Zynq Linux axi lite实验
本实验目的是模拟ps端给pl端发参数控制pl端运行的情况，实际使用的是led闪烁来演示
项目地址：http://120.55.75.228:23080/zhdyz/axi_lite_linux
实验目的
linux端通过命令行控制pl端led灯的闪烁频率和参数可修改时间，在这端时间内参数会进入锁定状态，直到这段时间后才会读入下一批写入的参数
实验流程
报错记录
Vivado报错
Spawn failed：No error
原因分析：字面意思，没有错误，但软件硬是要报错，忽略即可
Linking the ceam library to the veamMap failed. Most likely, you need to check your installation or recompile your sandbox.
原因分析：程序综合时内存空间不足，关闭电脑打开的其他程序，清理内存空间后重新运行Vivado
Vitis平台工程编译出错
原因分析：之前有篇文章讲过这个问题，但有段时间没使用axi lite了，忘记了使用 自定义axi ip核时官方自动创建的Makefile有问题，需要修改
参考：https://www.limfx.pro/ReadArticle/3646/vitis-bian-cheng-tou-wen-jian-xparametersh-wu-fa-zhao-dao
Vivado部分
实现led闪烁和参数锁存的是led_ctrl模块，代码如下
module led_ctrl(
input wire clk,
input wire rstn,
input wire [15:0] led_freq,
input wire [15:0] led_second,
output reg led,
output reg idle// 0表示空闲，1表示正在工作
);
reg [31:0]sec_cnt;
reg [15:0]freq;
reg [15:0]second;
reg [15:0] locked_freq;
reg [15:0] locked_second;
//锁存freq和second
always@(posedge clk) begin
if(rstn==1'b0) begin
freq<=0;
second<=0;
end
else if(idle==1'b0) begin
freq<=led_freq;
second<=led_second;
locked_freq<=led_freq;
locked_second<=led_second;
end
else begin
freq<=locked_freq;
second<=locked_second;
end
end
//分频出四个时钟
reg clk1,clk2,clk3,clk4;
//idle状态控制
always@(posedge clk3) begin
if(rstn==1'b0) begin
idle<=1'b0;
sec_cnt<=0;
end
//idle
if(idle==1'b0) begin
if(freq>0) idle<=1'b1;
end
//working
else begin
if(sec_cnt==second-1) begin
idle<=1'b0;
sec_cnt<=0;
end
else
sec_cnt<=sec_cnt+1;
end
end
reg [31:0]cnt4;
//clk4 = 2HZ
always@(posedge clk) begin
if(rstn==1'b0) begin
clk4<=0;
cnt4<=0;
end
else begin
if(cnt4==24999999) begin
cnt4<=0;
clk4<=~clk4;
end
else cnt4<=cnt4+1;
end
end
//clk3 = 1HZ
always@(posedge clk4) begin
if(rstn==1'b0)
clk3<=0;
else
clk3<=~clk3;
end
//clk2 = 0.5HZ
always@(posedge clk3) begin
if(rstn==1'b0)
clk2<=0;
else
clk2<=~clk2;
end
//clk1 = 0.25HZ
always@(posedge clk2) begin
if(rstn==1'b0)
clk1<=0;
else
clk1<=~clk1;
end
always@(posedge clk) begin
if(rstn==1'b0)
led=1'b0;
else if(idle==1'b0)
led=1'b0;
else begin
if(freq==1) begin
if(clk1==1) led=1'b1;
else led=1'b0;
end
else if(freq==2) begin
if(clk2==1) led=1'b1;
else led=1'b0;
end
else if(freq==4) begin
if(clk3==1) led=1'b1;
else led=1'b0;
end
else if(freq==8) begin
if(clk4==1) led=1'b1;
else led=1'b0;
end
end
end
endmodule
这个模块是关键，其输入的参数freq和second是从axi lite ip核中引出的，整体的block design图如下图所示，引出的led和idle引脚分别对应开发板上的两个pl端led灯
block design设计好后，生成Bitstream，导出xsa
Vitis设计部分
导入xsa，创建平台工程，获得开机启动文件和设备树文件，设备树代码如下
可以看到pl端设备树代码主要就是描述了axi lite ip核的设备信息
/ {
amba_pl: amba_pl@0 {
#address-cells = <2>;
#size-cells = <2>;
compatible = "simple-bus";
ranges ;
axi_lite_led_0: axi_lite_led@80000000 {
/* This is a place holder node for a custom IP, user may need to update the entries */
clock-names = "s00_axi_aclk";
clocks = <&zynqmp_clk 71>;
