[PATCH 5/5] perf/arm_cspmu: Add devicetree support
Robin Murphy
robin.murphy at arm.com
Thu Dec 7 01:43:10 PST 2023
On 2023-12-06 11:43 pm, Ilkka Koskinen wrote:
>
> Hi Robin,
>
> On Tue, 5 Dec 2023, Robin Murphy wrote:
>> Hook up devicetree probing support. For now let's hope that people
>> implement PMIIDR properly and we don't need an override mechanism.
>>
>> Signed-off-by: Robin Murphy <robin.murphy at arm.com>
>> ---
>> drivers/perf/arm_cspmu/arm_cspmu.c | 71 +++++++++++++++++++++++-------
>> 1 file changed, 56 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c
>> b/drivers/perf/arm_cspmu/arm_cspmu.c
>> index b64de4d800c7..80b5fc417ee3 100644
>> --- a/drivers/perf/arm_cspmu/arm_cspmu.c
>> +++ b/drivers/perf/arm_cspmu/arm_cspmu.c
>> @@ -27,6 +27,7 @@
>> #include <linux/io-64-nonatomic-lo-hi.h>
>> #include <linux/module.h>
>> #include <linux/mutex.h>
>> +#include <linux/of.h>
>> #include <linux/perf_event.h>
>> #include <linux/platform_device.h>
>>
>> @@ -309,6 +310,10 @@ static const char *arm_cspmu_get_name(const
>> struct arm_cspmu *cspmu)
>> static atomic_t pmu_idx[ACPI_APMT_NODE_TYPE_COUNT] = { 0 };
>>
>> dev = cspmu->dev;
>> + if (!has_acpi_companion(dev))
>
> Am I missing something since this doesn't work on top of v6.7-rc4?
> The problem I see is that has_acpi_companion() calls
> is_acpi_device_node(), which compares whether
>
> fwnode->ops == &acpi_device_fwnode_ops;
>
> However, the acpi/apmt code allocates fwnode by calling
> acpi_alloc_fwnode_static(), which assigns &acpi_static_fwnode_ops
> to ops.
Ah, I hadn't got as far as considering that has_acpi_companion() might
only work for namespace devices, but it makes sense now that you point
it out. I should have clarified that I don't have any suitable ACPI
system to test this on, and have only been able to verify basic DT
probing on an FPGA.
> I wonder though, if is_acpi_device_node() should check the static
> variant too? :/
Thanks for the tip, I'll look into that and try to come up with
something that works for a v2 (at worst there's always the traditional
assumption that !dev->of_node implies ACPI)
Cheers,
Robin.
>
> Cheers, Ilkka
>
>> + return devm_kasprintf(dev, GFP_KERNEL, PMUNAME "_%u",
>> + atomic_fetch_inc(&pmu_idx[0]));
>> +
>> apmt_node = arm_cspmu_apmt_node(dev);
>> pmu_type = apmt_node->type;
>>
>> @@ -406,7 +411,6 @@ static struct arm_cspmu_impl_match
>> *arm_cspmu_impl_match_get(u32 pmiidr)
>> static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)
>> {
>> int ret = 0;
>> - struct acpi_apmt_node *apmt_node = arm_cspmu_apmt_node(cspmu->dev);
>> struct arm_cspmu_impl_match *match;
>>
>> /* Start with a default PMU implementation */
>> @@ -425,8 +429,12 @@ static int arm_cspmu_init_impl_ops(struct
>> arm_cspmu *cspmu)
>> };
>>
>> /* Firmware may override implementer/product ID from PMIIDR */
>> - if (apmt_node->impl_id)
>> - cspmu->impl.pmiidr = apmt_node->impl_id;
>> + if (has_acpi_companion(cspmu->dev)) {
>> + struct acpi_apmt_node *apmt_node =
>> arm_cspmu_apmt_node(cspmu->dev);
>> +
>> + if (apmt_node->impl_id)
>> + cspmu->impl.pmiidr = apmt_node->impl_id;
>> + }
