Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / sound / aoa / soundbus / i2sbus / pcm.c
diff --git a/kernel/sound/aoa/soundbus/i2sbus/pcm.c b/kernel/sound/aoa/soundbus/i2sbus/pcm.c
new file mode 100644 (file)
index 0000000..053b09c
--- /dev/null
@@ -0,0 +1,1067 @@
+/*
+ * i2sbus driver -- pcm routines
+ *
+ * Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
+ *
+ * GPL v2, can be found in COPYING.
+ */
+
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <sound/core.h>
+#include <asm/macio.h>
+#include <linux/pci.h>
+#include <linux/module.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 &= pcm_format_to_bits(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;
+               }
+       }
+
+       /* 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);
+               dev->pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].dev.parent =
+                       &dev->ofdev.dev;
+               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);
+               dev->pcm->streams[SNDRV_PCM_STREAM_CAPTURE].dev.parent =
+                       &dev->ofdev.dev;
+               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);
+       }
+}