Re: [PATCH v3 13/17] ARM64 / ACPI: Add GICv2 specific ACPI boot support

Hanjun Guo
2014-09-02T15:48:37Z

On 2014年09月02日 21:02, Marc Zyngier wrote:
> On 02/09/14 12:48, Tomasz Nowicki wrote:
>> On 01.09.2014 19:35, Marc Zyngier wrote:
>>> On 01/09/14 15:57, Hanjun Guo wrote:
>>>> From: Tomasz Nowicki <tomasz.nowicki@linaro.org>
>>>>
>>>> ACPI kernel uses MADT table for proper GIC initialization. It needs to
>>>> parse GIC related subtables, collect CPU interface and distributor
>>>> addresses and call driver initialization function (which is hardware
>>>> abstraction agnostic). In a similar way, FDT initialize GICv1/2.
>>>>
>>>> NOTE: This commit allow to initialize GICv1/2 only.
>>> I cannot help but notice that there is no support for KVM here. It'd be
>>> good to add a note to that effect, so that people do not expect
>>> virtualization support to be working when booting with ACPI.
>> yes, it is worth mentioning!
>>
>>>> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
>>>> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
>>>> ---
>>>> arch/arm64/include/asm/acpi.h | 2 -
>>>> arch/arm64/kernel/acpi.c | 23 +++++++
>>>> arch/arm64/kernel/irq.c | 5 ++
>>>> drivers/irqchip/irq-gic.c | 114 ++++++++++++++++++++++++++++++++++
>>>> include/linux/irqchip/arm-gic-acpi.h | 33 ++++++++++
>>>> 5 files changed, 175 insertions(+), 2 deletions(-)
>>>> create mode 100644 include/linux/irqchip/arm-gic-acpi.h
>>>>
>>>> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
>>>> index a867467..5d2ab63 100644
>>>> --- a/arch/arm64/include/asm/acpi.h
>>>> +++ b/arch/arm64/include/asm/acpi.h
>>>> @@ -97,8 +97,6 @@ void __init acpi_smp_init_cpus(void);
>>>> extern int (*acpi_suspend_lowlevel)(void);
>>>> #define acpi_wakeup_address 0
>>>>
>>>> -#define ACPI_MAX_GIC_CPU_INTERFACE_ENTRIES 65535
>>>> -
>>>> #else
>>>>
>>>> static inline bool acpi_psci_present(void) { return false; }
>>>> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
>>>> index 354b912..b3b82b0 100644
>>>> --- a/arch/arm64/kernel/acpi.c
>>>> +++ b/arch/arm64/kernel/acpi.c
>>>> @@ -23,6 +23,7 @@
>>>> #include <linux/irqdomain.h>
>>>> #include <linux/bootmem.h>
>>>> #include <linux/smp.h>
>>>> +#include <linux/irqchip/arm-gic-acpi.h>
>>>>
>>>> #include <asm/cputype.h>
>>>> #include <asm/cpu_ops.h>
>>>> @@ -313,6 +314,28 @@ void __init acpi_boot_table_init(void)
>>>> pr_err("Can't find FADT or error happened during parsing FADT\n");
>>>> }
>>>>
>>>> +void __init acpi_gic_init(void)
>>>> +{
>>>> + struct acpi_table_header *table;
>>>> + acpi_status status;
>>>> + acpi_size tbl_size;
>>>> + int err;
>>>> +
>>>> + status = acpi_get_table_with_size(ACPI_SIG_MADT, 0, &table, &tbl_size);
>>>> + if (ACPI_FAILURE(status)) {
>>>> + const char *msg = acpi_format_exception(status);
>>>> +
>>>> + pr_err("Failed to get MADT table, %s\n", msg);
>>>> + return;
>>>> + }
>>>> +
>>>> + err = gic_v2_acpi_init(table);
>>>> + if (err)
>>>> + pr_err("Failed to initialize GIC IRQ controller");
>>> What will happen when you get to implement GICv3 support? Another entry
>>> like this? Why isn't this entirely contained in the GIC driver? Do I
>>> sound like a stuck record?
>> There will be another call to GICv3 init:
>> [...]
>> err = gic_v3_acpi_init(table);
>> if (err)
>> err = gic_v2_acpi_init(table);
>> if (err)
>> pr_err("Failed to initialize GIC IRQ controller");
>> [...]
>> This is the main reason I put common code here.
>>
>>>> +
>>>> + early_acpi_os_unmap_memory((char *)table, tbl_size);
>>>> +}
>>>> +
>>>> /*
>>>> * acpi_suspend_lowlevel() - save kernel state and suspend.
