aci.c

讲述linux的初始化过程

 * following nice properties:
 *
 * - SCALE(xmax,ymax,xmax) = ymax
 * - SCALE(xmax,ymax,0) = 0
 * - SCALE(xmax,ymax,SCALE(ymax,xmax,SCALE(xmax,ymax,x))) = SCALE(xmax,ymax,x)
 *
 * In addition, the rounding error is minimal and nicely distributed.
 * The proofs are left as an exercise to the reader.
 */

#define SCALE(xmax,ymax,x) (((x)*(ymax)+(xmax)/2)/(xmax))


static int getvolume(caddr_t arg,
		     unsigned char left_index, unsigned char right_index)
{
	int vol;
	unsigned char buf;

	/* left channel */
	if (aci_indexed_cmd(0xf0, left_index, &buf))
		return -EIO;
	vol = SCALE(0x20, 100, buf < 0x20 ? 0x20-buf : 0);
	
	/* right channel */
	if (aci_indexed_cmd(0xf0, right_index, &buf))
		return -EIO;
	vol |= SCALE(0x20, 100, buf < 0x20 ? 0x20-buf : 0) << 8;

	return (*(int *) arg = vol);
}


static int setvolume(caddr_t arg, 
		     unsigned char left_index, unsigned char right_index)
{
	int vol, ret;

	/* left channel */
	vol = *(int *)arg & 0xff;
	if (vol > 100)
		vol = 100;
	vol = SCALE(100, 0x20, vol);
	if (aci_write_cmd(left_index, 0x20 - vol))
		return -EIO;
	ret = SCALE(0x20, 100, vol);


	/* right channel */
	vol = (*(int *)arg >> 8) & 0xff;
	if (vol > 100)
		vol = 100;
	vol = SCALE(100, 0x20, vol);
	if (aci_write_cmd(right_index, 0x20 - vol))
		return -EIO;
	ret |= SCALE(0x20, 100, vol) << 8;
 
	return (*(int *) arg = ret);
}


static int
aci_mixer_ioctl (int dev, unsigned int cmd, caddr_t arg)
{
	int status, vol;
	unsigned char buf;

	/* handle solo mode control */
	if (cmd == SOUND_MIXER_PRIVATE1) {
		if (*(int *) arg >= 0) {
			aci_solo = !!*(int *) arg;
			if (aci_write_cmd(0xd2, aci_solo))
				return -EIO;
		} else if (aci_version >= 0xb0) {
			if ((status = read_general_status()) < 0)
				return -EIO;
			return (*(int *) arg = (status & 0x20) == 0);
		}
		
