On Tue, Nov 06, 2007 at 02:33:53AM -0800, akpm@linux-foundation.org wrote:

[mmotm.git] / sound / aoa / soundbus / i2sbus / pcm.c

/*
 * i2sbus driver -- pcm routines
 *
 * Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
 *
 * GPL v2, can be found in COPYING.
 */

#include <asm/io.h>
#include <linux/delay.h>
#include <sound/core.h>
#include <asm/macio.h>
#include <linux/pci.h>
#include "../soundbus.h"
#include "i2sbus.h"

static inline void get_pcm_info(struct i2sbus_dev *i2sdev, int in,
                                struct pcm_info **pi, struct pcm_info **other)
{
        if (in) {
                if (pi)
                        *pi = &i2sdev->in;
                if (other)
                        *other = &i2sdev->out;
        } else {
                if (pi)
                        *pi = &i2sdev->out;
                if (other)
                        *other = &i2sdev->in;
        }
}

static int clock_and_divisors(int mclk, int sclk, int rate, int *out)
{
        /* sclk must be derived from mclk! */
        if (mclk % sclk)
                return -1;
        /* derive sclk register value */
        if (i2s_sf_sclkdiv(mclk / sclk, out))
                return -1;

        if (I2S_CLOCK_SPEED_18MHz % (rate * mclk) == 0) {
                if (!i2s_sf_mclkdiv(I2S_CLOCK_SPEED_18MHz / (rate * mclk), out)) {
                        *out |= I2S_SF_CLOCK_SOURCE_18MHz;
                        return 0;
                }
        }
        if (I2S_CLOCK_SPEED_45MHz % (rate * mclk) == 0) {
                if (!i2s_sf_mclkdiv(I2S_CLOCK_SPEED_45MHz / (rate * mclk), out)) {
                        *out |= I2S_SF_CLOCK_SOURCE_45MHz;
                        return 0;
                }
        }
        if (I2S_CLOCK_SPEED_49MHz % (rate * mclk) == 0) {
                if (!i2s_sf_mclkdiv(I2S_CLOCK_SPEED_49MHz / (rate * mclk), out)) {
                        *out |= I2S_SF_CLOCK_SOURCE_49MHz;
                        return 0;
                }
        }
        return -1;
}

#define CHECK_RATE(rate)                                                \
        do { if (rates & SNDRV_PCM_RATE_ ##rate) {                      \
                int dummy;                                              \
                if (clock_and_divisors(sysclock_factor,                 \
                                       bus_factor, rate, &dummy))       \
                        rates &= ~SNDRV_PCM_RATE_ ##rate;               \
        } } while (0)

static int i2sbus_pcm_open(struct i2sbus_dev *i2sdev, int in)
{
        struct pcm_info *pi, *other;
        struct soundbus_dev *sdev;
        int masks_inited = 0, err;
        struct codec_info_item *cii, *rev;
        struct snd_pcm_hardware *hw;
        u64 formats = 0;
        unsigned int rates = 0;
        struct transfer_info v;
        int result = 0;
        int bus_factor = 0, sysclock_factor = 0;
        int found_this;

        mutex_lock(&i2sdev->lock);

        get_pcm_info(i2sdev, in, &pi, &other);

        hw = &pi->substream->runtime->hw;
        sdev = &i2sdev->sound;

        if (pi->active) {
                /* alsa messed up */
                result = -EBUSY;
                goto out_unlock;
        }

        /* we now need to assign the hw */
        list_for_each_entry(cii, &sdev->codec_list, list) {
                struct transfer_info *ti = cii->codec->transfers;
                bus_factor = cii->codec->bus_factor;
                sysclock_factor = cii->codec->sysclock_factor;
                while (ti->formats && ti->rates) {
                        v = *ti;
                        if (ti->transfer_in == in
                            && cii->codec->usable(cii, ti, &v)) {
                                if (masks_inited) {
                                        formats &= v.formats;
                                        rates &= v.rates;
                                } else {
                                        formats = v.formats;
                                        rates = v.rates;
                                        masks_inited = 1;
                                }
                        }
                        ti++;
                }
        }
        if (!masks_inited || !bus_factor || !sysclock_factor) {
                result = -ENODEV;
                goto out_unlock;
        }
        /* bus dependent stuff */
        hw->info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
                   SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_RESUME |
                   SNDRV_PCM_INFO_JOINT_DUPLEX;

