On Tue, Sep 20, 2016 at 2:31 PM, Alexander Graf <ag...@suse.de> wrote: > > > On 20.09.16 10:45, Thomas Abraham wrote: >> On Tue, Sep 20, 2016 at 12:03 PM, Alexander Graf <ag...@suse.de> wrote: >>> >>> >>> On 20.09.16 08:25, Thomas Abraham wrote: >>>> On Tue, Sep 20, 2016 at 11:35 AM, Alexander Graf <ag...@suse.de> wrote: >>>>> >>>>> >>>>> Am 20.09.2016 um 07:51 schrieb Thomas Abraham <ta.oma...@gmail.com>: >>>>> >>>>> Hi Alison, >>>>> >>>>> >>>>> On Mon, Sep 19, 2016 at 7:38 PM, Alexander Graf <ag...@suse.de> wrote: >>>>> >>>>> >>>>> >>>>> On 09.09.16 10:48, Alison Wang wrote: >>>>> >>>>> This patch is to use the the generic lowlevel_init instead of the >>>>> >>>>> specific one. >>>>> >>>>> >>>>> Signed-off-by: Alison Wang <alison.w...@nxp.com> >>>>> >>>>> >>>>> If I had to guess, I'd think they only had their own version because the >>>>> >>>>> old one required a GIC. >>>>> >>>>> >>>>> I apologize for the delay. >>>>> >>>>> The reason for using a custom version was to avoid enabling >>>>> ARMV8_MULTIENTRY config option since the Exynos7 code was ready for >>>>> it. >>>>> >>>>> >>>>> Either way, since Samsung doesn't reply, I'm fine potentially breaking >>>>> >>>>> their boards if that means that we can make progress for actively >>>>> >>>>> maintained ones: >>>>> >>>>> >>>>> Reviewed-by: Alexander Graf <ag...@suse.de> >>>>> >>>>> >>>>> This patch without the ARMV8_MULTIENTRY and ARMV8_SWITCH_TO_EL1 config >>>>> options does not switch the boot CPU from EL3 to EL1. So it would be >>>>> preferable to not merge this patch until ARMV8_MULTIENTRY is enabled >>>>> for Exynos7. >>>>> >>>>> >>>>> Why do you want to switch it to EL1 in the first place? Linux is very >>>>> happy >>>>> to live in EL2 - which is what we call it in by default. >>>> >>>> Okay, there is no particular requirement to be in EL1 for Exynos7. EL2 >>>> would also be fine. But Exynos7 support in u-boot is not yet ready for >>>> enabling ARMV8_MULTIENTRY config option. Is there anything be blocked >>>> due to Exynos7 using a custom lowlevel_init function? >>> >>> Yes, we're changing the semantics of armv8_switch_to_el2 and >>> armv8_switch_to_el1: >>> >>> http://lists.denx.de/pipermail/u-boot/2016-September/266217.html >>> >>> which is a prerequisite for AArch32 kernel boot on AArch64 systems. >> >> Okay. >> >>> >>> How quickly do you think you could make Exynos7 work with MULTIENTRY? >>> >> >> Exynos7420 uses CPU 0 of Cluster 1 as boot CPU (master CPU). The macro >> 'branch_if_master' requires all affinity values to be zero for a CPU >> to be identified as a master CPU. And so the boot CPU is incorrectly >> detected as a slave CPU. I have tested with the following temporary >> workaround to enable ARMV8_MULTIENTRY on Exynos7420. If it looks fine, >> this can be merged along with Alison's patch. > > That certainly works for me. Is there a particular reason why you want > to do the EL1 switch? I would strongly prefer if we could just enter OSs > in EL2 always.
There is no particular reason for EL1 switch for Exynos7420. The ARMV8_SWITCH_TO_EL1 config option can be removed, that sneaked in accidentally into the diff. Thomas. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
