On Tue, Jun 28, 2016 at 1:42 PM, dongbo (E) <dongbo4@xxxxxxxxxx> wrote: > > From: Dong Bo <dongbo4@xxxxxxxxxx> > > In designware PCIe driver, the iatu0 is used for both CFG and IO accesses. > When sending CFGs to peripherals (e.g. lspci), iatu0 frequently switches > between CFG and IO alternatively. > > A MEMORY probably be sent as an IOs by mistake. Considering the following > configurations: > MEMORY -> BASE_ADDR: 0xb4100000, LIMIT: 0xb4100FFF, TYPE=mem > CFG -> BASE_ADDR: 0xb4000000, LIMIT: 0xb4000FFF, TYPE=cfg > IO -> BASE_ADDR: 0xFFFFFFFF, LIMIT: 0xFFFFFFFE, TYPE=io > > Suppose PCIe has just completed a CFG access, to switch back to IO, it set > the BASE_ADDR to 0xFFFFFFFF, LIMIT 0xFFFFFFFE and TYPE to io. When another > CFG comes, the BASE_ADDR is set to 0xb4000000 to switch to CFG. At this > moment, a MEMORY access shows up, since it matches with iatu0 > (due to 0xb4000000 <= MEMORY BASE_ADDR <= MEMORY LIMIE <= 0xFFFFFFF), it > is treated as an IO access by mistake, then sent to perpheral. > > This patch fixes the problem by exchanging the assignments of `MEMORYs' > and `CFGs/IOs', which assigning MEMEORYs to iatu0, CFGs and IOs to iatu1. Had a re-thought on it. While it will fix wrong memory access in your case, it can still cause issues with IO access for some other platform. Can you please test [1] and check it that works for you. You will need to define num-viewport in your device tree file. ~Pratyush [1] https://github.com/pratyushanand/linux/commit/131b83ea7db0834d77ee5df65c6696bccbf8a1ce -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
