[PATCH v4 RESEND 2/3] coresight: Add support to get static id for system trace sources

[Mao Jinlong]

Dynamic trace id was introduced in coresight subsystem, so trace id is
allocated dynamically. However, some hardware ATB source has static trace
id and it cannot be changed via software programming. For such source,
it can call coresight_get_static_trace_id to get the fixed trace id from
device node and pass id to coresight_trace_id_get_static_system_id to
reserve the id.

Signed-off-by: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
---
 .../hwtracing/coresight/coresight-platform.c  | 26 +++++++++++++
 .../hwtracing/coresight/coresight-trace-id.c  | 38 ++++++++++++++-----
 .../hwtracing/coresight/coresight-trace-id.h  |  9 +++++
 include/linux/coresight.h                     |  1 +
 4 files changed, 64 insertions(+), 10 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index 64e171eaad82..703abf0fa3f9 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -183,6 +183,18 @@ static int of_coresight_get_cpu(struct device *dev)
 	return cpu;
 }
 
+/*
+ * of_coresight_get_trace_id: Get the atid of a source device.
+ *
+ * Returns 0 on success.
+ */
+static int of_coresight_get_static_trace_id(struct device *dev, u32 *id)
+{
+
+	return of_property_read_u32(dev->of_node, "arm,static-trace-id", id);
+}
+
+
 /*
  * of_coresight_parse_endpoint : Parse the given output endpoint @ep
  * and fill the connection information in @pdata->out_conns
@@ -317,6 +329,11 @@ static inline int of_coresight_get_cpu(struct device *dev)
 {
 	return -ENODEV;
 }
+
+static inline int of_coresight_get_static_trace_id(struct device *dev, u32 *id)
+{
+	return -ENODEV;
+}
 #endif
 
 #ifdef CONFIG_ACPI
@@ -796,6 +813,15 @@ int coresight_get_cpu(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(coresight_get_cpu);
 
+int coresight_get_static_trace_id(struct device *dev, u32 *id)
+{
+	if (!is_of_node(dev->fwnode))
+		return -EINVAL;
+
+	return of_coresight_get_static_trace_id(dev, id);
+}
+EXPORT_SYMBOL_GPL(coresight_get_static_trace_id);
+
 struct coresight_platform_data *
 coresight_get_platform_data(struct device *dev)
 {
diff --git a/drivers/hwtracing/coresight/coresight-trace-id.c b/drivers/hwtracing/coresight/coresight-trace-id.c
index af5b4ef59cea..ca3c3de4683e 100644
--- a/drivers/hwtracing/coresight/coresight-trace-id.c
+++ b/drivers/hwtracing/coresight/coresight-trace-id.c
@@ -11,6 +11,12 @@
 
 #include "coresight-trace-id.h"
 
+enum trace_id_flags {
+	TRACE_ID_ANY = 0x0,
+	TRACE_ID_PREFER_ODD = 0x1,
+	TRACE_ID_REQ_STATIC = 0x2,
+};
+
 /* Default trace ID map. Used on systems that don't require per sink mappings */
 static struct coresight_trace_id_map id_map_default;
 
@@ -80,16 +86,19 @@ static int coresight_trace_id_find_odd_id(struct coresight_trace_id_map *id_map)
  * Otherwise allocate next available ID.
  */
 static int coresight_trace_id_alloc_new_id(struct coresight_trace_id_map *id_map,
-					   int preferred_id, bool prefer_odd_id)
+					   int preferred_id, unsigned int flags)
 {
 	int id = 0;
 
