Re: [PATCH v4 2/3] usb: gadget: f_uac2: split out audio core
From: Jassi Brar
Date: Mon May 22 2017 - 11:58:43 EST
On Thu, May 18, 2017 at 4:07 AM, Ruslan Bilovol
<ruslan.bilovol@xxxxxxxxx> wrote:
> Abstract the peripheral side ALSA sound card code from
> the f_uac2 function into a component that can be called
> by various functions, so the various flavors can be split
> apart and selectively reused.
>
> Visible changes:
> - add uac_params structure to pass audio paramteres for
> g_audio_setup
> - make ALSA sound card's name configurable
> - add [in/out]_ep_maxpsize
> - allocate snd_uac_chip structure during g_audio_setup
> - add u_audio_[start/stop]_[capture/playback] functions
>
> Signed-off-by: Ruslan Bilovol <ruslan.bilovol@xxxxxxxxx>
> ---
> drivers/usb/gadget/Kconfig | 4 +
> drivers/usb/gadget/function/Makefile | 1 +
> drivers/usb/gadget/function/f_uac2.c | 721 ++++------------------------------
> drivers/usb/gadget/function/u_audio.c | 661 +++++++++++++++++++++++++++++++
> drivers/usb/gadget/function/u_audio.h | 95 +++++
> drivers/usb/gadget/legacy/Kconfig | 1 +
> 6 files changed, 846 insertions(+), 637 deletions(-)
> create mode 100644 drivers/usb/gadget/function/u_audio.c
> create mode 100644 drivers/usb/gadget/function/u_audio.h
>
> diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
> index c164d6b..2ba0ace 100644
> --- a/drivers/usb/gadget/Kconfig
> +++ b/drivers/usb/gadget/Kconfig
> @@ -158,6 +158,9 @@ config USB_U_SERIAL
> config USB_U_ETHER
> tristate
>
> +config USB_U_AUDIO
> + tristate
> +
> config USB_F_SERIAL
> tristate
>
> @@ -381,6 +384,7 @@ config USB_CONFIGFS_F_UAC2
> depends on SND
> select USB_LIBCOMPOSITE
> select SND_PCM
> + select USB_U_AUDIO
> select USB_F_UAC2
> help
> This Audio function is compatible with USB Audio Class
> diff --git a/drivers/usb/gadget/function/Makefile b/drivers/usb/gadget/function/Makefile
> index cb8c225..b29f2ae 100644
> --- a/drivers/usb/gadget/function/Makefile
> +++ b/drivers/usb/gadget/function/Makefile
> @@ -32,6 +32,7 @@ usb_f_mass_storage-y := f_mass_storage.o storage_common.o
> obj-$(CONFIG_USB_F_MASS_STORAGE)+= usb_f_mass_storage.o
> usb_f_fs-y := f_fs.o
> obj-$(CONFIG_USB_F_FS) += usb_f_fs.o
> +obj-$(CONFIG_USB_U_AUDIO) += u_audio.o
> usb_f_uac1-y := f_uac1.o u_uac1.o
> obj-$(CONFIG_USB_F_UAC1) += usb_f_uac1.o
> usb_f_uac2-y := f_uac2.o
> diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
> index d4565b5..059a14a 100644
> --- a/drivers/usb/gadget/function/f_uac2.c
> +++ b/drivers/usb/gadget/function/f_uac2.c
> @@ -15,10 +15,7 @@
> #include <linux/usb/audio-v2.h>
> #include <linux/module.h>
>
> -#include <sound/core.h>
> -#include <sound/pcm.h>
> -#include <sound/pcm_params.h>
> -
> +#include "u_audio.h"
> #include "u_uac2.h"
>
> /*
> @@ -50,455 +47,23 @@
> #define UNFLW_CTRL 8
> #define OVFLW_CTRL 10
>
> -struct uac2_req {
> - struct uac2_rtd_params *pp; /* parent param */
> - struct usb_request *req;
> -};
> -
> -struct uac2_rtd_params {
> - struct snd_uac2_chip *uac2; /* parent chip */
> - bool ep_enabled; /* if the ep is enabled */
> - /* Size of the ring buffer */
> - size_t dma_bytes;
> - unsigned char *dma_area;
> -
> - struct snd_pcm_substream *ss;
> -
> - /* Ring buffer */
> - ssize_t hw_ptr;
> -
> - void *rbuf;
> -
> - size_t period_size;
> -
> - unsigned max_psize;
> - struct uac2_req *ureq;
> -
> - spinlock_t lock;
> -};
> -
> -struct snd_uac2_chip {
> - struct uac2_rtd_params p_prm;
> - struct uac2_rtd_params c_prm;
> -
> - struct snd_card *card;
> - struct snd_pcm *pcm;
> -
> - /* timekeeping for the playback endpoint */
> - unsigned int p_interval;
> - unsigned int p_residue;
> -
> - /* pre-calculated values for playback iso completion */
> - unsigned int p_pktsize;
> - unsigned int p_pktsize_residue;
> - unsigned int p_framesize;
> +struct f_uac2 {
> + struct g_audio g_audio;
> + u8 ac_intf, as_in_intf, as_out_intf;
> + u8 ac_alt, as_in_alt, as_out_alt; /* needed for get_alt() */
> };
>
> -#define BUFF_SIZE_MAX (PAGE_SIZE * 16)
> -#define PRD_SIZE_MAX PAGE_SIZE
> -#define MIN_PERIODS 4
> -
> -static struct snd_pcm_hardware uac2_pcm_hardware = {
> - .info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER
> - | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID
> - | SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,
> - .rates = SNDRV_PCM_RATE_CONTINUOUS,
> - .periods_max = BUFF_SIZE_MAX / PRD_SIZE_MAX,
> - .buffer_bytes_max = BUFF_SIZE_MAX,
> - .period_bytes_max = PRD_SIZE_MAX,
> - .periods_min = MIN_PERIODS,
> -};
> -
> -struct audio_dev {
> - u8 ac_intf, ac_alt;
> - u8 as_out_intf, as_out_alt;
> - u8 as_in_intf, as_in_alt;
> -
> - struct usb_ep *in_ep, *out_ep;
> - struct usb_function func;
> - struct usb_gadget *gadget;
> -
> - /* The ALSA Sound Card it represents on the USB-Client side */
> - struct snd_uac2_chip uac2;
> -};
> -
> -static inline
> -struct audio_dev *func_to_agdev(struct usb_function *f)
> +static inline struct f_uac2 *func_to_uac2(struct usb_function *f)
> {
> - return container_of(f, struct audio_dev, func);
> + return container_of(f, struct f_uac2, g_audio.func);
> }
>
> static inline
> -struct audio_dev *uac2_to_agdev(struct snd_uac2_chip *u)
> -{
> - return container_of(u, struct audio_dev, uac2);
> -}
> -
> -static inline
> -struct f_uac2_opts *agdev_to_uac2_opts(struct audio_dev *agdev)
> +struct f_uac2_opts *g_audio_to_uac2_opts(struct g_audio *agdev)
> {
> return container_of(agdev->func.fi, struct f_uac2_opts, func_inst);
> }
>
> -static inline
> -uint num_channels(uint chanmask)
> -{
> - uint num = 0;
> -
> - while (chanmask) {
> - num += (chanmask & 1);
> - chanmask >>= 1;
> - }
> -
> - return num;
> -}
> -
> -static void
> -agdev_iso_complete(struct usb_ep *ep, struct usb_request *req)
> -{
> - unsigned pending;
> - unsigned long flags;
> - unsigned int hw_ptr;
> - bool update_alsa = false;
> - int status = req->status;
> - struct uac2_req *ur = req->context;
> - struct snd_pcm_substream *substream;
> - struct uac2_rtd_params *prm = ur->pp;
> - struct snd_uac2_chip *uac2 = prm->uac2;
> -
> - /* i/f shutting down */
> - if (!prm->ep_enabled || req->status == -ESHUTDOWN)
> - return;
> -
> - /*
> - * We can't really do much about bad xfers.
