cmpci.c

讲述linux的初始化过程

	unsigned char	freq;
} rate_lookup[] =
{
	{ 5512,		(0 + 5512) / 2,		(5512 + 8000) / 2,	0 },
	{ 8000,		(5512 + 8000) / 2,	(8000 + 11025) / 2,	4 },
	{ 11025,	(8000 + 11025) / 2,	(11025 + 16000) / 2,	1 },
	{ 16000,	(11025 + 16000) / 2,	(16000 + 22050) / 2,	5 },
	{ 22050,	(16000 + 22050) / 2,	(22050 + 32000) / 2,	2 },
	{ 32000,	(22050 + 32000) / 2,	(32000 + 44100) / 2,	6 },
	{ 44100,	(32000 + 44100) / 2,	(44100 + 48000) / 2,	3 },
	{ 48000,	(44100 + 48000) /2,	48000,			7 }
};

static void set_dac_rate(struct cm_state *s, unsigned rate)
{
	unsigned long flags;
	unsigned char freq = 4, val;
	int	i;

	if (rate > 48000)
		rate = 48000;
	if (rate < 5512)
		rate = 5512;
	for (i = 0; i < sizeof(rate_lookup) / sizeof(rate_lookup[0]); i++)
	{
		if (rate > rate_lookup[i].lower && rate <= rate_lookup[i].upper)
		{
			rate = rate_lookup[i].rate;
			freq = rate_lookup[i].freq;
			break;
	    	}
	}
	s->ratedac = rate;
	freq <<= 2;
	spin_lock_irqsave(&s->lock, flags);
	val = inb(s->iobase + CODEC_CMI_FUNCTRL1 + 1) & ~0x1c; 
	outb(val | freq, s->iobase + CODEC_CMI_FUNCTRL1 + 1);
	spin_unlock_irqrestore(&s->lock, flags);
}

static void set_adc_rate(struct cm_state *s, unsigned rate)
{
	unsigned long flags;
	unsigned char freq = 4, val;
	int	i;

	if (rate > 48000)
		rate = 48000;
	if (rate < 5512)
		rate = 5512;
	for (i = 0; i < sizeof(rate_lookup) / sizeof(rate_lookup[0]); i++)
	{
		if (rate > rate_lookup[i].lower && rate <= rate_lookup[i].upper)
		{
			rate = rate_lookup[i].rate;
			freq = rate_lookup[i].freq;
			break;
	    	}
	}
	s->rateadc = rate;
	freq <<= 5;
	spin_lock_irqsave(&s->lock, flags);
	val = inb(s->iobase + CODEC_CMI_FUNCTRL1 + 1) & ~0xe0; 
	outb(val | freq, s->iobase + CODEC_CMI_FUNCTRL1 + 1);
	spin_unlock_irqrestore(&s->lock, flags);
}

/* --------------------------------------------------------------------- */

extern inline void stop_adc(struct cm_state *s)
{
	unsigned long flags;

	spin_lock_irqsave(&s->lock, flags);
	/* disable channel */
	outb(s->enable, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
	s->enable &= ~CM_CENABLE_RE;
	/* disable interrupt */
	outb(inb(s->iobase + CODEC_CMI_INT_HLDCLR + 2) & ~2, s->iobase + CODEC_CMI_INT_HLDCLR + 2);
	/* reset */
	outb(s->enable | CM_CH1_RESET, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
	udelay(10);
	outb(s->enable & ~CM_CH1_RESET, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
	spin_unlock_irqrestore(&s->lock, flags);
}	

extern inline void stop_dac(struct cm_state *s)
{
	unsigned long flags;

	spin_lock_irqsave(&s->lock, flags);
	/* disable channel */
	s->enable &= ~CM_CENABLE_PE;
	outb(s->enable, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
	/* disable interrupt */
	outb(inb(s->iobase + CODEC_CMI_INT_HLDCLR + 2) & ~1, s->iobase + CODEC_CMI_INT_HLDCLR + 2);
	/* reset */
	outb(s->enable | CM_CH0_RESET, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
	udelay(10);
	outb(s->enable & ~CM_CH0_RESET, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
	spin_unlock_irqrestore(&s->lock, flags);
}	

