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-rw-r--r--sound/soc/atmel/atmel-pcm-dma.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/sound/soc/atmel/atmel-pcm-dma.c b/sound/soc/atmel/atmel-pcm-dma.c
new file mode 100644
index 000000000..96a8c7dba
--- /dev/null
+++ b/sound/soc/atmel/atmel-pcm-dma.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * atmel-pcm-dma.c -- ALSA PCM DMA support for the Atmel SoC.
+ *
+ * Copyright (C) 2012 Atmel
+ *
+ * Author: Bo Shen <voice.shen@atmel.com>
+ *
+ * Based on atmel-pcm by:
+ * Sedji Gaouaou <sedji.gaouaou@atmel.com>
+ * Copyright 2008 Atmel
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/atmel-ssc.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/dmaengine_pcm.h>
+
+#include "atmel-pcm.h"
+
+/*--------------------------------------------------------------------------*\
+ * Hardware definition
+\*--------------------------------------------------------------------------*/
+static const struct snd_pcm_hardware atmel_pcm_dma_hardware = {
+ .info = SNDRV_PCM_INFO_MMAP |
+ SNDRV_PCM_INFO_MMAP_VALID |
+ SNDRV_PCM_INFO_INTERLEAVED |
+ SNDRV_PCM_INFO_RESUME |
+ SNDRV_PCM_INFO_PAUSE,
+ .period_bytes_min = 256, /* lighting DMA overhead */
+ .period_bytes_max = 2 * 0xffff, /* if 2 bytes format */
+ .periods_min = 8,
+ .periods_max = 1024, /* no limit */
+ .buffer_bytes_max = 512 * 1024,
+};
+
+/*
+ * atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC
+ *
+ * We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
+ * check if any overrun occured.
+ */
+static void atmel_pcm_dma_irq(u32 ssc_sr,
+ struct snd_pcm_substream *substream)
+{
+ struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+ struct atmel_pcm_dma_params *prtd;
+
+ prtd = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
+
+ if (ssc_sr & prtd->mask->ssc_error) {
+ if (snd_pcm_running(substream))
+ pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x)\n",
+ substream->stream == SNDRV_PCM_STREAM_PLAYBACK
+ ? "underrun" : "overrun", prtd->name,
+ ssc_sr);
+
+ /* stop RX and capture: will be enabled again at restart */
+ ssc_writex(prtd->ssc->regs, SSC_CR, prtd->mask->ssc_disable);
+ snd_pcm_stop_xrun(substream);
+
+ /* now drain RHR and read status to remove xrun condition */
+ ssc_readx(prtd->ssc->regs, SSC_RHR);
+ ssc_readx(prtd->ssc->regs, SSC_SR);
+ }
+}
+
+static int atmel_pcm_configure_dma(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
+{
+ struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+ struct atmel_pcm_dma_params *prtd;
+ struct ssc_device *ssc;
+ int ret;
+
+ prtd = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
+ ssc = prtd->ssc;
+
+ ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
+ if (ret) {
+ pr_err("atmel-pcm: hwparams to dma slave configure failed\n");
+ return ret;
+ }
+
+ slave_config->dst_addr = ssc->phybase + SSC_THR;
+ slave_config->dst_maxburst = 1;
+
+ slave_config->src_addr = ssc->phybase + SSC_RHR;
+ slave_config->src_maxburst = 1;
+
+ prtd->dma_intr_handler = atmel_pcm_dma_irq;
+
+ return 0;
+}
+
+static const struct snd_dmaengine_pcm_config atmel_dmaengine_pcm_config = {
+ .prepare_slave_config = atmel_pcm_configure_dma,
+ .pcm_hardware = &atmel_pcm_dma_hardware,
+ .prealloc_buffer_size = 64 * 1024,
+};
+
+int atmel_pcm_dma_platform_register(struct device *dev)
+{
+ return devm_snd_dmaengine_pcm_register(dev,
+ &atmel_dmaengine_pcm_config, 0);
+}
+EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
+
+MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
+MODULE_DESCRIPTION("Atmel DMA based PCM module");
+MODULE_LICENSE("GPL");