On Tue, Jan 06 2015 at 02:35:28 PM, Rob Herring <robherri...@gmail.com> wrote: > On Tue, Jan 6, 2015 at 2:16 PM, Mitchel Humpherys > <mitch...@codeaurora.org> wrote: >> On Tue, Jan 06 2015 at 06:15:07 AM, Will Deacon <will.dea...@arm.com> wrote: >>>> /* Invalidate the TLB, just in case */ >>>> - writel_relaxed(0, gr0_base + ARM_SMMU_GR0_STLBIALL); >>>> writel_relaxed(0, gr0_base + ARM_SMMU_GR0_TLBIALLH); >>>> writel_relaxed(0, gr0_base + ARM_SMMU_GR0_TLBIALLNSNH); >>> >>> I was slightly worried that this would break the Calxeda implementation >>> with ARM_SMMU_OPT_SECURE_CFG_ACCESS, but actually these registers aren't >>> even aliased there so I think there's a bigger bug for them. >>> >>> Anyway, given that their hardware has gone the way of the dodo, I'll take >>> the patch as-is unless you have any further comments? >>> >>> Will >> >> Yeah I agree that this shouldn't affect the (now defunct) Calxeda >> implementation. I've tested this on some hardware here and we crash >> when we touch that register since it's secure-only (not banked, as you >> mentioned). > > It's not quite dead: > > http://www.eweek.com/servers/calxedas-arm-based-server-chips-re-emerge-with-new-company.html > > But AFAIK, production systems don't enable the SMMU, but someone could > still want to at some point. A note in the commit log here would be > nice so it gets recorded.
Actually, as Will mentioned this shouldn't affect Calxeda since this isn't a banked register. I think the confusion is from the `S' prefix in the spec. The /s/ (lower-case, italic) prefix means that there are secure and non-secure versions of the register, while the S (upper-case, non-italic) prefix means "this is a secure register" (which may or may not have a banked non-secure counterpart). This particular register is an S-only register (there's no non-secure counterpart) so the Calxeda workaround isn't relevant here, AFAICT. -Mitch -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
