Messages in this thread | | | Date | Tue, 19 Aug 2014 10:47:00 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCH v2 02/18] ARM64 / ACPI: Get RSDP and ACPI boot-time tables |
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On 19/08/14 10:35, Hanjun Guo wrote: > On 2014-8-19 2:30, Sudeep Holla wrote: >> On 04/08/14 16:28, Hanjun Guo wrote: >>> From: Al Stone <al.stone@linaro.org> >>> >>> As we want to get ACPI tables to parse and then use the information >>> for system initialization, we should get the RSDP (Root System >>> Description Pointer) first, it then locates Extended Root Description >>> Table (XSDT) which contains all the 64-bit physical address that >>> pointer to other boot-time tables. >>> >>> Introduce acpi.c and its related head file in this patch to provide >>> fundamental needs of extern variables and functions for ACPI core, >>> and then get boot-time tables as needed. >>> - asm/cpu.h need for ACPI core and will be updated in the future to >>> add definitions for arch_(un)register_cpu which are required for >>> ACPI based physical CPU hotplug; >>
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>>> +/* >>> + * acpi_boot_table_init() called from setup_arch(), always. >>> + * 1. find RSDP and get its address, and then find XSDT >>> + * 2. extract all tables and checksums them all >>> + * >>> + * We can parse ACPI boot-time tables such as FADT, MADT after >>> + * this function is called. >>> + */ >>> +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()) { >> >> Can't we call acpi_table_init directly in setup ? >> IIUC x86 has acpi_boot_table_init as it parses Boot Flags >> table(ACPI_SIG_BOOT) > > Yes, we can. But I think it not a big deal to dot that, if that > makes the code more readable, I will update it. >
I agree, but I actually wanted to check if we ever have to use/parse Simple Boot Flag Table on ARM64 which is reserved but not part of ACPI spec. I assume x86 use either for Legacy reason or firmware expects it.
Regards, Sudeep
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