MMC prepare for zynq

[Michael Graichen]

Am 5. Juli 2025 09:01:38 MESZ schrieb Gwenhael Goavec-Merou <gwenj at trabucayre.com>:
>Hi,
>Thanks for informations: after deleting everything but the last two lines, barebox starts has expected.
>Now I have and error with SDCard but maybe related to lines removes or something similar.
>

Hey, 

please show me the error messages once you put #define DEBUG at the top of mci-core.c

I'm also using a patches Version of drivers/mci/mci-core.c 

First thing is that the amplitude of SD-Cards clock signal decreases with higher speed on Zynq-7000. I had to reduce SD-Cards speed to 25MHz within lowlevel.c. Next thing is mci-core.c does some speed and line testing that then causes error messages for my eMMC on the other line. So I skip this tests. 

Since the board i'm working on doesn't change anymore, that's fine to me. But probably will not be good for other boards using mci-core.c 

A feature to define fixed line nummers and speed mode from devicetree would be nice here?!

Have and nice weekend,
Michael



>Thanks!
>
>Gwenhael
>
>Le 04/07/2025 à 7:38 PM, Johannes Roith a écrit :
>> Hi Gwenhael, hi Ahmad
>> 
>> Am Fri, Jul 04, 2025 at 04:56:01PM +0200 schrieb Ahmad Fatoum:
>>> Hi Gwenhael,
>>> 
>>> On 7/3/25 09:18, Gwenhael Goavec-Merou wrote:
>>>> Dear all,
>>>> 
>>>> I'm trying to uses my zedboard with barebox but can't be able to boot this.
>>>> 
>>>> According to mails found in this mailing list I have done this sequence:
>>>> 
>>>> export ARCH=arm
>>>> export CROSS_COMPILE=$SOMEWHERE/arm-buildroot-linux-gnueabihf-
>>>> 
>>>> make zynq_defconfig
>>>> make -j$(nproc)
>>> 
>>> That looks correct IMO.
>>> 
>>>> And copied in the first SDCard FAT partition:
>>>> - images/barebox-avnet-zedboard.img as BOOT.bin
>>>> - barebox.bin
>>> 
>>> Which binary is barebox.bin?
>> 
>> The first one is the correct one. Just copy the images/barebox-avnet-zedboard.img
>> with the name BOOT.bin to an SD-Card whose first partition is FAT32.
>>> 
>>>> But I have nothing displayed through serial port.
>>> 
>>> Two things come to mind:
>>> 
>>> - The Image is 184K. Does the Zynq enforce a maximum limit on the BOOT.BIN?
>> 
>> Yes, there is a limitation for the size of the First Stage Bootloader
>> (FSBL) as Xilinx calls it, which is the available SRAM size in the ZYNQ
>> 7000 (192 kBytes). Currently Barebox PBL and Barebox Proper are combined
>> to one image (images/barebox-avnet-zedboard.img) but you will get an
>> error in the build process, if your image exceeds this size.
>>> 
>>> - Does DEBUG_LL produce any output? For details on how to configure
>>> DEBUG_LL, see the troubleshooting guide I just Cc'd you on.
>>> 
>>>> Are there somewhere details on how to prepare SD Card for a zynq board?
>>> 
>>> I haven't done work with the Zynq 7000 so far, but Lucas and Johannes
>>> did. I Cc'd them as they may be able to give some tips for troubleshooting.
>> 
>> I would also take a look at this message on the mailing list:
>> 
>> https://lore.barebox.org/barebox/DB7PR02MB43323CD77E0507E560475BCAABF00@DB7PR02MB4332.eurprd02.prod.outlook.com/
>> 
>> Here, the content of the file
>> arch/arm/boards/avnet-zedboard/zedboard.zynqcfg caused a boot error for
>> barebox. With my Digilent Cora Z7 board, I also had to modify the file
>> by deleting everything but the last line, to get barebox booting. Have
>> you already tried this?
>> 
>>> 
>>> Cheers,
>>> Ahmad
>>> 
>>>> 
>>>> Thanks
>>>> 
>>>> Gwenhael
>>>> 
>>>> 
>>> 
>>> -- 
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>>> 
>> 
>> Best regards,
>> Johannes
>
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