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SubjectRe: [PATCH V3 2/4] arm_pmu: acpi: Add a representative platform device for TRBE
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On 2023/8/3 13:56, Anshuman Khandual wrote:
> ACPI TRBE does not have a HID for identification which could create and add
> a platform device into the platform bus. Also without a platform device, it
> cannot be probed and bound to a platform driver.
>
> This creates a dummy platform device for TRBE after ascertaining that ACPI
> provides required interrupts uniformly across all cpus on the system. This
> device gets created inside drivers/perf/arm_pmu_acpi.c to accommodate TRBE
> being built as a module.
>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> arch/arm64/include/asm/acpi.h | 3 +++
> drivers/perf/arm_pmu_acpi.c | 37 ++++++++++++++++++++++++++++++++++-
> include/linux/perf/arm_pmu.h | 1 +
> 3 files changed, 40 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> index bd68e1b7f29f..4d537d56eb84 100644
> --- a/arch/arm64/include/asm/acpi.h
> +++ b/arch/arm64/include/asm/acpi.h
> @@ -42,6 +42,9 @@
> #define ACPI_MADT_GICC_SPE (offsetof(struct acpi_madt_generic_interrupt, \
> spe_interrupt) + sizeof(u16))
>
> +#define ACPI_MADT_GICC_TRBE (offsetof(struct acpi_madt_generic_interrupt, \
> + trbe_interrupt) + sizeof(u16))
> +
> /* Basic configuration for ACPI */
> #ifdef CONFIG_ACPI
> pgprot_t __acpi_get_mem_attribute(phys_addr_t addr);
> diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
> index 235c14766a36..79feea548e6e 100644
> --- a/drivers/perf/arm_pmu_acpi.c
> +++ b/drivers/perf/arm_pmu_acpi.c
> @@ -69,7 +69,7 @@ static void arm_pmu_acpi_unregister_irq(int cpu)
> acpi_unregister_gsi(gsi);
> }
>
> -#if IS_ENABLED(CONFIG_ARM_SPE_PMU)
> +#if IS_ENABLED(CONFIG_ARM_SPE_PMU) || IS_ENABLED(CONFIG_CORESIGHT_TRBE)
> static int
> arm_acpi_register_pmu_device(struct platform_device *pdev, u8 len,
> u16 (*parse_gsi)(struct acpi_madt_generic_interrupt *))
> @@ -166,6 +166,40 @@ static inline void arm_spe_acpi_register_device(void)
> }
> #endif /* CONFIG_ARM_SPE_PMU */
>
> +#ifdef CONFIG_CORESIGHT_TRBE

Maybe we should use #if IS_ENABLED(CONFIG_CORESIGHT_TRBE) here and other places?

As trbe can be configured as a module, when CONFIG_CORESIGHT_TRBE=m this block
won't be compiled. Referred to

https://github.com/torvalds/linux/blob/c7c90e121e992eefdf07945e5a6e9cf097b29463/include/linux/kconfig.h#L68

> +static struct resource trbe_resources[] = {
> + {
> + /* irq */
> + .flags = IORESOURCE_IRQ,
> + }
> +};
> +
> +static struct platform_device trbe_dev = {
> + .name = ARMV8_TRBE_PDEV_NAME,
> + .id = -1,
> + .resource = trbe_resources,
> + .num_resources = ARRAY_SIZE(trbe_resources)
> +};
> +
> +static u16 arm_trbe_parse_gsi(struct acpi_madt_generic_interrupt *gicc)
> +{
> + return gicc->trbe_interrupt;
> +}
> +
> +static void arm_trbe_acpi_register_device(void)
> +{
> + int ret = arm_acpi_register_pmu_device(&trbe_dev, ACPI_MADT_GICC_TRBE,
> + arm_trbe_parse_gsi);
> + if (ret)
> + pr_warn("ACPI: TRBE: Unable to register device\n");
> +}
> +#else
> +static inline void arm_trbe_acpi_register_device(void)
> +{
> +
> +}
> +#endif /* CONFIG_CORESIGHT_TRBE */
> +
> static int arm_pmu_acpi_parse_irqs(void)
> {
> int irq, cpu, irq_cpu, err;
> @@ -401,6 +435,7 @@ static int arm_pmu_acpi_init(void)
> return 0;
>
> arm_spe_acpi_register_device();
> + arm_trbe_acpi_register_device();
>
> return 0;
> }
> diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
> index a0801f68762b..143fbc10ecfe 100644
> --- a/include/linux/perf/arm_pmu.h
> +++ b/include/linux/perf/arm_pmu.h
> @@ -187,5 +187,6 @@ void armpmu_free_irq(int irq, int cpu);
> #endif /* CONFIG_ARM_PMU */
>
> #define ARMV8_SPE_PDEV_NAME "arm,spe-v1"
> +#define ARMV8_TRBE_PDEV_NAME "arm,trbe"
>
> #endif /* __ARM_PMU_H__ */
>

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