V4L/DVB (6949): Adds em28xx-audio module

em28xx-audio module exports em28xx Vendor Class audio as an -alsa
driver. This module were written based on usbaudio driver by Markus
Rechberger. Recently, he acked to allow us to merge it on kernel:

http://lists-archives.org/video4linux/20408-supporting-prolink-pixelview-405-dvd-maker.html

Thanks to Markus Rechberger <mrechberger@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/em28xx/em28xx-audio.c

+/*
+ *  Empiatech em28x1 audio extension
+ *
+ *  Copyright (C) 2006 Markus Rechberger <mrechberger@gmail.com>
+ *
+ *  This driver is based on my previous au600 usb pstn audio driver
+ *  and inherits all the copyrights
+ *
+ *  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.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/usb.h>
+#include <linux/init.h>
+#include <linux/sound.h>
+#include <linux/spinlock.h>
+#include <linux/soundcard.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/proc_fs.h>
+#include <linux/moduleparam.h>
+#include <sound/driver.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/info.h>
+#include <sound/initval.h>
+#include <sound/control.h>
+//#include <linux/video_decoder.h>
+//#include <media/tuner.h>
+#include <media/v4l2-common.h>
+#include "em28xx.h"
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
+static int em28xx_cmd(struct em28xx *dev, int cmd,int arg);
+
+
+static int snd_pcm_alloc_vmalloc_buffer(struct snd_pcm_substream *subs, size_t size)
+{
+	struct snd_pcm_runtime *runtime = subs->runtime;
+	if(runtime->dma_area){
+		if(runtime->dma_bytes > size)
+			return 0;
+		vfree(runtime->dma_area);
+	}
+	runtime->dma_area = vmalloc(size);
+	if(!runtime ->dma_area)
+		return -ENOMEM;
+	runtime->dma_bytes = size;
+	return 0;
+}
+
+static struct snd_pcm_hardware snd_em28xx_hw_capture = {
+	.info = SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED  | SNDRV_PCM_INFO_MMAP_VALID,
+	.formats = SNDRV_PCM_FMTBIT_S16_LE,
+	.rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_KNOT,
+	.rate_min = 48000,
+	.rate_max = 48000,
+	.channels_min = 2,
+	.channels_max = 2,
+	.buffer_bytes_max = 62720*8, /* just about the value in usbaudio.c */
+	.period_bytes_min = 64, //12544/2,
+	.period_bytes_max = 12544,
+	.periods_min = 2,
+	.periods_max = 98, //12544,
+};
+
+static int snd_em28xx_capture_open(struct snd_pcm_substream *substream)
+{
+	int ret = 0;
+	int mode;
+	struct em28xx *dev = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	printk("opening radio device and trying to acquire exclusive lock\n");
+        switch(dev->mode){
+                case TUNER_STUB_DVBC_TV:
+                case TUNER_STUB_DVBT_TV:
+                case TUNER_STUB_ATSC_TV:
+			/* digital has no support for analog audio */
+			if (ret != 0 ) {
+				printk("device is already in use by DVB-T\n");
+				return -EINVAL;
+			} else {
+				struct v4l2_tuner tuner;
+				printk("switching device to FM mode\n");
+
+				mode = TUNER_STUB_RADIO;
+				memset(&tuner, 0x0, sizeof(struct v4l2_tuner));
+				tuner.type = V4L2_TUNER_RADIO;
+
+				/* enable GPIO for analog TV */
+				dev->em28xx_gpio_control(dev,  EM28XX_MODE, (void*)mode);
+				dev->mode = mode;
+				/* upload firmware */
+				tuner_run_cmd(dev->tobj, TUNER_CMD_INIT, (void*)mode);
+
+				/* required for devices which have kerneldriver dependencies */
+//				em28xx_config(dev);
+//				em28xx_config_i2c(dev);
+
