soundwire: amd: add runtime pm ops for AMD SoundWire manager driver

Add support for runtime pm ops for AMD SoundWire manager driver.
Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
Signed-off-by: Mastan Katragadda <Mastan.Katragadda@amd.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/lkml/20230227154801.50319-7-Vijendar.Mukunda@amd.com
Link: https://lore.kernel.org/r/20230321050901.115439-7-Vijendar.Mukunda@amd.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/soundwire/amd_manager.c

@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/soundwire/sdw.h>
 #include <linux/soundwire/sdw_registers.h>
+#include <linux/pm_runtime.h>
 #include <linux/wait.h>
 #include <sound/pcm_params.h>
 #include <sound/soc.h>
@@ -133,6 +134,12 @@ static void amd_disable_sdw_interrupts(struct amd_sdw_manager *amd_manager)
 	writel(0x00, amd_manager->mmio + ACP_SW_ERROR_INTR_MASK);
 }
 
+static int amd_deinit_sdw_manager(struct amd_sdw_manager *amd_manager)
+{
+	amd_disable_sdw_interrupts(amd_manager);
+	return amd_disable_sdw_manager(amd_manager);
+}
+
 static void amd_sdw_set_frameshape(struct amd_sdw_manager *amd_manager)
 {
 	u32 frame_size;
@@ -866,6 +873,12 @@ static void amd_sdw_probe_work(struct work_struct *work)
 			return;
 		amd_sdw_set_frameshape(amd_manager);
 	}
+	/* Enable runtime PM */
+	pm_runtime_set_autosuspend_delay(amd_manager->dev, AMD_SDW_MASTER_SUSPEND_DELAY_MS);
+	pm_runtime_use_autosuspend(amd_manager->dev);
+	pm_runtime_mark_last_busy(amd_manager->dev);
+	pm_runtime_set_active(amd_manager->dev);
+	pm_runtime_enable(amd_manager->dev);
 }
 
 static int amd_sdw_manager_probe(struct platform_device *pdev)
@@ -953,17 +966,144 @@ static int amd_sdw_manager_remove(struct platform_device *pdev)
 {
 	struct amd_sdw_manager *amd_manager = dev_get_drvdata(&pdev->dev);
 
+	pm_runtime_disable(&pdev->dev);
 	cancel_work_sync(&amd_manager->probe_work);
 	amd_disable_sdw_interrupts(amd_manager);
 	sdw_bus_master_delete(&amd_manager->bus);
 	return amd_disable_sdw_manager(amd_manager);
 }
 
