Re: serial Flash over SPI as rootdevice?

[Alexander Stein <alexander.stein@systec-electronic.com>]

Hello Thomas,

On Tuesday 09 April 2013 10:21:26, Thomas.Betker@rohde-schwarz.com wrote:
> Hello Alexander:
> 
> > is it currently possible to use a serial Flash connected over SPI to
> > use as a rootdevice?
> > If not, would it be possible and which drivers need to be written 
> > for that then?
> 
> Yes, it is certainly possible; we are doing it ourselves. No extra drivers 
> are required for this beyond those you need anyway (SPI driver, SPI flash 
> driver).

That sound great. Could you please point me to the driver needed for that? Do you have any performance comparisons to e.g. NOR flash?

> The real problem, though, is that you cannot boot from standard SPI flash. 
> For this, you need memory which can be read directly by the CPU, such as 
> parallel NOR flash.

Well, the idea is to use an AT91 which can boot directly from serial flash with it's own ROM code. This would load the bootloader (will be u-boot likely) which in turns needs to fetch the kernel from the serial flash too. Should be possible, no?

Best regards,
Alexander