nm256_audio.c

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/* 
 * Audio driver for the NeoMagic 256AV and 256ZX chipsets in native
 * mode, with AC97 mixer support.
 *
 * Overall design and parts of this code stolen from vidc_*.c and
 * skeleton.c.
 *
 * Yeah, there are a lot of magic constants in here.  You tell ME what
 * they are.  I just get this stuff psychically, remember? 
 *
 * This driver was written by someone who wishes to remain anonymous. 
 * It is in the public domain, so share and enjoy.  Try to make a profit
 * off of it; go on, I dare you.  
 *
 * Changes:
 * 11-10-2000	Bartlomiej Zolnierkiewicz <[e-mail]>
 *		Added some __init
 * 19-04-2001	Marcus Meissner <[e-mail]>
 *		Ported to 2.4 PCI API.
 */

#define __NO_VERSION__
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/delay.h>
#include "sound_config.h"
#include "nm256.h"
#include "nm256_coeff.h"

int nm256_debug;
static int force_load;

/* 
 * The size of the playback reserve.  When the playback buffer has less
 * than NM256_PLAY_WMARK_SIZE bytes to output, we request a new
 * buffer.
 */
#define NM256_PLAY_WMARK_SIZE 512

static struct audio_driver nm256_audio_driver;

static int nm256_grabInterrupt (struct nm256_info *card);
static int nm256_releaseInterrupt (struct nm256_info *card);
static void nm256_interrupt (int irq, void *dev_id, struct pt_regs *dummy);
static void nm256_interrupt_zx (int irq, void *dev_id, struct pt_regs *dummy);
static int handle_pm_event (struct pm_dev *dev, pm_request_t rqst, void *data);

/* These belong in linux/pci.h. */
#define PCI_DEVICE_ID_NEOMAGIC_NM256AV_AUDIO 0x8005
#define PCI_DEVICE_ID_NEOMAGIC_NM256ZX_AUDIO 0x8006

/* List of cards.  */
static struct nm256_info *nmcard_list;

/* Release the mapped-in memory for CARD.  */
static void
nm256_release_ports (struct nm256_info *card)
{
    int x;

    for (x = 0; x < 2; x++) {
	if (card->port[x].ptr != NULL) {
	    iounmap (card->port[x].ptr);
	    card->port[x].ptr = NULL;
	}
    }
}

/* 
 * Map in the memory ports for CARD, if they aren't already mapped in
 * and have been configured.  If successful, a zero value is returned;
 * otherwise any previously mapped-in areas are released and a non-zero
 * value is returned.
 *
 * This is invoked twice, once for each port.  Ideally it would only be
 * called once, but we now need to map in the second port in order to
 * check how much memory the card has on the 256ZX.
 */
static int
nm256_remap_ports (struct nm256_info *card)
{
    int x;

    for (x = 0; x < 2; x++) {
	if (card->port[x].ptr == NULL && card->port[x].end_offset > 0) {
	    u32 physaddr 
		= card->port[x].physaddr + card->port[x].start_offset;
	    u32 size 
		= card->port[x].end_offset - card->port[x].start_offset;

	    card->port[x].ptr = ioremap_nocache (physaddr, size);
						  
	    if (card->port[x].ptr == NULL) {
		printk (KERN_ERR "NM256: Unable to remap port %d\n", x + 1);
		nm256_release_ports (card);
		return -1;
	    }
	}
    }
    return 0;
}

/* Locate the card in our list. */
static struct nm256_info *
nm256_find_card (int dev)
{
    struct nm256_info *card;

    for (card = nmcard_list; card != NULL; card = card->next_card)
	if (card->dev[0] == dev || card->dev[1] == dev)
	    return card;

    return NULL;
}

/*
 * Ditto, but find the card struct corresponding to the mixer device DEV 
 * instead. 
 */
static struct nm256_info *
nm256_find_card_for_mixer (int dev)
{
    struct nm256_info *card;

    for (card = nmcard_list; card != NULL; card = card->next_card)
	if (card->mixer_oss_dev == dev)
	    return card;

    return NULL;
}

static int usecache;
static int buffertop;

/* Check to see if we're using the bank of cached coefficients. */
int
nm256_cachedCoefficients (struct nm256_info *card)
{
    return usecache;
}

/* The actual rates supported by the card. */
static int samplerates[9] = {
    8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000, 99999999
};

