Re: [PATCH 1/3] soundwire: qcom: add runtime pm support

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 22/02/2022 19:15, Pierre-Louis Bossart wrote:


On 2/21/22 04:41, Srinivas Kandagatla wrote:
Add support to runtime PM using SoundWire clock stop on supported instances
and bus reset on instances that require full reset.

This commit message and code are a bit confusing, e.g. you have a
boolean state

ctrl->clk_stop_bus_reset = true;

Does this mean bus reset on exiting clock stop? or just that clock stop
is not supported and bus reset is required with complete re-enumeration.

WSA instances of SoundWire controllers do not support clk stop and a reset of ip is required with complete re-enumeration when a clock is cut off during suspend.


It would be good to try and explain using SoundWire 1.x terminology what
actions are taken on resume.

There are two cases here.

1> Controller Instance support ClockStop Mode0, we mostly use the generic core to do that except in resume path we make sure that we start the clock.

2> Controller Instances which that do not support ClockStop, we do soft reset of controller along with hard resetting slaves.


@@ -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->clk_stop_bus_reset = true;
+	} else {
+		ctrl->reg_read(ctrl, SWRM_COMP_MASTER_ID, &val);
+		if (val == MASTER_ID_WSA)
+			ctrl->clk_stop_bus_reset = true;
+	}

I think this means clock_stop_not_supported?

Yes It makes more sense to reword this to clock_stop_not_supported.



+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->clk_stop_bus_reset) {
+		reinit_completion(&ctrl->enumeration);
+		ctrl->reg_write(ctrl, SWRM_COMP_SW_RESET, 0x01);
+		qcom_swrm_get_device_status(ctrl);

don't you need some sort of delay before checking the controller and
device status? The bus reset sequence takes 4096 bits, that's a non-zero
time.

This is soft reset not full Bus Reset as WSA slaves have hard reset pins that will be toggled as part of suspend-resume.



+		sdw_handle_slave_status(&ctrl->bus, ctrl->status);
+		qcom_swrm_init(ctrl);
+		wait_for_completion_timeout(&ctrl->enumeration,
+					    msecs_to_jiffies(TIMEOUT_MS));
+	} 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");
+
+	usleep_range(300, 305);
+	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->clk_stop_bus_reset) {
+		/* 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) {

if a device has lost sync and reports -ENODATA, you want still want to
go ahead and not prevent the suspend operation from happening.

okay.


--srini

+		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 +1506,7 @@ 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);



[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux