[嵌入式学习] USB设备上电断电应用程序

@allen

转载自  http://www.cubieforums.com/index.php/topic,3753.0.html



有时需要在不拨出设备的情况下，让USB设备不工作或是工作，可以通过映射寄存器后，写高或写低VBUS GPIO，即 the data register of Port H 。

1. #include <stdio.h>
   
2. #include <stdlib.h>
   
3. #include <unistd.h>
   
4. #include <string.h>
   
5. #include <errno.h>
   
6. #include <signal.h>
   
7. #include <fcntl.h>
   
8. #include <ctype.h>
   
9. #include <termios.h>
   
10. #include <sys/types.h>
    
11. #include <sys/mman.h>
    
12. 
    
13. #define MAP_SIZE 4096UL
    
14. #define MAP_MASK (MAP_SIZE - 1)
    
15. 
    
16. int verbose = 0;
    
17. int main(int argc, char **argv)
    
18. {
    
19.   int fd;
    
20.   void *map_base, *virt_addr;
    
21.   unsigned long readval, writeval;
    
22.   off_t porth;
    
23. 
    
24.   if ( argc == 2 && ( argv[1][1] == 'h' || argv[1][1] == '-' ) )
    
25.   {
    
26.     printf("Usage: cbusb [+|-][1|2]...\n");
    
27.     printf("Sets the Cubieboard (A10 and A20) USB power directly for port 1 and 2.\n");
    
28.     printf("USB1 is the upper, USB2 is the lower - closer to the PCB - port.\n\n");
    
29.     printf("Be warned: it directly writes the data register of Port H, bypassing the kernel.\n\n");
    
30.     printf("Without parameters just prints the port power status.\n");
    
31.     printf("+ turns the power on, - turns it off for the specified port.\n");
    
32.     printf("Port H only gets written if the settings differ from the current ones.\n");
    
33.     printf("Note, changing power for one port might momentarily disrupt the other too.\n\n");
    
34.     printf("Examples:\n        cbusb +1\n        cbusb +2 -1\n\n");
    
35.     fflush(stdout);
    
36.   }
    
37. 
    
38.   setuid(0); // try
    
39. 
    
40.   if ( (fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1 )
    
41.   {
    
42.     printf("ERR: Can't open /dev/mem\n");
    
43.     exit(1);
    
44.   }
    
45.   if ( verbose )
    
46.   {
    
47.     printf("/dev/mem opened.\n");
    
48.     fflush(stdout);
    
49.   }
    
50. 
    
51.   porth = 0x1c2090c; // Port H data reg.
    
52. 
    
53.   map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, porth & ~MAP_MASK);
    
54.   if ( map_base == (void *) -1 )
    
55.   {
    
56.     printf("ERR: Can't map the requested memory page\n");
    
57.     exit(2);
    
58.   }
    
59.   if ( verbose )
    
60.   {
    
61.     printf("Memory mapped at address %p.\n", map_base);
    
62.     fflush(stdout);
    
63.   }
    
64. 
    
65.   virt_addr = map_base + (porth & MAP_MASK);
    
66.   readval = *((unsigned long *) virt_addr);
    
67.   printf("USB1: %i\n", (readval & 8) >> 3);
    
68.   printf("USB2: %i\n", (readval & 64) >> 6);
    
69.   if ( verbose ) printf("OLD: 0x%08x\n", readval);
    
70.   fflush(stdout);
    
71. 
    
72.   writeval = readval;
    
73.   int i;
    
74.   for (i=1; i<=2; ++i)
    
75.   {
    
76.     if ( argc > i )
    
77.     {
    
78.       unsigned long usbmask = 0;
    
79.       if ( argv[i][1]=='1' ) usbmask = 8; else if ( argv[i][1]=='2' ) usbmask = 64;
    
80.       if ( argv[i][0]=='+' ) writeval |= usbmask; else writeval &= ~usbmask;
    
81.     }
    
82.   }
    
83.   if ( verbose ) { printf("NEW: 0x%08x\n", writeval); fflush(stdout); }
    
84. 
    
85.   if ( writeval != readval )
    
86.   {
    
87.     *((unsigned long *) virt_addr) = writeval;
    
88.     printf("NEWUSB1: %i\n", (writeval & 8) >> 3);
    
89.     printf("NEWUSB2: %i\n", (writeval & 64) >> 6);
    
90.     fflush(stdout);
    
91.   }
    
92. 
    
93.   if ( munmap(map_base, MAP_SIZE) == -1 )
    
94.   {
    
95.     printf("ERR: munmap failed\n");
    
96.     exit(3);
    
97.   }
    
98. 
    
99.   close(fd);
    
100. 
     
101.   return 0;
     
102. }
     

复制代码

保存为cbusb.c
arm-linux-gnueabihf-gcc-o cbusb cbusb.c
mv cbusb /usr/local/sbin/

查看帮助
cbusb -h

查看状态
cbusb

关闭USB1  
cbusb -1

使能USB1  
cbusb +1

allen

很好，十分感谢。