        CHECK_RATE(5512);
        CHECK_RATE(8000);
        CHECK_RATE(11025);
        CHECK_RATE(16000);
        CHECK_RATE(22050);
        CHECK_RATE(32000);
        CHECK_RATE(44100);
        CHECK_RATE(48000);
        CHECK_RATE(64000);
        CHECK_RATE(88200);
        CHECK_RATE(96000);
        CHECK_RATE(176400);
        CHECK_RATE(192000);
        hw->rates = rates;

        /* well. the codec might want 24 bits only, and we'll
         * ever only transfer 24 bits, but they are top-aligned!
         * So for alsa, we claim that we're doing full 32 bit
         * while in reality we'll ignore the lower 8 bits of
         * that when doing playback (they're transferred as 0
         * as far as I know, no codecs we have are 32-bit capable
         * so I can't really test) and when doing recording we'll
         * always have those lower 8 bits recorded as 0 */
        if (formats & SNDRV_PCM_FMTBIT_S24_BE)
                formats |= SNDRV_PCM_FMTBIT_S32_BE;
        if (formats & SNDRV_PCM_FMTBIT_U24_BE)
                formats |= SNDRV_PCM_FMTBIT_U32_BE;
        /* now mask off what we can support. I suppose we could
         * also support S24_3LE and some similar formats, but I
         * doubt there's a codec that would be able to use that,
         * so we don't support it here. */
        hw->formats = formats & (SNDRV_PCM_FMTBIT_S16_BE |
                                 SNDRV_PCM_FMTBIT_U16_BE |
                                 SNDRV_PCM_FMTBIT_S32_BE |
                                 SNDRV_PCM_FMTBIT_U32_BE);

        /* we need to set the highest and lowest rate possible.
         * These are the highest and lowest rates alsa can
         * support properly in its bitfield.
         * Below, we'll use that to restrict to the rate
         * currently in use (if any). */
        hw->rate_min = 5512;
        hw->rate_max = 192000;
        /* if the other stream is active, then we can only
         * support what it is currently using.
         * FIXME: I lied. This comment is wrong. We can support
         * anything that works with the same serial format, ie.
         * when recording 24 bit sound we can well play 16 bit
         * sound at the same time iff using the same transfer mode.
         */
        if (other->active) {
                /* FIXME: is this guaranteed by the alsa api? */
                hw->formats &= (1ULL << i2sdev->format);
                /* see above, restrict rates to the one we already have */
                hw->rate_min = i2sdev->rate;
                hw->rate_max = i2sdev->rate;
        }

        hw->channels_min = 2;
        hw->channels_max = 2;
        /* these are somewhat arbitrary */
        hw->buffer_bytes_max = 131072;
        hw->period_bytes_min = 256;
        hw->period_bytes_max = 16384;
        hw->periods_min = 3;
        hw->periods_max = MAX_DBDMA_COMMANDS;
        err = snd_pcm_hw_constraint_integer(pi->substream->runtime,
                                            SNDRV_PCM_HW_PARAM_PERIODS);
        if (err < 0) {
                result = err;
                goto out_unlock;
        }
        list_for_each_entry(cii, &sdev->codec_list, list) {
                if (cii->codec->open) {
                        err = cii->codec->open(cii, pi->substream);
                        if (err) {
                                result = err;
                                /* unwind */
                                found_this = 0;
                                list_for_each_entry_reverse(rev,
                                    &sdev->codec_list, list) {
                                        if (found_this && rev->codec->close) {
                                                rev->codec->close(rev,
                                                                pi->substream);
                                        }
                                        if (rev == cii)
                                                found_this = 1;
                                }
                                goto out_unlock;
                        }
                }
        }

 out_unlock:
        mutex_unlock(&i2sdev->lock);
        return result;
}

#undef CHECK_RATE

static int i2sbus_pcm_close(struct i2sbus_dev *i2sdev, int in)
{
        struct codec_info_item *cii;
        struct pcm_info *pi;
        int err = 0, tmp;

        mutex_lock(&i2sdev->lock);

        get_pcm_info(i2sdev, in, &pi, NULL);

        list_for_each_entry(cii, &i2sdev->sound.codec_list, list) {
                if (cii->codec->close) {
                        tmp = cii->codec->close(cii, pi->substream);
                        if (tmp)
                                err = tmp;
                }
        }

        pi->substream = NULL;
        pi->active = 0;
        mutex_unlock(&i2sdev->lock);
        return err;
}

static void i2sbus_wait_for_stop(struct i2sbus_dev *i2sdev,
                                 struct pcm_info *pi)
{
        unsigned long flags;
        struct completion done;
        long timeout;

