Coresight platform support assumes that a missing "cpu" phandle
defaults to CPU0. This could be problematic and unnecessarily binds
components to CPU0, where they may not be. Let us make the DT binding
rules a bit stricter by not defaulting to CPU0 for missing "cpu"
affinity information.
Also in coresight etm and cpu-debug drivers, abort the probe
for such cases.
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
Documentation/devicetree/bindings/arm/coresight.txt | 2 +-
drivers/hwtracing/coresight/coresight-cpu-debug.c | 3 +++
drivers/hwtracing/coresight/coresight-etm3x.c | 3 +++
drivers/hwtracing/coresight/coresight-etm4x.c | 3 +++
drivers/hwtracing/coresight/coresight-platform.c | 10 +++++-----
5 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
index 8a88ddebc1a2..c4659ba9457d 100644
--- a/Documentation/devicetree/bindings/arm/coresight.txt
+++ b/Documentation/devicetree/bindings/arm/coresight.txt
@@ -88,7 +88,7 @@ its hardware characteristcs.
registers via co-processor 14.
* cpu: the cpu phandle this ETM/PTM is affined to. When omitted the
- source is considered to belong to CPU0.
+ affinity is set to invalid.
* Optional property for TMC:
diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c
index 07a1367c733f..58bfd6319f65 100644
--- a/drivers/hwtracing/coresight/coresight-cpu-debug.c
+++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c
@@ -579,6 +579,9 @@ static int debug_probe(struct amba_device *adev, const struct amba_id *id)
return -ENOMEM;
drvdata->cpu = coresight_get_cpu(dev);
+ if (drvdata->cpu < 0)
+ return drvdata->cpu;
+
if (per_cpu(debug_drvdata, drvdata->cpu)) {
dev_err(dev, "CPU%d drvdata has already been initialized\n",
drvdata->cpu);
diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index 225c2982e4fe..e2cb6873c3f2 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -816,6 +816,9 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id)
}
drvdata->cpu = coresight_get_cpu(dev);
+ if (drvdata->cpu < 0)
+ return drvdata->cpu;
+
desc.name = devm_kasprintf(dev, GFP_KERNEL, "etm%d", drvdata->cpu);
if (!desc.name)
return -ENOMEM;
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 7fe266194ab5..7bcac8896fc1 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -1101,6 +1101,9 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
spin_lock_init(&drvdata->spinlock);
drvdata->cpu = coresight_get_cpu(dev);
+ if (drvdata->cpu < 0)
+ return drvdata->cpu;
+
desc.name = devm_kasprintf(dev, GFP_KERNEL, "etm%d", drvdata->cpu);
if (!desc.name)
return -ENOMEM;
diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index 3c5ceda8db24..8b03fa573684 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -159,16 +159,16 @@ static int of_coresight_get_cpu(struct device *dev)
struct device_node *dn;
if (!dev->of_node)
- return 0;
+ return -ENODEV;
+
dn = of_parse_phandle(dev->of_node, "cpu", 0);
- /* Affinity defaults to CPU0 */
if (!dn)
- return 0;
+ return -ENODEV;
+
cpu = of_cpu_node_to_id(dn);
of_node_put(dn);
- /* Affinity to CPU0 if no cpu nodes are found */
- return (cpu < 0) ? 0 : cpu;
+ return cpu;
}
/*
--
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