1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * RISC-V specific functions to support DMA for non-coherent devices 4 * 5 * Copyright (c) 2021 Western Digital Corporation or its affiliates. 6 */ 7 8 #include <linux/dma-direct.h> 9 #include <linux/dma-map-ops.h> 10 #include <linux/mm.h> 11 #include <asm/cacheflush.h> 12 13 static bool noncoherent_supported; 14 15 void arch_sync_dma_for_device(phys_addr_t paddr, size_t size, 16 enum dma_data_direction dir) 17 { 18 void *vaddr = phys_to_virt(paddr); 19 20 switch (dir) { 21 case DMA_TO_DEVICE: 22 ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); 23 break; 24 case DMA_FROM_DEVICE: 25 ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); 26 break; 27 case DMA_BIDIRECTIONAL: 28 ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size); 29 break; 30 default: 31 break; 32 } 33 } 34 35 void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size, 36 enum dma_data_direction dir) 37 { 38 void *vaddr = phys_to_virt(paddr); 39 40 switch (dir) { 41 case DMA_TO_DEVICE: 42 break; 43 case DMA_FROM_DEVICE: 44 case DMA_BIDIRECTIONAL: 45 ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size); 46 break; 47 default: 48 break; 49 } 50 } 51 52 void arch_dma_prep_coherent(struct page *page, size_t size) 53 { 54 void *flush_addr = page_address(page); 55 56 ALT_CMO_OP(flush, flush_addr, size, riscv_cbom_block_size); 57 } 58 59 void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, 60 const struct iommu_ops *iommu, bool coherent) 61 { 62 WARN_TAINT(!coherent && riscv_cbom_block_size > ARCH_DMA_MINALIGN, 63 TAINT_CPU_OUT_OF_SPEC, 64 "%s %s: ARCH_DMA_MINALIGN smaller than riscv,cbom-block-size (%d < %d)", 65 dev_driver_string(dev), dev_name(dev), 66 ARCH_DMA_MINALIGN, riscv_cbom_block_size); 67 68 WARN_TAINT(!coherent && !noncoherent_supported, TAINT_CPU_OUT_OF_SPEC, 69 "%s %s: device non-coherent but no non-coherent operations supported", 70 dev_driver_string(dev), dev_name(dev)); 71 72 dev->dma_coherent = coherent; 73 } 74 75 void riscv_noncoherent_supported(void) 76 { 77 WARN(!riscv_cbom_block_size, 78 "Non-coherent DMA support enabled without a block size\n"); 79 noncoherent_supported = true; 80 } 81