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Message-ID: <7af39ea4-f120-43a2-b023-fa281ff05966@linux.intel.com>
Date:   Tue, 17 Oct 2023 16:46:24 -0500
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Subject: Re: [PATCH v9 11/34] ASoC: qcom: qdsp6: Add USB backend ASoC driver
 for Q6
Content-Language: en-US
To:     Wesley Cheng <quic_wcheng@quicinc.com>, mathias.nyman@intel.com,
        gregkh@linuxfoundation.org, lgirdwood@gmail.com,
        broonie@kernel.org, perex@perex.cz, tiwai@suse.com,
        agross@kernel.org, andersson@kernel.org, konrad.dybcio@linaro.org,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        conor+dt@kernel.org, srinivas.kandagatla@linaro.org,
        bgoswami@quicinc.com, Thinh.Nguyen@synopsys.com
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        alsa-devel@alsa-project.org, linux-arm-msm@vger.kernel.org,
        devicetree@vger.kernel.org
References: <20231017200109.11407-1-quic_wcheng@quicinc.com>
 <20231017200109.11407-12-quic_wcheng@quicinc.com>
From:   Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
In-Reply-To: <20231017200109.11407-12-quic_wcheng@quicinc.com>
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> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/device.h>

alphabetical order?

> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/iommu.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dma-map-ops.h>
> +
> +#include <sound/pcm.h>
> +#include <sound/soc.h>
> +#include <sound/soc-usb.h>
> +#include <sound/pcm_params.h>
> +#include <sound/asound.h>
> +#include <sound/q6usboffload.h>
> +
> +#include "q6dsp-lpass-ports.h"
> +#include "q6afe.h"
> +
> +#define SID_MASK	0xF

Prefix? e.g. Q6_USB_SID_MASK?

> +
> +struct q6usb_port_data {
> +	struct q6afe_usb_cfg usb_cfg;
> +	struct snd_soc_usb *usb;
> +	struct q6usb_offload priv;
> +	int active_idx;

index of what?

> +};
> +
> +static const struct snd_soc_dapm_widget q6usb_dai_widgets[] = {
> +	SND_SOC_DAPM_HP("USB_RX_BE", NULL),
> +};
> +
> +static const struct snd_soc_dapm_route q6usb_dapm_routes[] = {
> +	{"USB Playback", NULL, "USB_RX_BE"},
> +};
> +
> +static int q6usb_hw_params(struct snd_pcm_substream *substream,
> +			   struct snd_pcm_hw_params *params,
> +			   struct snd_soc_dai *dai)
> +{
> +	return 0;
> +}
> +
> +static const struct snd_soc_dai_ops q6usb_ops = {
> +	.hw_params = q6usb_hw_params,
> +};
> +
> +static struct snd_soc_dai_driver q6usb_be_dais[] = {
> +	{
> +		.playback = {
> +			.stream_name = "USB BE RX",
> +			.rates = SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_11025 |
> +				SNDRV_PCM_RATE_16000 | SNDRV_PCM_RATE_22050 |
> +				SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_44100 |
> +				SNDRV_PCM_RATE_48000 | SNDRV_PCM_RATE_96000 |
> +				SNDRV_PCM_RATE_192000,
> +			.formats = SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
> +				SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_U16_BE |
> +				SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
> +				SNDRV_PCM_FMTBIT_U24_LE | SNDRV_PCM_FMTBIT_U24_BE,
> +			.channels_min = 1,
> +			.channels_max = 2,
> +			.rate_max =     192000,
> +			.rate_min =	8000,
> +		},
> +		.id = USB_RX,
> +		.name = "USB_RX_BE",
> +		.ops = &q6usb_ops,
> +	},
> +};

This is a bit confusing.

In patch 9/34 you have a

static struct snd_soc_dai_driver q6dsp_audio_fe_dais[] = {

but this was not described anywhere in your cover letter.

or maybe this referred to the 'Q6AFE "cpu"', in which case you have
inconsistent naming between q6dsp and q6afe?

> +
> +static int q6usb_audio_ports_of_xlate_dai_name(struct snd_soc_component *component,
> +					const struct of_phandle_args *args,
> +					const char **dai_name)
> +{
> +	int id = args->args[0];
> +	int ret = -EINVAL;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(q6usb_be_dais); i++) {
> +		if (q6usb_be_dais[i].id == id) {
> +			*dai_name = q6usb_be_dais[i].name;
> +			ret = 0;
> +			break;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static int q6usb_alsa_connection_cb(struct snd_soc_usb *usb,
> +			struct snd_soc_usb_device *sdev, bool connected)
> +{
> +	struct q6usb_port_data *data;
> +
> +	if (!usb->component)
> +		return -ENODEV;
> +
> +	data = dev_get_drvdata(usb->component->dev);
> +
> +	if (connected) {
> +		/* We only track the latest USB headset plugged in */
> +		data->active_idx = sdev->card_idx;
> +	}
> +
> +	return 0;
> +}
> +
> +static int q6usb_component_probe(struct snd_soc_component *component)
> +{
> +	struct q6usb_port_data *data = dev_get_drvdata(component->dev);
> +
> +	data->usb = snd_soc_usb_add_port(component->dev, &data->priv, q6usb_alsa_connection_cb);

There is a conceptual problem here wrt. resource allocation.

snd_soc_usb_add_port() uses devm_kzalloc().

This cannot be used in a component probe, this has to be used in a real
driver probe.

> +	if (IS_ERR(data->usb)) {
> +		dev_err(component->dev, "failed to add usb port\n");
> +		return -ENODEV;
> +	}
> +
> +	data->usb->component = component;
> +
> +	return 0;
> +}
> +
> +static void q6usb_component_remove(struct snd_soc_component *component)
> +{
> +	snd_soc_usb_remove_port(component->dev);

and here as well, this should free the "struct snd_soc_usb *usb"
allocated in the probe. relying on devm_ is not quite right. Or if you
use devm_, you have to call it from the platform driver .probe.

> +static struct platform_driver q6usb_dai_platform_driver = {
> +	.driver = {
> +		.name = "q6usb-dai",
> +		.of_match_table = of_match_ptr(q6usb_dai_device_id),
> +	},
> +	.probe = q6usb_dai_dev_probe,
> +	/*
> +	 * Remove not required as resources are cleaned up as part of
> +	 * component removal.  Others are device managed resources.
> +	 */
> +};
> +module_platform_driver(q6usb_dai_platform_driver);
> +
> +MODULE_DESCRIPTION("Q6 USB backend dai driver");
> +MODULE_LICENSE("GPL");