>>>> *
>>>> diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
>>>> index 0f08dfd..c074d60 100644
>>>> --- a/arch/arm64/kernel/irq.c
>>>> +++ b/arch/arm64/kernel/irq.c
>>>> @@ -28,6 +28,7 @@
>>>> #include <linux/irqchip.h>
>>>> #include <linux/seq_file.h>
>>>> #include <linux/ratelimit.h>
>>>> +#include <linux/irqchip/arm-gic-acpi.h>
>>>>
>>>> unsigned long irq_err_count;
>>>>
>>>> @@ -78,6 +79,10 @@ void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
>>>> void __init init_IRQ(void)
>>>> {
>>>> irqchip_init();
>>>> +
>>>> + if (!handle_arch_irq)
>>>> + acpi_gic_init();
>>>> +
>>> Why isn't this called from irqchip_init? It would seem like the logical
>>> spot to probe an interrupt controller.
>> irqchip.c is OF dependent, I want to decouple these from the very
>> beginning.
> No. irqchip.c is not OF dependent, it is just that DT is the only thing
> we support so far. I don't think duplicating the kernel infrastructure
> "because we're different" is the right way.
>
> There is no reason for your probing structure to be artificially
> different (you're parsing the same information, at the same time). Just
> put in place a similar probing mechanism, and this will look a lot better.
>
>>>> if (!handle_arch_irq)
>>>> panic("No interrupt controller found.");
>>>> }
>>>> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
>>>> index 4b959e6..85cbf43 100644
>>>> --- a/drivers/irqchip/irq-gic.c
>>>> +++ b/drivers/irqchip/irq-gic.c
>>>> @@ -33,12 +33,14 @@
>>>> #include <linux/of.h>
>>>> #include <linux/of_address.h>
>>>> #include <linux/of_irq.h>
>>>> +#include <linux/acpi.h>
>>>> #include <linux/irqdomain.h>
>>>> #include <linux/interrupt.h>
>>>> #include <linux/percpu.h>
>>>> #include <linux/slab.h>
>>>> #include <linux/irqchip/chained_irq.h>
>>>> #include <linux/irqchip/arm-gic.h>
>>>> +#include <linux/irqchip/arm-gic-acpi.h>
>>>>
>>>> #include <asm/cputype.h>
>>>> #include <asm/irq.h>
>>>> @@ -1029,3 +1031,115 @@ IRQCHIP_DECLARE(msm_8660_qgic, "qcom,msm-8660-qgic", gic_of_init);
>>>> IRQCHIP_DECLARE(msm_qgic2, "qcom,msm-qgic2", gic_of_init);
>>>>
>>>> #endif
>>>> +
>>>> +#ifdef CONFIG_ACPI
>>>> +static u64 dist_phy_base, cpu_phy_base = ULONG_MAX;
>>> Please use phys_addr_t for physical addresses. The use of ULONG_MAX
>>> looks dodgy. Please have a proper symbol to flag the fact that it hasn't
>>> been assigned yet.
>> Sure, will do.
>>
>>>> +
>>>> +static int __init
>>>> +gic_acpi_parse_madt_cpu(struct acpi_subtable_header *header,
>>>> + const unsigned long end)
>>>> +{
>>>> + struct acpi_madt_generic_interrupt *processor;
>>>> + u64 gic_cpu_base;
>>> phys_addr_t
>>>
>>>> + processor = (struct acpi_madt_generic_interrupt *)header;
>>>> +
>>>> + if (BAD_MADT_ENTRY(processor, end))
>>>> + return -EINVAL;
>>>> +
>>>> + gic_cpu_base = processor->base_address;
>>>> + if (!gic_cpu_base)
>>>> + return -EFAULT;
>>> Is zero an invalid address?
>> Yeah, good point.
>>>> +
>>>> + /*
>>>> + * There is no support for non-banked GICv1/2 register in ACPI spec.
>>>> + * All CPU interface addresses have to be the same.
>>>> + */
>>>> + if (cpu_phy_base != ULONG_MAX && gic_cpu_base != cpu_phy_base)
>>>> + return -EFAULT;
>>>> +
>>>> + cpu_phy_base = gic_cpu_base;
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int __init
>>>> +gic_acpi_parse_madt_distributor(struct acpi_subtable_header *header,
>>>> + const unsigned long end)
>>>> +{
>>>> + struct acpi_madt_generic_distributor *dist;
>>>> +
>>>> + dist = (struct acpi_madt_generic_distributor *)header;
>>>> +
>>>> + if (BAD_MADT_ENTRY(dist, end))
>>>> + return -EINVAL;
>>>> +
>>>> + dist_phy_base = dist->base_address;
>>>> + if (!dist_phy_base)
>>>> + return -EFAULT;
>>> Same question about zero.
