Add USB Audio 1.0 support

Original commit credit to Amaury Pouly, Moshe Piekarski
Pushed across the finish line by Dana Conrad

To enable, see setting under General Settings --> System --> USB-DAC.
On devices with few endpoints, this may not work while HID and/or
mass storage is enabled.

Adds new dedicated mixer channel.

setting usb-dac can have values:
- never (0)
- always (1)
- while_charge_only (2)
- while_mass_storage (3)

Relevant devices are DWC2 and ARC usb controller devices. That being:
x1000 Native targets (m3k, erosqnative, q1, others...?),
sansac200, creativezenxfi2, vibe500, ipodmini2g,
ipod4g, creativezenxfi, creativezenxfi3, sansaview, ipodcolor,
creativezenxfistyle, samsungypz5, sansafuzeplus, iriverh10_5gb,
tatungtpj1022, gigabeats, faketarget, samsungyh820, gogearhdd1630, samsungyh925, ipodmini1g, ipodvideo, creativezenmozaic, sonynwze370, creativezen, gogearsa9200, gogearhdd6330, sonynwze360, sansae200, mrobe100, iriverh10, creativezenv, ipodnano1g, samsungyh920

USB Driver-wise, it should be noted that this patch requires some
slight changes:
- proper blocking on control OUT transfers, to make sure the data is
  received *before* using it, the usb_core should probably use that too
- drivers can now support interface alternate settings
- drivers can be notified of completion by a new fast handler, which
  is called directly from the driver; this is is necessary for
  isochronous transfers because going through the usb queue is way too
  slow

Designware changes:

- enable for USBOTG_DESIGNWARE
- set maxpacketsize to 1023 for ISO endpoints

Change-Id: I570871884a4e4820b4312b203b07701f06ecacc6

apps/debug_menu.c

@@ -116,6 +116,9 @@
 
 #ifdef HAVE_USBSTACK
 #include "usb_core.h"
+#ifdef USB_ENABLE_AUDIO
+#include "../usbstack/usb_audio.h"
+#endif
 #endif
 
 #include "talk.h"
@@ -2509,18 +2512,56 @@ static bool dbg_talk(void)
 }
 
 #ifdef HAVE_USBSTACK
-#if defined(ROCKBOX_HAS_LOGF) && defined(USB_ENABLE_SERIAL)
+#if (defined(ROCKBOX_HAS_LOGF) && defined(USB_ENABLE_SERIAL))
-static bool toggle_usb_serial(void)
+static bool toggle_usb_core_driver(int driver, char *msg)
 {
-    bool enabled = !usb_core_driver_enabled(USB_DRIVER_SERIAL);
+    bool enabled = !usb_core_driver_enabled(driver);
 
-    usb_core_enable_driver(USB_DRIVER_SERIAL, enabled);
+    usb_core_enable_driver(driver,enabled);
-    splashf(HZ, "USB Serial %sabled", enabled ? "en" : "dis");
+    splashf(HZ, "%s %s", msg, enabled ? "enabled" : "disabled");
 
     return false;
 }
+
+#ifdef USB_ENABLE_SERIAL
+static bool toggle_usb_serial(void)
+{
+    return toggle_usb_core_driver(USB_DRIVER_SERIAL, "USB Serial");
+}
+#endif /* USB_ENABLE_SERIAL */
 #endif
-#endif
+
+#ifdef USB_ENABLE_AUDIO
+static int dbg_usb_audio_cb(int action, struct gui_synclist *lists)
+{
+    (void)lists;
+    simplelist_reset_lines();
+    simplelist_addline("%sabled", usb_core_driver_enabled(USB_DRIVER_AUDIO)?"En":"Dis");
+    simplelist_addline("%sPlaying", usb_audio_get_playing()?"":"Not ");
+    simplelist_addline("iface: %d alt: %d", usb_audio_get_main_intf(), usb_audio_get_alt_intf());
+    simplelist_addline("out ep: 0x%X in ep: 0x%X", usb_audio_get_out_ep(), usb_audio_get_in_ep());
+    simplelist_addline("Volume: %d", usb_audio_get_cur_volume());
+    simplelist_addline("Playback Frequency: %lu", usb_audio_get_playback_sampling_frequency());
+    simplelist_addline("Buffers filled: %d", usb_audio_get_prebuffering());
+    simplelist_addline("%s", usb_audio_get_underflow()?"UNDERFLOW!":" ");
+    simplelist_addline("%s", usb_audio_get_overflow()?"OVERFLOW!":" ");
+    simplelist_addline("%s", usb_audio_get_alloc_failed()?"ALLOC FAILED!":" ");
+    if (action == ACTION_NONE)
+    {
+        action = ACTION_REDRAW;
+    }
+    return action;
+}
+static bool dbg_usb_audio(void)
+{
+    struct simplelist_info info;
+    simplelist_info_init(&info, "USB Audio", 0, NULL);
+    info.scroll_all = true;
+    info.action_callback = dbg_usb_audio_cb;
+    return simplelist_show_list(&info);
+}
+#endif /* USB_ENABLE_AUDIO */
+#endif /* HAVE_USBSTACK */
 
 #if CONFIG_USBOTG == USBOTG_ISP1583
 extern int dbg_usb_num_items(void);
@@ -2847,6 +2888,9 @@ static const struct {
 #if defined(ROCKBOX_HAS_LOGF) && defined(USB_ENABLE_SERIAL)
         {"USB Serial driver (logf)", toggle_usb_serial },
 #endif
+#if defined(USB_ENABLE_AUDIO)
+        {"USB-DAC", dbg_usb_audio},
+#endif
 #endif /* HAVE_USBSTACK */
 #ifdef CPU_BOOST_LOGGING
         {"Show cpu_boost log",cpu_boost_log},

