rt-thread-official/bsp/allwinner_tina/libcpu/rt_low_level_init.c

/*
 * Copyright (c) 2006-2021, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2018-02-08     RT-Thread    the first version
 */

void rt_low_level_init(void)
{
    volatile unsigned int *addr;
    volatile unsigned int time;
    int i;

    //change cpu clk source to 24M
    addr = (unsigned int *)(0x01c20000 + 0x050);
    *addr = 0x10000;
    //init cpu pll clk 408M
    addr = (unsigned int *)(0x01c20000 + 0x000);
    *addr = 0x80001000;
    time = 0xffff;
    while ((!(*addr & (0x1 << 28))) && (time--));
    //change cpu clk source to pll
    if (time > 0)
    {
        addr = (unsigned int *)(0x01c20000 + 0x050);
        *addr = 0x20000;
    }

    //init periph pll clk:600M
    //init ahb    pll clk:200M
    //init apb    pll clk:100M
    addr = (unsigned int *)(0x01c20000 + 0x028);
    if (*addr & (0x1 << 31))
        return;

    addr = (unsigned int *)(0x01c20000 + 0x200);
    *addr = 0x1ff;
    addr = (unsigned int *)(0x01c20000 + 0x204);
    *addr = 0x1ff;

    addr = (unsigned int *)(0x01c20000 + 0x028);
    *addr |= (0x1 << 31);
    while (!(*addr & (0x1 << 28)));

    addr = (unsigned int *)(0x01c20000 + 0x054);
    *addr = (0x0 << 16) | (0x3 << 12) | (0x0 << 8) | (0x2 << 6) | (0x0 << 4);

    //init gpio config
    for (i = 0; i < 6; i++)
    {
        if (i == 1)
            continue;// not config gpio B

        addr = (unsigned int *)(0x01c20800 + i * 0x24 + 0x00);
        *addr = 0x77777777;
        addr = (unsigned int *)(0x01c20800 + i * 0x24 + 0x04);
        *addr = 0x77777777;
        addr = (unsigned int *)(0x01c20800 + i * 0x24 + 0x08);
        *addr = 0x77777777;
        addr = (unsigned int *)(0x01c20800 + i * 0x24 + 0x0C);
        *addr = 0x77777777;
    }
}