> - * Afterall, the ISOCH xfers could fail legitimately.
> - */
> - if (status)
> - pr_debug("%s: iso_complete status(%d) %d/%d\n",
> - __func__, status, req->actual, req->length);
> -
> - substream = prm->ss;
> -
> - /* Do nothing if ALSA isn't active */
> - if (!substream)
> - goto exit;
> -
> - spin_lock_irqsave(&prm->lock, flags);
> -
> - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> - /*
> - * For each IN packet, take the quotient of the current data
> - * rate and the endpoint's interval as the base packet size.
> - * If there is a residue from this division, add it to the
> - * residue accumulator.
> - */
> - req->length = uac2->p_pktsize;
> - uac2->p_residue += uac2->p_pktsize_residue;
> -
> - /*
> - * Whenever there are more bytes in the accumulator than we
> - * need to add one more sample frame, increase this packet's
> - * size and decrease the accumulator.
> - */
> - if (uac2->p_residue / uac2->p_interval >= uac2->p_framesize) {
> - req->length += uac2->p_framesize;
> - uac2->p_residue -= uac2->p_framesize *
> - uac2->p_interval;
> - }
> -
> - req->actual = req->length;
> - }
> -
> - pending = prm->hw_ptr % prm->period_size;
> - pending += req->actual;
> - if (pending >= prm->period_size)
> - update_alsa = true;
> -
> - hw_ptr = prm->hw_ptr;
> - prm->hw_ptr = (prm->hw_ptr + req->actual) % prm->dma_bytes;
> -
> - spin_unlock_irqrestore(&prm->lock, flags);
> -
> - /* Pack USB load in ALSA ring buffer */
> - pending = prm->dma_bytes - hw_ptr;
> -
> - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> - if (unlikely(pending < req->actual)) {
> - memcpy(req->buf, prm->dma_area + hw_ptr, pending);
> - memcpy(req->buf + pending, prm->dma_area,
> - req->actual - pending);
> - } else {
> - memcpy(req->buf, prm->dma_area + hw_ptr, req->actual);
> - }
> - } else {
> - if (unlikely(pending < req->actual)) {
> - memcpy(prm->dma_area + hw_ptr, req->buf, pending);
> - memcpy(prm->dma_area, req->buf + pending,
> - req->actual - pending);
> - } else {
> - memcpy(prm->dma_area + hw_ptr, req->buf, req->actual);
> - }
> - }
> -
> -exit:
> - if (usb_ep_queue(ep, req, GFP_ATOMIC))
> - dev_err(uac2->card->dev, "%d Error!\n", __LINE__);
> -
> - if (update_alsa)
> - snd_pcm_period_elapsed(substream);
> -
> - return;
> -}
> -
> -static int
> -uac2_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
> -{
> - struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);
> - struct audio_dev *agdev = uac2_to_agdev(uac2);
> - struct f_uac2_opts *uac2_opts = agdev_to_uac2_opts(agdev);
> - struct uac2_rtd_params *prm;
> - unsigned long flags;
> - int err = 0;
> -
> - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> - prm = &uac2->p_prm;
> - else
> - prm = &uac2->c_prm;
> -
> - spin_lock_irqsave(&prm->lock, flags);
> -
> - /* Reset */
> - prm->hw_ptr = 0;
> -
> - switch (cmd) {
> - case SNDRV_PCM_TRIGGER_START:
> - case SNDRV_PCM_TRIGGER_RESUME:
> - prm->ss = substream;
> - break;
> - case SNDRV_PCM_TRIGGER_STOP:
> - case SNDRV_PCM_TRIGGER_SUSPEND:
> - prm->ss = NULL;
> - break;
> - default:
> - err = -EINVAL;
> - }
> -
> - spin_unlock_irqrestore(&prm->lock, flags);
> -
> - /* Clear buffer after Play stops */
> - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !prm->ss)
> - memset(prm->rbuf, 0, prm->max_psize * uac2_opts->req_number);
> -
> - return err;
> -}
> -
> -static snd_pcm_uframes_t uac2_pcm_pointer(struct snd_pcm_substream *substream)
> -{
> - struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);
> - struct uac2_rtd_params *prm;
> -
> - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> - prm = &uac2->p_prm;
> - else
> - prm = &uac2->c_prm;
> -
> - return bytes_to_frames(substream->runtime, prm->hw_ptr);
> -}
> -
> -static int uac2_pcm_hw_params(struct snd_pcm_substream *substream,
> - struct snd_pcm_hw_params *hw_params)
> -{
> - struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);
> - struct uac2_rtd_params *prm;
> - int err;
> -
> - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> - prm = &uac2->p_prm;
> - else
> - prm = &uac2->c_prm;
> -
> - err = snd_pcm_lib_malloc_pages(substream,
> - params_buffer_bytes(hw_params));
> - if (err >= 0) {
> - prm->dma_bytes = substream->runtime->dma_bytes;
> - prm->dma_area = substream->runtime->dma_area;
> - prm->period_size = params_period_bytes(hw_params);
> - }
> -
> - return err;
> -}
> -
> -static int uac2_pcm_hw_free(struct snd_pcm_substream *substream)
> -{
> - struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);
> - struct uac2_rtd_params *prm;
> -
> - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> - prm = &uac2->p_prm;
> - else
> - prm = &uac2->c_prm;
> -
> - prm->dma_area = NULL;
> - prm->dma_bytes = 0;
> - prm->period_size = 0;
> -
> - return snd_pcm_lib_free_pages(substream);
> -}
> -
> -static int uac2_pcm_open(struct snd_pcm_substream *substream)
> -{
> - struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);
> - struct snd_pcm_runtime *runtime = substream->runtime;
> - struct audio_dev *audio_dev;
> - struct f_uac2_opts *opts;
> - int p_ssize, c_ssize;
> - int p_srate, c_srate;
> - int p_chmask, c_chmask;
> -
> - audio_dev = uac2_to_agdev(uac2);
> - opts = container_of(audio_dev->func.fi, struct f_uac2_opts, func_inst);
> - p_ssize = opts->p_ssize;
> - c_ssize = opts->c_ssize;
> - p_srate = opts->p_srate;
> - c_srate = opts->c_srate;
> - p_chmask = opts->p_chmask;
> - c_chmask = opts->c_chmask;
> - uac2->p_residue = 0;
> -
> - runtime->hw = uac2_pcm_hardware;
> -
> - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> - spin_lock_init(&uac2->p_prm.lock);
> - runtime->hw.rate_min = p_srate;
> - switch (p_ssize) {
> - case 3:
> - runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
> - break;
> - case 4:
> - runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
> - break;
> - default:
> - runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
> - break;
> - }
> - runtime->hw.channels_min = num_channels(p_chmask);
> - runtime->hw.period_bytes_min = 2 * uac2->p_prm.max_psize
> - / runtime->hw.periods_min;
> - } else {
> - spin_lock_init(&uac2->c_prm.lock);
