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SubjectRe: [Linaro-acpi] [PATCH 04/20] ARM64 / ACPI: Introduce arm_core.c and its related head file
Hi Lorenzo,

W dniu 22.01.2014 12:54, Lorenzo Pieralisi pisze:
> On Fri, Jan 17, 2014 at 12:24:58PM +0000, Hanjun Guo wrote:
>
> [...]
>
>> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
>> index bd9bbd0..2210353 100644
>> --- a/arch/arm64/kernel/setup.c
>> +++ b/arch/arm64/kernel/setup.c
>> @@ -41,6 +41,7 @@
>> #include <linux/memblock.h>
>> #include <linux/of_fdt.h>
>> #include <linux/of_platform.h>
>> +#include <linux/acpi.h>
>>
>> #include <asm/cputype.h>
>> #include <asm/elf.h>
>> @@ -225,6 +226,11 @@ void __init setup_arch(char **cmdline_p)
>>
>> arm64_memblock_init();
>>
>> + /* Parse the ACPI tables for possible boot-time configuration */
>> + acpi_boot_table_init();
>> + early_acpi_boot_init();
>> + acpi_boot_init();
>> +
>> paging_init();
>
> Can I ask you please why we need to parse ACPI tables before
> paging_init() ?
This is for future usage and because of couple of reasons. Mainly SRAT
table parsing should be done (before paging_init()) for proper NUMA
initialization and then paging_init().

Regards,
Tomasz
>
> [...]
>
>> +/*
>> + * __acpi_map_table() will be called before page_init(), so early_ioremap()
>> + * or early_memremap() should be called here.
>
> Again, why is this needed ? What's needed before paging_init() from ACPI ?
>
> [...]
>
>> +/*
>> + * acpi_boot_table_init() and acpi_boot_init()
>> + * called from setup_arch(), always.
>> + * 1. checksums all tables
>> + * 2. enumerates lapics
>> + * 3. enumerates io-apics
>> + *
>> + * acpi_table_init() is separated to allow reading SRAT without
>> + * other side effects.
>> + */
>> +void __init acpi_boot_table_init(void)
>> +{
>> + /*
>> + * If acpi_disabled, bail out
>> + */
>> + if (acpi_disabled)
>> + return;
>> +
>> + /*
>> + * Initialize the ACPI boot-time table parser.
>> + */
>> + if (acpi_table_init()) {
>> + disable_acpi();
>> + return;
>> + }
>> +}
>> +
>> +int __init early_acpi_boot_init(void)
>> +{
>> + /*
>> + * If acpi_disabled, bail out
>> + */
>> + if (acpi_disabled)
>> + return -ENODEV;
>> +
>> + /*
>> + * Process the Multiple APIC Description Table (MADT), if present
>> + */
>> + early_acpi_process_madt();
>> +
>> + return 0;
>> +}
>> +
>> +int __init acpi_boot_init(void)
>> +{
>> + /*
>> + * If acpi_disabled, bail out
>> + */
>> + if (acpi_disabled)
>> + return -ENODEV;
>> +
>> + acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt);
>> +
>> + /*
>> + * Process the Multiple APIC Description Table (MADT), if present
>> + */
>> + acpi_process_madt();
>> +
>> + return 0;
>> +}
>
> Well, apart from having three init calls, one returning void and two
> returning proper values, do not understand why, and do not understand
> why we need three calls in the first place...why should we process MADT
> twice in two separate calls ? What is supposed to change in between that
> prevents you from merging the two together ?
>
> Thanks,
> Lorenzo
>
>
> _______________________________________________
> Linaro-acpi mailing list
> Linaro-acpi@lists.linaro.org
> http://lists.linaro.org/mailman/listinfo/linaro-acpi
>


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