[U-Boot] [PATCH v4 2/9] dm: usb: Copy over usb_device values from usb_scan_device() to final usb_device

[Simon Glass]

On 5 May 2015 at 03:54, Hans de Goede <hdegoede at 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 3 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.
>
> 2) It unnecessarily redoes a number of usb requests making usb probing slower
>
> 3) Calling usb_select_config() a second time fails on some usb-1 devices
> plugged into usb-2 hubs, causing u-boot to not recognize these devices.
>
> This commit fixes these 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.
>
> *) Except for devices which are explictly instantiated through device-tree
> rather then discovered through usb_scan_device() such as emulated usb devices
> in the sandbox.
>
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> ---
> Changes in v3:
> -Add a big fat comment to warn that plat->udev is for usb-uclass.c internal
>  use only
> Changes in v4:
> -Fix sandbox emul usb device breakage
> ---
>  drivers/usb/host/usb-uclass.c | 43 ++++++++++++++++++++++++++++---------------
>  include/usb.h                 | 17 ++++++++++-------
>  2 files changed, 38 insertions(+), 22 deletions(-)

Acked-by: Simon Glass <sjg at chromium.org>