> - runtime->hw.rate_min = c_srate;
> - switch (c_ssize) {
> - case 3:
> - runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
> - break;
> - case 4:
> - runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
> - break;
> - default:
> - runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
> - break;
> - }
> - runtime->hw.channels_min = num_channels(c_chmask);
> - runtime->hw.period_bytes_min = 2 * uac2->c_prm.max_psize
> - / runtime->hw.periods_min;
> - }
> -
> - runtime->hw.rate_max = runtime->hw.rate_min;
> - runtime->hw.channels_max = runtime->hw.channels_min;
> -
> - snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
> -
> - return 0;
> -}
> -
> -/* ALSA cries without these function pointers */
> -static int uac2_pcm_null(struct snd_pcm_substream *substream)
> -{
> - return 0;
> -}
> -
> -static struct snd_pcm_ops uac2_pcm_ops = {
> - .open = uac2_pcm_open,
> - .close = uac2_pcm_null,
> - .ioctl = snd_pcm_lib_ioctl,
> - .hw_params = uac2_pcm_hw_params,
> - .hw_free = uac2_pcm_hw_free,
> - .trigger = uac2_pcm_trigger,
> - .pointer = uac2_pcm_pointer,
> - .prepare = uac2_pcm_null,
> -};
> -
> -static int snd_uac2_probe(struct audio_dev *audio_dev)
> -{
> - struct snd_uac2_chip *uac2 = &audio_dev->uac2;
> - struct snd_card *card;
> - struct snd_pcm *pcm;
> - struct f_uac2_opts *opts;
> - int err;
> - int p_chmask, c_chmask;
> -
> - opts = container_of(audio_dev->func.fi, struct f_uac2_opts, func_inst);
> - p_chmask = opts->p_chmask;
> - c_chmask = opts->c_chmask;
> -
> - /* Choose any slot, with no id */
> - err = snd_card_new(&audio_dev->gadget->dev,
> - -1, NULL, THIS_MODULE, 0, &card);
> - if (err < 0)
> - return err;
> -
> - uac2->card = card;
> -
> - /*
> - * Create first PCM device
> - * Create a substream only for non-zero channel streams
> - */
> - err = snd_pcm_new(uac2->card, "UAC2 PCM", 0,
> - p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
> - if (err < 0)
> - goto snd_fail;
> -
> - strcpy(pcm->name, "UAC2 PCM");
> - pcm->private_data = uac2;
> -
> - uac2->pcm = pcm;
> -
> - snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac2_pcm_ops);
> - snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac2_pcm_ops);
> -
> - strcpy(card->driver, "UAC2_Gadget");
> - strcpy(card->shortname, "UAC2_Gadget");
> - sprintf(card->longname, "UAC2_Gadget %i", card->dev->id);
> -
> - snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
> - snd_dma_continuous_data(GFP_KERNEL), 0, BUFF_SIZE_MAX);
> -
> - err = snd_card_register(card);
> -
> - if (!err)
> - return 0;
> -
> -snd_fail:
> - snd_card_free(card);
> -
> - uac2->pcm = NULL;
> - uac2->card = NULL;
> -
> - return err;
> -}
> -
> -static int snd_uac2_remove(struct audio_dev *audio_dev)
> -{
> - struct snd_card *card = audio_dev->uac2.card;
> -
> - if (card)
> - return snd_card_free(card);
> -
> - return 0;
> -}
> -
> -
> /* --------- USB Function Interface ------------- */
>
> enum {
> @@ -886,32 +451,6 @@ struct cntrl_range_lay3 {
> __u32 dRES;
> } __packed;
>
> -static inline void
> -free_ep(struct uac2_rtd_params *prm, struct usb_ep *ep)
> -{
> - struct snd_uac2_chip *uac2 = prm->uac2;
> - struct audio_dev *agdev = uac2_to_agdev(uac2);
> - struct f_uac2_opts *uac2_opts = agdev_to_uac2_opts(agdev);
> - int i;
> -
> - if (!prm->ep_enabled)
> - return;
> -
> - prm->ep_enabled = false;
> -
> - for (i = 0; i < uac2_opts->req_number; i++) {
> - if (prm->ureq[i].req) {
> - usb_ep_dequeue(ep, prm->ureq[i].req);
> - usb_ep_free_request(ep, prm->ureq[i].req);
> - prm->ureq[i].req = NULL;
> - }
> - }
> -
> - if (usb_ep_disable(ep))
> - dev_err(uac2->card->dev,
> - "%s:%d Error!\n", __func__, __LINE__);
> -}
> -
> static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> struct usb_endpoint_descriptor *ep_desc,
> unsigned int factor, bool is_playback)
> @@ -938,12 +477,11 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> static int
> afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
> {
> - struct audio_dev *agdev = func_to_agdev(fn);
> - struct snd_uac2_chip *uac2 = &agdev->uac2;
> + struct f_uac2 *uac2 = func_to_uac2(fn);
> + struct g_audio *agdev = func_to_g_audio(fn);
> struct usb_composite_dev *cdev = cfg->cdev;
> struct usb_gadget *gadget = cdev->gadget;
> struct device *dev = &gadget->dev;
> - struct uac2_rtd_params *prm;
> struct f_uac2_opts *uac2_opts;
> struct usb_string *us;
> int ret;
> @@ -990,8 +528,8 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> return ret;
> }
> std_ac_if_desc.bInterfaceNumber = ret;
> - agdev->ac_intf = ret;
> - agdev->ac_alt = 0;
> + uac2->ac_intf = ret;
> + uac2->ac_alt = 0;
>
> ret = usb_interface_id(cfg, fn);
> if (ret < 0) {
> @@ -1000,8 +538,8 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> }
> std_as_out_if0_desc.bInterfaceNumber = ret;
> std_as_out_if1_desc.bInterfaceNumber = ret;
> - agdev->as_out_intf = ret;
> - agdev->as_out_alt = 0;
> + uac2->as_out_intf = ret;
> + uac2->as_out_alt = 0;
>
> ret = usb_interface_id(cfg, fn);
> if (ret < 0) {
> @@ -1010,8 +548,8 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> }
> std_as_in_if0_desc.bInterfaceNumber = ret;
> std_as_in_if1_desc.bInterfaceNumber = ret;
> - agdev->as_in_intf = ret;
> - agdev->as_in_alt = 0;
> + uac2->as_in_intf = ret;
> + uac2->as_in_alt = 0;
>
> agdev->out_ep = usb_ep_autoconfig(gadget, &fs_epout_desc);
> if (!agdev->out_ep) {
> @@ -1025,15 +563,17 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> return ret;
> }
>
> - uac2->p_prm.uac2 = uac2;
> - uac2->c_prm.uac2 = uac2;
> -
> /* Calculate wMaxPacketSize according to audio bandwidth */
> set_ep_max_packet_size(uac2_opts, &fs_epin_desc, 1000, true);
> set_ep_max_packet_size(uac2_opts, &fs_epout_desc, 1000, false);
> set_ep_max_packet_size(uac2_opts, &hs_epin_desc, 8000, true);
> set_ep_max_packet_size(uac2_opts, &hs_epout_desc, 8000, false);
>
> + agdev->in_ep_maxpsize = max(fs_epin_desc.wMaxPacketSize,
> + hs_epin_desc.wMaxPacketSize);
> + agdev->out_ep_maxpsize = max(fs_epout_desc.wMaxPacketSize,
> + hs_epout_desc.wMaxPacketSize);
> +
> hs_epout_desc.bEndpointAddress = fs_epout_desc.bEndpointAddress;
