Subject: [PATCH v3 08/20] coresight: allow etm4x to be built as a module

From: Tingwei Zhang <[email-masked]>
Date: Fri, 17 Jul 2020 13:45:24 +0800

From: Kim Phillips <[email-masked]>

Allow to build coresight-etm4x as a module, for ease of development.

- Kconfig becomes a tristate, to allow =m
- append -core to source file name to allow module to
  be called coresight-etm4x by the Makefile
- add an etm4_remove function, for module unload
- add a MODULE_DEVICE_TABLE for autoloading on boot

Cc: Mathieu Poirier <[email-masked]>
Cc: Leo Yan <[email-masked]>
Cc: Alexander Shishkin <[email-masked]>
Cc: Randy Dunlap <[email-masked]>
Cc: Suzuki K Poulose <[email-masked]>
Cc: Greg Kroah-Hartman <[email-masked]>
Cc: Russell King <[email-masked]>
Signed-off-by: Kim Phillips <[email-masked]>
Signed-off-by: Tingwei Zhang <[email-masked]>
---
 drivers/hwtracing/coresight/Kconfig           |  5 ++-
 drivers/hwtracing/coresight/Makefile          |  4 +--
 ...resight-etm4x.c => coresight-etm4x-core.c} | 31 ++++++++++++++++++-
 3 files changed, 36 insertions(+), 4 deletions(-)
 rename drivers/hwtracing/coresight/{coresight-etm4x.c => coresight-etm4x-core.c} (98%)

diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index 8fd9fd139cf3..d6e107bbd30b 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -78,7 +78,7 @@ config CORESIGHT_SOURCE_ETM3X
 	  module will be called coresight-etm3x.
 
 config CORESIGHT_SOURCE_ETM4X
-	bool "CoreSight Embedded Trace Macrocell 4.x driver"
+	tristate "CoreSight Embedded Trace Macrocell 4.x driver"
 	depends on ARM64
 	select CORESIGHT_LINKS_AND_SINKS
 	select PID_IN_CONTEXTIDR
@@ -88,6 +88,9 @@ config CORESIGHT_SOURCE_ETM4X
 	  for instruction level tracing. Depending on the implemented version
 	  data tracing may also be available.
 
+	  To compile this driver as a module, choose M here: the
+	  module will be called coresight-etm4x.
+
 config CORESIGHT_STM
 	tristate "CoreSight System Trace Macrocell driver"
 	depends on (ARM && !(CPU_32v3 || CPU_32v4 || CPU_32v4T)) || ARM64
diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
index d619cfd0abd8..271dc255454f 100644
--- a/drivers/hwtracing/coresight/Makefile
+++ b/drivers/hwtracing/coresight/Makefile
@@ -14,8 +14,8 @@ obj-$(CONFIG_CORESIGHT_LINKS_AND_SINKS) += coresight-funnel.o \
 obj-$(CONFIG_CORESIGHT_SOURCE_ETM3X) += coresight-etm3x.o
 coresight-etm3x-y := coresight-etm3x-core.o coresight-etm-cp14.o \
 					coresight-etm3x-sysfs.o
-obj-$(CONFIG_CORESIGHT_SOURCE_ETM4X) += coresight-etm4x.o \
-					coresight-etm4x-sysfs.o
+obj-$(CONFIG_CORESIGHT_SOURCE_ETM4X) += coresight-etm4x.o
+coresight-etm4x-y := coresight-etm4x-core.o coresight-etm4x-sysfs.o
 obj-$(CONFIG_CORESIGHT_STM) += coresight-stm.o
 obj-$(CONFIG_CORESIGHT_CPU_DEBUG) += coresight-cpu-debug.o
 obj-$(CONFIG_CORESIGHT_CATU) += coresight-catu.o
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
similarity index 98%
rename from drivers/hwtracing/coresight/coresight-etm4x.c
rename to drivers/hwtracing/coresight/coresight-etm4x-core.c
index 747afc875f91..b5945f62794c 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1536,6 +1536,26 @@ static struct amba_cs_uci_id uci_id_etm4[] = {
 	}
 };
 
+static int __exit etm4_remove(struct amba_device *adev)
+{
+	struct etmv4_drvdata *drvdata = dev_get_drvdata(&adev->dev);
+
+	etm_perf_symlink(drvdata->csdev, false);
+
+	if (--etm4_count == 0) {
+		etm4_cpu_pm_unregister();
+
+		cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);
+		if (hp_online)
+			cpuhp_remove_state_nocalls(hp_online);
+	}
+
+	coresight_unregister(drvdata->csdev);
+
+	return 0;
+}
+
+
 static const struct amba_id etm4_ids[] = {
 	CS_AMBA_ID(0x000bb95d),			/* Cortex-A53 */
 	CS_AMBA_ID(0x000bb95e),			/* Cortex-A57 */
@@ -1553,12 +1573,21 @@ static const struct amba_id etm4_ids[] = {
 	{},
 };
 
+MODULE_DEVICE_TABLE(amba, etm4_ids);
+
 static struct amba_driver etm4x_driver = {
 	.drv = {
 		.name   = "coresight-etm4x",
+		.owner  = THIS_MODULE,
 		.suppress_bind_attrs = true,
 	},
 	.probe		= etm4_probe,
+	.remove         = etm4_remove,
 	.id_table	= etm4_ids,
 };
-builtin_amba_driver(etm4x_driver);
+module_amba_driver(etm4x_driver);
+
+MODULE_AUTHOR("Pratik Patel <[email-masked]>");
+MODULE_AUTHOR("Mathieu Poirier <[email-masked]>");
+MODULE_DESCRIPTION("Arm CoreSight Program Flow Trace v4 driver");
+MODULE_LICENSE("GPL v2");
-- 
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a Linux Foundation Collaborative Project

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