coresight: etb: Allow etb to be built as a module

Allow to build coresight-etb10 as a module, for ease of development.

- Kconfig becomes a tristate, to allow =m
- add an etb_remove function, for module unload
- add a MODULE_DEVICE_TABLE for autoloading on boot

Cc: Mathieu Poirier <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Russell King <[email protected]>
Tested-by: Mike Leach <[email protected]>
Reviewed-by: Suzuki K Poulose <[email protected]>
Signed-off-by: Kim Phillips <[email protected]>
Signed-off-by: Tingwei Zhang <[email protected]>
Signed-off-by: Mathieu Poirier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

2 files changed, 29 insertions, 2 deletions

diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index d6e107bbd30b..996d84a1edb8 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -57,13 +57,16 @@ config CORESIGHT_SINK_TPIU
 	  the on-board coresight memory can handle.
 
 config CORESIGHT_SINK_ETBV10
-	bool "Coresight ETBv1.0 driver"
+	tristate "Coresight ETBv1.0 driver"
 	depends on CORESIGHT_LINKS_AND_SINKS
 	help
 	  This enables support for the Embedded Trace Buffer version 1.0 driver
 	  that complies with the generic implementation of the component without
 	  special enhancement or added features.
 
+	  To compile this driver as a module, choose M here: the
+	  module will be called coresight-etb10.
+
 config CORESIGHT_SOURCE_ETM3X
 	tristate "CoreSight Embedded Trace Macrocell 3.x driver"
 	depends on !ARM64
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 04ee9cda988d..248cc82c838e 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -801,6 +801,21 @@ err_misc_register:
 	return ret;
 }
 
+static int __exit etb_remove(struct amba_device *adev)
+{
+	struct etb_drvdata *drvdata = dev_get_drvdata(&adev->dev);
+
+	/*
+	 * Since misc_open() holds a refcount on the f_ops, which is
+	 * etb fops in this case, device is there until last file
+	 * handler to this device is closed.
+	 */
+	misc_deregister(&drvdata->miscdev);
+	coresight_unregister(drvdata->csdev);
+
+	return 0;
+}
+
 #ifdef CONFIG_PM
 static int etb_runtime_suspend(struct device *dev)
 {
@@ -835,6 +850,8 @@ static const struct amba_id etb_ids[] = {
 	{ 0, 0},
 };
 
+MODULE_DEVICE_TABLE(amba, etb_ids);
+
 static struct amba_driver etb_driver = {
 	.drv = {
 		.name	= "coresight-etb10",
@@ -844,6 +861,13 @@ static struct amba_driver etb_driver = {
 
 	},
 	.probe		= etb_probe,
+	.remove		= etb_remove,
 	.id_table	= etb_ids,
 };
-builtin_amba_driver(etb_driver);
+
+module_amba_driver(etb_driver);
+
+MODULE_AUTHOR("Pratik Patel <[email protected]>");
+MODULE_AUTHOR("Mathieu Poirier <[email protected]>");
+MODULE_DESCRIPTION("Arm CoreSight Embedded Trace Buffer driver");
+MODULE_LICENSE("GPL v2");