apps/lang/english.lang

@@ -10370,6 +10370,62 @@
     usb_hid: "Mouse"
   </voice>
 </phrase>
+<phrase>
+  id: LANG_USB_DAC
+  desc: in settings_menu
+  user: core
+  <source>
+    *: "USB-DAC"
+  </source>
+  <dest>
+    *: "USB-DAC"
+  </dest>
+  <voice>
+    *: "USB-DAC"
+  </voice>
+</phrase>
+<phrase>
+  id: LANG_WHILE_USB_CHARGE_ONLY
+  desc: in settings_menu
+  user: core
+  <source>
+    *: "While In USB Charge-Only Mode"
+  </source>
+  <dest>
+    *: "While In USB Charge-Only Mode"
+  </dest>
+  <voice>
+    *: "While In USB Charge-Only Mode"
+  </voice>
+</phrase>
+<phrase>
+  id: LANG_WHILE_MASS_STORAGE_USB_ONLY
+  desc: in settings_menu
+  user: core
+  <source>
+    *: "While In USB Mass-Storage Mode"
+  </source>
+  <dest>
+    *: "While In USB Mass-Storage Mode"
+  </dest>
+  <voice>
+    *: "While In USB Mass-Storage Mode"
+  </voice>
+</phrase>
+<phrase>
+  id: LANG_USB_DAC_ACTIVE
+  desc: for splash
+  user: core
+  <source>
+    *: "USB-DAC Active"
+  </source>
+  <dest>
+    *: "USB-DAC Active"
+  </dest>
+  <voice>
+    *: "USB-DAC Active"
+  </voice>
+</phrase>
 <phrase>
   id: LANG_SCROLLBAR_WIDTH
   desc: in Settings -> General -> Display -> Status-/Scrollbar

apps/menus/settings_menu.c

@@ -358,6 +358,9 @@ MENUITEM_SETTING(lineout_onoff, &global_settings.lineout_active, NULL);
 MENUITEM_SETTING(usb_hid, &global_settings.usb_hid, NULL);
 MENUITEM_SETTING(usb_keypad_mode, &global_settings.usb_keypad_mode, NULL);
 #endif
+#ifdef USB_ENABLE_AUDIO
+MENUITEM_SETTING(usb_audio, &global_settings.usb_audio, NULL);
+#endif
 #if defined(USB_ENABLE_STORAGE) && defined(HAVE_MULTIDRIVE)
 MENUITEM_SETTING(usb_skip_first_drive, &global_settings.usb_skip_first_drive, NULL);
 #endif
@@ -454,6 +457,9 @@ MAKE_MENU(system_menu, ID2P(LANG_SYSTEM),
             &usb_hid,
             &usb_keypad_mode,
 #endif
+#ifdef USB_ENABLE_AUDIO
+            &usb_audio,
+#endif
 #if defined(USB_ENABLE_STORAGE) && defined(HAVE_MULTIDRIVE)
             &usb_skip_first_drive,
 #endif

apps/settings.h

@@ -823,6 +823,10 @@ struct user_settings
     int usb_keypad_mode;
 #endif
 
+#ifdef USB_ENABLE_AUDIO
+    int usb_audio;
+#endif
+
 #if defined(USB_ENABLE_STORAGE) && defined(HAVE_MULTIDRIVE)
     bool usb_skip_first_drive;
 #endif

apps/settings_list.c

@@ -2315,6 +2315,11 @@ const struct settings_list settings[] = {
     ), /* CHOICE_SETTING( usb_keypad_mode ) */
 #endif
 
+#ifdef USB_ENABLE_AUDIO
+    CHOICE_SETTING(0, usb_audio, LANG_USB_DAC, 0, "usb-dac", "never,always,while_charge_only,while_mass_storage", usb_set_audio, 4,
+        ID2P(LANG_NEVER), ID2P(LANG_ALWAYS), ID2P(LANG_WHILE_USB_CHARGE_ONLY), ID2P(LANG_WHILE_MASS_STORAGE_USB_ONLY)),
+#endif
+
 #if defined(USB_ENABLE_STORAGE) && defined(HAVE_MULTIDRIVE)
     OFFON_SETTING(0, usb_skip_first_drive, LANG_USB_SKIP_FIRST_DRIVE, false, "usb skip first drive", usb_set_skip_first_drive),
 #endif

firmware/SOURCES

@@ -935,6 +935,9 @@ usbstack/usb_storage.c
 #ifdef USB_ENABLE_SERIAL
 usbstack/usb_serial.c
 #endif
+#ifdef USB_ENABLE_AUDIO
+usbstack/usb_audio.c
+#endif
 #ifdef USB_ENABLE_CHARGING_ONLY
 usbstack/usb_charging_only.c
 #endif

firmware/drivers/usb-designware.c

@@ -231,7 +231,7 @@ static void usb_dw_set_stall(int epnum, enum usb_dw_epdir epdir, int stall)
     else
     {
         DWC_EPCTL(epnum, epdir) &= ~STALL;
-        DWC_EPCTL(epnum, epdir) |= SD0PID;
+        DWC_EPCTL(epnum, epdir) |= SETD0PIDEF;
     }
 }
 
@@ -668,7 +668,7 @@ static void usb_dw_unconfigure_ep(int epnum, enum usb_dw_epdir epdir)
 static int usb_dw_configure_ep(int epnum,
                 enum usb_dw_epdir epdir, int type, int maxpktsize)
 {
-    uint32_t epctl = SD0PID|EPTYP(type)|USBAEP|maxpktsize;
+    uint32_t epctl = SETD0PIDEF|EPTYP(type)|USBAEP|maxpktsize;
 
     if (epdir == USB_DW_EPDIR_IN)
     {
@@ -1259,7 +1259,7 @@ static void usb_dw_irq(void)
                          * FIFO and raises StatusRecvd | XferCompl.
                          *
                          * We do not need or want this -- we've already handled
-                         * the data phase by this point -- but EP0 is stoppped
+                         * the data phase by this point -- but EP0 is stopped
                          * as a side effect of XferCompl, so we need to restart
                          * it to keep receiving packets. */
                         usb_dw_ep0_recv();
@@ -1528,7 +1528,7 @@ void usb_drv_cancel_all_transfers()
                 {
                     //usb_dw_flush_endpoint(ep, dir);
                     usb_dw_abort_endpoint(ep, dir);
-                    DWC_EPCTL(ep, dir) |= SD0PID;
+                    DWC_EPCTL(ep, dir) |= SETD0PIDEF;
                 }
     usb_dw_target_enable_irq();
 }
@@ -1606,8 +1606,15 @@ int usb_drv_request_endpoint(int type, int dir)
             struct usb_dw_ep* dw_ep = usb_dw_get_ep(ep, epdir);
             if (!dw_ep->active)
             {
+                int maxpktsize = 64;
+                if (type == EPTYP_ISOCHRONOUS){
+                    maxpktsize = 1023;
+                } else {
+                    maxpktsize = usb_drv_port_speed() ? 512 : 64;
+                }
+
                 if (usb_dw_configure_ep(ep, epdir, type,
-                                usb_drv_port_speed() ? 512 : 64) >= 0)
+                                maxpktsize) >= 0)
                 {
                     dw_ep->active = true;
                     request_ep = ep | dir;
@@ -1679,3 +1686,11 @@ void usb_drv_control_response(enum usb_control_response resp,
     usb_dw_control_response(resp, data, length);
     usb_dw_target_enable_irq();
 }
+
+int usb_drv_get_frame_number()
+{
+    // SOFFN is 14 bits, the least significant 3 appear to be some sort of microframe count.
+    // The USB spec says a frame number is 11 bits. This way we get 1 frame per millisecond,
+    // just like we're supposed to!
+    return (DWC_DSTS >> 11) & 0x7FF;
+}

