On 06/01/2016 05:31 PM, Arnd Bergmann wrote: > On Wednesday, June 1, 2016 4:31:54 PM CEST Nishanth Menon wrote: >> Introduce ARCH_KEYSTONE_TYPICAL which is common for all Keystone >> platforms. This is particularly useful when custom optimized defconfig >> builds are created for Keystone architecture platforms. >> >> An example of the same would be a sample fragment ks_only.cfg: >> http://pastebin.ubuntu.com/16904991/ - This prunes all arch other than >> keystone and any options the other architectures may enable. >> >> git clean -fdx && git reset --hard && \ >> ./scripts/kconfig/merge_config.sh -m \ >> ./arch/arm/configs/multi_v7_defconfig ~/tmp/ks_only.cfg &&\ >> make olddefconfig >> >> The above unfortunately will disable options necessary for KS2 boards >> to boot to the bare minimum initramfs. >> >> Hence the "KEYSTONE_TYPICAL" option is designed similar to commit >> 8d9166b519fd >> ("omap2/3/4: Add Kconfig option to compile in typical omap features") >> that can be enabled for most boards keystone platforms >> without needing to rediscover these in defconfig all over again - >> examples include multi_v7_defconfig base and optimizations done on top >> of them for keystone platform. > > I'd rather remove the option for OMAP as well, it doesn't really fit in with > how we do things for other platforms, and selecting a lot of other Kconfig > symbols tends to cause circular dependencies.
Hmm, fair enough -> adding Tony as well if he sees an problem with dropping ARCH_OMAP2PLUS_TYPICAL. > >> >> NOTE: the alternative is to select the configurations under >> ARCH_KEYSTONE. However, that would fail multi_v7 builds on ARM >> variants that dont work with LPAE. > > Please no arbitrary selects from the platform. > Agreed. >> Cc: Bill Mills <wmi...@ti.com> >> Cc: Murali Karicheri <m-kariche...@ti.com> >> Cc: Grygorii Strashko <grygorii.stras...@ti.com> >> Cc: Tero Kristo <t-kri...@ti.com> >> Cc: Lokesh Vutla <lokeshvu...@ti.com> >> Signed-off-by: Nishanth Menon <n...@ti.com> >> --- >> >> Based on: next-20160601 >> >> Tested for basic initramfs boot for K2HK/K2G platforms with the >> http://pastebin.ubuntu.com/16904991/ fragment + multi_v7_defconfig >> >> Side note on LPAE: >> For our current device tree and u-boot, LPAE is mandatory to bootup >> for current Keystone boards - but this is not a SoC requirement, >> booting without LPAE/HIGHMEM results in non-coherent DDR accesses. > > This sounds like a regression, I thought we had this working when > keystone was initially merged and we got both the coherent and > non-coherent mode working with the same DT. > >> Currently: >> - U-Boot assumes that lpae is always enabled in kennel and updates the >> DT memory node with higher addresses. Because of which you are not >> detecting any memory without lpae and kernel crashed very early, hence >> no prints. So, make mem_lpae env setting as 0 in U-boot. > > We could work around this in the kernel by detecting the faulty u-boot > behavior and fixing up the addresses in an early platform callback. > >> - DT also assumes that lpae is always enabled, and always asks for >> dma-address translation for higher addresses to lower addresses. >> Just delete the "dma-ranges" property or create a one-on-one mapping >> like dma-ranges = <0x80000000 0x0 0x80000000 0x80000000> > > This may be a bit trickier, I think originally keystone ignored the > dma-ranges property and hacked up its own offset by adding a magic > constant to the dma address using a bus notifier. We probably don't > want to bring that hack back, but maybe we can come up with another > solution. > Santosh, Bill, Lokesh, Grygorii: could you help feedback on the above comments from Arnd? -- Regards, Nishanth Menon