[PATCH 09/20] ARM64 / ACPI: Implement core functions for parsing MADT table
Hanjun Guo
hanjun.guo at linaro.org
Fri Jan 24 10:34:06 EST 2014
Hi Marc,
On 2014年01月24日 01:54, Marc Zyngier wrote:
> Hi Hanjun,
>
> On 17/01/14 12:25, Hanjun Guo wrote:
>> Implement core functions for parsing MADT table to get the information
>> about GIC cpu interface and GIC distributor to prepare for SMP and GIC
>> initialization.
>>
>> Signed-off-by: Hanjun Guo <hanjun.guo at linaro.org>
>> ---
>> arch/arm64/include/asm/acpi.h | 3 +
>> drivers/acpi/plat/arm-core.c | 139 ++++++++++++++++++++++++++++++++++++++++-
>> drivers/acpi/tables.c | 21 +++++++
>> 3 files changed, 162 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
>> index e108d9c..c335c6d 100644
>> --- a/arch/arm64/include/asm/acpi.h
>> +++ b/arch/arm64/include/asm/acpi.h
>> @@ -83,6 +83,9 @@ void arch_fix_phys_package_id(int num, u32 slot);
>> extern int (*acpi_suspend_lowlevel)(void);
>> #define acpi_wakeup_address (0)
>>
>> +#define MAX_GIC_CPU_INTERFACE 256
> I'll bite. Where on Earth is this value coming from?
I just thought 256 is big enough for now :(
Yes, should be a larger number for GICv3.
> If that's for
> GICv2, 8 is the maximum. For GICv3+, that's incredibly low, and should
> be probed probed at runtime anyway.
I would prefer to do that, but this value is used to
probe CPUs in MADT :)
>
>> +#define MAX_GIC_DISTRIBUTOR 1 /* should be the same as MAX_GIC_NR */
> No support for cascaded GICs?
Yes, no cascade GICs in ACPI at now.
>
>> +
>> #else /* !CONFIG_ACPI */
>> #define acpi_disabled 1 /* ACPI sometimes enabled on ARM */
>> #define acpi_noirq 1 /* ACPI sometimes enabled on ARM */
>> diff --git a/drivers/acpi/plat/arm-core.c b/drivers/acpi/plat/arm-core.c
>> index 1835b21..8ba3e6f 100644
>> --- a/drivers/acpi/plat/arm-core.c
>> +++ b/drivers/acpi/plat/arm-core.c
>> @@ -46,6 +46,16 @@ EXPORT_SYMBOL(acpi_disabled);
>> int acpi_pci_disabled; /* skip ACPI PCI scan and IRQ initialization */
>> EXPORT_SYMBOL(acpi_pci_disabled);
>>
>> +/*
>> + * Local interrupt controller address,
>> + * GIC cpu interface base address on ARM/ARM64
>> + */
>> +static u64 acpi_lapic_addr __initdata;
> If that's a GIC address, why not call it as such?
thanks for the suggesting, I will update.
>
>> +#define BAD_MADT_ENTRY(entry, end) ( \
>> + (!entry) || (unsigned long)entry + sizeof(*entry) > end || \
>> + ((struct acpi_subtable_header *)entry)->length < sizeof(*entry))
>> +
>> #define PREFIX "ACPI: "
> Just do:
> #define pr_fmt(fmt) "ACPI: " fmt
>
> and remove all the occurrences of PREFIX.
>
>> /* FIXME: this function should be moved to topology.c when it is ready */
>> @@ -92,6 +102,115 @@ void __init __acpi_unmap_table(char *map, unsigned long size)
>> return;
>> }
>>
>> +static int __init acpi_parse_madt(struct acpi_table_header *table)
>> +{
>> + struct acpi_table_madt *madt = NULL;
> No need to initialize this to NULL, you're doing an assignment at the
> next line...
>
>> +
>> + madt = (struct acpi_table_madt *)table;
>> + if (!madt) {
>> + pr_warn(PREFIX "Unable to map MADT\n");
> There is no mapping here, please fix the message accordingly.
Ok, I will address your comments above in next version.
>
>> + return -ENODEV;
>> + }
>> +
>> + if (madt->address) {
>> + acpi_lapic_addr = (u64) madt->address;
> So you're updating this static variable, for the distributor and each
> CPU interface? /me puzzled...
Good catch. So I have a question: do we really have some SoCs
without banked registers on ARM64? if not , I think we can use
a single static variable is ok.
>
>> + pr_info(PREFIX "Local APIC address 0x%08x\n", madt->address);
> Away with this APIC madness. GICC and GICD are the concepts we're all
> familiar with here, and using the proper terminology would certainly
> help reviewing these patches...
That make sense to me too, will update.
>
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * GIC structures on ARM are somthing like Local APIC structures on x86,
>> + * which means GIC cpu interfaces for GICv2/v3. Every GIC structure in
>> + * MADT table represents a cpu in the system.
> And what do you do when your GICv3 doesn't have a memory-mapped
> interface, but only uses system registers?
>
>> + * GIC distributor structures are somthing like IOAPIC on x86. GIC can
>> + * be initialized with information in this structure.
>> + *
>> + * Please refer to chapter5.2.12.14/15 of ACPI 5.0
> A pointer to that documentation?