>>>
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +int __init
>>>> +gic_v2_acpi_init(struct acpi_table_header *table)
>>>> +{
>>>> + void __iomem *cpu_base, *dist_base;
>>>> + int count;
>>>> +
>>>> + /* Collect CPU base addresses */
>>>> + count = acpi_parse_entries(sizeof(struct acpi_table_madt),
>>>> + gic_acpi_parse_madt_cpu, table,
>>>> + ACPI_MADT_TYPE_GENERIC_INTERRUPT,
>>>> + ACPI_MAX_GIC_CPU_INTERFACE_ENTRIES);
>>>> + if (count < 0) {
>>>> + pr_err("Error during GICC entries parsing\n");
>>>> + return -EFAULT;
>>>> + } else if (!count) {
>>>> + /* No GICC entries provided, use address from MADT header */
>>>> + struct acpi_table_madt *madt = (struct acpi_table_madt *)table;
>>>> +
>>>> + if (!madt->address)
>>>> + return -EFAULT;
>>>> +
>>>> + cpu_phy_base = (u64)madt->address;
>>>> + }
>>>> +
>>>> + /*
>>>> + * Find distributor base address. We expect one distributor entry since
>>>> + * ACPI 5.1 spec neither support multi-GIC instances nor GIC cascade.
>>>> + */
>>>> + count = acpi_parse_entries(sizeof(struct acpi_table_madt),
>>>> + gic_acpi_parse_madt_distributor, table,
>>>> + ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR,
>>>> + ACPI_MAX_GIC_DISTRIBUTOR_ENTRIES);
>>>> + if (count <= 0) {
>>>> + pr_err("Error during GICD entries parsing\n");
>>>> + return -EFAULT;
>>>> + } else if (count > 1) {
>>>> + pr_err("More than one GICD entry detected\n");
>>>> + return -EINVAL;
>>>> + }
>>>> +
>>>> + cpu_base = ioremap(cpu_phy_base, ACPI_GIC_CPU_IF_MEM_SIZE);
>>>> + if (!cpu_base) {
>>>> + pr_err("Unable to map GICC registers\n");
>>>> + return -ENOMEM;
>>>> + }
>>>> +
>>>> + dist_base = ioremap(dist_phy_base, ACPI_GIC_DIST_MEM_SIZE);
>>>> + if (!dist_base) {
>>>> + pr_err("Unable to map GICD registers\n");
>>>> + iounmap(cpu_base);
>>>> + return -ENOMEM;
>>>> + }
>>>> +
>>>> + /*
>>>> + * Initialize zero GIC instance (no multi-GIC support). Also, set GIC
>>>> + * as default IRQ domain to allow for GSI registration and GSI to IRQ
>>>> + * number translation (see acpi_register_gsi() and acpi_gsi_to_irq()).
>>>> + */
>>>> + gic_init_bases(0, -1, dist_base, cpu_base, 0, NULL);
>>>> + irq_set_default_host(gic_data[0].domain);
>>>> + return 0;
>>>> +}
>>>> +#endif
>>>> diff --git a/include/linux/irqchip/arm-gic-acpi.h b/include/linux/irqchip/arm-gic-acpi.h
>>>> new file mode 100644
>>>> index 0000000..ce2ae1a8
>>>> --- /dev/null
>>>> +++ b/include/linux/irqchip/arm-gic-acpi.h
>>>> @@ -0,0 +1,33 @@
>>>> +/*
>>>> + * Copyright (C) 2014, Linaro Ltd.
>>>> + * Author: Tomasz Nowicki <tomasz.nowicki@linaro.org>
>>>> + *
>>>> + * This program is free software; you can redistribute it and/or modify
>>>> + * it under the terms of the GNU General Public License version 2 as
>>>> + * published by the Free Software Foundation.
>>>> + */
>>>> +
>>>> +#ifndef ARM_GIC_ACPI_H_
>>>> +#define ARM_GIC_ACPI_H_
>>>> +
>>>> +#include <linux/acpi.h>
>>> Do we need linux/acpi.h here? You could have a separate forward
>>> declaration of struct acpi_table_header, specially in the light of my
>>> last remark below.
>> Indeed, we can do forward declaration instead of #include
>> <linux/acpi.h>. Thanks!
>>
>>>> +
>>>> +#ifdef CONFIG_ACPI
>>>> +#define ACPI_MAX_GIC_CPU_INTERFACE_ENTRIES 65535
>>> With GICv2? I doubt it.
>> I will create macro for each GIC driver:
>> #define ACPI_MAX_GICV2_CPU_INTERFACE_ENTRIES 8
>> #define ACPI_MAX_GICV3_CPU_INTERFACE_ENTRIES 65535
> Where do you get this value (ACPI_MAX_GICV3_CPU_INTERFACE_ENTRIES) from?

This value is for max processors entries in MADT, and we will use it to scan MADT
for SMP/GIC Init, I just make it big enough for GICv3/4. since ACPI core will stop
scan MADT if the real numbers of processors entries are reached no matter
how big ACPI_MAX_GICV3_CPU_INTERFACE_ENTRIES is, I think we can just
define a number big enough then it will work (x86 and ia64 did the same thing).

Thanks
Hanjun
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