From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Thompson Date: Wed, 14 Sep 2011 12:07:26 +0100 Subject: [U-Boot] [PATCH 1/5] da830: disable cache usage due to coherency issues In-Reply-To: References: <1314706560-12773-1-git-send-email-nagabhushana.netagunte@ti.com> <1314706560-12773-2-git-send-email-nagabhushana.netagunte@ti.com> <201108301115.59371.vapier@gentoo.org> <4E5E0157.5090000@ge.com> Message-ID: <4E708AEE.4050508@ge.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 14/09/11 06:54, Netagunte, Nagabhushana wrote: > Nick, > > I am seeing this issue on da830/da850/dm36x/dm644x. Strange that I have seen no issue with da830 (OMAP-L137 v1.0 & v1.1 - don't have any v2.0 yet) when tftp'ing the kernel. I do get very occasional errors, but have put this down to network packet loss. The v1.0 and v1.1 parts do have a d-cache errata, so we only get to use the d-cache in write through mode. This would mean that TCP packet data writes by the processor would never have a coherency problem. Reads could still have an issue, but I think the explanation provided so far referred to TCP packet sending...? This vintage of da830 will always have to use write trough mode, so there should be no issue...? > I agree that u-boot will be faster with cache enabled. And also, TI wants it to be enabled soon. Since so many patches are lined u, we don't up-streaming them to get hampered because of this issue. So, we are trying to push this > Patch. We are committed come up with appropriate patch to fix the EMAC and coherency issue. > > Meanwhile, we are trying to gather info about earlier patch/changes which disabled cache so that community understands the known issue. Boot time is critical to us. I can't ship without cache enabled. I can use my own _config.h of course to work around it I think, but I don't understand why you think there is an issue to fix on da830 yet. With a working d-cache I can imagine such a problem though. > Also, one more engineer observed the issue with EMAC, I will send his mail to you. > > Regards, > Nag > On Wed, Aug 31, 2011 at 15:09:35, Nick Thompson wrote: >> On 31/08/11 06:40, Netagunte, Nagabhushana wrote: >>> Mike, >>> >>> We will address cache coherency issues soon after these patches. >>> Earlier also, chache was disabled. Only due to new cache management Framework which was added recently, it is explicitly needed to be indicated to turn off cache. >>> >>> Since fixing the cache coherency issues with EMAC will take some time, I want this patch to go in mainline so that issue doesn't crop up for People who use u-boot. >>> >>> Regards, >>> Nag >>> >> Which device(s) does this occur on? I have a lot of OMAP-L137 (EVM and custom) boards with cache enabled and no problems tftp'ing the kernel. >> >> On the other hand tftp and kernel CRC checking are much faster with cache enabled. >> >> Nick. >>