[RFC PATCH 3/8] coresight: syscfg: Example CoreSight configuration loadable module

[Mike Leach]

An example of creating a loadable module to add CoreSight configurations
into a system.

In the Kernel samples/coresight directory.

Signed-off-by: Mike Leach <mike.leach at linaro.org>
---
 MAINTAINERS                              |  1 +
 samples/Kconfig                          |  9 +++
 samples/Makefile                         |  1 +
 samples/coresight/Makefile               |  4 ++
 samples/coresight/coresight-cfg-sample.c | 73 ++++++++++++++++++++++++
 5 files changed, 88 insertions(+)
 create mode 100644 samples/coresight/Makefile
 create mode 100644 samples/coresight/coresight-cfg-sample.c

diff --git a/MAINTAINERS b/MAINTAINERS
index bd7aff0c120f..9ff5f5e7dd06 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1789,6 +1789,7 @@ F:	Documentation/trace/coresight/*
 F:	drivers/hwtracing/coresight/*
 F:	include/dt-bindings/arm/coresight-cti-dt.h
 F:	include/linux/coresight*
+F:	samples/coresight/*
 F:	tools/perf/arch/arm/util/auxtrace.c
 F:	tools/perf/arch/arm/util/cs-etm.c
 F:	tools/perf/arch/arm/util/cs-etm.h
diff --git a/samples/Kconfig b/samples/Kconfig
index b5a1a7aa7e23..0cd618e15571 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -223,4 +223,13 @@ config SAMPLE_WATCH_QUEUE
 	  Build example userspace program to use the new mount_notify(),
 	  sb_notify() syscalls and the KEYCTL_WATCH_KEY keyctl() function.
 
+config SAMPLE_CORESIGHT_SYSCFG
+	tristate "Build example loadable module for CoreSight config"
+	depends on CORESIGHT && m
+	help
+	  Build an example loadable module that adds new CoreSight features
+	  and configuration using the CoreSight system configuration API.
+	  This demonstrates how a user may create their own CoreSight
+	  configurations and easily load them into the system at runtime.
+
 endif # SAMPLES
diff --git a/samples/Makefile b/samples/Makefile
index 087e0988ccc5..6c96297001a8 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_SAMPLE_INTEL_MEI)		+= mei/
 subdir-$(CONFIG_SAMPLE_WATCHDOG)	+= watchdog
 subdir-$(CONFIG_SAMPLE_WATCH_QUEUE)	+= watch_queue
 obj-$(CONFIG_DEBUG_KMEMLEAK_TEST)	+= kmemleak/
+obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG)	+= coresight/
diff --git a/samples/coresight/Makefile b/samples/coresight/Makefile
new file mode 100644
index 000000000000..09126aabf43d
--- /dev/null
+++ b/samples/coresight/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG) += coresight-cfg-sample.o
+ccflags-y += -I$(src)/../../drivers/hwtracing/coresight
diff --git a/samples/coresight/coresight-cfg-sample.c b/samples/coresight/coresight-cfg-sample.c
new file mode 100644
index 000000000000..865c188fae34
--- /dev/null
+++ b/samples/coresight/coresight-cfg-sample.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(C) 2020 Linaro Limited. All rights reserved.
+ * Author: Mike Leach <mike.leach at linaro.org>
+ */
+
+#include "coresight-config.h"
+#include "coresight-syscfg.h"
+
+/* create an alternate autofdo configuration */
+
+/* we will provide 4 sets of preset parameter values */
+#define AFDO2_NR_PRESETS	4
+/* the total number of parameters in used features - strobing has 2 */
+#define AFDO2_NR_PARAM_SUM	2
+
+static const char *afdo2_ref_names[] = {
+	"strobing",
+};
+
+/*
+ * set of presets leaves strobing window constant while varying period to allow
+ * experimentation with mark / space ratios for various workloads
+ */
+static u64 afdo2_presets[AFDO2_NR_PRESETS][AFDO2_NR_PARAM_SUM] = {
+	{ 1000, 100 },
+	{ 1000, 1000 },
+	{ 1000, 5000 },
+	{ 1000, 10000 },
+};
+
+struct cscfg_config_desc afdo2 = {
+	.name = "autofdo2",
+	.description = "Setup ETMs with strobing for autofdo\n"
+	"Supplied presets allow experimentation with mark-space ratio for various loads\n",
+	.nr_feat_refs = ARRAY_SIZE(afdo2_ref_names),
+	.feat_ref_names = afdo2_ref_names,
+	.nr_presets = AFDO2_NR_PRESETS,
+	.nr_total_params = AFDO2_NR_PARAM_SUM,
+	.presets = &afdo2_presets[0][0],
+};
+
+static struct cscfg_feature_desc *sample_feats[] = {
+	0
+};
+
+static struct cscfg_config_desc *sample_cfgs[] = {
+	&afdo2,
+	0
+};
+
+static struct cscfg_load_owner_info mod_owner = {
+	.type = CSCFG_OWNER_MODULE,
+	.owner_handle = THIS_MODULE,
+};
+
+/* module init and exit - just load and unload configs */
+static int __init cscfg_sample_init(void)
+{
+	return cscfg_load_config_sets(sample_cfgs, sample_feats, &mod_owner);
+}
+
+static void __exit cscfg_sample_exit(void)
+{
+	cscfg_unload_config_sets(&mod_owner);
+}
+
+module_init(cscfg_sample_init);
+module_exit(cscfg_sample_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Mike Leach <mike.leach at linaro.org>");
+MODULE_DESCRIPTION("CoreSight Syscfg Example");
-- 
2.17.1