[PATCH v2 02/18] ARM64 / ACPI: Get RSDP and ACPI boot-time tables

[sudeep.holla@arm.com (Sudeep Holla)]

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;

This can go away now, as it's already present in v3.17-rc1

>    - asm/acenv.h for arch specific ACPICA environments and
>      implementation;
>    - asm/acpi.h for arch specific variables and functions needed by
>      ACPI driver core;
>    - acpi.c for ARM64 related ACPI implementation for ACPI driver
>      core;
>
> acpi_boot_table_init() is introduced to get RSDP and boot-time tables,
> it will be called in setup_arch() before paging_init(), so we should
> use eary_memremap() mechanism here to get the RSDP and all the table
> pointers.
>
> Signed-off-by: Al Stone <al.stone@linaro.org>
> Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
> ---
>   arch/arm64/include/asm/acenv.h |   18 +++++++++++
>   arch/arm64/include/asm/acpi.h  |   45 ++++++++++++++++++++++++++
>   arch/arm64/include/asm/cpu.h   |   11 +++++++
>   arch/arm64/kernel/Makefile     |    1 +
>   arch/arm64/kernel/acpi.c       |   69 ++++++++++++++++++++++++++++++++++++++++
>   arch/arm64/kernel/setup.c      |    4 +++
>   6 files changed, 148 insertions(+)
>   create mode 100644 arch/arm64/include/asm/acenv.h
>   create mode 100644 arch/arm64/include/asm/acpi.h
>   create mode 100644 arch/arm64/include/asm/cpu.h
>   create mode 100644 arch/arm64/kernel/acpi.c
>

[...]

> +
> +/*
> + * Checking for the posibility that the CPU can be initialized from the MADT.
> + * It's used from ACPI core in crash kernel case where boot CPU is not
> + * necessarily CPU0 like spec demands. Since MADT must provide at least one

Do you mean ACPI spec demands CPU0 to be boot cpu ?

IIUC it's basically to handle UP system with SMP kernel. IWO if all the
ACPI resources are reused from SMP system to boot UP system with SMP
kernel, with this check the ACPI core won't override the CPU index
obtained from GIC/APIC mapping to zero.

> + * GICC structure for GIC initialization, CPU will be always available in
> + * MADT on ARM64.
> + */
> +static inline bool acpi_has_cpu_in_madt(void)
> +{
> +	return 1;

probably true instead of 1

> +}
> +
> +static inline void arch_fix_phys_package_id(int num, u32 slot) { }
> +
> +#endif /* CONFIG_ACPI */
> +
> +#endif /*_ASM_ACPI_H*/
> diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h
> new file mode 100644
> index 0000000..cee7d3f
> --- /dev/null
> +++ b/arch/arm64/include/asm/cpu.h
> @@ -0,0 +1,11 @@
> +/*
> + *  Copyright (C) 2013-2014 ARM Ltd.
> + *
> + * 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 __ASM_CPU_H
> +#define __ASM_CPU_H
> +
> +#endif
> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> index cdaedad..b568c26 100644
> --- a/arch/arm64/kernel/Makefile
> +++ b/arch/arm64/kernel/Makefile
> @@ -29,6 +29,7 @@ arm64-obj-$(CONFIG_ARM64_CPU_SUSPEND)	+= sleep.o suspend.o
>   arm64-obj-$(CONFIG_JUMP_LABEL)		+= jump_label.o
>   arm64-obj-$(CONFIG_KGDB)		+= kgdb.o
>   arm64-obj-$(CONFIG_EFI)			+= efi.o efi-stub.o efi-entry.o
> +arm64-obj-$(CONFIG_ACPI)		+= acpi.o
>
>   obj-y					+= $(arm64-obj-y) vdso/
>   obj-m					+= $(arm64-obj-m)
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> new file mode 100644
> index 0000000..395778c
> --- /dev/null
> +++ b/arch/arm64/kernel/acpi.c
> @@ -0,0 +1,69 @@
> +/*
> + *  ARM64 Specific Low-Level ACPI Boot Support
> + *
> + *  Copyright (C) 2013-2014, Linaro Ltd.
> + *	Author: Al Stone <al.stone@linaro.org>
> + *	Author: Graeme Gregory <graeme.gregory@linaro.org>
> + *	Author: Hanjun Guo <hanjun.guo@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.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/acpi.h>
> +#include <linux/cpumask.h>
> +#include <linux/memblock.h>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/bootmem.h>
> +#include <linux/smp.h>
> +
> +int acpi_noirq;			/* skip ACPI IRQ initialization */
> +int acpi_disabled;
> +EXPORT_SYMBOL(acpi_disabled);
> +
> +int acpi_pci_disabled;		/* skip ACPI PCI scan and IRQ initialization */
> +EXPORT_SYMBOL(acpi_pci_disabled);
> +
> +/*
> + * __acpi_map_table() will be called before page_init(), so early_ioremap()
> + * or early_memremap() should be called here to for ACPI table mapping.
> + */
> +char *__init __acpi_map_table(unsigned long phys, unsigned long size)
> +{
> +	if (!phys || !size)
> +		return NULL;
> +
> +	return early_memremap(phys, size);
> +}
> +
> +void __init __acpi_unmap_table(char *map, unsigned long size)
> +{
> +	if (!map || !size)
> +		return;
> +
> +	early_memunmap(map, size);
> +}
> +
> +/*
> + * 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)

> +		disable_acpi();
> +		return;
> +	}
> +}
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index fc50461..85c6326 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -43,6 +43,7 @@
>   #include <linux/of_fdt.h>
>   #include <linux/of_platform.h>
>   #include <linux/efi.h>
> +#include <linux/acpi.h>
>
>   #include <asm/fixmap.h>
>   #include <asm/cputype.h>
> @@ -385,6 +386,9 @@ void __init setup_arch(char **cmdline_p)
>   	efi_init();
>   	arm64_memblock_init();
>
> +	/* Parse the ACPI tables for possible boot-time configuration */
> +	acpi_boot_table_init();
> +
>   	paging_init();
>   	request_standard_resources();
>
>