Re: [Xen-devel] Problems when booting on OMAP5432 devboard

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2013-07-01 at 20:58 +0800, Chen Baozi wrote:
> On Jul 1, 2013, at 8:43 PM, Chen Baozi <baozich@xxxxxxxxx> wrote:
> 
> > On Mon, Jul 01, 2013 at 01:39:02PM +0100, Ian Campbell wrote:
> >> On Mon, 2013-07-01 at 20:32 +0800, Chen Baozi wrote:
> >>> On Jul 1, 2013, at 8:06 PM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> >>> 
> >>>> On Mon, 2013-07-01 at 20:00 +0800, Chen Baozi wrote:
> >>>> 
> >>>>>> You device has 2GB RAM, what happens if you hack the DTS to say it only
> >>>>>> has 1GB?
> >>>>> 
> >>>>> Bingo! Compared to Arndale board, OMAP5432 uEVM's RAM is not yet 
> >>>>> 0x40000000~0xbfffffff, but 0x80000000~0xffffffff. After make the 
> >>>>> following change to DTS:
> >>>>> 
> >>>>>         memory {
> >>>>>                 device_type = "memory"
> >>>>> -               reg = <0x80000000 0x80000000>; /* 2 GB */
> >>>>> +               reg = <0x80000000 0x40000000>; /* 1 GB */
> >>>>>         };
> >>>>> 
> >>>>> I can reach the output "Xen heap: 131072 pages  Dom heap: 131072 
> >>>>> pages". 
> >>>> 
> >>>> Excellent!
> >>>> 
> >>>> So I guess if you keep the 2GB but put it at the right address it will
> >>>> also work?
> >>> 
> >>> I'm afraid no, :-(
> >>> 
> >>> Here is how I load and boot the image both in 1GB case and 2G case (from 
> >>> u-boot):
> >>> 
> >>> OMAP5430 EVM # fatload mmc 0 0x80000000 xen-uImage
> >>> reading xen-uImage
> >>> 902572 bytes read in 59 ms (14.6 MiB/s)
> >>> OMAP5430 EVM # bootm 0x80000000 -
> >>> ## Booting kernel from Legacy Image at 80000000 ...
> >>>   Image Name:
> >>>   Image Type:   ARM Linux Kernel Image (uncompressed)
> >>>   Data Size:    902508 Bytes = 881.4 KiB
> >>>   Load Address: 80200000
> >>>   Entry Point:  80200000
> >>>   Verifying Checksum ... OK
> >>>   Loading Kernel Image ... OK
> >>> OK
> >> 
> >>> And I've also tried "fat load mmc 0 0x90000000 xen-uImage" in both
> >>> cases. It works for 1GB but fails in 2GB case too.
> >> 
> >> What is the base address of RAM on the A31 SoC?
> > 
> > A31 SoC? I use OMAP5432 ES2.0 uEVM (OMAP5 Panda) board.
> > 
> > The attachment is the dts file which the linux kernel uses on this board by
> > default, which the memory line is:
> > 
> >     reg = <0x80000000 0x80000000>; /* 2 GB */
> > 
> However, interestingly, in omap5-evm.dts, it writes:
> 
>       reg = <0x80000000 0x7F000000>; /* 2032 MB */
> 
> And if I use this line, it works!
> 
> So I think this might be the point.

Huzzah!

It certainly is important to use a DTB which accurately describes the
exact hardware.

I bet some RAM is carved out for video RAM or secure world use or
something...

Ian.


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