+static int amd_sdw_clock_stop(struct amd_sdw_manager *amd_manager)
+{
+	u32 val;
+	int ret;
+
+	ret = sdw_bus_prep_clk_stop(&amd_manager->bus);
+	if (ret < 0 && ret != -ENODATA) {
+		dev_err(amd_manager->dev, "prepare clock stop failed %d", ret);
+		return 0;
+	}
+	ret = sdw_bus_clk_stop(&amd_manager->bus);
+	if (ret < 0 && ret != -ENODATA) {
+		dev_err(amd_manager->dev, "bus clock stop failed %d", ret);
+		return 0;
+	}
+
+	ret = readl_poll_timeout(amd_manager->mmio + ACP_SW_CLK_RESUME_CTRL, val,
+				 (val & AMD_SDW_CLK_STOP_DONE), ACP_DELAY_US, AMD_SDW_TIMEOUT);
+	if (ret) {
+		dev_err(amd_manager->dev, "SDW%x clock stop failed\n", amd_manager->instance);
+		return 0;
+	}
+
+	amd_manager->clk_stopped = true;
+	if (amd_manager->wake_en_mask)
+		writel(0x01, amd_manager->acp_mmio + ACP_SW_WAKE_EN(amd_manager->instance));
+
+	dev_dbg(amd_manager->dev, "SDW%x clock stop successful\n", amd_manager->instance);
+	return 0;
+}
+
+static int amd_sdw_clock_stop_exit(struct amd_sdw_manager *amd_manager)
+{
+	int ret;
+	u32 val;
+
+	if (amd_manager->clk_stopped) {
+		val = readl(amd_manager->mmio + ACP_SW_CLK_RESUME_CTRL);
+		val |= AMD_SDW_CLK_RESUME_REQ;
+		writel(val, amd_manager->mmio + ACP_SW_CLK_RESUME_CTRL);
+		ret = readl_poll_timeout(amd_manager->mmio + ACP_SW_CLK_RESUME_CTRL, val,
+					 (val & AMD_SDW_CLK_RESUME_DONE), ACP_DELAY_US,
+					 AMD_SDW_TIMEOUT);
+		if (val & AMD_SDW_CLK_RESUME_DONE) {
+			writel(0, amd_manager->mmio + ACP_SW_CLK_RESUME_CTRL);
+			ret = sdw_bus_exit_clk_stop(&amd_manager->bus);
+			if (ret < 0)
+				dev_err(amd_manager->dev, "bus failed to exit clock stop %d\n",
+					ret);
+			amd_manager->clk_stopped = false;
+		}
+	}
+	if (amd_manager->clk_stopped) {
+		dev_err(amd_manager->dev, "SDW%x clock stop exit failed\n", amd_manager->instance);
+		return 0;
+	}
+	dev_dbg(amd_manager->dev, "SDW%x clock stop exit successful\n", amd_manager->instance);
+	return 0;
+}
+
+static int __maybe_unused amd_suspend_runtime(struct device *dev)
+{
+	struct amd_sdw_manager *amd_manager = dev_get_drvdata(dev);
+	struct sdw_bus *bus = &amd_manager->bus;
+	int ret;
+
+	if (bus->prop.hw_disabled) {
+		dev_dbg(bus->dev, "SoundWire manager %d is disabled,\n",
+			bus->link_id);
+		return 0;
+	}
+	if (amd_manager->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
+		return amd_sdw_clock_stop(amd_manager);
+	} else if (amd_manager->power_mode_mask & AMD_SDW_POWER_OFF_MODE) {
+		ret = amd_sdw_clock_stop(amd_manager);
+		if (ret)
+			return ret;
+		return amd_deinit_sdw_manager(amd_manager);
+	}
+	return 0;
+}
+
+static int __maybe_unused amd_resume_runtime(struct device *dev)
+{
+	struct amd_sdw_manager *amd_manager = dev_get_drvdata(dev);
+	struct sdw_bus *bus = &amd_manager->bus;
+	int ret;
+	u32 val;
+
+	if (bus->prop.hw_disabled) {
+		dev_dbg(bus->dev, "SoundWire manager %d is disabled, ignoring\n",
+			bus->link_id);
+		return 0;
+	}
+
+	if (amd_manager->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
+		return amd_sdw_clock_stop_exit(amd_manager);
+	} else if (amd_manager->power_mode_mask & AMD_SDW_POWER_OFF_MODE) {
+		val = readl(amd_manager->mmio + ACP_SW_CLK_RESUME_CTRL);
+		if (val) {
+			val |= AMD_SDW_CLK_RESUME_REQ;
+			writel(val, amd_manager->mmio + ACP_SW_CLK_RESUME_CTRL);
+			ret = readl_poll_timeout(amd_manager->mmio + ACP_SW_CLK_RESUME_CTRL, val,
+						 (val & AMD_SDW_CLK_RESUME_DONE), ACP_DELAY_US,
+						 AMD_SDW_TIMEOUT);
+			if (val & AMD_SDW_CLK_RESUME_DONE) {
+				writel(0, amd_manager->mmio + ACP_SW_CLK_RESUME_CTRL);
+				amd_manager->clk_stopped = false;
+			}
+		}
+		sdw_clear_slave_status(bus, SDW_UNATTACH_REQUEST_MASTER_RESET);
+		amd_init_sdw_manager(amd_manager);
+		amd_enable_sdw_interrupts(amd_manager);
+		ret = amd_enable_sdw_manager(amd_manager);
+		if (ret)
+			return ret;
+		amd_sdw_set_frameshape(amd_manager);
+	}
+	return 0;
+}
+
+static const struct dev_pm_ops amd_pm = {
+	SET_RUNTIME_PM_OPS(amd_suspend_runtime, amd_resume_runtime, NULL)
+};
+
 static struct platform_driver amd_sdw_driver = {
 	.probe	= &amd_sdw_manager_probe,
 	.remove = &amd_sdw_manager_remove,
 	.driver = {
 		.name	= "amd_sdw_manager",
+		.pm = &amd_pm,
 	}
 };
 module_platform_driver(amd_sdw_driver);

drivers/soundwire/amd_manager.h

@@ -186,6 +186,9 @@
 #define AMD_SDW0_PAD_KEEPER_DISABLE_MASK		0x1e
 #define AMD_SDW1_PAD_KEEPER_DISABLE_MASK		0xf
 #define AMD_SDW_PREQ_INTR_STAT				BIT(19)
+#define AMD_SDW_CLK_STOP_DONE				1
+#define AMD_SDW_CLK_RESUME_REQ				2
+#define AMD_SDW_CLK_RESUME_DONE				3
 
 static u32 amd_sdw_freq_tbl[AMD_SDW_MAX_FREQ_NUM] = {
 	AMD_SDW_DEFAULT_CLK_FREQ,

include/linux/soundwire/sdw_amd.h

@@ -8,6 +8,21 @@
 
 #include <linux/soundwire/sdw.h>
 
+/* AMD pm_runtime quirk definitions */
+
+/*
+ * Force the clock to stop(ClockStopMode0) when suspend callback
+ * is invoked.
+ */
+#define AMD_SDW_CLK_STOP_MODE		1
+
+/*
+ * Stop the bus when runtime suspend/system level suspend callback
+ * is invoked. If set, a complete bus reset and re-enumeration will
+ * be performed when the bus restarts. In-band wake interrupts are
+ * not supported in this mode.
+ */
+#define AMD_SDW_POWER_OFF_MODE		2
 #define ACP_SDW0	0
 #define ACP_SDW1	1
 
@@ -57,6 +72,7 @@ struct sdw_amd_dai_runtime {
  * @instance: SoundWire manager instance
  * @quirks: SoundWire manager quirks
  * @wake_en_mask: wake enable mask per SoundWire manager
+ * @clk_stopped: flag set to true when clock is stopped
  * @power_mode_mask: flag interprets amd SoundWire manager power mode
  * @dai_runtime_array: dai runtime array
  */
@@ -86,6 +102,7 @@ struct amd_sdw_manager {
 	u32 quirks;
 	u32 wake_en_mask;
 	u32 power_mode_mask;
+	bool clk_stopped;
 
 	struct sdw_amd_dai_runtime **dai_runtime_array;
 };