| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * RISC-V specific functions to support DMA for non-coherent devices |
| * |
| * Copyright (c) 2021 Western Digital Corporation or its affiliates. |
| */ |
| |
| #include <linux/dma-direct.h> |
| #include <linux/dma-map-ops.h> |
| #include <linux/mm.h> |
| #include <asm/cacheflush.h> |
| |
| static bool noncoherent_supported __ro_after_init; |
| int dma_cache_alignment __ro_after_init = ARCH_DMA_MINALIGN; |
| EXPORT_SYMBOL_GPL(dma_cache_alignment); |
| |
| void arch_sync_dma_for_device(phys_addr_t paddr, size_t size, |
| enum dma_data_direction dir) |
| { |
| void *vaddr = phys_to_virt(paddr); |
| |
| switch (dir) { |
| case DMA_TO_DEVICE: |
| ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); |
| break; |
| case DMA_FROM_DEVICE: |
| ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); |
| break; |
| case DMA_BIDIRECTIONAL: |
| ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size); |
| break; |
| default: |
| break; |
| } |
| } |
| |
| 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(flush, vaddr, size, riscv_cbom_block_size); |
| break; |
| default: |
| break; |
| } |
| } |
| |
| void arch_dma_prep_coherent(struct page *page, size_t size) |
| { |
| void *flush_addr = page_address(page); |
| |
| ALT_CMO_OP(flush, flush_addr, size, riscv_cbom_block_size); |
| } |
| |
| void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, |
| const struct iommu_ops *iommu, bool coherent) |
| { |
| WARN_TAINT(!coherent && riscv_cbom_block_size > ARCH_DMA_MINALIGN, |
| TAINT_CPU_OUT_OF_SPEC, |
| "%s %s: ARCH_DMA_MINALIGN smaller than riscv,cbom-block-size (%d < %d)", |
| dev_driver_string(dev), dev_name(dev), |
| ARCH_DMA_MINALIGN, riscv_cbom_block_size); |
| |
| WARN_TAINT(!coherent && !noncoherent_supported, TAINT_CPU_OUT_OF_SPEC, |
| "%s %s: device non-coherent but no non-coherent operations supported", |
| dev_driver_string(dev), dev_name(dev)); |
| |
| dev->dma_coherent = coherent; |
| } |
| |
| void riscv_noncoherent_supported(void) |
| { |
| WARN(!riscv_cbom_block_size, |
| "Non-coherent DMA support enabled without a block size\n"); |
| noncoherent_supported = true; |
| } |
| |
| void __init riscv_set_dma_cache_alignment(void) |
| { |
| if (!noncoherent_supported) |
| dma_cache_alignment = 1; |
| } |