Prevent sof module from being unloaded when a pcm is open

include/sound/soc.h

@@ -802,8 +802,13 @@ struct snd_soc_component_driver {
 	int probe_order;
 	int remove_order;
 
-	/* signal if the module handling the component cannot be removed */
-	unsigned int ignore_module_refcount:1;
+	/*
+	 * signal if the module handling the component should not be removed
+	 * if a pcm is open. Setting this would prevent the module
+	 * refcount being incremented in probe() but allow it be incremented
+	 * when a pcm is opened and decremented when it is closed.
+	 */
+	unsigned int module_get_upon_open:1;
 
 	/* bits */
 	unsigned int idle_bias_on:1;

sound/soc/intel/skylake/skl-pcm.c

@@ -1468,7 +1468,7 @@ static const struct snd_soc_component_driver skl_component  = {
 	.ops		= &skl_platform_ops,
 	.pcm_new	= skl_pcm_new,
 	.pcm_free	= skl_pcm_free,
-	.ignore_module_refcount = 1, /* do not increase the refcount in core */
+	.module_get_upon_open = 1, /* increment refcount when a pcm is opened */
 };
 
 int skl_platform_register(struct device *dev)

sound/soc/soc-core.c

@@ -947,7 +947,7 @@ static void soc_cleanup_component(struct snd_soc_component *component)
 	snd_soc_dapm_free(snd_soc_component_get_dapm(component));
 	soc_cleanup_component_debugfs(component);
 	component->card = NULL;
-	if (!component->driver->ignore_module_refcount)
+	if (!component->driver->module_get_upon_open)
 		module_put(component->dev->driver->owner);
 }
 
@@ -1381,7 +1381,7 @@ static int soc_probe_component(struct snd_soc_card *card,
 		return 0;
 	}
 
-	if (!component->driver->ignore_module_refcount &&
+	if (!component->driver->module_get_upon_open &&
 	    !try_module_get(component->dev->driver->owner))
 		return -ENODEV;
 

sound/soc/soc-pcm.c

@@ -15,6 +15,7 @@
 #include <linux/delay.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/pm_runtime.h>
+#include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 #include <linux/export.h>
@@ -463,6 +464,9 @@ static int soc_pcm_components_close(struct snd_pcm_substream *substream,
 			continue;
 
 		component->driver->ops->close(substream);
+
+		if (component->driver->module_get_upon_open)
+			module_put(component->dev->driver->owner);
 	}
 
 	return 0;
@@ -513,6 +517,10 @@ static int soc_pcm_open(struct snd_pcm_substream *substream)
 		    !component->driver->ops->open)
 			continue;
 
+		if (component->driver->module_get_upon_open &&
+		    !try_module_get(component->dev->driver->owner))
+			return -ENODEV;
+
 		ret = component->driver->ops->open(substream);
 		if (ret < 0) {
 			dev_err(component->dev,

sound/soc/sof/pcm.c

@@ -727,6 +727,6 @@ void snd_sof_new_platform_drv(struct snd_sof_dev *sdev)
 	pd->use_dai_pcm_id = true;
 	pd->topology_name_prefix = "sof";
 
-	 /* do not increase the refcount in core */
-	pd->ignore_module_refcount = 1;
+	 /* increment module refcount when a pcm is opened */
+	pd->module_get_upon_open = 1;
 }