Hi Simon, Siarhei,
On 01-02-15 21:59, Simon Glass wrote:
Hi Siarhei,
On 1 February 2015 at 11:37, Siarhei Siamashka <siarhei.siamas...@gmail.com>
<snip>
A comprehensive FEL usage guide is supposed to be in the linux-sunxi
wiki. But it might be not very up to date with the mainline u-boot
usage.
Anyway, first just clone the https://github.com/linux-sunxi/sunxi-tools
repository and build it. This will provide you with the x86 binary of
the 'fel' tool, which is used on your desktop PC to talk with the
device.
Then connect the device to your PC using a "USB A to USB mini/micro B"
cable. And reset the board while keeping the "FEL" button pressed. The
button might be labelled as "UPGRADE" on your pcduino3 board:
http://linux-sunxi.org/LinkSprite_pcDuino_V3#FEL_mode
Then just run "fel ver" command:
http://linux-sunxi.org/FEL#Running_the_fel_tool
If everything is fine, it should respond with something like this:
AWUSBFEX soc=00162500(A13) 00000001 ver=0001 44 08 scratchpad=00007e00
00000000 00000000
Now you can use "write" commands to upload data to SRAM. And "exe"
command to execute functions on the device (works as some kind of RPC):
http://linux-sunxi.org/FEL/USBBoot#Manual_loading
As a simple test, you can upload just a single "bx lr" instruction
(compiled in ARM mode) to the address 0x2000 and try to execute it.
In the case if your code screws up something and does not return
control to the BROM correctly, then the "fel" tool can't communicate
over USB anymore and just timeouts. Regarding the address space, you
can use SRAM addresses starting from 0x2000 up to something like 0x5E00
(that's where the stack pointer is set). This was a description of a
"bare metal" FEL usage.
Now as for the u-boot support. You can compile and run u-boot in the FEL
mode configuration on pcduino3 in the following way:
make CROSS_COMPILE=arm-none-gnueabi- Linksprite_pcDuino3_felconfig
make CROSS_COMPILE=arm-none-gnueabi- -j2
fel write 0x2000 spl/u-boot-spl.bin
fel exe 0x2000
sleep 1 # Wait for DRAM initialization to complete
i.e. wait for U-Boot SPL to return to the BROM?
fel write 0x4a000000 u-boot.bin
fel exe 0x4a000000
Please note the use of '*_felconfig' instead of '*_defconfig'.
And also right now the FEL mode support is broken. That's why the
http://lists.denx.de/pipermail/u-boot/2015-January/203282.html
patchset tried to address this problem.
OK that looks like an excellent guide, thank you. I will make some time to
take a more detailed look at this as soon as I can, but definitely in the
next few days.
I've been reading all threads on this, thank you both for looking into this,
since you're on it I'm going to leave this be (and not review / apply
Siarhei's patches for this), and we can revisit this later, with hopefully a
better fix.
Thanks & Regards,
Hans
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