		return (*(int *) arg = aci_solo);
	}
	
	if (((cmd >> 8) & 0xff) == 'M') {
		if (cmd & SIOC_IN)
			/* read and write */
			switch (cmd & 0xff) {
				case SOUND_MIXER_VOLUME:
					return setvolume(arg, 0x01, 0x00);
				case SOUND_MIXER_CD:
					return setvolume(arg, 0x3c, 0x34);
				case SOUND_MIXER_MIC:
					return setvolume(arg, 0x38, 0x30);
				case SOUND_MIXER_LINE:
					return setvolume(arg, 0x39, 0x31);
				case SOUND_MIXER_SYNTH:
					return setvolume(arg, 0x3b, 0x33);
				case SOUND_MIXER_PCM:
					return setvolume(arg, 0x3a, 0x32);
				case SOUND_MIXER_LINE1:  /* AUX1 */
					return setvolume(arg, 0x3d, 0x35);
				case SOUND_MIXER_LINE2:  /* AUX2 */
					return setvolume(arg, 0x3e, 0x36);
				case SOUND_MIXER_IGAIN:  /* MIC pre-amp */
					vol = *(int *) arg & 0xff;
					if (vol > 100)
						vol = 100;
					vol = SCALE(100, 3, vol);
					if (aci_write_cmd(0x03, vol))
						return -EIO;
					vol = SCALE(3, 100, vol);
					return (*(int *) arg = vol | (vol << 8));
				case SOUND_MIXER_RECSRC:
					return (*(int *) arg = 0);
					break;
				default:
					return -EINVAL;
			}
		else
			/* only read */
			switch (cmd & 0xff) {
				case SOUND_MIXER_DEVMASK:
					return (*(int *) arg =
				 SOUND_MASK_VOLUME | SOUND_MASK_CD    |
				 SOUND_MASK_MIC    | SOUND_MASK_LINE  |
				 SOUND_MASK_SYNTH  | SOUND_MASK_PCM   |
#if 0
				 SOUND_MASK_IGAIN  |
#endif
				 SOUND_MASK_LINE1  | SOUND_MASK_LINE2);
				 	break;
				case SOUND_MIXER_STEREODEVS:
					return (*(int *) arg =
				 SOUND_MASK_VOLUME | SOUND_MASK_CD   |
				 SOUND_MASK_MIC    | SOUND_MASK_LINE |
				 SOUND_MASK_SYNTH  | SOUND_MASK_PCM  |
				 SOUND_MASK_LINE1  | SOUND_MASK_LINE2);
				 	break;
				case SOUND_MIXER_RECMASK:
					return (*(int *) arg = 0);
					break;
				case SOUND_MIXER_RECSRC:
					return (*(int *) arg = 0);
					break;
				case SOUND_MIXER_CAPS:
					return (*(int *) arg = 0);
					break;
				case SOUND_MIXER_VOLUME:
					return getvolume(arg, 0x04, 0x03);
				case SOUND_MIXER_CD:
					return getvolume(arg, 0x0a, 0x09);
				case SOUND_MIXER_MIC:
					return getvolume(arg, 0x06, 0x05);
				case SOUND_MIXER_LINE:
					return getvolume(arg, 0x08, 0x07);
				case SOUND_MIXER_SYNTH:
					return getvolume(arg, 0x0c, 0x0b);
				case SOUND_MIXER_PCM:
					return getvolume(arg, 0x0e, 0x0d);
				case SOUND_MIXER_LINE1:  /* AUX1 */
					return getvolume(arg, 0x11, 0x10);
				case SOUND_MIXER_LINE2:  /* AUX2 */
					return getvolume(arg, 0x13, 0x12);
				case SOUND_MIXER_IGAIN:  /* MIC pre-amp */
					if (aci_indexed_cmd(0xf0, 0x21, &buf))
						return -EIO;
					vol = SCALE(3, 100, buf <= 3 ? buf : 3);
					vol |= vol << 8;
					return (*(int *) arg = vol);
				default:
					return -EINVAL;
			}
	}
	
	return -EINVAL;
}


static struct mixer_operations aci_mixer_operations =
{
	owner:	THIS_MODULE,
	id:	"ACI",
	name:	"ACI mixer",
	ioctl:	aci_mixer_ioctl
};

static unsigned char
mad_read (int port)
{
	outb (0xE3, 0xf8f); /* Write MAD16 password */
	return inb (port);  /* Read from port */
}


/*
 * Check, whether there actually is any ACI port operational and if
 * one was found, then initialize the ACI interface, reserve the I/O
 * addresses and attach the new mixer to the relevant VoxWare data
 * structures.
 *
 * Returns:  1   ACI mixer detected
 *           0   nothing there
 *
 * There is also an internal mixer in the codec (CS4231A or AD1845),
 * that deserves no purpose in an ACI based system which uses an
 * external ACI controlled stereo mixer. Make sure that this codec
 * mixer has the AUX1 input selected as the recording source, that the
 * input gain is set near maximum and that the other channels going
 * from the inputs to the codec output are muted.
 */

static int __init attach_aci(void)
{
	char *boardname = "unknown";
	int volume;

#define MC4_PORT	0xf90

	aci_port =
		(mad_read(MC4_PORT) & 0x10) ? 0x344 : 0x354;

	if (check_region(aci_port, 3)) {
#ifdef DEBUG
		printk("ACI: I/O area 0x%03x-0x%03x already used.\n",
			aci_port, aci_port+2);
#endif
		return 0;
	}
	
	if (aci_read_cmd(0xf2, 2, aci_idcode)) {
#ifdef DEBUG
		printk("ACI: Failed to read idcode.\n");
#endif
		return 0;
	}
	
	if (aci_read_cmd(0xf1, 1, &aci_version)) {
#ifdef DEBUG
		printk("ACI: Failed to read version.\n");
#endif
		return 0;
	}

	if (aci_idcode[0] == 0x6d) {
		/* It looks like a miro sound card. */
		switch (aci_idcode[1]) {
			case 0x41:
				boardname = "PCM1 pro / early PCM12";
				break;
			case 0x42:
				boardname = "PCM12";
				break;
			case 0x43:
				boardname = "PCM20";
				break;
			default:
				boardname = "unknown miro";
		}
	} else
#ifndef DEBUG
	return 0;
#endif
  
  	printk("<ACI %02x, id %02x %02x (%s)> at 0x%03x\n",
		aci_version, aci_idcode[0], aci_idcode[1], boardname, aci_port);

	if (aci_reset) {
		/* initialize ACI mixer */
		aci_implied_cmd(0xff);
		aci_solo = 0;
	}

