dvfs一共有3处
cpu，gpu，ddr
cpu和gpu都是默认开启的
ddr dvfs代码还没有进行合并,现在是一直工作在533mhz
CPU
cpu，gpu的频点在rk3288.dtsi修改,电压在vdd_cpu上，
如果测试有相应问题，可以先尝试修改这些频点
cpu0: cpu@500 {
device_type = "cpu";
compatible = "arm,cortex-a12";
reg = <0x500>;
resets = <&cru SRST_CORE0>;
operating-points = <
/* KHz uV */
1608000 1350000
1512000 1300000
1416000 1200000
1200000 1100000
1008000 1050000
816000 1000000
696000 950000
600000 900000
408000 900000
312000 900000
216000 900000
126000 900000
>;
#cooling-cells = <2>; /* min followed by max */
clock-latency = <40000>;
clocks = <&cru ARMCLK>;
};
&cpu0 {
cpu0-supply = <&vdd_cpu>;
};
GPU
电压在vdd_gpu
gpu: gpu@ffa30000 {
compatible = "arm,malit764",
"arm,malit76x",
"arm,malit7xx",
"arm,mali-midgard";
reg = <0xffa30000 0x10000>;
interrupts = <GIC_SPI 6 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>;
interrupt-names = "JOB", "MMU", "GPU";
clocks = <&cru ACLK_GPU>;
clock-names = "clk_mali";
operating-points = <
/* KHz uV */
600000 1250000
/* 500000 1200000 - See crosbug.com/p/33857 */
400000 1100000
300000 1000000
200000 950000
100000 950000
>;
#cooling-cells = <2>; /* min followed by max */
power-domains = <&power RK3288_PD_GPU>;
status = "disabled";
};
&gpu {
mali-supply = <&vdd_gpu>;
status = "okay";
};
DDR
ddr上的变频因为没有硬件支持，实现比较trick，变频代码存在sram中
需要注意的是变频的操作是在vblank的时候进行的，如果vblank不满足要求，不会开启变频
下面的patch里已经打开了debug log，所以可以通过看dmc的log看看是不是没满足要求
drivers/gpu/drm/rockchip/rockchip_drm_vop.c
#ifdef CONFIG_ARM_RK3288_DMC_DEVFREQ
u64 vblank_time;
/*
* Make sure we disable _before_ changing the mode / disabling the
* clock since we need the mode to be right during the disable.
*/
vblank_time = adjusted_mode->vtotal - adjusted_mode->vdisplay;
vblank_time *= (u64)NSEC_PER_SEC * adjusted_mode->htotal;
do_div(vblank_time,
clk_round_rate(vop->dclk, adjusted_mode->clock * 1000));
if (vblank_time <= DMC_SET_RATE_TIME_NS + DMC_PAUSE_CPU_TIME_NS) {
/*
* Set a large timeout so we can change the clk rate to max when
* dmc freq is disabled.
*/
rockchip_dmc_lock();
vop->vblank_time = DMC_DEFAULT_TIMEOUT_NS;
rockchip_dmc_unlock();
if (!vop->dmc_disabled_rk3288)
rockchip_dmc_disable();
vop->dmc_disabled_rk3288 = true;
}
#endif
patches: (可以checkout这个branch，然后cherry-pick对应的commit）
https://github.com/rockchip-linux/kernel/commits/release-20160920-miniarm-dev
从rockchip: dmc: copy dmc driver from 3.14到MINIARM: dmc work
一些操作
查看cpu可用频点
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
设置cpu最高频率
echo 216000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
设置cpu最低频率
echo 216000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
更多详细信息（cpu变频策略，使用率）：
cpufreq-info
设置策略
cpufreq-set
gpu 当前频率
cat /sys/devices/platform/ffa30000.gpu/devfreq/ffa30000.gpu/cur_freq
gpu 可以用的变频策略
cat /sys/devices/platform/ffa30000.gpu/devfreq/ffa30000.gpu/available_governors
设置变频策略
/sys/devices/platform/ffa30000.gpu/devfreq/ffa30000.gpu/governors
查看ddr频率
cat /sys/kernel/debug/clk/clk_summary | grep dpll_ddr
查看ddr log
log已经打开，每次变频都会有输出
--测试
所有dvfs全打开的情况下
cpu：
来回stresstest
ddr：
while true
do
killall memtester
memtester 1G 1
sleep $RANDOM%300
done
一般cpu上的异常或者频率电压不匹配会造成随机的kernel panic，
ddr上的异常会死机，另外频率和电压不匹配会有随机的内部clk异常
su linaro -c "DISPLAY=:0.0 glmark2-es2 —benchmark refract —run-forever —off-screen"
while true; do cat /sys/class/thermal/thermal_zone1/temp; sleep 1; done &
while true; do cat /sys/class/thermal/thermal_zone2/temp; sleep 1; done &
while true; do cat /sys/devices/platform/ffa30000.gpu/devfreq/ffa30000.gpu/cur_freq; sleep 1; done &
cpu频率
md5sum /dev/zero
stress —cpu 6 —io 4 —vm 2 —vm-bytes 128M —timeout 1000
升gpu频率
su linaro -c "DISPLAY=:0.0 glmark2-es2 —benchmark refract —run-forever —off-screen"
cpu gpu温度
while true; do cat /sys/class/thermal/thermal_zone1/temp; sleep 1; done &
while true; do cat /sys/class/thermal/thermal_zone2/temp; sleep 1; done &
gpu频率
while true; do cat /sys/devices/platform/ffa30000.gpu/devfreq/ffa30000.gpu/cur_freq; sleep 1; done &
cpu频率
/sys/devices/system/cpu/cpu0/cpufreq/xxx
vlc 测试视频
su lianro -c "DISPLAY=:0.0 vlc 视频“
