Hi James,
On 2024/5/16 21:23, James Clark wrote:
On 16/05/2024 04:56, Mao Jinlong wrote:
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. Reserve trace id for this kind of hardware source.
Signed-off-by: Mao Jinlong quic_jinlmao@quicinc.com
.../hwtracing/coresight/coresight-platform.c | 26 +++++++++++++++++++ .../hwtracing/coresight/coresight-trace-id.c | 24 +++++++++++++++++ .../hwtracing/coresight/coresight-trace-id.h | 11 ++++++++ include/linux/coresight.h | 1 + 4 files changed, 62 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c index 9d550f5697fa..d3e22a2608df 100644 --- a/drivers/hwtracing/coresight/coresight-platform.c +++ b/drivers/hwtracing/coresight/coresight-platform.c @@ -183,6 +183,17 @@ 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_trace_id(struct device *dev, u32 *id) +{
- return of_property_read_u32(dev->of_node, "trace-id", id);
+}
- /*
- of_coresight_parse_endpoint : Parse the given output endpoint @ep
- and fill the connection information in @pdata->out_conns
@@ -315,6 +326,12 @@ static inline int of_coresight_get_cpu(struct device *dev) { return -ENODEV; }
+static int of_coresight_get_trace_id(struct device *dev, u32 *id) +{
- return -ENODEV;
+}
- #endif
#ifdef CONFIG_ACPI @@ -794,6 +811,15 @@ int coresight_get_cpu(struct device *dev) } EXPORT_SYMBOL_GPL(coresight_get_cpu); +int coresight_get_trace_id(struct device *dev, u32 *id) +{
- if (!is_of_node(dev->fwnode))
return -EINVAL;- return of_coresight_get_trace_id(dev, id);
+} +EXPORT_SYMBOL_GPL(coresight_get_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..536a34e9de6f 100644 --- a/drivers/hwtracing/coresight/coresight-trace-id.c +++ b/drivers/hwtracing/coresight/coresight-trace-id.c @@ -110,6 +110,24 @@ static int coresight_trace_id_alloc_new_id(struct coresight_trace_id_map *id_map return id; } +static int coresight_trace_id_set(int id, struct coresight_trace_id_map *id_map) +{
- unsigned long flags;
- spin_lock_irqsave(&id_map_lock, flags);
- if (WARN(!IS_VALID_CS_TRACE_ID(id), "Invalid Trace ID %d\n", id))
return -EINVAL;- if (WARN(test_bit(id, id_map->used_ids), "ID is already used: %d\n", id))
return -EINVAL;Do these returns not skip unlocking the spinlock?
Yes. Missing the unlocking the spinlock here.
It might be slightly fewer changes if we update the existing coresight_trace_id_alloc_new_id() to add a new "only_preferred" option.
Then use the existing system id allocator which already handles the lock and unlock properly:
static int coresight_trace_id_map_get_system_id(struct coresight_trace_id_map *id_map, int id,
bool only_preferred){ ... 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, id, true, only_preferred); spin_unlock_irqrestore(&id_map_lock, flags); ...
I suppose the end result is the same as your implementation, but it trades making one existing function slightly more complicated instead of adding some new ones.
yes. Your suggestion looks better. I will think carefully.