[PATCH v3 3/4] ASoC: SDCA: Device boot into the system suspend process

[Charles Keepax <ckeepax@opensource.cirrus.com>]

When system suspending the device may be powered off, this means all
state will be lost and the firmware may need to be re-downloaded. Add
the necessary calls to bring the device back up. This also requires that
that the FDL (firmware download) IRQ handler is modified to allow it to
run before runtime PM has been fully restored.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

Changes since v2:
 - Correct detection of system suspend in FDL IRQ.

 sound/soc/sdca/sdca_class_function.c | 72 +++++++++++++++++++---------
 sound/soc/sdca/sdca_interrupts.c     | 17 +++++--
 2 files changed, 62 insertions(+), 27 deletions(-)

diff --git a/sound/soc/sdca/sdca_class_function.c b/sound/soc/sdca/sdca_class_function.c
index 7d0a6c0adbfb6..bbf486d9a3d07 100644
--- a/sound/soc/sdca/sdca_class_function.c
+++ b/sound/soc/sdca/sdca_class_function.c
@@ -211,21 +211,12 @@ static const struct snd_soc_component_driver class_function_component_drv = {
 	.endianness		= 1,
 };
 
-static int class_function_boot(struct class_function_drv *drv)
+static int class_function_init_device(struct class_function_drv *drv,
+				      unsigned int status)
 {
-	unsigned int reg = SDW_SDCA_CTL(drv->function->desc->adr,
-					SDCA_ENTITY_TYPE_ENTITY_0,
-					SDCA_CTL_ENTITY_0_FUNCTION_STATUS, 0);
-	unsigned int val;
 	int ret;
 
-	ret = regmap_read(drv->regmap, reg, &val);
-	if (ret < 0) {
-		dev_err(drv->dev, "failed to read function status: %d\n", ret);
-		return ret;
-	}
-
-	if (!(val & SDCA_CTL_ENTITY_0_FUNCTION_HAS_BEEN_RESET)) {
+	if (!(status & SDCA_CTL_ENTITY_0_FUNCTION_HAS_BEEN_RESET)) {
 		dev_dbg(drv->dev, "reset function device\n");
 
 		ret = sdca_reset_function(drv->dev, drv->function, drv->regmap);
@@ -233,24 +224,36 @@ static int class_function_boot(struct class_function_drv *drv)
 			return ret;
 	}
 
-	if (val & SDCA_CTL_ENTITY_0_FUNCTION_NEEDS_INITIALIZATION) {
+	if (status & SDCA_CTL_ENTITY_0_FUNCTION_NEEDS_INITIALIZATION) {
 		dev_dbg(drv->dev, "write initialisation\n");
 
 		ret = sdca_regmap_write_init(drv->dev, drv->core->dev_regmap,
 					     drv->function);
 		if (ret)
 			return ret;
+	}
 
-		ret = regmap_write(drv->regmap, reg,
-				   SDCA_CTL_ENTITY_0_FUNCTION_NEEDS_INITIALIZATION);
-		if (ret < 0) {
-			dev_err(drv->dev,
-				"failed to clear function init status: %d\n",
-				ret);
-			return ret;
-		}
+	return 0;
+}
+
+static int class_function_boot(struct class_function_drv *drv)
+{
+	unsigned int reg = SDW_SDCA_CTL(drv->function->desc->adr,
+					SDCA_ENTITY_TYPE_ENTITY_0,
+					SDCA_CTL_ENTITY_0_FUNCTION_STATUS, 0);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(drv->regmap, reg, &val);
+	if (ret < 0) {
+		dev_err(drv->dev, "failed to read function status: %d\n", ret);
+		return ret;
 	}
 
+	ret = class_function_init_device(drv, val);
+	if (ret)
+		return ret;
+
 	/* Start FDL process */
 	ret = sdca_irq_populate_early(drv->dev, drv->regmap, drv->function,
 				      drv->core->irq_info);
@@ -419,10 +422,35 @@ static int class_function_runtime_resume(struct device *dev)
 	regcache_cache_only(drv->regmap, false);
 
 	if (drv->suspended) {
+		unsigned int reg = SDW_SDCA_CTL(drv->function->desc->adr,
+						SDCA_ENTITY_TYPE_ENTITY_0,
+						SDCA_CTL_ENTITY_0_FUNCTION_STATUS, 0);
+		unsigned int val;
+
+		ret = regmap_read(drv->regmap, reg, &val);
+		if (ret < 0) {
+			dev_err(drv->dev, "failed to read function status: %d\n", ret);
+			goto err;
+		}
+
+		ret = class_function_init_device(drv, val);
+		if (ret)
+			goto err;
+
 		sdca_irq_enable_early(drv->function, drv->core->irq_info);
-		/* TODO: Add FDL process between early and late IRQs */
+
+		ret = sdca_fdl_sync(drv->dev, drv->function, drv->core->irq_info);
+		if (ret)
+			goto err;
+
 		sdca_irq_enable(drv->function, drv->core->irq_info);
 
+		ret = regmap_write(drv->regmap, reg, 0xFF);
+		if (ret < 0) {
+			dev_err(drv->dev, "failed to clear function status: %d\n", ret);
+			goto err;
+		}
+
 		drv->suspended = false;
 	}
 
diff --git a/sound/soc/sdca/sdca_interrupts.c b/sound/soc/sdca/sdca_interrupts.c
index afef7bbf613c9..cc40732c30ccb 100644
--- a/sound/soc/sdca/sdca_interrupts.c
+++ b/sound/soc/sdca/sdca_interrupts.c
@@ -205,10 +205,16 @@ static irqreturn_t fdl_owner_handler(int irq, void *data)
 	irqreturn_t irqret = IRQ_NONE;
 	int ret;
 
-	ret = pm_runtime_get_sync(dev);
-	if (ret < 0) {
-		dev_err(dev, "failed to resume for fdl: %d\n", ret);
-		goto error;
+	/*
+	 * FDL has to run from the system resume handler, at which point
+	 * we can't wait for the pm runtime.
+	 */
+	if (completion_done(&dev->power.completion)) {
+		ret = pm_runtime_get_sync(dev);
+		if (ret < 0) {
+			dev_err(dev, "failed to resume for fdl: %d\n", ret);
+			goto error;
+		}
 	}
 
 	ret = sdca_fdl_process(interrupt);
@@ -217,7 +223,8 @@ static irqreturn_t fdl_owner_handler(int irq, void *data)
 
 	irqret = IRQ_HANDLED;
 error:
-	pm_runtime_put(dev);
+	if (completion_done(&dev->power.completion))
+		pm_runtime_put(dev);
 	return irqret;
 }
 
-- 
2.47.3