	/* attach the mixer */
	request_region(aci_port, 3, "sound mixer (ACI)");
	if (num_mixers < MAX_MIXER_DEV) {
		if (num_mixers > 0 &&
		  !strncmp("MAD16 WSS", mixer_devs[num_mixers-1]->name, 9)) {
			/*
			 * The previously registered mixer device is the CS4231A which
			 * has no function on an ACI card. Make the ACI mixer the first
			 * of the two mixer devices.
			 */
			mixer_devs[num_mixers] = mixer_devs[num_mixers-1];
			mixer_devs[num_mixers-1] = &aci_mixer_operations;
			/*
			 * Initialize the CS4231A mixer with reasonable values. It is
			 * unlikely that the user ever will want to change these as all
			 * channels can be mixed via ACI.
			 */
			volume = 0x6464;
			mixer_devs[num_mixers]->ioctl(num_mixers,
				SOUND_MIXER_WRITE_PCM, (caddr_t) &volume);
			volume = 0x6464;
			mixer_devs[num_mixers]->ioctl(num_mixers,
				SOUND_MIXER_WRITE_IGAIN,   (caddr_t) &volume);
			volume = 0;
			mixer_devs[num_mixers]->ioctl(num_mixers,
				SOUND_MIXER_WRITE_SPEAKER, (caddr_t) &volume);
			volume = 0;
			mixer_devs[num_mixers]->ioctl(num_mixers,
				SOUND_MIXER_WRITE_MIC, (caddr_t) &volume);
			volume = 0;
			mixer_devs[num_mixers]->ioctl(num_mixers,
				SOUND_MIXER_WRITE_IMIX, (caddr_t) &volume);
			volume = 0;
			mixer_devs[num_mixers]->ioctl(num_mixers,
				SOUND_MIXER_WRITE_LINE1, (caddr_t) &volume);
			volume = 0;
			mixer_devs[num_mixers]->ioctl(num_mixers,
				SOUND_MIXER_WRITE_LINE2, (caddr_t) &volume);
			volume = 0;
			mixer_devs[num_mixers]->ioctl(num_mixers,
				SOUND_MIXER_WRITE_LINE3, (caddr_t) &volume);
			volume = SOUND_MASK_LINE1;
			mixer_devs[num_mixers]->ioctl(num_mixers,
				SOUND_MIXER_WRITE_RECSRC, (caddr_t) &volume);
			num_mixers++;
		} else
			mixer_devs[num_mixers++] = &aci_mixer_operations;
	}

	/* Just do something; otherwise the first write command fails, at
	 * least with my PCM20.
	 */
	aci_mixer_ioctl(num_mixers-1, SOUND_MIXER_READ_VOLUME, (caddr_t) &volume);
	
	if (aci_reset) {
		/* Initialize ACI mixer with reasonable power-up values */
		volume = 0x3232;
		aci_mixer_ioctl(num_mixers-1, SOUND_MIXER_WRITE_VOLUME, (caddr_t) &volume);
		volume = 0x3232;
		aci_mixer_ioctl(num_mixers-1, SOUND_MIXER_WRITE_SYNTH,  (caddr_t) &volume);
		volume = 0x3232;
		aci_mixer_ioctl(num_mixers-1, SOUND_MIXER_WRITE_PCM,    (caddr_t) &volume);
		volume = 0x3232;
		aci_mixer_ioctl(num_mixers-1, SOUND_MIXER_WRITE_LINE,   (caddr_t) &volume);
		volume = 0x3232;
		aci_mixer_ioctl(num_mixers-1, SOUND_MIXER_WRITE_MIC,    (caddr_t) &volume);
		volume = 0x3232;
		aci_mixer_ioctl(num_mixers-1, SOUND_MIXER_WRITE_CD,     (caddr_t) &volume);
		volume = 0x3232;
		aci_mixer_ioctl(num_mixers-1, SOUND_MIXER_WRITE_LINE1,  (caddr_t) &volume);
		volume = 0x3232;
		aci_mixer_ioctl(num_mixers-1, SOUND_MIXER_WRITE_LINE2,  (caddr_t) &volume);
	}

	aci_present = 1;

	return 1;
}

static void __exit unload_aci(void)
{
	if (aci_present)
		release_region(aci_port, 3);
}

module_init(attach_aci);
module_exit(unload_aci);