topic Re: HBus autoslow feature in i.MX Processors

HBus autoslow feature

lategoodbye — Fri, 26 Jun 2015 05:58:17 GMT

Hi,

i've compared Linux busfreq driver in FSL BSP between mx23 and mx28 . In the mx23 profile the h_autoslow_flags are greater 0, but in the mx28 profile they are always 0 (=unused from my understanding).

What's the reason for this?

Best regards

Stefan Wahren

Re: HBus autoslow feature

Yuri — Mon, 29 Jun 2015 05:51:12 GMT

Linux BSP for i.MX28 supports standard CPUFREQ feature in order
to configure several typical configurations for CPU and memory / bus
frequencies.

Have a great day,
Yuri

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Re: HBus autoslow feature

lategoodbye — Mon, 29 Jun 2015 06:53:34 GMT

Hi Yuri,

let me clarify my question:

Why doesn't the mx28 busfreq driver make use of HBus autoslow feature?

Are there any drawbacks that leads to that descision?

Re: HBus autoslow feature

Yuri — Mon, 29 Jun 2015 10:04:23 GMT

We do not use the hardware auto-slow mode for the HBUS
(HW_CLKCTRL_HBUS[AUTO_SLOW_MODE] = 1).
Software (manual) approach is used instead. This allows
to re-configure correctly memory frequency too.

Regards,
Yuri.