From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Fri, 15 Jun 2012 08:20:51 -0700 Subject: [U-Boot] [PATCH 2/4] cache_v7: Check for dcache enablement in dcache flush functions In-Reply-To: References: <1339700507-26700-1-git-send-email-trini@ti.com> <1339700507-26700-3-git-send-email-trini@ti.com> <4FDB41BE.40204@ti.com> <4FDB4E0B.2060309@ti.com> Message-ID: <4FDB52D3.3090602@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 06/15/2012 08:18 AM, R, Sricharan wrote: > Hi, > [snip..] >>>>> If it is a problem with unaligned regions, then that is the only >>>>> thing to be fixed >>>>> right ?. Just trying to understand why this change is required ? >>>> >>>> The problem is that within the USB/network/filesystem stacks we have a >>>> lot of not cache safe alignments apparently. Without this every '#' of >>>> a tftp gives a screen full of error printfs. So tftp'ing a kernel takes >>>> minutes, not seconds, to complete. >>>> >>> Ok,but when buffers are not aligned >>> isn't that you are going to have coherency problems ? >> >> Exactly. USB requires dcache to be turned off today. With it turned >> off it spams these messages making tftp to an aligned address take >> minutes because the console is busy printing all of these messages about >> flushes it didn't need to do. The alternative is to build >> omap4/omap5/etc with dcache disabled or USB disabled. >> > Ok, but who is calling cache maintenance in your case after > turning off caches ? The USB stack currently. -- Tom