linux-kernel - [RFC 10/11] coresgith: etm-perf: Connect TRBE sink with ETE source

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Message-Id: <1605012309-24812-11-git-send-email-anshuman.khandual@arm.com>
Date:   Tue, 10 Nov 2020 18:15:08 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     linux-arm-kernel@...ts.infradead.org, coresight@...ts.linaro.org
Cc:     linux-kernel@...r.kernel.org, suzuki.poulose@....com,
        mathieu.poirier@...aro.org, mike.leach@...aro.org,
        Anshuman Khandual <anshuman.khandual@....com>
Subject: [RFC 10/11] coresgith: etm-perf: Connect TRBE sink with ETE source

Unlike traditional sink devices, individual TRBE instances are not detected
via DT or ACPI nodes. Instead TRBE instances are detected during CPU online
process. Hence a path connecting ETE and TRBE on a given CPU would not have
been established until then. This adds two coresight helpers that will help
modify outward connections from a source device to establish and terminate
path to a given sink device. But this method might not be optimal and would
be reworked later.

Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
 drivers/hwtracing/coresight/coresight-etm-perf.c | 30 ++++++++++++++++++++++++
 drivers/hwtracing/coresight/coresight-etm-perf.h |  4 ++++
 drivers/hwtracing/coresight/coresight-platform.c |  3 ++-
 drivers/hwtracing/coresight/coresight-trbe.c     |  2 ++
 include/linux/coresight.h                        |  2 ++
 5 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 1a37991..b4ab1d4 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -664,3 +664,33 @@ void __exit etm_perf_exit(void)
 {
 	perf_pmu_unregister(&etm_pmu);
 }
+
+#ifdef CONFIG_CORESIGHT_TRBE
+void coresight_trbe_connect_ete(struct coresight_device *csdev_trbe, int cpu)
+{
+	struct coresight_device *csdev_ete = per_cpu(csdev_src, cpu);
+
+	if (!csdev_ete) {
+		pr_err("Corresponding ETE device not present on cpu %d\n", cpu);
+		return;
+	}
+	csdev_ete->def_sink = csdev_trbe;
+	csdev_ete->pdata->nr_outport++;
+	if (!csdev_ete->pdata->conns)
+		coresight_alloc_conns(&csdev_ete->dev, csdev_ete->pdata);
+	csdev_ete->pdata->conns[csdev_ete->pdata->nr_outport - 1].child_dev = csdev_trbe;
+}
+
+void coresight_trbe_remove_ete(struct coresight_device *csdev_trbe, int cpu)
+{
+	struct coresight_device *csdev_ete = per_cpu(csdev_src, cpu);
+
+	if (!csdev_ete) {
+		pr_err("Corresponding ETE device not present on cpu %d\n", cpu);
+		return;
+	}
+	csdev_ete->pdata->conns[csdev_ete->pdata->nr_outport - 1].child_dev = NULL;
+	csdev_ete->def_sink = NULL;
+	csdev_ete->pdata->nr_outport--;
+}
+#endif
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.h b/drivers/hwtracing/coresight/coresight-etm-perf.h
index 3e4f2ad..20386cf 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.h
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.h
@@ -85,4 +85,8 @@ static inline void *etm_perf_sink_config(struct perf_output_handle *handle)
 int __init etm_perf_init(void);
 void __exit etm_perf_exit(void);
 
+#ifdef CONFIG_CORESIGHT_TRBE
+void coresight_trbe_connect_ete(struct coresight_device *csdev, int cpu);
+void coresight_trbe_remove_ete(struct coresight_device *csdev, int cpu);
+#endif
 #endif
diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index c594f45..8fa7406 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -23,7 +23,7 @@
  * coresight_alloc_conns: Allocate connections record for each output
  * port from the device.
  */
-static int coresight_alloc_conns(struct device *dev,
+int coresight_alloc_conns(struct device *dev,
 				 struct coresight_platform_data *pdata)
 {
 	if (pdata->nr_outport) {
@@ -35,6 +35,7 @@ static int coresight_alloc_conns(struct device *dev,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(coresight_alloc_conns);
 
 static struct device *
 coresight_find_device_by_fwnode(struct fwnode_handle *fwnode)
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 48a8ec3..afd1a1c 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -507,6 +507,7 @@ static void arm_trbe_probe_coresight_cpu(void *info)
 	if (IS_ERR(cpudata->csdev))
 		goto cpu_clear;
 
+	coresight_trbe_connect_ete(cpudata->csdev, cpudata->cpu);
 	dev_set_drvdata(&cpudata->csdev->dev, cpudata);
 	cpudata->trbe_dbm = get_trbe_flag_update();
 	cpudata->trbe_align = 1ULL << get_trbe_address_align();
@@ -586,6 +587,7 @@ static int arm_trbe_cpu_teardown(unsigned int cpu, struct hlist_node *node)
 
 	if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
 		cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
+		coresight_trbe_remove_ete(cpudata->csdev, cpu);
 		if (cpudata->csdev) {
 			coresight_unregister(cpudata->csdev);
 			cpudata->drvdata = NULL;
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index c2d0a2a..c657813 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -496,6 +496,8 @@ void coresight_relaxed_write64(struct coresight_device *csdev,
 			       u64 val, u32 offset);
 void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset);
 
+int coresight_alloc_conns(struct device *dev,
+			  struct coresight_platform_data *pdata);
 
 #else
 static inline struct coresight_device *
-- 
2.7.4