firmware/export/config.h

@@ -1347,6 +1347,7 @@ Lyre prototype 1 */
 #elif (CONFIG_USBOTG == USBOTG_DESIGNWARE)
 #define USB_HAS_BULK
 #define USB_HAS_INTERRUPT
+#define USB_HAS_ISOCHRONOUS
 #elif (CONFIG_USBOTG == USBOTG_ARC) ||  \
     (CONFIG_USBOTG == USBOTG_JZ4740) || \
     (CONFIG_USBOTG == USBOTG_JZ4760) || \
@@ -1356,6 +1357,9 @@ Lyre prototype 1 */
     (CONFIG_USBOTG == USBOTG_TNETV105)
 #define USB_HAS_BULK
 #define USB_HAS_INTERRUPT
+#if (CONFIG_USBOTG == USBOTG_ARC)
+#define USB_HAS_ISOCHRONOUS
+#endif
 #define USB_LEGACY_CONTROL_API
 #elif defined(CPU_TCC780X)
 #define USB_HAS_BULK
@@ -1366,11 +1370,6 @@ Lyre prototype 1 */
 //#define USB_HAS_INTERRUPT -- seems to be broken
 #endif /* CONFIG_USBOTG */
 
-#if (CONFIG_USBOTG == USBOTG_ARC) || \
-    (CONFIG_USBOTG == USBOTG_AS3525)
-#define USB_HAS_ISOCHRONOUS
-#endif
-
 /* define the class drivers to enable */
 #ifdef BOOTLOADER
 
@@ -1398,6 +1397,10 @@ Lyre prototype 1 */
 #endif
 #endif
 
+#ifdef USB_HAS_ISOCHRONOUS
+#define USB_ENABLE_AUDIO
+#endif
+
 #endif /* BOOTLOADER */
 
 #endif /* HAVE_USBSTACK */

firmware/export/pcm_mixer.h

@@ -72,6 +72,9 @@
 enum pcm_mixer_channel
 {
     PCM_MIXER_CHAN_PLAYBACK = 0,
+#ifdef USB_ENABLE_AUDIO
+    PCM_MIXER_CHAN_USBAUDIO,
+#endif
     PCM_MIXER_CHAN_VOICE,
 #ifndef HAVE_HARDWARE_BEEP
     PCM_MIXER_CHAN_BEEP,

firmware/export/usb-designware.h

@@ -200,7 +200,8 @@
 #define DWC_DOEPCTL(x)      (*((REG32_PTR_T)(OTGBASE + 0xb00 + 0x20*(x))))
     #define EPENA           (1<<31)
     #define EPDIS           (1<<30)
-    #define SD0PID          (1<<28)
+    #define SETD1PIDOF      (1<<29)
+    #define SETD0PIDEF      (1<<28)
     #define SNAK            (1<<27)
     #define CNAK            (1<<26)
     #define DTXFNUM(x)      ((x)<<22)

firmware/export/usb.h

@@ -167,6 +167,9 @@ enum {
 #endif
 #ifdef USB_ENABLE_HID
     USB_DRIVER_HID,
+#endif
+#ifdef USB_ENABLE_AUDIO
+    USB_DRIVER_AUDIO,
 #endif
     USB_NUM_DRIVERS
 };
@@ -256,6 +259,10 @@ void usb_firewire_connect_event(void);
 void usb_set_hid(bool enable);
 #endif
 
+#ifdef USB_ENABLE_AUDIO
+void usb_set_audio(int value);
+#endif
+
 #if defined(USB_ENABLE_STORAGE) && defined(HAVE_MULTIDRIVE)
 /* when the target has several drives, decide whether mass storage should
  * skip the first drive. This is useful when the second drive is a SD card

firmware/export/usb_ch9.h

@@ -339,6 +339,12 @@ struct usb_endpoint_descriptor {
 #define USB_ENDPOINT_NUMBER_MASK        0x0f    /* in bEndpointAddress */
 #define USB_ENDPOINT_DIR_MASK           0x80
 
+#define USB_ENDPOINT_SYNCTYPE_MASK      0x0c    /* in bmAttributes */
+#define USB_ENDPOINT_SYNC_NONE          (0 << 2)
+#define USB_ENDPOINT_SYNC_ASYNC         (1 << 2)
+#define USB_ENDPOINT_SYNC_ADAPTIVE      (2 << 2)
+#define USB_ENDPOINT_SYNC_SYNC          (3 << 2)
+
 #define USB_ENDPOINT_XFERTYPE_MASK      0x03    /* in bmAttributes */
 #define USB_ENDPOINT_XFER_CONTROL       0
 #define USB_ENDPOINT_XFER_ISOC          1

firmware/export/usb_drv.h

@@ -74,6 +74,7 @@ void usb_drv_stall(int endpoint, bool stall,bool in);
 bool usb_drv_stalled(int endpoint,bool in);
 int usb_drv_send(int endpoint, void* ptr, int length);
 int usb_drv_send_nonblocking(int endpoint, void* ptr, int length);
+int usb_drv_recv_blocking(int endpoint, void* ptr, int length);
 int usb_drv_recv_nonblocking(int endpoint, void* ptr, int length);
 void usb_drv_control_response(enum usb_control_response resp,
                               void* data, int length);
@@ -86,6 +87,14 @@ void usb_drv_set_test_mode(int mode);
 bool usb_drv_connected(void);
 int usb_drv_request_endpoint(int type, int dir);
 void usb_drv_release_endpoint(int ep);
+#ifdef USB_HAS_ISOCHRONOUS
+/* returns the last received frame number (the 11-bit number contained in the last SOF):
+ * - full-speed: the host sends one SOF every 1ms (so 1000 SOF/s)
+ * - high-speed: the hosts sends one SOF every 125us but each consecutive 8 SOF have the same frame
+ *   number
+ * thus in all mode, the frame number can be interpreted as the current millisecond *in USB time*. */
+int usb_drv_get_frame_number(void);
+#endif
 
