[ALSA] snd-aoa: add snd-aoa

This large patch adds all of snd-aoa.
Consisting of many modules, it currently replaces snd-powermac
for all layout-id based machines and handles many more (for
example new powerbooks and powermacs with digital output that
previously couldn't be used at all).
It also has support for all layout-IDs that Apple has (judging
from their Info.plist file) but not all are tested.
The driver currently has 2 known regressions over snd-powermac:
 * it doesn't handle powermac 7,2 and 7,3
 * it doesn't have a DRC control on snapper-based machines
I will fix those during the 2.6.18 development cycle.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 1021 insertions, 0 deletions

diff --git a/sound/aoa/soundbus/i2sbus/i2sbus-pcm.c b/sound/aoa/soundbus/i2sbus/i2sbus-pcm.c
new file mode 100644
index 000000000000..3049015a04f1
--- /dev/null
+++ b/sound/aoa/soundbus/i2sbus/i2sbus-pcm.c
@@ -0,0 +1,1021 @@
+/*
+ * 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>
+/* So apparently there's a reason for requiring driver.h
+ * to be included first, even if I don't know it... */
+#include <sound/driver.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;
+
+	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;
+	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 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 int i2sbus_hw_free(struct snd_pcm_substream *substream)
+{
+	snd_pcm_lib_free_pages(substream);
+	return 0;
+}
+
+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;
+	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;
+
+	mutex_lock(&i2sdev->lock);
+
+	get_pcm_info(i2sdev, in, &pi, &other);
+
+	if (pi->dbdma_ring.running) {
+		result = -EBUSY;
+		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);
+	pi->current_period = 0;
+
+	/* generate dbdma command ring first */
+	command = pi->dbdma_ring.cmds;
+	offset = runtime->dma_addr;
+	for (i = 0; i < pi->substream->runtime->periods;
+	     i++, command++, offset += periodsize) {
+		memset(command, 0, sizeof(struct dbdma_cmd));
+		command->command =
+		    cpu_to_le16((in ? INPUT_MORE : OUTPUT_MORE) | INTR_ALWAYS);
+		command->phy_addr = cpu_to_le32(offset);
+		command->req_count = cpu_to_le16(periodsize);
+		command->xfer_status = cpu_to_le16(0);
+	}
+	/* last one branches back to first */
+	command--;
+	command->command |= cpu_to_le16(BR_ALWAYS);
+	command->cmd_dep = cpu_to_le32(pi->dbdma_ring.bus_cmd_start);
+
+	/* 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;
+}
+
+static struct dbdma_cmd STOP_CMD = {
+	.command = __constant_cpu_to_le16(DBDMA_STOP),
+};
+
+static int i2sbus_pcm_trigger(struct i2sbus_dev *i2sdev, int in, int cmd)
+{
+	struct codec_info_item *cii;
+	struct pcm_info *pi;
+	int timeout;
+	struct dbdma_cmd tmp;
+	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;
+
+		/* reset dma engine */
+		out_le32(&pi->dbdma->control,
+			 0 | (RUN | PAUSE | FLUSH | WAKE) << 16);
+		timeout = 100;
+		while (in_le32(&pi->dbdma->status) & RUN && timeout--)
+			udelay(1);
+		if (timeout <= 0) {
+			printk(KERN_ERR
+			       "i2sbus: error waiting for dma reset\n");
+			result = -ENXIO;
+			goto out_unlock;
+		}
+
+		/* write dma command buffer address to the dbdma chip */
+		out_le32(&pi->dbdma->cmdptr, pi->dbdma_ring.bus_cmd_start);
+		/* post PCI write */
+		mb();
+		(void)in_le32(&pi->dbdma->status);
+
+		/* change first command to STOP */
+		tmp = *pi->dbdma_ring.cmds;
+		*pi->dbdma_ring.cmds = STOP_CMD;
+
+		/* set running state, remember that the first command is STOP */
+		out_le32(&pi->dbdma->control, RUN | (RUN << 16));
+		timeout = 100;
+		/* wait for STOP to be executed */
+		while (in_le32(&pi->dbdma->status) & ACTIVE && timeout--)
+			udelay(1);
+		if (timeout <= 0) {
+			printk(KERN_ERR "i2sbus: error waiting for dma stop\n");
+			result = -ENXIO;
+			goto out_unlock;
+		}
+		/* again, write dma command buffer address to the dbdma chip,
+		 * this time of the first real command */
+		*pi->dbdma_ring.cmds = tmp;
+		out_le32(&pi->dbdma->cmdptr, pi->dbdma_ring.bus_cmd_start);
+		/* post write */
+		mb();
+		(void)in_le32(&pi->dbdma->status);
+
+		/* reset dma engine again */
+		out_le32(&pi->dbdma->control,
+			 0 | (RUN | PAUSE | FLUSH | WAKE) << 16);
+		timeout = 100;
+		while (in_le32(&pi->dbdma->status) & RUN && timeout--)
+			udelay(1);
+		if (timeout <= 0) {
+			printk(KERN_ERR
+			       "i2sbus: error waiting for dma reset\n");
+			result = -ENXIO;
+			goto out_unlock;
+		}
+
+		/* wake up the chip with the next descriptor */
+		out_le32(&pi->dbdma->control,
+			 (RUN | WAKE) | ((RUN | WAKE) << 16));
+		/* get the frame count  */
+		pi->frame_count = in_le32(&i2sdev->intfregs->frame_count);
+
+		/* off you go! */
