[PATCH] dmaengine: axi-dmac: simple device_config operation implemented

[Alexandru Ardelean]

From: Rodrigo Alencar <alencar.fmce@xxxxxxxxxxxx>

dmaengine_slave_config is called by dmaengine_pcm_hw_params when using
axi-i2s with axi-dmac. If device_config is NULL, -ENOSYS  is returned,
which breaks the snd_pcm_hw_params function.
This is a fix for the error:

$ aplay -D plughw:ADAU1761 /usr/share/sounds/alsa/Front_Center.wav
Playing WAVE '/usr/share/sounds/alsa/Front_Center.wav' : Signed 16 bit
Little Endian, Rate 48000 Hz, Mono
axi-i2s 43c20000.axi-i2s: ASoC: 43c20000.axi-i2s hw params failed: -38
aplay: set_params:1403: Unable to install hw params:
ACCESS:  RW_INTERLEAVED
FORMAT:  S16_LE
SUBFORMAT:  STD
SAMPLE_BITS: 16
FRAME_BITS: 16
CHANNELS: 1
RATE: 48000
PERIOD_TIME: 125000
PERIOD_SIZE: 6000
PERIOD_BYTES: 12000
PERIODS: 4
BUFFER_TIME: 500000
BUFFER_SIZE: 24000
BUFFER_BYTES: 48000
TICK_TIME: 0

Signed-off-by: Rodrigo Alencar <alencar.fmce@xxxxxxxxxxxx>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---

Note: Fixes tag not added intentionally.

 drivers/dma/dma-axi-dmac.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index a0ee404b736e..ab2677343202 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -564,6 +564,21 @@ static struct dma_async_tx_descriptor *axi_dmac_prep_slave_sg(
 	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 }
 
+static int axi_dmac_device_config(struct dma_chan *c,
+			struct dma_slave_config *slave_config)
+{
+	struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
+	struct axi_dmac *dmac = chan_to_axi_dmac(chan);
+
+	/* no configuration required, a sanity check is done instead */
+	if (slave_config->direction != chan->direction) {
+		dev_err(dmac->dma_dev.dev, "Direction not supported by this DMA Channel");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static struct dma_async_tx_descriptor *axi_dmac_prep_dma_cyclic(
 	struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
 	size_t period_len, enum dma_transfer_direction direction,
@@ -878,6 +893,7 @@ static int axi_dmac_probe(struct platform_device *pdev)
 	dma_dev->device_tx_status = dma_cookie_status;
 	dma_dev->device_issue_pending = axi_dmac_issue_pending;
 	dma_dev->device_prep_slave_sg = axi_dmac_prep_slave_sg;
+	dma_dev->device_config = axi_dmac_device_config;
 	dma_dev->device_prep_dma_cyclic = axi_dmac_prep_dma_cyclic;
 	dma_dev->device_prep_interleaved_dma = axi_dmac_prep_interleaved;
 	dma_dev->device_terminate_all = axi_dmac_terminate_all;
-- 
2.20.1