        spin_lock_irqsave(&i2sdev->low_lock, flags);
        if (pi->dbdma_ring.stopping) {
                init_completion(&done);
                pi->stop_completion = &done;
                spin_unlock_irqrestore(&i2sdev->low_lock, flags);
                timeout = wait_for_completion_timeout(&done, HZ);
                spin_lock_irqsave(&i2sdev->low_lock, flags);
                pi->stop_completion = NULL;
                if (timeout == 0) {
                        /* timeout expired, stop dbdma forcefully */
                        printk(KERN_ERR "i2sbus_wait_for_stop: timed out\n");
                        /* make sure RUN, PAUSE and S0 bits are cleared */
                        out_le32(&pi->dbdma->control, (RUN | PAUSE | 1) << 16);
                        pi->dbdma_ring.stopping = 0;
                        timeout = 10;
                        while (in_le32(&pi->dbdma->status) & ACTIVE) {
                                if (--timeout <= 0)
                                        break;
                                udelay(1);
                        }
                }
        }
        spin_unlock_irqrestore(&i2sdev->low_lock, flags);
}

#ifdef CONFIG_PM
void i2sbus_wait_for_stop_both(struct i2sbus_dev *i2sdev)
{
        struct pcm_info *pi;

        get_pcm_info(i2sdev, 0, &pi, NULL);
        i2sbus_wait_for_stop(i2sdev, pi);
        get_pcm_info(i2sdev, 1, &pi, NULL);
        i2sbus_wait_for_stop(i2sdev, pi);
}
#endif

static int i2sbus_hw_params(struct snd_pcm_substream *substream,
                            struct snd_pcm_hw_params *params)
{
        return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
}

static inline int i2sbus_hw_free(struct snd_pcm_substream *substream, int in)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);
        struct pcm_info *pi;

        get_pcm_info(i2sdev, in, &pi, NULL);
        if (pi->dbdma_ring.stopping)
                i2sbus_wait_for_stop(i2sdev, pi);
        snd_pcm_lib_free_pages(substream);
        return 0;
}

static int i2sbus_playback_hw_free(struct snd_pcm_substream *substream)
{
        return i2sbus_hw_free(substream, 0);
}

static int i2sbus_record_hw_free(struct snd_pcm_substream *substream)
{
        return i2sbus_hw_free(substream, 1);
}

static int i2sbus_pcm_prepare(struct i2sbus_dev *i2sdev, int in)
{
        /* whee. Hard work now. The user has selected a bitrate
         * and bit format, so now we have to program our
         * I2S controller appropriately. */
        struct snd_pcm_runtime *runtime;
        struct dbdma_cmd *command;
        int i, periodsize, nperiods;
        dma_addr_t offset;
        struct bus_info bi;
        struct codec_info_item *cii;
        int sfr = 0;            /* serial format register */
        int dws = 0;            /* data word sizes reg */
        int input_16bit;
        struct pcm_info *pi, *other;
        int cnt;
        int result = 0;
        unsigned int cmd, stopaddr;

        mutex_lock(&i2sdev->lock);

        get_pcm_info(i2sdev, in, &pi, &other);

        if (pi->dbdma_ring.running) {
                result = -EBUSY;
                goto out_unlock;
        }
        if (pi->dbdma_ring.stopping)
                i2sbus_wait_for_stop(i2sdev, pi);

        if (!pi->substream || !pi->substream->runtime) {
                result = -EINVAL;
                goto out_unlock;
        }

        runtime = pi->substream->runtime;
        pi->active = 1;
        if (other->active &&
            ((i2sdev->format != runtime->format)
             || (i2sdev->rate != runtime->rate))) {
                result = -EINVAL;
                goto out_unlock;
        }

        i2sdev->format = runtime->format;
        i2sdev->rate = runtime->rate;

        periodsize = snd_pcm_lib_period_bytes(pi->substream);
        nperiods = pi->substream->runtime->periods;
        pi->current_period = 0;

        /* generate dbdma command ring first */
        command = pi->dbdma_ring.cmds;
        memset(command, 0, (nperiods + 2) * sizeof(struct dbdma_cmd));

        /* commands to DMA to/from the ring */
        /*
         * For input, we need to do a graceful stop; if we abort
         * the DMA, we end up with leftover bytes that corrupt
         * the next recording.  To do this we set the S0 status
         * bit and wait for the DMA controller to stop.  Each
         * command has a branch condition to
         * make it branch to a stop command if S0 is set.
         * On input we also need to wait for the S7 bit to be
         * set before turning off the DMA controller.
         * In fact we do the graceful stop for output as well.
         */
        offset = runtime->dma_addr;
        cmd = (in? INPUT_MORE: OUTPUT_MORE) | BR_IFSET | INTR_ALWAYS;
        stopaddr = pi->dbdma_ring.bus_cmd_start +
                (nperiods + 1) * sizeof(struct dbdma_cmd);
        for (i = 0; i < nperiods; i++, command++, offset += periodsize) {
                command->command = cpu_to_le16(cmd);
                command->cmd_dep = cpu_to_le32(stopaddr);
                command->phy_addr = cpu_to_le32(offset);
                command->req_count = cpu_to_le16(periodsize);
        }

