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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 | // SPDX-License-Identifier: GPL-2.0-only /* * PowerPC version derived from arch/arm/mm/consistent.c * Copyright (C) 2001 Dan Malek (dmalek@jlc.net) * * Copyright (C) 2000 Russell King */ #include <linux/kernel.h> #include <linux/errno.h> #include <linux/types.h> #include <linux/highmem.h> #include <linux/dma-direct.h> #include <linux/dma-map-ops.h> #include <asm/tlbflush.h> #include <asm/dma.h> /* * make an area consistent. */ static void __dma_sync(void *vaddr, size_t size, int direction) { unsigned long start = (unsigned long)vaddr; unsigned long end = start + size; switch (direction) { case DMA_NONE: BUG(); case DMA_FROM_DEVICE: /* * invalidate only when cache-line aligned otherwise there is * the potential for discarding uncommitted data from the cache */ if ((start | end) & (L1_CACHE_BYTES - 1)) flush_dcache_range(start, end); else invalidate_dcache_range(start, end); break; case DMA_TO_DEVICE: /* writeback only */ clean_dcache_range(start, end); break; case DMA_BIDIRECTIONAL: /* writeback and invalidate */ flush_dcache_range(start, end); break; } } #ifdef CONFIG_HIGHMEM /* * __dma_sync_page() implementation for systems using highmem. * In this case, each page of a buffer must be kmapped/kunmapped * in order to have a virtual address for __dma_sync(). This must * not sleep so kmap_atomic()/kunmap_atomic() are used. * * Note: yes, it is possible and correct to have a buffer extend * beyond the first page. */ static inline void __dma_sync_page_highmem(struct page *page, unsigned long offset, size_t size, int direction) { size_t seg_size = min((size_t)(PAGE_SIZE - offset), size); size_t cur_size = seg_size; unsigned long flags, start, seg_offset = offset; int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE; int seg_nr = 0; local_irq_save(flags); do { start = (unsigned long)kmap_atomic(page + seg_nr) + seg_offset; /* Sync this buffer segment */ __dma_sync((void *)start, seg_size, direction); kunmap_atomic((void *)start); seg_nr++; /* Calculate next buffer segment size */ seg_size = min((size_t)PAGE_SIZE, size - cur_size); /* Add the segment size to our running total */ cur_size += seg_size; seg_offset = 0; } while (seg_nr < nr_segs); local_irq_restore(flags); } #endif /* CONFIG_HIGHMEM */ /* * __dma_sync_page makes memory consistent. identical to __dma_sync, but * takes a struct page instead of a virtual address */ static void __dma_sync_page(phys_addr_t paddr, size_t size, int dir) { struct page *page = pfn_to_page(paddr >> PAGE_SHIFT); unsigned offset = paddr & ~PAGE_MASK; #ifdef CONFIG_HIGHMEM __dma_sync_page_highmem(page, offset, size, dir); #else unsigned long start = (unsigned long)page_address(page) + offset; __dma_sync((void *)start, size, dir); #endif } void arch_sync_dma_for_device(phys_addr_t paddr, size_t size, enum dma_data_direction dir) { __dma_sync_page(paddr, size, dir); } void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size, enum dma_data_direction dir) { __dma_sync_page(paddr, size, dir); } void arch_dma_prep_coherent(struct page *page, size_t size) { unsigned long kaddr = (unsigned long)page_address(page); flush_dcache_range(kaddr, kaddr + size); } |