> hs_epin_desc.bEndpointAddress = fs_epin_desc.bEndpointAddress;
>
> @@ -1044,46 +584,18 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
>
> agdev->gadget = gadget;
>
> - prm = &agdev->uac2.c_prm;
> - prm->max_psize = hs_epout_desc.wMaxPacketSize;
> - prm->ureq = kcalloc(uac2_opts->req_number, sizeof(struct uac2_req),
> - GFP_KERNEL);
> - if (!prm->ureq) {
> - ret = -ENOMEM;
> - goto err_free_descs;
> - }
> - prm->rbuf = kcalloc(uac2_opts->req_number, prm->max_psize, GFP_KERNEL);
> - if (!prm->rbuf) {
> - prm->max_psize = 0;
> - ret = -ENOMEM;
> - goto err_free_descs;
> - }
> -
> - prm = &agdev->uac2.p_prm;
> - prm->max_psize = hs_epin_desc.wMaxPacketSize;
> - prm->ureq = kcalloc(uac2_opts->req_number, sizeof(struct uac2_req),
> - GFP_KERNEL);
> - if (!prm->ureq) {
> - ret = -ENOMEM;
> - goto err_free_descs;
> - }
> - prm->rbuf = kcalloc(uac2_opts->req_number, prm->max_psize, GFP_KERNEL);
> - if (!prm->rbuf) {
> - prm->max_psize = 0;
> - ret = -ENOMEM;
> - goto err_no_memory;
> - }
> -
> - ret = snd_uac2_probe(agdev);
> + agdev->params.p_chmask = uac2_opts->p_chmask;
> + agdev->params.p_srate = uac2_opts->p_srate;
> + agdev->params.p_ssize = uac2_opts->p_ssize;
> + agdev->params.c_chmask = uac2_opts->c_chmask;
> + agdev->params.c_srate = uac2_opts->c_srate;
> + agdev->params.c_ssize = uac2_opts->c_ssize;
> + agdev->params.req_number = uac2_opts->req_number;
> + ret = g_audio_setup(agdev, "UAC2 PCM", "UAC2_Gadget");
> if (ret)
> - goto err_no_memory;
> + goto err_free_descs;
> return 0;
>
> -err_no_memory:
> - kfree(agdev->uac2.p_prm.ureq);
> - kfree(agdev->uac2.c_prm.ureq);
> - kfree(agdev->uac2.p_prm.rbuf);
> - kfree(agdev->uac2.c_prm.rbuf);
> err_free_descs:
> usb_free_all_descriptors(fn);
> agdev->gadget = NULL;
> @@ -1094,15 +606,10 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> afunc_set_alt(struct usb_function *fn, unsigned intf, unsigned alt)
> {
> struct usb_composite_dev *cdev = fn->config->cdev;
> - struct audio_dev *agdev = func_to_agdev(fn);
> - struct f_uac2_opts *opts = agdev_to_uac2_opts(agdev);
> - struct snd_uac2_chip *uac2 = &agdev->uac2;
> + struct f_uac2 *uac2 = func_to_uac2(fn);
> struct usb_gadget *gadget = cdev->gadget;
> struct device *dev = &gadget->dev;
> - struct usb_request *req;
> - struct usb_ep *ep;
> - struct uac2_rtd_params *prm;
> - int req_len, i;
> + int ret = 0;
>
> /* No i/f has more than 2 alt settings */
> if (alt > 1) {
> @@ -1110,7 +617,7 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> return -EINVAL;
> }
>
> - if (intf == agdev->ac_intf) {
> + if (intf == uac2->ac_intf) {
> /* Control I/f has only 1 AltSetting - 0 */
> if (alt) {
> dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
> @@ -1119,92 +626,40 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> return 0;
> }
>
> - if (intf == agdev->as_out_intf) {
> - ep = agdev->out_ep;
> - prm = &uac2->c_prm;
> - config_ep_by_speed(gadget, fn, ep);
> - agdev->as_out_alt = alt;
> - req_len = prm->max_psize;
> - } else if (intf == agdev->as_in_intf) {
> - unsigned int factor, rate;
> - struct usb_endpoint_descriptor *ep_desc;
> -
> - ep = agdev->in_ep;
> - prm = &uac2->p_prm;
> - config_ep_by_speed(gadget, fn, ep);
> - agdev->as_in_alt = alt;
> -
> - /* pre-calculate the playback endpoint's interval */
> - if (gadget->speed == USB_SPEED_FULL) {
> - ep_desc = &fs_epin_desc;
> - factor = 1000;
> - } else {
> - ep_desc = &hs_epin_desc;
> - factor = 8000;
> - }
> -
> - /* pre-compute some values for iso_complete() */
> - uac2->p_framesize = opts->p_ssize *
> - num_channels(opts->p_chmask);
> - rate = opts->p_srate * uac2->p_framesize;
> - uac2->p_interval = factor / (1 << (ep_desc->bInterval - 1));
> - uac2->p_pktsize = min_t(unsigned int, rate / uac2->p_interval,
> - prm->max_psize);
> + if (intf == uac2->as_out_intf) {
> + uac2->as_out_alt = alt;
>
> - if (uac2->p_pktsize < prm->max_psize)
> - uac2->p_pktsize_residue = rate % uac2->p_interval;
> + if (alt)
> + ret = u_audio_start_capture(&uac2->g_audio);
> else
> - uac2->p_pktsize_residue = 0;
> + u_audio_stop_capture(&uac2->g_audio);
> + } else if (intf == uac2->as_in_intf) {
> + uac2->as_in_alt = alt;
>
> - req_len = uac2->p_pktsize;
> - uac2->p_residue = 0;
> + if (alt)
> + ret = u_audio_start_playback(&uac2->g_audio);
> + else
> + u_audio_stop_playback(&uac2->g_audio);
> } else {
> dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
> return -EINVAL;
> }
>
> - if (alt == 0) {
> - free_ep(prm, ep);
> - return 0;
> - }
> -
> - prm->ep_enabled = true;
> - usb_ep_enable(ep);
> -
> - for (i = 0; i < opts->req_number; i++) {
> - if (!prm->ureq[i].req) {
> - req = usb_ep_alloc_request(ep, GFP_ATOMIC);
> - if (req == NULL)
> - return -ENOMEM;
> -
> - prm->ureq[i].req = req;
> - prm->ureq[i].pp = prm;
> -
> - req->zero = 0;
> - req->context = &prm->ureq[i];
> - req->length = req_len;
> - req->complete = agdev_iso_complete;
> - req->buf = prm->rbuf + i * prm->max_psize;
> - }
> -
> - if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
> - dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
> - }
> -
> - return 0;
> + return ret;
> }
>
> static int
> afunc_get_alt(struct usb_function *fn, unsigned intf)
> {
> - struct audio_dev *agdev = func_to_agdev(fn);
> -
> - if (intf == agdev->ac_intf)
> - return agdev->ac_alt;
> - else if (intf == agdev->as_out_intf)
> - return agdev->as_out_alt;
> - else if (intf == agdev->as_in_intf)
> - return agdev->as_in_alt;
> + struct f_uac2 *uac2 = func_to_uac2(fn);
> + struct g_audio *agdev = func_to_g_audio(fn);
> +
> + if (intf == uac2->ac_intf)
> + return uac2->ac_alt;
> + else if (intf == uac2->as_out_intf)
> + return uac2->as_out_alt;
> + else if (intf == uac2->as_in_intf)
> + return uac2->as_in_alt;
> else
> dev_err(&agdev->gadget->dev,
> "%s:%d Invalid Interface %d!\n",
> @@ -1216,21 +671,19 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> static void
> afunc_disable(struct usb_function *fn)
> {
> - struct audio_dev *agdev = func_to_agdev(fn);
> - struct snd_uac2_chip *uac2 = &agdev->uac2;
> -
> - free_ep(&uac2->p_prm, agdev->in_ep);
> - agdev->as_in_alt = 0;