+				/* this is moreover to switch the decoder to FM */
+				em28xx_i2c_call_clients(dev, VIDIOC_S_TUNER, &tuner);
+
+				dev->em28xx_write_regs(dev, 0x0f, "\x87", 1); 
+				ret = dev->em28xx_acquire(dev, EM28XX_RADIO, 1); 
+				em28xx_i2c_call_clients(dev, VIDIOC_INT_RESET, 0);
+				/* TODO switch to FM mode */
+
+				printk("em28xx-audio: %d mode\n", mode);
+				tuner_run_cmd(dev->tobj, TUNER_CMD_G_MODE, &mode);
+				printk("retrieved mode from tuner: %d\n",mode);
+			}
+			break;
+
+                case TUNER_STUB_ANALOG_TV:
+			printk("em28xx-audio: device is currently in analog TV mode\n");
+			/* unmute by default */
+			dev->em28xx_write_regs(dev, 0x0f, "\x87", 1); 
+			break;
+                case TUNER_STUB_RADIO:
+			/* check current mode and put a hard lock onto it */
+			printk("em28xx-audio: device is currently in analogue FM mode\n");
+			/* unmute by default here */
+			dev->em28xx_write_regs(dev, 0x0f, "\x87", 1); 
+			ret = dev->em28xx_acquire(dev, EM28XX_RADIO, 1); 
+			if ( ret == 0 ) 
+				printk("device is locked in fmradio mode now\n");
+			break;
+		default:
+			printk("em28xx-audio: unhandled mode %d\n", dev->mode);
+	}
+
+	runtime->hw = snd_em28xx_hw_capture;
+	if(dev->alt == 0 && dev->adev->users == 0 ) {
+		int errCode;
+		dev->alt = 7;
+		errCode = usb_set_interface(dev->udev, 0, 7);
+		printk("changing alternate number to 7\n");
+	}
+	dev->adev->users++;
+	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
+	dev->adev->capture_pcm_substream = substream;
+	runtime->private_data = dev;
+	return 0;
+}
+
+static int snd_em28xx_pcm_close(struct snd_pcm_substream *substream)
+{
+	struct em28xx *dev = snd_pcm_substream_chip(substream);
+	int amode = 0;
+	dev->adev->users--;
+
+	/* decrease audio reference */
+	switch(dev->mode) {
+		case TUNER_STUB_ANALOG_TV:
+			amode = EM28XX_VIDEO;
+			break;
+		case TUNER_STUB_RADIO:
+			amode = EM28XX_RADIO;
+			break;
+		default:
+			printk("invalid mode: %d\n",dev->mode);
+			break;
+	}
+
+	dev->em28xx_acquire(dev, amode, 0); 
+
+	if(dev->adev->users == 0 && dev->adev->shutdown == 1) {
+		printk("audio users: %d\n",dev->adev->users);
+		printk("disabling audio stream!\n");
+		dev->adev->shutdown = 0;
+		printk("released lock\n");
+		em28xx_cmd(dev,EM28XX_CAPTURE_STREAM_EN,0);
+	}
+	return 0;
+}
+
+static int snd_em28xx_hw_capture_params(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *hw_params)
+{
+	unsigned int channels, rate, format;
+	int ret;
+	ret = snd_pcm_alloc_vmalloc_buffer(substream, params_buffer_bytes(hw_params));
+	format = params_format(hw_params);
+	rate = params_rate(hw_params);
+	channels = params_channels(hw_params);
+	/* TODO: set up em28xx audio chip to deliver the correct audio format, current default is 48000hz multiplexed => 96000hz mono
+	   which shouldn't matter since analogue TV only supports mono*/
+	return 0;
+}
+
+static int snd_em28xx_hw_capture_free(struct snd_pcm_substream *substream)
+{
+	struct em28xx *dev = snd_pcm_substream_chip(substream);
+	if(dev->adev->capture_stream==STREAM_ON){
+		em28xx_cmd(dev,EM28XX_CAPTURE_STREAM_EN,0);
+	}
+	return 0;
+}
+
+static int snd_em28xx_prepare(struct snd_pcm_substream *substream)
+{
+	return 0;
+}
+
+static int snd_em28xx_capture_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct em28xx *dev = snd_pcm_substream_chip(substream);
+	switch(cmd){
+		case SNDRV_PCM_TRIGGER_START:
