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Message-ID: <4780ebf6-2596-107e-a150-5801c53824b6@linux.intel.com>
Date:   Tue, 1 Mar 2022 07:52:22 -0600
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Subject: Re: [PATCH v3 1/3] soundwire: qcom: add runtime pm support
Content-Language: en-US
To:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        robh+dt@kernel.org, vkoul@kernel.org,
        yung-chuan.liao@linux.intel.com
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        alsa-devel@alsa-project.org, quic_srivasam@quicinc.com
References: <20220228172528.3489-1-srinivas.kandagatla@linaro.org>
 <20220228172528.3489-2-srinivas.kandagatla@linaro.org>
From:   Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
In-Reply-To: <20220228172528.3489-2-srinivas.kandagatla@linaro.org>
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Precedence: bulk


On 2/28/22 11:25, Srinivas Kandagatla wrote:
> Add support to runtime PM using SoundWire clock stop Mode0 on supported
> controller instances and soft reset on instances that do not support
> clock stop.
> 
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

> ---
>  drivers/soundwire/qcom.c | 156 ++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 155 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
> index 54813417ef8e..810232686196 100644
> --- a/drivers/soundwire/qcom.c
> +++ b/drivers/soundwire/qcom.c
> @@ -11,6 +11,7 @@
>  #include <linux/of.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_device.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/regmap.h>
>  #include <linux/slab.h>
>  #include <linux/slimbus.h>
> @@ -20,6 +21,9 @@
>  #include <sound/soc.h>
>  #include "bus.h"
>  
> +#define SWRM_COMP_SW_RESET					0x008
> +#define SWRM_COMP_STATUS					0x014
> +#define SWRM_FRM_GEN_ENABLED					BIT(0)
>  #define SWRM_COMP_HW_VERSION					0x00
>  #define SWRM_COMP_CFG_ADDR					0x04
>  #define SWRM_COMP_CFG_IRQ_LEVEL_OR_PULSE_MSK			BIT(1)
> @@ -29,6 +33,7 @@
>  #define SWRM_COMP_PARAMS_RD_FIFO_DEPTH				GENMASK(19, 15)
>  #define SWRM_COMP_PARAMS_DOUT_PORTS_MASK			GENMASK(4, 0)
>  #define SWRM_COMP_PARAMS_DIN_PORTS_MASK				GENMASK(9, 5)
> +#define SWRM_COMP_MASTER_ID					0x104
>  #define SWRM_INTERRUPT_STATUS					0x200
>  #define SWRM_INTERRUPT_STATUS_RMSK				GENMASK(16, 0)
>  #define SWRM_INTERRUPT_STATUS_SLAVE_PEND_IRQ			BIT(0)
> @@ -111,6 +116,13 @@
>  #define SWR_MAX_CMD_ID	14
>  #define MAX_FIFO_RD_RETRY 3
>  #define SWR_OVERFLOW_RETRY_COUNT 30
> +#define SWRM_LINK_STATUS_RETRY_CNT 100
> +
> +enum {
> +	MASTER_ID_WSA = 1,
> +	MASTER_ID_RX,
> +	MASTER_ID_TX
> +};
>  
>  struct qcom_swrm_port_config {
>  	u8 si;
> @@ -159,6 +171,7 @@ struct qcom_swrm_ctrl {
>  	u32 slave_status;
>  	u32 wr_fifo_depth;
>  	u32 rd_fifo_depth;
> +	bool clock_stop_not_supported;
>  };
>  
>  struct qcom_swrm_data {
> @@ -497,6 +510,7 @@ static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id)
>  	u32 i;
>  	int devnum;
>  	int ret = IRQ_HANDLED;
> +	clk_prepare_enable(swrm->hclk);
>  
>  	swrm->reg_read(swrm, SWRM_INTERRUPT_STATUS, &intr_sts);
>  	intr_sts_masked = intr_sts & swrm->intr_mask;
> @@ -604,6 +618,7 @@ static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id)
