USB: gadget: add USB Audio Gadget driver

Funtions added:
 - setup all the USB audio class device descriptors
 - handle class specific setup request
 - receive data from USB host by ISO transfer
 - play audio data by ALSA sound card
 - open and setup playback PCM interface
 - set default playback PCM parameters
 - provide playback functions for USB audio driver
 - provide PCM parameters set/get functions

Test on:
 - Host: Ubuntu 8.10, kernel 2.6.27
 - Gadget: EZKIT-BF548 with ASoC AD1980 codec

Todo:
 - add real Mute control code
 - add real Volume control code
 - maybe find another way to replace dynamic buffer handling
   with static buffer allocation
 - test on Windows system
 - provide control interface to handle mute/volume control
 - provide capture interface in the future
 - test on BF527, other USB device controler and other audio codec

Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 302 insertions, 0 deletions

diff --git a/drivers/usb/gadget/audio.c b/drivers/usb/gadget/audio.c
new file mode 100644
index 000000000000..94de7e864614
--- /dev/null
+++ b/drivers/usb/gadget/audio.c
@@ -0,0 +1,302 @@
+/*
+ * audio.c -- Audio gadget driver
+ *
+ * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
+ * Copyright (C) 2008 Analog Devices, Inc
+ *
+ * Enter bugs at http://blackfin.uclinux.org/
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+/* #define VERBOSE_DEBUG */
+
+#include <linux/kernel.h>
+#include <linux/utsname.h>
+
+#include "u_audio.h"
+
+#define DRIVER_DESC             "Linux USB Audio Gadget"
+#define DRIVER_VERSION          "Dec 18, 2008"
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * Kbuild is not very cooperative with respect to linking separately
+ * compiled library objects into one module.  So for now we won't use
+ * separate compilation ... ensuring init/exit sections work to shrink
+ * the runtime footprint, and giving us at least some parts of what
+ * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
+ */
+#include "composite.c"
+#include "usbstring.c"
+#include "config.c"
+#include "epautoconf.c"
+
+#include "u_audio.c"
+#include "f_audio.c"
+
+/*-------------------------------------------------------------------------*/
+
+/* DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
+ * Instead:  allocate your own, using normal USB-IF procedures.
+ */
+
+/* Thanks to NetChip Technologies for donating this product ID. */
+#define AUDIO_VENDOR_NUM                0x0525  /* NetChip */
+#define AUDIO_PRODUCT_NUM               0xa4a1  /* Linux-USB Audio Gadget */
+
+/*-------------------------------------------------------------------------*/
+
+static struct usb_device_descriptor device_desc = {
+        .bLength =              sizeof device_desc,
+        .bDescriptorType =      USB_DT_DEVICE,
+
+        .bcdUSB =               __constant_cpu_to_le16(0x200),
+
+        .bDeviceClass =         USB_CLASS_PER_INTERFACE,
+        .bDeviceSubClass =      0,
+        .bDeviceProtocol =      0,
+        /* .bMaxPacketSize0 = f(hardware) */
+
+        /* Vendor and product id defaults change according to what configs
+         * we support.  (As does bNumConfigurations.)  These values can
+         * also be overridden by module parameters.
+         */
+        .idVendor =             __constant_cpu_to_le16(AUDIO_VENDOR_NUM),
+        .idProduct =            __constant_cpu_to_le16(AUDIO_PRODUCT_NUM),
+        /* .bcdDevice = f(hardware) */
+        /* .iManufacturer = DYNAMIC */
+        /* .iProduct = DYNAMIC */
+        /* NO SERIAL NUMBER */
+        .bNumConfigurations =   1,
+};
+
+static struct usb_otg_descriptor otg_descriptor = {
+        .bLength =              sizeof otg_descriptor,
+        .bDescriptorType =      USB_DT_OTG,
+
+        /* REVISIT SRP-only hardware is possible, although
+         * it would not be called "OTG" ...
+         */
+        .bmAttributes =         USB_OTG_SRP | USB_OTG_HNP,
+};
+
+static const struct usb_descriptor_header *otg_desc[] = {
+        (struct usb_descriptor_header *) &otg_descriptor,
+        NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+/**
+ * Handle USB audio endpoint set/get command in setup class request
+ */
+
+static int audio_set_endpoint_req(struct usb_configuration *c,
+                const struct usb_ctrlrequest *ctrl)
+{
+        struct usb_composite_dev *cdev = c->cdev;
+        int                     value = -EOPNOTSUPP;
+        u16                     ep = le16_to_cpu(ctrl->wIndex);
+        u16                     len = le16_to_cpu(ctrl->wLength);
+        u16                     w_value = le16_to_cpu(ctrl->wValue);
+
+        DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
+                        ctrl->bRequest, w_value, len, ep);
+
+        switch (ctrl->bRequest) {
+        case SET_CUR:
+                value = 0;
+                break;
+
+        case SET_MIN:
+                break;
+
+        case SET_MAX:
+                break;
+
+        case SET_RES:
+                break;
+
+        case SET_MEM:
+                break;
+
+        default:
+                break;
+        }
+
+        return value;
+}
+
+static int audio_get_endpoint_req(struct usb_configuration *c,
+                const struct usb_ctrlrequest *ctrl)
+{