+			em28xx_cmd(dev,EM28XX_CAPTURE_STREAM_EN,1);
+			return 0;
+		case SNDRV_PCM_TRIGGER_STOP:
+			dev->adev->shutdown=1;
+			return 0;
+		default:
+			return -EINVAL;
+	}
+}
+
+static void em28xx_audio_isocirq(struct urb *urb)
+{
+	struct em28xx *dev=urb->context;
+	int i;
+	unsigned int oldptr;
+	unsigned long flags;
+	int period_elapsed = 0;
+	int status;
+	unsigned char *cp;
+	unsigned int stride;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	if(dev->adev->capture_pcm_substream){
+		substream=dev->adev->capture_pcm_substream;
+		runtime=substream->runtime;
+
+		stride = runtime->frame_bits >> 3;
+		for(i=0;i<urb->number_of_packets;i++){
+			int length=urb->iso_frame_desc[i].actual_length/stride;
+			cp=(unsigned char *) urb->transfer_buffer + urb->iso_frame_desc[i].offset;
+
+			if(!length)
+				continue;
+
+			spin_lock_irqsave(&dev->adev->slock, flags);
+			oldptr = dev->adev->hwptr_done_capture;
+			dev->adev->hwptr_done_capture +=length;
+			if(dev->adev->hwptr_done_capture >= runtime->buffer_size)
+				dev->adev->hwptr_done_capture -= runtime->buffer_size;
+
+			dev->adev->capture_transfer_done += length;
+			if(dev->adev->capture_transfer_done >= runtime->period_size){
+				dev->adev->capture_transfer_done -= runtime->period_size;
+				period_elapsed=1;
+			}
+			spin_unlock_irqrestore(&dev->adev->slock, flags);
+
+			if(oldptr + length >= runtime->buffer_size){
+				unsigned int cnt = runtime->buffer_size-oldptr-1;
+				memcpy(runtime->dma_area+oldptr*stride, cp , cnt*stride);
+				memcpy(runtime->dma_area, cp + cnt, length*stride - cnt*stride);
+			} else {
+				memcpy(runtime->dma_area+oldptr*stride, cp, length*stride);
+			}
+		}
+		if(period_elapsed){
+			snd_pcm_period_elapsed(substream);
+		}
+	}
+	urb->status = 0;
+	
+	if(dev->adev->shutdown)
+		return;
+
+	if((status = usb_submit_urb(urb, GFP_ATOMIC))){
+		em28xx_errdev("resubmit of audio urb failed (error=%i)\n", status);
+	}
+	return;
+}
+
+static int em28xx_isoc_audio_deinit(struct em28xx *dev)
+{
+	int i;
+	for(i=0;i<EM28XX_AUDIO_BUFS;i++){
+		usb_kill_urb(dev->adev->urb[i]);
+		usb_free_urb(dev->adev->urb[i]);
+		dev->adev->urb[i]=NULL;
+	}
+	return 0;
+}
+
+static int em28xx_init_audio_isoc(struct em28xx *dev)
+{
+	int i;
+	int errCode;
+	const int sb_size=EM28XX_NUM_AUDIO_PACKETS * EM28XX_AUDIO_MAX_PACKET_SIZE;
+
+
+	for(i=0;i<EM28XX_AUDIO_BUFS;i++){
+		struct urb *urb;
+		int j,k;
+		dev->adev->transfer_buffer[i]=kmalloc(sb_size,GFP_ATOMIC);
+		if(!dev->adev->transfer_buffer[i]){
+			return -ENOMEM;
+		}
+		memset(dev->adev->transfer_buffer[i],0x80,sb_size);
+		urb = usb_alloc_urb(EM28XX_NUM_AUDIO_PACKETS,GFP_ATOMIC);
+		if(urb){
+			urb->dev=dev->udev;
+			urb->context=dev;
+			urb->pipe=usb_rcvisocpipe(dev->udev,0x83);
+			urb->transfer_flags = URB_ISO_ASAP;
+			urb->transfer_buffer = dev->adev->transfer_buffer[i];
+			urb->interval=1;
+			urb->complete = em28xx_audio_isocirq;
+			urb->number_of_packets = EM28XX_NUM_AUDIO_PACKETS;
+			urb->transfer_buffer_length = sb_size;
+			for(j=k=0; j<EM28XX_NUM_AUDIO_PACKETS;j++,k+=EM28XX_AUDIO_MAX_PACKET_SIZE){
+				urb->iso_frame_desc[j].offset = k;
+				urb->iso_frame_desc[j].length=EM28XX_AUDIO_MAX_PACKET_SIZE;
+			}
+			dev->adev->urb[i]=urb;
+		} else {
+			return -ENOMEM;
+		}
+	}
+	for(i=0;i<EM28XX_AUDIO_BUFS;i++){
+		errCode = usb_submit_urb(dev->adev->urb[i], GFP_ATOMIC);
+		if (errCode){
+			em28xx_isoc_audio_deinit(dev);