Please refer to http://www.acpi.info/
>
>> + */
>> +
>> +static int __init
>> +acpi_parse_gic(struct acpi_subtable_header *header, const unsigned long end)
>> +{
>> + struct acpi_madt_generic_interrupt *processor = NULL;
>> +
>> + processor = (struct acpi_madt_generic_interrupt *)header;
>> +
>> + if (BAD_MADT_ENTRY(processor, end))
>> + return -EINVAL;
>> +
>> + acpi_table_print_madt_entry(header);
>> +
>> + return 0;
>> +}
>> +
>> +static int __init
>> +acpi_parse_gic_distributor(struct acpi_subtable_header *header,
>> + const unsigned long end)
>> +{
>> + struct acpi_madt_generic_distributor *distributor = NULL;
>> +
>> + distributor = (struct acpi_madt_generic_distributor *)header;
>> +
>> + if (BAD_MADT_ENTRY(distributor, end))
>> + return -EINVAL;
>> +
>> + acpi_table_print_madt_entry(header);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * Parse GIC cpu interface related entries in MADT
>> + * returns 0 on success, < 0 on error
>> + */
>> +static int __init acpi_parse_madt_gic_entries(void)
>> +{
>> + int count;
>> +
>> + /*
>> + * do a partial walk of MADT to determine how many CPUs
>> + * we have including disabled CPUs
>> + */
>> + count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
>> + acpi_parse_gic, MAX_GIC_CPU_INTERFACE);
>> +
>> + if (!count) {
>> + pr_err(PREFIX "No GIC entries present\n");
>> + return -ENODEV;
>> + } else if (count < 0) {
>> + pr_err(PREFIX "Error parsing GIC entry\n");
>> + return count;
>> + }
> So you do a lot of parsing to count stuff, and then discard the number
> of counted objects... You might as well check that there is at least one
> valid object and stop there.
>
>> + return 0;
>> +}
>> +
>> +/*
>> + * Parse GIC distributor related entries in MADT
>> + * returns 0 on success, < 0 on error
>> + */
>> +static int __init acpi_parse_madt_gic_distributor_entries(void)
>> +{
>> + int count;
>> +
>> + count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR,
>> + acpi_parse_gic_distributor, MAX_GIC_DISTRIBUTOR);
>> +
>> + if (!count) {
>> + pr_err(PREFIX "No GIC distributor entries present\n");
>> + return -ENODEV;
>> + } else if (count < 0) {
>> + pr_err(PREFIX "Error parsing GIC distributor entry\n");
>> + return count;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
>> {
>> *irq = gsi_to_irq(gsi);
>> @@ -141,11 +260,29 @@ static int __init acpi_parse_fadt(struct acpi_table_header *table)
>>
>> static void __init early_acpi_process_madt(void)
>> {
>> - return;
>> + acpi_table_parse(ACPI_SIG_MADT, acpi_parse_madt);
>> }
>>
>> static void __init acpi_process_madt(void)
>> {
>> + int error;
>> +
>> + if (!acpi_table_parse(ACPI_SIG_MADT, acpi_parse_madt)) {
> How many times are you going to parse the same table? Surely you can
> stash whatever information you need and be done with it?
good catch, we already addressed this problem, and will
update in next version.
>
>> + /*
>> + * Parse MADT GIC cpu interface entries
>> + */
>> + error = acpi_parse_madt_gic_entries();
>> + if (!error) {
>> + /*
>> + * Parse MADT GIC distributor entries
>> + */
>> + acpi_parse_madt_gic_distributor_entries();
>> + }
>> + }
>> +
>> + pr_info("Using ACPI for processor (GIC) configuration information\n");
>> +
>> return;
>> }
>>
>> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
>> index d67a1fe..b3e4615 100644
>> --- a/drivers/acpi/tables.c
>> +++ b/drivers/acpi/tables.c
>> @@ -191,6 +191,27 @@ void acpi_table_print_madt_entry(struct acpi_subtable_header *header)
>> }
>> break;
>>
>> + case ACPI_MADT_TYPE_GENERIC_INTERRUPT:
>> + {
>> + struct acpi_madt_generic_interrupt *p =
>> + (struct acpi_madt_generic_interrupt *)header;
>> + printk(KERN_INFO PREFIX
> Use pr_info
this function use printk always, should change all of them?
>
>> + "GIC (acpi_id[0x%04x] gic_id[0x%04x] %s)\n",
>> + p->uid, p->gic_id,
>> + (p->flags & ACPI_MADT_ENABLED) ? "enabled" : "disabled");
>> + }
>> + break;
>> +
>> + case ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR:
>> + {
>> + struct acpi_madt_generic_distributor *p =
>> + (struct acpi_madt_generic_distributor *)header;
>> + printk(KERN_INFO PREFIX
>> + "GIC Distributor (id[0x%04x] address[0x%08llx] gsi_base[%d])\n",
>> + p->gic_id, p->base_address, p->global_irq_base);
>> + }
>> + break;
>> +
>> default:
>> printk(KERN_WARNING PREFIX
>> "Found unsupported MADT entry (type = 0x%x)\n",
>>
> Most of that code seems to be repeatedly parsing and printing stuff, and
> I fail to see what it actually does.
yes, just print some information when booting.
Thank you very much for the comments.
Hanjun
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