 /* USB_STRING_INITIALIZER(u"Example String") */
 #define USB_STRING_INITIALIZER(S) { \

firmware/target/arm/usb-drv-arc.c

@@ -599,11 +599,22 @@ int usb_drv_recv_nonblocking(int endpoint, void* ptr, int length)
     return prime_transfer(EP_NUM(endpoint), ptr, length, false, false);
 }
 
+int usb_drv_recv_blocking(int endpoint, void* ptr, int length)
+{
+    return prime_transfer(EP_NUM(endpoint), ptr, length, false, true);
+}
+
 int usb_drv_port_speed(void)
 {
     return (REG_PORTSC1 & 0x08000000) ? 1 : 0;
 }
 
+int usb_drv_get_frame_number(void)
+{
+    /* the lower 3 bits store the microframe (in HS mode), discard them */
+    return (REG_FRINDEX & USB_FRINDEX_MASKS) >> 3;
+}
+
 bool usb_drv_connected(void)
 {
     return (REG_PORTSC1 &
@@ -970,10 +981,8 @@ static void init_control_queue_heads(void)
 /* manual: 32.14.4.1 Queue Head Initialization */
 static void init_queue_heads(void)
 {
-    /* FIXME the packetsize for isochronous transfers is 1023 : 1024 but
-     * the current code only support one type of packet size so we restrict
-     * isochronous packet size for now also */
     int packetsize = (usb_drv_port_speed() ? 512 : 64);
+    int isopacketsize = (usb_drv_port_speed() ? 1024 : 1024);
     int i;
 
     /* TODO: this should take ep_allocation into account */
@@ -982,7 +991,7 @@ static void init_queue_heads(void)
         /* OUT */
         if(endpoints[i].type[DIR_OUT] == USB_ENDPOINT_XFER_ISOC)
             /* FIXME: we can adjust the number of packets per frame, currently use one */
-            qh_array[i*2].max_pkt_length = packetsize << QH_MAX_PKT_LEN_POS | QH_ZLT_SEL | 1 << QH_MULT_POS;
+            qh_array[i*2].max_pkt_length = isopacketsize << QH_MAX_PKT_LEN_POS | QH_ZLT_SEL | 1 << QH_MULT_POS;
         else
             qh_array[i*2].max_pkt_length = packetsize << QH_MAX_PKT_LEN_POS | QH_ZLT_SEL;
 
@@ -991,7 +1000,7 @@ static void init_queue_heads(void)
         /* IN */
         if(endpoints[i].type[DIR_IN] == USB_ENDPOINT_XFER_ISOC)
             /* FIXME: we can adjust the number of packets per frame, currently use one */
-            qh_array[i*2+1].max_pkt_length = packetsize << QH_MAX_PKT_LEN_POS | QH_ZLT_SEL | 1 << QH_MULT_POS;
+            qh_array[i*2+1].max_pkt_length = isopacketsize << QH_MAX_PKT_LEN_POS | QH_ZLT_SEL | 1 << QH_MULT_POS;
         else
             qh_array[i*2+1].max_pkt_length = packetsize << QH_MAX_PKT_LEN_POS | QH_ZLT_SEL;
 

firmware/usb.c

@@ -97,6 +97,9 @@ static bool exclusive_storage_access = false;
 #ifdef USB_ENABLE_HID
 static bool usb_hid = true;
 #endif
+#ifdef USB_ENABLE_AUDIO
+static int usb_audio = 0;
+#endif
 
 #ifdef USB_FULL_INIT
 static bool usb_host_present = false;
@@ -194,6 +197,10 @@ static inline void usb_handle_hotswap(long id)
 
 static inline bool usb_configure_drivers(int for_state)
 {
+#ifdef USB_ENABLE_AUDIO
+    // FIXME: doesn't seem to get set when loaded at boot...
+    usb_audio = global_settings.usb_audio;
+#endif
     switch(for_state)
     {
     case USB_POWERED:
@@ -207,6 +214,9 @@ static inline bool usb_configure_drivers(int for_state)
         usb_core_enable_driver(USB_DRIVER_HID, true);
 #endif /* USB_ENABLE_CHARGING_ONLY */
 #endif /* USB_ENABLE_HID */
+#ifdef USB_ENABLE_AUDIO
+        usb_core_enable_driver(USB_DRIVER_AUDIO, (usb_audio == 1) || (usb_audio == 2)); // while "always" or "only in charge-only mode"
+#endif /* USB_ENABLE_AUDIO */
 
 #ifdef USB_ENABLE_CHARGING_ONLY
         usb_core_enable_driver(USB_DRIVER_CHARGING_ONLY, true);
@@ -224,6 +234,9 @@ static inline bool usb_configure_drivers(int for_state)
 #ifdef USB_ENABLE_HID
         usb_core_enable_driver(USB_DRIVER_HID, usb_hid);
 #endif
+#ifdef USB_ENABLE_AUDIO
+        usb_core_enable_driver(USB_DRIVER_AUDIO, (usb_audio == 1) || (usb_audio == 3)); // while "always" or "only in mass-storage mode"
+#endif /* USB_ENABLE_AUDIO */
 #ifdef USB_ENABLE_CHARGING_ONLY
         usb_core_enable_driver(USB_DRIVER_CHARGING_ONLY, false);
 #endif
@@ -845,6 +858,13 @@ void usb_set_hid(bool enable)
 }
 #endif /* USB_ENABLE_HID */
 
