On Fri, Jun 14, 2019 at 08:09:09PM -0500, Jeremy Linton wrote:
> ACPI 6.3 adds additional fields to the MADT GICC
> structure to describe SPE PPI's. We pick these out
> of the cached reference to the madt_gicc structure
> similarly to the core PMU code. We then create a platform
> device referring to the IRQ and let the user/module loader
> decide whether to load the SPE driver.
>
> Signed-off-by: Jeremy Linton <jeremy.lin...@arm.com>
> ---
> arch/arm64/include/asm/acpi.h | 3 ++
> drivers/perf/arm_pmu_acpi.c | 75 +++++++++++++++++++++++++++++++++++
> include/linux/perf/arm_pmu.h | 2 +
> 3 files changed, 80 insertions(+)
>
> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> index 7628efbe6c12..d10399b9f998 100644
> --- a/arch/arm64/include/asm/acpi.h
> +++ b/arch/arm64/include/asm/acpi.h
> @@ -41,6 +41,9 @@
> (!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \
> (unsigned long)(entry) + (entry)->header.length > (end))
>
> +#define ACPI_MADT_GICC_SPE (ACPI_OFFSET(struct acpi_madt_generic_interrupt,
> \
> + spe_interrupt) + sizeof(u16))
> +
Nit: Do we really need this to be in a header file ?
> /* 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 0f197516d708..f5df100bc4f4 100644
> --- a/drivers/perf/arm_pmu_acpi.c
> +++ b/drivers/perf/arm_pmu_acpi.c
> @@ -74,6 +74,79 @@ static void arm_pmu_acpi_unregister_irq(int cpu)
> acpi_unregister_gsi(gsi);
> }
>
> +#if IS_ENABLED(CONFIG_ARM_SPE_PMU)
> +static struct resource spe_resources[] = {
> + {
> + /* irq */
> + .flags = IORESOURCE_IRQ,
> + }
> +};
> +
> +static struct platform_device spe_dev = {
> + .name = ARMV8_SPE_PDEV_NAME,
> + .id = -1,
> + .resource = spe_resources,
> + .num_resources = ARRAY_SIZE(spe_resources)
> +};
> +
> +/*
> + * For lack of a better place, hook the normal PMU MADT walk
> + * and create a SPE device if we detect a recent MADT with
> + * a homogeneous PPI mapping.
> + */
> +static int arm_spe_acpi_register_device(void)
> +{
> + int cpu, hetid, irq, ret;
> + bool first = true;
> + u16 gsi = 0;
> +
> + /*
> + * sanity check all the GICC tables for the same interrupt number
> + * for now we only support homogeneous ACPI/SPE machines.
> + */
> + for_each_possible_cpu(cpu) {
> + struct acpi_madt_generic_interrupt *gicc;
> +
> + gicc = acpi_cpu_get_madt_gicc(cpu);
> + if (gicc->header.length < ACPI_MADT_GICC_SPE)
> + return -ENODEV;
> +
> + if (first) {
> + gsi = gicc->spe_interrupt;
> + if (!gsi)
> + return -ENODEV;
> + hetid = find_acpi_cpu_topology_hetero_id(cpu);
> + first = false;
> + } else if ((gsi != gicc->spe_interrupt) ||
> + (hetid != find_acpi_cpu_topology_hetero_id(cpu))) {
> + pr_warn("ACPI: SPE must be homogeneous\n");
> + return -EINVAL;
> + }
> + }
> +
> + irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE,
> + ACPI_ACTIVE_HIGH);
> + if (irq < 0) {
> + pr_warn("ACPI: SPE Unable to register interrupt: %d\n", gsi);
> + return irq;
> + }
> +
> + spe_resources[0].start = irq;
> + ret = platform_device_register(&spe_dev);
> + if (ret < 0) {
> + pr_warn("ACPI: SPE: Unable to register device\n");
> + acpi_unregister_gsi(gsi);
> + }
> +
> + return ret;
> +}
> +#else
> +static inline int arm_spe_acpi_register_device(void)
> +{
> + return -ENODEV;
> +}
> +#endif /* CONFIG_ARM_SPE_PMU */
> +
> static int arm_pmu_acpi_parse_irqs(void)
> {
> int irq, cpu, irq_cpu, err;
> @@ -279,6 +352,8 @@ static int arm_pmu_acpi_init(void)
> if (acpi_disabled)
> return 0;
>
> + arm_spe_acpi_register_device(); /* failures are expected */
Sounds ominous and it is false, ACPI never fails :)
Nit: if we don't check the return value what's the point of
returning it.
Nothing problematic, if you manage to update the code before
merging it is a plus.
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieral...@arm.com>
> ret = arm_pmu_acpi_parse_irqs();
> if (ret)
> return ret;
> diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
> index 4641e850b204..784bc58f165a 100644
> --- a/include/linux/perf/arm_pmu.h
> +++ b/include/linux/perf/arm_pmu.h
> @@ -175,4 +175,6 @@ void armpmu_free_irq(int irq, int cpu);
>
> #endif /* CONFIG_ARM_PMU */
>
> +#define ARMV8_SPE_PDEV_NAME "arm,spe-v1"
> +
> #endif /* __ARM_PMU_H__ */
> --
> 2.21.0
>
