[U-Boot] [PATCH 1/8] dm: usb: Copy over usb_device values from usb_scan_device() to final usb_device

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 01-05-15 06:11, Simon Glass wrote:
> Hi Hans,
>
> On 30 April 2015 at 08:35, Hans de Goede <hdegoede@redhat.com> wrote:
>> Currently we copy over a number of usb_device values stored in the on stack
>> struct usb_device probed in usb_scan_device() to the final driver-model managed
>> struct usb_device in usb_child_pre_probe() through usb_device_platdata, and
>> then call usb_select_config() to fill in the rest.
>>
>> There are 2 problems with this approach:
>>
>> 1) It does not fill in enough fields before calling usb_select_config(),
>> specifically it does not fill in ep0's maxpacketsize causing a div by zero
>> exception in the ehci driver.
>
> Didn't you have another patch that fixes that?

Yes, but as explained in the coverletter of that patch I believe that
this version is better. It would seem we disagree on that though :)

>> 2) It unnecessarily redoes a number of usb requests making usb probing slower,
>> and potentially upsetting some devices.
>
> Does it actually upset anything?

Not to my knowledge, but I'm afraid that with some devices it may.

> The extra requests are in the second call to usb_select_config().

Correct.

> Do you think we could put the things we want to copy in a struct, and
> copy just those?

We would end up pretty much duplicating usb_device AFAICT, since we need
the descriptors, the max packet sizes per endpoint parsed from them, etc.

Anyways since you clearly dislike this patch I'll drop it for v2, replacing
it with my original fix for the ep0 maxpacket not being set issue, assuming
that doing so does not cause any regressions during my testing.

Regards,

Hans


>
>>
>> This commit fixes both issues by removing the usb_select_config() call from
>> usb_child_pre_probe(), and instead of copying over things field by field
>> through usb_device_platdata, store a pointer to the in stack usb_device
>> (which is still valid when usb_child_pre_probe() gets called) and copy
>> over the entire struct.
>>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>>   drivers/usb/host/usb-uclass.c | 27 ++++++---------------------
>>   include/usb.h                 |  5 +----
>>   2 files changed, 7 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/usb/host/usb-uclass.c b/drivers/usb/host/usb-uclass.c
>> index 714bc0e..95e371d 100644
>> --- a/drivers/usb/host/usb-uclass.c
>> +++ b/drivers/usb/host/usb-uclass.c
>> @@ -535,12 +535,7 @@ int usb_scan_device(struct udevice *parent, int port,
>>          }
>>          plat = dev_get_parent_platdata(dev);
>>          debug("%s: Probing '%s', plat=%p\n", __func__, dev->name, plat);
>> -       plat->devnum = udev->devnum;
>> -       plat->speed = udev->speed;
>> -       plat->slot_id = udev->slot_id;
>> -       plat->portnr = port;
>> -       debug("** device '%s': stashing slot_id=%d\n", dev->name,
>> -             plat->slot_id);
>> +       plat->udev = udev;
>>          priv->next_addr++;
>>          ret = device_probe(dev);
>>          if (ret) {
>> @@ -599,25 +594,15 @@ int usb_get_bus(struct udevice *dev, struct udevice **busp)
>>
>>   int usb_child_pre_probe(struct udevice *dev)
>>   {
>> -       struct udevice *bus;
>>          struct usb_device *udev = dev_get_parentdata(dev);
>>          struct usb_dev_platdata *plat = dev_get_parent_platdata(dev);
>> -       int ret;
>>
>> -       ret = usb_get_bus(dev, &bus);
>> -       if (ret)
>> -               return ret;
>> -       udev->controller_dev = bus;
>> +       /*
>> +        * Copy over all the values set in the on stack struct usb_device in
>> +        * usb_scan_device() to our final struct usb_device for this dev.
>> +        */
>> +       *udev = *(plat->udev);
>>          udev->dev = dev;
>> -       udev->devnum = plat->devnum;
>> -       udev->slot_id = plat->slot_id;
>> -       udev->portnr = plat->portnr;
>> -       udev->speed = plat->speed;
>> -       debug("** device '%s': getting slot_id=%d\n", dev->name, plat->slot_id);
>> -
>> -       ret = usb_select_config(udev);
>> -       if (ret)
>> -               return ret;
>>
>>          return 0;
>>   }
>> diff --git a/include/usb.h b/include/usb.h
>> index 1984e8f..1b667ff 100644
>> --- a/include/usb.h
>> +++ b/include/usb.h
>> @@ -581,10 +581,7 @@ struct usb_platdata {
>>    */
>>   struct usb_dev_platdata {
>>          struct usb_device_id id;
>> -       enum usb_device_speed speed;
>> -       int devnum;
>> -       int slot_id;
>> -       int portnr;     /* Hub port number, 1..n */
>> +       struct usb_device *udev;
>>   #ifdef CONFIG_SANDBOX
>>          struct usb_string *strings;
>>          /* NULL-terminated list of descriptor pointers */
>> --
>> 2.3.6
>>
>
> Regards,
> Simon
>