[U-Boot] [PATCH v3 7/7] cmd: Add bind/unbind commands to bind a device to a driver from the command line

[Simon Glass]

Hi,

On 11 July 2018 at 07:40, Tom Rini <trini at konsulko.com> wrote:
>
> On Wed, Jul 11, 2018 at 03:31:39PM +0200, Michal Simek wrote:
> > On 11.7.2018 14:46, Tom Rini wrote:
> > > On Wed, Jul 11, 2018 at 07:57:13AM +0200, Michal Simek wrote:
> > >> On 10.7.2018 18:40, Tom Rini wrote:
> > >>> On Mon, Jul 09, 2018 at 11:59:57AM -0500, Joe Hershberger wrote:
> > >>>> On Mon, Jul 9, 2018 at 9:43 AM, Tom Rini <trini at konsulko.com> wrote:
> > >>>>> On Mon, Jul 09, 2018 at 08:19:44AM +0200, Michal Simek wrote:
> > >>>>>> On 30.6.2018 06:19, Simon Glass wrote:
> > >>>>>>> On 27 June 2018 at 07:13, Michal Simek <michal.simek at xilinx.com> wrote:
> > >>>>>>>> On 22.6.2018 14:25, Jean-Jacques Hiblot wrote:
> > >>>>>>>>> In some cases it can be useful to be able to bind a device to a driver from
> > >>>>>>>>> the command line.
> > >>>>>>>>> The obvious example is for versatile devices such as USB gadget.
> > >>>>>>>>> Another use case is when the devices are not yet ready at startup and
> > >>>>>>>>> require some setup before the drivers are bound (ex: FPGA which bitsream is
> > >>>>>>>>> fetched from a mass storage or ethernet)
> > >>>>>>>>>
> > >>>>>>>>> usage example:
> > >>>>>>>>>
> > >>>>>>>>> bind usb_dev_generic 0 usb_ether
> > >>>>>>>>> unbind usb_dev_generic 0 usb_ether
> > >>>>>>>>> or
> > >>>>>>>>> unbind eth 1
> > >>>>>>>>>
> > >>>>>>>>> bind /ocp/omap_dwc3 at 48380000/usb at 48390000 usb_ether
> > >>>>>>>>> unbind /ocp/omap_dwc3 at 48380000/usb at 48390000
> > >>>>>>>>>
> > >>>>>>>>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot at ti.com>
> > >>>>>>>>>
> > >>>>>>>>> ---
> > >>>>>>>>>
> > >>>>>>>>> Changes in v3:
> > >>>>>>>>> - factorize code based on comments from ML
> > >>>>>>>>> - remove the devices before unbinding them
> > >>>>>>>>> - use device_find_global_by_ofnode() to get a device by its node.
> > >>>>>>>>> - Added tests
> > >>>>>>>>>
> > >>>>>>>>> Changes in v2:
> > >>>>>>>>> - Make the bind/unbind command generic, not specific to usb device.
> > >>>>>>>>> - Update the API to be able to bind/unbind based on DTS node path
> > >>>>>>>>> - Add a Kconfig option to select the bind/unbind commands
> > >>>>>>>>>
> > >>>>>>>>>  arch/sandbox/dts/test.dts  |  11 ++
> > >>>>>>>>>  cmd/Kconfig                |   9 ++
> > >>>>>>>>>  cmd/Makefile               |   1 +
> > >>>>>>>>>  cmd/bind.c                 | 255 +++++++++++++++++++++++++++++++++++++++++++++
> > >>>>>>>>>  configs/sandbox_defconfig  |   1 +
> > >>>>>>>>>  test/py/tests/test_bind.py | 178 +++++++++++++++++++++++++++++++
> > >>>>>>>>>  6 files changed, 455 insertions(+)
> > >>>>>>>>>  create mode 100644 cmd/bind.c
> > >>>>>>>>>  create mode 100644 test/py/tests/test_bind.py
> > >>>>>>>
> > >>>>>>> Reviewed-by: Simon Glass <sjg at chromium.org>
> > >>>>>>>
> > >>>>>>> Nice work
> > >>>>>>>
> > >>>>>>> [...]
> > >>>>>>>
> > >>>>>>>>
> > >>>>>>>> I have tested bind/unbind with dwc3 on zynqmp for ethernet gadget and it
> > >>>>>>>> is working fine for me.
> > >>>>>>>> I have also tried to use bind/unbind for gpio zynqmp driver and it is
> > >>>>>>>> also working fine.
> > >>>>>>>>
> > >>>>>>>> It means
> > >>>>>>>> Tested-by: Michal Simek <michal.simek at xilinx.com>
> > >>>>>>>>
> > >>>>>>>> I would prefer if these commands are called as dm bind and dm unbind
> > >>>>>>>> instead of simply bind/unbind which should also fit to dm command
> > >>>>>>>> description "dm - Driver model low level access".
> > >>>>>>>
> > >>>>>>> Yes i can see the point. But after thinking about it, maybe it is best
> > >>>>>>> as it is? After all driver model is fundamental to U-Boot and it's not
> > >>>>>>> clear what else we might bind/unbind.
> > >>>>>>>
> > >>>>>>> I'd like to get other opinions here, too.
> > >>>>>>
> > >>>>>> Tom/Marek: Any opinion?
> > >>>>>
> > >>>>> I think dm bind/unbind makes sense, yes.  "bind" and "unbind" are pretty
> > >>>>> generic terms and making it clear it's part of working "inside" of DM to
> > >>>>> hook/unhook things by making it a sub-command of dm sounds good.
> > >>>>> Thanks!
> > >>>>
> > >>>> I agree with Simon here. I think bind and unbind won't have any
> > >>>> plausible other meaning in U-Boot and DM is core to U-Boot
> > >>>> functionality in the new world. I think it would be OK to have "dm
> > >>>> bind" alias to "bind" if that's a point of confusion, but having it
> > >>>> top-level seems good to me.
> > >>>
> > >>> They're still very generic words for something that's part of working
> > >>> under the dm framework.  That said, looking at test/dm/cmd_dm.c and that
> > >>> it's supposed to be only for test/debug type work, yes, OK, I'll change
> > >>> my mind.
> > >>
> > >> I would expect that almost everybody will enable CMD_DM where symbol is
> > >> in cmd/Kconfig but implementation in test/dm/cmd_dm.c (it is a question
> > >> if this is the right place for this file).
> > >
> > > It might well really belong as cmd/dm.c, but content wise it's debug
> > > information that is also useful in the bind/unbind case (so you know
> > > where U-Boot sees things as being at).
> >
> > Then we should really not enable it by default for all boards with DM on.
> >
> >  640 config CMD_DM
> >  641         bool "dm - Access to driver model information"
> >  642         depends on DM
> >  643         default y
>
> Simon?

I'm OK with having it disabled by default - it is for debugging after all.

Regards,
Simon