        /* branch back to beginning of ring */
        command->command = cpu_to_le16(DBDMA_NOP | BR_ALWAYS);
        command->cmd_dep = cpu_to_le32(pi->dbdma_ring.bus_cmd_start);
        command++;

        /* set stop command */
        command->command = cpu_to_le16(DBDMA_STOP);

        /* ok, let's set the serial format and stuff */
        switch (runtime->format) {
        /* 16 bit formats */
        case SNDRV_PCM_FORMAT_S16_BE:
        case SNDRV_PCM_FORMAT_U16_BE:
                /* FIXME: if we add different bus factors we need to
                 * do more here!! */
                bi.bus_factor = 0;
                list_for_each_entry(cii, &i2sdev->sound.codec_list, list) {
                        bi.bus_factor = cii->codec->bus_factor;
                        break;
                }
                if (!bi.bus_factor) {
                        result = -ENODEV;
                        goto out_unlock;
                }
                input_16bit = 1;
                break;
        case SNDRV_PCM_FORMAT_S32_BE:
        case SNDRV_PCM_FORMAT_U32_BE:
                /* force 64x bus speed, otherwise the data cannot be
                 * transferred quickly enough! */
                bi.bus_factor = 64;
                input_16bit = 0;
                break;
        default:
                result = -EINVAL;
                goto out_unlock;
        }
        /* we assume all sysclocks are the same! */
        list_for_each_entry(cii, &i2sdev->sound.codec_list, list) {
                bi.sysclock_factor = cii->codec->sysclock_factor;
                break;
        }

        if (clock_and_divisors(bi.sysclock_factor,
                               bi.bus_factor,
                               runtime->rate,
                               &sfr) < 0) {
                result = -EINVAL;
                goto out_unlock;
        }
        switch (bi.bus_factor) {
        case 32:
                sfr |= I2S_SF_SERIAL_FORMAT_I2S_32X;
                break;
        case 64:
                sfr |= I2S_SF_SERIAL_FORMAT_I2S_64X;
                break;
        }
        /* FIXME: THIS ASSUMES MASTER ALL THE TIME */
        sfr |= I2S_SF_SCLK_MASTER;

        list_for_each_entry(cii, &i2sdev->sound.codec_list, list) {
                int err = 0;
                if (cii->codec->prepare)
                        err = cii->codec->prepare(cii, &bi, pi->substream);
                if (err) {
                        result = err;
                        goto out_unlock;
                }
        }
        /* codecs are fine with it, so set our clocks */
        if (input_16bit)
                dws =   (2 << I2S_DWS_NUM_CHANNELS_IN_SHIFT) |
                        (2 << I2S_DWS_NUM_CHANNELS_OUT_SHIFT) |
                        I2S_DWS_DATA_IN_16BIT | I2S_DWS_DATA_OUT_16BIT;
        else
                dws =   (2 << I2S_DWS_NUM_CHANNELS_IN_SHIFT) |
                        (2 << I2S_DWS_NUM_CHANNELS_OUT_SHIFT) |
                        I2S_DWS_DATA_IN_24BIT | I2S_DWS_DATA_OUT_24BIT;

        /* early exit if already programmed correctly */
        /* not locking these is fine since we touch them only in this function */
        if (in_le32(&i2sdev->intfregs->serial_format) == sfr
         && in_le32(&i2sdev->intfregs->data_word_sizes) == dws)
                goto out_unlock;

        /* let's notify the codecs about clocks going away.
         * For now we only do mastering on the i2s cell... */
        list_for_each_entry(cii, &i2sdev->sound.codec_list, list)
                if (cii->codec->switch_clock)
                        cii->codec->switch_clock(cii, CLOCK_SWITCH_PREPARE_SLAVE);

        i2sbus_control_enable(i2sdev->control, i2sdev);
        i2sbus_control_cell(i2sdev->control, i2sdev, 1);

        out_le32(&i2sdev->intfregs->intr_ctl, I2S_PENDING_CLOCKS_STOPPED);

        i2sbus_control_clock(i2sdev->control, i2sdev, 0);

        msleep(1);

