Re: [PATCH 1/2 v6] ASoC: dwc: Add custom PCM driver
From: Jose Abreu
Date: Fri Apr 29 2016 - 05:03:19 EST
Hi Mark,
Can you give me some comments regarding this patch? Am I following the right
track? This is the first time that I am using ALSA SoC so pardon me if I am
making some mistake. I would appreciate some kind of input. I tested this only
on a ARC SDP and it is working.
On 27-04-2016 11:05, Jose Abreu wrote:
> HDMI audio support was added to the AXS board using an
> I2S cpu driver and a custom platform driver.
>
> The platform driver supports two channels @ 16 bits with
> rates 32k, 44.1k and 48k.
>
> Although the mainline I2S driver uses ALSA DMA engine,
> this controller can be built without DMA support so it
> was necessary to add this custom platform driver so that
> HDMI audio works in AXS boards.
>
> The selection between the use of DMA engine or PIO mode
> is detected by declaring or not the DMA parameters in
> the device tree.
>
> Signed-off-by: Jose Abreu <joabreu@xxxxxxxxxxxx>
> Cc: Carlos Palminha <palminha@xxxxxxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
> Cc: Jaroslav Kysela <perex@xxxxxxxx>
> Cc: Takashi Iwai <tiwai@xxxxxxxx>
> Cc: Alexey Brodkin <abrodkin@xxxxxxxxxxxx>
> Cc: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
> Cc: alsa-devel@xxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> ---
>
> Changes v5 -> v6:
> * Use SNDRV_DMA_TYPE_CONTINUOUS
>
> Changes v4 -> v5:
> * Resolve undefined references when compiling as module
> * Use DMA properties in I2S to check which mode to use: PIO or DMA (as suggested by Lars-Peter Clausen)
>
> Changes v3 -> v4:
> * Reintroduced custom PCM driver
> * Use DT boolean to switch between ALSA DMA engine PCM or custom PCM
>
> Changes v2 -> v3:
> * Removed pll_config functions (as suggested by Alexey Brodkin)
> * Dropped custom platform driver, using now ALSA DMA engine
> * Dropped IRQ handler for I2S
>
> No changes v1 -> v2.
>
> sound/soc/dwc/Kconfig | 9 ++
> sound/soc/dwc/Makefile | 1 +
> sound/soc/dwc/designware.h | 71 +++++++++++++
> sound/soc/dwc/designware_i2s.c | 94 ++++++++++++-----
> sound/soc/dwc/designware_pcm.c | 228 +++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 376 insertions(+), 27 deletions(-)
> create mode 100644 sound/soc/dwc/designware.h
> create mode 100644 sound/soc/dwc/designware_pcm.c
>
> diff --git a/sound/soc/dwc/Kconfig b/sound/soc/dwc/Kconfig
> index d50e085..2a21120 100644
> --- a/sound/soc/dwc/Kconfig
> +++ b/sound/soc/dwc/Kconfig
> @@ -7,4 +7,13 @@ config SND_DESIGNWARE_I2S
> Synopsys desigwnware I2S device. The device supports upto
> maximum of 8 channels each for play and record.
>
> +config SND_DESIGNWARE_PCM
> + tristate "Synopsys I2S PCM Driver"
> + help
> + Say Y or M if you want to add support for ALSA ASoC platform driver
> + using I2S.
> +
> + Select this option if you want to be able to create a sound interface
> + using the I2S device driver as CPU driver. Instead of using ALSA
> + DMA engine by selecting this driver a custom PCM driver will be used.
>
> diff --git a/sound/soc/dwc/Makefile b/sound/soc/dwc/Makefile
> index 319371f..1b48bccc 100644
> --- a/sound/soc/dwc/Makefile
> +++ b/sound/soc/dwc/Makefile
> @@ -1,3 +1,4 @@
> # SYNOPSYS Platform Support
> obj-$(CONFIG_SND_DESIGNWARE_I2S) += designware_i2s.o
> +obj-$(CONFIG_SND_DESIGNWARE_PCM) += designware_pcm.o
>
> diff --git a/sound/soc/dwc/designware.h b/sound/soc/dwc/designware.h
> new file mode 100644
> index 0000000..09fafee
> --- /dev/null
> +++ b/sound/soc/dwc/designware.h
> @@ -0,0 +1,71 @@
> +/*
> + * ALSA SoC Synopsys Audio Layer
> + *
> + * sound/soc/dwc/designware.h
> + *
> + * Copyright (C) 2016 Synopsys
> + *
> + * 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.
