dmabuf.c

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/*
 * sound/dmabuf.c
 *
 * The DMA buffer manager for digitized voice applications
 */
/*
 * Copyright (C) by Hannu Savolainen 1993-1997
 *
 * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
 * Version 2 (June 1991). See the "COPYING" file distributed with this software
 * for more info.
 *
 * Thomas Sailer   : moved several static variables into struct audio_operations
 *                   (which is grossly misnamed btw.) because they have the same
 *                   lifetime as the rest in there and dynamic allocation saves
 *                   12k or so
 * Thomas Sailer   : remove {in,out}_sleep_flag. It was used for the sleeper to
 *                   determine if it was woken up by the expiring timeout or by
 *                   an explicit wake_up. The return value from schedule_timeout
 *		     can be used instead; if 0, the wakeup was due to the timeout.
 *
 * Rob Riggs		Added persistent DMA buffers (1998/10/17)
 */

#define BE_CONSERVATIVE
#define SAMPLE_ROUNDUP 0

#include "sound_config.h"
#include <linux/wrapper.h>

#define DMAP_FREE_ON_CLOSE      0
#define DMAP_KEEP_ON_CLOSE      1
extern int sound_dmap_flag;

static void dma_reset_output(int dev);
static void dma_reset_input(int dev);
static int local_start_dma(struct audio_operations *adev, unsigned long physaddr, int count, int dma_mode);



static int debugmem = 0;	/* switched off by default */
static int dma_buffsize = DSP_BUFFSIZE;

static long dmabuf_timeout(struct dma_buffparms *dmap)
{
	long tmout;

	tmout = (dmap->fragment_size * HZ) / dmap->data_rate;
	tmout += HZ / 5;	/* Some safety distance */
	if (tmout < (HZ / 2))
		tmout = HZ / 2;
	if (tmout > 20 * HZ)
		tmout = 20 * HZ;
	return tmout;
}

static int sound_alloc_dmap(struct dma_buffparms *dmap)
{
	char *start_addr, *end_addr;
	int dma_pagesize;
	int sz, size;
	struct page *page;

	dmap->mapping_flags &= ~DMA_MAP_MAPPED;

	if (dmap->raw_buf != NULL)
		return 0;	/* Already done */
	if (dma_buffsize < 4096)
		dma_buffsize = 4096;
	dma_pagesize = (dmap->dma < 4) ? (64 * 1024) : (128 * 1024);
	
	/*
	 *	Now check for the Cyrix problem.
	 */
	 
	if(isa_dma_bridge_buggy==2)
		dma_pagesize=32768;
	 
	dmap->raw_buf = NULL;
	dmap->buffsize = dma_buffsize;
	if (dmap->buffsize > dma_pagesize)
		dmap->buffsize = dma_pagesize;
	start_addr = NULL;
	/*
	 * Now loop until we get a free buffer. Try to get smaller buffer if
	 * it fails. Don't accept smaller than 8k buffer for performance
	 * reasons.
	 */
	while (start_addr == NULL && dmap->buffsize > PAGE_SIZE) {
		for (sz = 0, size = PAGE_SIZE; size < dmap->buffsize; sz++, size <<= 1);
		dmap->buffsize = PAGE_SIZE * (1 << sz);
		start_addr = (char *) __get_free_pages(GFP_ATOMIC|GFP_DMA, sz);
		if (start_addr == NULL)
			dmap->buffsize /= 2;
	}

	if (start_addr == NULL) {
		printk(KERN_WARNING "Sound error: Couldn't allocate DMA buffer\n");
		return -ENOMEM;
	} else {
		/* make some checks */
		end_addr = start_addr + dmap->buffsize - 1;

		if (debugmem)
			printk(KERN_DEBUG "sound: start 0x%lx, end 0x%lx\n", (long) start_addr, (long) end_addr);
		
