Subject: Re: [PATCH v5 04/10] ASoC: qcom: Add lpass CPU driver for codec dma
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To:     Srinivasa Rao Mandadapu <srivasam@codeaurora.org>,
        agross@kernel.org, bjorn.andersson@linaro.org, lgirdwood@gmail.com,
        broonie@kernel.org, robh+dt@kernel.org, plai@codeaurora.org,
        bgoswami@codeaurora.org, perex@perex.cz, tiwai@suse.com,
        rohitkr@codeaurora.org, linux-arm-msm@vger.kernel.org,
        alsa-devel@alsa-project.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, swboyd@chromium.org,
        judyhsiao@chromium.org
Cc:     Venkata Prasad Potturu <potturu@codeaurora.org>
References: <1637239714-11211-1-git-send-email-srivasam@codeaurora.org>
 <1637239714-11211-5-git-send-email-srivasam@codeaurora.org>
From:   Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Message-ID: <03051fc7-5f52-2a09-4136-6a1c717c3e75@linaro.org>
Date:   Tue, 23 Nov 2021 12:27:59 +0000
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On 18/11/2021 12:48, Srinivasa Rao Mandadapu wrote:
> Add lpass cpu driver to support audio over codec dma for
> ADSP bypass usecase.
> 
> Signed-off-by: Srinivasa Rao Mandadapu <srivasam@codeaurora.org>
> Co-developed-by: Venkata Prasad Potturu <potturu@codeaurora.org>
> Signed-off-by: Venkata Prasad Potturu <potturu@codeaurora.org>
> ---
>   sound/soc/qcom/lpass-cdc-dma.c | 195 +++++++++++++++++++++++++++++++++++++++++
>   sound/soc/qcom/lpass.h         |   1 +
>   2 files changed, 196 insertions(+)
>   create mode 100644 sound/soc/qcom/lpass-cdc-dma.c
> 
> diff --git a/sound/soc/qcom/lpass-cdc-dma.c b/sound/soc/qcom/lpass-cdc-dma.c
> new file mode 100644
> index 0000000..f5bfda9
> --- /dev/null
> +++ b/sound/soc/qcom/lpass-cdc-dma.c
> @@ -0,0 +1,195 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2021 The Linux Foundation. All rights reserved.
> + *
> + * lpass-cdc-dma.c -- ALSA SoC WCD -CPU DAI driver for QTi LPASS WCD
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/module.h>
> +#include <sound/soc.h>
> +#include <sound/soc-dai.h>
> +
> +#include "lpass-lpaif-reg.h"
> +#include "lpass.h"
> +
> +static void __get_dmactl_handle(struct snd_pcm_substream *substream, struct snd_soc_dai *dai,
> +					struct lpaif_dmactl **dmactl, int *id)

Please rename this with an lpass prefix, Also indentation looks bit off 
here.

> +{
> +	struct snd_soc_pcm_runtime *soc_runtime = asoc_substream_to_rtd(substream);
> +	struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(soc_runtime, 0);
> +	struct lpass_data *drvdata = snd_soc_dai_get_drvdata(dai);
> +	struct snd_pcm_runtime *rt = substream->runtime;
> +	struct lpass_pcm_data *pcm_data = rt->private_data;
> +	struct lpass_variant *v = drvdata->variant;
> +	int dir = substream->stream;
> +	unsigned int dai_id = cpu_dai->driver->id;
> +
> +	if (dir == SNDRV_PCM_STREAM_PLAYBACK) {
> +		*dmactl = drvdata->rxtx_rd_dmactl;
> +		*id = pcm_data->dma_ch;
> +	} else {
> +		if (dai_id == LPASS_CDC_DMA_TX3) {
> +			*dmactl = drvdata->rxtx_wr_dmactl;
> +			*id = pcm_data->dma_ch - v->rxtx_wrdma_channel_start;
> +		} else if (dai_id == LPASS_CDC_DMA_VA_TX0) {
> +			*dmactl = drvdata->va_wr_dmactl;
> +			*id = pcm_data->dma_ch - v->va_wrdma_channel_start;
> +		}

use switch case here, also something like this makes more sense rather 
that just dealing with TX3 and VA TX0

