i810_audio.c

宋宝华的《Linux设备驱动开发详解》第一版的源代码

	if(card->pci_id == PCI_DEVICE_ID_SI_7012)
		I810_IOWRITEB( I810_IOREADB(card, PI_PICB), card, PI_PICB );
	else
		I810_IOWRITEB( I810_IOREADB(card, PI_SR), card, PI_SR );
	I810_IOWRITEL( I810_IOREADL(card, GLOB_STA) & INT_PI, card, GLOB_STA);
}

static void stop_adc(struct i810_state *state)
{
	struct i810_card *card = state->card;
	unsigned long flags;

	spin_lock_irqsave(&card->lock, flags);
	__stop_adc(state);
	spin_unlock_irqrestore(&card->lock, flags);
}

static inline void __start_adc(struct i810_state *state)
{
	struct dmabuf *dmabuf = &state->dmabuf;

	if (dmabuf->count < dmabuf->dmasize && dmabuf->ready && !dmabuf->enable &&
	    (dmabuf->trigger & PCM_ENABLE_INPUT)) {
		dmabuf->enable |= ADC_RUNNING;
		// Interrupt enable, LVI enable, DMA enable
		I810_IOWRITEB(0x10 | 0x04 | 0x01, state->card, PI_CR);
	}
}

static void start_adc(struct i810_state *state)
{
	struct i810_card *card = state->card;
	unsigned long flags;

	spin_lock_irqsave(&card->lock, flags);
	__start_adc(state);
	spin_unlock_irqrestore(&card->lock, flags);
}

/* stop playback (lock held) */
static inline void __stop_dac(struct i810_state *state)
{
	struct dmabuf *dmabuf = &state->dmabuf;
	struct i810_card *card = state->card;

	dmabuf->enable &= ~DAC_RUNNING;
	I810_IOWRITEB(0, card, PO_CR);
	// wait for the card to acknowledge shutdown
	while( I810_IOREADB(card, PO_CR) != 0 ) ;
	// now clear any latent interrupt bits (like the halt bit)
	if(card->pci_id == PCI_DEVICE_ID_SI_7012)
		I810_IOWRITEB( I810_IOREADB(card, PO_PICB), card, PO_PICB );
	else
		I810_IOWRITEB( I810_IOREADB(card, PO_SR), card, PO_SR );
	I810_IOWRITEL( I810_IOREADL(card, GLOB_STA) & INT_PO, card, GLOB_STA);
}

static void stop_dac(struct i810_state *state)
{
	struct i810_card *card = state->card;
	unsigned long flags;

	spin_lock_irqsave(&card->lock, flags);
	__stop_dac(state);
	spin_unlock_irqrestore(&card->lock, flags);
}	

static inline void __start_dac(struct i810_state *state)
{
	struct dmabuf *dmabuf = &state->dmabuf;

	if (dmabuf->count > 0 && dmabuf->ready && !dmabuf->enable &&
	    (dmabuf->trigger & PCM_ENABLE_OUTPUT)) {
		dmabuf->enable |= DAC_RUNNING;
		// Interrupt enable, LVI enable, DMA enable
		I810_IOWRITEB(0x10 | 0x04 | 0x01, state->card, PO_CR);
	}
}
static void start_dac(struct i810_state *state)
{
	struct i810_card *card = state->card;
	unsigned long flags;

	spin_lock_irqsave(&card->lock, flags);
	__start_dac(state);
	spin_unlock_irqrestore(&card->lock, flags);
}

#define DMABUF_DEFAULTORDER (16-PAGE_SHIFT)
#define DMABUF_MINORDER 1

/* allocate DMA buffer, playback and recording buffer should be allocated separately */
static int alloc_dmabuf(struct i810_state *state)
{
	struct dmabuf *dmabuf = &state->dmabuf;
	void *rawbuf= NULL;
	int order, size;
	struct page *page, *pend;

	/* If we don't have any oss frag params, then use our default ones */
	if(dmabuf->ossmaxfrags == 0)
		dmabuf->ossmaxfrags = 4;
	if(dmabuf->ossfragsize == 0)
		dmabuf->ossfragsize = (PAGE_SIZE<<DMABUF_DEFAULTORDER)/dmabuf->ossmaxfrags;
	size = dmabuf->ossfragsize * dmabuf->ossmaxfrags;

	if(dmabuf->rawbuf && (PAGE_SIZE << dmabuf->buforder) == size)
		return 0;
	/* alloc enough to satisfy the oss params */
	for (order = DMABUF_DEFAULTORDER; order >= DMABUF_MINORDER; order--) {
		if ( (PAGE_SIZE<<order) > size )
			continue;
		if ((rawbuf = pci_alloc_consistent(state->card->pci_dev,
						   PAGE_SIZE << order,
						   &dmabuf->dma_handle)))
			break;
	}
	if (!rawbuf)
		return -ENOMEM;


