On Thu, Jun 30, 2011 at 11:54 AM, Raleigh Boulware <r_boulw...@hotmail.com> wrote: > > >> Hi Raleigh, >> >> On Thu, Jun 30, 2011 at 11:16 AM, Raleigh Boulware >> <r_boulw...@hotmail.com> wrote: >> > I have been going through the code and I have stumbled accross a file >> > called >> > sc520_car.S that has something called Cache as ram. I am guessing that >> > this >> > is something special for the sc520 correct? Why was there a need to do >> > this? >> > Why was the Cache used like ram in the boot process? >> >> Cache-As-RAM allows the CPU cache to be used as regular RAM while U-Boot >> is running from Flash before the onboard SDRAM has been initialised. This >> allows a temporary stack, and therefore C runtime environment to be >> created. This this allows you to write the SDRAM initialisation code in C >> which is a lot easier than assembler. >> > So this is pnly used if we want to setup the SDRAM controller in C code
More that just that - It is used for the duration of board_init_f() which may include all manner of peripheral initialisation prior to relocating U-Boot into RAM. > correct? In this code it is not used because the SDRAM cotroller is pretty > much working from power up. So when I port this to my motherboard it looks > as if i really do not need this.. Am I correct in this thinking?? You may need to initialise the SDRAM controller - It really depends on the underlying hardware. You are going to need to have a good look at the technical documentation for your board to figure this one out Regards, Graeme _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
