1// SPDX-License-Identifier: GPL-2.0+ 2/* 3 * Generic bounce buffer implementation 4 * 5 * Copyright (C) 2012 Marek Vasut <marex@denx.de> 6 */ 7 8#include <common.h> 9#include <cpu_func.h> 10#include <log.h> 11#include <malloc.h> 12#include <errno.h> 13#include <bouncebuf.h> 14#include <asm/cache.h> 15#include <linux/dma-mapping.h> 16 17static int addr_aligned(struct bounce_buffer *state) 18{ 19 const ulong align_mask = ARCH_DMA_MINALIGN - 1; 20 21 /* Check if start is aligned */ 22 if ((ulong)state->user_buffer & align_mask) { 23 debug("Unaligned buffer address %p\n", state->user_buffer); 24 return 0; 25 } 26 27 /* Check if length is aligned */ 28 if (state->len != state->len_aligned) { 29 debug("Unaligned buffer length %zu\n", state->len); 30 return 0; 31 } 32 33 /* Aligned */ 34 return 1; 35} 36 37int bounce_buffer_start_extalign(struct bounce_buffer *state, void *data, 38 size_t len, unsigned int flags, 39 size_t alignment, 40 int (*addr_is_aligned)(struct bounce_buffer *state)) 41{ 42 state->user_buffer = data; 43 state->bounce_buffer = data; 44 state->len = len; 45 state->len_aligned = roundup(len, alignment); 46 state->flags = flags; 47 48 if (!addr_is_aligned(state)) { 49 state->bounce_buffer = memalign(alignment, 50 state->len_aligned); 51 if (!state->bounce_buffer) 52 return -ENOMEM; 53 54 if (state->flags & GEN_BB_READ) 55 memcpy(state->bounce_buffer, state->user_buffer, 56 state->len); 57 } 58 59 /* 60 * Flush data to RAM so DMA reads can pick it up, 61 * and any CPU writebacks don't race with DMA writes 62 */ 63 dma_map_single(state->bounce_buffer, 64 state->len_aligned, 65 DMA_BIDIRECTIONAL); 66 67 return 0; 68} 69 70int bounce_buffer_start(struct bounce_buffer *state, void *data, 71 size_t len, unsigned int flags) 72{ 73 return bounce_buffer_start_extalign(state, data, len, flags, 74 ARCH_DMA_MINALIGN, 75 addr_aligned); 76} 77 78int bounce_buffer_stop(struct bounce_buffer *state) 79{ 80 if (state->flags & GEN_BB_WRITE) { 81 /* Invalidate cache so that CPU can see any newly DMA'd data */ 82 dma_unmap_single((dma_addr_t)(uintptr_t)state->bounce_buffer, 83 state->len_aligned, 84 DMA_BIDIRECTIONAL); 85 } 86 87 if (state->bounce_buffer == state->user_buffer) 88 return 0; 89 90 if (state->flags & GEN_BB_WRITE) 91 memcpy(state->user_buffer, state->bounce_buffer, state->len); 92 93 free(state->bounce_buffer); 94 95 return 0; 96} 97