From mboxrd@z Thu Jan 1 00:00:00 1970 From: hanjun.guo@linaro.org (Hanjun Guo) Date: Fri, 24 Jan 2014 17:19:41 +0800 Subject: [PATCH 18/20] clocksource / acpi: Add macro CLOCKSOURCE_ACPI_DECLARE In-Reply-To: <3140612.0s75qS6VKb@wuerfel> References: <1389961514-13562-1-git-send-email-hanjun.guo@linaro.org> <52DCE790.6080809@linaro.org> <20140122114616.GB15591@e106331-lin.cambridge.arm.com> <3140612.0s75qS6VKb@wuerfel> Message-ID: <52E2302D.5040001@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2014?01?22? 22:56, Arnd Bergmann wrote: > On Wednesday 22 January 2014 11:46:16 Mark Rutland wrote: >> On Mon, Jan 20, 2014 at 09:08:32AM +0000, Hanjun Guo wrote: >>> On 2014-1-17 22:21, Arnd Bergmann wrote: >>>> On Friday 17 January 2014, Hanjun Guo wrote: >>>>> From: Amit Daniel Kachhap >>>>> >>>>> This macro does the same job as CLOCKSOURCE_OF_DECLARE. The device >>>>> name from the ACPI timer table is matched with all the registered >>>>> timer controllers and matching initialisation routine is invoked. >>>> I wouldn't anticipate this infrastructure to be required. Shouldn't all >>>> ARMv8 machines have an architected timer? >>> I not sure of this, could anyone can give some guidance? if only arch >>> timer is available for ARM64, this will make thing very simple. >> All ARMv8 systems should have an architected timer. >> >> However, they may also have other timers (e.g. global timers for use >> when CPUs are in low power states and their local architected timers >> aren't active). > But all other timers could be regular platform drivers I suppose. No > need for special infrastructure for those. One more information, acpi_early_init() is run before timekeeping_init() now, and that patch was merged into 3.14-rc1. So we can initialize timers for scanning the DSDT table, and it also means that timer defined in DSDT can be initialized early enough. Thanks Hanjun