ASoC: dwc: Disallow building designware_pcm as a module

Designware PCM is an extension to Designware I2S and they are dependent
on each other. For this reason, make Designware PCM a boolean which will
compile with Desigwnare I2S module. The name of the module is not changed
but the name of the files need to be changed.

Also, without this commit we get errors when probbing designware_i2s module
because of unspecified license:

designware_pcm: module license 'unspecified' taints kernel.
Disabling lock debugging due to kernel taint
designware_pcm: Unknown symbol __rcu_read_lock (err 0)
designware_pcm: Unknown symbol devm_snd_soc_register_platform (err 0)
designware_pcm: Unknown symbol synchronize_rcu (err 0)
designware_pcm: Unknown symbol __rcu_read_unlock (err 0)
designware_pcm: Unknown symbol snd_soc_set_runtime_hwparams (err 0)

So, this is really needed as a fix.

Fixes: 79361b2b98b7 ("ASoC: dwc: Add PIO PCM extension")
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 281 insertions, 0 deletions

diff --git a/sound/soc/dwc/dwc-pcm.c b/sound/soc/dwc/dwc-pcm.c
new file mode 100644
index 000000000000..406fd867117b
--- /dev/null
+++ b/sound/soc/dwc/dwc-pcm.c
@@ -0,0 +1,281 @@
+/*
+ * ALSA SoC Synopsys PIO PCM for I2S driver
+ *
+ * sound/soc/dwc/designware_pcm.c
+ *
+ * Copyright (C) 2016 Synopsys
+ * Jose Abreu <joabreu@synopsys.com>
+ *
+ * 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.
+ */
+
+#include <linux/io.h>
+#include <linux/rcupdate.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include "local.h"
+
+#define BUFFER_BYTES_MAX	(3 * 2 * 8 * PERIOD_BYTES_MIN)
+#define PERIOD_BYTES_MIN	4096
+#define PERIODS_MIN		2
+
+#define dw_pcm_tx_fn(sample_bits) \
+static unsigned int dw_pcm_tx_##sample_bits(struct dw_i2s_dev *dev, \
+		struct snd_pcm_runtime *runtime, unsigned int tx_ptr, \
+		bool *period_elapsed) \
+{ \
+	const u##sample_bits (*p)[2] = (void *)runtime->dma_area; \
+	unsigned int period_pos = tx_ptr % runtime->period_size; \
+	int i; \
+\
+	for (i = 0; i < dev->fifo_th; i++) { \
+		iowrite32(p[tx_ptr][0], dev->i2s_base + LRBR_LTHR(0)); \
+		iowrite32(p[tx_ptr][1], dev->i2s_base + RRBR_RTHR(0)); \
+		period_pos++; \
+		if (++tx_ptr >= runtime->buffer_size) \
+			tx_ptr = 0; \
+	} \
+	*period_elapsed = period_pos >= runtime->period_size; \
+	return tx_ptr; \
+}
+
+#define dw_pcm_rx_fn(sample_bits) \
+static unsigned int dw_pcm_rx_##sample_bits(struct dw_i2s_dev *dev, \
+		struct snd_pcm_runtime *runtime, unsigned int rx_ptr, \
+		bool *period_elapsed) \
+{ \
+	u##sample_bits (*p)[2] = (void *)runtime->dma_area; \
+	unsigned int period_pos = rx_ptr % runtime->period_size; \
+	int i; \
+\
+	for (i = 0; i < dev->fifo_th; i++) { \
+		p[rx_ptr][0] = ioread32(dev->i2s_base + LRBR_LTHR(0)); \
+		p[rx_ptr][1] = ioread32(dev->i2s_base + RRBR_RTHR(0)); \
+		period_pos++; \
+		if (++rx_ptr >= runtime->buffer_size) \
+			rx_ptr = 0; \
+	} \
+	*period_elapsed = period_pos >= runtime->period_size; \
+	return rx_ptr; \
+}
+
+dw_pcm_tx_fn(16);
+dw_pcm_tx_fn(32);
+dw_pcm_rx_fn(16);
+dw_pcm_rx_fn(32);
+
+#undef dw_pcm_tx_fn
+#undef dw_pcm_rx_fn
+
+static const struct snd_pcm_hardware dw_pcm_hardware = {
+	.info = SNDRV_PCM_INFO_INTERLEAVED |
+		SNDRV_PCM_INFO_MMAP |
+		SNDRV_PCM_INFO_MMAP_VALID |
+		SNDRV_PCM_INFO_BLOCK_TRANSFER,
+	.rates = SNDRV_PCM_RATE_32000 |
+		SNDRV_PCM_RATE_44100 |
+		SNDRV_PCM_RATE_48000,
+	.rate_min = 32000,
+	.rate_max = 48000,
+	.formats = SNDRV_PCM_FMTBIT_S16_LE |
+		SNDRV_PCM_FMTBIT_S24_LE |
+		SNDRV_PCM_FMTBIT_S32_LE,
+	.channels_min = 2,
+	.channels_max = 2,
+	.buffer_bytes_max = BUFFER_BYTES_MAX,
+	.period_bytes_min = PERIOD_BYTES_MIN,
+	.period_bytes_max = BUFFER_BYTES_MAX / PERIODS_MIN,
+	.periods_min = PERIODS_MIN,
+	.periods_max = BUFFER_BYTES_MAX / PERIOD_BYTES_MIN,
+	.fifo_size = 16,
+};
+
+static void dw_pcm_transfer(struct dw_i2s_dev *dev, bool push)
+{
+	struct snd_pcm_substream *substream;
+	bool active, period_elapsed;
+
+	rcu_read_lock();
+	if (push)
