On Thu, Aug 17, 2023 at 12:23:35AM +0100, Prabhakar wrote: > From: Arnd Bergmann <arnd@xxxxxxxx> > > For a DMA_BIDIRECTIONAL transfer, the caches have to be cleaned > first to let the device see data written by the CPU, and invalidated > after the transfer to let the CPU see data written by the device. > > riscv also invalidates the caches before the transfer, which does > not appear to serve any purpose. > > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> > Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> > Acked-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx> > Acked-by: Guo Ren <guoren@xxxxxxxxxx> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> > --- > v2->v3 > * No change > > v1->v2 > * Included RB and ACKs > --- > arch/riscv/mm/dma-noncoherent.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c > index 94614cf61cdd..fc6377a64c8d 100644 > --- a/arch/riscv/mm/dma-noncoherent.c > +++ b/arch/riscv/mm/dma-noncoherent.c > @@ -25,7 +25,7 @@ void arch_sync_dma_for_device(phys_addr_t paddr, size_t size, > ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); > break; > case DMA_BIDIRECTIONAL: > - ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size); > + ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); The code could be simplified a lot since after this patch, the action is always "clean". Thanks > break; > default: > break; > -- > 2.34.1 >
