From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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>
---
 arch/riscv/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 468063780a93..a065abdc80e3 100644
--- 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
-- 
2.34.1

Hello:

This patch was applied to riscv/linux.git (for-next)
by Palmer Dabbelt <palmer@rivosinc.com>:

On Fri,  1 Sep 2023 11:51:11 +0100 you wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> 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.
> 
> [...]

Here is the summary with links:
  - riscv: Kconfig: Select DMA_DIRECT_REMAP only if MMU is enabled
    https://git.kernel.org/riscv/c/5bf68a586ff4

You are awesome, thank you!
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