        /* wait for clock stopped. This can apparently take a while... */
        cnt = 100;
        while (cnt-- &&
            !(in_le32(&i2sdev->intfregs->intr_ctl) & I2S_PENDING_CLOCKS_STOPPED)) {
                msleep(5);
        }
        out_le32(&i2sdev->intfregs->intr_ctl, I2S_PENDING_CLOCKS_STOPPED);

        /* not locking these is fine since we touch them only in this function */
        out_le32(&i2sdev->intfregs->serial_format, sfr);
        out_le32(&i2sdev->intfregs->data_word_sizes, dws);

        i2sbus_control_enable(i2sdev->control, i2sdev);
        i2sbus_control_cell(i2sdev->control, i2sdev, 1);
        i2sbus_control_clock(i2sdev->control, i2sdev, 1);
        msleep(1);

        list_for_each_entry(cii, &i2sdev->sound.codec_list, list)
                if (cii->codec->switch_clock)
                        cii->codec->switch_clock(cii, CLOCK_SWITCH_SLAVE);

 out_unlock:
        mutex_unlock(&i2sdev->lock);
        return result;
}

#ifdef CONFIG_PM
void i2sbus_pcm_prepare_both(struct i2sbus_dev *i2sdev)
{
        i2sbus_pcm_prepare(i2sdev, 0);
        i2sbus_pcm_prepare(i2sdev, 1);
}
#endif

static int i2sbus_pcm_trigger(struct i2sbus_dev *i2sdev, int in, int cmd)
{
        struct codec_info_item *cii;
        struct pcm_info *pi;
        int result = 0;
        unsigned long flags;

        spin_lock_irqsave(&i2sdev->low_lock, flags);

        get_pcm_info(i2sdev, in, &pi, NULL);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
                if (pi->dbdma_ring.running) {
                        result = -EALREADY;
                        goto out_unlock;
                }
                list_for_each_entry(cii, &i2sdev->sound.codec_list, list)
                        if (cii->codec->start)
                                cii->codec->start(cii, pi->substream);
                pi->dbdma_ring.running = 1;

                if (pi->dbdma_ring.stopping) {
                        /* Clear the S0 bit, then see if we stopped yet */
                        out_le32(&pi->dbdma->control, 1 << 16);
                        if (in_le32(&pi->dbdma->status) & ACTIVE) {
                                /* possible race here? */
                                udelay(10);
                                if (in_le32(&pi->dbdma->status) & ACTIVE) {
                                        pi->dbdma_ring.stopping = 0;
                                        goto out_unlock; /* keep running */
                                }
                        }
                }

                /* make sure RUN, PAUSE and S0 bits are cleared */
                out_le32(&pi->dbdma->control, (RUN | PAUSE | 1) << 16);

                /* set branch condition select register */
                out_le32(&pi->dbdma->br_sel, (1 << 16) | 1);

                /* write dma command buffer address to the dbdma chip */
                out_le32(&pi->dbdma->cmdptr, pi->dbdma_ring.bus_cmd_start);

                /* initialize the frame count and current period */
                pi->current_period = 0;
                pi->frame_count = in_le32(&i2sdev->intfregs->frame_count);

                /* set the DMA controller running */
                out_le32(&pi->dbdma->control, (RUN << 16) | RUN);

                /* off you go! */
                break;

        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_SUSPEND:
                if (!pi->dbdma_ring.running) {
                        result = -EALREADY;
                        goto out_unlock;
                }
                pi->dbdma_ring.running = 0;

                /* Set the S0 bit to make the DMA branch to the stop cmd */
                out_le32(&pi->dbdma->control, (1 << 16) | 1);
                pi->dbdma_ring.stopping = 1;

                list_for_each_entry(cii, &i2sdev->sound.codec_list, list)
                        if (cii->codec->stop)
                                cii->codec->stop(cii, pi->substream);
                break;
        default:
                result = -EINVAL;
                goto out_unlock;
        }

 out_unlock:
        spin_unlock_irqrestore(&i2sdev->low_lock, flags);
        return result;
}

static snd_pcm_uframes_t i2sbus_pcm_pointer(struct i2sbus_dev *i2sdev, int in)
{
        struct pcm_info *pi;
        u32 fc;

        get_pcm_info(i2sdev, in, &pi, NULL);

        fc = in_le32(&i2sdev->intfregs->frame_count);
        fc = fc - pi->frame_count;

        if (fc >= pi->substream->runtime->buffer_size)
                fc %= pi->substream->runtime->buffer_size;
        return fc;
}

