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.
It would be good to try and explain using SoundWire 1.x terminology what
actions are taken on resume.
> @@ -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?
> +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.
> + 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.
> + 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);
