> Am 22.02.2016 um 18:37 schrieb york sun <york....@nxp.com>: > >> On 02/21/2016 05:57 PM, Alexander Graf wrote: >> Howdy, >> >> Currently on arm64 there is a big pile of mess when it comes to MMU >> support and page tables. Each board does its own little thing and the >> generic code is pretty dumb and nobody actually uses it. >> >> This patch set tries to clean that up. After this series is applied, >> all boards except for the FSL Layerscape ones are converted to the >> new generic page table logic and have icache+dcache enabled. >> >> The new code always uses 4k page size. It dynamically allocates 1G or >> 2M pages for ranges that fit. When a dcache attribute request comes in >> that requires a smaller granularity than our previous allocation could >> fulfill, pages get automatically split. >> >> I have tested and verified the code works on HiKey (bare metal), >> vexpress64 (Foundation Model) and zynqmp (QEMU). The TX1 target is >> untested, but given the simplicity of the maps I doubt it'll break. >> ThunderX in theory should also work, but I haven't tested it. I would >> be very happy if people with access to those system could give the patch >> set a try. >> >> With this we're a big step closer to a good base line for EFI payload >> support, since we can now just require that all boards always have dcache >> enabled. >> >> I would also be incredibly happy if some Freescale people could look >> at their MMU code and try to unify it into the now cleaned up generic >> code. I don't think we're far off here. > > Alex, > > Unified MMU will be great for all of us. The reason we started with our own > MMU > table was size and performance. I don't know much about other ARMv8 SoCs. For > our use, we enable cache very early to speed up running, especially for > pre-silicon development on emulators. We don't have DDR to use for the early > stage and we have very limited on-chip SRAM. I believe we can use the unified > structure for our 2nd stage MMU when DDR is up.
Yup, and I think it should be fairly doable to move the early generation into the same table format - maybe even fully reuse the generic code. The thing that I tripped over while attempting conversion was that you don't always map phys==virt, unless other boards, and I didn't fully understand why. Alex _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
