60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
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/*
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* This test application is to read/write data directly from/to the device
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* from userspace.
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <fcntl.h>
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int main(int argc, char *argv[])
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{
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int fd;
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unsigned long long reg_addr = 0;
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unsigned long long value = 0;
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unsigned long long page_addr, page_offset;
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void *ptr;
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unsigned long long page_size=sysconf(_SC_PAGESIZE);
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printf("REG access through /dev/mem. Page size %llu\n", page_size);
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reg_addr = 0xc8834558;
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/* Open /dev/mem file */
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fd = open ("/dev/mem", O_RDWR);
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if (fd < 1) {
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perror(argv[0]);
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return -1;
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}
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/* mmap the device into memory */
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page_addr = (reg_addr & (~(page_size-1)));
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page_offset = reg_addr - page_addr;
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ptr = mmap(NULL, page_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, page_addr);
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if(ptr < 0){
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printf("mmap failed. see errno for reason.\n");
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close(fd);
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return -1;
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}
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// read 0xC8834558 PREG_ETH1
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value = *((unsigned*)(ptr + page_offset));
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value = value ^ (1<<24);
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value = value ^ (1<<31);
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*((unsigned*)(ptr + page_offset)) = value;
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// read 0xC883455C PREG_ETH1 + 4
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value = *((unsigned*)(ptr + page_offset + 4));
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value = value | (1<<23);
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*((unsigned*)(ptr + page_offset + 4)) = value;
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munmap(ptr, page_size);
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close(fd);
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return 0;
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}
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