Armada XP Internal registers

[Jason Cooper]

Hi Matthew,

On Mon, Oct 21, 2013 at 02:43:40PM -0300, Ezequiel Garcia wrote:
> On Mon, Oct 21, 2013 at 03:47:43PM +0100, Matthew Minter wrote:
> > I recently had to upgrade the boot loader on my Armada XP GP board (as
> > I could not get the sources for the old version, only the binaries for
> > the SPI flash version and needed to build a bootloader to boot from
> > NAND flash).
> > 
> > After upgrading I experienced a number of problems on both the mvebu tree and
> > Ezequiel Garcia's v2 NAND develoment tree (here
> > https://github.com/MISL-EBU-System-SW/mainline-public/tree/l2-mtd/upstream-nand-v2)
> > (which otherwise runs really well, so thanks)
> > 
> > However I do not think it is the fault of either kernel. Specifically
> > it seems the new bootloader is sticking the internal registers at
> > 0xf1000000 instead of 0xd0000000. Specifically this was causing the
> > kernel to oops and then panic when trying to init the IRQ or serial
> > uart.
> > 
> > It seems that changing the armada-xp-gp device tree to read:
> >         soc {
> >                 ranges = <MBUS_ID(0xf0, 0x01) 0 0 0xf1000000 0x100000
> >                           MBUS_ID(0x01, 0x1d) 0 0 0xfff00000 0x100000
> >                           MBUS_ID(0x01, 0x2f) 0 0 0xf0000000 0x1000000>;
> > 
> > 
> > instead of:
> >         soc {
> >                 ranges = <MBUS_ID(0xf0, 0x01) 0 0 0xd0000000 0x100000
> >                           MBUS_ID(0x01, 0x1d) 0 0 0xfff00000 0x100000
> >                           MBUS_ID(0x01, 0x2f) 0 0 0xf0000000 0x1000000>;
> > 
> > causes the chip to get further in boot, however at this point I found
> > another issue. The kernel was experiencing another oops (which was
> > killing either init or the idle process) due to an error "Unhandled
> > fault: external abort on non-linefetch (0x808) at 0xf0144010"
> > 
> > I again managed to get past this by not configuring the serial port on
> > the kernel command line however this has the significant drawback that
> > I do not get any messages from the kernel or my init system over
> > serial and the terminal remains blank until a getty eventually spawns.
> > This makes other boot issues hard to debug.
> > 
> > I am not completely sure if this is a boot-loader issue, a kernel
> > issue or my own misconfiguration. However I can make the chip boot so
> > it is not too urgent, just introduces annoying limitations.
> > 
> > If anyone has any ideas on this I would be very grateful, best regards,
> 
> Hm.. so if you upgraded the bootloader and the internal register address
> is now 0xf100000 then it makes sense to fix your DT accordingly.

Agreed.

> Are you enabling CONFIG_DEBUG_LL? In that case, please note there's a
> new option that will let you move to the 'new' internal regs address.

The option is CONFIG_DEBUG_MVEBU_UART.  Since you swapped out the
bootloader, you need to tell it so.  (Early printk assumes the
bootloader setup the uart and just writes to it blindly.  If it's at a
different address than expected, it'll crash.)

hth,

Jason.