static void start_dac(struct cm_state *s)
{
	unsigned long flags;

	spin_lock_irqsave(&s->lock, flags);
	if ((s->dma_dac.mapped || s->dma_dac.count > 0) && s->dma_dac.ready) {
		outb(inb(s->iobase + CODEC_CMI_INT_HLDCLR + 2) | 1, s->iobase + CODEC_CMI_INT_HLDCLR + 2);
		s->enable |= CM_CENABLE_PE;
		outb(s->enable, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
	}
	spin_unlock_irqrestore(&s->lock, flags);
}	

static void start_adc(struct cm_state *s)
{
	unsigned long flags;

	spin_lock_irqsave(&s->lock, flags);
	if ((s->dma_adc.mapped || s->dma_adc.count < (signed)(s->dma_adc.dmasize - 2*s->dma_adc.fragsize)) 
	    && s->dma_adc.ready) {
		outb(inb(s->iobase + CODEC_CMI_INT_HLDCLR + 2) | 2, s->iobase + CODEC_CMI_INT_HLDCLR + 2);
		s->enable |= CM_CENABLE_RE;
		outb(s->enable, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
	}
	spin_unlock_irqrestore(&s->lock, flags);
}	

/* --------------------------------------------------------------------- */

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

static void dealloc_dmabuf(struct dmabuf *db)
{
	struct page *pstart, *pend;

	if (db->rawbuf) {
		/* undo marking the pages as reserved */
		pend = virt_to_page(db->rawbuf + (PAGE_SIZE << db->buforder) - 1);
		for (pstart = virt_to_page(db->rawbuf); pstart <= pend; pstart++)
			mem_map_unreserve(pstart);
		free_pages((unsigned long)db->rawbuf, db->buforder);
	}
	db->rawbuf = NULL;
	db->mapped = db->ready = 0;
}


/* Ch0 is used for playback, Ch1 is used for recording */

static int prog_dmabuf(struct cm_state *s, unsigned rec)
{
	struct dmabuf *db = rec ? &s->dma_adc : &s->dma_dac;
	unsigned rate = rec ? s->rateadc : s->ratedac;
	int order;
	unsigned bytepersec;
	unsigned bufs;
	struct page *pstart, *pend;
	unsigned char fmt;
	unsigned long flags;