compatible = "xlnx,axi-lite-led-1.0";
reg = <0x0 0x80000000 0x0 0x10000>;
xlnx,s00-axi-addr-width = <0x4>;
xlnx,s00-axi-data-width = <0x20>;
};
};
};
然后将这些文件传输到虚拟机，交叉编译成BOOT文件，放至SD卡，硬件部分就准备好了
驱动编写
驱动代码axi_led_drv.c如下，其中的AxiUserGpio_write函数的功能是接收app写的数据，然后通过axi lite传输到pl端
#include <linux/ide.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/delay.h>
struct AxiUserGpio
{
int addr_width;
int data_width;
struct device_node *dev_node;
int reg_num;
unsigned int *reg_value;
};
struct AxiUserGpio *AxiUserGpio_data;
static int key_major;
static struct class *key_cls;
static unsigned int *AxiData_0 = NULL;
//注意这里.compatible的字符串和pl.dtsi中的属性是相对应的
static struct of_device_id AxiUserGpio_of_match[] = {
{.compatible = "xlnx,axi-lite-led-1.0"},
{},
};
int of_AxiUserGpio_data(struct AxiUserGpio *pdata, struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
int ret = 0;
pdata->reg_num = of_property_count_elems_of_size(np, "reg", sizeof(int));
if (pdata->reg_num < 0)
{
dev_err(&pdev->dev, "get reg_num failed\n");
return ret;
}
pdata->reg_value = (unsigned int *)kmalloc(sizeof(unsigned int) * pdata->reg_num, GFP_KERNEL);
if (!pdata->reg_value)
{
kfree(pdata->reg_value);
dev_err(&pdev->dev, "kmalloc failed\n");
return -1;
}
ret = of_property_read_u32_array(np, "reg", pdata->reg_value, pdata->reg_num);
if (ret != 0)
{
kfree(pdata->reg_value);
dev_err(&pdev->dev, "get reg failed\n");
return ret;
}
ret = of_property_read_u32(np, "xlnx,s00-axi-addr-width", &pdata->addr_width);
if (ret < 0)
{
dev_err(&pdev->dev, "get addr_width failed\n");
return ret;
}
ret = of_property_read_u32(np, "xlnx,s00-axi-data-width", &pdata->data_width);
if (ret < 0)
{
dev_err(&pdev->dev, "get data_width failed\n");
return ret;
}
return 0;
}
static int AxiUserGpio_probe(struct platform_device *pdev)
{
int ret = 0;
int i = 0;
struct device *dev = &pdev->dev;
struct AxiUserGpio *pdata = dev_get_platdata(dev);
if (!pdata)
{
pdata = devm_kzalloc(dev, sizeof(struct AxiUserGpio), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
platform_set_drvdata(pdev, pdata);
}
ret = of_AxiUserGpio_data(pdata, pdev);
AxiUserGpio_data = pdata;
// 打印属性值
printk("addr_width = %d\r\n", AxiUserGpio_data->addr_width);
printk("data_width = %d\r\n", AxiUserGpio_data->data_width);
printk("reg_num = %d\r\n", AxiUserGpio_data->reg_num);
for (i = 0; i < AxiUserGpio_data->reg_num; i += 2)
{
printk("reg = %#X %#X \r\n", AxiUserGpio_data->reg_value[i], AxiUserGpio_data->reg_value[i + 1]);
}
AxiData_0 = ioremap(AxiUserGpio_data->reg_value[1] + AxiUserGpio_data->addr_width * 0, AxiUserGpio_data->addr_width);
return ret;
}
static int AxiUserGpio_remove(struct platform_device *pdev)
{
kfree(AxiUserGpio_data->reg_value);
iounmap(AxiData_0);
return 0;
}
int AxiUserGpio_open(struct inode *inode, struct file *filp)
{
printk("axi gpio open\n");
