[U-Boot-Users] ATA driver in U-Boot

[Wolfgang Denk]

In message <41668573.16343.3D098D at localhost> you wrote:
> 
> Is there any reason that U-Boot needs ATA support compiled in?  I ask because 

No, there is not. Which is the reason that this is an option which is
configurable. And actually most of the boards don't enable it.

> I'm trying to speed up booting on a small system with a hard drive.  U-Boot 
> waits for the devices to become available, scanning the ATA bus, before 
> proceeding to load the Linux kernel.  It appears to me that the kernel then 
> does the same thing again, whereas if it went ahead and went straight to 
> loading the kernel, it would give the drive another second or two to spin up 
> and be ready for a bus scan.

If you enable ATA support in U-Boot you do this because you intend to
use the disk in U-Boot. If this will never be the  case  then  simply
don't enable it. You get what you ask for.

> Given that the kernel is being loaded out of flash (with all drivers compiled 
> in), and that the only reference to the IDE drive that U-Boot really knows 
> about is a commandline parameter passed to the kernel, would it cause any 
> conspicuous problems to remove ATA support from U-Boot, or does the kernel 
> depend on hardware information that U-Boot is providing (I notice there's a 
> "U-Boot" section in the kernel config)?

The kernel does not know which boot loader was running. Just  deiable
ATA support (or anything else) in U-Boot if you don't need it.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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