From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ashwin Chaugule Subject: Re: [PATCH v3 6/6] ACPI: import watchdog info of GTDT into platform device Date: Tue, 26 May 2015 11:35:04 -0400 Message-ID: References: <=fu.wei@linaro.org> <1432548193-19569-1-git-send-email-fu.wei@linaro.org> <1432548193-19569-7-git-send-email-fu.wei@linaro.org> <20150526122858.GJ1565@arm.com> <20150526151842.GP1565@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150526151842.GP1565@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Will Deacon Cc: "fu.wei@linaro.org" , "suravee.suthikulpanit@amd.com" , "linaro-acpi@lists.linaro.org" , "linux-watchdog@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-doc@vger.kernel.org" , "tekkamanninja@gmail.com" , "graeme.gregory@linaro.org" , "al.stone@linaro.org" , "hanjun.guo@linaro.org" , "timur@codeaurora.org" , "arnd@arndb.de" , "linux@roeck-us.net" , "vgandhi@codeaurora.org" , "wim@iguana.be" , "jcm@redhat.com" , leo.duran@amd.com List-Id: devicetree@vger.kernel.org On 26 May 2015 at 11:18, Will Deacon wrote: > On Tue, May 26, 2015 at 04:02:56PM +0100, Ashwin Chaugule wrote: >> On 26 May 2015 at 08:28, Will Deacon wrote: >> > On Mon, May 25, 2015 at 11:03:13AM +0100, fu.wei@linaro.org wrote: >> >> From: Fu Wei >> >> >> >> Parse SBSA Generic Watchdog Structure in GTDT table of ACPI, >> >> and create a platform device with that information. >> >> This platform device can be used by the ARM SBSA Generic >> >> Watchdog driver. >> >> >> >> Tested-by: Suravee Suthikulpanit >> >> Tested-by: Timur Tabi >> >> Signed-off-by: Fu Wei >> >> --- >> >> arch/arm64/kernel/acpi.c | 145 +++++++++++++++++++++++++++++++++= ++++++++++++++ >> >> 1 file changed, 145 insertions(+) >> > >> > Why does this all need to be under arch/arm64? The GTDT really isn= 't >> > architecture-specific, so I'd *much* rather it was parsed in the d= river code >> > itself, like we already do for the architected timer. The GIC is a= n >> > exception because it's in the MADT, which we need to parse in the = arch code >> > to configure SMP properly. >> >> I'm not really against refactoring the code. But the GTDT looks quit= e >> specific to ARM.. >> >> ---8<---- >> 5.2.24 Generic Timer Description Table (GTDT) >> This section describes the format of the Generic Timer Description >> Table (GTDT), which provides >> OSPM with information about a system=E2=80=99s Generic Timers config= uration. >> The Generic Timer (GT) is >> a standard timer interface implemented on ARM processor-based system= s. >> The GT hardware >> specification can be found at Links to ACPI-Related Documents >> (http://uefi.org/acpi) under the >> heading ARM Architecture. The GTDT provides OSPM with information >> about a system's GT >> interrupt configurations, for both per-processor timers, and platfor= m >> (memory-mapped) timers. >> The GT specification defines the following per-processor timers: >> =E2=80=A2 Secure privilege level 1 (EL1) timer, >> =E2=80=A2 Non-Secure EL1 timer, >> =E2=80=A2 Non-Secure privilege level 2 (EL2) timer, >> =E2=80=A2 Virtual timer, >> and the following Platform (memory-mapped) timers. >> =E2=80=A2 GT Block >> =E2=80=A2 Server Base System Architecture (SBSA) Generic Watchdog >> ---8<---- > > Sure, the device it describes may only ever exist on ARM systems, but= by > that logic then we should be moving lots of drivers back under arch/a= rm[64]. Sure. Not arguing about that. :) You said the GTDT isn't really arch specific. That was a bit confusing. > > The ARM architecture says precisely *nothing* about ACPI, so we shoul= d > try to keep arch/arm64/kernel/acpi.c to a minimum and not shovel all = sorts > of table conversion code in there for random peripherals. > > Will