return 0;
}
ssize_t AxiUserGpio_write(struct file *filp, const char __user *buf, size_t count, loff_t *fops) //用户发送，内核读取信息并打印
{
int flag = 0;
int a[2]={0}; //a[0]=second , a[1]=freqence
flag = copy_from_user(a, buf, count); //使用copy_from_user读取用户态发送过来的数据
int write_data=0;
write_data=(a[1]<<16)+a[0];//freq = high 12 bits , second = middle 12 bits , idle = low 8 bits
if (flag == 0)
{
printk(KERN_CRIT "Kernel receive data: %d\n", write_data);
}
else
{
printk("Kernel receive data failed!\n");
}
writel(write_data, AxiData_0);
printk("-led write-\n");
return 0;
}
int AxiUserGpio_close(struct inode *inode, struct file *filp)
{
printk("axi gpio close\n");
return 0;
}
const struct file_operations key_fops = {
.open = AxiUserGpio_open,
.write = AxiUserGpio_write,
.release = AxiUserGpio_close,
};
static struct platform_driver AxiUserGpio_device_driver = {
.driver = {
.name = "AxiUserGpio",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(AxiUserGpio_of_match),
},
.probe = AxiUserGpio_probe,
.remove = AxiUserGpio_remove,
};
static int __init AxiUserGpio_init(void)
{
key_major = register_chrdev(0, "axi_gpio_led", &key_fops);
if (key_major < 0)
{
printk("register chrdev faile!\n");
return key_major;
}
printk("register chrdev ok!\n");
key_cls = class_create(THIS_MODULE, "key_class");
printk("class create ok!\n");
device_create(key_cls, NULL, MKDEV(key_major, 0), NULL, "gpio_led%d", 0);
printk("device create ok!\n");
return platform_driver_register(&AxiUserGpio_device_driver);
}
static void __exit AxiUserGpio_exit(void)
{
device_destroy(key_cls, MKDEV(key_major, 0));
//删除类
class_destroy(key_cls);
//注销主设备号
unregister_chrdev(key_major, "axi_gpio_led");
platform_driver_unregister(&AxiUserGpio_device_driver);
}
late_initcall(AxiUserGpio_init);
module_exit(AxiUserGpio_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("uisrc");
应用编写
axi_led_app.c
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
int fd = 0;
int retvalue = 0;
int i = 0;
int a[2] = {0};
fd = open("/dev/gpio_led0", O_RDWR);
if (fd < 0)
{
perror("open fail!\n");
exit(1);
}
if (argc != 3) //进行鲁棒性检查
{
printf("Unknow operation, use the formate: ./APPNAME WRITE_TIME WRITE_FREQUENCE to write date to kernel.\n");
return -2;
}
a[0]=atoi(argv[1]);
a[1]=atoi(argv[2]);
retvalue = write(fd, a, sizeof(a)); //写数据
if (retvalue < 0)
{
printf("Write led failed!\n");
}
else
{
printf("Write led success!\n");
}
close(fd);
return 0;
}
实验结果
应用程序写好后，使用的命令格式为
./axi_led_app second freq
其中second的取值为正整数，单位是秒，通常取5,10,20即可；
freq的取值为1,2,4,8，分别代表0.25Hz，0.5Hz，1Hz，2Hz频率
如
./axi_led_app 10 1
./axi_led_app 10 8
./axi_led_app 5 2
就分别表示以0.25Hz运行，10s内锁存参数；以2Hz运行，10s内锁存参数；以0.5Hz运行，5s内锁存参数
连续输入以下命令
./axi_led_app 10 1
./axi_led_app 10 4
./axi_led_app 10 8
那会先以0.25Hz闪烁10s，然后以2Hz一直闪烁
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