> + */
> +
> +#ifndef __DESIGNWARE_H
> +#define __DESIGNWARE_H
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/kconfig.h>
> +#include <sound/designware_i2s.h>
> +#include <sound/dmaengine_pcm.h>
> +
> +struct dw_pcm_binfo {
> + struct snd_pcm_substream *stream;
> + unsigned char *dma_base;
> + unsigned char *dma_pointer;
> + unsigned int period_size_frames;
> + unsigned int size;
> + snd_pcm_uframes_t period_pointer;
> + unsigned int total_periods;
> + unsigned int current_period;
> +};
> +
> +union dw_i2s_snd_dma_data {
> + struct i2s_dma_data pd;
> + struct snd_dmaengine_dai_dma_data dt;
> +};
> +
> +struct dw_i2s_dev {
> + void __iomem *i2s_base;
> + struct clk *clk;
> + int active;
> + unsigned int capability;
> + unsigned int quirks;
> + unsigned int i2s_reg_comp1;
> + unsigned int i2s_reg_comp2;
> + struct device *dev;
> + u32 ccr;
> + u32 xfer_resolution;
> + u32 fifo_th;
> +
> + /* data related to DMA transfers b/w i2s and DMAC */
> + bool use_dmaengine;
> + union dw_i2s_snd_dma_data play_dma_data;
> + union dw_i2s_snd_dma_data capture_dma_data;
> + struct i2s_clk_config_data config;
> + int (*i2s_clk_cfg)(struct i2s_clk_config_data *config);
> + struct dw_pcm_binfo binfo;
> +};
> +
> +#if IS_ENABLED(CONFIG_SND_DESIGNWARE_PCM)
> +int dw_pcm_transfer(u32 *lsample, u32 *rsample, int bytes, int buf_size,
> + struct dw_pcm_binfo *bi);
> +#else
> +int dw_pcm_transfer(u32 *lsample, u32 *rsample, int bytes, int buf_size,
> + struct dw_pcm_binfo *bi)
> +{
> + return 0;
> +}
> +#endif
> +
> +#endif
> diff --git a/sound/soc/dwc/designware_i2s.c b/sound/soc/dwc/designware_i2s.c
> index 0db69b7..5ee0faf 100644
> --- a/sound/soc/dwc/designware_i2s.c
> +++ b/sound/soc/dwc/designware_i2s.c
> @@ -24,6 +24,7 @@
> #include <sound/pcm_params.h>
> #include <sound/soc.h>
> #include <sound/dmaengine_pcm.h>
> +#include "designware.h"
>
> /* common register for all channel */
> #define IER 0x000
> @@ -84,31 +85,6 @@
> #define MAX_CHANNEL_NUM 8
> #define MIN_CHANNEL_NUM 2
>
> -union dw_i2s_snd_dma_data {
> - struct i2s_dma_data pd;
> - struct snd_dmaengine_dai_dma_data dt;
> -};
> -
> -struct dw_i2s_dev {
> - void __iomem *i2s_base;
> - struct clk *clk;
> - int active;
> - unsigned int capability;
> - unsigned int quirks;
> - unsigned int i2s_reg_comp1;
> - unsigned int i2s_reg_comp2;
> - struct device *dev;
> - u32 ccr;
> - u32 xfer_resolution;
> - u32 fifo_th;
> -
> - /* data related to DMA transfers b/w i2s and DMAC */
> - union dw_i2s_snd_dma_data play_dma_data;
> - union dw_i2s_snd_dma_data capture_dma_data;
> - struct i2s_clk_config_data config;
> - int (*i2s_clk_cfg)(struct i2s_clk_config_data *config);
> -};
> -
> static inline void i2s_write_reg(void __iomem *io_base, int reg, u32 val)
> {
> writel(val, io_base + reg);
> @@ -145,6 +121,54 @@ static inline void i2s_clear_irqs(struct dw_i2s_dev *dev, u32 stream)
> }
> }
>
> +static irqreturn_t dw_i2s_irq_handler(int irq, void *dev_id)
> +{
> + struct dw_i2s_dev *dev = dev_id;
