1,单个DMA每次只能发送一定量的数据，但对于数据源来说数据时源源不断产生的，所以在单个DMA单次发送完成至下一次传输期间，这段时间的数据流失了，所以采用两个DMA实现循环发送数据，防止数据丢失。自定义一个IP核用于产生源源不断的测试数据模拟数据源，再自定义一个IP用于切换DMA发送数据。通过axi-gpio启动数据源产生数据，数据流再通过DMA切换模块分批次将数据送往DMA。每个DMA发送20万个数据便进行切换，所以数据源采用从1开始累加产生数据，每次在DMA中断中验证最后一个数据是否正确。
2，添加驱动
在Kconfig中，发现 XILINX_DMA
config ALINX_ADC_DMA tristate "ALINX ADC DMA Test client for AXI DMA" depends on XILINX_DMA help ALINX ADC DMA client.
在Makefile中发现
obj-$(CONFIG_XILINX_DMA) += xilinx_dma.o
对应于/home/alinx/linux-xlnx-xilinx-v2017.4/drivers/dma/xilinx/xilinx_dma.c中
设备树代码 pl.dtsi
/ { amba_pl: amba_pl { #address-cells = <1>; #size-cells = <1>; compatible = "simple-bus"; ranges ; axi_dma_0: dma@40400000 { #dma-cells = <1>; clock-names = "s_axi_lite_aclk", "m_axi_s2mm_aclk"; clocks = <&clkc 15>, <&clkc 15>; compatible = "xlnx,axi-dma0"; interrupt-names = "s2mm_introut"; interrupt-parent = <&intc>; interrupts = <0 29 4>; reg = <0x40400000 0x10000>; xlnx,addrwidth = <0x20>; xlnx,sg-length-width = <0x14>; dma-channel@40400030 { compatible = "xlnx,axi-dma-s2mm-channel"; dma-channels = <0x1>; interrupts = <0 29 4>; xlnx,datawidth = <0x20>; xlnx,device-id = <0x0>; }; }; axi_dma_1: dma@40410000 { #dma-cells = <1>; clock-names = "s_axi_lite_aclk", "m_axi_s2mm_aclk"; clocks = <&clkc 15>, <&clkc 15>; compatible = "xlnx,axi-dma1"; interrupt-names = "s2mm_introut"; interrupt-parent = <&intc>; interrupts = <0 30 4>; reg = <0x40410000 0x10000>; xlnx,addrwidth = <0x20>; xlnx,sg-length-width = <0x14>; dma-channel@40410030 { compatible = "xlnx,axi-dma-s2mm-channel"; dma-channels = <0x1>; interrupts = <0 30 4>; xlnx,datawidth = <0x20>; xlnx,device-id = <0x1>; }; }; axi_gpio_0: gpio@41200000 { #gpio-cells = <3>; clock-names = "s_axi_aclk"; clocks = <&clkc 15>; compatible = "xlnx,axi-gpio-test"; gpio-controller ; reg = <0x41200000 0x10000>; xlnx,all-inputs = <0x0>; xlnx,all-inputs-2 = <0x0>; xlnx,all-outputs = <0x1>; xlnx,all-outputs-2 = <0x0>; xlnx,dout-default = <0x00000000>; xlnx,dout-default-2 = <0x00000000>; xlnx,gpio-width = <0x1>; xlnx,gpio2-width = <0x20>; xlnx,interrupt-present = <0x0>; xlnx,is-dual = <0x0>; xlnx,tri-default = <0xFFFFFFFF>; xlnx,tri-default-2 = <0xFFFFFFFF>; }; }; };
3，gpio驱动代码gpio_driver.c
#include <linux/module.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/types.h> #include <linux/ioport.h> #include <linux/interrupt.h> #include <linux/fcntl.h> #include <linux/init.h> #include <linux/poll.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> /* Needed for Sequence File Operations */ #include <linux/mutex.h> #include <linux/sysctl.h> #include <linux/fs.h> #include <linux/cdev.h> #include "linux/device.h" #include "linux/miscdevice.h" #include <linux/platform_device.h> #include <linux/clk.h> #include <linux/of_irq.h> #include <linux/slab.h> #include <linux/bitops.h> #include <linux/dmapool.h> #include <linux/of_dma.h> #include <linux/dma-mapping.h> #include <linux/kfifo.h>
#include "linux/kthread.h" #include "linux/wait.h" #include "linux/completion.h" #include "linux/workqueue.h" #include <linux/io.h> #include <linux/uaccess.h>
int major; static struct class *gpio_class = NULL; void __iomem *base_regs;