		/* now check if it fits into the same dma-pagesize */

		if (((long) start_addr & ~(dma_pagesize - 1)) != ((long) end_addr & ~(dma_pagesize - 1))
		    || end_addr >= (char *) (MAX_DMA_ADDRESS)) {
			printk(KERN_ERR "sound: Got invalid address 0x%lx for %db DMA-buffer\n", (long) start_addr, dmap->buffsize);
			return -EFAULT;
		}
	}
	dmap->raw_buf = start_addr;
	dmap->raw_buf_phys = virt_to_bus(start_addr);

	for (page = virt_to_page(start_addr); page <= virt_to_page(end_addr); page++)
		mem_map_reserve(page);
	return 0;
}

static void sound_free_dmap(struct dma_buffparms *dmap)
{
	int sz, size;
	struct page *page;
	unsigned long start_addr, end_addr;

	if (dmap->raw_buf == NULL)
		return;
	if (dmap->mapping_flags & DMA_MAP_MAPPED)
		return;		/* Don't free mmapped buffer. Will use it next time */
	for (sz = 0, size = PAGE_SIZE; size < dmap->buffsize; sz++, size <<= 1);

	start_addr = (unsigned long) dmap->raw_buf;
	end_addr = start_addr + dmap->buffsize;

	for (page = virt_to_page(start_addr); page <= virt_to_page(end_addr); page++)
		mem_map_unreserve(page);

	free_pages((unsigned long) dmap->raw_buf, sz);
	dmap->raw_buf = NULL;
}


/* Intel version !!!!!!!!! */

static int sound_start_dma(struct dma_buffparms *dmap, unsigned long physaddr, int count, int dma_mode)
{
	unsigned long flags;
	int chan = dmap->dma;

	/* printk( "Start DMA%d %d, %d\n",  chan,  (int)(physaddr-dmap->raw_buf_phys),  count); */

	flags = claim_dma_lock();
	disable_dma(chan);
	clear_dma_ff(chan);
	set_dma_mode(chan, dma_mode);
	set_dma_addr(chan, physaddr);
	set_dma_count(chan, count);
	enable_dma(chan);
	release_dma_lock(flags);

	return 0;
}

static void dma_init_buffers(struct dma_buffparms *dmap)
{
	dmap->qlen = dmap->qhead = dmap->qtail = dmap->user_counter = 0;
	dmap->byte_counter = 0;
	dmap->max_byte_counter = 8000 * 60 * 60;
	dmap->bytes_in_use = dmap->buffsize;

	dmap->dma_mode = DMODE_NONE;
	dmap->mapping_flags = 0;
	dmap->neutral_byte = 0x80;
	dmap->data_rate = 8000;
	dmap->cfrag = -1;
	dmap->closing = 0;
	dmap->nbufs = 1;
	dmap->flags = DMA_BUSY;	/* Other flags off */
}

static int open_dmap(struct audio_operations *adev, int mode, struct dma_buffparms *dmap)
{
	int err;
	
	if (dmap->flags & DMA_BUSY)
		return -EBUSY;
	if ((err = sound_alloc_dmap(dmap)) < 0)
		return err;

	if (dmap->raw_buf == NULL) {
		printk(KERN_WARNING "Sound: DMA buffers not available\n");
		return -ENOSPC;	/* Memory allocation failed during boot */
	}
	if (dmap->dma >= 0 && sound_open_dma(dmap->dma, adev->name)) {
		printk(KERN_WARNING "Unable to grab(2) DMA%d for the audio driver\n", dmap->dma);
		return -EBUSY;
	}
	dma_init_buffers(dmap);
	dmap->open_mode = mode;
	dmap->subdivision = dmap->underrun_count = 0;
	dmap->fragment_size = 0;
	dmap->max_fragments = 65536;	/* Just a large value */
	dmap->byte_counter = 0;
	dmap->max_byte_counter = 8000 * 60 * 60;
	dmap->applic_profile = APF_NORMAL;
	dmap->needs_reorg = 1;
	dmap->audio_callback = NULL;
	dmap->callback_parm = 0;
	return 0;
}

