength < 7 + csize) {
                 snd_printk(KERN_ERR "usbaudio: unit %u: invalid FEATURE_UNIT descriptor\n", unitid);
                 return -EINVAL;
         }
 
         /* parse the source unit */
-        if ((err = parse_audio_unit(state, ftr[4])) < 0)
+        if ((err = parse_audio_unit(state, ftr->bSourceID)) < 0)
                 return err;
 
         /* determine the input source type and name */
-        if (check_input_term(state, ftr[4], &iterm) < 0)
+        if (check_input_term(state, ftr->bSourceID, &iterm) < 0)
                 return -EINVAL;
 
-        channels = (ftr[0] - 7) / csize - 1;
+        channels = (ftr->bLength - 7) / csize - 1;
 
-        master_bits = snd_usb_combine_bytes(ftr + 6, csize);
+        master_bits = snd_usb_combine_bytes(ftr->controls, csize);
         /* master configuration quirks */
         switch (state->chip->usb_id) {
         case USB_ID(0x08bb, 0x2702):
@@ -1119,21 +1122,21 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, unsig
                 break;
         }
         if (channels > 0)
-                first_ch_bits = snd_usb_combine_bytes(ftr + 6 + csize, csize);
+                first_ch_bits = snd_usb_combine_bytes(ftr->controls + csize, csize);
         else
                 first_ch_bits = 0;
         /* check all control types */
         for (i = 0; i < 10; i++) {
                 unsigned int ch_bits = 0;
                 for (j = 0; j < channels; j++) {
-                        unsigned int mask = snd_usb_combine_bytes(ftr + 6 + csize * (j+1), csize);
+                        unsigned int mask = snd_usb_combine_bytes(ftr->controls + csize * (j+1), csize);
                         if (mask & (1 << i))
                                 ch_bits |= (1 << j);
                 }
                 if (ch_bits & 1) /* the first channel must be set (for ease of programming) */
-                        build_feature_ctl(state, ftr, ch_bits, i, &iterm, unitid);
+                        build_feature_ctl(state, _ftr, ch_bits, i, &iterm, unitid);
                 if (master_bits & (1 << i))
-                        build_feature_ctl(state, ftr, 0, i, &iterm, unitid);
+                        build_feature_ctl(state, _ftr, 0, i, &iterm, unitid);
         }
 
         return 0;
@@ -1780,7 +1783,7 @@ static int snd_usb_mixer_dev_free(struct snd_device *device)
  */
 static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
 {
-        unsigned char *desc;
+        struct uac_output_terminal_descriptor_v1 *desc;
         struct mixer_build state;
         int err;
         const struct usbmix_ctl_map *map;
@@ -1805,13 +1808,13 @@ static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
 
         desc = NULL;
         while ((desc = snd_usb_find_csint_desc(hostif->extra, hostif->extralen, desc, OUTPUT_TERMINAL)) != NULL) {
-                if (desc[0] < 9)
+                if (desc->bLength < 9)
                         continue; /* invalid descriptor? */
-                set_bit(desc[3], state.unitbitmap);  /* mark terminal ID as visited */
-                state.oterm.id = desc[3];
-                state.oterm.type = combine_word(&desc[4]);
-                state.oterm.name = desc[8];
-                err = parse_audio_unit(&state, desc[7]);
+                set_bit(desc->bTerminalID, state.unitbitmap);  /* mark terminal ID as visited */
+                state.oterm.id = desc->bTerminalID;
+                state.oterm.type = le16_to_cpu(desc->wTerminalType);
+                state.oterm.name = desc->iTerminal;
+                err = parse_audio_unit(&state, desc->bSourceID);
                 if (err < 0)
                         return err;
         }