@@ -47,6 +47,10 @@ Optional properties:
- codec-handle: Phandle to a 'codec' node that defines an audio
codec connected to this SSI. This node is typically
a child of an I2C or other control node.
+- fsl,fiq-stream-filter: Bool property. Disabled DMA and use FIQ instead to
+ filter the codec stream. This is necessary for some boards
+ where an incompatible codec is connected to this SSI, e.g.
+ on pca100 and pcm043.
Child 'codec' node required properties:
- compatible: Compatible list, contains the name of the codec
@@ -8,6 +8,26 @@
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
+ *
+ *
+ * Some notes why imx-pcm-fiq is used instead of DMA on some boards:
+ *
+ * The i.MX SSI core has some nasty limitations in AC97 mode. While most
+ * sane processor vendors have a FIFO per AC97 slot, the i.MX has only
+ * one FIFO which combines all valid receive slots. We cannot even select
+ * which slots we want to receive. The WM9712 with which this driver
+ * was developed with always sends GPIO status data in slot 12 which
+ * we receive in our (PCM-) data stream. The only chance we have is to
+ * manually skip this data in the FIQ handler. With sampling rates different
+ * from 48000Hz not every frame has valid receive data, so the ratio
+ * between pcm data and GPIO status data changes. Our FIQ handler is not
+ * able to handle this, hence this driver only works with 48000Hz sampling
+ * rate.
+ * Reading and writing AC97 registers is another challenge. The core
+ * provides us status bits when the read register is updated with *another*
+ * value. When we read the same register two times (and the register still
+ * contains the same value) these status bits are not set. We work
+ * around this by not polling these bits but only wait a fixed delay.
*/
#include <linux/init.h>
@@ -121,11 +141,13 @@ struct fsl_ssi_private {
bool new_binding;
bool ssi_on_imx;
+ bool use_dma;
struct clk *clk;
struct snd_dmaengine_dai_dma_data dma_params_tx;
struct snd_dmaengine_dai_dma_data dma_params_rx;
struct imx_dma_data filter_data_tx;
struct imx_dma_data filter_data_rx;
+ struct imx_pcm_fiq_params fiq_params;
struct {
unsigned int rfrc;
@@ -355,7 +377,12 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
*/
/* Enable the interrupts and DMA requests */
- write_ssi(SIER_FLAGS, &ssi->sier);
+ if (ssi_private->use_dma)
+ write_ssi(SIER_FLAGS, &ssi->sier);
+ else
+ write_ssi(CCSR_SSI_SIER_TIE | CCSR_SSI_SIER_TFE0_EN |
+ CCSR_SSI_SIER_RIE |
+ CCSR_SSI_SIER_RFF0_EN, &ssi->sier);
/*
* Set the watermark for transmit FIFI 0 and receive FIFO 0. We
@@ -543,7 +570,7 @@ static int fsl_ssi_dai_probe(struct snd_soc_dai *dai)
{
struct fsl_ssi_private *ssi_private = snd_soc_dai_get_drvdata(dai);
- if (ssi_private->ssi_on_imx) {
+ if (ssi_private->ssi_on_imx && ssi_private->use_dma) {
dai->playback_dma_data = &ssi_private->dma_params_tx;
dai->capture_dma_data = &ssi_private->dma_params_rx;
}
@@ -683,6 +710,9 @@ static int fsl_ssi_probe(struct platform_device *pdev)
strcpy(ssi_private->name, p);
+ ssi_private->use_dma = !of_property_read_bool(np,
+ "fsl,fiq-stream-filter");
+
/* Initialize this copy of the CPU DAI driver structure */
memcpy(&ssi_private->cpu_dai_drv, &fsl_ssi_dai_template,
sizeof(fsl_ssi_dai_template));
@@ -707,12 +737,16 @@ static int fsl_ssi_probe(struct platform_device *pdev)
return -ENXIO;
}
- /* The 'name' should not have any slashes in it. */
- ret = devm_request_irq(&pdev->dev, ssi_private->irq, fsl_ssi_isr, 0,
- ssi_private->name, ssi_private);
- if (ret < 0) {
- dev_err(&pdev->dev, "could not claim irq %u\n", ssi_private->irq);
- goto error_irqmap;
+ if (ssi_private->use_dma) {
+ /* The 'name' should not have any slashes in it. */
+ ret = devm_request_irq(&pdev->dev, ssi_private->irq,
+ fsl_ssi_isr, 0, ssi_private->name,
+ ssi_private);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "could not claim irq %u\n",
+ ssi_private->irq);
+ goto error_irqmap;
+ }
}
/* Are the RX and the TX clocks locked? */
@@ -766,7 +800,7 @@ static int fsl_ssi_probe(struct platform_device *pdev)
*/
ret = of_property_read_u32_array(pdev->dev.of_node,
"fsl,ssi-dma-events", dma_events, 2);
- if (ret) {
+ if (ret && !ssi_private->use_dma) {
dev_err(&pdev->dev, "could not get dma events\n");
goto error_clk;
}
@@ -805,9 +839,30 @@ static int fsl_ssi_probe(struct platform_device *pdev)
}
if (ssi_private->ssi_on_imx) {
- ret = imx_pcm_dma_init(pdev);
- if (ret)
- goto error_dev;
+ if (!ssi_private->use_dma) {
+
+ /*
+ * Some boards use an incompatible codec. To get it
+ * working, we are using imx-fiq-pcm-audio, that
+ * can handle those codecs. DMA is not possible in this
+ * situation.
+ */
+
+ ssi_private->fiq_params.irq = ssi_private->irq;
+ ssi_private->fiq_params.base = ssi_private->ssi;
+ ssi_private->fiq_params.dma_params_rx =
+ &ssi_private->dma_params_rx;
+ ssi_private->fiq_params.dma_params_tx =
+ &ssi_private->dma_params_tx;
+
+ ret = imx_pcm_fiq_init(pdev, &ssi_private->fiq_params);
+ if (ret)
+ goto error_dev;
+ } else {
+ ret = imx_pcm_dma_init(pdev);
+ if (ret)
+ goto error_dev;
+ }
}
/*