ASoC: wm_adsp: Add a handler for the compressed IRQ

Here support is added for responding to DSP IRQs that are used to
indicate data being available on the DSP. The idea is that we check the
amount of data available upon receipt of an IRQ and on subsequent calls
to the pointer callback we recheck once less than one fragment is
available (to avoid excessive SPI traffic), if there is truely less than
one fragment available we ack the last IRQ and wait for a new one.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 188 insertions, 0 deletions

diff --git a/sound/soc/codecs/wm_adsp.c b/sound/soc/codecs/wm_adsp.c
index ac879d16c6a6..49ef0bbe9892 100644
--- a/sound/soc/codecs/wm_adsp.c
+++ b/sound/soc/codecs/wm_adsp.c
@@ -279,6 +279,11 @@ struct wm_adsp_compr_buf {
 
 	struct wm_adsp_buffer_region *regions;
 	u32 host_buf_ptr;
+
+	u32 error;
+	u32 irq_count;
+	int read_index;
+	int avail;
 };
 
 struct wm_adsp_compr {
@@ -287,6 +292,8 @@ struct wm_adsp_compr {
 
 	struct snd_compr_stream *stream;
 	struct snd_compressed_buffer size;
+
+	unsigned int copied_total;
 };
 
 #define WM_ADSP_DATA_WORD_SIZE         3
@@ -2436,6 +2443,11 @@ static int wm_adsp_compr_check_params(struct snd_compr_stream *stream,
 	return -EINVAL;
 }
 
+static inline unsigned int wm_adsp_compr_frag_words(struct wm_adsp_compr *compr)
+{
+	return compr->size.fragment_size / WM_ADSP_DATA_WORD_SIZE;
+}
+
 int wm_adsp_compr_set_params(struct snd_compr_stream *stream,
 			     struct snd_compr_params *params)
 {
@@ -2622,6 +2634,8 @@ static int wm_adsp_buffer_init(struct wm_adsp *dsp)
 		return -ENOMEM;
 
 	buf->dsp = dsp;
+	buf->read_index = -1;
+	buf->irq_count = 0xFFFFFFFF;
 
 	ret = wm_adsp_buffer_locate(buf);
 	if (ret < 0) {
@@ -2705,6 +2719,16 @@ int wm_adsp_compr_trigger(struct snd_compr_stream *stream, int cmd)
 				 ret);
 			break;
 		}
+
+		/* Trigger the IRQ at one fragment of data */
+		ret = wm_adsp_buffer_write(compr->buf,
+					   HOST_BUFFER_FIELD(high_water_mark),
+					   wm_adsp_compr_frag_words(compr));
+		if (ret < 0) {
+			adsp_err(dsp, "Failed to set high water mark: %d\n",
+				 ret);
+			break;
+		}
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
 		break;
@@ -2719,4 +2743,168 @@ int wm_adsp_compr_trigger(struct snd_compr_stream *stream, int cmd)
 }
 EXPORT_SYMBOL_GPL(wm_adsp_compr_trigger);
 
