RE: [PATCH] SDRC: Remove SDRC_POWER register configuration from SDRC init.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



> From: Mike Chan [mailto:mike@xxxxxxxxxxx]
> Sent: Thursday, June 18, 2009 2:01 PM

> > >> Bootloader must configure proper settings for SDRC before starting
> > >> kernel from SDRAM. Furthermore, removed lines violated omap3430 and
> > >> omap2420 SDRC errata (see errata 1.150)
> > >
>
> This seems like it will make the kernel even more dependent on the
> bootloader. As an example, there's code such as the IVA2 reset which
> attempts to put the hardware in a good state even if the bootloader
> screws up. Unfortunately not everyone has access to their bootloader
> code.

Yes, I agree with Mike here.  Not every one can touch the bootloader.  And many operations the boot loader doesn't have context to know what the best setting for an application will be.

The boot loader needs to setup a valid DDR config for sure.  However, its unlikely it will setup for 'optimal' power management.  Further, when there are run time bugs fixes really only the kernel can do this.

You will need to turn on and off autocount before OFF mode on ES3.1.  Not doing so can result in trouble as the mask ROM itself before restoring context to kernel makes a mistake.  There are some SDRC_POWER settings you have to have at run time.

The init code shouldn't through out ACTIMINGS for DDR unless there is some policy in place, but it has less authority around power mode settings.

Regards,
Richard W.
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Arm (vger)]     [ARM Kernel]     [ARM MSM]     [Linux Tegra]     [Linux WPAN Networking]     [Linux Wireless Networking]     [Maemo Users]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Trails]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux