[RFC V3 2/3] arm_pmu: acpi: add support for CPU PMU variant detection
From: Agustin Vega-Frias <hidden>
Date: 2018-06-22 19:49:51
Also in:
linux-acpi, lkml
Subsystem:
acpi, arm pmu profiling and debugging, generic include/asm header files, the rest · Maintainers:
"Rafael J. Wysocki", Will Deacon, Mark Rutland, Arnd Bergmann, Linus Torvalds
DT allows CPU PMU variant detection via the PMU device compatible
property. ACPI does not have an equivalent mechanism so we introduce
a probe table to allow this via a device nested inside the CPU device
in the DSDT:
Device (CPU0)
{
Name (_HID, "ACPI0007" /* Processor Device */)
...
Device (PMU0)
{
Name (_HID, "QCOM8150") /* Qualcomm Falkor PMU device */
/*
* The device might also contain _DSD properties to indicate other
* IMPLEMENTATION DEFINED PMU features.
*/
Name (_DSD, Package ()
{
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package ()
{
...
}
})
}
}
With this in place we can declare the variant:
ACPI_DECLARE_PMU_VARIANT(qcom_falkor, "QCOM8150", falkor_pmu_init);
The init function is called after the default PMU initialization and is
passed a pointer to the arm_pmu structure and a pointer to the PMU device.
The init function can then override arm_pmu callbacks and attributes and
query more properties from the PMU device.
Signed-off-by: Agustin Vega-Frias <redacted>
---
drivers/perf/arm_pmu_acpi.c | 27 +++++++++++++++++++++++++++
include/asm-generic/vmlinux.lds.h | 1 +
include/linux/acpi.h | 11 +++++++++++
include/linux/perf/arm_pmu.h | 1 +
4 files changed, 40 insertions(+)
diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
index 0f19751..6b0ca71 100644
--- a/drivers/perf/arm_pmu_acpi.c
+++ b/drivers/perf/arm_pmu_acpi.c@@ -220,6 +220,26 @@ static int arm_pmu_acpi_cpu_starting(unsigned int cpu) return 0; } +/* + * Check if the given child device of the CPU device matches a PMU variant + * device declared with ACPI_DECLARE_PMU_VARIANT, if so, pass the arm_pmu + * structure and the matching device for further initialization. + */ +static int arm_pmu_variant_init(struct device *dev, void *data) +{ + extern struct acpi_device_id ACPI_PROBE_TABLE(pmu); + unsigned int cpu = *((unsigned int *)data); + const struct acpi_device_id *id; + + id = acpi_match_device(&ACPI_PROBE_TABLE(pmu), dev); + if (id) { + armpmu_acpi_init_fn fn = (armpmu_acpi_init_fn)id->driver_data; + + return fn(per_cpu(probed_pmus, cpu), dev); + } + return 0; +} + int arm_pmu_acpi_probe(armpmu_init_fn init_fn) { int pmu_idx = 0;
@@ -240,6 +260,7 @@ int arm_pmu_acpi_probe(armpmu_init_fn init_fn) */ for_each_possible_cpu(cpu) { struct arm_pmu *pmu = per_cpu(probed_pmus, cpu); + struct device *dev = get_cpu_device(cpu); char *base_name; if (!pmu || pmu->name)
@@ -254,6 +275,10 @@ int arm_pmu_acpi_probe(armpmu_init_fn init_fn) return ret; } + ret = device_for_each_child(dev, &cpu, arm_pmu_variant_init); + if (ret == -ENODEV) + pr_warn("Failed PMU re-init, fallback to plain PMUv3"); + base_name = pmu->name; pmu->name = kasprintf(GFP_KERNEL, "%s_%d", base_name, pmu_idx++); if (!pmu->name) {
@@ -290,3 +315,5 @@ static int arm_pmu_acpi_init(void) return ret; } subsys_initcall(arm_pmu_acpi_init) + +ACPI_DECLARE_PMU_SENTINEL();
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 5894049..f1be62a 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h@@ -600,6 +600,7 @@ IRQCHIP_OF_MATCH_TABLE() \ ACPI_PROBE_TABLE(irqchip) \ ACPI_PROBE_TABLE(timer) \ + ACPI_PROBE_TABLE(pmu) \ EARLYCON_TABLE() #define INIT_TEXT \
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 15bfb15..9c410cf 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h@@ -1153,6 +1153,17 @@ struct acpi_probe_entry { (&ACPI_PROBE_TABLE_END(t) - \ &ACPI_PROBE_TABLE(t))); \ }) + +#define ACPI_DECLARE_PMU_VARIANT(name, hid, init_fn) \ + static const struct acpi_device_id __acpi_probe_##name \ + __used __section(__pmu_acpi_probe_table) \ + = { .id = hid, .driver_data = (kernel_ulong_t)init_fn } + +#define ACPI_DECLARE_PMU_SENTINEL() \ + static const struct acpi_device_id __acpi_probe_sentinel \ + __used __section(__pmu_acpi_probe_table_end) \ + = { .id = "", .driver_data = 0 } + #else static inline int acpi_dev_get_property(struct acpi_device *adev, const char *name, acpi_object_type type,
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 40036a5..ff43d65 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h@@ -123,6 +123,7 @@ int armpmu_map_event(struct perf_event *event, u32 raw_event_mask); typedef int (*armpmu_init_fn)(struct arm_pmu *); +typedef int (*armpmu_acpi_init_fn)(struct arm_pmu *, struct device *); struct pmu_probe_info { unsigned int cpuid;
--
Qualcomm Datacenter Technologies, Inc. on behalf of the Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.