> + struct f_uac2 *uac2 = func_to_uac2(fn);
>
> - free_ep(&uac2->c_prm, agdev->out_ep);
> - agdev->as_out_alt = 0;
> + uac2->as_in_alt = 0;
> + uac2->as_out_alt = 0;
> + u_audio_stop_capture(&uac2->g_audio);
> + u_audio_stop_playback(&uac2->g_audio);
> }
>
> static int
> in_rq_cur(struct usb_function *fn, const struct usb_ctrlrequest *cr)
> {
> struct usb_request *req = fn->config->cdev->req;
> - struct audio_dev *agdev = func_to_agdev(fn);
> + struct g_audio *agdev = func_to_g_audio(fn);
> struct f_uac2_opts *opts;
> u16 w_length = le16_to_cpu(cr->wLength);
> u16 w_index = le16_to_cpu(cr->wIndex);
> @@ -1240,7 +693,7 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> int value = -EOPNOTSUPP;
> int p_srate, c_srate;
>
> - opts = agdev_to_uac2_opts(agdev);
> + opts = g_audio_to_uac2_opts(agdev);
> p_srate = opts->p_srate;
> c_srate = opts->c_srate;
>
> @@ -1271,7 +724,7 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> in_rq_range(struct usb_function *fn, const struct usb_ctrlrequest *cr)
> {
> struct usb_request *req = fn->config->cdev->req;
> - struct audio_dev *agdev = func_to_agdev(fn);
> + struct g_audio *agdev = func_to_g_audio(fn);
> struct f_uac2_opts *opts;
> u16 w_length = le16_to_cpu(cr->wLength);
> u16 w_index = le16_to_cpu(cr->wIndex);
> @@ -1282,7 +735,7 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> int value = -EOPNOTSUPP;
> int p_srate, c_srate;
>
> - opts = agdev_to_uac2_opts(agdev);
> + opts = g_audio_to_uac2_opts(agdev);
> p_srate = opts->p_srate;
> c_srate = opts->c_srate;
>
> @@ -1336,11 +789,12 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> static int
> setup_rq_inf(struct usb_function *fn, const struct usb_ctrlrequest *cr)
> {
> - struct audio_dev *agdev = func_to_agdev(fn);
> + struct f_uac2 *uac2 = func_to_uac2(fn);
> + struct g_audio *agdev = func_to_g_audio(fn);
> u16 w_index = le16_to_cpu(cr->wIndex);
> u8 intf = w_index & 0xff;
>
> - if (intf != agdev->ac_intf) {
> + if (intf != uac2->ac_intf) {
> dev_err(&agdev->gadget->dev,
> "%s:%d Error!\n", __func__, __LINE__);
> return -EOPNOTSUPP;
> @@ -1358,7 +812,7 @@ static void set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
> afunc_setup(struct usb_function *fn, const struct usb_ctrlrequest *cr)
> {
> struct usb_composite_dev *cdev = fn->config->cdev;
> - struct audio_dev *agdev = func_to_agdev(fn);
> + struct g_audio *agdev = func_to_g_audio(fn);
> struct usb_request *req = cdev->req;
> u16 w_length = le16_to_cpu(cr->wLength);
> int value = -EOPNOTSUPP;
> @@ -1504,10 +958,10 @@ static struct usb_function_instance *afunc_alloc_inst(void)
>
> static void afunc_free(struct usb_function *f)
> {
> - struct audio_dev *agdev;
> + struct g_audio *agdev;
> struct f_uac2_opts *opts;
>
> - agdev = func_to_agdev(f);
> + agdev = func_to_g_audio(f);
> opts = container_of(f->fi, struct f_uac2_opts, func_inst);
> kfree(agdev);
> mutex_lock(&opts->lock);
> @@ -1517,17 +971,9 @@ static void afunc_free(struct usb_function *f)
>
> static void afunc_unbind(struct usb_configuration *c, struct usb_function *f)
> {
> - struct audio_dev *agdev = func_to_agdev(f);
> - struct uac2_rtd_params *prm;
> -
> - snd_uac2_remove(agdev);
> -
> - prm = &agdev->uac2.p_prm;
> - kfree(prm->rbuf);
> + struct g_audio *agdev = func_to_g_audio(f);
>
> - prm = &agdev->uac2.c_prm;
> - kfree(prm->rbuf);
> - kfree(prm->ureq);
> + g_audio_cleanup(agdev);
> usb_free_all_descriptors(f);
>
> agdev->gadget = NULL;
> @@ -1535,11 +981,11 @@ static void afunc_unbind(struct usb_configuration *c, struct usb_function *f)
>
> static struct usb_function *afunc_alloc(struct usb_function_instance *fi)
> {
> - struct audio_dev *agdev;
> + struct f_uac2 *uac2;
> struct f_uac2_opts *opts;
>
> - agdev = kzalloc(sizeof(*agdev), GFP_KERNEL);
> - if (agdev == NULL)
> + uac2 = kzalloc(sizeof(*uac2), GFP_KERNEL);
> + if (uac2 == NULL)
> return ERR_PTR(-ENOMEM);
>
> opts = container_of(fi, struct f_uac2_opts, func_inst);
> @@ -1547,19 +993,20 @@ static struct usb_function *afunc_alloc(struct usb_function_instance *fi)
> ++opts->refcnt;
> mutex_unlock(&opts->lock);
>
> - agdev->func.name = "uac2_func";
> - agdev->func.bind = afunc_bind;
> - agdev->func.unbind = afunc_unbind;
> - agdev->func.set_alt = afunc_set_alt;
> - agdev->func.get_alt = afunc_get_alt;
> - agdev->func.disable = afunc_disable;
> - agdev->func.setup = afunc_setup;
> - agdev->func.free_func = afunc_free;
> + uac2->g_audio.func.name = "uac2_func";
> + uac2->g_audio.func.bind = afunc_bind;
> + uac2->g_audio.func.unbind = afunc_unbind;
> + uac2->g_audio.func.set_alt = afunc_set_alt;
> + uac2->g_audio.func.get_alt = afunc_get_alt;
> + uac2->g_audio.func.disable = afunc_disable;
> + uac2->g_audio.func.setup = afunc_setup;
> + uac2->g_audio.func.free_func = afunc_free;
>
> - return &agdev->func;
> + return &uac2->g_audio.func;
> }
>
> DECLARE_USB_FUNCTION_INIT(uac2, afunc_alloc_inst, afunc_alloc);
> MODULE_LICENSE("GPL");
> MODULE_AUTHOR("Yadwinder Singh");
> MODULE_AUTHOR("Jaswinder Singh");
> +MODULE_AUTHOR("Ruslan Bilovol");
>
drivers/usb/gadget/function/f_uac2.c | 721 ++++------------------------------
Basically you move out ALSA sound card implementation and %s/agdev/uac2/
I am not sure churn warrants a MODULE_AUTHOR. People have made far
more important contribution to the UAC2,
> diff --git a/drivers/usb/gadget/function/u_audio.c b/drivers/usb/gadget/function/u_audio.c
> new file mode 100644
> index 0000000..8ee65b8
> --- /dev/null
> +++ b/drivers/usb/gadget/function/u_audio.c
> @@ -0,0 +1,661 @@
> +/*
> + * u_audio.c -- interface to USB gadget "ALSA sound card" utilities
> + *
> + * Copyright (C) 2016
> + * Author: Ruslan Bilovol <ruslan.bilovol@xxxxxxxxx>
> + *
> + * Based on f_uac2.c which is:
> + * Copyright (C) 2011
> + * Yadwinder Singh (yadi.brar01@xxxxxxxxx)
> + * Jaswinder Singh (jaswinder.singh@xxxxxxxxxx)
> + *
Again this is not "based on", rather where you paste the code you cut
from f_uac2.c
Of course you also pad it with minor changes to make it useful to your
uac1 code. I am not happy with losing copyright on the sound card
implementation for the UAC drivers.