/* *open 接口函数 * * */ static int axi_gpio_open(struct inode *inode,struct file *file) { printk("enter axi_gpio_open \r\n"); return 0; } /* * write 接口函数 * * */ static int axi_gpio_write(struct file *file,const char __user *buf, size_t count,loff_t *ppos) { unsigned int ret=0; int data; printk("gpio write start !\n"); ret=copy_from_user(&data,buf,count); if(ret!=0) { printk("data read fail\n"); return -1; } iowrite32(data,base_regs);
return 0; } /* * read 接口函数 * * */ static int axi_gpio_read(struct file *file,char __user *buf,size_t size,loff_t *ppos) {
printk("gpio read start!\n"); return 0; }
static struct file_operations axi_gpio_fops={ .owner = THIS_MODULE, .read = axi_gpio_read, .write = axi_gpio_write, .open = axi_gpio_open, }; unsigned int irq_num; static int gpio_probe(struct platform_device *pdev) { struct resource *io; printk("enter gpio probe\r\n"); //从设备树中获取gpio基地址，同时进行地址映射，虚拟地址保存在 base_regs 中 io = platform_get_resource(pdev, IORESOURCE_MEM, 0); base_regs = devm_ioremap_resource(&pdev->dev, io); printk("gpio base address is: 0X:%x\r\n",base_regs); iowrite32(0x0,base_regs); major = register_chrdev( 0 , "axi_gpio_dev" , &axi_gpio_fops); gpio_class = class_create (THIS_MODULE , "axi_gpio_dev"); device_create(gpio_class, NULL, MKDEV(major,0), NULL, "axi_gpio_dev"); printk("major dev number= %d",major); return 0; } static int gpio_remove(struct platform_device *pdev) { unregister_chrdev(major,"axi_gpio_dev"); device_destroy(gpio_class,MKDEV(major,0)); class_destroy(gpio_class);
iounmap(base_regs); return 0; } static const struct of_device_id my_axigpio_of_ids[] = { { .compatible = "xlnx,axi-gpio-test",}, {} };
static struct platform_driver my_axigpio_driver = { .driver = { .name = "my_axi_gpio", .of_match_table = my_axigpio_of_ids, }, .probe = gpio_probe, .remove = gpio_remove, };
module_platform_driver(my_axigpio_driver);
MODULE_AUTHOR("TES@gpio"); MODULE_DESCRIPTION("my gpio driver"); MODULE_ALIAS("my gpio linux driver"); MODULE_LICENSE("GPL"); 4，dma驱动代码dma_driver.c
#include <linux/module.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/types.h> #include <linux/ioport.h> #include <linux/interrupt.h> #include <linux/fcntl.h> #include <linux/init.h> #include <linux/poll.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> /* Needed for Sequence File Operations */ #include <linux/mutex.h> #include <linux/sysctl.h> #include <linux/fs.h> #include <linux/cdev.h> #include "linux/device.h" #include "linux/miscdevice.h" #include <linux/platform_device.h> #include <linux/clk.h> #include <linux/of_irq.h> #include <linux/slab.h> #include <linux/bitops.h> #include <linux/dmapool.h> #include <linux/of_dma.h> #include <linux/dma-mapping.h> #include <linux/kfifo.h>
#include "linux/kthread.h" #include "linux/wait.h" #include "linux/completion.h" #include "linux/workqueue.h" #include <linux/io.h> #include <linux/uaccess.h> /** *DMA驱动程序 * * **/ //DMA MM2S控制寄存器 volatile unsigned int * mm2s_cr; #define MM2S_DMACR 0X00000000
//DMA MM2S状态控制寄存器 volatile unsigned int * mm2s_sr; #define MM2S_DMASR 0X00000004
