From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Wu Date: Tue, 9 Jun 2015 11:54:14 +0800 Subject: [U-Boot] [PATCH v2 1/3] ARM: cache: add an empty stub function for invalidate/flush dcache In-Reply-To: <20150608132035.GQ1728@bill-the-cat> References: <1433490452-26402-1-git-send-email-josh.wu@atmel.com> <201506051518.49587.marex@denx.de> <5574F850.7090901@atmel.com> <201506081026.29339.marex@denx.de> <20150608132035.GQ1728@bill-the-cat> Message-ID: <55766366.5090301@atmel.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi, Tom On 6/8/2015 9:20 PM, Tom Rini wrote: > On Mon, Jun 08, 2015 at 10:26:29AM +0200, Marek Vasut wrote: >> On Monday, June 08, 2015 at 04:05:04 AM, Josh Wu wrote: >>> Hi, Marek >>> >>> On 6/5/2015 9:18 PM, Marek Vasut wrote: >>>> On Friday, June 05, 2015 at 09:47:30 AM, Josh Wu wrote: >>>>> Since some driver like ohci, lcd used dcache functions. But some ARM >>>>> cpu don't implement the invalidate_dcache_range()/flush_dcache_range() >>>>> functions. >>>>> >>>>> To avoid compiling errors this patch adds an weak empty stub function >>>>> for all ARM cpu. >>>>> >>>>> And each cpu can implement its own implementation. If not implemented >>>>> by default it will use an empty function. >>>>> >>>>> Signed-off-by: Josh Wu >>>>> --- >>>>> >>>>> Changes in v2: new added >>>>> >>>>> arch/arm/lib/cache.c | 9 +++++++++ >>>>> 1 file changed, 9 insertions(+) >>>> So, why exactly can't this be entirely common code , but a CPU-specific >>>> code ? :) >>> Do you mean to make those empty functions as common code for all arch >>> cpu to use? >> Yes. >> >>> It seems there is no place to put common code for all arch cpu. >> Isn't that what the common/ directory is for ? ;-) > No, this is making something common for the sake of making it common > rather than good architecutre of the code I think. We aren't going to > share real cache functions just these dummy ones. So it is the right place: arch/arm/lib/cache.c to put the dummy cache function. > We may re-evaluate > our dummy ones at some point in the future when people try and use some > particular combination harder, see for example the PowerPC dummy cache > functions we just recently dropped. Thanks! > If this patch set are ok for you. I will sent more patches to drop the dummy cache functions in /cpu/ folders. Also the flush_cache() in arch/arm/lib/cache.c can be dropped and just call flush_dcache_range() as the ARM1136, ARM926ejs alreay implemented their own flush_cache(). Best Regards, Josh Wu