riscv: Kconfig: Select DMA_DIRECT_REMAP only if MMU is enabled

kernel/dma/mapping.c has its use of pgprot_dmacoherent() inside
an #ifdef CONFIG_MMU block. kernel/dma/pool.c has its use of
pgprot_dmacoherent() inside an #ifdef CONFIG_DMA_DIRECT_REMAP block.
So select DMA_DIRECT_REMAP only if MMU is enabled for RISCV_DMA_NONCOHERENT
config.

This avoids users to explicitly select MMU.

Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20230901105111.311200-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 712ae02..d607ab0 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -273,7 +273,7 @@ config RISCV_DMA_NONCOHERENT
        select ARCH_HAS_SYNC_DMA_FOR_CPU
        select ARCH_HAS_SYNC_DMA_FOR_DEVICE
        select DMA_BOUNCE_UNALIGNED_KMALLOC if SWIOTLB
-       select DMA_DIRECT_REMAP
+       select DMA_DIRECT_REMAP if MMU
 
 config RISCV_NONSTANDARD_CACHE_OPS
        bool