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 <linux/of.h> 12 #include <linux/of_device.h> 13 #include <asm/cacheflush.h> 14 15 unsigned int riscv_cbom_block_size; 16 static bool noncoherent_supported; 17 18 void arch_sync_dma_for_device(phys_addr_t paddr, size_t size, 19 enum dma_data_direction dir) 20 { 21 void *vaddr = phys_to_virt(paddr); 22 23 switch (dir) { 24 case DMA_TO_DEVICE: 25 ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); 26 break; 27 case DMA_FROM_DEVICE: 28 ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size); 29 break; 30 case DMA_BIDIRECTIONAL: 31 ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size); 32 break; 33 default: 34 break; 35 } 36 } 37 38 void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size, 39 enum dma_data_direction dir) 40 { 41 void *vaddr = phys_to_virt(paddr); 42 43 switch (dir) { 44 case DMA_TO_DEVICE: 45 break; 46 case DMA_FROM_DEVICE: 47 case DMA_BIDIRECTIONAL: 48 ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size); 49 break; 50 default: 51 break; 52 } 53 } 54 55 void arch_dma_prep_coherent(struct page *page, size_t size) 56 { 57 void *flush_addr = page_address(page); 58 59 ALT_CMO_OP(flush, flush_addr, size, riscv_cbom_block_size); 60 } 61 62 void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, 63 const struct iommu_ops *iommu, bool coherent) 64 { 65 WARN_TAINT(!coherent && riscv_cbom_block_size > ARCH_DMA_MINALIGN, 66 TAINT_CPU_OUT_OF_SPEC, 67 "%s %s: ARCH_DMA_MINALIGN smaller than riscv,cbom-block-size (%d < %d)", 68 dev_driver_string(dev), dev_name(dev), 69 ARCH_DMA_MINALIGN, riscv_cbom_block_size); 70 71 WARN_TAINT(!coherent && !noncoherent_supported, TAINT_CPU_OUT_OF_SPEC, 72 "%s %s: device non-coherent but no non-coherent operations supported", 73 dev_driver_string(dev), dev_name(dev)); 74 75 dev->dma_coherent = coherent; 76 } 77 78 #ifdef CONFIG_RISCV_ISA_ZICBOM 79 void riscv_init_cbom_blocksize(void) 80 { 81 struct device_node *node; 82 unsigned long cbom_hartid; 83 u32 val, probed_block_size; 84 int ret; 85 86 probed_block_size = 0; 87 for_each_of_cpu_node(node) { 88 unsigned long hartid; 89 90 ret = riscv_of_processor_hartid(node, &hartid); 91 if (ret) 92 continue; 93 94 /* set block-size for cbom extension if available */ 95 ret = of_property_read_u32(node, "riscv,cbom-block-size", &val); 96 if (ret) 97 continue; 98 99 if (!probed_block_size) { 100 probed_block_size = val; 101 cbom_hartid = hartid; 102 } else { 103 if (probed_block_size != val) 104 pr_warn("cbom-block-size mismatched between harts %lu and %lu\n", 105 cbom_hartid, hartid); 106 } 107 } 108 109 if (probed_block_size) 110 riscv_cbom_block_size = probed_block_size; 111 } 112 #endif 113 114 void riscv_noncoherent_supported(void) 115 { 116 WARN(!riscv_cbom_block_size, 117 "Non-coherent DMA support enabled without a block size\n"); 118 noncoherent_supported = true; 119 } 120