switch (dai_id) {
case: LPASS_CDC_DMA_RX0 ... LPASS_CDC_DMA_RX8:
	*dmactl = drvdata->rxtx_wr_dmactl;
	*id = pcm_data->dma_ch;
	break;
case: LPASS_CDC_DMA_TX0 ... LPASS_CDC_DMA_TX8:
	*dmactl = drvdata->rxtx_wr_dmactl;
	*id = pcm_data->dma_ch - v->rxtx_wrdma_channel_start;
	break;
case LPASS_CDC_DMA_VA_TX0 ...  LPASS_CDC_DMA_VA_TX8:
	*dmactl = drvdata->rxtx_wr_dmactl;
	*id = pcm_data->dma_ch - v->va_wrdma_channel_start;
	break;
default:
	dev_err(dev, "Invalid dai id for dma ctl\n");
	break;
}

> +	}
> +}
> +
> +static int __lpass_platform_codec_intf_init(struct snd_soc_dai *dai,
> +					 struct snd_pcm_substream *substream)

Indentation is off, I think most of the code has simillar issue.

> +{
> +	struct snd_soc_pcm_runtime *soc_runtime = asoc_substream_to_rtd(substream);
> +	struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(soc_runtime, 0);
> +	struct lpaif_dmactl *dmactl;
> +	int dir = substream->stream;
> +	int ret, id, codec_intf;
> +	unsigned int dai_id = cpu_dai->driver->id;
> +
> +	if (dir == SNDRV_PCM_STREAM_PLAYBACK)
> +		codec_intf = LPASS_CDC_DMA_RX0_INTERFACE;

Why are we limiting this to just RX0, it should be trivial to add 
support to other RX and TX dais.

Add a helper to convert the dai ids to interface indexs

> +	else
> +		codec_intf = LPASS_CDC_DMA_INTERFACE(dai_id);
> +
> +	__get_dmactl_handle(substream, dai, &dmactl, &id);

We are not checking if dmactl is valid or not, best is to have a error 
returned from __get_dmactl_handle() and handle it properly here.
> +
> +	ret = regmap_fields_write(dmactl->codec_intf, id, codec_intf);
> +	if (ret) {
> +		dev_err(soc_runtime->dev,
Why not use a local declare a local dev pointer and use it here, it will 
save lines here.
> +			"error writing to dmactl codec_intf reg field: %d\n", ret);
> +		return ret;
> +	}
> +	ret = regmap_fields_write(dmactl->codec_fs_sel, id, 0x0);
> +	if (ret) {
> +		dev_err(soc_runtime->dev,
> +			"error writing to dmactl codec_fs_sel reg field: %d\n", ret);
> +		return ret;
> +	}
> +	ret = regmap_fields_write(dmactl->codec_fs_delay, id, 0x0);
> +	if (ret) {
> +		dev_err(soc_runtime->dev,
> +			"error writing to dmactl codec_fs_delay reg field: %d\n", ret);
> +		return ret;
> +	}
> +	ret = regmap_fields_write(dmactl->codec_pack, id, 0x1);
> +	if (ret) {
> +		dev_err(soc_runtime->dev,
> +			"error writing to dmactl codec_pack reg field: %d\n", ret);
> +		return ret;
> +	}
> +	ret = regmap_fields_write(dmactl->codec_enable, id, LPAIF_DMACTL_ENABLE_ON);
> +	if (ret) {
> +		dev_err(soc_runtime->dev,
> +			"error writing to dmactl codec_enable reg field: %d\n", ret);
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +static int lpass_wcd_daiops_startup(struct snd_pcm_substream *substream,
> +		struct snd_soc_dai *dai)
> +{
> +	struct lpass_data *drvdata = snd_soc_dai_get_drvdata(dai);
> +	int ret;
> +
> +	ret = clk_bulk_prepare_enable(drvdata->cdc_num_clks, drvdata->cdc_clks);
> +	if (ret) {
> +		dev_err(dai->dev, "error in enabling cdc dma clks: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;

may be just do
return clk_bulk_prepare_enable(drvdata->cdc_num_clks, drvdata->cdc_clks);

soc_dai_ret() should print an error if startup fails.


