[U-Boot] [PATCH 2/2] Add i.MX7D based Meerkat96 board support

[Manivannan Sadhasivam]

On Mon, Jul 08, 2019 at 05:59:04PM +0800, Shawn Guo wrote:
> On Mon, Jul 08, 2019 at 02:42:54PM +0530, Manivannan Sadhasivam wrote:
> > Hi Shawn,
> > 
> > Thanks for the patch!
> > 
> > On Sun, Jul 07, 2019 at 08:59:55PM +0800, Shawn Guo wrote:
> > > The Meerkat96 board, based on the NXP i.MX7D SoC, is a member of
> > > 96Boards community and complies with all Consumer Edition board
> > > specifications.
> > > 
> > > https://www.novtech.com/products/meerkat96.html
> > > https://www.96boards.org/product/imx7-96/
> > > 
> > > The initial supported/tested devices include:
> > >  - Debug serial
> > >  - SD
> > >  - USB Host (with Ethernet)
> > 
> > While testing, I encountered below error when starting usb:
> > 
> > => usb start
> > starting USB...
> > Bus usb at 30b10000: usb dr_mode not found
> > Error enabling VBUS supply
> > probe failed, error -38
> 
> This is expected, as there are some properties missing from DT for
> USBOTG1, and I haven't put effort on it yet.
> 

This is fine.

> > Bus usb at 30b20000: data abort
> > pc : [<9ffaf574>]          lr : [<9ffaf560>]
> > reloc pc : [<87828574>]    lr : [<87828560>]
> > sp : 9df7d1b0  ip : 431bde82     fp : 9ff9dc8c
> > r10: 00000000  r9 : 9df84ed8     r8 : 00000000
> > r7 : 9df865d8  r6 : 9df86578     r5 : 9df87680  r4 : 00000080
> > r3 : 00000000  r2 : 0196f7b6     r1 : 31310000  r0 : 00000000
> > Flags: nZCv  IRQs off  FIQs off  Mode SVC_32
> > Code: 18bd8010 e2841dc2 e2811031 e1a01801 (e5913234) 
> > Resetting CPU ...
> > 
> > resetting ...
> 
> It looks the exception comes from USBOTG2 which backs both Host ports on
> Meerkat96 board.  I have never seen this in my testing.  Do you have any
> USB device connected to the Host port, when this happens?
> 

Digged into this issue and found that the below commit is causing regression:

501547cec1 ("usb: ehci-mx6: Fix bus enumeration for DM case")

But as mentioned in the commit message, that commit was incomplete and this
issue might be expected. Reverting the commit makes usb work again. And the
reason you are not seeing this issue is, your tree might not be updated
with mainline u-boot ;-)

Copied Marek who was the author of that commit.

With that, you can have my tested tag:

Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>

Thanks,
Mani

> > 
> > Did I miss anything? Sorry, don't have time to debug much...
> 
> If you can help me reproduce it on my end, I will debug it.
> 
> Shawn