>>
>> /* Find implementer specific attribute ops. */
>> match = arm_cspmu_impl_match_get(cspmu->impl.pmiidr);
>> @@ -928,7 +936,6 @@ static void arm_cspmu_read(struct perf_event *event)
>>
>> static struct arm_cspmu *arm_cspmu_alloc(struct platform_device *pdev)
>> {
>> - struct acpi_apmt_node *apmt_node;
>> struct arm_cspmu *cspmu;
>> struct device *dev = &pdev->dev;
>>
>> @@ -939,8 +946,13 @@ static struct arm_cspmu *arm_cspmu_alloc(struct
>> platform_device *pdev)
>> cspmu->dev = dev;
>> platform_set_drvdata(pdev, cspmu);
>>
>> - apmt_node = arm_cspmu_apmt_node(dev);
>> - cspmu->has_atomic_dword = apmt_node->flags & ACPI_APMT_FLAGS_ATOMIC;
>> + if (has_acpi_companion(dev)) {
>> + struct acpi_apmt_node *apmt_node = arm_cspmu_apmt_node(dev);
>> +
>> + cspmu->has_atomic_dword = apmt_node->flags &
>> ACPI_APMT_FLAGS_ATOMIC;
>> + } else {
>> + cspmu->has_atomic_dword = device_property_read_bool(dev,
>> "arm,64-bit-atomic");
>> + }
>>
>> return cspmu;
>> }
>> @@ -1133,11 +1145,6 @@ static int arm_cspmu_acpi_get_cpus(struct
>> arm_cspmu *cspmu)
>> }
>> }
>>
>> - if (cpumask_empty(&cspmu->associated_cpus)) {
>> - dev_dbg(cspmu->dev, "No cpu associated with the PMU\n");
>> - return -ENODEV;
>> - }
>> -
>> return 0;
>> }
>> #else
>> @@ -1147,9 +1154,36 @@ static int arm_cspmu_acpi_get_cpus(struct
>> arm_cspmu *cspmu)
>> }
>> #endif
>>
>> +static int arm_cspmu_of_get_cpus(struct arm_cspmu *cspmu)
>> +{
>> + struct of_phandle_iterator it;
>> + int ret, cpu;
>> +
>> + of_for_each_phandle(&it, ret, cspmu->dev->of_node, "cpus", NULL,
>> 0) {
>> + cpu = of_cpu_node_to_id(it.node);
>> + if (cpu < 0)
>> + continue;
>> + cpumask_set_cpu(cpu, &cspmu->associated_cpus);
>> + }
>> + return ret;
>> +}
>> +
>> static int arm_cspmu_get_cpus(struct arm_cspmu *cspmu)
>> {
>> - return arm_cspmu_acpi_get_cpus(cspmu);
>> + int ret = 0;
>> +
>> + if (has_acpi_companion(cspmu->dev))
>> + ret = arm_cspmu_acpi_get_cpus(cspmu);
>> + else if (of_property_present(cspmu->dev->of_node, "cpus"))
>> + ret = arm_cspmu_of_get_cpus(cspmu);
>> + else
>> + cpumask_copy(&cspmu->associated_cpus, cpu_possible_mask);
>> +
>> + if (!ret && cpumask_empty(&cspmu->associated_cpus)) {
>> + dev_dbg(cspmu->dev, "No cpu associated with the PMU\n");
>> + ret = -ENODEV;
>> + }
>> + return ret;
>> }
>>
>> static int arm_cspmu_register_pmu(struct arm_cspmu *cspmu)
>> @@ -1246,11 +1280,18 @@ static const struct platform_device_id
>> arm_cspmu_id[] = {
>> };
>> MODULE_DEVICE_TABLE(platform, arm_cspmu_id);
>>
>> +static const struct of_device_id arm_cspmu_of_match[] = {
>> + { .compatible = "arm,coresight-pmu" },
>> + {}
>> +};
>> +MODULE_DEVICE_TABLE(of, arm_cspmu_of_match);
>> +
>> static struct platform_driver arm_cspmu_driver = {
>> .driver = {
>> - .name = DRVNAME,
>> - .suppress_bind_attrs = true,
>> - },
>> + .name = DRVNAME,
>> + .of_match_table = arm_cspmu_of_match,
>> + .suppress_bind_attrs = true,
>> + },
>> .probe = arm_cspmu_device_probe,
>> .remove = arm_cspmu_device_remove,
>> .id_table = arm_cspmu_id,
>> --
>> 2.39.2.101.g768bb238c484.dirty
>>
>>
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