Messages in this thread | | | Date | Wed, 2 Aug 2023 08:14:36 +0530 | Subject | Re: [PATCH V2 1/4] arm_pmu: acpi: Refactor arm_spe_acpi_register_device() | From | Anshuman Khandual <> |
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On 8/1/23 20:19, Will Deacon wrote: > On Tue, Aug 01, 2023 at 03:10:49PM +0530, Anshuman Khandual wrote: >> Sanity checking all the GICC tables for same interrupt number, and ensuring >> a homogeneous ACPI based machine, could be used for other platform devices >> as well. Hence this refactors arm_spe_acpi_register_device() into a common >> helper arm_acpi_register_pmu_device(). >> >> 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 >> Co-developed-by: Will Deacon <will@kernel.org> >> Signed-off-by: Will Deacon <will@kernel.org> >> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> >> --- >> drivers/perf/arm_pmu_acpi.c | 110 +++++++++++++++++++++++------------- >> 1 file changed, 70 insertions(+), 40 deletions(-) >> >> diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c >> index 90815ad762eb..d9d5a7bbb92f 100644 >> --- a/drivers/perf/arm_pmu_acpi.c >> +++ b/drivers/perf/arm_pmu_acpi.c >> @@ -70,6 +70,68 @@ static void arm_pmu_acpi_unregister_irq(int cpu) >> } >> >> #if IS_ENABLED(CONFIG_ARM_SPE_PMU) >> +static int >> +arm_acpi_register_pmu_device(struct platform_device *pdev, u8 len, >> + u16 (*parse_gsi)(struct acpi_madt_generic_interrupt *)) >> +{ >> + int cpu, hetid, irq, ret; >> + bool matched = false; >> + u16 gsi = 0; >> + >> + /* >> + * Ensure that platform device must have IORESOURCE_IRQ >> + * resource to hold gsi interrupt. >> + */ >> + if (pdev->num_resources != 1) >> + return -ENXIO; >> + >> + if (pdev->resource[0].flags != IORESOURCE_IRQ) >> + return -ENXIO; >> + >> + /* >> + * Sanity check all the GICC tables for the same interrupt >> + * number. For now, only support homogeneous ACPI machines. >> + */ >> + for_each_possible_cpu(cpu) { >> + struct acpi_madt_generic_interrupt *gicc; >> + u16 this_gsi; >> + >> + gicc = acpi_cpu_get_madt_gicc(cpu); >> + if (gicc->header.length < len) >> + return matched ? -ENXIO : 0; >> + >> + this_gsi = parse_gsi(gicc); >> + if (!this_gsi) >> + return matched ? -ENXIO : 0; > > I think you can push this check into the conditional below... > >> + >> + if (!matched) { >> + hetid = find_acpi_cpu_topology_hetero_id(cpu); > > ... i.e. add a: > > if (!this_gsi) > return -ENXIO; > > here. > >> + gsi = this_gsi; >> + matched = true; > > And then, come to think of it, can we get rid of 'matched' altogether? > Since a gsi of 0 is treated as invalid, we could just check that instead, > no? So this becomes: > > > gicc = acpi_cpu_get_madt_gicc(cpu); > if (gicc->header.length < len) > return gsi ? -ENXIO : 0; > > this_hetid = find_acpi_cpu_topology_hetero_id(cpu); > this_gsi = parse_gsi(gicc); > if (!gsi) { > if (!this_gsi) > return -ENXIO;
Unlike before, this returns -ENXIO on the very first instance itself without a match. Previously this returned 0 in such cases. But I guess that is okay.
> gsi = this_gsi; > hetid = this_hetid; > } else if (hetid != this_hetid || gsi != this_gsi) { > pr_warn("ACPI: %s: must be homogeneous\n", pdev->name); > return -ENXIO; > } > > > What do you reckon?
This makes sense, and the modified function will look something like
arm_acpi_register_pmu_device(struct platform_device *pdev, u8 len, u16 (*parse_gsi)(struct acpi_madt_generic_interrupt *)) { int cpu, irq, ret; u16 gsi = 0;
/* * Ensure that platform device must have IORESOURCE_IRQ * resource to hold gsi interrupt. */ if (pdev->num_resources != 1) return -ENXIO;
if (pdev->resource[0].flags != IORESOURCE_IRQ) return -ENXIO;
/* * Sanity check all the GICC tables for the same interrupt * number. For now, only support homogeneous ACPI machines. */ for_each_possible_cpu(cpu) { struct acpi_madt_generic_interrupt *gicc; int this_hetid, hetid; u16 this_gsi;
gicc = acpi_cpu_get_madt_gicc(cpu); if (gicc->header.length < len) return gsi ? -ENXIO : 0;
this_hetid = find_acpi_cpu_topology_hetero_id(cpu); this_gsi = parse_gsi(gicc); if (!gsi) { if (!this_gsi) return -ENXIO;
hetid = this_hetid; gsi = this_gsi; } else if (hetid != this_hetid || gsi != this_gsi) { pr_warn("ACPI: %s: must be homogeneous\n", pdev->name); return -ENXIO; } }
irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH); if (irq < 0) { pr_warn("ACPI: %s Unable to register interrupt: %d\n", pdev->name, gsi); return -ENXIO; }
pdev->resource[0].start = irq; ret = platform_device_register(pdev); if (ret < 0) { pr_warn("ACPI: %s: Unable to register device\n", pdev->name); acpi_unregister_gsi(gsi); } return ret; }
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