/*
 * Set the card samplerate, word size and stereo mode to correspond to
 * the settings in the CARD struct for the specified device in DEV.
 * We keep two separate sets of information, one for each device; the
 * hardware is not actually configured until a read or write is
 * attempted.
 */

int
nm256_setInfo (int dev, struct nm256_info *card)
{
    int x;
    int w;
    int targetrate;

    if (card->dev[0] == dev)
	w = 0;
    else if (card->dev[1] == dev)
	w = 1;
    else
	return -ENODEV;

    targetrate = card->sinfo[w].samplerate;

    if ((card->sinfo[w].bits != 8 && card->sinfo[w].bits != 16)
	|| targetrate < samplerates[0]
	|| targetrate > samplerates[7])
	return -EINVAL;

    for (x = 0; x < 8; x++)
	if (targetrate < ((samplerates[x] + samplerates[x + 1]) / 2))
	    break;

    if (x < 8) {
	u8 ratebits = ((x << 4) & NM_RATE_MASK);
	if (card->sinfo[w].bits == 16)
	    ratebits |= NM_RATE_BITS_16;
	if (card->sinfo[w].stereo)
	    ratebits |= NM_RATE_STEREO;

	card->sinfo[w].samplerate = samplerates[x];


	if (card->dev_for_play == dev && card->playing) {
	    if (nm256_debug)
		printk (KERN_DEBUG "Setting play ratebits to 0x%x\n",
			ratebits);
	    nm256_loadCoefficient (card, 0, x);
	    nm256_writePort8 (card, 2,
			      NM_PLAYBACK_REG_OFFSET + NM_RATE_REG_OFFSET,
			      ratebits);
	}

	if (card->dev_for_record == dev && card->recording) {
	    if (nm256_debug)
		printk (KERN_DEBUG "Setting record ratebits to 0x%x\n",
			ratebits);
	    nm256_loadCoefficient (card, 1, x);
	    nm256_writePort8 (card, 2,
			      NM_RECORD_REG_OFFSET + NM_RATE_REG_OFFSET,
			      ratebits);
	}
	return 0;
    }
    else
	return -EINVAL;
}

/* Start the play process going. */
static void
startPlay (struct nm256_info *card)
{
    if (! card->playing) {
	card->playing = 1;
	if (nm256_grabInterrupt (card) == 0) {
	    nm256_setInfo (card->dev_for_play, card);

	    /* Enable playback engine and interrupts. */
	    nm256_writePort8 (card, 2, NM_PLAYBACK_ENABLE_REG,
			      NM_PLAYBACK_ENABLE_FLAG | NM_PLAYBACK_FREERUN);

	    /* Enable both channels. */
	    nm256_writePort16 (card, 2, NM_AUDIO_MUTE_REG, 0x0);
	}
    }
}

/* 
 * Request one chunk of AMT bytes from the recording device.  When the
 * operation is complete, the data will be copied into BUFFER and the
 * function DMAbuf_inputintr will be invoked.
 */

static void
nm256_startRecording (struct nm256_info *card, char *buffer, u32 amt)
{
    u32 endpos;
    int enableEngine = 0;
    u32 ringsize = card->recordBufferSize;
    unsigned long flags;

    if (amt > (ringsize / 2)) {
	/*
	 * Of course this won't actually work right, because the
	 * caller is going to assume we will give what we got asked
	 * for.
	 */
	printk (KERN_ERR "NM256: Read request too large: %d\n", amt);
	amt = ringsize / 2;
    }

    if (amt < 8) {
	printk (KERN_ERR "NM256: Read request too small; %d\n", amt);
	return;
    }

    save_flags (flags);
    cli ();
    /*
     * If we're not currently recording, set up the start and end registers
     * for the recording engine.
     */
    if (! card->recording) {
	card->recording = 1;
	if (nm256_grabInterrupt (card) == 0) {
	    card->curRecPos = 0;
	    nm256_setInfo (card->dev_for_record, card);
	    nm256_writePort32 (card, 2, NM_RBUFFER_START, card->abuf2);
	    nm256_writePort32 (card, 2, NM_RBUFFER_END,
				 card->abuf2 + ringsize);

	    nm256_writePort32 (card, 2, NM_RBUFFER_CURRP,
				 card->abuf2 + card->curRecPos);
	    enableEngine = 1;
	}
	else {
	    /* Not sure what else to do here.  */
	    restore_flags (flags);
	    return;
	}
    }