 	/* for backwards compatibility, cpu IDs may use preferred value */
-	if (IS_VALID_CS_TRACE_ID(preferred_id) &&
-	    !test_bit(preferred_id, id_map->used_ids)) {
-		id = preferred_id;
-		goto trace_id_allocated;
-	} else if (prefer_odd_id) {
+	if (IS_VALID_CS_TRACE_ID(preferred_id)) {
+		if (!test_bit(preferred_id, id_map->used_ids)) {
+			id = preferred_id;
+			goto trace_id_allocated;
+		} else if (WARN((flags & TRACE_ID_REQ_STATIC), "Trace ID %d is used.\n",
+					preferred_id))
+			return -EINVAL;
+	} else if (flags & TRACE_ID_PREFER_ODD) {
 	/* may use odd ids to avoid preferred legacy cpu IDs */
 		id = coresight_trace_id_find_odd_id(id_map);
 		if (id)
@@ -175,7 +184,7 @@ static int coresight_trace_id_map_get_cpu_id(int cpu, struct coresight_trace_id_
 	 */
 	id = coresight_trace_id_alloc_new_id(id_map,
 					     CORESIGHT_LEGACY_CPU_TRACE_ID(cpu),
-					     false);
+					     TRACE_ID_ANY);
 	if (!IS_VALID_CS_TRACE_ID(id))
 		goto get_cpu_id_out_unlock;
 
@@ -222,14 +231,15 @@ static void coresight_trace_id_map_put_cpu_id(int cpu, struct coresight_trace_id
 	DUMP_ID_MAP(id_map);
 }
 
-static int coresight_trace_id_map_get_system_id(struct coresight_trace_id_map *id_map)
+static int coresight_trace_id_map_get_system_id(struct coresight_trace_id_map *id_map,
+					int preferred_id, unsigned int traceid_flags)
 {
 	unsigned long flags;
 	int id;
 
 	spin_lock_irqsave(&id_map_lock, flags);
 	/* prefer odd IDs for system components to avoid legacy CPU IDS */
-	id = coresight_trace_id_alloc_new_id(id_map, 0, true);
+	id = coresight_trace_id_alloc_new_id(id_map, preferred_id, traceid_flags);
 	spin_unlock_irqrestore(&id_map_lock, flags);
 
 	DUMP_ID(id);
@@ -271,10 +281,18 @@ EXPORT_SYMBOL_GPL(coresight_trace_id_read_cpu_id);
 
 int coresight_trace_id_get_system_id(void)
 {
-	return coresight_trace_id_map_get_system_id(&id_map_default);
+	return coresight_trace_id_map_get_system_id(&id_map_default, 0,
+			TRACE_ID_PREFER_ODD);
 }
 EXPORT_SYMBOL_GPL(coresight_trace_id_get_system_id);
 
+int coresight_trace_id_get_static_system_id(int trace_id)
+{
+	return coresight_trace_id_map_get_system_id(&id_map_default,
+			trace_id, TRACE_ID_REQ_STATIC);
+}
+EXPORT_SYMBOL_GPL(coresight_trace_id_get_static_system_id);
+
 void coresight_trace_id_put_system_id(int id)
 {
 	coresight_trace_id_map_put_system_id(&id_map_default, id);
diff --git a/drivers/hwtracing/coresight/coresight-trace-id.h b/drivers/hwtracing/coresight/coresight-trace-id.h
index 3797777d367e..ca2fdf31c835 100644
--- a/drivers/hwtracing/coresight/coresight-trace-id.h
+++ b/drivers/hwtracing/coresight/coresight-trace-id.h
@@ -122,6 +122,15 @@ int coresight_trace_id_read_cpu_id(int cpu);
  */
 int coresight_trace_id_get_system_id(void);
 
+/**
+ * Allocate a CoreSight static trace ID for a system component.
+ *
+ * Used to allocate static IDs for system trace sources such as dummy source.
+ *
+ * return: Trace ID or -EINVAL if allocation is impossible.
+ */
+int coresight_trace_id_get_static_system_id(int id);
+
 /**
  * Release an allocated system trace ID.
  *
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index f09ace92176e..2cdc0b1cd536 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -643,6 +643,7 @@ void coresight_relaxed_write64(struct coresight_device *csdev,
 void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset);
 
 extern int coresight_get_cpu(struct device *dev);
+extern int coresight_get_static_trace_id(struct device *dev, u32 *id);
 
 struct coresight_platform_data *coresight_get_platform_data(struct device *dev);
 struct coresight_connection *
-- 
2.46.0