Date:	Wed, 25 Mar 2015 16:44:53 +0000
From:	Catalin Marinas <catalin.marinas@....com>
To:	Hanjun Guo <hanjun.guo@...aro.org>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Will Deacon <will.deacon@....com>,
	Olof Johansson <olof@...om.net>,
	Grant Likely <grant.likely@...aro.org>,
	Mark Rutland <mark.rutland@....com>,
	Ashwin Chaugule <ashwinc@...eaurora.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
	Robert Richter <rric@...nel.org>,
	Arnd Bergmann <arnd@...db.de>,
	Graeme Gregory <graeme.gregory@...aro.org>,
	linaro-acpi@...ts.linaro.org, Marc Zyngier <marc.zyngier@....com>,
	Jon Masters <jcm@...hat.com>,
	Timur Tabi <timur@...eaurora.org>,
	Mark Salter <msalter@...hat.com>, linux-kernel@...r.kernel.org,
	Tomasz Nowicki <tomasz.nowicki@...aro.org>,
	Al Stone <al.stone@...aro.org>, linux-acpi@...r.kernel.org,
	Mark Brown <broonie@...nel.org>,
	Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
	Sudeep Holla <Sudeep.Holla@....com>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [patch v11 04/23] ARM64 / ACPI: Get RSDP and ACPI boot-time
 tables

On Tue, Mar 24, 2015 at 10:02:37PM +0800, Hanjun Guo wrote:
> From: Al Stone <al.stone@...aro.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/acenv.h for arch specific ACPICA environments and
>     implementation, It is needed unconditionally by ACPI core;
>   - 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.
> 
> FADT Major.Minor version was introduced in ACPI 5.1, it is the same
> as ACPI version.
> 
> In ACPI 5.1, some major gaps are fixed for ARM, such as updates in
> MADT table for GIC and SMP init, without those updates, we can not
> get the MPIDR for SMP init, and GICv2/3 related init information, so
> we can't boot arm64 ACPI properly with table versions predating 5.1.
> 
> If firmware provides ACPI tables with ACPI version less than 5.1,
> OS has no way to retrieve the configuration data that is necessary
> to init SMP boot protocol and the GIC properly, so disable ACPI if
> we get an FADT table with version less that 5.1 when acpi_boot_table_init()
> called.
> 
> CC: Catalin Marinas <catalin.marinas@....com>
> CC: Will Deacon <will.deacon@....com>
> CC: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
> Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
> Tested-by: Yijing Wang <wangyijing@...wei.com>
> Tested-by: Mark Langsdorf <mlangsdo@...hat.com>
> Tested-by: Jon Masters <jcm@...hat.com>
> Tested-by: Timur Tabi <timur@...eaurora.org>
> Tested-by: Robert Richter <rrichter@...ium.com>
> Acked-by: Robert Richter <rrichter@...ium.com>
> Acked-by: Olof Johansson <olof@...om.net>
> Acked-by: Grant Likely <grant.likely@...aro.org>
> Signed-off-by: Al Stone <al.stone@...aro.org>
> Signed-off-by: Graeme Gregory <graeme.gregory@...aro.org>
> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@...aro.org>
> Signed-off-by: Hanjun Guo <hanjun.guo@...aro.org>

Acked-by: Catalin Marinas <catalin.marinas@....com>

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