+        struct usb_composite_dev *cdev = c->cdev;
+        int value = -EOPNOTSUPP;
+        u8 ep = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
+        u16 len = le16_to_cpu(ctrl->wLength);
+        u16 w_value = le16_to_cpu(ctrl->wValue);
+
+        DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
+                        ctrl->bRequest, w_value, len, ep);
+
+        switch (ctrl->bRequest) {
+        case GET_CUR:
+        case GET_MIN:
+        case GET_MAX:
+        case GET_RES:
+                value = 3;
+                break;
+        case GET_MEM:
+                break;
+        default:
+                break;
+        }
+
+        return value;
+}
+
+static int
+audio_setup(struct usb_configuration *c, const struct usb_ctrlrequest *ctrl)
+{
+        struct usb_composite_dev *cdev = c->cdev;
+        struct usb_request *req = cdev->req;
+        int value = -EOPNOTSUPP;
+        u16 w_index = le16_to_cpu(ctrl->wIndex);
+        u16 w_value = le16_to_cpu(ctrl->wValue);
+        u16 w_length = le16_to_cpu(ctrl->wLength);
+
+        /* composite driver infrastructure handles everything except
+         * Audio class messages; interface activation uses set_alt().
+         */
+        switch (ctrl->bRequestType) {
+        case USB_AUDIO_SET_ENDPOINT:
+                value = audio_set_endpoint_req(c, ctrl);
+                break;
+
+        case USB_AUDIO_GET_ENDPOINT:
+                value = audio_get_endpoint_req(c, ctrl);
+                break;
+
+        default:
+                ERROR(cdev, "Invalid control req%02x.%02x v%04x i%04x l%d\n",
+                        ctrl->bRequestType, ctrl->bRequest,
+                        w_value, w_index, w_length);
+        }
+
+        /* respond with data transfer or status phase? */
+        if (value >= 0) {
+                DBG(cdev, "Audio req%02x.%02x v%04x i%04x l%d\n",
+                        ctrl->bRequestType, ctrl->bRequest,
+                        w_value, w_index, w_length);
+                req->zero = 0;
+                req->length = value;
+                value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+                if (value < 0)
+                        ERROR(cdev, "Audio response on err %d\n", value);
+        }
+
+        /* device either stalls (value < 0) or reports success */
+        return value;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int __init audio_do_config(struct usb_configuration *c)
+{
+        /* FIXME alloc iConfiguration string, set it in c->strings */
+
+        if (gadget_is_otg(c->cdev->gadget)) {
+                c->descriptors = otg_desc;
+                c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+        }
+
+        audio_bind_config(c);
+
+        return 0;
+}
+
+static struct usb_configuration audio_config_driver = {
+        .label                  = DRIVER_DESC,
+        .bind                   = audio_do_config,
+        .setup                  = audio_setup,
+        .bConfigurationValue    = 1,
+        /* .iConfiguration = DYNAMIC */
+        .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int __init audio_bind(struct usb_composite_dev *cdev)
+{
+        int                     gcnum;
+        int                     status;
+
+        gcnum = usb_gadget_controller_number(cdev->gadget);
+        if (gcnum >= 0)
+                device_desc.bcdDevice = cpu_to_le16(0x0300 | gcnum);
+        else {
+                ERROR(cdev, "controller '%s' not recognized; trying %s\n",
+                        cdev->gadget->name,
+                        audio_config_driver.label);
+                device_desc.bcdDevice =
+                        __constant_cpu_to_le16(0x0300 | 0x0099);
+        }
+
+        /* device descriptor strings: manufacturer, product */
+        snprintf(manufacturer, sizeof manufacturer, "%s %s with %s",
+                init_utsname()->sysname, init_utsname()->release,
+                cdev->gadget->name);
+        status = usb_string_id(cdev);
+        if (status < 0)
+                goto fail;
+        strings_dev[STRING_MANUFACTURER_IDX].id = status;
+        device_desc.iManufacturer = status;
+
+        status = usb_string_id(cdev);
+        if (status < 0)
+                goto fail;
+        strings_dev[STRING_PRODUCT_IDX].id = status;
+        device_desc.iProduct = status;
+
+        status = usb_add_config(cdev, &audio_config_driver);
+        if (status < 0)
+                goto fail;
+
+        INFO(cdev, "%s, version: %s\n", DRIVER_DESC, DRIVER_VERSION);
+        return 0;
+
+fail:
+        return status;
+}
+
+static int __exit audio_unbind(struct usb_composite_dev *cdev)
+{
+        return 0;
+}
+
+static struct usb_composite_driver audio_driver = {
+        .name           = "g_audio",
+        .dev            = &device_desc,
+        .strings        = audio_strings,
+        .bind           = audio_bind,
+        .unbind         = __exit_p(audio_unbind),
+};
+
+static int __init init(void)
+{
+        return usb_composite_register(&audio_driver);
+}
+module_init(init);
+
+static void __exit cleanup(void)
+{
+        usb_composite_unregister(&audio_driver);
+}
+module_exit(cleanup);
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR("Bryan Wu <cooloney@kernel.org>");
+MODULE_LICENSE("GPL");
+