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/*
* bbb-gpmc-test
*
* Copyright (C) 2014 Timothy Pearson <kb9vqf@pearsoncomputing.net> (Beaglebone Black)
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
#include <sys/time.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
/** BEGIN: Low-Level I/O Implementation **/
// Beaglebone Black GPMC driver
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#define MEMORY_SPACE_ADDRESS_BITS 15
#define GPMC_BASE 0x50000000
#define GPMC_REGLEN 0x10000000
#define GPMC_CHIPSELECTCONFIGDISPLACEMENT (0x30 / 4)
#define GPMC_CONFIG (0x50 / 4)
#define GPMC_CONFIG1 (0x60 / 4)
#define GPMC_CONFIG2 (0x64 / 4)
#define GPMC_CONFIG3 (0x68 / 4)
#define GPMC_CONFIG4 (0x6c / 4)
#define GPMC_CONFIG5 (0x70 / 4)
#define GPMC_CONFIG6 (0x74 / 4)
#define GPMC_CONFIG7 (0x78 / 4)
#define MEMORY_SIZE (1 << MEMORY_SPACE_ADDRESS_BITS)
int mem_fd = 0;
int gpmc_mem_fd = 0;
char *gpio_mem, *gpio_map, *gpmc_map;
// I/O access
static volatile unsigned int *gpio = NULL;
static volatile unsigned char *gpio_char = NULL;
static volatile unsigned int *gpmc = NULL;
static void gpmc_mapregisters()
{
/* open /dev/mem */
if ((gpmc_mem_fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0) {
printf("can't open /dev/mem \n");
exit (-1);
}
/* mmap GPMC */
gpmc_map = (char *)mmap(
0,
GPMC_REGLEN,
PROT_READ|PROT_WRITE,
MAP_SHARED,
gpmc_mem_fd,
GPMC_BASE
);
if (gpmc_map == MAP_FAILED) {
printf("mmap error %d\n", (int)gpmc_map);
exit (-1);
}
// Always use volatile pointer!
gpmc = (volatile unsigned *)gpmc_map;
}
static void gpmc_unmapregisters()
{
munmap((void*) gpmc, GPMC_REGLEN);
if (gpmc_mem_fd != -1) {
close(gpmc_mem_fd);
}
}
static void gpmc_setup(void)
{
// WARNING: The GPMC runs at the L3 clock frequency!
// It is not well documented, but that frequency seems to be 200MHz on the AM335x series of chips
gpmc_mapregisters();
if (gpmc != NULL) {
int chipselect = 0;
int displacement = GPMC_CHIPSELECTCONFIGDISPLACEMENT * chipselect;
// disable before playing with the registers
*(gpmc + displacement + GPMC_CONFIG7) = 0x00000000;
*(gpmc + displacement + GPMC_CONFIG) = 0x00000000; // Unlimited address space
*(gpmc + displacement + GPMC_CONFIG1) = 0x00000000; // No burst, async, 8-bit, non multiplexed
// // 200MHz compatible SRAM device
// *(gpmc + displacement + GPMC_CONFIG2) = 0x00000800; // Assert CS on fclk 0, deassert CS on fclk 8
// *(gpmc + displacement + GPMC_CONFIG3) = 0x00000200; // Assert ADV on fclk0, deassert ADV on fclk2
// *(gpmc + displacement + GPMC_CONFIG4) = 0x06020802; // Assert WE on fclk2, deassert WE on fclk6, assert OE on fclk2, deassert OE on fclk8
// *(gpmc + displacement + GPMC_CONFIG5) = 0x00060808; // Data valid on fclk 6, cycle time 8 fclks
// 100MHz compatible SRAM device
*(gpmc + displacement + GPMC_CONFIG2) = 0x00001000; // Assert CS on fclk0, deassert CS on fclk16
*(gpmc + displacement + GPMC_CONFIG3) = 0x00000400; // Assert ADV on fclk 0, deassert ADV on fclk 4
*(gpmc + displacement + GPMC_CONFIG4) = 0x0c041004; // Assert WE on fclk4, deassert WE on fclk12, assert OE on fclk4, deassert OE on fclk16
*(gpmc + displacement + GPMC_CONFIG5) = 0x000c1010; // Data valid on fclk 12, cycle time 16 fclks
*(gpmc + displacement + GPMC_CONFIG6) = 0x00000000; // No back to back cycle restrictions
*(gpmc + displacement + GPMC_CONFIG7) = 0x00000e50; // CS0: Set base address 0x10000000, 32MB region, and enable CS
gpmc_unmapregisters();
}
}
static void io_setup(void)
{
printf("sizeof int:\t%d\n", sizeof(int));
/* open /dev/mem */
if ((mem_fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0) {
printf("can't open /dev/mem \n");
exit (-1);
}
/* mmap GPIO */
gpio_map = (char *)mmap(
0,
MEMORY_SIZE,
PROT_READ|PROT_WRITE,
MAP_SHARED,
mem_fd,
0x10000000
);
if (gpio_map == MAP_FAILED) {
printf("mmap error %d\n", (int)gpio_map);
exit (-1);
}
// Always use volatile pointer!
