riscv: enable DMA_BOUNCE_UNALIGNED_KMALLOC for !dma_coherent
With the DMA bouncing of unaligned kmalloc() buffers now in place, enable it for riscv when RISCV_DMA_NONCOHERENT=y to allow the kmalloc-{8,16,32,96} caches. Since RV32 doesn't enable SWIOTLB yet, and I didn't see any dma noncoherent RV32 platforms in the mainline, so skip RV32 now by only enabling DMA_BOUNCE_UNALIGNED_KMALLOC if SWIOTLB is available. Once we see such requirement on RV32, we can enable it then. NOTE: we didn't force to create the swiotlb buffer even when the end of RAM is within the 32-bit physical address range. That's to say: For RV64 with > 4GB memory, the feature is enabled. For RV64 with <= 4GB memory, the feature isn't enabled by default. We rely on users to pass "swiotlb=mmnn,force" where mmnn is the Number of I/O TLB slabs, see kernel-parameters.txt for details. Tested on Sipeed Lichee Pi 4A with 8GB DDR and Sipeed M1S BL808 Dock board. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230718152214.2907-3-jszhang@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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@ -267,6 +267,7 @@ config RISCV_DMA_NONCOHERENT
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select ARCH_HAS_SETUP_DMA_OPS
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select ARCH_HAS_SETUP_DMA_OPS
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select ARCH_HAS_SYNC_DMA_FOR_CPU
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select ARCH_HAS_SYNC_DMA_FOR_CPU
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select ARCH_HAS_SYNC_DMA_FOR_DEVICE
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select ARCH_HAS_SYNC_DMA_FOR_DEVICE
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select DMA_BOUNCE_UNALIGNED_KMALLOC if SWIOTLB
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select DMA_DIRECT_REMAP
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select DMA_DIRECT_REMAP
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config AS_HAS_INSN
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config AS_HAS_INSN
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