#ifdef DEBUG
	printk("i810_audio: allocated %ld (order = %d) bytes at %p\n",
	       PAGE_SIZE << order, order, rawbuf);
#endif

	dmabuf->ready  = dmabuf->mapped = 0;
	dmabuf->rawbuf = rawbuf;
	dmabuf->buforder = order;
	
	/* now mark the pages as reserved; otherwise remap_pfn_range doesn't do what we want */
	pend = virt_to_page(rawbuf + (PAGE_SIZE << order) - 1);
	for (page = virt_to_page(rawbuf); page <= pend; page++)
		SetPageReserved(page);

	return 0;
}

/* free DMA buffer */
static void dealloc_dmabuf(struct i810_state *state)
{
	struct dmabuf *dmabuf = &state->dmabuf;
	struct page *page, *pend;

	if (dmabuf->rawbuf) {
		/* undo marking the pages as reserved */
		pend = virt_to_page(dmabuf->rawbuf + (PAGE_SIZE << dmabuf->buforder) - 1);
		for (page = virt_to_page(dmabuf->rawbuf); page <= pend; page++)
			ClearPageReserved(page);
		pci_free_consistent(state->card->pci_dev, PAGE_SIZE << dmabuf->buforder,
				    dmabuf->rawbuf, dmabuf->dma_handle);
	}
	dmabuf->rawbuf = NULL;
	dmabuf->mapped = dmabuf->ready = 0;
}

static int prog_dmabuf(struct i810_state *state, unsigned rec)
{
	struct dmabuf *dmabuf = &state->dmabuf;
	struct i810_channel *c;
	struct sg_item *sg;
	unsigned long flags;
	int ret;
	unsigned fragint;
	int i;

	spin_lock_irqsave(&state->card->lock, flags);
	if(dmabuf->enable & DAC_RUNNING)
		__stop_dac(state);
	if(dmabuf->enable & ADC_RUNNING)
		__stop_adc(state);
	dmabuf->total_bytes = 0;
	dmabuf->count = dmabuf->error = 0;
	dmabuf->swptr = dmabuf->hwptr = 0;
	spin_unlock_irqrestore(&state->card->lock, flags);

	/* allocate DMA buffer, let alloc_dmabuf determine if we are already
	 * allocated well enough or if we should replace the current buffer
	 * (assuming one is already allocated, if it isn't, then allocate it).
	 */
	if ((ret = alloc_dmabuf(state)))
		return ret;

	/* FIXME: figure out all this OSS fragment stuff */
	/* I did, it now does what it should according to the OSS API.  DL */
	/* We may not have realloced our dmabuf, but the fragment size to
	 * fragment number ratio may have changed, so go ahead and reprogram
	 * things
	 */
	dmabuf->dmasize = PAGE_SIZE << dmabuf->buforder;
	dmabuf->numfrag = SG_LEN;
	dmabuf->fragsize = dmabuf->dmasize/dmabuf->numfrag;
	dmabuf->fragsamples = dmabuf->fragsize >> 1;
	dmabuf->fragshift = ffs(dmabuf->fragsize) - 1;
	dmabuf->userfragsize = dmabuf->ossfragsize;
	dmabuf->userfrags = dmabuf->dmasize/dmabuf->ossfragsize;

	memset(dmabuf->rawbuf, 0, dmabuf->dmasize);

	if(dmabuf->ossmaxfrags == 4) {
		fragint = 8;
	} else if (dmabuf->ossmaxfrags == 8) {
		fragint = 4;
	} else if (dmabuf->ossmaxfrags == 16) {
		fragint = 2;
	} else {
		fragint = 1;
	}
	/*
	 *	Now set up the ring 
	 */
	if(dmabuf->read_channel)
		c = dmabuf->read_channel;
	else
		c = dmabuf->write_channel;
	while(c != NULL) {
		sg=&c->sg[0];
		/*
		 *	Load up 32 sg entries and take an interrupt at half
		 *	way (we might want more interrupts later..) 
		 */
	  
