On Wed, 06 Jul 2022 16:15:32 PDT (-0700), heiko@xxxxxxxxx wrote:
This series is based on the alternatives changes done in my svpbmt series and thus also depends on Atish's isa-extension parsing series. It implements using the cache-management instructions from the Zicbom- extension to handle cache flush, etc actions on platforms needing them. SoCs using cpu cores from T-Head like the Allwinne D1 implement a different set of cache instructions. But while they are different, instructions they provide the same functionality, so a variant can easly hook into the existing alternatives mechanism on those. An ongoing discussion is about the currently used pre-coded instructions. Palmer's current thinking is that we should wait until the relevant instructions have landed in binutils. The main Zicbom instructions are in toolchains now and at least Debian also carries a binutils snapshot with it, but the T-Head variant still uses pre-coded instructions for now. The series sits on top of my svpbmt fixup series, which for example includes the conversion away from function pointers for the check-functions. It also uses my nops-series to shorten multiple nop statements: https://lore.kernel.org/r/20220607143059.1054074-1-heiko@xxxxxxxxx A new dma-noncoherent property was added for the devicetree-specification and dt-schema in: - https://www.spinics.net/lists/devicetree-spec/msg01053.html - https://github.com/devicetree-org/dt-schema/pull/78 The dtschema-patch was already merged and patch1 in this series got a reviewed-by from Rob, so I guess that new property should be ok to use. changes in v7: - add recently received review-tags - fix wrong rv32 mabi when testing for Zicbom in Kconfig changes in v6: - add recently received review-tags - adapt non-coherent patch subject as suggested by Christoph Hellwig changes in v5: - beautify of_dma_is_coherent as suggested by Christoph Hellwig - WARN_TAINT when ARCH_DMA_MINALIGN smaller than riscv,cbom-block-size (similar to how arm64 does this) - add a function to track if non-coherent handling is available - WARN_TAINT if a device is non-coherent but no non-coherent handling - use clean instead of inval in arch_sync_dma_for_device:DMA_FROM_DEVICE hopefully I understood https://lore.kernel.org/linux-arm-kernel/20220610151228.4562-1-will@xxxxxxxxxx/T/ correctly in this changes in v4: - modify of_dma_is_coherent() also handle coherent system with maybe noncoherent devices - move Zicbom to use real instructions - split off the actual dma-noncoherent code from the Zicbom extension - Don't assumes devices are non-coherent, instead default to coherent and require the non-coherent ones to be marked - CPUFEATURE_ZICBOM instead of CPUFEATURE_CMO - fix used cache addresses - drop some unused headers from dma-noncoherent.c - move unsigned long cast when calling ALT_CMO_OP - remove unneeded memset-0 - define ARCH_DMA_MINALIGN - use flush instead of inval in arch_sync_dma_for_cpu() - depend on !XIP_KERNEL - trim some line lengths - improve Kconfig description changes in v3: - rebase onto 5.19-rc1 + svpbmt-fixup-series - adapt wording for block-size binding - include asm/cacheflush.h into dma-noncoherent to fix the no-prototype error clang seems to generate - use __nops macro for readability - add some received tags - add a0 to the clobber list changes in v2: - cbom-block-size is hardware-specific and comes from firmware - update Kconfig name to use the ISA extension name - select the ALTERNATIVES symbol when enabled - shorten the line lengths of the errata-assembly Heiko Stuebner (4): of: also handle dma-noncoherent in of_dma_is_coherent() dt-bindings: riscv: document cbom-block-size riscv: Add support for non-coherent devices using zicbom extension riscv: implement cache-management errata for T-Head SoCs .../devicetree/bindings/riscv/cpus.yaml | 5 + arch/riscv/Kconfig | 31 +++++ arch/riscv/Kconfig.erratas | 11 ++ arch/riscv/Makefile | 4 + arch/riscv/errata/thead/errata.c | 20 ++++ arch/riscv/include/asm/cache.h | 4 + arch/riscv/include/asm/cacheflush.h | 10 ++ arch/riscv/include/asm/errata_list.h | 59 ++++++++- arch/riscv/include/asm/hwcap.h | 1 + arch/riscv/kernel/cpu.c | 1 + arch/riscv/kernel/cpufeature.c | 24 ++++ arch/riscv/kernel/setup.c | 2 + arch/riscv/mm/Makefile | 1 + arch/riscv/mm/dma-noncoherent.c | 112 ++++++++++++++++++ drivers/of/address.c | 17 +-- 15 files changed, 293 insertions(+), 9 deletions(-) create mode 100644 arch/riscv/mm/dma-noncoherent.c
Thanks, this is on for-next. I had to fix up a few things, nothing big but I did end up making Zicbom depend on MMU -- that's probably not strictly necessary, but it looks like the dma_noncoherent stuff pulls in some MMU dependencies. Since the only hardware that has Zicbom also has an MMU I figured it's OK for now, but happy to take an improvement if someone has one.
Since there's a new extension it also requires updating sparse, I sent a patch (linked in the merge commit).