	spin_lock_irqsave(&s->lock, flags);
	fmt = s->fmt;
	if (rec) {
		s->enable &= ~CM_CENABLE_RE;
		fmt >>= CM_CFMT_ADCSHIFT;
	} else {
		s->enable &= ~CM_CENABLE_PE;
		fmt >>= CM_CFMT_DACSHIFT;
	}
	outb(s->enable, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
	spin_unlock_irqrestore(&s->lock, flags);
	fmt &= CM_CFMT_MASK;
	db->hwptr = db->swptr = db->total_bytes = db->count = db->error = db->endcleared = 0;
	if (!db->rawbuf) {
		db->ready = db->mapped = 0;
		for (order = DMABUF_DEFAULTORDER; order >= DMABUF_MINORDER; order--)
			if ((db->rawbuf = (void *)__get_free_pages(GFP_KERNEL | GFP_DMA, order)))
				break;
		if (!db->rawbuf)
			return -ENOMEM;
		db->buforder = order;
		if ((virt_to_bus(db->rawbuf) ^ (virt_to_bus(db->rawbuf) + (PAGE_SIZE << db->buforder) - 1)) & ~0xffff)
			printk(KERN_DEBUG "cmpci: DMA buffer crosses 64k boundary: busaddr 0x%lx  size %ld\n", 
			       virt_to_bus(db->rawbuf), PAGE_SIZE << db->buforder);
		if ((virt_to_bus(db->rawbuf) + (PAGE_SIZE << db->buforder) - 1) & ~0xffffff)
			printk(KERN_DEBUG "cmpci: DMA buffer beyond 16MB: busaddr 0x%lx  size %ld\n", 
			       virt_to_bus(db->rawbuf), PAGE_SIZE << db->buforder);
		/* now mark the pages as reserved; otherwise remap_page_range doesn't do what we want */
		pend = virt_to_page(db->rawbuf + (PAGE_SIZE << db->buforder) - 1);
		for (pstart = virt_to_page(db->rawbuf); pstart <= pend; pstart++)
			mem_map_reserve(pstart);
	}
	bytepersec = rate << sample_shift[fmt];
	bufs = PAGE_SIZE << db->buforder;
	if (db->ossfragshift) {
		if ((1000 << db->ossfragshift) < bytepersec)
			db->fragshift = ld2(bytepersec/1000);
		else
			db->fragshift = db->ossfragshift;
	} else {
		db->fragshift = ld2(bytepersec/100/(db->subdivision ? db->subdivision : 1));
		if (db->fragshift < 3)
			db->fragshift = 3;
	}
	db->numfrag = bufs >> db->fragshift;
	while (db->numfrag < 4 && db->fragshift > 3) {
		db->fragshift--;
		db->numfrag = bufs >> db->fragshift;
	}
	db->fragsize = 1 << db->fragshift;
	if (db->ossmaxfrags >= 4 && db->ossmaxfrags < db->numfrag)
		db->numfrag = db->ossmaxfrags;
 	/* to make fragsize >= 4096 */
#if 0 	
 	if(s->modem)
 	{
	 	while (db->fragsize < 4096 && db->numfrag >= 4)
		{
			db->fragsize *= 2;
 			db->fragshift++;
 			db->numfrag /= 2;
 		}
	}
#endif	
	db->fragsamples = db->fragsize >> sample_shift[fmt];
	db->dmasize = db->numfrag << db->fragshift;
	db->dmasamples = db->dmasize >> sample_shift[fmt];
	memset(db->rawbuf, (fmt & CM_CFMT_16BIT) ? 0 : 0x80, db->dmasize);
	spin_lock_irqsave(&s->lock, flags);
	if (rec) {
		set_dmaadc(s, virt_to_bus(db->rawbuf), db->dmasize >> sample_shift[fmt]);
		/* program sample counts */
		outw(db->fragsamples-1, s->iobase + CODEC_CMI_CH1_FRAME2 + 2);
	} else {
		set_dmadac(s, virt_to_bus(db->rawbuf), db->dmasize >> sample_shift[fmt]);
		/* program sample counts */
		outw(db->fragsamples-1, s->iobase + CODEC_CMI_CH0_FRAME2 + 2);
	}
	spin_unlock_irqrestore(&s->lock, flags);
	db->ready = 1;
	return 0;
}

extern __inline__ void clear_advance(struct cm_state *s)
{
	unsigned char c = (s->fmt & (CM_CFMT_16BIT << CM_CFMT_DACSHIFT)) ? 0 : 0x80;
	unsigned char *buf = s->dma_dac.rawbuf;
	unsigned bsize = s->dma_dac.dmasize;
	unsigned bptr = s->dma_dac.swptr;
	unsigned len = s->dma_dac.fragsize;

	if (bptr + len > bsize) {
		unsigned x = bsize - bptr;
		memset(buf + bptr, c, x);
		bptr = 0;
		len -= x;
	}
	memset(buf + bptr, c, len);
	outb(s->enable, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
}

/* call with spinlock held! */
static void cm_update_ptr(struct cm_state *s)
{
	unsigned hwptr;
	int diff;