> + u32 isr[4], sleft[dev->fifo_th], sright[dev->fifo_th];
> + int i, j, xfer_bytes = dev->config.data_width / 8;
> + int dir = dev->binfo.stream->stream;
> +
> + for (i = 0; i < 4; i++)
> + isr[i] = i2s_read_reg(dev->i2s_base, ISR(i));
> +
> + i2s_clear_irqs(dev, SNDRV_PCM_STREAM_PLAYBACK);
> + i2s_clear_irqs(dev, SNDRV_PCM_STREAM_CAPTURE);
> +
> + if (dev->use_dmaengine)
> + return IRQ_HANDLED;
> +
> + for (i = 0; i < 4; i++) {
> + /* Copy only to/from first two channels
> + * TODO: Remaining channels
> + */
> + if ((isr[i] & 0x10) && (i == 0) &&
> + (dir == SNDRV_PCM_STREAM_PLAYBACK)) {
> + /* TXFEM - TX FIFO is empty */
> + dw_pcm_transfer(sleft, sright, xfer_bytes, dev->fifo_th,
> + &dev->binfo);
> + for (j = 0; j < dev->fifo_th; j++) {
> + i2s_write_reg(dev->i2s_base, LRBR_LTHR(i),
> + sleft[j]);
> + i2s_write_reg(dev->i2s_base, RRBR_RTHR(i),
> + sright[j]);
> + }
> + } else if ((isr[i] & 0x01) && (i == 0) &&
> + (dir == SNDRV_PCM_STREAM_CAPTURE)) {
> + /* RXDAM - RX FIFO is full */
> + for (j = 0; j < dev->fifo_th; j++) {
> + sleft[j] = i2s_read_reg(dev->i2s_base,
> + LRBR_LTHR(i));
> + sright[j] = i2s_read_reg(dev->i2s_base,
> + RRBR_RTHR(i));
> + }
> + dw_pcm_transfer(sleft, sright, xfer_bytes, dev->fifo_th,
> + &dev->binfo);
> + }
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> static void i2s_start(struct dw_i2s_dev *dev,
> struct snd_pcm_substream *substream)
> {
> @@ -626,7 +650,7 @@ static int dw_i2s_probe(struct platform_device *pdev)
> const struct i2s_platform_data *pdata = pdev->dev.platform_data;
> struct dw_i2s_dev *dev;
> struct resource *res;
> - int ret;
> + int ret, irq_number;
> struct snd_soc_dai_driver *dw_i2s_dai;
> const char *clk_id;
>
> @@ -649,6 +673,19 @@ static int dw_i2s_probe(struct platform_device *pdev)
> if (IS_ERR(dev->i2s_base))
> return PTR_ERR(dev->i2s_base);
>
> + irq_number = platform_get_irq(pdev, 0);
> + if (irq_number <= 0) {
> + dev_err(&pdev->dev, "get_irq fail\n");
> + return -EINVAL;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, irq_number, dw_i2s_irq_handler,
> + IRQF_SHARED, "dw_i2s_irq_handler", dev);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "request_irq fail\n");
> + return ret;
> + }
> +
> dev->dev = &pdev->dev;
>
> dev->i2s_reg_comp1 = I2S_COMP_PARAM_1;
> @@ -657,6 +694,7 @@ static int dw_i2s_probe(struct platform_device *pdev)
> dev->capability = pdata->cap;
> clk_id = NULL;
> dev->quirks = pdata->quirks;
> + dev->use_dmaengine = false;
> if (dev->quirks & DW_I2S_QUIRK_COMP_REG_OFFSET) {
> dev->i2s_reg_comp1 = pdata->i2s_reg_comp1;
> dev->i2s_reg_comp2 = pdata->i2s_reg_comp2;
> @@ -664,6 +702,8 @@ static int dw_i2s_probe(struct platform_device *pdev)
> ret = dw_configure_dai_by_pd(dev, dw_i2s_dai, res, pdata);
> } else {
> clk_id = "i2sclk";
> + dev->use_dmaengine = of_property_read_bool(pdev->dev.of_node,
> + "dmas");
> ret = dw_configure_dai_by_dt(dev, dw_i2s_dai, res);
> }
> if (ret < 0)
> @@ -695,7 +735,7 @@ static int dw_i2s_probe(struct platform_device *pdev)
