Soundwire 的 Machine Driver

sof_sdw.c 這個文件實現了Intel 新Soundwire 平臺的Machine Driver
sof_sdw - ASOC Machine driver for Intel SoundWire platforms

sof_sdw_rt5682.c

static struct sof_sdw_codec_info codec_info_list[] = {
	{
		.id = 0x700,
		.direction = {true, true},
		.dai_name = "rt700-aif1",
		.init = sof_sdw_rt700_init,
	},
	{
		.id = 0x711,
		.direction = {true, true},
		.dai_name = "rt711-aif1",
		.init = sof_sdw_rt711_init,
	},
	{
		.id = 0x1308,
		.acpi_id = "10EC1308",
		.direction = {true, false},
		.dai_name = "rt1308-aif",
		.ops = &sof_sdw_rt1308_i2s_ops,
		.init = sof_sdw_rt1308_init,
	},
	{
		.id = 0x715,
		.direction = {false, true},
		.dai_name = "rt715-aif2",
		.init = sof_sdw_rt715_init,
	},
	{
		.id = 0x5682,
		.direction = {true, true},
		.dai_name = "rt5682-sdw",
		.init = sof_sdw_rt5682_init,
	},
};

/* SoC card */
struct snd_soc_card {
	
...
/* CPU <--> Codec DAI links  */
	struct snd_soc_dai_link *dai_link;  /* predefined links only */
	int num_links;  /* predefined links only */
...
}

Machine Driver 結構體define,
snd_soc_card 代表一個新的聲卡實例

/* sof audio machine driver for rt5682 codec */
static struct snd_soc_card sof_audio_card_rt5682 = {
	.name = "rt5682", /* the sof- prefix is added by the core */
	.owner = THIS_MODULE,
	.controls = sof_controls,
	.num_controls = ARRAY_SIZE(sof_controls),
	.dapm_widgets = sof_widgets,
	.num_dapm_widgets = ARRAY_SIZE(sof_widgets),
	.dapm_routes = sof_map,
	.num_dapm_routes = ARRAY_SIZE(sof_map),
	.fully_routed = true,
	.late_probe = sof_card_late_probe,
};

創建Platform 的Dai link 就是CPU_DAI ，然後通過上面的
struct snd_soc_dai_link *dai_link;
實現了Machine Driver 對Platform 和Codec 的連接功能

dai_links = sof_card_dai_links_create(&pdev->dev, ssp_codec, ssp_amp,
					      dmic_be_num, hdmi_num);
	if (!dai_links)
		return -ENOMEM;

	sof_audio_card_rt5682.dai_link = dai_links;

這裏貼一下上面的sof_card_dai_links_create的實現,可以看到這個函數中創建了很多的SSP,DMIC,HDMI 的link
就是這個link ：
struct snd_soc_dai_link *links;
這裏的links[id] 數組包括了所有platform 的Dai Link ,這個函數是實現的關鍵.
這個links是這樣生成的:

links = devm_kzalloc(dev, sizeof(struct snd_soc_dai_link) *
sof_audio_card_rt5682.num_links, GFP_KERNEL);

的數值是這樣賦值的：基本都在probe 函數中做了 初始化.

if (soc_intel_is_byt() || soc_intel_is_cht()) {
	is_legacy_cpu = 1;
	dmic_be_num = 0;
	hdmi_num = 0;
	/* default quirk for legacy cpu */
	sof_rt5682_quirk = SOF_RT5682_MCLK_EN |
					SOF_RT5682_MCLK_BYTCHT_EN |
					SOF_RT5682_SSP_CODEC(2);
} else {
	dmic_be_num = 2;
	hdmi_num = (sof_rt5682_quirk & SOF_RT5682_NUM_HDMIDEV_MASK) >>
		 SOF_RT5682_NUM_HDMIDEV_SHIFT;
	/* default number of HDMI DAI's */
	if (!hdmi_num)
		hdmi_num = 3;
}

