Re: [PATCH v2 1/6] ASoC: amd: acp: Add generic support for PDM controller on ACP

[Pierre-Louis Bossart]

couple of nit-picks:


> diff --git a/sound/soc/amd/acp/acp-pdm.c b/sound/soc/amd/acp/acp-pdm.c
> new file mode 100644
> index 000000000000..cb9bbd795eee
> --- /dev/null
> +++ b/sound/soc/amd/acp/acp-pdm.c
> @@ -0,0 +1,181 @@
> +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
> +//
> +// This file is provided under a dual BSD/GPLv2 license. When using or
> +// redistributing this file, you may do so under either license.
> +//
> +// Copyright(c) 2021 Advanced Micro Devices, Inc.

2022?

> +//
> +// Authors: Ajit Kumar Pandey <AjitKumar.Pandey@xxxxxxx>
> +//	    Vijendar Mukunda <Vijendar.Mukunda@xxxxxxx>
> +//
> +
> +/*
> + * Generic Hardware interface for ACP Audio PDM controller
> + */
> +
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <sound/pcm_params.h>
> +#include <sound/soc.h>
> +#include <sound/soc-dai.h>
> +#include <linux/dma-mapping.h>

alphabetical order?

> +
> +#include "amd.h"
> +
> +#define DRV_NAME "acp-pdm"
> +
> +#define PDM_DMA_STAT		0x10
> +#define PDM_DMA_INTR_MASK	0x10000
> +#define PDM_DEC_64		0x2
> +#define PDM_CLK_FREQ_MASK	0x07
> +#define PDM_MISC_CTRL_MASK	0x10
> +#define PDM_ENABLE		0x01
> +#define PDM_DISABLE		0x00
> +#define DMA_EN_MASK		0x02
> +#define DELAY_US		5
> +#define PDM_TIMEOUT		1000
> +
> +static int acp_dmic_dai_trigger(struct snd_pcm_substream *substream,
> +			       int cmd, struct snd_soc_dai *dai)
> +{
> +	struct acp_stream *stream = substream->runtime->private_data;
> +	struct device *dev = dai->component->dev;
> +	struct acp_dev_data *adata = dev_get_drvdata(dev);
> +	u32 physical_addr, size_dmic, period_bytes;
> +	unsigned int dma_enable;
> +	int ret = 0;
> +
> +	period_bytes = frames_to_bytes(substream->runtime,
> +			substream->runtime->period_size);
> +	size_dmic = frames_to_bytes(substream->runtime,
> +			substream->runtime->buffer_size);
> +
> +	physical_addr = stream->reg_offset + MEM_WINDOW_START;
> +
> +	/* Init DMIC Ring buffer */
> +	writel(physical_addr, adata->acp_base + ACP_WOV_RX_RINGBUFADDR);
> +	writel(size_dmic, adata->acp_base + ACP_WOV_RX_RINGBUFSIZE);
> +	writel(period_bytes, adata->acp_base + ACP_WOV_RX_INTR_WATERMARK_SIZE);
> +	writel(0x01, adata->acp_base + ACPAXI2AXI_ATU_CTRL);

could this be done in a .prepare step?

> +
> +	switch (cmd) {
> +	case SNDRV_PCM_TRIGGER_START:
> +	case SNDRV_PCM_TRIGGER_RESUME:
> +	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> +		dma_enable = readl(adata->acp_base + ACP_WOV_PDM_DMA_ENABLE);
> +		if (!(dma_enable & DMA_EN_MASK)) {
> +			writel(PDM_ENABLE, adata->acp_base + ACP_WOV_PDM_ENABLE);
> +			writel(PDM_ENABLE, adata->acp_base + ACP_WOV_PDM_DMA_ENABLE);
> +		}
> +
> +		ret = readl_poll_timeout_atomic(adata->acp_base + ACP_WOV_PDM_DMA_ENABLE,
> +						dma_enable, (dma_enable & DMA_EN_MASK),
> +						DELAY_US, PDM_TIMEOUT);
> +		break;
> +	case SNDRV_PCM_TRIGGER_STOP:
> +	case SNDRV_PCM_TRIGGER_SUSPEND:
> +	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> +		dma_enable = readl(adata->acp_base + ACP_WOV_PDM_DMA_ENABLE);
> +		if ((dma_enable & DMA_EN_MASK)) {
> +			writel(PDM_DISABLE, adata->acp_base + ACP_WOV_PDM_ENABLE);
> +			writel(PDM_DISABLE, adata->acp_base + ACP_WOV_PDM_DMA_ENABLE);
> +
> +		}
> +
> +		ret = readl_poll_timeout_atomic(adata->acp_base + ACP_WOV_PDM_DMA_ENABLE,
> +						dma_enable, !(dma_enable & DMA_EN_MASK),
> +						DELAY_US, PDM_TIMEOUT);

is the _atomic needed?

> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static int acp_dmic_hwparams(struct snd_pcm_substream *substream,
> +	struct snd_pcm_hw_params *hwparams, struct snd_soc_dai *dai)
> +{
> +	struct device *dev = dai->component->dev;
> +	struct acp_dev_data *adata = dev_get_drvdata(dev);
> +	unsigned int dmic_ctrl, channels, ch_mask;
> +
> +	/* Enable default DMIC clk */
> +	writel(PDM_CLK_FREQ_MASK, adata->acp_base + ACP_WOV_CLK_CTRL);
> +	dmic_ctrl = readl(adata->acp_base + ACP_WOV_MISC_CTRL);
> +	dmic_ctrl |= PDM_MISC_CTRL_MASK;
> +	writel(dmic_ctrl, adata->acp_base + ACP_WOV_MISC_CTRL);

.hw_params can be called multiple times, should this clock handling be
done in a .prepare step?

Or alternatively in .startup - this doesn't seem to depend on hardware
parameters?

> +
> +	channels = params_channels(hwparams);
> +	switch (channels) {
> +	case 2:
> +		ch_mask = 0;
> +		break;
> +	case 4:
> +		ch_mask = 1;
> +		break;
> +	case 6:
> +		ch_mask = 2;
> +		break;
> +	default:
> +		dev_err(dev, "Invalid channels %d\n", channels);
> +		return -EINVAL;
> +	}
> +
> +	if (params_format(hwparams) != SNDRV_PCM_FORMAT_S32_LE) {
> +		dev_err(dai->dev, "Invalid format:%d\n", params_format(hwparams));
> +		return -EINVAL;
> +	}
> +
> +	writel(ch_mask, adata->acp_base + ACP_WOV_PDM_NO_OF_CHANNELS);
> +	writel(PDM_DEC_64, adata->acp_base + ACP_WOV_PDM_DECIMATION_FACTOR);
> +
> +	return 0;
> +}

> +MODULE_LICENSE("GPL v2");

"GPL" is enough