    /* 
     * If we happen to go past the end of the buffer a bit (due to a
     * delayed interrupt) it's OK.  So might as well set the watermark
     * right at the end of the data we want.
     */
    endpos = card->abuf2 + ((card->curRecPos + amt) % ringsize);

    card->recBuf = buffer;
    card->requestedRecAmt = amt;
    nm256_writePort32 (card, 2, NM_RBUFFER_WMARK, endpos);
    /* Enable recording engine and interrupts. */
    if (enableEngine)
	nm256_writePort8 (card, 2, NM_RECORD_ENABLE_REG,
			    NM_RECORD_ENABLE_FLAG | NM_RECORD_FREERUN);

    restore_flags (flags);
}

/* Stop the play engine. */
static void
stopPlay (struct nm256_info *card)
{
    /* Shut off sound from both channels. */
    nm256_writePort16 (card, 2, NM_AUDIO_MUTE_REG,
		       NM_AUDIO_MUTE_LEFT | NM_AUDIO_MUTE_RIGHT);
    /* Disable play engine. */
    nm256_writePort8 (card, 2, NM_PLAYBACK_ENABLE_REG, 0);
    if (card->playing) {
	nm256_releaseInterrupt (card);

	/* Reset the relevant state bits. */
	card->playing = 0;
	card->curPlayPos = 0;
    }
}

/* Stop recording. */
static void
stopRecord (struct nm256_info *card)
{
    /* Disable recording engine. */
    nm256_writePort8 (card, 2, NM_RECORD_ENABLE_REG, 0);

    if (card->recording) {
	nm256_releaseInterrupt (card);

	card->recording = 0;
	card->curRecPos = 0;
    }
}

/*
 * Ring buffers, man.  That's where the hip-hop, wild-n-wooly action's at.
 * 1972?  (Well, I suppose it was cheep-n-easy to implement.)
 *
 * Write AMT bytes of BUFFER to the playback ring buffer, and start the
 * playback engine running.  It will only accept up to 1/2 of the total
 * size of the ring buffer.  No check is made that we're about to overwrite
 * the currently-playing sample.
 */

static void
nm256_write_block (struct nm256_info *card, char *buffer, u32 amt)
{
    u32 ringsize = card->playbackBufferSize;
    u32 endstop;
    unsigned long flags;

    if (amt > (ringsize / 2)) {
	printk (KERN_ERR "NM256: Write request too large: %d\n", amt);
	amt = (ringsize / 2);
    }

    if (amt < NM256_PLAY_WMARK_SIZE) {
	printk (KERN_ERR "NM256: Write request too small: %d\n", amt);
	return;
    }

    card->curPlayPos %= ringsize;

    card->requested_amt = amt;

    save_flags (flags);
    cli ();

    if ((card->curPlayPos + amt) >= ringsize) {
	u32 rem = ringsize - card->curPlayPos;

	nm256_writeBuffer8 (card, buffer, 1,
			      card->abuf1 + card->curPlayPos,
			      rem);
	if (amt > rem)
	    nm256_writeBuffer8 (card, buffer + rem, 1, card->abuf1,
				  amt - rem);
    } 
    else
	nm256_writeBuffer8 (card, buffer, 1,
			      card->abuf1 + card->curPlayPos,
			      amt);

    /*
     * Setup the start-n-stop-n-limit registers, and start that engine
     * goin'. 
     *
     * Normally we just let it wrap around to avoid the click-click
     * action scene.
     */
    if (! card->playing) {
	/* The PBUFFER_END register in this case points to one sample
	   before the end of the buffer. */
	int w = (card->dev_for_play == card->dev[0] ? 0 : 1);
	int sampsize = (card->sinfo[w].bits == 16 ? 2 : 1);

	if (card->sinfo[w].stereo)
	    sampsize *= 2;

	/* Need to set the not-normally-changing-registers up. */
	nm256_writePort32 (card, 2, NM_PBUFFER_START,
			     card->abuf1 + card->curPlayPos);
	nm256_writePort32 (card, 2, NM_PBUFFER_END,
			     card->abuf1 + ringsize - sampsize);
	nm256_writePort32 (card, 2, NM_PBUFFER_CURRP,
			     card->abuf1 + card->curPlayPos);
    }
    endstop = (card->curPlayPos + amt - NM256_PLAY_WMARK_SIZE) % ringsize;
    nm256_writePort32 (card, 2, NM_PBUFFER_WMARK, card->abuf1 + endstop);

    if (! card->playing)
	startPlay (card);

    restore_flags (flags);
}

/*  We just got a card playback interrupt; process it.  */
static void
nm256_get_new_block (struct nm256_info *card)
{
    /* Check to see how much got played so far. */
    u32 amt = nm256_readPort32 (card, 2, NM_PBUFFER_CURRP) - card->abuf1;

    if (amt >= card->playbackBufferSize) {
	printk (KERN_ERR "NM256: Sound playback pointer invalid!\n");
	amt = 0;
    }