static inline void handle_interrupt(struct i2sbus_dev *i2sdev, int in)
{
        struct pcm_info *pi;
        u32 fc, nframes;
        u32 status;
        int timeout, i;
        int dma_stopped = 0;
        struct snd_pcm_runtime *runtime;

        spin_lock(&i2sdev->low_lock);
        get_pcm_info(i2sdev, in, &pi, NULL);
        if (!pi->dbdma_ring.running && !pi->dbdma_ring.stopping)
                goto out_unlock;

        i = pi->current_period;
        runtime = pi->substream->runtime;
        while (pi->dbdma_ring.cmds[i].xfer_status) {
                if (le16_to_cpu(pi->dbdma_ring.cmds[i].xfer_status) & BT)
                        /*
                         * BT is the branch taken bit.  If it took a branch
                         * it is because we set the S0 bit to make it
                         * branch to the stop command.
                         */
                        dma_stopped = 1;
                pi->dbdma_ring.cmds[i].xfer_status = 0;

                if (++i >= runtime->periods) {
                        i = 0;
                        pi->frame_count += runtime->buffer_size;
                }
                pi->current_period = i;

                /*
                 * Check the frame count.  The DMA tends to get a bit
                 * ahead of the frame counter, which confuses the core.
                 */
                fc = in_le32(&i2sdev->intfregs->frame_count);
                nframes = i * runtime->period_size;
                if (fc < pi->frame_count + nframes)
                        pi->frame_count = fc - nframes;
        }

        if (dma_stopped) {
                timeout = 1000;
                for (;;) {
                        status = in_le32(&pi->dbdma->status);
                        if (!(status & ACTIVE) && (!in || (status & 0x80)))
                                break;
                        if (--timeout <= 0) {
                                printk(KERN_ERR "i2sbus: timed out "
                                       "waiting for DMA to stop!\n");
                                break;
                        }
                        udelay(1);
                }

                /* Turn off DMA controller, clear S0 bit */
                out_le32(&pi->dbdma->control, (RUN | PAUSE | 1) << 16);

                pi->dbdma_ring.stopping = 0;
                if (pi->stop_completion)
                        complete(pi->stop_completion);
        }

        if (!pi->dbdma_ring.running)
                goto out_unlock;
        spin_unlock(&i2sdev->low_lock);
        /* may call _trigger again, hence needs to be unlocked */
        snd_pcm_period_elapsed(pi->substream);
        return;

 out_unlock:
        spin_unlock(&i2sdev->low_lock);
}

irqreturn_t i2sbus_tx_intr(int irq, void *devid)
{
        handle_interrupt((struct i2sbus_dev *)devid, 0);
        return IRQ_HANDLED;
}

irqreturn_t i2sbus_rx_intr(int irq, void *devid)
{
        handle_interrupt((struct i2sbus_dev *)devid, 1);
        return IRQ_HANDLED;
}

static int i2sbus_playback_open(struct snd_pcm_substream *substream)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);

        if (!i2sdev)
                return -EINVAL;
        i2sdev->out.substream = substream;
        return i2sbus_pcm_open(i2sdev, 0);
}

static int i2sbus_playback_close(struct snd_pcm_substream *substream)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);
        int err;

        if (!i2sdev)
                return -EINVAL;
        if (i2sdev->out.substream != substream)
                return -EINVAL;
        err = i2sbus_pcm_close(i2sdev, 0);
        if (!err)
                i2sdev->out.substream = NULL;
        return err;
}

static int i2sbus_playback_prepare(struct snd_pcm_substream *substream)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);

        if (!i2sdev)
                return -EINVAL;
        if (i2sdev->out.substream != substream)
                return -EINVAL;
        return i2sbus_pcm_prepare(i2sdev, 0);
}

static int i2sbus_playback_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);

        if (!i2sdev)
                return -EINVAL;
        if (i2sdev->out.substream != substream)
                return -EINVAL;
        return i2sbus_pcm_trigger(i2sdev, 0, cmd);
}

static snd_pcm_uframes_t i2sbus_playback_pointer(struct snd_pcm_substream
                                                 *substream)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);

        if (!i2sdev)
                return -EINVAL;
        if (i2sdev->out.substream != substream)
                return 0;
        return i2sbus_pcm_pointer(i2sdev, 0);
}

static struct snd_pcm_ops i2sbus_playback_ops = {
        .open =         i2sbus_playback_open,
        .close =        i2sbus_playback_close,
        .ioctl =        snd_pcm_lib_ioctl,
        .hw_params =    i2sbus_hw_params,
        .hw_free =      i2sbus_playback_hw_free,
        .prepare =      i2sbus_playback_prepare,
        .trigger =      i2sbus_playback_trigger,
        .pointer =      i2sbus_playback_pointer,
};

