On 04/08/2023 10:18, Anshuman Khandual wrote:
On 8/3/23 19:25, Suzuki K Poulose wrote:
On 03/08/2023 06:56, Anshuman Khandual wrote:
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 | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index 7720619909d6..e1d9d06e7725 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -1494,9 +1494,9 @@ 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); + pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); + if (!pdata) + return -ENOMEM;
Please could you add a comment in here, on why we use a dummy platform data ? It is good to have documented it in the code too.
Sure, will add the following in-code documentation.
/** 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_dat()
minor nit: s/coresight_get_platform_dat/coresight_get_platform_data/ here and above in the description.
Otherwise, looks good.
Suzuki