> goto err_clk_disable;
> }
>
> - if (!pdata) {
> + if (dev->use_dmaengine) {
> ret = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, 0);
> if (ret) {
> dev_err(&pdev->dev,
> diff --git a/sound/soc/dwc/designware_pcm.c b/sound/soc/dwc/designware_pcm.c
> new file mode 100644
> index 0000000..beb4b99
> --- /dev/null
> +++ b/sound/soc/dwc/designware_pcm.c
> @@ -0,0 +1,228 @@
> +/*
> + * Synopsys I2S PCM Driver
> + *
> + * Copyright (C) 2016 Synopsys
> + *
> + * 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/module.h>
> +#include <linux/init.h>
> +#include <linux/platform_device.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/slab.h>
> +#include <sound/pcm.h>
> +#include <sound/soc.h>
> +#include <sound/dmaengine_pcm.h>
> +#include "designware.h"
> +
> +#define BUFFER_BYTES_MAX 384000
> +#define PERIOD_BYTES_MIN 2048
> +#define PERIODS_MIN 8
> +
> +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,
> + .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,
> +};
> +
> +int dw_pcm_transfer(u32 *lsample, u32 *rsample, int bytes, int buf_size,
> + struct dw_pcm_binfo *bi)
> +{
> + struct snd_pcm_runtime *rt = bi->stream->runtime;
> + int dir = bi->stream->stream;
> + int i;
> +
> + for (i = 0; i < buf_size; i++) {
> + if (dir == SNDRV_PCM_STREAM_PLAYBACK) {
> + memcpy(&lsample[i], bi->dma_pointer, bytes);
> + bi->dma_pointer += bytes;
> + memcpy(&rsample[i], bi->dma_pointer, bytes);
> + bi->dma_pointer += bytes;
> + } else {
> + memcpy(bi->dma_pointer, &lsample[i], bytes);
> + bi->dma_pointer += bytes;
> + memcpy(bi->dma_pointer, &rsample[i], bytes);
> + bi->dma_pointer += bytes;
> + }
> + }
> +
> + bi->period_pointer += bytes_to_frames(rt, bytes * 2 * buf_size);
> +
> + if (bi->period_pointer >= (bi->period_size_frames * bi->current_period)) {
> + bi->current_period++;
> + if (bi->current_period > bi->total_periods) {
> + bi->dma_pointer = bi->dma_base;
> + bi->period_pointer = 0;
> + bi->current_period = 1;
> + }
> + snd_pcm_period_elapsed(bi->stream);
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(dw_pcm_transfer);
> +
> +static int dw_pcm_open(struct snd_pcm_substream *substream)
> +{
> + struct snd_soc_pcm_runtime *rtd = substream->private_data;
> + struct snd_pcm_runtime *rt = substream->runtime;
> + 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(rt, SNDRV_PCM_HW_PARAM_PERIODS);
> +
> + dev->binfo.stream = substream;
> + rt->private_data = &dev->binfo;
> + return 0;
> +}
> +
> +static int dw_pcm_close(struct snd_pcm_substream *substream)
> +{
> + return 0;
> +}
> +
> +static int dw_pcm_hw_params(struct snd_pcm_substream *substream,
> + struct snd_pcm_hw_params *hw_params)
> +{
> + struct snd_pcm_runtime *rt = substream->runtime;
> + struct dw_pcm_binfo *bi = rt->private_data;
> + int ret;
> +
> + ret = snd_pcm_lib_alloc_vmalloc_buffer(substream,
> + params_buffer_bytes(hw_params));
> + if (ret < 0)
> + return ret;
> +
> + memset(rt->dma_area, 0, params_buffer_bytes(hw_params));