sof_audio_probe(){
…
/* compute number of dai links /
sof_audio_card_rt5682.num_links = 1 + dmic_be_num + hdmi_num;
…
}
/ codec SSP */
links[id].name = devm_kasprintf(dev, GFP_KERNEL,
“SSP%d-Codec”, ssp_codec);

sof_card_dai_links_create

static struct snd_soc_dai_link *sof_card_dai_links_create(struct device *dev,
							  int ssp_codec,
							  int ssp_amp,
							  int dmic_be_num,
							  int hdmi_num)
{
	struct snd_soc_dai_link_component *idisp_components;
	struct snd_soc_dai_link_component *cpus;
	struct snd_soc_dai_link *links;
	int i, id = 0;

	links = devm_kzalloc(dev, sizeof(struct snd_soc_dai_link) *
			     sof_audio_card_rt5682.num_links, GFP_KERNEL);
	cpus = devm_kzalloc(dev, sizeof(struct snd_soc_dai_link_component) *
			     sof_audio_card_rt5682.num_links, GFP_KERNEL);
	if (!links || !cpus)
		goto devm_err;

	/* codec SSP */
	links[id].name = devm_kasprintf(dev, GFP_KERNEL,
					"SSP%d-Codec", ssp_codec);
	if (!links[id].name)
		goto devm_err;

	links[id].id = id;
	links[id].codecs = rt5682_component;
	links[id].num_codecs = ARRAY_SIZE(rt5682_component);
	links[id].platforms = platform_component;
	links[id].num_platforms = ARRAY_SIZE(platform_component);
	links[id].init = sof_rt5682_codec_init;
	links[id].ops = &sof_rt5682_ops;
	links[id].nonatomic = true;
	links[id].dpcm_playback = 1;
	links[id].dpcm_capture = 1;
	links[id].no_pcm = 1;
	links[id].cpus = &cpus[id];
	links[id].num_cpus = 1;
	if (is_legacy_cpu) {
		links[id].cpus->dai_name = devm_kasprintf(dev, GFP_KERNEL,
							  "ssp%d-port",
							  ssp_codec);
		if (!links[id].cpus->dai_name)
			goto devm_err;
	} else {
		/*
		 * Currently, On SKL+ platforms MCLK will be turned off in sof
		 * runtime suspended, and it will go into runtime suspended
		 * right after playback is stop. However, rt5682 will output
		 * static noise if sysclk turns off during playback. Set
		 * ignore_pmdown_time to power down rt5682 immediately and
		 * avoid the noise.
		 * It can be removed once we can control MCLK by driver.
		 */
		links[id].ignore_pmdown_time = 1;
		links[id].cpus->dai_name = devm_kasprintf(dev, GFP_KERNEL,
							  "SSP%d Pin",
							  ssp_codec);
		if (!links[id].cpus->dai_name)
			goto devm_err;
	}
	id++;

	/* dmic */
	if (dmic_be_num > 0) {
		/* at least we have dmic01 */
		links[id].name = "dmic01";
		links[id].cpus = &cpus[id];
		links[id].cpus->dai_name = "DMIC01 Pin";
		links[id].init = dmic_init;
		if (dmic_be_num > 1) {
			/* set up 2 BE links at most */
			links[id + 1].name = "dmic16k";
			links[id + 1].cpus = &cpus[id + 1];
			links[id + 1].cpus->dai_name = "DMIC16k Pin";
			dmic_be_num = 2;
		}
	}

	for (i = 0; i < dmic_be_num; i++) {
		links[id].id = id;
		links[id].num_cpus = 1;
		links[id].codecs = dmic_component;
		links[id].num_codecs = ARRAY_SIZE(dmic_component);
		links[id].platforms = platform_component;
		links[id].num_platforms = ARRAY_SIZE(platform_component);
		links[id].ignore_suspend = 1;
		links[id].dpcm_capture = 1;
		links[id].no_pcm = 1;
		id++;
	}

