1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * arch/arm/include/asm/mach/dma.h 4 * 5 * Copyright (C) 1998-2000 Russell King 6 * 7 * This header file describes the interface between the generic DMA handler 8 * (dma.c) and the architecture-specific DMA backends (dma-*.c) 9 */ 10 11 struct dma_struct; 12 typedef struct dma_struct dma_t; 13 14 struct dma_ops { 15 int (*request)(unsigned int, dma_t *); /* optional */ 16 void (*free)(unsigned int, dma_t *); /* optional */ 17 void (*enable)(unsigned int, dma_t *); /* mandatory */ 18 void (*disable)(unsigned int, dma_t *); /* mandatory */ 19 int (*residue)(unsigned int, dma_t *); /* optional */ 20 int (*setspeed)(unsigned int, dma_t *, int); /* optional */ 21 const char *type; 22 }; 23 24 struct dma_struct { 25 void *addr; /* single DMA address */ 26 unsigned long count; /* single DMA size */ 27 struct scatterlist buf; /* single DMA */ 28 int sgcount; /* number of DMA SG */ 29 struct scatterlist *sg; /* DMA Scatter-Gather List */ 30 31 unsigned int active:1; /* Transfer active */ 32 unsigned int invalid:1; /* Address/Count changed */ 33 34 unsigned int dma_mode; /* DMA mode */ 35 int speed; /* DMA speed */ 36 37 unsigned int lock; /* Device is allocated */ 38 const char *device_id; /* Device name */ 39 40 const struct dma_ops *d_ops; 41 }; 42 43 /* 44 * isa_dma_add - add an ISA-style DMA channel 45 */ 46 extern int isa_dma_add(unsigned int, dma_t *dma); 47 48 /* 49 * Add the ISA DMA controller. Always takes channels 0-7. 50 */ 51 extern void isa_init_dma(void); 52