From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> Add helper functions for cache wback/inval/clean and use them arch_sync_dma_for_device()/arch_sync_dma_for_cpu() functions. The proposed changes are in preparation for switching over to generic implementation. Reorganization of the code is based on the patch (Link[0]) from Arnd. For now I have dropped CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU check as this will be enabled by default upon selection of RISCV_DMA_NONCOHERENT and also dropped arch_dma_mark_dcache_clean(). Link[0]: https://lore.kernel.org/all/20230327121317.4081816-22-arnd@xxxxxxxxxx/ Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> --- Hi Arnd, I have kept the changes minimal here as compared to your original patch and dropped arch_dma_mark_dcache_clean() function and config checks for now as we are currently implementing for riscv only. Cheers, Prabhakar v3: * New patch --- arch/riscv/mm/dma-noncoherent.c | 60 ++++++++++++++++++++++++++++----- 1 file changed, 51 insertions(+), 9 deletions(-) diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c index fc6377a64c8d..06b8fea58e20 100644 --- a/arch/riscv/mm/dma-noncoherent.c +++ b/arch/riscv/mm/dma-noncoherent.c @@ -12,21 +12,61 @@ static bool noncoherent_supported __ro_after_init; -void arch_sync_dma_for_device(phys_addr_t paddr, size_t size, - enum dma_data_direction dir) +static inline void arch_dma_cache_wback(phys_addr_t paddr, size_t size) +{ + void *vaddr = phys_to_virt(paddr); + + ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); +} + +static inline void arch_dma_cache_inv(phys_addr_t paddr, size_t size) +{ + void *vaddr = phys_to_virt(paddr); + + ALT_CMO_OP(inval, vaddr, size, riscv_cbom_block_size); +} + +static inline void arch_dma_cache_wback_inv(phys_addr_t paddr, size_t size) { void *vaddr = phys_to_virt(paddr); + ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size); +} + +static inline bool arch_sync_dma_clean_before_fromdevice(void) +{ + return true; +} + +static inline bool arch_sync_dma_cpu_needs_post_dma_flush(void) +{ + return true; +} + +void arch_sync_dma_for_device(phys_addr_t paddr, size_t size, + enum dma_data_direction dir) +{ switch (dir) { case DMA_TO_DEVICE: - ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); + arch_dma_cache_wback(paddr, size); break; + case DMA_FROM_DEVICE: - ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); - break; + if (!arch_sync_dma_clean_before_fromdevice()) { + arch_dma_cache_inv(paddr, size); + break; + } + fallthrough; + case DMA_BIDIRECTIONAL: - ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); + /* Skip the invalidate here if it's done later */ + if (IS_ENABLED(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) && + arch_sync_dma_cpu_needs_post_dma_flush()) + arch_dma_cache_wback(paddr, size); + else + arch_dma_cache_wback_inv(paddr, size); break; + default: break; } @@ -35,15 +75,17 @@ void arch_sync_dma_for_device(phys_addr_t paddr, size_t size, void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size, enum dma_data_direction dir) { - void *vaddr = phys_to_virt(paddr); - switch (dir) { case DMA_TO_DEVICE: break; + case DMA_FROM_DEVICE: case DMA_BIDIRECTIONAL: - ALT_CMO_OP(inval, vaddr, size, riscv_cbom_block_size); + /* FROM_DEVICE invalidate needed if speculative CPU prefetch only */ + if (arch_sync_dma_cpu_needs_post_dma_flush()) + arch_dma_cache_inv(paddr, size); break; + default: break; } -- 2.34.1
