From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aneesh V Date: Fri, 19 Aug 2011 19:46:44 +0530 Subject: [U-Boot] [PATCH 3/3 v2] ARM: ARM926EJS - Add cache operations In-Reply-To: <201108191455.52899.marek.vasut@gmail.com> References: <1313745795-1326-1-git-send-email-hong.xu@atmel.com> <201108191146.22942.marek.vasut@gmail.com> <4E4E3E52.1050900@ti.com> <201108191455.52899.marek.vasut@gmail.com> Message-ID: <4E4E704C.8030103@ti.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Friday 19 August 2011 06:25 PM, Marek Vasut wrote: > On Friday, August 19, 2011 12:43:30 PM Aneesh V wrote: >> Hi Marek, >> >> On Friday 19 August 2011 03:16 PM, Marek Vasut wrote: >>> On Friday, August 19, 2011 11:37:29 AM Aneesh V wrote: >>>> Hi Hong, >>>> >>>> On Friday 19 August 2011 02:53 PM, Hong Xu wrote: >>>>> Add a new file arch/arm/cpu/arm926ejs/cache.c and put cache operations >>>>> into this file. >>>> >>>> How about converting as much as possible of these to armv5/armv6 generic >>>> code as I mentioned in this thread: >>>> >>>> http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/105385/focus=1055 >>>> 26 >>>> >>>> On a quick look everything below except the "flush_dcache_all()" seems >>>> to be armv5 generic. >>> >>> I'd be _VERY_ careful here. And this "seems" doesn't sound very >>> convincing. Are you dead sure it won't break any v5 CPU we support? >> >> What Hong has used is operations mentioned in the ARMv5 architecture >> and these are not marked as IMPLEMENTATION DEFINED. So, compliant >> implementations should implement those CP15 operations. They may >> enhance the operations by adding their own like ARM926EJS seems to be >> doing with 'flush d-cache all'. >> >> However, I think that's immaterial. Hong can provide this as a library >> and define a CONFIG_* flag to enable it. Let the platform maintainers >> decide whether to use it or not. IMHO, it will definitely be an >> improvement over what we have today. > > Hi, > > It certainly will, but I'm quite relucant to that as it'll also -- since > CONFIG_SYS_DCACHE_OFF and CONFIG_SYS_ICACHE_OFF isn't defined by default -- break > some things. Even though what I said is not exactly an argument for what you > said. > > If you're firm all ARMv5 implement it this way, I'm all for it being done the way > you suggest it! I can not vouch for all the CPUs. But I checked one more - ARM946ES. This one is also implementing all the standard operations that Hong has used('flush d-cache all' used by Hong is not a standard armv5 operation - that seems to be a 926ejs specific one). best regards, Aneesh