//DMA MM2S源地址低32位 volatile unsigned int * mm2s_sa; #define MM2S_SA 0X00000018
//DMA MM2S传输长度（字节） volatile unsigned int * mm2s_len; #define MM2S_LENGTH 0X00000028
//DMA S2MM控制寄存器 volatile unsigned int * s2mm_cr; #define S2MM_DMACR 0X00000030
//DMA S2MM状态控制寄存器 volatile unsigned int * s2mm_sr; #define S2MM_DMASR 0X00000034
//DMA S2MM目标地址低32位 volatile unsigned int * s2mm_da; #define S2MM_DA 0X00000048
//DMA S2MM传输长度（字节） volatile unsigned int * s2mm_len; #define S2MM_LENGTH 0X00000058
#define DMA_BUF_SIZE 1024*1024 void __iomem *base_regs; int major; dma_addr_t phyaddr;//物理地址 char *buf;//虚拟地址 static struct class *dma_class = NULL; //DMA interrupt functions int dma_flag=0; unsigned int status=0; static int irq_cnt=0; static irqreturn_t dma0_s2mm_irq(int irq,void *dev_id) { unsigned int data; irq_cnt++; if(irq_cnt%5==0) { data = (buf[399999]<<24)|(buf[399998]<<16)|(buf[399997]<<8)|(buf[399996]); printk(" %d",data); } iowrite32(0x0000f000,base_regs + S2MM_DMASR); iowrite32(0x00001001,base_regs + S2MM_DMACR);//open int & enable DMA iowrite32(phyaddr ,base_regs + S2MM_DA); iowrite32(4000000 ,base_regs + S2MM_LENGTH);//write transmission length and DMA start transmission return IRQ_HANDLED; }
/* *open 接口函数 * * */ static int axi_dma_open(struct inode *inode,struct file *file) { printk("enter axi_dma_open \r\n"); iowrite32(0x00001001,base_regs + S2MM_DMACR);//open int & enable DMA iowrite32(phyaddr ,base_regs + S2MM_DA); iowrite32(400000 ,base_regs + S2MM_LENGTH);//write transmission length and DMA start transmission return 0; } /* * write 接口函数 * * */ static int axi_dma_write(struct file *file,const char __user *buff, size_t count,loff_t *ppos) {
printk("dma write start !\n"); return 0; } /* * read 接口函数 * * */ static int axi_dma_read(struct file *file,char __user *buff,size_t size,loff_t *ppos) {
printk("dma read start !\n"); return 0; } static unsigned int axi_dma_poll(struct file *file, poll_table *wait) { printk("enter axi_dma_poll \r\n"); return 0; } static int axi_dma_mmap (struct file *file, struct vm_area_struct *vma) { printk("enter axi_dma_mmap \r\n"); vma->vm_flags |= VM_IO; vma->vm_flags |= VM_LOCKED; vma->vm_pgoff = phyaddr >> PAGE_SHIFT; vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
if(remap_pfn_range(vma, vma->vm_start,vma->vm_pgoff, vma->vm_end-vma->vm_start, vma->vm_page_prot)){ printk("axi_dma_mmap failed.\n"); return -EAGAIN; } printk("base start=0xlx, \n",(unsigned long)phyaddr); printk("vma start=0xlx, size=%ld.\n", (unsigned long)vma->vm_start, (unsigned long)vma->vm_end - (unsigned long)vma->vm_start); return 0; } static struct file_operations axi_dma_fops={ .owner = THIS_MODULE, .read = axi_dma_read, .write = axi_dma_write, .open = axi_dma_open, .mmap = axi_dma_mmap, /* mmap method */ }; unsigned int irq_num; static int my_dma_probe(struct platform_device *pdev) { struct resource *io; struct device_node *node = pdev->dev.of_node; struct device_node *child; int err; struct device *dev; //从设备树中获取dma基地址，同时进行地址映射，虚拟地址保存在 base_regs 中 io = platform_get_resource(pdev, IORESOURCE_MEM, 0); base_regs = devm_ioremap_resource(&pdev->dev, io); printk("dma base