+#ifdef USB_ENABLE_AUDIO
+void usb_set_audio(int value)
+{
+    usb_audio = value;
+}
+#endif /* USB_ENABLE_AUDIO */
+
 #ifdef HAVE_USB_POWER
 bool usb_powered_only(void)
 {

firmware/usbstack/usb_audio.h

@@ -0,0 +1,223 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id:  $
+ *
+ * Copyright (C) 2014 by Amaury Pouly
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#ifndef USB_AUDIO_H
+#define USB_AUDIO_H
+
+#include "usb_ch9.h"
+
+/*
+ * usb_audio_request_endpoints():
+ *
+ * Calls usb_core_request_endpoint() to request one IN and one OUT
+ * isochronous endpoint.
+ *
+ * Called by allocate_interfaces_and_endpoints().
+ *
+ * Returns -1 if either request fails, returns 0 if success.
+ *
+ * Also requests buffer allocations. If allocation fails,
+ * returns -1 so that the driver will be disabled by the USB core.
+ */
+int usb_audio_request_endpoints(struct usb_class_driver *);
+
+/*
+ * usb_audio_set_first_interface():
+ *
+ * Required function for the class driver.
+ *
+ * Called by allocate_interfaces_and_endpoints() to
+ * tell the class driver what its first interface number is.
+ * Returns the number of the interface available for the next
+ * class driver to use.
+ *
+ * We need 2 interfaces, AudioControl and AudioStreaming.
+ * Return interface+2.
+ */
+int usb_audio_set_first_interface(int interface);
+
+/*
+ * usb_audio_get_config_descriptor():
+ *
+ * Required function for the class driver.
+ *
+ * Called by request_handler_device_get_descriptor(), which expects
+ * this function to fill *dest with the configuration descriptor for this
+ * class driver.
+ *
+ * Return the size of this descriptor in bytes.
+ */
+int usb_audio_get_config_descriptor(unsigned char *dest,int max_packet_size);
+
+/*
+ * usb_audio_init_connection():
+ *
+ * Called by usb_core_do_set_config() when the
+ * connection is ready to be used. Currently just sets
+ * the audio sample rate to default.
+ */
+void usb_audio_init_connection(void);
+
+/*
+ * usb_audio_init():
+ *
+ * Initialize the driver. Called by usb_core_init().
+ * Currently initializes the sampling frequency values available
+ * to the AudioStreaming interface.
+ */
+void usb_audio_init(void);
+
+/*
+ * usb_audio_disconnect():
+ *
+ * Called by usb_core_exit() AND usb_core_do_set_config().
+ *
+ * Indicates to the Class driver that the connection is no
+ * longer active. Currently just calls usb_audio_stop_playback().
+ */
+void usb_audio_disconnect(void);
+
+/*
+ * usb_audio_get_playing():
+ *
+ * Returns playing/not playing status of usbaudio.
+ */
+bool usb_audio_get_playing(void);
+
+/*
+ * usb_audio_get_alloc_failed():
+ *
+ * Return whether the buffer allocation succeeded (0)
+ * or failed (1).
+ */
+bool usb_audio_get_alloc_failed(void);
+
+/*
+ * usb_audio_transfer_complete():
+ *
+ * Dummy function.
+ *
+ * The fast_transfer_complete() function needs to be used instead.
+ */
+void usb_audio_transfer_complete(int ep,int dir, int status, int length);
+
+/*
+ * usb_audio_fast_transfer_complete():
+ *
+ * Called by usb_core_transfer_complete().
+ * The normal transfer complete handler system is too slow to deal with
+ * ISO data at the rate required, so this is required.
+ *
+ * Return true if the transfer is handled, false otherwise.
+ */
+bool usb_audio_fast_transfer_complete(int ep,int dir, int status, int length);
+
+/*
+ * usb_audio_control_request():
+ *
+ * Called by control_request_handler_drivers().
+ * Pass control requests down to the appropriate functions.
+ *
+ * Return true if this driver handles the request, false otherwise.
+ */
+bool usb_audio_control_request(struct usb_ctrlrequest* req, void* reqdata, unsigned char* dest);
+
+/*
+ * usb_audio_set_interface():
+ *
+ * Called by control_request_handler_drivers().
+ * Deal with changing the interface between control and streaming.
+ *
+ * Return 0 for success, -1 otherwise.
+ */
+int usb_audio_set_interface(int intf, int alt);
+
+/*
+ * usb_audio_get_interface():
+ *
+ * Called by control_request_handler_drivers().
+ * Get the alternate of the given interface.
+ *
+ * Return the alternate of the given interface, -1 if unknown.
+ */
+int usb_audio_get_interface(int intf);
+
+/*
+ * usb_audio_get_playback_sampling_frequency():
+ *
+ * Return the sample rate currently set.
+ */
+unsigned long usb_audio_get_playback_sampling_frequency(void);
+
+/*
+ * usb_audio_get_main_intf():
+ *
+ * Return the main usb interface
+ */
+int usb_audio_get_main_intf(void);
+
+/*
+ * usb_audio_get_alt_intf():
+ *
+ * Return the alternate usb interface
+ */
+int usb_audio_get_alt_intf(void);
+
+/*
+ * usb_audio_get_out_ep():
+ *
+ * Return the out (to device) endpoint
+ */
+unsigned int usb_audio_get_out_ep(void);
+
+/*
+ * usb_audio_get_in_ep():
+ *
+ * Return the in (to host) endpoint
+ */
+unsigned int usb_audio_get_in_ep(void);
+
+/*
+ * usb_audio_get_prebuffering():
+ *
+ * Return number of buffers filled ahead of playback
+ */
+int usb_audio_get_prebuffering(void);
+
+/*
+ * usb_audio_get_underflow():
+ *
+ * Return whether playback is in "underflow" state
+ */
+bool usb_audio_get_underflow(void);
+
+/*
+ * usb_audio_get_overflow():
+ *
+ * Return whether usb is in "overflow" state
+ */
+bool usb_audio_get_overflow(void);
+
+/*
+ * usb_audio_get_cur_volume():
+ *
+ * Return current audio volume in db
+ */
+int usb_audio_get_cur_volume(void);
+
+#endif

