Message-ID: <54D33C75.8030405@linaro.org>
Date: Thu, 05 Feb 2015 17:48:37 +0800
From: Hanjun Guo <hanjun.guo@linaro.org>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0
MIME-Version: 1.0
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC: Catalin Marinas <Catalin.Marinas@arm.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Olof Johansson <olof@lixom.net>, Arnd Bergmann <arnd@arndb.de>,
        Mark Rutland <Mark.Rutland@arm.com>,
        "grant.likely@linaro.org" <grant.likely@linaro.org>,
        Will Deacon <Will.Deacon@arm.com>,
        "graeme.gregory@linaro.org" <graeme.gregory@linaro.org>,
        Sudeep Holla <Sudeep.Holla@arm.com>, "jcm@redhat.com" <jcm@redhat.com>,
        Jason Cooper <jason@lakedaemon.net>,
        Marc Zyngier <Marc.Zyngier@arm.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Mark Brown <broonie@kernel.org>, Rob Herring <robh@kernel.org>,
        Robert Richter <rric@kernel.org>, Randy Dunlap <rdunlap@infradead.org>,
        Charles Garcia-Tobin <Charles.Garcia-Tobin@arm.com>,
        "phoenix.liyi@huawei.com" <phoenix.liyi@huawei.com>,
        Timur Tabi <timur@codeaurora.org>,
        Ashwin Chaugule <ashwinc@codeaurora.org>,
        "suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>,
        Mark Langsdorf <mlangsdo@redhat.com>,
        "wangyijing@huawei.com" <wangyijing@huawei.com>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linaro-acpi@lists.linaro.org" <linaro-acpi@lists.linaro.org>,
        Tomasz Nowicki <tomasz.nowicki@linaro.org>
Subject: Re: [PATCH v8 11/21] ARM64 / ACPI: Get PSCI flags in FADT for PSCI
 init
References: <1422881149-8177-1-git-send-email-hanjun.guo@linaro.org> <1422881149-8177-12-git-send-email-hanjun.guo@linaro.org> <20150204164328.GF22035@red-moon>
In-Reply-To: <20150204164328.GF22035@red-moon>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1401
Lines: 35

On 2015年02月05日 00:43, Lorenzo Pieralisi wrote:
> On Mon, Feb 02, 2015 at 12:45:39PM +0000, Hanjun Guo wrote:
>> From: Graeme Gregory <graeme.gregory@linaro.org>
>>
>> There are two flags: PSCI_COMPLIANT and PSCI_USE_HVC. When set,
>> the former signals to the OS that the firmware is PSCI compliant.
>> The latter selects the appropriate conduit for PSCI calls by
>> toggling between Hypervisor Calls (HVC) and Secure Monitor Calls
>> (SMC).
>>
>> FADT table contains such information in ACPI 5.1, FADT table was
>> parsed in ACPI table init and copy to struct acpi_gbl_FADT, so
>> use the flags in struct acpi_gbl_FADT for PSCI init.
>
> So you do rely on a global FADT being available, if you use it for PSCI
> detection you can use it for ACPI revision detection too, right ?

Yes, I think so.

>
> Point is, either we should not use the global FADT table, or we use
> it consistently, or there is something I am unaware of that prevents
> you from using in some code paths and I would like to understand
> why.

global FADT table is initialized when parsing the tables from RSDP in
ACPICA core, and it should be work on ARM64 too.

Thanks
Hanjun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/