From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Mathieu Poirier <mathieu.poirier@linaro.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Leo Yan <leo.yan@linaro.org>, Rob Herring <robh+dt@kernel.org>,
devicetree@vger.kernel.org,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Andy Gross <andy.gross@linaro.org>,
David Brown <david.brown@linaro.org>,
Mark Rutland <mark.rutland@arm.com>
Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
Rajendra Nayak <rnayak@codeaurora.org>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
Sibi Sankar <sibis@codeaurora.org>,
Vivek Gautam <vivek.gautam@codeaurora.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCHv3 1/1] coresight: Do not default to CPU0 for missing CPU phandle
Date: Mon, 24 Jun 2019 09:06:09 +0530 [thread overview]
Message-ID: <635466ab6a27781966bb083e93d2ca2729473ced.1561346998.git.saiprakash.ranjan@codeaurora.org> (raw)
In-Reply-To: <cover.1561346998.git.saiprakash.ranjan@codeaurora.org>
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@codeaurora.org>
---
.../bindings/arm/coresight-cpu-debug.txt | 4 ++--
.../devicetree/bindings/arm/coresight.txt | 8 +++++---
.../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 | 16 ++++++++--------
6 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/Documentation/devicetree/bindings/arm/coresight-cpu-debug.txt b/Documentation/devicetree/bindings/arm/coresight-cpu-debug.txt
index 298291211ea4..f1de3247c1b7 100644
--- a/Documentation/devicetree/bindings/arm/coresight-cpu-debug.txt
+++ b/Documentation/devicetree/bindings/arm/coresight-cpu-debug.txt
@@ -26,8 +26,8 @@ Required properties:
processor core is clocked by the internal CPU clock, so it
is enabled with CPU clock by default.
-- cpu : the CPU phandle the debug module is affined to. When omitted
- the module is considered to belong to CPU0.
+- cpu : the CPU phandle the debug module is affined to. Do not assume it
+ to default to CPU0 if omitted.
Optional properties:
diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
index 8a88ddebc1a2..fcc3bacfd8bc 100644
--- a/Documentation/devicetree/bindings/arm/coresight.txt
+++ b/Documentation/devicetree/bindings/arm/coresight.txt
@@ -59,6 +59,11 @@ its hardware characteristcs.
* port or ports: see "Graph bindings for Coresight" below.
+* Additional required property for Embedded Trace Macrocell (version 3.x and
+ version 4.x):
+ * cpu: the cpu phandle this ETM/PTM is affined to. Do not
+ assume it to default to CPU0 if omitted.
+
* Additional required properties for System Trace Macrocells (STM):
* reg: along with the physical base address and length of the register
set as described above, another entry is required to describe the
@@ -87,9 +92,6 @@ its hardware characteristcs.
* arm,cp14: must be present if the system accesses ETM/PTM management
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.
-
* Optional property for TMC:
* arm,buffer-size: size of contiguous buffer space for TMC ETR
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..4990da2c13e9 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;
}
/*
@@ -734,14 +734,14 @@ static int acpi_coresight_get_cpu(struct device *dev)
struct acpi_device *adev = ACPI_COMPANION(dev);
if (!adev)
- return 0;
+ return -ENODEV;
status = acpi_get_parent(adev->handle, &cpu_handle);
if (ACPI_FAILURE(status))
- return 0;
+ return -ENODEV;
cpu = acpi_handle_to_logical_cpuid(cpu_handle);
if (cpu >= nr_cpu_ids)
- return 0;
+ return -ENODEV;
return cpu;
}
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation
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next prev parent reply other threads:[~2019-06-24 3:36 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 3:36 [PATCHv3 0/1] coresight: Do not default to CPU0 for missing CPU phandle Sai Prakash Ranjan
2019-06-24 3:36 ` Sai Prakash Ranjan [this message]
2019-06-24 8:26 ` [PATCHv3 1/1] " Suzuki K Poulose
2019-06-24 9:27 ` Sai Prakash Ranjan
2019-06-26 17:41 ` Mathieu Poirier
2019-06-26 19:02 ` Sai Prakash Ranjan
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