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
13static bool noncoherent_supported;
14
15void 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
35void 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
52void 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
59void 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
75void 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}