rt-thread-official/bsp/loongson/ls1cdev/libraries/ls1c_clock.c

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/*
* Copyright (c) 2006-2018, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2017-09-06 first version
*/
#include "ls1c_regs.h"
#include "ls1c_public.h"
// 晶振的频率
#define AHB_CLK (24000000)
#define APB_CLK (AHB_CLK)
// START_FREQ寄存器bits
#define M_PLL_SHIFT (8)
#define M_PLL (0xff << M_PLL_SHIFT) // PLL倍频系数的整数部分
#define FRAC_N_SHIFT (16)
#define FRAC_N (0xff << FRAC_N_SHIFT) // PLL倍频系数的小数部分
#define DIV_SDRAM_SHIFT (0)
#define DIV_SDRAM (0x3 << DIV_SDRAM_SHIFT)
// CLK_DIV_PARAM寄存器bits
#define DIV_PIX_EN (0x1 << 31)
#define DIV_PIX (0x7f << 24)
#define DIV_CAM_EN (0x1 << 23)
#define DIV_CAM (0x7f << 16)
#define DIV_CPU_EN (0x1 << 15)
#define DIV_CPU (0x7f << 8)
#define DIV_PIX_VALID (0x1 << 5)
#define DIV_PIX_SEL (0x1 << 4)
#define DIV_CAM_VALID (0x1 << 3)
#define DIV_CAM_SEL (0x1 << 2)
#define DIV_CPU_VALID (0x1 << 1)
#define DIV_CPU_SEL (0x1 << 0)
#define DIV_PIX_SHIFT (24)
#define DIV_CAM_SHIFT (16)
#define DIV_CPU_SHIFT (8)
/*
* PLL频率
* @ret PLL频率
*/
unsigned long clk_get_pll_rate(void)
{
unsigned int ctrl;
unsigned long pll_rate = 0;
ctrl = reg_read_32((volatile unsigned int *)LS1C_START_FREQ);
pll_rate = (((ctrl & M_PLL) >> M_PLL_SHIFT) + ((ctrl & FRAC_N) >> FRAC_N_SHIFT)) * APB_CLK / 4;
return pll_rate;
}
/*
* CPU频率
* @ret CPU频率
*/
unsigned long clk_get_cpu_rate(void)
{
unsigned long pll_rate, cpu_rate;
unsigned int ctrl;
pll_rate = clk_get_pll_rate();
ctrl = reg_read_32((volatile unsigned int *)LS1C_CLK_DIV_PARAM);
// 选择时钟来源
if (DIV_CPU_SEL & ctrl) // pll分频作为时钟信号
{
if (DIV_CPU_EN & ctrl)
{
cpu_rate = pll_rate / ((ctrl & DIV_CPU) >> DIV_CPU_SHIFT);
}
else
{
cpu_rate = pll_rate / 2;
}
}
else // bypass模式晶振作为时钟输入
{
cpu_rate = APB_CLK;
}
return cpu_rate;
}
/*
* DDR频率
* @ret DDR频率
*/
unsigned long clk_get_ddr_rate(void)
{
unsigned long cpu_rate = 0;
unsigned long ddr_rate = 0;
unsigned int ctrl;
cpu_rate = clk_get_cpu_rate();
ctrl = reg_read_32((volatile unsigned int *)LS1C_START_FREQ);
ctrl = (ctrl & DIV_SDRAM) >> DIV_SDRAM_SHIFT;
switch (ctrl)
{
case 0:
ddr_rate = cpu_rate / 2;
break;
case 1:
ddr_rate = cpu_rate / 4;
break;
case 2:
case 3:
ddr_rate = cpu_rate / 3;
break;
}
return ddr_rate;
}
/*
* APB频率
* @ret APB频率
*/
unsigned long clk_get_apb_rate(void)
{
return clk_get_ddr_rate();
}
/*
* DC频率
* @ret DC频率
*/
unsigned long clk_get_dc_rate(void)
{
unsigned long pll_rate, dc_rate;
unsigned int ctrl;
pll_rate = clk_get_pll_rate();
ctrl = reg_read_32((volatile unsigned int *)LS1C_CLK_DIV_PARAM);
dc_rate = pll_rate / ((ctrl & DIV_PIX) >> DIV_PIX_SHIFT);
return dc_rate;
}