i810_audio.c

讲述linux的初始化过程

			return -EINVAL;
		spin_lock_irqsave(&state->card->lock, flags);
		i810_update_ptr(state);
		cinfo.bytes = dmabuf->total_bytes;
		cinfo.blocks = dmabuf->count >> dmabuf->fragshift;
		cinfo.ptr = dmabuf->hwptr;
		if (dmabuf->mapped)
			dmabuf->count &= dmabuf->fragsize-1;
		spin_unlock_irqrestore(&state->card->lock, flags);
		return copy_to_user((void *)arg, &cinfo, sizeof(cinfo));

	case SNDCTL_DSP_GETOPTR:
		if (!(file->f_mode & FMODE_WRITE))
			return -EINVAL;
		spin_lock_irqsave(&state->card->lock, flags);
		i810_update_ptr(state);
		cinfo.bytes = dmabuf->total_bytes;
		cinfo.blocks = dmabuf->count >> dmabuf->fragshift;
		cinfo.ptr = dmabuf->hwptr;
		if (dmabuf->mapped)
			dmabuf->count &= dmabuf->fragsize-1;
		spin_unlock_irqrestore(&state->card->lock, flags);
		return copy_to_user((void *)arg, &cinfo, sizeof(cinfo));

	case SNDCTL_DSP_SETDUPLEX:
		return -EINVAL;

	case SNDCTL_DSP_GETODELAY:
		if (!(file->f_mode & FMODE_WRITE))
			return -EINVAL;
		spin_lock_irqsave(&state->card->lock, flags);
		i810_update_ptr(state);
		val = dmabuf->count;
		spin_unlock_irqrestore(&state->card->lock, flags);
		return put_user(val, (int *)arg);

	case SOUND_PCM_READ_RATE:
		return put_user(dmabuf->rate, (int *)arg);

	case SOUND_PCM_READ_CHANNELS:
		return put_user((dmabuf->fmt & I810_FMT_STEREO) ? 2 : 1,
				(int *)arg);

	case SOUND_PCM_READ_BITS:
		return put_user(AFMT_S16_LE, (int *)arg);

	case SNDCTL_DSP_MAPINBUF:
	case SNDCTL_DSP_MAPOUTBUF:
	case SNDCTL_DSP_SETSYNCRO:
	case SOUND_PCM_WRITE_FILTER:
	case SOUND_PCM_READ_FILTER:
		return -EINVAL;
	}
	return -EINVAL;
}

static int i810_open(struct inode *inode, struct file *file)
{
	int i = 0;
	struct i810_card *card = devs;
	struct i810_state *state = NULL;
	struct dmabuf *dmabuf = NULL;

	/* find an avaiable virtual channel (instance of /dev/dsp) */
	while (card != NULL) {
		for (i = 0; i < NR_HW_CH; i++) {
			if (card->states[i] == NULL) {
				state = card->states[i] = (struct i810_state *)
					kmalloc(sizeof(struct i810_state), GFP_KERNEL);
				if (state == NULL)
					return -ENOMEM;
				memset(state, 0, sizeof(struct i810_state));
				dmabuf = &state->dmabuf;
				goto found_virt;
			}
		}
		card = card->next;
	}
	/* no more virtual channel avaiable */
	if (!state)
		return -ENODEV;

 found_virt:
	/* found a free virtual channel, allocate hardware channels */
	if(file->f_mode & FMODE_READ)
		dmabuf->channel = card->alloc_rec_pcm_channel(card);
	else
		dmabuf->channel = card->alloc_pcm_channel(card);
		
	if (dmabuf->channel == NULL) {
		kfree (card->states[i]);
		card->states[i] = NULL;;
		return -ENODEV;
	}

	/* initialize the virtual channel */
	state->virt = i;
	state->card = card;
	state->magic = I810_STATE_MAGIC;
	init_waitqueue_head(&dmabuf->wait);
	init_MUTEX(&state->open_sem);
	file->private_data = state;

	down(&state->open_sem);