+			return errCode;
+		}
+	}
+	return 0;
+}
+
+
+static int em28xx_cmd(struct em28xx *dev, int cmd,int arg)
+{
+	switch(cmd){
+		case EM28XX_CAPTURE_STREAM_EN:
+			if(dev->adev->capture_stream == STREAM_OFF && arg==1){
+				dev->adev->capture_stream=STREAM_ON;
+				em28xx_init_audio_isoc(dev);
+			} else if (dev->adev->capture_stream==STREAM_ON && arg==0){
+				dev->adev->capture_stream=STREAM_OFF;
+				em28xx_isoc_audio_deinit(dev);
+			} else {
+				printk("An underrun occured very likely... ignoring it\n");
+			}
+			return 0;
+		default:
+			return -EINVAL;
+	}
+}
+
+static snd_pcm_uframes_t snd_em28xx_capture_pointer(struct snd_pcm_substream *substream)
+{
+	struct em28xx *dev;
+	snd_pcm_uframes_t hwptr_done;
+	dev = snd_pcm_substream_chip(substream);
+	hwptr_done = dev->adev->hwptr_done_capture;
+	return hwptr_done;
+}
+
+static struct page *snd_pcm_get_vmalloc_page(struct snd_pcm_substream *subs,
+					     unsigned long offset)
+{
+	void *pageptr = subs->runtime->dma_area + offset;
+	return vmalloc_to_page(pageptr);
+}
+
+static struct snd_pcm_ops snd_em28xx_pcm_capture = {
+	.open = snd_em28xx_capture_open,
+	.close = snd_em28xx_pcm_close,
+	.ioctl = snd_pcm_lib_ioctl,
+	.hw_params = snd_em28xx_hw_capture_params,
+	.hw_free = snd_em28xx_hw_capture_free,
+	.prepare = snd_em28xx_prepare,
+	.trigger = snd_em28xx_capture_trigger,
+	.pointer = snd_em28xx_capture_pointer,
+	.page = snd_pcm_get_vmalloc_page,
+};
+
+
+static int em28xx_audio_init(struct em28xx *dev)
+{
+	struct em28xx_audio *adev;
+	struct snd_pcm *pcm;
+	struct snd_card *card;
+	static int devnr;
+	int ret;
+	int err;
+	printk("em28xx-audio.c: probing for em28x1 non standard usbaudio\n");
+	printk("em28xx-audio.c: Copyright (C) 2006 Markus Rechberger\n");
+	adev=kzalloc(sizeof(*adev),GFP_KERNEL);
+	if(!adev){
+		printk("em28xx-audio.c: out of memory\n");
+		return -1;
+	}
+	card = snd_card_new(index[devnr], "Em28xx Audio", THIS_MODULE,0);
+	if(card==NULL){
+		kfree(adev);
+		return -ENOMEM;
+	}
+
+	spin_lock_init(&adev->slock);
+	ret=snd_pcm_new(card, "Em28xx Audio", 0, 0, 1, &pcm);
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_em28xx_pcm_capture);
+	pcm->info_flags = 0;
+	pcm->private_data = dev;
+	strcpy(pcm->name,"Empia 28xx Capture");
+	strcpy(card->driver, "Empia Em28xx Audio");
+	strcpy(card->shortname, "Em28xx Audio");
+	strcpy(card->longname,"Empia Em28xx Audio");
+
+	if((err = snd_card_register(card))<0){
+		snd_card_free(card);
+		return -ENOMEM;
+	}
+	adev->sndcard=card;
+	adev->udev=dev->udev;
+	dev->adev=adev;
+	return 0;
+}
+
+static int em28xx_audio_fini(struct em28xx *dev)
+{
+	if(dev==NULL)
+		return 0;
+	if(dev->adev){
+		snd_card_free(dev->adev->sndcard);
+		kfree(dev->adev);
+		dev->adev=NULL;
+	}
+	return 0;
+}
+
+static struct em28xx_ops audio_ops = {
+	.id	= EM28XX_AUDIO,
+	.name	= "Em28xx Audio Extension",
+	.init	= em28xx_audio_init,
+	.fini	= em28xx_audio_fini,
+};
+
+static int __init em28xx_alsa_register(void)
+{
+	request_module("em28xx");
+	request_module("tuner");
+	return em28xx_register_extension(&audio_ops);
+}
+
+static void __exit em28xx_alsa_unregister(void)
+{
+	em28xx_unregister_extension(&audio_ops);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Markus Rechberger <mrechberger@gmail.com>");
+MODULE_DESCRIPTION("Em28xx Audio driver");
+
+module_init(em28xx_alsa_register);
+module_exit(em28xx_alsa_unregister);