ZYNQ linux下AXI_BRAM的使用方法，PS与PL端数据交互

╰半夏微凉° 2023-07-20 13:56 2阅读 0赞

1、**AXI总线、AXI接口、AXI协议**  
总线是一组传输通道，是各种逻辑器件构成的传输数据的通道；接口是一种连接标准，又常被称为物理接口；协议是数据传输的规则。

PS与PL连接方式主要是通过AXI总线进行的。ZYNQ上的总线协议有AXI4, AXI4-Lite, AXI4-Stream三种总线协议。而PS与PL之间的接口（AXI-GP、AXI-HP、AXI-ACP）只支持AXI4与AXI4-Lite这两种总线协议。

2、**BRAM简介**  
Block RAM是PL部分的存储器阵列，就相当于在PL中开辟一片空间来存储数据，通过端口来进行读写。  
BRAM设置模式：  
1、单端口：通过一个端口对BRAM进行读写。  
2、简单双端口：有两个端口连接到BRAM，一个端口只读，一个端口只写  
3、真双端口：两个端口都可以对BRAM进行读写。

3、**vivado设计**  
**前提：创建好了工程并导入了ZYNQ核**

打开AXI GP0 和 AXI GP1的接口  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 1]

将M\_AXI\_GP0\_ACLK连接到FCLK\_CLK0  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 2]

导入两个BRAM 控制器  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 3]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 4]  
设置为单端口

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 5]

导入一个BRAM  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 6]

设置为真双端口模式

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 7]  
进行设计连接  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 8]  
进行1的时候需要修改主机从GP0 改为GP1  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 9]  
最终的生成图  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 10]  
可以在address editor中查看自动分配的BRAM控制器的地址，不要随意更改地址，因为其他地址可能被其他设备占用了。  
axi\_bram\_ctrl\_0 0x40000000  
axi\_bram\_ctrl\_1 0x80000000

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 11]

接下来生成bit流，将硬件资源导入petlainux中，生成BOOT.BIN 和image.ub

将生成的BOOT.BIN和内核放到板子上，启动系统。

进行编程：

#include <stdio.h>
    #include <unistd.h>
    #include <sys/mman.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    
    #define BRAM_CTRL_0 0x40000000
    #define BRAM_CTRL_1 0x80000000
    #define DATA_LEN    10
    
    int main(int argc, char **argv)
    {
        
        unsigned int *map_base0;
        unsigned int *map_base1;
    
        int fd = open("/dev/mem", O_RDWR | O_SYNC);
        if (fd < 0) {
        
            printf("can not open /dev/mem \n");
            return (-1);
        }   
        printf("/dev/mem is open \n");
    
        map_base0 = mmap(NULL, DATA_LEN * 4, PROT_READ | PROT_WRITE, MAP_SHARED, fd, BRAM_CTRL_0);
        map_base1 = mmap(NULL, DATA_LEN * 4, PROT_READ | PROT_WRITE, MAP_SHARED, fd, BRAM_CTRL_1);
        if (map_base0 == 0 || map_base1 == 0 ) {
         
            printf("NULL pointer\n");
        }   
        else {
        
            printf("mmap successful\n");
        }   
    
        unsigned long addr;
        unsigned int content;
        int i = 0;
    
        printf("\nwrite data to bram\n");
        for (i = 0; i < DATA_LEN; i++) {
        
            addr = (unsigned long)(map_base0 + i); 
            content = i + 2;
            map_base0[i] = content;
            printf("%2dth data, address: 0x%lx data_write: 0x%x\t\t\n", i, addr, content);
    
        }   
    
        printf("\nread data from bram\n");
        for (i = 0; i< DATA_LEN; i++) {
        
            addr = (unsigned long)(map_base1 + i); 
            content = map_base1[i];
            printf("%2dth data, address: 0x%lx data_read: 0x%x\t\t\n", i, addr, content);
        }   
    
        close(fd);
        munmap(map_base0, DATA_LEN);
           munmap(map_base1, DATA_LEN);
    
        return 0;
    }

运行效果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 12]

也可以将BRAM与socket进行联合使用，将PC端的数据发到PS端，PS端放在PL端，PL端再发给PS端，PS端发回PC端。

#include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <errno.h>
    #include <sys/mman.h>
    #include <sys/stat.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <string.h>
    #include <fcntl.h>
    #define PORT 3333
    
    #define BRAM_CTRL0 0x40000000
    #define BRAM_CTRL1 0x80000000
    #define DATA_LEN   100
    
    unsigned int *map_base0;
    unsigned int *map_base1;
    
    
    void udp_server(int sockfd)
    {
        
        
        socklen_t len;
    
        struct sockaddr_in server_addr;
        int n;
        int opt = 1;
    
        
        len = sizeof(server_addr);
        server_addr.sin_family = AF_INET;
        server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
        server_addr.sin_port = htons(PORT);
    
        setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
    
        if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        
            printf("can not bind\n");
            exit(1);
        }   
        
        while (1) {
        
            printf("\n========wait for client's request========\n");
            n = recvfrom(sockfd, map_base0, 1024, 0, (struct sockaddr *)&server_addr, &len);
            char buf[1024];
            memcpy(buf, map_base0, 1024);
            printf("\nreceive client's data: %s\n", buf);
            sendto(sockfd, map_base0, n, 0, (struct sockaddr *)&server_addr, len);
            memcpy(buf, map_base1, 1024);
            printf("\nsend data to client: %s\n", buf);
        }
    
        close(sockfd);
    }
    
    int main(int argc, char **argv)
    {
        
        int sockfd, devfd;
    
        if ((sockfd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
        
            printf("create socket false\n");
            exit(1);
        }
        if ((devfd = open("/dev/mem", O_RDWR | O_SYNC)) < 0) {
        
            printf("can not open /dev/mem \n");
            return (-1);
        }
        printf("\nopen /dev/mem successful\n");
    
        map_base0 = mmap(NULL, DATA_LEN * 4, PROT_READ | PROT_WRITE, MAP_SHARED, devfd, BRAM_CTRL0);
        map_base1 = mmap(NULL, DATA_LEN * 4, PROT_READ | PROT_WRITE, MAP_SHARED, devfd, BRAM_CTRL1);
        if (map_base0 ==0 || map_base1 == 0) {
        
            printf("NULL pointer \n");
        }
        else {
        
            printf("mmap successful\n");
        }
    
        udp_server(sockfd);
    
        exit(0);
    }

最终实现相关效果

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 13]

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 1]: /images/20230528/3072a5e63bef47c9becaadba1d452d72.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvaGUxMg_size_16_color_FFFFFF_t_70 2]: /images/20230528/f5e6c3de10db4ad58c7f6f8d7ebfec65.png
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