	/* set default sample format. According to OSS Programmer's Guide  /dev/dsp
	   should be default to unsigned 8-bits, mono, with sample rate 8kHz and
	   /dev/dspW will accept 16-bits sample */
	if (file->f_mode & FMODE_WRITE) {
		dmabuf->fmt &= ~I810_FMT_MASK;
		dmabuf->fmt |= I810_FMT_16BIT;
		dmabuf->ossfragshift = 0;
		dmabuf->ossmaxfrags  = 0;
		dmabuf->subdivision  = 0;
		i810_set_dac_rate(state, 48000);
	}

	if (file->f_mode & FMODE_READ) {
		dmabuf->fmt &= ~I810_FMT_MASK;
		dmabuf->fmt |= I810_FMT_16BIT;
		dmabuf->ossfragshift = 0;
		dmabuf->ossmaxfrags  = 0;
		dmabuf->subdivision  = 0;
		i810_set_adc_rate(state, 48000);
	}

	state->open_mode |= file->f_mode & (FMODE_READ | FMODE_WRITE);
	up(&state->open_sem);

	return 0;
}

static int i810_release(struct inode *inode, struct file *file)
{
	struct i810_state *state = (struct i810_state *)file->private_data;
	struct dmabuf *dmabuf = &state->dmabuf;

	lock_kernel();
	if (file->f_mode & FMODE_WRITE) {
		i810_clear_tail(state);
		drain_dac(state, file->f_flags & O_NONBLOCK);
	}

	/* stop DMA state machine and free DMA buffers/channels */
	down(&state->open_sem);

	if (file->f_mode & FMODE_WRITE) {
		stop_dac(state);
		dealloc_dmabuf(state);
		state->card->free_pcm_channel(state->card, dmabuf->channel->num);
	}
	if (file->f_mode & FMODE_READ) {
		stop_adc(state);
		dealloc_dmabuf(state);
		state->card->free_pcm_channel(state->card, dmabuf->channel->num);
	}

	/* we're covered by the open_sem */
	up(&state->open_sem);
	
	kfree(state->card->states[state->virt]);
	state->card->states[state->virt] = NULL;
	unlock_kernel();

	return 0;
}

static /*const*/ struct file_operations i810_audio_fops = {
	owner:		THIS_MODULE,
	llseek:		i810_llseek,
	read:		i810_read,
	write:		i810_write,
	poll:		i810_poll,
	ioctl:		i810_ioctl,
	mmap:		i810_mmap,
	open:		i810_open,
	release:	i810_release,
};

/* Write AC97 codec registers */

static u16 i810_ac97_get(struct ac97_codec *dev, u8 reg)
{
	struct i810_card *card = dev->private_data;
	int count = 100;

	while(count-- && (inb(card->iobase + CAS) & 1)) 
		udelay(1);
	return inw(card->ac97base + (reg&0x7f));
}

static void i810_ac97_set(struct ac97_codec *dev, u8 reg, u16 data)
{
	struct i810_card *card = dev->private_data;
	int count = 100;

	while(count-- && (inb(card->iobase + CAS) & 1)) 
		udelay(1);
	outw(data, card->ac97base + (reg&0x7f));
}


/* OSS /dev/mixer file operation methods */

static int i810_open_mixdev(struct inode *inode, struct file *file)
{
	int i;
	int minor = MINOR(inode->i_rdev);
	struct i810_card *card = devs;

	for (card = devs; card != NULL; card = card->next)
		for (i = 0; i < NR_AC97; i++)
			if (card->ac97_codec[i] != NULL &&
			    card->ac97_codec[i]->dev_mixer == minor)
				goto match;

	if (!card)
		return -ENODEV;

 match:
	file->private_data = card->ac97_codec[i];

	return 0;
}

static int i810_ioctl_mixdev(struct inode *inode, struct file *file, unsigned int cmd,
				unsigned long arg)
{
	struct ac97_codec *codec = (struct ac97_codec *)file->private_data;

	return codec->mixer_ioctl(codec, cmd, arg);
}

static /*const*/ struct file_operations i810_mixer_fops = {
	owner:		THIS_MODULE,
	llseek:		i810_llseek,
	ioctl:		i810_ioctl_mixdev,
	open:		i810_open_mixdev,
};