> +}
> +
> +static void lpass_wcd_daiops_shutdown(struct snd_pcm_substream *substream,
> +		struct snd_soc_dai *dai)
> +{
> +	struct lpass_data *drvdata = snd_soc_dai_get_drvdata(dai);
> +
> +	clk_bulk_disable_unprepare(drvdata->cdc_num_clks, drvdata->cdc_clks);
> +}
> +
> +static int lpass_wcd_daiops_hw_params(struct snd_pcm_substream *substream,
> +		struct snd_pcm_hw_params *params, struct snd_soc_dai *dai)
> +{
> +	struct snd_soc_pcm_runtime *soc_runtime = asoc_substream_to_rtd(substream);
> +	struct lpaif_dmactl *dmactl;
> +	unsigned int ret, regval;
> +	unsigned int channels = params_channels(params);
> +	int id;
> +
> +	__get_dmactl_handle(substream, dai, &dmactl, &id);

may be move it after switch case and handle the errors.
> +
> +	switch (channels) {
> +	case 1:
> +		regval = LPASS_CDC_DMA_INTF_ONE_CHANNEL;
> +		break;
> +	case 2:
> +		regval = LPASS_CDC_DMA_INTF_TWO_CHANNEL;
> +		break;
> +	case 4:
> +		regval = LPASS_CDC_DMA_INTF_FOUR_CHANNEL;
> +		break;
> +	case 6:
> +		regval = LPASS_CDC_DMA_INTF_SIX_CHANNEL;
> +		break;
> +	case 8:
> +		regval = LPASS_CDC_DMA_INTF_EIGHT_CHANNEL;
> +		break;
> +	default:
> +		dev_err(soc_runtime->dev, "invalid PCM config\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = regmap_fields_write(dmactl->codec_channel, id, regval);
> +	if (ret) {
> +		dev_err(soc_runtime->dev,
> +			"error writing to dmactl codec_channel reg field: %d\n", ret);
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +static int lpass_wcd_daiops_trigger(struct snd_pcm_substream *substream,
> +		int cmd, struct snd_soc_dai *dai)
> +{
> +	struct snd_soc_pcm_runtime *soc_runtime = asoc_substream_to_rtd(substream);
> +	struct lpaif_dmactl *dmactl;
> +	int ret = 0, id;
> +
> +	__get_dmactl_handle(substream, dai, &dmactl, &id);

move it inside the case where this is really used.

> +
> +	switch (cmd) {
> +	case SNDRV_PCM_TRIGGER_START:
> +	case SNDRV_PCM_TRIGGER_RESUME:
> +	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> +		__lpass_platform_codec_intf_init(dai, substream);
> +		break;
> +	case SNDRV_PCM_TRIGGER_STOP:
> +	case SNDRV_PCM_TRIGGER_SUSPEND:
> +	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> +		ret = regmap_fields_write(dmactl->codec_enable, id, LPAIF_DMACTL_ENABLE_OFF);
> +		if (ret) {
> +			dev_err(soc_runtime->dev,
> +				"error writing to dmactl codec_enable reg: %d\n", ret);
> +			return ret;
> +		}
> +
> +		break;

missing default:

> +	}
> +	return ret;
> +}
> +
> +const struct snd_soc_dai_ops asoc_qcom_lpass_wcd_dai_ops = {
> +	.startup	= lpass_wcd_daiops_startup,
> +	.shutdown	= lpass_wcd_daiops_shutdown,
> +	.hw_params	= lpass_wcd_daiops_hw_params,
> +	.trigger	= lpass_wcd_daiops_trigger,
> +};
> +EXPORT_SYMBOL_GPL(asoc_qcom_lpass_wcd_dai_ops);
> +
> +MODULE_DESCRIPTION("QTi LPASS CDC DMA Driver");
> +MODULE_LICENSE("GPL v2");

use
MODULE_LICENSE("GPL");

more info in ./Documentation/process/license-rules.rst

--srini
> diff --git a/sound/soc/qcom/lpass.h b/sound/soc/qcom/lpass.h
> index b068534..f912425 100644
> --- a/sound/soc/qcom/lpass.h
> +++ b/sound/soc/qcom/lpass.h
> @@ -414,5 +414,6 @@ int asoc_qcom_lpass_cpu_dai_probe(struct snd_soc_dai *dai);
>   extern const struct snd_soc_dai_ops asoc_qcom_lpass_cpu_dai_ops;
>   int lpass_cpu_pcm_new(struct snd_soc_pcm_runtime *rtd,
>   				struct snd_soc_dai *dai);
> +extern const struct snd_soc_dai_ops asoc_qcom_lpass_wcd_dai_ops;
>   
>   #endif /* __LPASS_H__ */
>