[PATCH V4 3/4] coresight: trbe: Add a representative coresight_platform_data for TRBE

Anshuman Khandual
2023-08-08T08:23:44Z

TRBE coresight devices do not need regular connections information, as the
paths get built between all percpu source and their respective percpu sink
devices. Please refer 'commit 2cd87a7b293d ("coresight: core: Add support
for dedicated percpu sinks")' which added support for percpu sink devices.

coresight_register() expect device connections via the platform_data. TRBE
devices do not have any graph connections and thus is empty. With upcoming
ACPI support for TRBE, we do not get a real acpi_device and thus
coresight_get_platform_dat() will end up in failures. Hence this allocates
a zeroed coresight_platform_data structure and assigns that back into the
device.

Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
drivers/hwtracing/coresight/coresight-trbe.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 7720619909d6..9455d62ca620 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -1494,9 +1494,20 @@ static int arm_trbe_device_probe(struct platform_device *pdev)
if (!drvdata)
return -ENOMEM;

- pdata = coresight_get_platform_data(dev);
- if (IS_ERR(pdata))
- return PTR_ERR(pdata);
+ /*
+ * TRBE coresight devices do not need regular connections
+ * information, as the paths get built between all percpu
+ * source and their respective percpu sink devices. Though
+ * coresight_register() expect device connections via the
+ * platform_data, which TRBE devices do not have. As they
+ * are not real ACPI devices, coresight_get_platform_data()
+ * ends up failing. Instead let's allocate a dummy zeroed
+ * coresight_platform_data structure and assign that back
+ * into the device for that purpose.
+ */
+ pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return -ENOMEM;

dev_set_drvdata(dev, drvdata);
dev->platform_data = pdata;
--
2.25.1