firmware/usbstack/usb_audio_def.h

@@ -0,0 +1,233 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id:  $
+ *
+ * Copyright (C) 2010 by Amaury Pouly
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+/* Parts of this file are based on Frank Gevaerts work and on audio.h from linux */
+
+#ifndef USB_AUDIO_DEF_H
+#define USB_AUDIO_DEF_H
+
+#include "usb_ch9.h"
+
+#define USB_SUBCLASS_AUDIO_CONTROL      1
+#define USB_SUBCLASS_AUDIO_STREAMING    2
+
+#define USB_AC_HEADER           1
+#define USB_AC_INPUT_TERMINAL   2
+#define USB_AC_OUTPUT_TERMINAL  3
+#define USB_AC_MIXER_UNIT       4
+#define USB_AC_SELECTOR_UNIT    5
+#define USB_AC_FEATURE_UNIT     6
+#define USB_AC_PROCESSING_UNIT  8
+#define USB_AC_EXTENSION_UNIT   9
+
+#define USB_AS_GENERAL      1
+#define USB_AS_FORMAT_TYPE  2
+
+#define USB_AC_CHANNEL_LEFT_FRONT   0x1
+#define USB_AC_CHANNEL_RIGHT_FRONT  0x2
+
+#define USB_AC_CHANNELS_LEFT_RIGHT_FRONT    (USB_AC_CHANNEL_LEFT_FRONT | USB_AC_CHANNEL_RIGHT_FRONT)
+
+/* usb audio data structures */
+struct usb_ac_header {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType; /* USB_DT_CS_INTERFACE */
+    uint8_t  bDescriptorSubType; /* USB_AC_HEADER */
+    uint16_t  bcdADC;
+    uint16_t wTotalLength;
+    uint8_t  bInCollection;
+    uint8_t  baInterfaceNr[];
+} __attribute__ ((packed));
+
+#define USB_AC_SIZEOF_HEADER(n)         (8 + (n))
+
+#define USB_AC_TERMINAL_UNDEFINED       0x100
+#define USB_AC_TERMINAL_STREAMING       0x101
+#define USB_AC_TERMINAL_VENDOR_SPEC     0x1ff
+
+#define USB_AC_EXT_TERMINAL_UNDEFINED   0x600
+#define USB_AC_EXT_TERMINAL_ANALOG      0x601
+#define USB_AC_EXT_TERMINAL_DIGITAL     0x602
+#define USB_AC_EXT_TERMINAL_LINE        0x603
+#define USB_AC_EXT_TERMINAL_LEGACY      0x604
+#define USB_AC_EXT_TERMINAL_SPDIF       0x605
+#define USB_AC_EXT_TERMINAL_1394_DA     0x606
+#define USB_AC_EXT_TERMINAL_1394_DV     0x607
+
+#define USB_AC_EMB_MINIDISK     0x706
+#define USB_AC_EMB_RADIO_RECV   0x710
+
+#define USB_AC_INPUT_TERMINAL_UNDEFINED             0x200
+#define USB_AC_INPUT_TERMINAL_MICROPHONE            0x201
+#define USB_AC_INPUT_TERMINAL_DESKTOP_MICROPHONE    0x202
+#define USB_AC_INPUT_TERMINAL_PERSONAL_MICROPHONE   0x203
+#define USB_AC_INPUT_TERMINAL_OMNI_DIR_MICROPHONE   0x204
+#define USB_AC_INPUT_TERMINAL_MICROPHONE_ARRAY      0x205
+#define USB_AC_INPUT_TERMINAL_PROC_MICROPHONE_ARRAY 0x206
+
+struct usb_ac_input_terminal {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType; /* USB_DT_CS_INTERFACE */
+    uint8_t  bDescriptorSubType; /* USB_AC_INPUT_TERMINAL */
+    uint8_t  bTerminalId;
+    uint16_t wTerminalType; /* USB_AC_INPUT_TERMINAL_* */
+    uint8_t  bAssocTerminal;
+    uint8_t  bNrChannels;
+    uint16_t wChannelConfig;
+    uint8_t  iChannelNames;
+    uint8_t  iTerminal;
+} __attribute__ ((packed));
+
+#define USB_AC_OUTPUT_TERMINAL_UNDEFINED                    0x300
+#define USB_AC_OUTPUT_TERMINAL_SPEAKER                      0x301
+#define USB_AC_OUTPUT_TERMINAL_HEADPHONES                   0x302
+#define USB_AC_OUTPUT_TERMINAL_HEAD_MOUNTED_DISPLAY_AUDIO   0x303
+#define USB_AC_OUTPUT_TERMINAL_DESKTOP_SPEAKER              0x304
+#define USB_AC_OUTPUT_TERMINAL_ROOM_SPEAKER                 0x305
+#define USB_AC_OUTPUT_TERMINAL_COMMUNICATION_SPEAKER        0x306
+#define USB_AC_OUTPUT_TERMINAL_LOW_FREQ_EFFECTS_SPEAKER     0x307
+
+struct usb_ac_output_terminal {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType; /* USB_DT_CS_INTERFACE */
+    uint8_t  bDescriptorSubType; /* USB_AC_OUTPUT_TERMINAL */
+    uint8_t  bTerminalId;
+    uint16_t wTerminalType; /* USB_AC_OUTPUT_TERMINAL_* */
+    uint8_t  bAssocTerminal;
+    uint8_t  bSourceId;
+    uint8_t  iTerminal;
+} __attribute__ ((packed));
+
+#define USB_AC_FU_CONTROL_UNDEFINED 0x00
+#define USB_AC_MUTE_CONTROL         0x01
+#define USB_AC_VOLUME_CONTROL       0x02
+#define USB_AC_BASS_CONTROL         0x03
+#define USB_AC_MID_CONTROL          0x04
+#define USB_AC_TREBLE_CONTROL       0x05
+#define USB_AC_EQUALIZER_CONTROL    0x06
+#define USB_AC_AUTO_GAIN_CONTROL    0x07
+#define USB_AC_DELAY_CONTROL        0x08
+#define USB_AC_BASS_BOOST_CONTROL   0x09
+#define USB_AC_LOUDNESS_CONTROL     0x0a
+
+#define USB_AC_FU_MUTE          (1 << (USB_AC_MUTE_CONTROL - 1))
+#define USB_AC_FU_VOLUME        (1 << (USB_AC_VOLUME_CONTROL - 1))
+#define USB_AC_FU_BASS          (1 << (USB_AC_BASS_CONTROL - 1))
+#define USB_AC_FU_MID           (1 << (USB_AC_MID_CONTROL - 1))
+#define USB_AC_FU_TREBLE        (1 << (USB_AC_TREBLE_CONTROL - 1))
+#define USB_AC_FU_EQUILIZER     (1 << (USB_AC_EQUALIZER_CONTROL - 1))
+#define USB_AC_FU_AUTO_GAIN     (1 << (USB_AC_AUTO_GAIN_CONTROL - 1))
+#define USB_AC_FU_DELAY         (1 << (USB_AC_DELAY_CONTROL - 1))
+#define USB_AC_FU_BASS_BOOST    (1 << (USB_AC_BASS_BOOST_CONTROL - 1))
+#define USB_AC_FU_LOUDNESS      (1 << (USB_AC_LOUDNESS_CONTROL - 1))
+
+#define DEFINE_USB_AC_FEATURE_UNIT(n,ch) \
+struct usb_ac_feature_unit_##n##_##ch { \
+    uint8_t   bLength; \
+    uint8_t   bDescriptorType; /* USB_DT_CS_INTERFACE */ \
+    uint8_t   bDescriptorSubType; /* USB_AC_FEATURE_UNIT */ \
+    uint8_t   bUnitId; \
+    uint8_t   bSourceId; \
+    uint8_t   bControlSize; \
+    uint##n##_t bmaControls[ch + 1]; /* FU_* ORed*/ \
+    uint8_t   iFeature; \
+} __attribute__ ((packed));
+
+#define USB_AC_SET_REQ  0x00
+#define USB_AC_GET_REQ  0x80
+
+#define USB_AC_CUR_REQ  0x1
+#define USB_AC_MIN_REQ  0x2
+#define USB_AC_MAX_REQ  0x3
+#define USB_AC_RES_REQ  0x4
+#define USB_AC_MEM_REQ  0x5
+
+#define USB_AC_SET_CUR  (USB_AC_SET_REQ | USB_AC_CUR_REQ)
+#define USB_AC_GET_CUR  (USB_AC_GET_REQ | USB_AC_CUR_REQ)
+#define USB_AC_SET_MIN  (USB_AC_SET_REQ | USB_AC_MIN_REQ)
+#define USB_AC_GET_MIN  (USB_AC_GET_REQ | USB_AC_MIN_REQ)
+#define USB_AC_SET_MAX  (USB_AC_SET_REQ | USB_AC_MAX_REQ)
+#define USB_AC_GET_MAX  (USB_AC_GET_REQ | USB_AC_MAX_REQ)
+#define USB_AC_SET_RES  (USB_AC_SET_REQ | USB_AC_RES_REQ)
+#define USB_AC_GET_RES  (USB_AC_GET_REQ | USB_AC_RES_REQ)
+#define USB_AC_SET_MEM  (USB_AC_SET_REQ | USB_AC_MEM_REQ)
+#define USB_AC_GET_MEM  (USB_AC_GET_REQ | USB_AC_MEM_REQ)
+#define USB_AC_GET_STAT 0xff
+
+#define USB_AS_FORMAT_TYPE_UNDEFINED    0x0
+#define USB_AS_FORMAT_TYPE_I            0x1
+#define USB_AS_FORMAT_TYPE_II           0x2
+#define USB_AS_FORMAT_TYPE_III          0x3
+
+struct usb_as_interface {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType; /* USB_DT_CS_INTERFACE */
+    uint8_t  bDescriptorSubType; /* USB_AS_GENERAL */
+    uint8_t  bTerminalLink;
+    uint8_t  bDelay;
+    uint16_t wFormatTag;
+} __attribute__ ((packed));
+
+#define USB_AS_EP_GENERAL   0x01
+
+#define USB_AS_EP_CS_SAMPLING_FREQ_CTL  0x01
+#define USB_AS_EP_CS_PITCH_CTL          0x02
+
+struct usb_iso_audio_endpoint_descriptor {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType;
+
+    uint8_t  bEndpointAddress;
+    uint8_t  bmAttributes;
+    uint16_t wMaxPacketSize;
+    uint8_t  bInterval;
+    uint8_t  bRefresh;
+    uint8_t  bSynchAddress;
+} __attribute__ ((packed));
+
+struct usb_as_iso_endpoint {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType; /* USB_DT_CS_ENDPOINT */
+    uint8_t  bDescriptorSubType; /* USB_AS_EP_GENERAL */
+    uint8_t  bmAttributes;
+    uint8_t  bLockDelayUnits;
+    uint16_t wLockDelay;
+} __attribute__ ((packed));
+
+#define USB_AS_FORMAT_TYPE_I_UNDEFINED  0x0
+#define USB_AS_FORMAT_TYPE_I_PCM        0x1
+#define USB_AS_FORMAT_TYPE_I_PCM8       0x2
+#define USB_AS_FORMAT_TYPE_I_IEEE_FLOAT 0x3
+#define USB_AS_FORMAT_TYPE_I_ALAW       0x4
+#define USB_AS_FORMAT_TYPE_I_MULAW      0x5
+
+struct usb_as_format_type_i_discrete {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType;       /* USB_DT_CS_INTERFACE */
+    uint8_t  bDescriptorSubType;    /* USB_AS_FORMAT_TYPE */
+    uint8_t  bFormatType;   /* USB_AS_FORMAT_TYPE_I */
+    uint8_t  bNrChannels;
+    uint8_t  bSubframeSize;
+    uint8_t  bBitResolution;
+    uint8_t  bSamFreqType; /* Number of discrete frequencies */
+    uint8_t  tSamFreq[][3];
+} __attribute__ ((packed));
+
+#define USB_AS_SIZEOF_FORMAT_TYPE_I_DISCRETE(n) (8 + (n * 3))
+
+#endif /* USB_AUDIO_DEF_H */