	/* update ADC pointer */
	if (s->dma_adc.ready) {
		hwptr = (s->dma_adc.dmasize - get_dmaadc(s)) % s->dma_adc.dmasize;
		diff = (s->dma_adc.dmasize + hwptr - s->dma_adc.hwptr) % s->dma_adc.dmasize;
		s->dma_adc.hwptr = hwptr;
		s->dma_adc.total_bytes += diff;
		s->dma_adc.count += diff;
		if (s->dma_adc.count >= (signed)s->dma_adc.fragsize) 
			wake_up(&s->dma_adc.wait);
		if (!s->dma_adc.mapped) {
			if (s->dma_adc.count > (signed)(s->dma_adc.dmasize - ((3 * s->dma_adc.fragsize) >> 1))) {
				s->enable &= ~CM_CENABLE_RE;
				outb(s->enable, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
				s->dma_adc.error++;
			}
		}
	}
	/* update DAC pointer */
	if (s->dma_dac.ready) {
		hwptr = (s->dma_dac.dmasize - get_dmadac(s)) % s->dma_dac.dmasize;
		diff = (s->dma_dac.dmasize + hwptr - s->dma_dac.hwptr) % s->dma_dac.dmasize;
		s->dma_dac.hwptr = hwptr;
		s->dma_dac.total_bytes += diff;
		if (s->dma_dac.mapped) {
			s->dma_dac.count += diff;
			if (s->dma_dac.count >= (signed)s->dma_dac.fragsize)
				wake_up(&s->dma_dac.wait);
		} else {
			s->dma_dac.count -= diff;
			if (s->dma_dac.count <= 0) {
				s->enable &= ~CM_CENABLE_PE;
				outb(s->enable, s->iobase + CODEC_CMI_FUNCTRL0 + 2);
				s->dma_dac.error++;
			} else if (s->dma_dac.count <= (signed)s->dma_dac.fragsize && !s->dma_dac.endcleared) {
				clear_advance(s);
				s->dma_dac.endcleared = 1;
			}
			if (s->dma_dac.count + (signed)s->dma_dac.fragsize <= (signed)s->dma_dac.dmasize)
				wake_up(&s->dma_dac.wait);
		}
	}
}

/* hold spinlock for the following! */
static void cm_handle_midi(struct cm_state *s)
{
	unsigned char ch;
	int wake;

	wake = 0;
	while (!(inb(s->iomidi+1) & 0x80)) {
		ch = inb(s->iomidi);
		if (s->midi.icnt < MIDIINBUF) {
			s->midi.ibuf[s->midi.iwr] = ch;
			s->midi.iwr = (s->midi.iwr + 1) % MIDIINBUF;
			s->midi.icnt++;
		}
		wake = 1;
	}
	if (wake)
		wake_up(&s->midi.iwait);
	wake = 0;
	while (!(inb(s->iomidi+1) & 0x40) && s->midi.ocnt > 0) {
		outb(s->midi.obuf[s->midi.ord], s->iomidi);
		s->midi.ord = (s->midi.ord + 1) % MIDIOUTBUF;
		s->midi.ocnt--;
		if (s->midi.ocnt < MIDIOUTBUF-16)
			wake = 1;
	}
	if (wake)
		wake_up(&s->midi.owait);
}

static void cm_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
        struct cm_state *s = (struct cm_state *)dev_id;
	unsigned int intsrc, intstat;
	
	/* fastpath out, to ease interrupt sharing */
	intsrc = inl(s->iobase + CODEC_CMI_INT_STATUS);
	if (!(intsrc & 0x80000000))
		return;
	spin_lock(&s->lock);
	intstat = inb(s->iobase + CODEC_CMI_INT_HLDCLR + 2);
	/* acknowledge interrupt */
	if (intsrc & CM_INT_CH0)
	{
		outb(intstat & ~1, s->iobase + CODEC_CMI_INT_HLDCLR + 2);
		udelay(10);
		outb(intstat | 1, s->iobase + CODEC_CMI_INT_HLDCLR + 2);
	}
	if (intsrc & CM_INT_CH1)
	{
		outb(intstat & ~2, s->iobase + CODEC_CMI_INT_HLDCLR + 2);
		udelay(10);
		outb(intstat | 2, s->iobase + CODEC_CMI_INT_HLDCLR + 2);
	}
	cm_update_ptr(s);
	cm_handle_midi(s);
	spin_unlock(&s->lock);
}

