第一种：可以看内核启动信息：
U-Boot 2015.12-rc2 (July 07 2016 - 09:23:56)
Cores: ARM 297 MHz
DDR: 243 MHz
I2C: ready
DRAM: 128 MiB
NAND: 512 MiB
MMC: davinci: 0, davinci: 1
Bad block table found at page 262080, version 0x01
Bad block table found at page 262016, version 0x01
Net: Ethernet PHY: LXT972 @ 0x01
DaVinci-EMAC
Hit any key to stop autoboot: 0
第二种：执行：cat /proc/davinci_clocks，查看 arm_clk 的值。
root@dm368-evm:/proc# cat davinci_clocks
ref_clk users=1624000000 Hz
pll1users=15 pll 486000000 Hz
pll1_aux_clk users= 5 pll 24000000 Hz
uart0 users= 1 psc 24000000 Hz
i2c users= 1 psc 24000000 Hz
spi4 users= 0 psc 24000000 Hz
pwm0 users= 0 psc 24000000 Hz
pwm1 users= 0 psc 24000000 Hz
pwm2 users= 0 psc 24000000 Hz
timer0users= 1 psc 24000000 Hz
timer1users= 0 psc 24000000 Hz
timer2users= 2 psc 24000000 Hz
timer3users= 0 psc 24000000 Hz
usb users= 1 psc 24000000 Hz
pll1_sysclkbp users= 0 pll 24000000 Hz
clkout0 users= 0 pll 24000000 Hz
pll1_sysclk1 users= 0 pll 24300000 Hz
pll1_sysclk2 users= 0 pll 243000000 Hz
pll1_sysclk3 users= 2 pll 243000000 Hz
vpss_dac users= 1 psc 243000000 Hz
mjcp users= 1 psc 243000000 Hz
pll1_sysclk4 users= 6 pll 121500000 Hz
uart1 users= 1 psc 121500000 Hz
mmcsd1users= 0 psc 121500000 Hz
spi0 users= 0 psc 121500000 Hz
spi1 users= 0 psc 121500000 Hz
spi2 users= 0 psc 121500000 Hz
spi3 users= 0 psc 121500000 Hz
gpio users= 1 psc 121500000 Hz
aemif users= 2 psc 121500000 Hz
emac users= 1 psc 121500000 Hz
asp0 users= 1 psc 121500000 Hz
rto users= 0 psc 121500000 Hz
pll1_sysclk5 users= 1 pll 243000000 Hz
vpss_master users= 1 psc 243000000 Hz
pll1_sysclk6 users= 0 pll 27000000 Hz
pll1_sysclk7 users= 0 pll 486000000 Hz
pll1_sysclk8 users= 1 pll 97200000 Hz
mmcsd0users= 1 psc 97200000 Hz
pll1_sysclk9 users= 0 pll 243000000 Hz
pll2users= 1 pll 594000000 Hz
pll2_aux_clk users= 0 pll 24000000 Hz
clkout1 users= 0 pll 24000000 Hz
pll2_sysclk1 users= 0 pll 23760000 Hz
pll2_sysclk2 users= 1 pll 297000000 Hz
arm_clk users= 1 psc 297000000 Hz
pll2_sysclk3 users= 0 pll 297000000 Hz
pll2_sysclk4 users= 0 pll 20482758 Hz
voice_codec users= 0 psc 20482758 Hz
pll2_sysclk5 users= 0 pll 74250000 Hz
pll2_sysclk6 users= 0 pll 594000000 Hz
pll2_sysclk7 users= 0 pll 594000000 Hz
pll2_sysclk8 users= 0 pll 594000000 Hz
pll2_sysclk9 users= 0 pll 594000000 Hz
pwm3users= 0 psc 24000000 Hz