From mboxrd@z Thu Jan 1 00:00:00 1970 From: nhillery@codeaurora.org (Nathan Hillery) Date: Tue, 21 Aug 2018 17:44:59 -0400 Subject: [RFC, V5, 2/4] arm_pmu: acpi: Add support for CPU PMU variant detection In-Reply-To: <1534887901-24734-1-git-send-email-nhillery@codeaurora.org> References: <1534887901-24734-1-git-send-email-nhillery@codeaurora.org> Message-ID: <1534887901-24734-3-git-send-email-nhillery@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Device Tree 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 support detection 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 & attributes and query more properties from the PMU device. Signed-off-by: Nathan Hillery --- 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 af24057..ac794b9d 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -599,6 +599,7 @@ 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 a6a7ae8..ba2403a 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -1156,6 +1156,17 @@ 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 as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.