Re: [PATCH v8 1/2] usb: hub : Add devaddr in struct usb_device

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, May 10, 2019 at 05:02:16PM +0800, Jim Lin wrote:
> The Clear_TT_Buffer request sent to the hub includes the address of
> the LS/FS child device in wValue field. usb_hub_clear_tt_buffer()
> uses udev->devnum to set the address wValue. This won't work for
> devices connected to xHC.
> 
> For other host controllers udev->devnum is the same as the address of
> the usb device, chosen and set by usb core. With xHC the controller
> hardware assigns the address, and won't be the same as devnum.
> 
> Here we add devaddr in "struct usb_device" for
> usb_hub_clear_tt_buffer() to use.
> 
> Signed-off-by: Jim Lin <jilin@nvidia.com>
> ---
> v2: xhci_clear_tt_buffer_complete: add static, shorter indentation
>     , remove its claiming in xhci.h
> v3: Add description for clearing_tt (xhci.h)
> v4: Remove clearing_tt flag because hub_tt_work has hub->tt.lock
>     to protect for Clear_TT_Buffer to be run serially.
>     Remove xhci_clear_tt_buffer_complete as it's not necessary.
>     Same reason as the above.
>     Extend usb_hub_clear_tt_buffer parameter
> v5: Not extending usb_hub_clear_tt_buffer parameter
>     Add description.
> v6: Remove unused parameter slot_id from xhci_clear_hub_tt_buffer
> v7: Add devaddr field in "struct usb_device"
> v8: split as two patches, change type from int to u8 for devaddr.
> 
>  drivers/usb/core/hub.c | 4 +++-
>  include/linux/usb.h    | 2 ++
>  2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 15a2934dc29d..078894023797 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -873,7 +873,7 @@ int usb_hub_clear_tt_buffer(struct urb *urb)
>  	/* info that CLEAR_TT_BUFFER needs */
>  	clear->tt = tt->multi ? udev->ttport : 1;
>  	clear->devinfo = usb_pipeendpoint (pipe);
> -	clear->devinfo |= udev->devnum << 4;
> +	clear->devinfo |= (u16) (udev->devaddr << 4);
>  	clear->devinfo |= usb_pipecontrol(pipe)
>  			? (USB_ENDPOINT_XFER_CONTROL << 11)
>  			: (USB_ENDPOINT_XFER_BULK << 11);
> @@ -2125,6 +2125,8 @@ static void update_devnum(struct usb_device *udev, int devnum)
>  	/* The address for a WUSB device is managed by wusbcore. */
>  	if (!udev->wusb)
>  		udev->devnum = devnum;
> +	if (!udev->devaddr)
> +		udev->devaddr = (u8) devnum;

Checkpatch did not complain here?  Or above?  Please don't put a space
before the ) when casting.


>  }
>  
>  static void hub_free_dev(struct usb_device *udev)
> diff --git a/include/linux/usb.h b/include/linux/usb.h
> index 4229eb74bd2c..db38c13a6b1d 100644
> --- a/include/linux/usb.h
> +++ b/include/linux/usb.h
> @@ -565,6 +565,7 @@ struct usb3_lpm_parameters {
>   * @tx_lanes: number of tx lanes in use, USB 3.2 adds dual-lane support
>   * @tt: Transaction Translator info; used with low/full speed dev, highspeed hub
>   * @ttport: device port on that tt hub
> + * @devaddr: device address, XHCI: assigned by HW, others: same as devnum
>   * @toggle: one bit for each endpoint, with ([0] = IN, [1] = OUT) endpoints
>   * @parent: our hub, unless we're the root
>   * @bus: bus we're part of
> @@ -641,6 +642,7 @@ struct usb_device {
>  
>  	struct usb_tt	*tt;
>  	int		ttport;
> +	u8 devaddr;

That's some horrible variable alignment :(

Please use pahole to find a better place to put it.

thanks,

greg k-h