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+		if (!pi->dbdma_ring.running) {
+			result = -EALREADY;
+			goto out_unlock;
+		}
+
+		/* turn off all relevant bits */
+		out_le32(&pi->dbdma->control,
+			 (RUN | WAKE | FLUSH | PAUSE) << 16);
+		{
+			/* FIXME: move to own function */
+			int timeout = 5000;
+			while ((in_le32(&pi->dbdma->status) & RUN)
+			       && --timeout > 0)
+				udelay(1);
+			if (!timeout)
+				printk(KERN_ERR
+				       "i2sbus: timed out turning "
+				       "off dbdma engine!\n");
+		}
+
+		pi->dbdma_ring.running = 0;
+		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;
+
+	return (bytes_to_frames(pi->substream->runtime,
+			pi->current_period *
+			snd_pcm_lib_period_bytes(pi->substream))
+		+ fc) % pi->substream->runtime->buffer_size;
+}
+
+static inline void handle_interrupt(struct i2sbus_dev *i2sdev, int in)
+{
+	struct pcm_info *pi;
+	u32 fc;
+	u32 delta;
+
+	spin_lock(&i2sdev->low_lock);
+	get_pcm_info(i2sdev, in, &pi, NULL);
+
+	if (!pi->dbdma_ring.running) {
+		/* there was still an interrupt pending
+		 * while we stopped. or maybe another
+		 * processor (not the one that was stopping
+		 * the DMA engine) was spinning above
+		 * waiting for the lock. */
+		goto out_unlock;
+	}
+
+	fc = in_le32(&i2sdev->intfregs->frame_count);
+	/* a counter overflow does not change the calculation. */
+	delta = fc - pi->frame_count;
+
+	/* update current_period */
+	while (delta >= pi->substream->runtime->period_size) {
+		pi->current_period++;
+		delta = delta - pi->substream->runtime->period_size;
+	}
+
+	if (unlikely(delta)) {
+		/* Some interrupt came late, so check the dbdma.
+		 * This special case exists to syncronize the frame_count with
+		 * the dbdma transfer, but is hit every once in a while. */
+		int period;
+
+		period = (in_le32(&pi->dbdma->cmdptr)
+		        - pi->dbdma_ring.bus_cmd_start)
+				/ sizeof(struct dbdma_cmd);
+		pi->current_period = pi->current_period
+					% pi->substream->runtime->periods;
+
+		while (pi->current_period != period) {
+			pi->current_period++;
+			pi->current_period %= pi->substream->runtime->periods;
+			/* Set delta to zero, as the frame_count value is too
+			 * high (otherwise the code path will not be executed).
+			 * This corrects the fact that the frame_count is too
+			 * low at the beginning due to buffering. */
+			delta = 0;
+		}
+	}
+
+	pi->frame_count = fc - delta;
+	pi->current_period %= pi->substream->runtime->periods;
+
+	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, struct pt_regs *regs)
+{
+	handle_interrupt((struct i2sbus_dev *)devid, 0);
+	return IRQ_HANDLED;
+}
+
+irqreturn_t i2sbus_rx_intr(int irq, void *devid, struct pt_regs * regs)
+{
+	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_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_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);
+}
+
+/* FIXME: this function needs an error handling strategy with labels */
+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");
+		kfree(cii);
+		return -ENODEV;
+	}
+
+	if (!try_module_get(THIS_MODULE)) {
+		printk(KERN_DEBUG "i2sbus: failed to get module reference!\n");
+		soundbus_dev_put(dev);
+		kfree(cii);
+		return -EBUSY;
+	}
+
+	if (!try_module_get(ci->owner)) {
+		printk(KERN_DEBUG
+		       "i2sbus: failed to get module reference to codec owner!\n");
+		module_put(THIS_MODULE);
+		soundbus_dev_put(dev);
+		kfree(cii);
+		return -EBUSY;
+	}
+
+	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");
+			kfree(cii);
+			module_put(ci->owner);
+			soundbus_dev_put(dev);
+			module_put(THIS_MODULE);
+			return err;
+		}
+	}
+
+	/* 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");
+			module_put(ci->owner);
+			kfree(cii);
+			soundbus_dev_put(dev);
+			module_put(THIS_MODULE);
+			return -EINVAL;
+		}
+		if ((err =
+		     snd_pcm_new_stream(dev->pcm, SNDRV_PCM_STREAM_PLAYBACK, 1))) {
+			module_put(ci->owner);
+			kfree(cii);
+			soundbus_dev_put(dev);
+			module_put(THIS_MODULE);
+			return err;
+		}
+		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");
+			module_put(ci->owner);
+			kfree(cii);
+			soundbus_dev_put(dev);
+			module_put(THIS_MODULE);
+			return -EINVAL;
+		}
+		if ((err =
+		     snd_pcm_new_stream(dev->pcm, SNDRV_PCM_STREAM_CAPTURE, 1))) {
+			module_put(ci->owner);
+			kfree(cii);
+			soundbus_dev_put(dev);
+			module_put(THIS_MODULE);
+			return err;
+		}
+		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");
+		module_put(ci->owner);
+		kfree(cii);
+		soundbus_dev_put(dev);
+		module_put(THIS_MODULE);
+		return err;
+	}
+	/* 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;
+}
+
+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);
+	}
+}