On Monday 08 February 2010, Måns Rullgård wrote: > Siarhei Siamashka <siarhei.siamas...@gmail.com> writes: > > On Sunday 07 February 2010, Tom wrote: > >> Siarhei Siamashka wrote: > >> > 725233: PLD instructions executed with PLD data forwarding > >> > enabled can result in a processor deadlock > >> > > >> > Signed-off-by: Siarhei Siamashka <siarhei.siamas...@gmail.com> > >> > >> Please add a detailed comment on the errata. > > > > The short summary is pretty much complete (PLD data forwarding is not > > working correctly and needs to be turned off to prevent problems). Though > > it really makes sense to add that: > > 1. only r1pX revisions of Cortex-A8 are affected > > 2. performance impact is practically non-existant > > > > The detailed description of this erratum is available in the official > > Cortex-A8 errata list. I'm not sure about directly copying full erratum > > description text here. Anyway, this workaround would be better submitted > > by somebody TI. I'm just "guilty" of triggering this deadlock with some > > ARM NEON optimizations from pixman library, so feel a bit of > > responsibility for it too. > > > >> Also looks like this jumping to ROM code. > >> Can this be done without a ROM code call ? > > > > I just added it to the part of code which is already doing similar things > > (sets L1NEON and other bits from AUXCR with some icky looking assembly > > via ROM code call). Most likely it can be also done in some other way. > > L2AUX is only writable in secure mode, which on GP devices implies > using a ROM call. Nothing wrong with that.
OK, thanks for the clarification. Can I add you to Acked-by field in the soon to be resubmitted patch with updated comment? I just remembered the following patch and had a doubt for a second: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=7ce236fcd6fd45b0441a2d49acb2ceb2de2e8a47 Have not tested this yet (IBE bit is set from u-boot on my beagleboard at the moment), but apparently the MCR instruction used in that kernel patch has no effect on OMAP3 and setting IBE bit in u-boot is also required for anybody who wants to have thumb support which is not totally broken. Additionally it would be nice to do something about related Cortex-A8 erratas #687067 and #454179. The status of L1 System Array Debug Register on the beagleboard is particularly interesting. Maybe it is a good time to do a full review of all the needed workarounds and update the u-boot code responsible for applying them on omap3 devices? -- Best regards, Siarhei Siamashka _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
