topic Re: Local bus pll enable in P-Series

P2020 Local bus pll enable

wangxiao — Fri, 30 Jun 2017 09:37:01 GMT

Hi,

I met the problem.Platform clock is 400MHz,i want to set local bus clock for 100MHz,so add in the .h file:

#define CONFIG_SYS_LBC_LCRR 0x00030002 /* local bus freq */

bit 0 PLL enable

clock divide 4

Clock ratio register (eLBC_LCRR) bit 0 PBYP should be 0,means the PLL enable.

After set the register， I read this register data is 0x80030002,bit 0 still 1 in bypass mode ,is that right?

（Additionally，Bypass mode ,local bus cycle time minnum 12ns，so the clock maxmum 83MHz）

ufedor — Fri, 30 Jun 2017 10:27:05 GMT

Which processor is in question?

wangxiao — Mon, 03 Jul 2017 05:34:57 GMT

P2020

ufedor — Mon, 03 Jul 2017 05:38:42 GMT

Please use debugger to debug U-Boot.

wangxiao — Mon, 03 Jul 2017 08:33:25 GMT

Thanks。

Progam：

clrsetbits_be32(&lbc->lcrr, LCRR_CLKDIV, CONFIG_SYS_LBC_LCRR);

__raw_readl(&lbc->lcrr);
isync();

the reason:

clrsetbits_be32(&lbc->lcrr, LCRR_CLKDIV, CONFIG_SYS_LBC_LCRR) mapping to

out_be32(&lbc->lcrr,inbe32(&lbc->lcrr) & (~LCRR_CLKDIV) | CONFIG_SYS_LBC_LCRR)

actually it does not change bit 0

solution:

*(volatile *)(&lbc->lcrr) = CONFIG_SYS_LBC_LCRR ;

then it‘s ok