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coresight: trbe: Allow driver to choose a different alignment

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The TRBE hardware mandates a minimum alignment for the TRBPTR_EL1,
advertised via the TRBIDR_EL1. This is used by the driver to
align the buffer write head. This patch allows the driver to
choose a different alignment from that of the hardware, by
decoupling the alignment tracking. This will be useful for
working around errata.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-9-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
This commit is contained in:
Suzuki K Poulose 2021-10-19 17:31:46 +01:00 committed by Mathieu Poirier
parent 2336a7b29b
commit e4bc8829a7
1 changed files with 15 additions and 3 deletions
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18
drivers/hwtracing/coresight/coresight-trbe.c
View file

@ -67,8 +67,18 @@ struct trbe_buf {
struct trbe_cpudata *cpudata;
};
/*
* struct trbe_cpudata: TRBE instance specific data
* @trbe_flag - TRBE dirty/access flag support
* @trbe_hw_align - Actual TRBE alignment required for TRBPTR_EL1.
* @trbe_align - Software alignment used for the TRBPTR_EL1.
* @cpu - CPU this TRBE belongs to.
* @mode - Mode of current operation. (perf/disabled)
* @drvdata - TRBE specific drvdata
*/
struct trbe_cpudata {
bool trbe_flag;
u64 trbe_hw_align;
u64 trbe_align;
int cpu;
enum cs_mode mode;
@ -875,7 +885,7 @@ static ssize_t align_show(struct device *dev, struct device_attribute *attr, cha
{
struct trbe_cpudata *cpudata = dev_get_drvdata(dev);
return sprintf(buf, "%llx\n", cpudata->trbe_align);
return sprintf(buf, "%llx\n", cpudata->trbe_hw_align);
}
static DEVICE_ATTR_RO(align);
@ -967,11 +977,13 @@ static void arm_trbe_probe_cpu(void *info)
goto cpu_clear;
}
cpudata->trbe_align = 1ULL << get_trbe_address_align(trbidr);
if (cpudata->trbe_align > SZ_2K) {
cpudata->trbe_hw_align = 1ULL << get_trbe_address_align(trbidr);
if (cpudata->trbe_hw_align > SZ_2K) {
pr_err("Unsupported alignment on cpu %d\n", cpu);
goto cpu_clear;
}
cpudata->trbe_align = cpudata->trbe_hw_align;
cpudata->trbe_flag = get_trbe_flag_update(trbidr);
cpudata->cpu = cpu;
cpudata->drvdata = drvdata;