static void close_dmap(struct audio_operations *adev, struct dma_buffparms *dmap)
{
	unsigned long flags;
	
	if (dmap->dma >= 0) {
		sound_close_dma(dmap->dma);
		flags=claim_dma_lock();
		disable_dma(dmap->dma);
		release_dma_lock(flags);
	}
	if (dmap->flags & DMA_BUSY)
		dmap->dma_mode = DMODE_NONE;
	dmap->flags &= ~DMA_BUSY;
	
	if (sound_dmap_flag == DMAP_FREE_ON_CLOSE)
		sound_free_dmap(dmap);
}


static unsigned int default_set_bits(int dev, unsigned int bits)
{
	mm_segment_t fs = get_fs();

	set_fs(get_ds());
	audio_devs[dev]->d->ioctl(dev, SNDCTL_DSP_SETFMT, (caddr_t)&bits);
	set_fs(fs);
	return bits;
}

static int default_set_speed(int dev, int speed)
{
	mm_segment_t fs = get_fs();

	set_fs(get_ds());
	audio_devs[dev]->d->ioctl(dev, SNDCTL_DSP_SPEED, (caddr_t)&speed);
	set_fs(fs);
	return speed;
}

static short default_set_channels(int dev, short channels)
{
	int c = channels;
	mm_segment_t fs = get_fs();

	set_fs(get_ds());
	audio_devs[dev]->d->ioctl(dev, SNDCTL_DSP_CHANNELS, (caddr_t)&c);
	set_fs(fs);
	return c;
}

static void check_driver(struct audio_driver *d)
{
	if (d->set_speed == NULL)
		d->set_speed = default_set_speed;
	if (d->set_bits == NULL)
		d->set_bits = default_set_bits;
	if (d->set_channels == NULL)
		d->set_channels = default_set_channels;
}

int DMAbuf_open(int dev, int mode)
{
	struct audio_operations *adev = audio_devs[dev];
	int retval;
	struct dma_buffparms *dmap_in = NULL;
	struct dma_buffparms *dmap_out = NULL;

	if (!adev)
		  return -ENXIO;
	if (!(adev->flags & DMA_DUPLEX))
		adev->dmap_in = adev->dmap_out;
	check_driver(adev->d);

	if ((retval = adev->d->open(dev, mode)) < 0)
		return retval;
	dmap_out = adev->dmap_out;
	dmap_in = adev->dmap_in;
	if (dmap_in == dmap_out)
		adev->flags &= ~DMA_DUPLEX;

	if (mode & OPEN_WRITE) {
		if ((retval = open_dmap(adev, mode, dmap_out)) < 0) {
			adev->d->close(dev);
			return retval;
		}
	}
	adev->enable_bits = mode;

	if (mode == OPEN_READ || (mode != OPEN_WRITE && (adev->flags & DMA_DUPLEX))) {
		if ((retval = open_dmap(adev, mode, dmap_in)) < 0) {
			adev->d->close(dev);
			if (mode & OPEN_WRITE)
				close_dmap(adev, dmap_out);
			return retval;
		}
	}
	adev->open_mode = mode;
	adev->go = 1;

	adev->d->set_bits(dev, 8);
	adev->d->set_channels(dev, 1);
	adev->d->set_speed(dev, DSP_DEFAULT_SPEED);
	if (adev->dmap_out->dma_mode == DMODE_OUTPUT) 
		memset(adev->dmap_out->raw_buf, adev->dmap_out->neutral_byte,
		       adev->dmap_out->bytes_in_use);
	return 0;
}

void DMAbuf_reset(int dev)
{
	if (audio_devs[dev]->open_mode & OPEN_WRITE)
		dma_reset_output(dev);

	if (audio_devs[dev]->open_mode & OPEN_READ)
		dma_reset_input(dev);
}

static void dma_reset_output(int dev)
{
	struct audio_operations *adev = audio_devs[dev];
	unsigned long flags,f ;
	struct dma_buffparms *dmap = adev->dmap_out;

	if (!(dmap->flags & DMA_STARTED))	/* DMA is not active */
		return;

