D1-h裸机下修改主频无效

[LiuQingchang]

static void set_pll_cpux_axi(void)
{
	uint32_t val;

	/* Select cpux clock src to osc24m, axi divide ratio is 3, system apb clk ratio is 4 */
	//切换CPU时钟源
	write32(D1_CCU_BASE + CCU_RISCV_CLK_REG, (0 << 24) | (3 << 8) | (1 << 0));
	sdelay(1);

	/* Disable pll gating */
	//关PLL输出门
	val = read32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG);
	val &= ~(1 << 27);
	write32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG, val);

	/* Enable pll ldo */
	//使能PLL_LDO
	val = read32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG);
	val |= (1 << 30);
	write32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG, val);
	sdelay(5);

	/* Set default clk to 1008mhz */
	//配置PLL_CPU倍频系数
	val = read32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG);
	val &= ~((0x3 << 16) | (0xff << 8) | (0x3 << 0));
	val |= (41 << 8);
	write32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG, val);

	/* Lock enable */
	//PLL锁使能
	val = read32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG);
	val |= (1 << 29);
	write32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG, val);

	/* Enable pll */
	//使能PLL
	val = read32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG);
	val |= (1 << 31);
	write32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG, val);

	/* Wait pll stable */
	//等待PLL稳定
	while(!(read32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG) & (0x1 << 28)));
	sdelay(20);

	/* Enable pll gating */
	//使能PLL输出门
	val = read32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG);
	val |= (1 << 27);
	write32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG, val);

	/* Lock disable */
	//关PLL锁
	val = read32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG);
	val &= ~(1 << 29);
	write32(D1_CCU_BASE + CCU_PLL_CPU_CTRL_REG, val);
	sdelay(1);

	/* Set and change cpu clk src */
	//切换时钟源为PLL_CPU
	val = read32(D1_CCU_BASE + CCU_RISCV_CLK_REG);
	val &= ~(0x07 << 24 | 0x3 << 8 | 0xf << 0);
	val |= (0x05 << 24 | 0x1 << 8);
	write32(D1_CCU_BASE + CCU_RISCV_CLK_REG, val);
	sdelay(1);
}

这是我的修改主频函数

    while(1) {
        for (volatile uint32_t k = 0; k < 3000000; k++) {
            __asm__("nop");
        }
        gpio_reverse(LIGHT_BLUE);        

    }

这是测试函数，利用小灯翻转速度直观的。

★ CPU 频率测试程序 (LED + mcycle) ★
RISCV_CLK_REG = 0x05000100
PLL_CPU_CTRL = 0xCA002900
CPU_AXI_CFG_REG = 0x00000300

我在执行循环前打印出了三个寄存器内容，如上，内容修改成功，但是主频很低，大概3MHz，不管怎么修改寄存器内容或者修改时钟源都不行，都很低。
有什么懂D1裸机主频配置流程的大佬指点一下，是否忽略了什么配置，谢谢。

[awwwwa]

主频很低，大概3MHz 是GPIO翻转的主频吗？
核心最低主频是24MHz，不可能低到3M的

D1-H 的 GPIO 是通过 APB 连到 CPU 的，其运行速率与CPU不是同步的

[LiuQingchang]

@awwwwa 我是这样计算的。开一个毫秒定时器

            TMR0_CTRL_REG &=~(0xFF<<0);  //reset
            TMR0_CTRL_REG &=~(0x1<<7);   //Periodic mode
            TMR0_CTRL_REG |=((0x6<<4)|(0x1<<2));    //64 pre-scale,OSC24M
            TMR0_INTV_VALUE_REG=(uint32_t)(375*time_ms);
            TMR0_CTRL_REG |=(0x1<<1);    //Reload
            TMR0_CTRL_REG |=(0x1<<0);    //start

然后在while循环中两秒计算进行了多少次时钟。

        min = gTime[1];
        while(gTime[1]-min <=2)
        {
            min64++;
            __asm__("nop");
        }
        printf("1 秒内 mcycle 增加  cycles=");
        print_uint64(min64);
        printf("CPU 实际主频 ≈ %d MHz\n", min64 / 2000000ULL);
        min64 = 0;

最后根据计数算出来的主频就在3M左右，很低，我怀疑时钟寄存器有什么地方忽略了什么配置。

[LiuQingchang]

@awwwwa

        for (volatile uint32_t k = 0; k < 3000000; k++) {
            __asm__("nop");
        }
        gpio_reverse(LIGHT_BLUE);     

这个是每3,000,000个时钟信号，翻转一次小灯，我看小灯也就大概一秒多一点翻转一次，可以推测主频就3M左右。

[LiuQingchang]

@awwwwa 您有什么方法可以用示波器测量输出频率吗？

[awwwwa]

@liuqingchang cpu主频一般不采用外设测量，一般是看寄存器和coremark综合评估

[bacteria]

@liuqingchang Should you even write anything to CPU_AXI_CFG_REG?
I thought this register is for the ARM core, which is not present in D1, but is present in the base design from which D1 and T113 are derived.

[bacteria]

CPU_AXI_CFG_REG is not active on D1?
It's for ARM core which is present in the original silicon design from D1 and T113 are derived?