Skip to content

Instantly share code, notes, and snippets.

@lp6m lp6m/dma.h
Created May 24, 2019

What would you like to do?
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/mman.h>
#define DMA_INTAKE_DMACR (0x0000)
#define DMA_INTAKE_DMASR (0x0004)
#define DMA_INTAKE_SA (0x0018)
#define DMA_INTAKE_LENGTH (0x0028)
#define DMA_OUTLET_DMACR (0x0030)
#define DMA_OUTLET_DMASR (0x0034)
#define DMA_OUTLET_DA (0x0048)
#define DMA_OUTLET_LENGTH (0x0058)
#define DMA_CR_RS (1u<<0)
#define DMA_CR_RESET (1u<<2)
#define DMA_SR_HALTED (1u<<0)
#define DMA_SR_IDLE (1u<<1)
#define DMA_SR_IOC_Irq (1u<<12)
#define DMA_SR_ERR_Irq (1u<<14)
static inline uint32_t regs_read32(void* addr){
volatile uint32_t* regs_addr = (uint32_t*)(addr);
return *regs_addr;
static inline void regs_write32(void* addr, uint32_t data){
volatile uint32_t* regs_addr = (uint32_t*)(addr);
*regs_addr = data;
static inline void dma_reset(void* regs){
regs_write32(regs + DMA_INTAKE_DMACR, DMA_CR_RESET);
while(regs_read32(regs + DMA_INTAKE_DMACR) & DMA_CR_RESET);
regs_write32(regs + DMA_OUTLET_DMASR, DMA_CR_RESET);
while(regs_read32(regs + DMA_OUTLET_DMACR) & DMA_CR_RESET);
static inline void dma_setup(void* regs, unsigned long src_addr, unsigned long dst_addr){
regs_write32(regs + DMA_OUTLET_DMACR, DMA_CR_RS);
regs_write32(regs + DMA_OUTLET_DA, dst_addr);
regs_write32(regs + DMA_INTAKE_DMACR, DMA_CR_RS);
regs_write32(regs + DMA_INTAKE_SA, src_addr);
static inline void dma_intake_start(void* regs, unsigned int xfer_size){
regs_write32(regs + DMA_INTAKE_LENGTH, xfer_size);
static inline void dma_outlet_start(void* regs, unsigned int xfer_size){
regs_write32(regs + DMA_OUTLET_LENGTH, xfer_size);
static inline void dma_wait_irq(void* regs){
while(~regs_read32(regs + DMA_INTAKE_DMASR) & DMA_SR_IOC_Irq);
while(~regs_read32(regs + DMA_OUTLET_DMASR) & DMA_SR_IOC_Irq);
static inline void dma_clear_status(void* regs){
regs_write32(regs + DMA_INTAKE_DMASR, DMA_SR_IOC_Irq | DMA_SR_ERR_Irq);
regs_write32(regs + DMA_OUTLET_DMASR, DMA_SR_IOC_Irq | DMA_SR_ERR_Irq);
struct udmabuf{
char name[128];
int file;
unsigned char* buf;
unsigned int buf_size;
unsigned long phys_addr;
unsigned long debug_vma;
unsigned long sync_mode;
int udmabuf_open(struct udmabuf* udmabuf, const char* name);
int udmabuf_close(struct udmabuf* udmabuf);
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.