>  		intr_sts_masked = intr_sts & swrm->intr_mask;
>  	} while (intr_sts_masked);
>  
> +	clk_disable_unprepare(swrm->hclk);
>  	return ret;
>  }
>  
> @@ -1017,6 +1032,15 @@ static int qcom_swrm_startup(struct snd_pcm_substream *substream,
>  	struct snd_soc_dai *codec_dai;
>  	int ret, i;
>  
> +	ret = pm_runtime_get_sync(ctrl->dev);
> +	if (ret < 0 && ret != -EACCES) {
> +		dev_err_ratelimited(ctrl->dev,
> +				    "pm_runtime_get_sync failed in %s, ret %d\n",
> +				    __func__, ret);
> +		pm_runtime_put_noidle(ctrl->dev);
> +		return ret;
> +	}
> +
>  	sruntime = sdw_alloc_stream(dai->name);
>  	if (!sruntime)
>  		return -ENOMEM;
> @@ -1044,6 +1068,9 @@ static void qcom_swrm_shutdown(struct snd_pcm_substream *substream,
>  
>  	sdw_release_stream(ctrl->sruntime[dai->id]);
>  	ctrl->sruntime[dai->id] = NULL;
> +	pm_runtime_mark_last_busy(ctrl->dev);
> +	pm_runtime_put_autosuspend(ctrl->dev);
> +
>  }
>  
>  static const struct snd_soc_dai_ops qcom_swrm_pdm_dai_ops = {
> @@ -1197,12 +1224,23 @@ static int qcom_swrm_get_port_config(struct qcom_swrm_ctrl *ctrl)
>  static int swrm_reg_show(struct seq_file *s_file, void *data)
>  {
>  	struct qcom_swrm_ctrl *swrm = s_file->private;
> -	int reg, reg_val;
> +	int reg, reg_val, ret;
> +
> +	ret = pm_runtime_get_sync(swrm->dev);
> +	if (ret < 0 && ret != -EACCES) {
> +		dev_err_ratelimited(swrm->dev,
> +				    "pm_runtime_get_sync failed in %s, ret %d\n",
> +				    __func__, ret);
> +		pm_runtime_put_noidle(swrm->dev);
> +	}
>  
>  	for (reg = 0; reg <= SWR_MSTR_MAX_REG_ADDR; reg += 4) {
>  		swrm->reg_read(swrm, reg, &reg_val);
>  		seq_printf(s_file, "0x%.3x: 0x%.2x\n", reg, reg_val);
>  	}
> +	pm_runtime_mark_last_busy(swrm->dev);
> +	pm_runtime_put_autosuspend(swrm->dev);
> +
>  
>  	return 0;
>  }
> @@ -1267,6 +1305,7 @@ static int qcom_swrm_probe(struct platform_device *pdev)
>  	ctrl->bus.ops = &qcom_swrm_ops;
>  	ctrl->bus.port_ops = &qcom_swrm_port_ops;
>  	ctrl->bus.compute_params = &qcom_swrm_compute_params;
> +	ctrl->bus.clk_stop_timeout = 300;
>  
>  	ret = qcom_swrm_get_port_config(ctrl);
>  	if (ret)
> @@ -1319,6 +1358,21 @@ static int qcom_swrm_probe(struct platform_device *pdev)
>  		 (ctrl->version >> 24) & 0xff, (ctrl->version >> 16) & 0xff,
>  		 ctrl->version & 0xffff);
>  
> +	pm_runtime_set_autosuspend_delay(dev, 3000);
> +	pm_runtime_use_autosuspend(dev);
> +	pm_runtime_mark_last_busy(dev);
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +
> +	/* Clk stop is not supported on WSA Soundwire masters */
> +	if (ctrl->version <= 0x01030000) {
> +		ctrl->clock_stop_not_supported = true;
> +	} else {
> +		ctrl->reg_read(ctrl, SWRM_COMP_MASTER_ID, &val);
> +		if (val == MASTER_ID_WSA)
> +			ctrl->clock_stop_not_supported = true;
> +	}
> +
>  #ifdef CONFIG_DEBUG_FS
>  	ctrl->debugfs = debugfs_create_dir("qualcomm-sdw", ctrl->bus.debugfs);
>  	debugfs_create_file("qualcomm-registers", 0400, ctrl->debugfs, ctrl,
> @@ -1345,6 +1399,105 @@ static int qcom_swrm_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static bool swrm_wait_for_frame_gen_enabled(struct qcom_swrm_ctrl *swrm)
> +{
> +	int retry = SWRM_LINK_STATUS_RETRY_CNT;
> +	int comp_sts;
> +
> +	do {
> +		swrm->reg_read(swrm, SWRM_COMP_STATUS, &comp_sts);
> +
