path: root/drivers/usb/gadget/f_uac2.c

/*
 * f_uac2.c -- USB Audio Class 2.0 Function
 *
 * Copyright (C) 2011
 *    Yadwinder Singh (yadi.brar01@gmail.com)
 *    Jaswinder Singh (jaswinder.singh@linaro.org)
 *
 * 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.
 */

#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>
#include <linux/platform_device.h>
#include <linux/module.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>

/* Playback(USB-IN) Default Stereo - Fl/Fr */
static int p_chmask = 0x3;
module_param(p_chmask, uint, S_IRUGO);
MODULE_PARM_DESC(p_chmask, "Playback Channel Mask");

/* Playback Default 48 KHz */
static int p_srate = 48000;
module_param(p_srate, uint, S_IRUGO);
MODULE_PARM_DESC(p_srate, "Playback Sampling Rate");

/* Playback Default 16bits/sample */
static int p_ssize = 2;
module_param(p_ssize, uint, S_IRUGO);
MODULE_PARM_DESC(p_ssize, "Playback Sample Size(bytes)");

/* Capture(USB-OUT) Default Stereo - Fl/Fr */
static int c_chmask = 0x3;
module_param(c_chmask, uint, S_IRUGO);
MODULE_PARM_DESC(c_chmask, "Capture Channel Mask");

/* Capture Default 64 KHz */
static int c_srate = 64000;
module_param(c_srate, uint, S_IRUGO);
MODULE_PARM_DESC(c_srate, "Capture Sampling Rate");

/* Capture Default 16bits/sample */
static int c_ssize = 2;
module_param(c_ssize, uint, S_IRUGO);
MODULE_PARM_DESC(c_ssize, "Capture Sample Size(bytes)");

#define DMA_ADDR_INVALID	(~(dma_addr_t)0)

#define ALT_SET(x, a)	do {(x) &= ~0xff; (x) |= (a); } while (0)
#define ALT_GET(x)	((x) & 0xff)
#define INTF_SET(x, i)	do {(x) &= 0xff; (x) |= ((i) << 8); } while (0)
#define INTF_GET(x)	((x >> 8) & 0xff)

/* Keep everyone on toes */
#define USB_XFERS	2

/*
 * The driver implements a simple UAC_2 topology.
 * USB-OUT -> IT_1 -> OT_3 -> ALSA_Capture
 * ALSA_Playback -> IT_2 -> OT_4 -> USB-IN
 * Capture and Playback sampling rates are independently
 *  controlled by two clock sources :
 *    CLK_5 := c_srate, and CLK_6 := p_srate
 */
#define USB_OUT_IT_ID	1
#define IO_IN_IT_ID	2
#define IO_OUT_OT_ID	3
#define USB_IN_OT_ID	4
#define USB_OUT_CLK_ID	5
#define USB_IN_CLK_ID	6

#define CONTROL_ABSENT	0
#define CONTROL_RDONLY	1
#define CONTROL_RDWR	3

#define CLK_FREQ_CTRL	0
#define CLK_VLD_CTRL	2

#define COPY_CTRL	0
#define CONN_CTRL	2
#define OVRLD_CTRL	4
#define CLSTR_CTRL	6
#define UNFLW_CTRL	8
#define OVFLW_CTRL	10

const char *uac2_name = "snd_uac2";

struct uac2_req {
	struct uac2_rtd_params *pp; /* parent param */
	struct usb_request *req;
};

struct uac2_rtd_params {
	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[USB_XFERS];

	spinlock_t lock;
};

struct snd_uac2_chip {
	struct platform_device pdev;
	struct platform_driver pdrv;

	struct uac2_rtd_params p_prm;
	struct uac2_rtd_params c_prm;

	struct snd_card *card;
	struct snd_pcm *pcm;
};

#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 {
	/* Currently active {Interface[15:8] | AltSettings[7:0]} */
	__u16 ac_alt, as_out_alt,