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

[Michal Simek]

On 11.7.2018 22:13, Simon Glass wrote:
> 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.

Does it make sense to simply remove that line? At least I would like to
keep it enable for microblaze/zynq/zynqmp boards but not sure about
others. Or simply update every defconfig and enable it there to have
zero diff?

Thanks,
Michal