Unverified Commit 93573016 authored by Lad Prabhakar's avatar Lad Prabhakar Committed by Palmer Dabbelt
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riscv: dma-mapping: switch over to generic implementation 

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@kernel.org/


Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarLad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20230816232336.164413-4-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 482069eb

arch/riscv/mm/dma-noncoherent.c

+51 −9
Original line number Diff line number Diff line
@@ -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);

		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;

	}