[U-Boot] mx6qsabrelite U-Boot from SPI-NOR

[Wolfgang Grandegger <wg@grandegger.com>]

Hi Eric,

On 01/20/2012 01:56 AM, Eric Nelson wrote:
> Hi Wolfgang,
> 
> On 01/19/2012 03:26 AM, Dirk Behme wrote:
>> Dear Wolfgang,
>>
>> On 19.01.2012 10:58, Wolfgang Grandegger wrote:
>>>
>>> Where can I find the "SPI_to_SD_loader.bin" image?
>>
>> Unfortunately, at the moment you have to ask your Freescale contact
>> for this. We
>> ping Freescale since weeks for this. Last time I heard about this
>> Freescale
>> planned to release this binary under a BSD license. They are still
>> "working
>> through the licensing details", though :(
>>
>>> What means early
>>> version of SabreLite boards?
>>
>> Most probably Eric will be able to better answer this.
>>
> 
> At this point **all** versions of SabreLite are configured to boot to SPI
> NOR through the fuses.
> 
> As Dirk mentioned, we've had some conversations about booting to SD card,
> but once the fuse is blown, it's blown.
> 
>> What I understood: Up to now, the boards boot from SPI NOR by default.
>> There was
>> some _discussion_ to change this to SD boot. Most probably "early
>> version" was
>> written while this discussion under the impression that later boards
>> might
>> switch to SD boot. To my understanding the result of this discussion
>> was that
>> this change would be difficult, though.
>>
> 
> We've discussed, but currently have no plans to support a physical switch
> to control this decision. This would involve using the "Internal" boot mode
> position of SW1 and then pulling a **bunch** of pins high or low to control
> the boot flow.
> 
> Note that all of the pins are available on connector J12 (BOOT/EIM), so it
> might be done with a small daughter-board.

OK, I see.

> 
>>> How can I select boot from SD-Card on newer versions?
>>
>> To my understanding there are no "newer versions" yet.
>>
> 
> Right.
> 
>>> And will the u-boot.imx image also boot when loaded
>>> to the SPI-NOR fash?
>>
>> Hmm, I'm not sure about this as I haven't tested this.
>>
>> Eric?
>>
> 
> Yes. If you program u-boot.imx to offset 0x400, it will boot.
> 
> I just did so as shown below.
> 
> I started by placing SW1 in the 01 position (boot to USB), and
> used imx_usb to dowload u-boot.imx:
> 
>     MX6QSABRELITE U-Boot > dhcp 10800000 192.168.0.112:u-boot.imx
>     fec_open:Speed=100
>     BOOTP broadcast 1
>     BOOTP broadcast 2
>     DHCP client bound to address 29.6.1.24
>     Using FEC device
>     TFTP from server 192.168.0.112; our IP address is 29.6.1.24;
> sending     through gateway 29.6.1.1
>     Filename 'u-boot.imx'.
>     Load address: 0x10800000
>     Loading: #########################################
>     done
>     Bytes transferred = 207112 (32908 hex)
>     MX6QSABRELITE U-Boot > sf write 0x10800000 0x400 $filesize

But above you used the network to load u-boot.imx. With imx_usb you
loaded and booted an image via USB first, I assume.

> <switched SW1 to BOOT mode 0 and hit the reset button here>
> 
>     U-Boot 2011.12-00048-g5c30101 (Jan 19 2012 - 17:14:32)
>     CPU:   Freescale i.MX61 family rev1.0 at 792 MHz
>     Reset cause: POR
>     Board: MX6Q-Sabre Lite
>     DRAM:  1 GiB
>     WARNING: Caches not enabled
>     MMC:   FSL_SDHC: 0, FSL_SDHC: 1
>     MMC init failed
>     Using default environment
> 
>     In:    serial
>     Out:   serial
>     Err:   serial
>     Net:   FEC
>     Hit any key to stop autoboot:  0
>     MX6QSABRELITE U-Boot >
>     MX6QSABRELITE U-Boot >
> 
> The imx_usb utility is available here:
>     http://boundarydevices.com/git?p=imx_usb_loader.git
> 
> It requires libusb-1.0-0-dev to build, but has few other dependencies.
> 
> Usage is simple: hand it the file you want to execute. It will look
> at the header to find out where to place the image.
>     ~/imx_usb_loader$ sudo sudo ./imx_usb u-boot.imx

Nice fallback in case the bootloader does not start. I will give it a
try a.s.a.p. We actually plan to use a BDI[23]000 for that purpose.

>> Please note that Eric is in the process of mainlining the SPI driver for
>> i.MX6, atm.
> 
> If you use my latest patch set, you can place the environment in SPI-NOR as
> well by commenting out CONFIG_ENV_IS_IN_MMC, and un-commenting
> ..._IN_SPI_FLASH
> in include/configs/mx6qsabrelite.h.

OK, that's already an excellent starting point.

Thanks.

Wolfgang.