	/* HDMI */
	if (hdmi_num > 0) {
		idisp_components = devm_kzalloc(dev,
				   sizeof(struct snd_soc_dai_link_component) *
				   hdmi_num, GFP_KERNEL);
		if (!idisp_components)
			goto devm_err;
	}
	for (i = 1; i <= hdmi_num; i++) {
		links[id].name = devm_kasprintf(dev, GFP_KERNEL,
						"iDisp%d", i);
		if (!links[id].name)
			goto devm_err;

		links[id].id = id;
		links[id].cpus = &cpus[id];
		links[id].num_cpus = 1;
		links[id].cpus->dai_name = devm_kasprintf(dev, GFP_KERNEL,
							  "iDisp%d Pin", i);
		if (!links[id].cpus->dai_name)
			goto devm_err;

		idisp_components[i - 1].name = "ehdaudio0D2";
		idisp_components[i - 1].dai_name = devm_kasprintf(dev,
								  GFP_KERNEL,
								  "intel-hdmi-hifi%d",
								  i);
		if (!idisp_components[i - 1].dai_name)
			goto devm_err;

		links[id].codecs = &idisp_components[i - 1];
		links[id].num_codecs = 1;
		links[id].platforms = platform_component;
		links[id].num_platforms = ARRAY_SIZE(platform_component);
		links[id].init = sof_hdmi_init;
		links[id].dpcm_playback = 1;
		links[id].no_pcm = 1;
		id++;
	}

	/* speaker amp */
	if (sof_rt5682_quirk & SOF_SPEAKER_AMP_PRESENT) {
		links[id].name = devm_kasprintf(dev, GFP_KERNEL,
						"SSP%d-Codec", ssp_amp);
		if (!links[id].name)
			goto devm_err;

		links[id].id = id;
		if (sof_rt5682_quirk & SOF_RT1015_SPEAKER_AMP_PRESENT) {
			links[id].codecs = rt1015_components;
			links[id].num_codecs = ARRAY_SIZE(rt1015_components);
			links[id].init = speaker_codec_init_lr;
			links[id].ops = &sof_rt1015_ops;
		} else if (sof_rt5682_quirk &
				SOF_MAX98373_SPEAKER_AMP_PRESENT) {
			links[id].codecs = max_98373_components;
			links[id].num_codecs = ARRAY_SIZE(max_98373_components);
			links[id].init = max98373_spk_codec_init;
			links[id].ops = &max_98373_ops;
		} else {
			links[id].codecs = max98357a_component;
			links[id].num_codecs = ARRAY_SIZE(max98357a_component);
			links[id].init = speaker_codec_init;
		}
		links[id].platforms = platform_component;
		links[id].num_platforms = ARRAY_SIZE(platform_component);
		links[id].nonatomic = true;
		links[id].dpcm_playback = 1;
		links[id].no_pcm = 1;
		links[id].cpus = &cpus[id];
		links[id].num_cpus = 1;
		if (is_legacy_cpu) {
			links[id].cpus->dai_name = devm_kasprintf(dev, GFP_KERNEL,
								  "ssp%d-port",
								  ssp_amp);
			if (!links[id].cpus->dai_name)
				goto devm_err;

		} else {
			links[id].cpus->dai_name = devm_kasprintf(dev, GFP_KERNEL,
								  "SSP%d Pin",
								  ssp_amp);
			if (!links[id].cpus->dai_name)
				goto devm_err;
		}
	}

	return links;
devm_err:
	return NULL;
}

sof_audio_probe

static int sof_audio_probe(struct platform_device *pdev)
{
	struct snd_soc_dai_link *dai_links;
	struct snd_soc_acpi_mach *mach;
	struct sof_card_private *ctx;
	int dmic_be_num, hdmi_num;
	int ret, ssp_amp, ssp_codec;

	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
	if (!ctx)
		return -ENOMEM;

	if (pdev->id_entry && pdev->id_entry->driver_data)
		sof_rt5682_quirk = (unsigned long)pdev->id_entry->driver_data;

	dmi_check_system(sof_rt5682_quirk_table);

	mach = pdev->dev.platform_data;

