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

Marc Zyngier
2014-09-02T16:00:08Z

On 02/09/14 16:45, Hanjun Guo wrote:
> 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).

Then it is worth mentioning that this is an arbitrary limit, unrelated
to what the architecture describes.

Thanks,

M.
--
Jazz is not dead. It just smells funny...
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