From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?Andreas_Bie=DFmann?= Date: Tue, 09 Jul 2013 17:18:32 +0200 Subject: [U-Boot] [RFC] ARM: omap3: Add option to disable errata workarounds. In-Reply-To: <51DC25AC.7000507@andin.de> References: <1373356832-28983-1-git-send-email-anaumann@ultratronik.de> <51DBC4EA.4090104@andin.de> <20130709111040.77d19940@lilith> <51DBE913.20202@gmail.com> <51DC25AC.7000507@andin.de> Message-ID: <51DC29C8.7060603@gmail.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 Andreas, On 07/09/2013 05:01 PM, Andreas Naumann wrote: >>>> It seems that all three ARM errata workarounds done in omap3 board-init >>>> (#454179 #430973 #621766) are solved/not longer needed e.g. in the >>>> AM/DM37xx chips. Other people have noticed this: >>>> http://e2e.ti.com/support/arm/sitara_arm/f/791/t/254742.aspx >>>> >>>> When still applying them (especcially #430973), lots of segmentations >>>> faults and other strange stuff begin to appear. >> >> I read your link the other way round. If the #430973 errata fix is _not_ >> applied to r3p2 it gives a lot of segfaults. Unfortunately the thread >> has noc more information on that. > > I dont know what bootloader the guy used, but he states that he needs to > enable the errata fix in the kernel for the segfaults to disappear. I > found exactly the same: Initially I had no errata fixes configured for > the kernel, only when I added them the segfaults disappeared. > However they also disappear if I remove the workarounds from kernel as > well as u-boot, hence this patch. Ok, understand. >> I join Albert's suggestion. Another solution could be to read the >> silicon revision and enable erratum workarounds on that information. It >> would be a step towards single binary. > > So I'd rather do that, but can we map the ARM revision e.g. r2p1 to the > TI die versions ES1.0, 1.1 and so on? Or can the ARM revision be read > directly? You should use the ARM revisions. They are available, but dunno how: ---8<--- ~ cat /proc/cpuinfo Processor : ARMv7 Processor rev 2 (v7l) BogoMIPS : 512.57 Features : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x3 CPU part : 0xc08 CPU revision : 2 --->8--- AFAIK is CPU variant 'r3' and CPU revision 'p2' for this cpuinfo. Regards Andreas Bie?mann