static int i2sbus_record_open(struct snd_pcm_substream *substream)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);

        if (!i2sdev)
                return -EINVAL;
        i2sdev->in.substream = substream;
        return i2sbus_pcm_open(i2sdev, 1);
}

static int i2sbus_record_close(struct snd_pcm_substream *substream)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);
        int err;

        if (!i2sdev)
                return -EINVAL;
        if (i2sdev->in.substream != substream)
                return -EINVAL;
        err = i2sbus_pcm_close(i2sdev, 1);
        if (!err)
                i2sdev->in.substream = NULL;
        return err;
}

static int i2sbus_record_prepare(struct snd_pcm_substream *substream)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);

        if (!i2sdev)
                return -EINVAL;
        if (i2sdev->in.substream != substream)
                return -EINVAL;
        return i2sbus_pcm_prepare(i2sdev, 1);
}

static int i2sbus_record_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);

        if (!i2sdev)
                return -EINVAL;
        if (i2sdev->in.substream != substream)
                return -EINVAL;
        return i2sbus_pcm_trigger(i2sdev, 1, cmd);
}

static snd_pcm_uframes_t i2sbus_record_pointer(struct snd_pcm_substream
                                               *substream)
{
        struct i2sbus_dev *i2sdev = snd_pcm_substream_chip(substream);

        if (!i2sdev)
                return -EINVAL;
        if (i2sdev->in.substream != substream)
                return 0;
        return i2sbus_pcm_pointer(i2sdev, 1);
}

static struct snd_pcm_ops i2sbus_record_ops = {
        .open =         i2sbus_record_open,
        .close =        i2sbus_record_close,
        .ioctl =        snd_pcm_lib_ioctl,
        .hw_params =    i2sbus_hw_params,
        .hw_free =      i2sbus_record_hw_free,
        .prepare =      i2sbus_record_prepare,
        .trigger =      i2sbus_record_trigger,
        .pointer =      i2sbus_record_pointer,
};

static void i2sbus_private_free(struct snd_pcm *pcm)
{
        struct i2sbus_dev *i2sdev = snd_pcm_chip(pcm);
        struct codec_info_item *p, *tmp;

        i2sdev->sound.pcm = NULL;
        i2sdev->out.created = 0;
        i2sdev->in.created = 0;
        list_for_each_entry_safe(p, tmp, &i2sdev->sound.codec_list, list) {
                printk(KERN_ERR "i2sbus: a codec didn't unregister!\n");
                list_del(&p->list);
                module_put(p->codec->owner);
                kfree(p);
        }
        soundbus_dev_put(&i2sdev->sound);
        module_put(THIS_MODULE);
}

int
i2sbus_attach_codec(struct soundbus_dev *dev, struct snd_card *card,
                    struct codec_info *ci, void *data)
{
        int err, in = 0, out = 0;
        struct transfer_info *tmp;
        struct i2sbus_dev *i2sdev = soundbus_dev_to_i2sbus_dev(dev);
        struct codec_info_item *cii;

        if (!dev->pcmname || dev->pcmid == -1) {
                printk(KERN_ERR "i2sbus: pcm name and id must be set!\n");
                return -EINVAL;
        }

        list_for_each_entry(cii, &dev->codec_list, list) {
                if (cii->codec_data == data)
                        return -EALREADY;
        }

        if (!ci->transfers || !ci->transfers->formats
            || !ci->transfers->rates || !ci->usable)
                return -EINVAL;

        /* we currently code the i2s transfer on the clock, and support only
         * 32 and 64 */
        if (ci->bus_factor != 32 && ci->bus_factor != 64)
                return -EINVAL;

        /* If you want to fix this, you need to keep track of what transport infos
         * are to be used, which codecs they belong to, and then fix all the
         * sysclock/busclock stuff above to depend on which is usable */
        list_for_each_entry(cii, &dev->codec_list, list) {
                if (cii->codec->sysclock_factor != ci->sysclock_factor) {
                        printk(KERN_DEBUG
                               "cannot yet handle multiple different sysclocks!\n");
                        return -EINVAL;
                }
                if (cii->codec->bus_factor != ci->bus_factor) {
                        printk(KERN_DEBUG
                               "cannot yet handle multiple different bus clocks!\n");
                        return -EINVAL;
                }
        }

        tmp = ci->transfers;
        while (tmp->formats && tmp->rates) {
                if (tmp->transfer_in)
                        in = 1;
                else
                        out = 1;
                tmp++;
        }

        cii = kzalloc(sizeof(struct codec_info_item), GFP_KERNEL);
        if (!cii) {
                printk(KERN_DEBUG "i2sbus: failed to allocate cii\n");
                return -ENOMEM;
        }