address is: 0X:%x\r\n",base_regs); //申请中断 for_each_child_of_node(node, child){ if(of_device_is_compatible(child, "xlnx,axi-dma-s2mm-channel")) { printk("axi dma s2mm valid\r\n"); irq_num = irq_of_parse_and_map(child, 0); err = request_irq(irq_num, dma0_s2mm_irq, IRQF_TRIGGER_RISING, "dma0_s2mm_irq", NULL); if (err) { printk( "dma0 unable to request IRQ %d\n", irq_num); return err; } } else { printk("dma0 Invalid channel compatible node\n"); return -EINVAL; } } ///申请dma缓冲区--起始 dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL); if (!dev) return -ENOMEM; dev = &pdev->dev; dev->coherent_dma_mask = 0xffffffff; buf = dma_alloc_coherent(dev, PAGE_ALIGN(DMA_BUF_SIZE), &phyaddr, GFP_KERNEL); if(!buf) { printk("axi vdma buffer memory allocation failed\r\n"); return -ENOMEM; } else { printk("buf=0x%x\n",buf); printk(" phyaddr=0x%x\r\n",phyaddr); } ///申请dma缓冲区--结束 major = register_chrdev( 0 , "axi_dma0_dev" , &axi_dma_fops); dma_class = class_create (THIS_MODULE , "axi_dma0_dev"); device_create(dma_class, NULL, MKDEV(major,0), NULL, "axi_dma0_dev"); printk("major dev number= %d",major); return 0; } static int my_dma_remove(struct platform_device *pdev) { unregister_chrdev(major,"axi_dma0_dev"); device_destroy(dma_class,MKDEV(major,0)); class_destroy(dma_class); free_irq(irq_num,NULL); dma_free_coherent(NULL, PAGE_ALIGN(DMA_BUF_SIZE), buf, phyaddr); iounmap(base_regs); return 0; } static const struct of_device_id my_dma_of_ids[] = { { .compatible = "xlnx,axi-dma0",}, {} };
static struct platform_driver my_dma_driver = { .driver = { .name = "my_axi_dma0", .of_match_table = my_dma_of_ids, }, .probe = my_dma_probe, .remove = my_dma_remove, };
module_platform_driver(my_dma_driver);
MODULE_AUTHOR("TEST@dma0"); MODULE_DESCRIPTION("dma0 driver"); MODULE_ALIAS("dma0 linux driver"); MODULE_LICENSE("GPL");
5，测试文件 test_my_dma.c
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <assert.h> #include <getopt.h> #include <fcntl.h> #include <unistd.h> #include <errno.h> #include <malloc.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/time.h> #include <sys/mman.h> #include <sys/ioctl.h>
#define DMA_BUF_SIZE 1024*1024
void delay() { int i=0,j=0; for(i=0;i<10000;i++) for(j=0;j<1000;j++)j++; } int main() { int dma0_fd,dma1_fd,gpio_fd; int i=0,j=0; unsigned int * dma0_mmapBuf; unsigned int * dma1_mmapBuf; int dma0_flag,dma1_flag,gpio_flag; int *dest; dma0_fd = open("/dev/axi_dma0_dev", O_RDWR, 0); if (dma0_fd < 0) { printf("Open %s failed\n", "/dev/axivdma_dev"); return -1; } dma0_mmapBuf = mmap(NULL, DMA_BUF_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, dma0_fd, 0); dma1_fd = open("/dev/axi_dma1_dev", O_RDWR, 0); if (dma1_fd < 0) {
printf("Open %s failed\n", "/dev/axivdma_dev");
return -1;
} dma1_mmapBuf = mmap(NULL, DMA_BUF_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, dma1_fd, 0);
gpio_fd = open("/dev/axi_gpio_dev", O_RDWR, 0); if (gpio_fd < 0) { printf("Open %s failed\n", "/dev/axi_gpio_dev"); return -1; } gpio_flag=1; printf("======start====\r\n");
delay();
write(gpio_fd,&gpio_flag,4);
delay();
while(1);
printf("dma test Done.\n");
return 0;
}