+static inline int wm_adsp_buffer_size(struct wm_adsp_compr_buf *buf)
+{
+	int last_region = wm_adsp_fw[buf->dsp->fw].caps->num_regions - 1;
+
+	return buf->regions[last_region].cumulative_size;
+}
+
+static int wm_adsp_buffer_update_avail(struct wm_adsp_compr_buf *buf)
+{
+	u32 next_read_index, next_write_index;
+	int write_index, read_index, avail;
+	int ret;
+
+	/* Only sync read index if we haven't already read a valid index */
+	if (buf->read_index < 0) {
+		ret = wm_adsp_buffer_read(buf,
+				HOST_BUFFER_FIELD(next_read_index),
+				&next_read_index);
+		if (ret < 0)
+			return ret;
+
+		read_index = sign_extend32(next_read_index, 23);
+
+		if (read_index < 0) {
+			adsp_dbg(buf->dsp, "Avail check on unstarted stream\n");
+			return 0;
+		}
+
+		buf->read_index = read_index;
+	}
+
+	ret = wm_adsp_buffer_read(buf, HOST_BUFFER_FIELD(next_write_index),
+			&next_write_index);
+	if (ret < 0)
+		return ret;
+
+	write_index = sign_extend32(next_write_index, 23);
+
+	avail = write_index - buf->read_index;
+	if (avail < 0)
+		avail += wm_adsp_buffer_size(buf);
+
+	adsp_dbg(buf->dsp, "readindex=0x%x, writeindex=0x%x, avail=%d\n",
+		 buf->read_index, write_index, avail);
+
+	buf->avail = avail;
+
+	return 0;
+}
+
+int wm_adsp_compr_handle_irq(struct wm_adsp *dsp)
+{
+	struct wm_adsp_compr_buf *buf = dsp->buffer;
+	int ret = 0;
+
+	mutex_lock(&dsp->pwr_lock);
+
+	if (!buf) {
+		adsp_err(dsp, "Spurious buffer IRQ\n");
+		ret = -ENODEV;
+		goto out;
+	}
+
+	adsp_dbg(dsp, "Handling buffer IRQ\n");
+
+	ret = wm_adsp_buffer_read(buf, HOST_BUFFER_FIELD(error), &buf->error);
+	if (ret < 0) {
+		adsp_err(dsp, "Failed to check buffer error: %d\n", ret);
+		goto out;
+	}
+	if (buf->error != 0) {
+		adsp_err(dsp, "Buffer error occurred: %d\n", buf->error);
+		ret = -EIO;
+		goto out;
+	}
+
+	ret = wm_adsp_buffer_read(buf, HOST_BUFFER_FIELD(irq_count),
+				  &buf->irq_count);
+	if (ret < 0) {
+		adsp_err(dsp, "Failed to get irq_count: %d\n", ret);
+		goto out;
+	}
+
+	ret = wm_adsp_buffer_update_avail(buf);
+	if (ret < 0) {
+		adsp_err(dsp, "Error reading avail: %d\n", ret);
+		goto out;
+	}
+
+out:
+	mutex_unlock(&dsp->pwr_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(wm_adsp_compr_handle_irq);
+
+static int wm_adsp_buffer_reenable_irq(struct wm_adsp_compr_buf *buf)
+{
+	if (buf->irq_count & 0x01)
+		return 0;
+
+	adsp_dbg(buf->dsp, "Enable IRQ(0x%x) for next fragment\n",
+		 buf->irq_count);
+
+	buf->irq_count |= 0x01;
+
+	return wm_adsp_buffer_write(buf, HOST_BUFFER_FIELD(irq_ack),
+				    buf->irq_count);
+}
+
+int wm_adsp_compr_pointer(struct snd_compr_stream *stream,
+			  struct snd_compr_tstamp *tstamp)
+{
+	struct wm_adsp_compr *compr = stream->runtime->private_data;
+	struct wm_adsp_compr_buf *buf = compr->buf;
+	struct wm_adsp *dsp = compr->dsp;
+	int ret = 0;
+
+	adsp_dbg(dsp, "Pointer request\n");
+
+	mutex_lock(&dsp->pwr_lock);
+
+	if (!compr->buf) {
+		ret = -ENXIO;
+		goto out;
+	}
+
+	if (compr->buf->error) {
+		ret = -EIO;
+		goto out;
+	}
+
+	if (buf->avail < wm_adsp_compr_frag_words(compr)) {
+		ret = wm_adsp_buffer_update_avail(buf);
+		if (ret < 0) {
+			adsp_err(dsp, "Error reading avail: %d\n", ret);
+			goto out;
+		}
+
+		/*
+		 * If we really have less than 1 fragment available tell the
+		 * DSP to inform us once a whole fragment is available.
+		 */
+		if (buf->avail < wm_adsp_compr_frag_words(compr)) {
+			ret = wm_adsp_buffer_reenable_irq(buf);
+			if (ret < 0) {
+				adsp_err(dsp,
+					 "Failed to re-enable buffer IRQ: %d\n",
+					 ret);
+				goto out;
+			}
+		}
+	}
+
+	tstamp->copied_total = compr->copied_total;
+	tstamp->copied_total += buf->avail * WM_ADSP_DATA_WORD_SIZE;
+
+out:
+	mutex_unlock(&dsp->pwr_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(wm_adsp_compr_pointer);
+
 MODULE_LICENSE("GPL v2");