        /* use the private data to point to the codec info */
        cii->sdev = soundbus_dev_get(dev);
        cii->codec = ci;
        cii->codec_data = data;

        if (!cii->sdev) {
                printk(KERN_DEBUG
                       "i2sbus: failed to get soundbus dev reference\n");
                err = -ENODEV;
                goto out_free_cii;
        }

        if (!try_module_get(THIS_MODULE)) {
                printk(KERN_DEBUG "i2sbus: failed to get module reference!\n");
                err = -EBUSY;
                goto out_put_sdev;
        }

        if (!try_module_get(ci->owner)) {
                printk(KERN_DEBUG
                       "i2sbus: failed to get module reference to codec owner!\n");
                err = -EBUSY;
                goto out_put_this_module;
        }

        if (!dev->pcm) {
                err = snd_pcm_new(card, dev->pcmname, dev->pcmid, 0, 0,
                                  &dev->pcm);
                if (err) {
                        printk(KERN_DEBUG "i2sbus: failed to create pcm\n");
                        goto out_put_ci_module;
                }
                dev->pcm->dev = &dev->ofdev.dev;
        }

        /* ALSA yet again sucks.
         * If it is ever fixed, remove this line. See below. */
        out = in = 1;

        if (!i2sdev->out.created && out) {
                if (dev->pcm->card != card) {
                        /* eh? */
                        printk(KERN_ERR
                               "Can't attach same bus to different cards!\n");
                        err = -EINVAL;
                        goto out_put_ci_module;
                }
                err = snd_pcm_new_stream(dev->pcm, SNDRV_PCM_STREAM_PLAYBACK, 1);
                if (err)
                        goto out_put_ci_module;
                snd_pcm_set_ops(dev->pcm, SNDRV_PCM_STREAM_PLAYBACK,
                                &i2sbus_playback_ops);
                i2sdev->out.created = 1;
        }

        if (!i2sdev->in.created && in) {
                if (dev->pcm->card != card) {
                        printk(KERN_ERR
                               "Can't attach same bus to different cards!\n");
                        err = -EINVAL;
                        goto out_put_ci_module;
                }
                err = snd_pcm_new_stream(dev->pcm, SNDRV_PCM_STREAM_CAPTURE, 1);
                if (err)
                        goto out_put_ci_module;
                snd_pcm_set_ops(dev->pcm, SNDRV_PCM_STREAM_CAPTURE,
                                &i2sbus_record_ops);
                i2sdev->in.created = 1;
        }

        /* so we have to register the pcm after adding any substream
         * to it because alsa doesn't create the devices for the
         * substreams when we add them later.
         * Therefore, force in and out on both busses (above) and
         * register the pcm now instead of just after creating it.
         */
        err = snd_device_register(card, dev->pcm);
        if (err) {
                printk(KERN_ERR "i2sbus: error registering new pcm\n");
                goto out_put_ci_module;
        }
        /* no errors any more, so let's add this to our list */
        list_add(&cii->list, &dev->codec_list);

        dev->pcm->private_data = i2sdev;
        dev->pcm->private_free = i2sbus_private_free;

        /* well, we really should support scatter/gather DMA */
        snd_pcm_lib_preallocate_pages_for_all(
                dev->pcm, SNDRV_DMA_TYPE_DEV,
                snd_dma_pci_data(macio_get_pci_dev(i2sdev->macio)),
                64 * 1024, 64 * 1024);

        return 0;
 out_put_ci_module:
        module_put(ci->owner);
 out_put_this_module:
        module_put(THIS_MODULE);
 out_put_sdev:
        soundbus_dev_put(dev);
 out_free_cii:
        kfree(cii);
        return err;
}

void i2sbus_detach_codec(struct soundbus_dev *dev, void *data)
{
        struct codec_info_item *cii = NULL, *i;

        list_for_each_entry(i, &dev->codec_list, list) {
                if (i->codec_data == data) {
                        cii = i;
                        break;
                }
        }
        if (cii) {
                list_del(&cii->list);
                module_put(cii->codec->owner);
                kfree(cii);
        }
        /* no more codecs, but still a pcm? */
        if (list_empty(&dev->codec_list) && dev->pcm) {
                /* the actual cleanup is done by the callback above! */
                snd_device_free(dev->pcm->card, dev->pcm);
        }
}