Re: [PATCH v4 1/4] cmd: bind: Add unbind command with driver filter

[Tom Rini <trini@konsulko.com>]

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On Fri, Aug 04, 2023 at 06:00:12PM +0200, Miquel Raynal wrote:
> Hi Marek,
> 
> marex@denx.de wrote on Fri, 4 Aug 2023 17:40:07 +0200:
> 
> > On 8/4/23 17:12, Miquel Raynal wrote:
> > > Hi,
> > > 
> > > marex@denx.de wrote on Fri, 4 Aug 2023 17:05:01 +0200:
> > >   
> > >> On 8/4/23 17:01, Tom Rini wrote:  
> > >>> On Fri, Aug 04, 2023 at 04:42:13PM +0200, Marek Vasut wrote:  
> > >>>> On 8/4/23 09:00, Miquel Raynal wrote:  
> > >>>>> Hi Marek,
> > >>>>>
> > >>>>> marex@denx.de wrote on Wed,  2 Aug 2023 14:46:54 +0200:  
> > >>>>>   >>>>>> Extend the driver core to perform lookup by both OF node and driver  
> > >>>>>> bound to the node. Use this to look up specific device instances to
> > >>>>>> unbind from nodes in the unbind command. One example where this is
> > >>>>>> needed is USB peripheral controller, which may have multiple gadget
> > >>>>>> drivers bound to it. The unbind command has to select that specific
> > >>>>>> gadget driver instance to unbind from the controller, not unbind the
> > >>>>>> controller driver itself from the controller.
> > >>>>>>
> > >>>>>> USB ethernet gadget usage looks as follows with this change. Notice
> > >>>>>> the extra 'usb_ether' addition in the 'unbind' command at the end.
> > >>>>>> "
> > >>>>>> bind /soc/usb-otg@49000000 usb_ether
> > >>>>>> setenv ethact usb_ether
> > >>>>>> setenv loadaddr 0xc2000000
> > >>>>>> setenv ipaddr 10.0.0.2
> > >>>>>> setenv serverip 10.0.0.1
> > >>>>>> setenv netmask 255.255.255.0
> > >>>>>> tftpboot 0xc2000000 10.0.0.1:test.file
> > >>>>>> unbind /soc/usb-otg@49000000 usb_ether  
> > >>>>>
> > >>>>> This extra parameter does not seem to work on the BBBW. I cannot select
> > >>>>> the "usb_ether" driver like you do.
> > >>>>>
> > >>>>> Good news though, I am now able to use fastboot, but it is not
> > >>>>> straightforward:
> > >>>>>
> > >>>>> Here is my sequence right after the boot (reducing the dm tree output
> > >>>>> to the usb nodes for clarity):  
> > >>>>>   >>>>> => dm tree  
> > >>>>>     misc          0  [ + ]   ti-musb-wrapper       |   |-- usb@47400000
> > >>>>>     usb           0  [ + ]   ti-musb-peripheral    |   |   |-- usb@47401000
> > >>>>>     ethernet      1  [ + ]   usb_ether             |   |   |   `-- usb_ether
> > >>>>>     bootdev       3  [   ]   eth_bootdev           |   |   |       `-- usb_ether.bootdev
> > >>>>>     usb           0  [   ]   ti-musb-host          |   |   `-- usb@47401800  
> > >>>>> => fastboot usb 0  
> > >>>>> couldn't find an available UDC
> > >>>>> g_dnl_register: failed!, error: -19  
> > >>>>
> > >>>> That is expected and not a bug, since the beagle explicitly binds USB
> > >>>> ethernet to MUSB gadget in board file, which is legacy deprecated way.  
> > >>>
> > >>> So, we should do away with, probably all of arch_misc_init() in
> > >>> arch/arm/mach-omap2/am33xx/board.c for the non-SPL case.  
> > >>
> > >> Yes
> > >>  
> > >>>>> exit not allowed from main input shell.  
> > >>>>> => unbind /ocp/usb@47400000/usb@47401000 usb_ether  
> > >>>>
> > >>>> Does  
> > >>>>   >>>> => unbind ethernet 0  
> > >>>>
> > >>>> work ?
> > >>>>
> > >>>> If so, 1/4 in this series can be skipped altogether.
> > >>>>
> > >>>> You likely won't even need the rebinding of ti-musb-peripheral anymore.  
> > 
> > Did you test this yet ?
> 
> Not yet, I'll send you the feedback once done.
> 
> > >>>>> Cannot find a device with path /ocp/usb@47400000/usb@47401000  
> > >>>>> => unbind /ocp/usb@47400000/usb@47401000
> > >>>>> => dm tree  
> > >>>>>     misc          0  [ + ]   ti-musb-wrapper       |   |-- usb@47400000
> > >>>>>     usb           0  [   ]   ti-musb-host          |   |   `-- usb@47401800  
> > >>>>> => fastboot usb 0
> > >>>>> => bind /ocp/usb@47400000/usb@47401000 ti-musb-peripheral
> > >>>>> => dm tree  
> > >>>>>     misc          0  [ + ]   ti-musb-wrapper       |   |-- usb@47400000
> > >>>>>     usb           0  [   ]   ti-musb-host          |   |   |-- usb@47401800
> > >>>>>     usb           0  [   ]   ti-musb-peripheral    |   |   `-- usb@47401000  
> > >>>>> => fastboot usb 0  
> > >>>>> musb-hdrc: peripheral reset irq lost!
> > >>>>> # works! (the irq-related line above as always been there)
> > >>>>>
> > >>>>> So now, how do we make this process easy/understandable?  
> > >>>>
> > >>>> What would be your proposal ?  
> > > 
> > > At least I would appreciate:
> > > - to select CMD_BIND "by default" when relevant
> > > - to make the fastboot error more readable for the regular user  
> > 
> > Since with this 'unbind ethernet 0' this is orthogonal to this series, send separate patches, thanks.
> 
> This is not orthogonal, I am sorry.
> 
> version X:
> - tftp works "out of the box"
> - fastboot works "out of the box"
> version X+1:
> - tftp works "out of the box"
> - fastboot returns an obscure error
> 
> 1/ If we now *need* the bind/unbind commands, the series must take care
>    of it.
> 2/ Without proper error message you just break fastboot for most
>    regular users (basically everyone but few U-Boot devs).

You're missing the class of users that will be impacted here.  In order
for there to be a change here, you have to already be in the case where
you have CONFIG_USB_ETHER=y and gadget ethernet device isn't just
enabled but also initialized by default by calling usb_ether_init().
That's a very small list.  It's basically am33xx, two mediatek reference
platforms and xilinx_zynqmp_virt.  Given that am33xx defconfigs also
setup DFU, I'm not really sure just how many people use gadget ethernet.
The normal flow on modern devices is to be calling bind/unbind here
already.

-- 
Tom

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