    if (amt < card->curPlayPos)
	amt = (card->playbackBufferSize - card->curPlayPos) + amt;
    else
	amt -= card->curPlayPos;

    if (card->requested_amt > (amt + NM256_PLAY_WMARK_SIZE)) {
	u32 endstop =
	    card->curPlayPos + card->requested_amt - NM256_PLAY_WMARK_SIZE;
	nm256_writePort32 (card, 2, NM_PBUFFER_WMARK, card->abuf1 + endstop);
    } 
    else {
	card->curPlayPos += card->requested_amt;
	/* Get a new block to write.  This will eventually invoke
	   nm256_write_block () or stopPlay ().  */
	DMAbuf_outputintr (card->dev_for_play, 1);
    }
}

/* Ultra cheez-whiz.  But I'm too lazy to grep headers. */
#define MIN(X,Y) ((X) < (Y) ? (X) : (Y))

/* 
 * Read the last-recorded block from the ring buffer, copy it into the
 * saved buffer pointer, and invoke DMAuf_inputintr() with the recording
 * device. 
 */

static void
nm256_read_block (struct nm256_info *card)
{
    /* Grab the current position of the recording pointer. */
    u32 currptr = nm256_readPort32 (card, 2, NM_RBUFFER_CURRP) - card->abuf2;
    u32 amtToRead = card->requestedRecAmt;
    u32 ringsize = card->recordBufferSize;

    if (currptr >= card->recordBufferSize) {
	printk (KERN_ERR "NM256: Sound buffer record pointer invalid!\n");
        currptr = 0;
    }

    /*
     * This test is probably redundant; we shouldn't be here unless
     * it's true.
     */
    if (card->recording) {
	/* If we wrapped around, copy everything from the start of our
	   recording buffer to the end of the buffer. */
	if (currptr < card->curRecPos) {
	    u32 amt = MIN (ringsize - card->curRecPos, amtToRead);

	    nm256_readBuffer8 (card, card->recBuf, 1,
				 card->abuf2 + card->curRecPos,
				 amt);
	    amtToRead -= amt;
	    card->curRecPos += amt;
	    card->recBuf += amt;
	    if (card->curRecPos == ringsize)
		card->curRecPos = 0;
	}

	if ((card->curRecPos < currptr) && (amtToRead > 0)) {
	    u32 amt = MIN (currptr - card->curRecPos, amtToRead);
	    nm256_readBuffer8 (card, card->recBuf, 1,
				 card->abuf2 + card->curRecPos, amt);
	    card->curRecPos = ((card->curRecPos + amt) % ringsize);
	}
	card->recBuf = NULL;
	card->requestedRecAmt = 0;
	DMAbuf_inputintr (card->dev_for_record);
    }
}
#undef MIN

/* 
 * Initialize the hardware. 
 */
static void
nm256_initHw (struct nm256_info *card)
{
    /* Reset everything. */
    nm256_writePort8 (card, 2, 0x0, 0x11);
    nm256_writePort16 (card, 2, 0x214, 0);

    stopRecord (card);
    stopPlay (card);
}

/* 
 * Handle a potential interrupt for the device referred to by DEV_ID. 
 *
 * I don't like the cut-n-paste job here either between the two routines,
 * but there are sufficient differences between the two interrupt handlers
 * that parameterizing it isn't all that great either.  (Could use a macro,
 * I suppose...yucky bleah.)
 */

static void
nm256_interrupt (int irq, void *dev_id, struct pt_regs *dummy)
{
    struct nm256_info *card = (struct nm256_info *)dev_id;
    u16 status;
    static int badintrcount = 0;

    if ((card == NULL) || (card->magsig != NM_MAGIC_SIG)) {
	printk (KERN_ERR "NM256: Bad card pointer\n");
	return;
    }

    status = nm256_readPort16 (card, 2, NM_INT_REG);

    /* Not ours. */
    if (status == 0) {
	if (badintrcount++ > 1000) {
	    /*
	     * I'm not sure if the best thing is to stop the card from
	     * playing or just release the interrupt (after all, we're in
	     * a bad situation, so doing fancy stuff may not be such a good
	     * idea).
	     *
	     * I worry about the card engine continuing to play noise
	     * over and over, however--that could become a very
	     * obnoxious problem.  And we know that when this usually
	     * happens things are fairly safe, it just means the user's
	     * inserted a PCMCIA card and someone's spamming us with IRQ 9s.
	     */

	    if (card->playing)
		stopPlay (card);
	    if (card->recording)