	/* A speaker amp might not be present when the quirk claims one is.
	 * Detect this via whether the machine driver match includes quirk_data.
	 */
	if ((sof_rt5682_quirk & SOF_SPEAKER_AMP_PRESENT) && !mach->quirk_data)
		sof_rt5682_quirk &= ~SOF_SPEAKER_AMP_PRESENT;

	if (soc_intel_is_byt() || soc_intel_is_cht()) {
		is_legacy_cpu = 1;
		dmic_be_num = 0;
		hdmi_num = 0;
		/* default quirk for legacy cpu */
		sof_rt5682_quirk = SOF_RT5682_MCLK_EN |
						SOF_RT5682_MCLK_BYTCHT_EN |
						SOF_RT5682_SSP_CODEC(2);
	} else {
		dmic_be_num = 2;
		hdmi_num = (sof_rt5682_quirk & SOF_RT5682_NUM_HDMIDEV_MASK) >>
			 SOF_RT5682_NUM_HDMIDEV_SHIFT;
		/* default number of HDMI DAI's */
		if (!hdmi_num)
			hdmi_num = 3;
	}

	/* need to get main clock from pmc */
	if (sof_rt5682_quirk & SOF_RT5682_MCLK_BYTCHT_EN) {
		ctx->mclk = devm_clk_get(&pdev->dev, "pmc_plt_clk_3");
		if (IS_ERR(ctx->mclk)) {
			ret = PTR_ERR(ctx->mclk);

			dev_err(&pdev->dev,
				"Failed to get MCLK from pmc_plt_clk_3: %d\n",
				ret);
			return ret;
		}

		ret = clk_prepare_enable(ctx->mclk);
		if (ret < 0) {
			dev_err(&pdev->dev,
				"could not configure MCLK state");
			return ret;
		}
	}

	dev_dbg(&pdev->dev, "sof_rt5682_quirk = %lx\n", sof_rt5682_quirk);

	ssp_amp = (sof_rt5682_quirk & SOF_RT5682_SSP_AMP_MASK) >>
			SOF_RT5682_SSP_AMP_SHIFT;

	ssp_codec = sof_rt5682_quirk & SOF_RT5682_SSP_CODEC_MASK;

	/* compute number of dai links */
	sof_audio_card_rt5682.num_links = 1 + dmic_be_num + hdmi_num;

	if (sof_rt5682_quirk & SOF_SPEAKER_AMP_PRESENT)
		sof_audio_card_rt5682.num_links++;

	if (sof_rt5682_quirk & SOF_MAX98373_SPEAKER_AMP_PRESENT)
		sof_max98373_codec_conf(&sof_audio_card_rt5682);

	dai_links = sof_card_dai_links_create(&pdev->dev, ssp_codec, ssp_amp,
					      dmic_be_num, hdmi_num);
	if (!dai_links)
		return -ENOMEM;

	sof_audio_card_rt5682.dai_link = dai_links;

	if (sof_rt5682_quirk & SOF_RT1015_SPEAKER_AMP_PRESENT) {
		sof_audio_card_rt5682.codec_conf = rt1015_amp_conf;
		sof_audio_card_rt5682.num_configs = ARRAY_SIZE(rt1015_amp_conf);
	}

	INIT_LIST_HEAD(&ctx->hdmi_pcm_list);

	sof_audio_card_rt5682.dev = &pdev->dev;

	/* set platform name for each dailink */
	ret = snd_soc_fixup_dai_links_platform_name(&sof_audio_card_rt5682,
						    mach->mach_params.platform);
	if (ret)
		return ret;

	ctx->common_hdmi_codec_drv = mach->mach_params.common_hdmi_codec_drv;

	snd_soc_card_set_drvdata(&sof_audio_card_rt5682, ctx);

	return devm_snd_soc_register_card(&pdev->dev,
					  &sof_audio_card_rt5682);
}