		for(i=0;i<dmabuf->numfrag;i++)
		{
			sg->busaddr=(u32)dmabuf->dma_handle+dmabuf->fragsize*i;
			// the card will always be doing 16bit stereo
			sg->control=dmabuf->fragsamples;
			if(state->card->pci_id == PCI_DEVICE_ID_SI_7012)
				sg->control <<= 1;
			sg->control|=CON_BUFPAD;
			// set us up to get IOC interrupts as often as needed to
			// satisfy numfrag requirements, no more
			if( ((i+1) % fragint) == 0) {
				sg->control|=CON_IOC;
			}
			sg++;
		}
		spin_lock_irqsave(&state->card->lock, flags);
		I810_IOWRITEB(2, state->card, c->port+OFF_CR);   /* reset DMA machine */
		while( I810_IOREADB(state->card, c->port+OFF_CR) & 0x02 ) ;
		I810_IOWRITEL((u32)state->card->chandma +
		    c->num*sizeof(struct i810_channel),
		    state->card, c->port+OFF_BDBAR);
		CIV_TO_LVI(state->card, c->port, 0);

		spin_unlock_irqrestore(&state->card->lock, flags);

		if(c != dmabuf->write_channel)
			c = dmabuf->write_channel;
		else
			c = NULL;
	}
	
	/* set the ready flag for the dma buffer */
	dmabuf->ready = 1;

#ifdef DEBUG
	printk("i810_audio: prog_dmabuf, sample rate = %d, format = %d,\n\tnumfrag = %d, "
	       "fragsize = %d dmasize = %d\n",
	       dmabuf->rate, dmabuf->fmt, dmabuf->numfrag,
	       dmabuf->fragsize, dmabuf->dmasize);
#endif

	return 0;
}

static void __i810_update_lvi(struct i810_state *state, int rec)
{
	struct dmabuf *dmabuf = &state->dmabuf;
	int x, port;
	int trigger;
	int count, fragsize;
	void (*start)(struct i810_state *);

	count = dmabuf->count;
	if (rec) {
		port = dmabuf->read_channel->port;
		trigger = PCM_ENABLE_INPUT;
		start = __start_adc;
		count = dmabuf->dmasize - count;
	} else {
		port = dmabuf->write_channel->port;
		trigger = PCM_ENABLE_OUTPUT;
		start = __start_dac;
	}

	/* Do not process partial fragments. */
	fragsize = dmabuf->fragsize;
	if (count < fragsize)
		return;

	/* if we are currently stopped, then our CIV is actually set to our
	 * *last* sg segment and we are ready to wrap to the next.  However,
	 * if we set our LVI to the last sg segment, then it won't wrap to
	 * the next sg segment, it won't even get a start.  So, instead, when
	 * we are stopped, we set both the LVI value and also we increment
	 * the CIV value to the next sg segment to be played so that when
	 * we call start, things will operate properly.  Since the CIV can't
	 * be written to directly for this purpose, we set the LVI to CIV + 1
	 * temporarily.  Once the engine has started we set the LVI to its
	 * final value.
	 */
	if (!dmabuf->enable && dmabuf->ready) {
		if (!(dmabuf->trigger & trigger))
			return;

		CIV_TO_LVI(state->card, port, 1);

		start(state);
		while (!(I810_IOREADB(state->card, port + OFF_CR) & ((1<<4) | (1<<2))))
			;
	}

	/* MASKP2(swptr, fragsize) - 1 is the tail of our transfer */
	x = MODULOP2(MASKP2(dmabuf->swptr, fragsize) - 1, dmabuf->dmasize);
	x >>= dmabuf->fragshift;
	I810_IOWRITEB(x, state->card, port + OFF_LVI);
}

static void i810_update_lvi(struct i810_state *state, int rec)
{
	struct dmabuf *dmabuf = &state->dmabuf;
	unsigned long flags;

	if(!dmabuf->ready)
		return;
	spin_lock_irqsave(&state->card->lock, flags);
	__i810_update_lvi(state, rec);
	spin_unlock_irqrestore(&state->card->lock, flags);
}

