[U-Boot] USB failure on i.MX7 based module with v2019.07

[U-Boot] USB failure on i.MX7 based module with v2019.07

[Thomas Schaefer]

Hi Marek,

I have ported u-boot v2019.07 to our i.MX7 base custom board. When testing, I found that 'usb start' command results in board reset due to data abort exception.

Our board has usbotg1, usbotg2 and usbh ports enabled. It works fine with older u-boot versions.

I did some investigation and found that the reason is based on index calculation of USB ports introduced with your commit 
501547cec1f7f0438cae388a104ff60f18576c01. Here, 'address' and 'size' parameters of the USB controller 'reg' property in the device tree is used to calculate USB port/index number. Because controller register spacing is 0x10000 on i.MX7 and device tree 'size' entry is 0x200, this calculation results in 0, 128 and 256 as port numbers leading to driver crash later on.

My first idea was to modify the device tree nodes and actually USB works fine on my board when setting the size parameter to 0x10000. Thus I wanted to push this upstream , but after some discussion on linux-arm-kernel list (see https://patchwork.kernel.org/patch/11121805/), I think that this would be the wrong solution.

So, do you have another idea how to fix this issue?

Best regards,
Thomas


Thomas Schäfer
SW Design Engineer

Kontron - An S&T Company
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