static void cm_midi_timer(unsigned long data)
{
	struct cm_state *s = (struct cm_state *)data;
	unsigned long flags;
	
	spin_lock_irqsave(&s->lock, flags);
	cm_handle_midi(s);
	spin_unlock_irqrestore(&s->lock, flags);
	s->midi.timer.expires = jiffies+1;
	add_timer(&s->midi.timer);
}

/* --------------------------------------------------------------------- */

static const char invalid_magic[] = KERN_CRIT "cmpci: invalid magic value\n";

#ifdef CONFIG_SOUND_CMPCI	/* support multiple chips */
#define VALIDATE_STATE(s)
#else
#define VALIDATE_STATE(s)                         \
({                                                \
	if (!(s) || (s)->magic != CM_MAGIC) { \
		printk(invalid_magic);            \
		return -ENXIO;                    \
	}                                         \
})
#endif

/* --------------------------------------------------------------------- */

#define MT_4          1
#define MT_5MUTE      2
#define MT_4MUTEMONO  3
#define MT_6MUTE      4
#define MT_5MUTEMONO  5

static const struct {
	unsigned left;
	unsigned right;
	unsigned type;
	unsigned rec;
	unsigned play;
} mixtable[SOUND_MIXER_NRDEVICES] = {
	[SOUND_MIXER_CD]     = { DSP_MIX_CDVOLIDX_L,     DSP_MIX_CDVOLIDX_R,     MT_5MUTE,     0x04, 0x02 },
	[SOUND_MIXER_LINE]   = { DSP_MIX_LINEVOLIDX_L,   DSP_MIX_LINEVOLIDX_R,   MT_5MUTE,     0x10, 0x08 },
	[SOUND_MIXER_MIC]    = { DSP_MIX_MICVOLIDX,      DSP_MIX_MICVOLIDX,      MT_5MUTEMONO, 0x01, 0x01 },
	[SOUND_MIXER_SYNTH]  = { DSP_MIX_FMVOLIDX_L,  	 DSP_MIX_FMVOLIDX_R,     MT_5MUTE,     0x40, 0x00 },
	[SOUND_MIXER_VOLUME] = { DSP_MIX_MASTERVOLIDX_L, DSP_MIX_MASTERVOLIDX_R, MT_5MUTE,     0x00, 0x00 },
	[SOUND_MIXER_PCM]    = { DSP_MIX_VOICEVOLIDX_L,  DSP_MIX_VOICEVOLIDX_R,  MT_5MUTE,     0x00, 0x00 }
};

#ifdef OSS_DOCUMENTED_MIXER_SEMANTICS

static int return_mixval(struct cm_state *s, unsigned i, int *arg)
{
	unsigned long flags;
	unsigned char l, r, rl, rr;

	spin_lock_irqsave(&s->lock, flags);
	l = rdmixer(s, mixtable[i].left);
	r = rdmixer(s, mixtable[i].right);
	spin_unlock_irqrestore(&s->lock, flags);
	switch (mixtable[i].type) {
	case MT_4:
		r &= 0xf;
		l &= 0xf;
		rl = 10 + 6 * (l & 15);
		rr = 10 + 6 * (r & 15);
		break;

	case MT_4MUTEMONO:
		rl = 55 - 3 * (l & 15);
		if (r & 0x10)
			rl += 45;
		rr = rl;
		r = l;
		break;

	case MT_5MUTEMONO:
		r = l;
		rl = 100 - 3 * ((l >> 3) & 31);
		rr = rl;