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gpio.c 1.99 KB
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/*
* Copyright 2024 Hangzhou Yingyi Technology Co., Ltd
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <raspi/gpio.h>
#include <uk/assert.h>
#include <uk/print.h>
#include <uk/ofw/fdt.h>
#include <libfdt.h>
/* Macros to access gpio Registers with base address 'gpio_mem_addr'*/
#define GPIO_REG(r) ((uint32_t *)(gpio_mem_addr + (r)))
#define GPIO_REG_READ(r) ioreg_read32(GPIO_REG(r))
#define GPIO_REG_WRITE(r, v) ioreg_write32(GPIO_REG(r), v)
/*store base address of gpio*/
static uint64_t gpio_mem_addr;
static uint8_t gpio_initialized;
static void wait_cycles(unsigned int n)
{
if (n) {
while (n--)
asm volatile("nop");
}
}
void _libraspiplat_init_gpio(void *fdtp)
{
int gpio_offset, rc;
uint64_t addr, size;
gpio_offset = fdt_node_offset_by_compatible(fdtp, -1,
"brcm,bcm2835-gpio");
if (gpio_offset < 0)
UK_CRASH("No gpio device found!\n");
rc = fdt_get_address(fdtp, gpio_offset, 0, &addr, &size);
if (rc < 0)
UK_CRASH("Could not find gpio address!\n");
gpio_mem_addr = addr;
gpio_initialized = 1;
}
int map_uart_to_gpio(void)
{
if (!gpio_initialized) {
UK_CRASH("GPIO not initialized!\n");
return -1;
}
register uint32_t r;
/* map UART0 to GPIO pins */
r = GPIO_REG_READ(GPFSEL1);
r &= ~((7 << 12) | (7 << 15)); // gpio14, gpio15
r |= (4 << 12) | (4 << 15); // alt0
GPIO_REG_WRITE(GPFSEL1, r);
GPIO_REG_WRITE(GPPUD, 0);
wait_cycles(150);
GPIO_REG_WRITE(GPPUDCLK0, (1 << 14) | (1 << 15));
wait_cycles(150);
GPIO_REG_WRITE(GPPUDCLK0, 0);
return 0;
}
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