/* AC97 codec initialisation. */
static int __init i810_ac97_init(struct i810_card *card)
{
	int num_ac97 = 0;
	int ready_2nd = 0;
	struct ac97_codec *codec;
	u16 eid;
	int i=0;
	u32 reg;

	reg = inl(card->iobase + GLOB_CNT);
	
	if((reg&2)==0)	/* Cold required */
		reg|=2;
	else
		reg|=4;	/* Warm */
		
	reg&=~8;	/* ACLink on */
	outl(reg , card->iobase + GLOB_CNT);
	
	while(i<10)
	{
		if((inl(card->iobase+GLOB_CNT)&4)==0)
			break;
		current->state = TASK_UNINTERRUPTIBLE;
		schedule_timeout(HZ/20);
		i++;
	}
	if(i==10)
	{
		printk(KERN_ERR "i810_audio: AC'97 reset failed.\n");
		return 0;
	}

	current->state = TASK_UNINTERRUPTIBLE;
	schedule_timeout(HZ/5);
		
	inw(card->ac97base);

	for (num_ac97 = 0; num_ac97 < NR_AC97; num_ac97++) {
		if ((codec = kmalloc(sizeof(struct ac97_codec), GFP_KERNEL)) == NULL)
			return -ENOMEM;
		memset(codec, 0, sizeof(struct ac97_codec));

		/* initialize some basic codec information, other fields will be filled
		   in ac97_probe_codec */
		codec->private_data = card;
		codec->id = num_ac97;

		codec->codec_read = i810_ac97_get;
		codec->codec_write = i810_ac97_set;
	
		if (ac97_probe_codec(codec) == 0)
			break;

		eid = i810_ac97_get(codec, AC97_EXTENDED_ID);
		
		if(eid==0xFFFFFF)
		{
			printk(KERN_WARNING "i810_audio: no codec attached ?\n");
			kfree(codec);
			break;
		}
		
		card->ac97_features = eid;
				
		/* Now check the codec for useful features to make up for
		   the dumbness of the 810 hardware engine */

		if(!(eid&0x0001))
			printk(KERN_WARNING "i810_audio: only 48Khz playback available.\n");
		else
		{
			/* Enable variable rate mode */
			i810_ac97_set(codec, AC97_EXTENDED_STATUS, 9);
			i810_ac97_set(codec,AC97_EXTENDED_STATUS,
				i810_ac97_get(codec, AC97_EXTENDED_STATUS)|0xE800);
			/* power up everything, modify this when implementing power saving */
			i810_ac97_set(codec, AC97_POWER_CONTROL,
				i810_ac97_get(codec, AC97_POWER_CONTROL) & ~0x7f00);
			/* wait for analog ready */
		        for (i=10;
			     i && ((i810_ac97_get(codec, AC97_POWER_CONTROL) & 0xf) != 0xf);
			     i--)
			{
				current->state = TASK_UNINTERRUPTIBLE;
				schedule_timeout(HZ/20);
			}

			if(!(i810_ac97_get(codec, AC97_EXTENDED_STATUS)&1))
			{
				printk(KERN_WARNING "i810_audio: Codec refused to allow VRA, using 48Khz only.\n");
				card->ac97_features&=~1;
			}
		}
   		
		if ((codec->dev_mixer = register_sound_mixer(&i810_mixer_fops, -1)) < 0) {
			printk(KERN_ERR "i810_audio: couldn't register mixer!\n");
			kfree(codec);
			break;
		}

		card->ac97_codec[num_ac97] = codec;

		/* if there is no secondary codec at all, don't probe any more */
		if (!ready_2nd)
			return num_ac97+1;
	}
	return num_ac97;
}

/* install the driver, we do not allocate hardware channel nor DMA buffer now, they are defered 
   untill "ACCESS" time (in prog_dmabuf called by open/read/write/ioctl/mmap) */
   
static int __init i810_probe(struct pci_dev *pci_dev, const struct pci_device_id *pci_id)
{
	struct i810_card *card;

	if (!pci_dma_supported(pci_dev, I810_DMA_MASK)) {
		printk(KERN_ERR "intel810: architecture does not support"
		       " 32bit PCI busmaster DMA\n");
		return -ENODEV;
	}