firmware/usbstack/usb_class_driver.h

@@ -74,7 +74,16 @@ struct usb_class_driver {
     /* Tells the driver that a usb transfer has been completed. Note that "dir"
        is relative to the host
        Optional function */
-    void (*transfer_complete)(int ep,int dir, int status, int length);
+    void (*transfer_complete)(int ep, int dir, int status, int length);
+
+    /* Similar to transfer_complete but called directly instead of going through
+     * the usb queue. Since it might be called in an interrupt context,
+     * processing should be kept to a minimum. This is mainly intended for
+     * isochronous transfers.
+     * The function must return true if it handled the completion, and false
+     * otherwise so that it is dispatched to the normal handler
+     * Optional function */
+    bool (*fast_transfer_complete)(int ep, int dir, int status, int length);
 
     /* Tells the driver that a control request has come in. If the driver is
        able to handle it, it should ack the request, and return true. Otherwise
@@ -88,6 +97,16 @@ struct usb_class_driver {
        Optional function */
     void (*notify_hotswap)(int volume, bool inserted);
 #endif
+
+    /* Tells the driver to select an alternate setting for a specific interface.
+     * Returns 0 on success and -1 on error.
+     * Mandatory function if alternate interface support is needed */
+    int (*set_interface)(int interface, int alt_setting);
+
+    /* Asks the driver what is the current alternate setting for a specific interface.
+     * Returns value on success and -1 on error.
+     * Mandatory function if alternate interface support is needed */
+    int (*get_interface)(int interface);
 };
 
 #define PACK_DATA(dest, data) pack_data(dest, &(data), sizeof(data))

firmware/usbstack/usb_core.c

@@ -48,6 +48,11 @@
 #include "usb_hid.h"
 #endif
 
+#ifdef USB_ENABLE_AUDIO
+#include "usb_audio.h"
+#include "usb_audio_def.h" // DEBUG
+#endif
+
 /* TODO: Move target-specific stuff somewhere else (serial number reading) */
 