gpio = (volatile unsigned *)gpio_map;
gpio_char = (volatile unsigned char *)gpio_map;
// Select a test from the following blocks of code...
// // DEBUG ONLY
// // Clear out the mapped memory
// int i;
// for (i=0;i<0x3ff; i++) {
// *(gpio + i) = 0x00000000;
// }
// DEBUG ONLY
// Fill the mapped memory with a test pattern
// int j;
// for (j=0;j<0x00001000; j++) {
// *(gpio + j) = j;
// }
// int j;
// for (j=0;j<0x3ff; j++) {
// *(gpio + j) = j;
// }
int j;
for (j=0;j<MEMORY_SIZE; j++) {
*(gpio_char + j) = ((unsigned char)j);
}
// DEBUG ONLY
// Prints the contents of the mapped memory
int k;
for (k=0;k<(MEMORY_SIZE/4); k++) {
printf("0x%08x\t%08x\n", k, *(gpio + k));
}
fflush(stdout);
// // DEBUG ONLY
// // Excercise the memory space
// int l;
// while (1) {
// for (l=0;l<(MEMORY_SIZE/4); l++) {
// k = *(gpio + l);
// }
// }
// while (1) {
// printf("0x%08x\t0x%08x\t0x%08x\t0x%08x\r", *(gpio + 0), *(gpio + 1), *(gpio + 2), *(gpio + 3));
// usleep(1);
// }
// while (1) {
// printf("0x%08x\t0x%08x\t0x%08x\t0x%08x\r", *(gpio + 3), *(gpio + 2), *(gpio + 1), *(gpio + 0));
// usleep(1);
// }
// printf("0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\n\r", *(gpio_char + 0), *(gpio_char + 0), *(gpio_char + 0), *(gpio_char + 0), *(gpio_char + 0), *(gpio_char + 0), *(gpio_char + 0), *(gpio_char + 0));
//
while (1) {
// printf("0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\r", *(gpio_char + 0), *(gpio_char + 1), *(gpio_char + 2), *(gpio_char + 3), *(gpio_char + 4), *(gpio_char + 5), *(gpio_char + 6), *(gpio_char + 7));
// printf("0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\r", *(gpio_char + 0), *(gpio_char + 1), *(gpio_char + 2), *(gpio_char + 3), *(gpio_char + 0x1000), *(gpio_char + 0x1001), *(gpio_char + 0x1002), *(gpio_char + 0x1003));
printf("0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\r", *(gpio_char + 0), *(gpio_char + 1), *(gpio_char + 2), *(gpio_char + 3), *(gpio_char + 0x4000), *(gpio_char + 0x4001), *(gpio_char + 0x4002), *(gpio_char + 0x4003));
// printf("0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\t0x%02x\r", *(gpio_char + 0x4000), *(gpio_char + 0x4001), *(gpio_char + 0x4002), *(gpio_char + 0x4003), *(gpio_char + 0x4000), *(gpio_char + 0x4001), *(gpio_char + 0x4002), *(gpio_char + 0x4003));
usleep(10);
}
}
static void io_shutdown(void)
{
//
}
/** END: Low-Level I/O Implementation **/
int main(int argc, char **argv)
{
gpmc_setup();
printf("GPMC setup complete!\n"); fflush(stdout);
io_setup();
return 0;
}
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