+		substream = rcu_dereference(dev->tx_substream);
+	else
+		substream = rcu_dereference(dev->rx_substream);
+	active = substream && snd_pcm_running(substream);
+	if (active) {
+		unsigned int ptr;
+		unsigned int new_ptr;
+
+		if (push) {
+			ptr = READ_ONCE(dev->tx_ptr);
+			new_ptr = dev->tx_fn(dev, substream->runtime, ptr,
+					&period_elapsed);
+			cmpxchg(&dev->tx_ptr, ptr, new_ptr);
+		} else {
+			ptr = READ_ONCE(dev->rx_ptr);
+			new_ptr = dev->rx_fn(dev, substream->runtime, ptr,
+					&period_elapsed);
+			cmpxchg(&dev->rx_ptr, ptr, new_ptr);
+		}
+
+		if (period_elapsed)
+			snd_pcm_period_elapsed(substream);
+	}
+	rcu_read_unlock();
+}
+
+void dw_pcm_push_tx(struct dw_i2s_dev *dev)
+{
+	dw_pcm_transfer(dev, true);
+}
+
+void dw_pcm_pop_rx(struct dw_i2s_dev *dev)
+{
+	dw_pcm_transfer(dev, false);
+}
+
+static int dw_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct dw_i2s_dev *dev = snd_soc_dai_get_drvdata(rtd->cpu_dai);
+
+	snd_soc_set_runtime_hwparams(substream, &dw_pcm_hardware);
+	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
+	runtime->private_data = dev;
+
+	return 0;
+}
+
+static int dw_pcm_close(struct snd_pcm_substream *substream)
+{
+	synchronize_rcu();
+	return 0;
+}
+
+static int dw_pcm_hw_params(struct snd_pcm_substream *substream,
+		struct snd_pcm_hw_params *hw_params)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct dw_i2s_dev *dev = runtime->private_data;
+	int ret;
+
+	switch (params_channels(hw_params)) {
+	case 2:
+		break;
+	default:
+		dev_err(dev->dev, "invalid channels number\n");
+		return -EINVAL;
+	}
+
+	switch (params_format(hw_params)) {
+	case SNDRV_PCM_FORMAT_S16_LE:
+		dev->tx_fn = dw_pcm_tx_16;
+		dev->rx_fn = dw_pcm_rx_16;
+		break;
+	case SNDRV_PCM_FORMAT_S24_LE:
+	case SNDRV_PCM_FORMAT_S32_LE:
+		dev->tx_fn = dw_pcm_tx_32;
+		dev->rx_fn = dw_pcm_rx_32;
+		break;
+	default:
+		dev_err(dev->dev, "invalid format\n");
+		return -EINVAL;
+	}
+
+	ret = snd_pcm_lib_malloc_pages(substream,
+			params_buffer_bytes(hw_params));
+	if (ret < 0)
+		return ret;
+	else
+		return 0;
+}
+
+static int dw_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	return snd_pcm_lib_free_pages(substream);
+}
+
+static int dw_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct dw_i2s_dev *dev = runtime->private_data;
+	int ret = 0;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+			WRITE_ONCE(dev->tx_ptr, 0);
+			rcu_assign_pointer(dev->tx_substream, substream);
+		} else {
+			WRITE_ONCE(dev->rx_ptr, 0);
+			rcu_assign_pointer(dev->rx_substream, substream);
+		}
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+			rcu_assign_pointer(dev->tx_substream, NULL);
+		else
+			rcu_assign_pointer(dev->rx_substream, NULL);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static snd_pcm_uframes_t dw_pcm_pointer(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct dw_i2s_dev *dev = runtime->private_data;
+	snd_pcm_uframes_t pos;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		pos = READ_ONCE(dev->tx_ptr);
+	else
+		pos = READ_ONCE(dev->rx_ptr);
+
+	return pos < runtime->buffer_size ? pos : 0;
+}
+
+static int dw_pcm_new(struct snd_soc_pcm_runtime *rtd)
+{
+	size_t size = dw_pcm_hardware.buffer_bytes_max;
+
+	return snd_pcm_lib_preallocate_pages_for_all(rtd->pcm,
+			SNDRV_DMA_TYPE_CONTINUOUS,
+			snd_dma_continuous_data(GFP_KERNEL), size, size);
+}
+
+static void dw_pcm_free(struct snd_pcm *pcm)
+{
+	snd_pcm_lib_preallocate_free_for_all(pcm);
+}
+
+static const struct snd_pcm_ops dw_pcm_ops = {
+	.open = dw_pcm_open,
+	.close = dw_pcm_close,
+	.ioctl = snd_pcm_lib_ioctl,
+	.hw_params = dw_pcm_hw_params,
+	.hw_free = dw_pcm_hw_free,
+	.trigger = dw_pcm_trigger,
+	.pointer = dw_pcm_pointer,
+};
+
+static const struct snd_soc_platform_driver dw_pcm_platform = {
+	.pcm_new = dw_pcm_new,
+	.pcm_free = dw_pcm_free,
+	.ops = &dw_pcm_ops,
+};
+
+int dw_pcm_register(struct platform_device *pdev)
+{
+	return devm_snd_soc_register_platform(&pdev->dev, &dw_pcm_platform);
+}