 #if defined(IPOD_ARCH) && defined(CPU_PP)
@@ -166,12 +171,14 @@ static int usb_no_host_callback(struct timeout *tmo)
 static int usb_core_num_interfaces;
 
 typedef void (*completion_handler_t)(int ep, int dir, int status, int length);
+typedef bool (*fast_completion_handler_t)(int ep, int dir, int status, int length);
 typedef bool (*control_handler_t)(struct usb_ctrlrequest* req, void* reqdata,
     unsigned char* dest);
 
 static struct
 {
     completion_handler_t completion_handler[2];
+    fast_completion_handler_t fast_completion_handler[2];
     control_handler_t control_handler[2];
     struct usb_transfer_completion_event_data completion_event[2];
 } ep_data[USB_NUM_ENDPOINTS];
@@ -254,6 +261,28 @@ static struct usb_class_driver drivers[USB_NUM_DRIVERS] =
 #endif
     },
 #endif
+#ifdef USB_ENABLE_AUDIO
+    [USB_DRIVER_AUDIO] = {
+        .enabled = false,
+        .needs_exclusive_storage = false,
+        .first_interface = 0,
+        .last_interface = 0,
+        .request_endpoints = usb_audio_request_endpoints,
+        .set_first_interface = usb_audio_set_first_interface,
+        .get_config_descriptor = usb_audio_get_config_descriptor,
+        .init_connection = usb_audio_init_connection,
+        .init = usb_audio_init,
+        .disconnect = usb_audio_disconnect,
+        .transfer_complete = usb_audio_transfer_complete,
+        .fast_transfer_complete = usb_audio_fast_transfer_complete,
+        .control_request = usb_audio_control_request,
+#ifdef HAVE_HOTSWAP
+        .notify_hotswap = NULL,
+#endif
+        .set_interface = usb_audio_set_interface,
+        .get_interface = usb_audio_get_interface,
+    },
+#endif
 };
 
 #ifdef USB_LEGACY_CONTROL_API
@@ -542,6 +571,7 @@ int usb_core_request_endpoint(int type, int dir, struct usb_class_driver* drv)
     ep = EP_NUM(ret);
 
     ep_data[ep].completion_handler[dir] = drv->transfer_complete;
+    ep_data[ep].fast_completion_handler[dir] = drv->fast_transfer_complete;
     ep_data[ep].control_handler[dir] = drv->control_request;
 
     return ret;
@@ -598,16 +628,46 @@ static void control_request_handler_drivers(struct usb_ctrlrequest* req, void* r
         if(drivers[i].enabled &&
                 drivers[i].control_request &&
                 drivers[i].first_interface <= interface &&
-                drivers[i].last_interface > interface)
+                drivers[i].last_interface > interface) {
-        {
+            /* Check for SET_INTERFACE and GET_INTERFACE */
+            if((req->bRequestType & USB_RECIP_MASK) == USB_RECIP_INTERFACE &&
+                    (req->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
+
+                if(req->bRequest == USB_REQ_SET_INTERFACE) {
+                    logf("usb_core: SET INTERFACE 0x%x 0x%x", req->wValue, req->wIndex);
+                    if(drivers[i].set_interface &&
+                            drivers[i].set_interface(req->wIndex, req->wValue) >= 0) {
+
+                        usb_drv_control_response(USB_CONTROL_ACK, NULL, 0);
+                        handled = true;
+                    }
+                    break;
+                }
+                else if(req->bRequest == USB_REQ_GET_INTERFACE) {
+                    int alt = -1;
+                    logf("usb_core: GET INTERFACE 0x%x", req->wIndex);
+
+                    if(drivers[i].get_interface)
+                        alt = drivers[i].get_interface(req->wIndex);
+
+                    if(alt >= 0 && alt < 255) {
+                        response_data[0] = alt;
+                        usb_drv_control_response(USB_CONTROL_ACK, response_data, 1);
+                        handled = true;
+                    }
+                    break;
+                }
+                /* fallback */
+            }
+
             handled = drivers[i].control_request(req, reqdata, response_data);
-            if(handled)
+            break; /* no other driver can handle it because it's interface specific */
-                break;
         }
     }
     if(!handled) {
         /* nope. flag error */
-        logf("bad req:desc %d:%d", req->bRequest, req->wValue >> 8);
+        logf("bad req 0x%x:0x%x:0x%x:0x%x:0x%x", req->bRequestType,req->bRequest,
+            req->wValue, req->wIndex, req->wLength);
         usb_drv_control_response(USB_CONTROL_STALL, NULL, 0);
     }
 }
@@ -804,13 +864,9 @@ static void request_handler_interface_standard(struct usb_ctrlrequest* req, void
     {
         case USB_REQ_SET_INTERFACE:
             logf("usb_core: SET_INTERFACE");
-            usb_drv_control_response(USB_CONTROL_ACK, NULL, 0);
-            break;
-
         case USB_REQ_GET_INTERFACE:
-            logf("usb_core: GET_INTERFACE");
+            control_request_handler_drivers(req, reqdata);
-            response_data[0] = 0;
+            break;
-            usb_drv_control_response(USB_CONTROL_ACK, response_data, 1);
             break;
         case USB_REQ_GET_STATUS:
             response_data[0] = 0;
@@ -860,7 +916,8 @@ static void request_handler_endpoint_drivers(struct usb_ctrlrequest* req, void*
 
     if(!handled) {
         /* nope. flag error */
-        logf("usb bad req %d", req->bRequest);
+        logf("bad req 0x%x:0x%x:0x%x:0x%x:0x%x", req->bRequestType,req->bRequest,
+             req->wValue, req->wIndex, req->wLength);
         usb_drv_control_response(USB_CONTROL_STALL, NULL, 0);
     }
 }
@@ -970,6 +1027,10 @@ void usb_core_transfer_complete(int endpoint, int dir, int status, int length)
 {
     struct usb_transfer_completion_event_data* completion_event =
         &ep_data[endpoint].completion_event[EP_DIR(dir)];
+    /* Fast notification */
+    fast_completion_handler_t handler = ep_data[endpoint].fast_completion_handler[EP_DIR(dir)];
+    if(handler != NULL && handler(endpoint, dir, status, length))
+        return; /* do not dispatch to the queue if handled */
 
     void* data0 = NULL;
     void* data1 = NULL;