On Tuesday, July 01, 2014 at 05:16:26 PM, Stephen Warren wrote: > On 07/01/2014 09:13 AM, Marek Vasut wrote: > > On Tuesday, July 01, 2014 at 05:03:17 PM, Stephen Warren wrote: > >> On 06/30/2014 06:04 PM, Marek Vasut wrote: > >>> Instead of weird allocation of ci_drv->items_mem and then even weirder > >>> distribution of offsets in this memory area into ci_drv->items array, > >>> just allocate ci_drv->items as a big slab of aligned memory (replaces > >>> ci_drv->items_mem) and let ci_get_qtd() do the distribution of offsets > >>> in this memory area. > >> > >> As I mentioned on IRC, this patch isn't correct. > >> > >> The existing code ensures that each pair of QTDs are correctly aligned, > >> hence the slight complexity. The new code only actively ensures that the > >> first QTD is correctly aligned; the subsequent QTDs will only be > >> correctly aligned if the sizeof the QTD structure is an exact multiple > >> of the alignment requirements. In practice, it is on my system at least, > >> but that may not be generally true. > > > > It is on every system with 32b cachelines. > > Sure. > > > On system with 64b cachelines, you > > won't be able to use one endpoint as both in and out, which I don't think > > is doable now either. > > Yes, the 2nd QTD in each pair isn't correctly aligned at present for > 64byte cachelines. I was thinking about sending a patch to fix that > (perhaps theoretical) issue.
Ah bah, you're right. > Actually, I wonder if that's related to Jörg's issue at all; his system > has the cache line size set to 64 even though that's incorrect, perhaps > that influences the behaviour of the cache code... My understanding of his test is that he uses u-boot-usb/master + this patch and there are not modifications to the CPU support code. If there are, then his test is useless of course. With u-boot-usb/master + this patch , on MX28 there should be no problem. Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