	if (pci_enable_device(pci_dev))
		return -EIO;
	if ((card = kmalloc(sizeof(struct i810_card), GFP_KERNEL)) == NULL) {
		printk(KERN_ERR "i810_audio: out of memory\n");
		return -ENOMEM;
	}
	memset(card, 0, sizeof(*card));

	card->iobase = pci_resource_start (pci_dev, 1);
	card->ac97base = pci_resource_start (pci_dev, 0);
	card->pci_dev = pci_dev;
	card->pci_id = pci_id->device;
	card->irq = pci_dev->irq;
	card->next = devs;
	card->magic = I810_CARD_MAGIC;
	spin_lock_init(&card->lock);
	devs = card;

	pci_set_master(pci_dev);

	printk(KERN_INFO "i810: %s found at IO 0x%04lx and 0x%04lx, IRQ %d\n",
	       card_names[pci_id->driver_data], card->iobase, card->ac97base, 
	       card->irq);

	card->alloc_pcm_channel = i810_alloc_pcm_channel;
	card->alloc_rec_pcm_channel = i810_alloc_rec_pcm_channel;
	card->free_pcm_channel = i810_free_pcm_channel;

	/* claim our iospace and irq */
	request_region(card->iobase, 64, card_names[pci_id->driver_data]);
	request_region(card->ac97base, 256, card_names[pci_id->driver_data]);

	if (request_irq(card->irq, &i810_interrupt, SA_SHIRQ,
			card_names[pci_id->driver_data], card)) {
		printk(KERN_ERR "i810_audio: unable to allocate irq %d\n", card->irq);
		release_region(card->iobase, 64);
		release_region(card->ac97base, 256);
		kfree(card);
		return -ENODEV;
	}
	/* register /dev/dsp */
	if ((card->dev_audio = register_sound_dsp(&i810_audio_fops, -1)) < 0) {
		printk(KERN_ERR "i810_audio: couldn't register DSP device!\n");
		release_region(card->iobase, 64);
		release_region(card->ac97base, 256);
		free_irq(card->irq, card);
		kfree(card);
		return -ENODEV;
	}


	/* initialize AC97 codec and register /dev/mixer */
	if (i810_ac97_init(card) <= 0) {
		unregister_sound_dsp(card->dev_audio);
		release_region(card->iobase, 64);
		release_region(card->ac97base, 256);
		free_irq(card->irq, card);
		kfree(card);
		return -ENODEV;
	}
	pci_dev->driver_data = card;
	pci_dev->dma_mask = I810_DMA_MASK;
	return 0;
}

static void __exit i810_remove(struct pci_dev *pci_dev)
{
	int i;
	struct i810_card *card = pci_dev->driver_data;
	/* free hardware resources */
	free_irq(card->irq, devs);
	release_region(card->iobase, 64);
	release_region(card->ac97base, 256);

	/* unregister audio devices */
	for (i = 0; i < NR_AC97; i++)
		if (devs->ac97_codec[i] != NULL) {
			unregister_sound_mixer(card->ac97_codec[i]->dev_mixer);
			kfree (card->ac97_codec[i]);
		}
	unregister_sound_dsp(card->dev_audio);
	kfree(card);
}


MODULE_AUTHOR("");
MODULE_DESCRIPTION("Intel 810 audio support");
MODULE_PARM(ftsodell, "i");
MODULE_PARM(clocking, "i");

#define I810_MODULE_NAME "intel810_audio"

static struct pci_driver i810_pci_driver = {
	name:		I810_MODULE_NAME,
	id_table:	i810_pci_tbl,
	probe:		i810_probe,
	remove:		i810_remove,
};

static int __init i810_init_module (void)
{
	if (!pci_present())   /* No PCI bus in this machine! */
		return -ENODEV;

	if(ftsodell==1)
		clocking=41194;
		
	printk(KERN_INFO "Intel 810 + AC97 Audio, version "
	       DRIVER_VERSION ", " __TIME__ " " __DATE__ "\n");

	if (!pci_register_driver(&i810_pci_driver)) {
		pci_unregister_driver(&i810_pci_driver);
                return -ENODEV;
	}
	return 0;
}

static void __exit i810_cleanup_module (void)
{
	pci_unregister_driver(&i810_pci_driver);
}

module_init(i810_init_module);
module_exit(i810_cleanup_module);