/* update buffer manangement pointers, especially, dmabuf->count and dmabuf->hwptr */
static void i810_update_ptr(struct i810_state *state)
{
	struct dmabuf *dmabuf = &state->dmabuf;
	unsigned hwptr;
	unsigned fragmask, dmamask;
	int diff;

	fragmask = MASKP2(~0, dmabuf->fragsize);
	dmamask = MODULOP2(~0, dmabuf->dmasize);

	/* error handling and process wake up for ADC */
	if (dmabuf->enable == ADC_RUNNING) {
		/* update hardware pointer */
		hwptr = i810_get_dma_addr(state, 1) & fragmask;
		diff = (hwptr - dmabuf->hwptr) & dmamask;
#if defined(DEBUG_INTERRUPTS) || defined(DEBUG_MMAP)
		printk("ADC HWP %d,%d,%d\n", hwptr, dmabuf->hwptr, diff);
#endif
		dmabuf->hwptr = hwptr;
		dmabuf->total_bytes += diff;
		dmabuf->count += diff;
		if (dmabuf->count > dmabuf->dmasize) {
			/* buffer underrun or buffer overrun */
			/* this is normal for the end of a read */
			/* only give an error if we went past the */
			/* last valid sg entry */
			if (GET_CIV(state->card, PI_BASE) !=
			    GET_LVI(state->card, PI_BASE)) {
				printk(KERN_WARNING "i810_audio: DMA overrun on read\n");
				dmabuf->error++;
			}
		}
		if (diff)
			wake_up(&dmabuf->wait);
	}
	/* error handling and process wake up for DAC */
	if (dmabuf->enable == DAC_RUNNING) {
		/* update hardware pointer */
		hwptr = i810_get_dma_addr(state, 0) & fragmask;
		diff = (hwptr - dmabuf->hwptr) & dmamask;
#if defined(DEBUG_INTERRUPTS) || defined(DEBUG_MMAP)
		printk("DAC HWP %d,%d,%d\n", hwptr, dmabuf->hwptr, diff);
#endif
		dmabuf->hwptr = hwptr;
		dmabuf->total_bytes += diff;
		dmabuf->count -= diff;
		if (dmabuf->count < 0) {
			/* buffer underrun or buffer overrun */
			/* this is normal for the end of a write */
			/* only give an error if we went past the */
			/* last valid sg entry */
			if (GET_CIV(state->card, PO_BASE) !=
			    GET_LVI(state->card, PO_BASE)) {
				printk(KERN_WARNING "i810_audio: DMA overrun on write\n");
				printk("i810_audio: CIV %d, LVI %d, hwptr %x, "
					"count %d\n",
					GET_CIV(state->card, PO_BASE),
					GET_LVI(state->card, PO_BASE),
					dmabuf->hwptr, dmabuf->count);
				dmabuf->error++;
			}
		}
		if (diff)
			wake_up(&dmabuf->wait);
	}
}

static inline int i810_get_free_write_space(struct i810_state *state)
{
	struct dmabuf *dmabuf = &state->dmabuf;
	int free;

	i810_update_ptr(state);
	// catch underruns during playback
	if (dmabuf->count < 0) {
		dmabuf->count = 0;
		dmabuf->swptr = dmabuf->hwptr;
	}
	free = dmabuf->dmasize - dmabuf->count;
	if(free < 0)
		return(0);
	return(free);
}

static inline int i810_get_available_read_data(struct i810_state *state)
{
	struct dmabuf *dmabuf = &state->dmabuf;
	int avail;

	i810_update_ptr(state);
	// catch overruns during record
	if (dmabuf->count > dmabuf->dmasize) {
		dmabuf->count = dmabuf->dmasize;
		dmabuf->swptr = dmabuf->hwptr;
	}
	avail = dmabuf->count;
	if(avail < 0)
		return(0);
	return(avail);
}

static inline void fill_partial_frag(struct dmabuf *dmabuf)
{
	unsigned fragsize;
	unsigned swptr, len;

	fragsize = dmabuf->fragsize;
	swptr = dmabuf->swptr;
	len = fragsize - MODULOP2(dmabuf->swptr, fragsize);
	if (len == fragsize)
		return;

	memset(dmabuf->rawbuf + swptr, '\0', len);
	dmabuf->swptr = MODULOP2(swptr + len, dmabuf->dmasize);
	dmabuf->count += len;
}

static int drain_dac(struct i810_state *state, int signals_allowed)
{
	DECLARE_WAITQUEUE(wait, current);
	struct dmabuf *dmabuf = &state->dmabuf;
	unsigned long flags;