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/module.h>
> +#include <sound/core.h>
> +#include <sound/pcm.h>
> +#include <sound/pcm_params.h>
> +
> +#include "u_audio.h"
> +
> +#define BUFF_SIZE_MAX (PAGE_SIZE * 16)
> +#define PRD_SIZE_MAX PAGE_SIZE
> +#define MIN_PERIODS 4
> +
> +struct uac_req {
> + struct uac_rtd_params *pp; /* parent param */
> + struct usb_request *req;
> +};
> +
> +/* Runtime data params for one stream */
> +struct uac_rtd_params {
> + struct snd_uac_chip *uac; /* parent chip */
> + bool ep_enabled; /* if the ep is enabled */
> + /* Size of the ring buffer */
> + size_t dma_bytes;
> + unsigned char *dma_area;
> +
> + struct snd_pcm_substream *ss;
> +
> + /* Ring buffer */
> + ssize_t hw_ptr;
> +
> + void *rbuf;
> +
> + size_t period_size;
> +
> + unsigned max_psize; /* MaxPacketSize of endpoint */
> + struct uac_req *ureq;
> +
> + spinlock_t lock;
> +};
> +
> +struct snd_uac_chip {
> + struct g_audio *audio_dev;
> +
> + struct uac_rtd_params p_prm;
> + struct uac_rtd_params c_prm;
> +
> + struct snd_card *card;
> + struct snd_pcm *pcm;
> +
> + /* timekeeping for the playback endpoint */
> + unsigned int p_interval;
> + unsigned int p_residue;
> +
> + /* pre-calculated values for playback iso completion */
> + unsigned int p_pktsize;
> + unsigned int p_pktsize_residue;
> + unsigned int p_framesize;
> +};
> +
> +static struct snd_pcm_hardware uac_pcm_hardware = {
> + .info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER
> + | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID
> + | SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,
> + .rates = SNDRV_PCM_RATE_CONTINUOUS,
> + .periods_max = BUFF_SIZE_MAX / PRD_SIZE_MAX,
> + .buffer_bytes_max = BUFF_SIZE_MAX,
> + .period_bytes_max = PRD_SIZE_MAX,
> + .periods_min = MIN_PERIODS,
> +};
> +
> +static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req)
> +{
> + unsigned pending;
> + unsigned long flags;
> + unsigned int hw_ptr;
> + bool update_alsa = false;
> + int status = req->status;
> + struct uac_req *ur = req->context;
> + struct snd_pcm_substream *substream;
> + struct uac_rtd_params *prm = ur->pp;
> + struct snd_uac_chip *uac = prm->uac;
> +
> + /* i/f shutting down */
> + if (!prm->ep_enabled || req->status == -ESHUTDOWN)
> + return;
> +
> + /*
> + * We can't really do much about bad xfers.
> + * Afterall, the ISOCH xfers could fail legitimately.
> + */
> + if (status)
> + pr_debug("%s: iso_complete status(%d) %d/%d\n",
> + __func__, status, req->actual, req->length);
> +
> + substream = prm->ss;
> +
> + /* Do nothing if ALSA isn't active */
> + if (!substream)
> + goto exit;
> +
> + spin_lock_irqsave(&prm->lock, flags);
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> + /*
> + * For each IN packet, take the quotient of the current data
> + * rate and the endpoint's interval as the base packet size.
> + * If there is a residue from this division, add it to the
> + * residue accumulator.
> + */
> + req->length = uac->p_pktsize;
> + uac->p_residue += uac->p_pktsize_residue;
> +
> + /*
> + * Whenever there are more bytes in the accumulator than we
> + * need to add one more sample frame, increase this packet's
> + * size and decrease the accumulator.
> + */
> + if (uac->p_residue / uac->p_interval >= uac->p_framesize) {
> + req->length += uac->p_framesize;
> + uac->p_residue -= uac->p_framesize *
> + uac->p_interval;
> + }
> +
> + req->actual = req->length;
> + }
> +
> + pending = prm->hw_ptr % prm->period_size;
> + pending += req->actual;
> + if (pending >= prm->period_size)
> + update_alsa = true;
> +
> + hw_ptr = prm->hw_ptr;
> + prm->hw_ptr = (prm->hw_ptr + req->actual) % prm->dma_bytes;
> +
> + spin_unlock_irqrestore(&prm->lock, flags);
> +
> + /* Pack USB load in ALSA ring buffer */
> + pending = prm->dma_bytes - hw_ptr;
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> + if (unlikely(pending < req->actual)) {
> + memcpy(req->buf, prm->dma_area + hw_ptr, pending);
> + memcpy(req->buf + pending, prm->dma_area,
> + req->actual - pending);
> + } else {
> + memcpy(req->buf, prm->dma_area + hw_ptr, req->actual);
> + }
> + } else {
> + if (unlikely(pending < req->actual)) {
> + memcpy(prm->dma_area + hw_ptr, req->buf, pending);
> + memcpy(prm->dma_area, req->buf + pending,
> + req->actual - pending);
> + } else {
> + memcpy(prm->dma_area + hw_ptr, req->buf, req->actual);
> + }
> + }
> +
> +exit:
> + if (usb_ep_queue(ep, req, GFP_ATOMIC))
> + dev_err(uac->card->dev, "%d Error!\n", __LINE__);
> +
> + if (update_alsa)
> + snd_pcm_period_elapsed(substream);
> +}
> +
> +static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
> +{
> + struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
> + struct uac_rtd_params *prm;
> + struct g_audio *audio_dev;
> + struct uac_params *params;
> + unsigned long flags;
> + int err = 0;
> +
> + audio_dev = uac->audio_dev;
> + params = &audio_dev->params;
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + prm = &uac->p_prm;
> + else
> + prm = &uac->c_prm;
> +
> + spin_lock_irqsave(&prm->lock, flags);
> +
> + /* Reset */
> + prm->hw_ptr = 0;
> +
> + switch (cmd) {
> + case SNDRV_PCM_TRIGGER_START:
> + case SNDRV_PCM_TRIGGER_RESUME:
> + prm->ss = substream;
> + break;
> + case SNDRV_PCM_TRIGGER_STOP:
> + case SNDRV_PCM_TRIGGER_SUSPEND:
> + prm->ss = NULL;
> + break;
> + default:
> + err = -EINVAL;
> + }
> +
> + spin_unlock_irqrestore(&prm->lock, flags);
> +
> + /* Clear buffer after Play stops */
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !prm->ss)
> + memset(prm->rbuf, 0, prm->max_psize * params->req_number);
> +
> + return err;
> +}
> +
> +static snd_pcm_uframes_t uac_pcm_pointer(struct snd_pcm_substream *substream)
> +{
> + struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
> + struct uac_rtd_params *prm;
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + prm = &uac->p_prm;
> + else
> + prm = &uac->c_prm;
> +
> + return bytes_to_frames(substream->runtime, prm->hw_ptr);
> +}
> +
> +static int uac_pcm_hw_params(struct snd_pcm_substream *substream,
> + struct snd_pcm_hw_params *hw_params)
> +{
> + struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
> + struct uac_rtd_params *prm;
> + int err;
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + prm = &uac->p_prm;
> + else
> + prm = &uac->c_prm;
> +
> + err = snd_pcm_lib_malloc_pages(substream,
> + params_buffer_bytes(hw_params));
> + if (err >= 0) {
> + prm->dma_bytes = substream->runtime->dma_bytes;
> + prm->dma_area = substream->runtime->dma_area;
> + prm->period_size = params_period_bytes(hw_params);