> + bi->dma_base = rt->dma_area;
> + bi->dma_pointer = bi->dma_base;
> +
> + return 0;
> +}
> +
> +static int dw_pcm_hw_free(struct snd_pcm_substream *substream)
> +{
> + return snd_pcm_lib_free_vmalloc_buffer(substream);
> +}
> +
> +static int dw_pcm_prepare(struct snd_pcm_substream *substream)
> +{
> + struct snd_pcm_runtime *rt = substream->runtime;
> + struct dw_pcm_binfo *bi = rt->private_data;
> + u32 buffer_size_frames = 0;
> +
> + bi->period_size_frames = bytes_to_frames(rt,
> + snd_pcm_lib_period_bytes(substream));
> + bi->size = snd_pcm_lib_buffer_bytes(substream);
> + buffer_size_frames = bytes_to_frames(rt, bi->size);
> + bi->total_periods = buffer_size_frames / bi->period_size_frames;
> + bi->current_period = 1;
> +
> + if ((buffer_size_frames % bi->period_size_frames) != 0)
> + return -EINVAL;
> + if ((bi->size % (snd_pcm_format_width(rt->format) / 8)) != 0)
> + return -EINVAL;
> + return 0;
> +}
> +
> +static int dw_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
> +{
> + switch (cmd) {
> + case SNDRV_PCM_TRIGGER_START:
> + case SNDRV_PCM_TRIGGER_RESUME:
> + break;
> + case SNDRV_PCM_TRIGGER_STOP:
> + case SNDRV_PCM_TRIGGER_SUSPEND:
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static snd_pcm_uframes_t dw_pcm_pointer(struct snd_pcm_substream *substream)
> +{
> + struct snd_pcm_runtime *rt = substream->runtime;
> + struct dw_pcm_binfo *bi = rt->private_data;
> +
> + return bi->period_pointer;
> +}
> +
> +static 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,
> + .prepare = dw_pcm_prepare,
> + .trigger = dw_pcm_trigger,
> + .pointer = dw_pcm_pointer,
> + .page = snd_pcm_lib_get_vmalloc_page,
> + .mmap = snd_pcm_lib_mmap_vmalloc,
> +};
> +
> +static int dw_pcm_new(struct snd_soc_pcm_runtime *runtime)
> +{
> + struct snd_pcm *pcm = runtime->pcm;
> +
> + return snd_pcm_lib_preallocate_pages_for_all(pcm,
> + SNDRV_DMA_TYPE_CONTINUOUS,
> + snd_dma_continuous_data(GFP_KERNEL), BUFFER_BYTES_MAX,
> + BUFFER_BYTES_MAX);
> +}
> +
> +static void dw_pcm_free(struct snd_pcm *pcm)
> +{
> + snd_pcm_lib_preallocate_free_for_all(pcm);
> +}
> +
> +static struct snd_soc_platform_driver dw_pcm_platform = {
> + .pcm_new = dw_pcm_new,
> + .pcm_free = dw_pcm_free,
> + .ops = &dw_pcm_ops,
> +};
> +
> +static int dw_pcm_probe(struct platform_device *pdev)
> +{
> + return devm_snd_soc_register_platform(&pdev->dev, &dw_pcm_platform);
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id dw_pcm_of[] = {
> + { .compatible = "snps,designware-pcm" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, dw_pcm_of);
> +#endif
> +
> +static struct platform_driver dw_pcm_driver = {
> + .driver = {
> + .name = "designware-pcm",
> + .of_match_table = of_match_ptr(dw_pcm_of),
> + },
> + .probe = dw_pcm_probe,
> +};
> +module_platform_driver(dw_pcm_driver);
> +
> +MODULE_AUTHOR("Jose Abreu <joabreu@xxxxxxxxxxxx>, Tiago Duarte");
> +MODULE_DESCRIPTION("Synopsys Designware PCM Driver");
> +MODULE_LICENSE("GPL v2");
Best regards,
Jose Miguel Abreu