> +		if (comp_sts & SWRM_FRM_GEN_ENABLED)
> +			return true;
> +
> +		usleep_range(500, 510);
> +	} while (retry--);
> +
> +	dev_err(swrm->dev, "%s: link status not %s\n", __func__,
> +		comp_sts && SWRM_FRM_GEN_ENABLED ? "connected" : "disconnected");
> +
> +	return false;
> +}
> +
> +static int swrm_runtime_resume(struct device *dev)
> +{
> +	struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dev);
> +	int ret;
> +
> +	clk_prepare_enable(ctrl->hclk);
> +
> +	if (ctrl->clock_stop_not_supported) {
> +		reinit_completion(&ctrl->enumeration);
> +		ctrl->reg_write(ctrl, SWRM_COMP_SW_RESET, 0x01);
> +		usleep_range(100, 105);
> +
> +		qcom_swrm_init(ctrl);
> +
> +		usleep_range(100, 105);
> +		if (!swrm_wait_for_frame_gen_enabled(ctrl))
> +			dev_err(ctrl->dev, "link failed to connect\n");
> +
> +		/* wait for hw enumeration to complete */
> +		wait_for_completion_timeout(&ctrl->enumeration,
> +					    msecs_to_jiffies(TIMEOUT_MS));
> +		qcom_swrm_get_device_status(ctrl);
> +		sdw_handle_slave_status(&ctrl->bus, ctrl->status);
> +	} else {
> +		ctrl->reg_write(ctrl, SWRM_MCP_BUS_CTRL, SWRM_MCP_BUS_CLK_START);
> +		ctrl->reg_write(ctrl, SWRM_INTERRUPT_CLEAR,
> +			SWRM_INTERRUPT_STATUS_MASTER_CLASH_DET);
> +
> +		ctrl->intr_mask |= SWRM_INTERRUPT_STATUS_MASTER_CLASH_DET;
> +		ctrl->reg_write(ctrl, SWRM_INTERRUPT_MASK_ADDR, ctrl->intr_mask);
> +		ctrl->reg_write(ctrl, SWRM_INTERRUPT_CPU_EN, ctrl->intr_mask);
> +
> +		usleep_range(100, 105);
> +		if (!swrm_wait_for_frame_gen_enabled(ctrl))
> +			dev_err(ctrl->dev, "link failed to connect\n");
> +
> +		ret = sdw_bus_exit_clk_stop(&ctrl->bus);
> +		if (ret < 0)
> +			dev_err(ctrl->dev, "bus failed to exit clock stop %d\n", ret);
> +	}
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused swrm_runtime_suspend(struct device *dev)
> +{
> +	struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dev);
> +	int ret;
> +
> +	if (!ctrl->clock_stop_not_supported) {
> +		/* Mask bus clash interrupt */
> +		ctrl->intr_mask &= ~SWRM_INTERRUPT_STATUS_MASTER_CLASH_DET;
> +		ctrl->reg_write(ctrl, SWRM_INTERRUPT_MASK_ADDR, ctrl->intr_mask);
> +		ctrl->reg_write(ctrl, SWRM_INTERRUPT_CPU_EN, ctrl->intr_mask);
> +		/* Prepare slaves for clock stop */
> +		ret = sdw_bus_prep_clk_stop(&ctrl->bus);
> +		if (ret < 0 && ret != -ENODATA) {
> +			dev_err(dev, "prepare clock stop failed %d", ret);
> +			return ret;
> +		}
> +
> +		ret = sdw_bus_clk_stop(&ctrl->bus);
> +		if (ret < 0 && ret != -ENODATA) {
> +			dev_err(dev, "bus clock stop failed %d", ret);
> +			return ret;
> +		}
> +	}
> +
> +	clk_disable_unprepare(ctrl->hclk);
> +
> +	usleep_range(300, 305);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops swrm_dev_pm_ops = {
> +	SET_RUNTIME_PM_OPS(swrm_runtime_suspend, swrm_runtime_resume, NULL)
> +};
> +
>  static const struct of_device_id qcom_swrm_of_match[] = {
>  	{ .compatible = "qcom,soundwire-v1.3.0", .data = &swrm_v1_3_data },
>  	{ .compatible = "qcom,soundwire-v1.5.1", .data = &swrm_v1_5_data },
> @@ -1359,6 +1512,7 @@ static struct platform_driver qcom_swrm_driver = {
>  	.driver = {
>  		.name	= "qcom-soundwire",
>  		.of_match_table = qcom_swrm_of_match,
> +		.pm = &swrm_dev_pm_ops,
>  	}
>  };
>  module_platform_driver(qcom_swrm_driver);