> + }
> +
> + return err;
> +}
> +
> +static int uac_pcm_hw_free(struct snd_pcm_substream *substream)
> +{
> + struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
> + struct uac_rtd_params *prm;
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + prm = &uac->p_prm;
> + else
> + prm = &uac->c_prm;
> +
> + prm->dma_area = NULL;
> + prm->dma_bytes = 0;
> + prm->period_size = 0;
> +
> + return snd_pcm_lib_free_pages(substream);
> +}
> +
> +static int uac_pcm_open(struct snd_pcm_substream *substream)
> +{
> + struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
> + struct snd_pcm_runtime *runtime = substream->runtime;
> + struct g_audio *audio_dev;
> + struct uac_params *params;
> + int p_ssize, c_ssize;
> + int p_srate, c_srate;
> + int p_chmask, c_chmask;
> +
> + audio_dev = uac->audio_dev;
> + params = &audio_dev->params;
> + p_ssize = params->p_ssize;
> + c_ssize = params->c_ssize;
> + p_srate = params->p_srate;
> + c_srate = params->c_srate;
> + p_chmask = params->p_chmask;
> + c_chmask = params->c_chmask;
> + uac->p_residue = 0;
> +
> + runtime->hw = uac_pcm_hardware;
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> + spin_lock_init(&uac->p_prm.lock);
> + runtime->hw.rate_min = p_srate;
> + switch (p_ssize) {
> + case 3:
> + runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
> + break;
> + case 4:
> + runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
> + break;
> + default:
> + runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
> + break;
> + }
> + runtime->hw.channels_min = num_channels(p_chmask);
> + runtime->hw.period_bytes_min = 2 * uac->p_prm.max_psize
> + / runtime->hw.periods_min;
> + } else {
> + spin_lock_init(&uac->c_prm.lock);
> + runtime->hw.rate_min = c_srate;
> + switch (c_ssize) {
> + case 3:
> + runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
> + break;
> + case 4:
> + runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
> + break;
> + default:
> + runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
> + break;
> + }
> + runtime->hw.channels_min = num_channels(c_chmask);
> + runtime->hw.period_bytes_min = 2 * uac->c_prm.max_psize
> + / runtime->hw.periods_min;
> + }
> +
> + runtime->hw.rate_max = runtime->hw.rate_min;
> + runtime->hw.channels_max = runtime->hw.channels_min;
> +
> + snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
> +
> + return 0;
> +}
> +
> +/* ALSA cries without these function pointers */
> +static int uac_pcm_null(struct snd_pcm_substream *substream)
> +{
> + return 0;
> +}
> +
> +static struct snd_pcm_ops uac_pcm_ops = {
> + .open = uac_pcm_open,
> + .close = uac_pcm_null,
> + .ioctl = snd_pcm_lib_ioctl,
> + .hw_params = uac_pcm_hw_params,
> + .hw_free = uac_pcm_hw_free,
> + .trigger = uac_pcm_trigger,
> + .pointer = uac_pcm_pointer,
> + .prepare = uac_pcm_null,
> +};
> +
> +static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)
> +{
> + struct snd_uac_chip *uac = prm->uac;
> + struct g_audio *audio_dev;
> + struct uac_params *params;
> + int i;
> +
> + if (!prm->ep_enabled)
> + return;
> +
> + prm->ep_enabled = false;
> +
> + audio_dev = uac->audio_dev;
> + params = &audio_dev->params;
> +
> + for (i = 0; i < params->req_number; i++) {
> + if (prm->ureq[i].req) {
> + usb_ep_dequeue(ep, prm->ureq[i].req);
> + usb_ep_free_request(ep, prm->ureq[i].req);
> + prm->ureq[i].req = NULL;
> + }
> + }
> +
> + if (usb_ep_disable(ep))
> + dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
> +}
> +
> +
> +int u_audio_start_capture(struct g_audio *audio_dev)
> +{
> + struct snd_uac_chip *uac = audio_dev->uac;
> + struct usb_gadget *gadget = audio_dev->gadget;
> + struct device *dev = &gadget->dev;
> + struct usb_request *req;
> + struct usb_ep *ep;
> + struct uac_rtd_params *prm;
> + struct uac_params *params = &audio_dev->params;
> + int req_len, i;
> +
> + ep = audio_dev->out_ep;
> + prm = &uac->c_prm;
> + config_ep_by_speed(gadget, &audio_dev->func, ep);
> + req_len = prm->max_psize;
> +
> + prm->ep_enabled = true;
> + usb_ep_enable(ep);
> +
> + for (i = 0; i < params->req_number; i++) {
> + if (!prm->ureq[i].req) {
> + req = usb_ep_alloc_request(ep, GFP_ATOMIC);
> + if (req == NULL)
> + return -ENOMEM;
> +
> + prm->ureq[i].req = req;
> + prm->ureq[i].pp = prm;
> +
> + req->zero = 0;
> + req->context = &prm->ureq[i];
> + req->length = req_len;
> + req->complete = u_audio_iso_complete;
> + req->buf = prm->rbuf + i * prm->max_psize;
> + }
> +
> + if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
> + dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(u_audio_start_capture);
> +
> +void u_audio_stop_capture(struct g_audio *audio_dev)
> +{
> + struct snd_uac_chip *uac = audio_dev->uac;
> +
> + free_ep(&uac->c_prm, audio_dev->out_ep);
> +}
> +EXPORT_SYMBOL_GPL(u_audio_stop_capture);
> +
> +int u_audio_start_playback(struct g_audio *audio_dev)
> +{
> + struct snd_uac_chip *uac = audio_dev->uac;
> + struct usb_gadget *gadget = audio_dev->gadget;
> + struct device *dev = &gadget->dev;
> + struct usb_request *req;
> + struct usb_ep *ep;
> + struct uac_rtd_params *prm;
> + struct uac_params *params = &audio_dev->params;
> + unsigned int factor, rate;
> + const struct usb_endpoint_descriptor *ep_desc;
> + int req_len, i;
> +
> + ep = audio_dev->in_ep;
> + prm = &uac->p_prm;
> + config_ep_by_speed(gadget, &audio_dev->func, ep);
> +
> + ep_desc = ep->desc;
> +
> + /* pre-calculate the playback endpoint's interval */
> + if (gadget->speed == USB_SPEED_FULL)
> + factor = 1000;
> + else
> + factor = 8000;
> +
> + /* pre-compute some values for iso_complete() */
> + uac->p_framesize = params->p_ssize *
> + num_channels(params->p_chmask);
> + rate = params->p_srate * uac->p_framesize;
> + uac->p_interval = factor / (1 << (ep_desc->bInterval - 1));
> + uac->p_pktsize = min_t(unsigned int, rate / uac->p_interval,
> + prm->max_psize);
> +
> + if (uac->p_pktsize < prm->max_psize)
> + uac->p_pktsize_residue = rate % uac->p_interval;
> + else
> + uac->p_pktsize_residue = 0;
> +
> + req_len = uac->p_pktsize;
> + uac->p_residue = 0;
> +
> + prm->ep_enabled = true;
> + usb_ep_enable(ep);
> +
> + for (i = 0; i < params->req_number; i++) {
> + if (!prm->ureq[i].req) {
> + req = usb_ep_alloc_request(ep, GFP_ATOMIC);
> + if (req == NULL)
> + return -ENOMEM;
> +
> + prm->ureq[i].req = req;
> + prm->ureq[i].pp = prm;
> +
> + req->zero = 0;
> + req->context = &prm->ureq[i];
> + req->length = req_len;
> + req->complete = u_audio_iso_complete;
> + req->buf = prm->rbuf + i * prm->max_psize;
> + }
> +
> + if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
> + dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(u_audio_start_playback);
> +
> +void u_audio_stop_playback(struct g_audio *audio_dev)
> +{
> + struct snd_uac_chip *uac = audio_dev->uac;
> +
> + free_ep(&uac->p_prm, audio_dev->in_ep);
> +}
> +EXPORT_SYMBOL_GPL(u_audio_stop_playback);
> +
> +int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
> + const char *card_name)
> +{
> + struct snd_uac_chip *uac;
> + struct snd_card *card;
> + struct snd_pcm *pcm;
> + struct uac_params *params;
> + int p_chmask, c_chmask;
> + int err;
> +
> + if (!g_audio)
> + return -EINVAL;
> +
> + uac = kzalloc(sizeof(*uac), GFP_KERNEL);
> + if (!uac)
> + return -ENOMEM;
> + g_audio->uac = uac;
> + uac->audio_dev = g_audio;
> +
> + params = &g_audio->params;
> + p_chmask = params->p_chmask;
> + c_chmask = params->c_chmask;
> +
> + if (c_chmask) {
> + struct uac_rtd_params *prm = &uac->c_prm;
> +
> + uac->c_prm.uac = uac;
> + prm->max_psize = g_audio->out_ep_maxpsize;
> +
> + prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
> + GFP_KERNEL);
> + if (!prm->ureq) {
> + err = -ENOMEM;
> + goto fail;
> + }
> +
> + prm->rbuf = kcalloc(params->req_number, prm->max_psize,
> + GFP_KERNEL);
> + if (!prm->rbuf) {
> + prm->max_psize = 0;
> + err = -ENOMEM;
> + goto fail;
> + }
> + }
> +
> + if (p_chmask) {
> + struct uac_rtd_params *prm = &uac->p_prm;
> +
> + uac->p_prm.uac = uac;
> + prm->max_psize = g_audio->in_ep_maxpsize;
> +
> + prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
> + GFP_KERNEL);
> + if (!prm->ureq) {
> + err = -ENOMEM;
> + goto fail;
> + }
> +
> + prm->rbuf = kcalloc(params->req_number, prm->max_psize,
> + GFP_KERNEL);
> + if (!prm->rbuf) {
> + prm->max_psize = 0;
> + err = -ENOMEM;
> + goto fail;
> + }
> + }
> +
> + /* Choose any slot, with no id */
> + err = snd_card_new(&g_audio->gadget->dev,
> + -1, NULL, THIS_MODULE, 0, &card);
> + if (err < 0)
> + goto fail;
> +
> + uac->card = card;
> +
> + /*
> + * Create first PCM device
> + * Create a substream only for non-zero channel streams
> + */
> + err = snd_pcm_new(uac->card, pcm_name, 0,
> + p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
> + if (err < 0)
> + goto snd_fail;
> +
> + strcpy(pcm->name, pcm_name);
> + pcm->private_data = uac;
> + uac->pcm = pcm;
> +
> + snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops);
> + snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops);
> +
> + strcpy(card->driver, card_name);
> + strcpy(card->shortname, card_name);
> + sprintf(card->longname, "%s %i", card_name, card->dev->id);
> +
> + snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
> + snd_dma_continuous_data(GFP_KERNEL), 0, BUFF_SIZE_MAX);
> +
> + err = snd_card_register(card);
> +
> + if (!err)
> + return 0;
> +
> +snd_fail:
> + snd_card_free(card);
> +fail:
> + kfree(uac->p_prm.ureq);
> + kfree(uac->c_prm.ureq);
> + kfree(uac->p_prm.rbuf);
> + kfree(uac->c_prm.rbuf);
> + kfree(uac);
> +
> + return err;
> +}
> +EXPORT_SYMBOL_GPL(g_audio_setup);
> +
> +void g_audio_cleanup(struct g_audio *g_audio)
> +{
> + struct snd_uac_chip *uac;
> + struct snd_card *card;
> +
> + if (!g_audio || !g_audio->uac)
> + return;
> +
> + uac = g_audio->uac;
> + card = uac->card;
> + if (card)
> + snd_card_free(card);
> +
> + kfree(uac->p_prm.ureq);
> + kfree(uac->c_prm.ureq);
> + kfree(uac->p_prm.rbuf);
> + kfree(uac->c_prm.rbuf);
> + kfree(uac);
> +}
> +EXPORT_SYMBOL_GPL(g_audio_cleanup);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities");
> +MODULE_AUTHOR("Ruslan Bilovol");
> diff --git a/drivers/usb/gadget/function/u_audio.h b/drivers/usb/gadget/function/u_audio.h
> new file mode 100644
> index 0000000..07e1378
> --- /dev/null
> +++ b/drivers/usb/gadget/function/u_audio.h
> @@ -0,0 +1,95 @@
> +/*
> + * u_audio.h -- interface to USB gadget "ALSA sound card" utilities
> + *
> + * Copyright (C) 2016
> + * Author: Ruslan Bilovol <ruslan.bilovol@xxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef __U_AUDIO_H
> +#define __U_AUDIO_H
> +
> +#include <linux/usb/composite.h>
> +
> +struct uac_params {
> + /* playback */
> + int p_chmask; /* channel mask */
> + int p_srate; /* rate in Hz */
> + int p_ssize; /* sample size */
> +
> + /* capture */
> + int c_chmask; /* channel mask */
> + int c_srate; /* rate in Hz */
> + int c_ssize; /* sample size */
> +
> + int req_number; /* number of preallocated requests */
> +};
> +
> +struct g_audio {
> + struct usb_function func;
> + struct usb_gadget *gadget;
> +
> + struct usb_ep *in_ep;
> + struct usb_ep *out_ep;
> +
> + /* Max packet size for all in_ep possible speeds */
> + unsigned int in_ep_maxpsize;
> + /* Max packet size for all out_ep possible speeds */
> + unsigned int out_ep_maxpsize;
> +
> + /* The ALSA Sound Card it represents on the USB-Client side */
> + struct snd_uac_chip *uac;
> +
> + struct uac_params params;
> +};
> +
> +static inline struct g_audio *func_to_g_audio(struct usb_function *f)
> +{
> + return container_of(f, struct g_audio, func);
> +}
> +
> +static inline uint num_channels(uint chanmask)
> +{
> + uint num = 0;
> +
> + while (chanmask) {
> + num += (chanmask & 1);
> + chanmask >>= 1;
> + }
> +
> + return num;
> +}
> +
> +/*
> + * g_audio_setup - initialize one virtual ALSA sound card
> + * @g_audio: struct with filled params, in_ep_maxpsize, out_ep_maxpsize
> + * @pcm_name: the id string for a PCM instance of this sound card
> + * @card_name: name of this soundcard
> + *
> + * This sets up the single virtual ALSA sound card that may be exported by a
> + * gadget driver using this framework.
> + *
> + * Context: may sleep
> + *
> + * Returns zero on success, or a negative error on failure.
> + */
> +int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
> + const char *card_name);
> +void g_audio_cleanup(struct g_audio *g_audio);
> +
> +int u_audio_start_capture(struct g_audio *g_audio);
> +void u_audio_stop_capture(struct g_audio *g_audio);
> +int u_audio_start_playback(struct g_audio *g_audio);
> +void u_audio_stop_playback(struct g_audio *g_audio);
> +
> +#endif /* __U_AUDIO_H */
> diff --git a/drivers/usb/gadget/legacy/Kconfig b/drivers/usb/gadget/legacy/Kconfig
> index 0b36878..5344064 100644
> --- a/drivers/usb/gadget/legacy/Kconfig
> +++ b/drivers/usb/gadget/legacy/Kconfig
> @@ -56,6 +56,7 @@ config USB_AUDIO
> select SND_PCM
> select USB_F_UAC1 if GADGET_UAC1
> select USB_F_UAC2 if !GADGET_UAC1
> + select USB_U_AUDIO if USB_F_UAC2
> help
> This Gadget Audio driver is compatible with USB Audio Class
> specification 2.0. It implements 1 AudioControl interface,
> --
> 1.9.1
>