	/*
	 *	First wait until the current fragment has been played completely
	 */
	save_flags(flags);
	cli();
	adev->dmap_out->flags |= DMA_SYNCING;

	adev->dmap_out->underrun_count = 0;
	if (!signal_pending(current) && adev->dmap_out->qlen && 
	    adev->dmap_out->underrun_count == 0)
		interruptible_sleep_on_timeout(&adev->out_sleeper,
					       dmabuf_timeout(dmap));
	adev->dmap_out->flags &= ~(DMA_SYNCING | DMA_ACTIVE);

	/*
	 *	Finally shut the device off
	 */
	if (!(adev->flags & DMA_DUPLEX) || !adev->d->halt_output)
		adev->d->halt_io(dev);
	else
		adev->d->halt_output(dev);
	adev->dmap_out->flags &= ~DMA_STARTED;
	
	f=claim_dma_lock();
	clear_dma_ff(dmap->dma);
	disable_dma(dmap->dma);
	release_dma_lock(f);
	
	restore_flags(flags);
	dmap->byte_counter = 0;
	reorganize_buffers(dev, adev->dmap_out, 0);
	dmap->qlen = dmap->qhead = dmap->qtail = dmap->user_counter = 0;
}

static void dma_reset_input(int dev)
{
        struct audio_operations *adev = audio_devs[dev];
	unsigned long flags;
	struct dma_buffparms *dmap = adev->dmap_in;

	save_flags(flags);
	cli();
	if (!(adev->flags & DMA_DUPLEX) || !adev->d->halt_input)
		adev->d->halt_io(dev);
	else
		adev->d->halt_input(dev);
	adev->dmap_in->flags &= ~DMA_STARTED;
	restore_flags(flags);

	dmap->qlen = dmap->qhead = dmap->qtail = dmap->user_counter = 0;
	dmap->byte_counter = 0;
	reorganize_buffers(dev, adev->dmap_in, 1);
}

void DMAbuf_launch_output(int dev, struct dma_buffparms *dmap)
{
	struct audio_operations *adev = audio_devs[dev];

	if (!((adev->enable_bits * adev->go) & PCM_ENABLE_OUTPUT))
		return;		/* Don't start DMA yet */
	dmap->dma_mode = DMODE_OUTPUT;

	if (!(dmap->flags & DMA_ACTIVE) || !(adev->flags & DMA_AUTOMODE) || (dmap->flags & DMA_NODMA)) {
		if (!(dmap->flags & DMA_STARTED)) {
			reorganize_buffers(dev, dmap, 0);
			if (adev->d->prepare_for_output(dev, dmap->fragment_size, dmap->nbufs))
				return;
			if (!(dmap->flags & DMA_NODMA))
				local_start_dma(adev, dmap->raw_buf_phys, dmap->bytes_in_use,DMA_MODE_WRITE);
			dmap->flags |= DMA_STARTED;
		}
		if (dmap->counts[dmap->qhead] == 0)
			dmap->counts[dmap->qhead] = dmap->fragment_size;
		dmap->dma_mode = DMODE_OUTPUT;
		adev->d->output_block(dev, dmap->raw_buf_phys + dmap->qhead * dmap->fragment_size,
				      dmap->counts[dmap->qhead], 1);
		if (adev->d->trigger)
			adev->d->trigger(dev,adev->enable_bits * adev->go);
	}
	dmap->flags |= DMA_ACTIVE;
}

int DMAbuf_sync(int dev)
{
	struct audio_operations *adev = audio_devs[dev];
	unsigned long flags;
	int n = 0;
	struct dma_buffparms *dmap;

	if (!adev->go && !(adev->enable_bits & PCM_ENABLE_OUTPUT))
		return 0;

	if (adev->dmap_out->dma_mode == DMODE_OUTPUT) {