linux-kernel - Re: [PATCH v3] usb: hcd.h: construct hub class request constants from simpler constants

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Message-ID: <CAFDyS3MLd__aKrNc6VbXd9tx38-j6+FEdmUh-4mLd=62DcDDtQ@mail.gmail.com>
Date:   Sat, 3 Dec 2016 15:52:17 +0200
From:   Tal Shorer <tal.shorer@...il.com>
To:     "<gregkh@...uxfoundation.org>" <gregkh@...uxfoundation.org>,
        USB list <linux-usb@...r.kernel.org>,
        "<linux-kernel@...r.kernel.org>" <linux-kernel@...r.kernel.org>
Cc:     Tal Shorer <tal.shorer@...il.com>
Subject: Re: [PATCH v3] usb: hcd.h: construct hub class request constants from
 simpler constants

On Fri, Nov 18, 2016 at 2:17 PM, Tal Shorer <tal.shorer@...il.com> wrote:
> Currently, each hub class request constant is defined by a line like:
> #define ClearHubFeature         (0x2000 | USB_REQ_CLEAR_FEATURE)
>
> The "magic" number for the high byte is one of 0x20, 0xa0, 0x23, 0xa3.
> The 0x80 bit that changes inditace USB_DIR_IN, and the 0x03 that
> pops up is the difference between USB_RECIP_DEVICE (0x00) and
> USB_RECIP_OTHER (0x03). The constant 0x20 bit is USB_TYPE_CLASS.
>
> This patch eliminates those magic numbers by defining a macro to help
> construct these hub class request from simpler constants.
> Note that USB_RT_HUB is defined as (USB_TYPE_CLASS | USB_RECIP_DEVICE)
> and that USB_RT_PORT is defined as (USB_TYPE_CLASS | USB_RECIP_OTHER).
>
> Signed-off-by: Tal Shorer <tal.shorer@...il.com>
> ---
>  include/linux/usb/hcd.h | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
> index 66fc137..40edf6a 100644
> --- a/include/linux/usb/hcd.h
> +++ b/include/linux/usb/hcd.h
> @@ -566,21 +566,22 @@ extern void usb_ep0_reinit(struct usb_device *);
>         ((USB_DIR_OUT|USB_TYPE_STANDARD|USB_RECIP_INTERFACE)<<8)
>
>  /* class requests from the USB 2.0 hub spec, table 11-15 */
> +#define HUB_CLASS_REQ(dir, type, request) ((((dir) | (type)) << 8) | (request))
>  /* GetBusState and SetHubDescriptor are optional, omitted */
> -#define ClearHubFeature                (0x2000 | USB_REQ_CLEAR_FEATURE)
> -#define ClearPortFeature       (0x2300 | USB_REQ_CLEAR_FEATURE)
> -#define GetHubDescriptor       (0xa000 | USB_REQ_GET_DESCRIPTOR)
> -#define GetHubStatus           (0xa000 | USB_REQ_GET_STATUS)
> -#define GetPortStatus          (0xa300 | USB_REQ_GET_STATUS)
> -#define SetHubFeature          (0x2000 | USB_REQ_SET_FEATURE)
> -#define SetPortFeature         (0x2300 | USB_REQ_SET_FEATURE)
> +#define ClearHubFeature                HUB_CLASS_REQ(USB_DIR_OUT, USB_RT_HUB, USB_REQ_CLEAR_FEATURE)
> +#define ClearPortFeature       HUB_CLASS_REQ(USB_DIR_OUT, USB_RT_PORT, USB_REQ_CLEAR_FEATURE)
> +#define GetHubDescriptor       HUB_CLASS_REQ(USB_DIR_IN, USB_RT_HUB, USB_REQ_GET_DESCRIPTOR)
> +#define GetHubStatus           HUB_CLASS_REQ(USB_DIR_IN, USB_RT_HUB, USB_REQ_GET_STATUS)
> +#define GetPortStatus          HUB_CLASS_REQ(USB_DIR_IN, USB_RT_PORT, USB_REQ_GET_STATUS)
> +#define SetHubFeature          HUB_CLASS_REQ(USB_DIR_OUT, USB_RT_HUB, USB_REQ_SET_FEATURE)
> +#define SetPortFeature         HUB_CLASS_REQ(USB_DIR_OUT, USB_RT_PORT, USB_REQ_SET_FEATURE)
>
>
>  /*-------------------------------------------------------------------------*/
>
>  /* class requests from USB 3.1 hub spec, table 10-7 */
> -#define SetHubDepth            (0x2000 | HUB_SET_DEPTH)
> -#define GetPortErrorCount      (0xa300 | HUB_GET_PORT_ERR_COUNT)
> +#define SetHubDepth            HUB_CLASS_REQ(USB_DIR_OUT, USB_RT_HUB, HUB_SET_DEPTH)
> +#define GetPortErrorCount      HUB_CLASS_REQ(USB_DIR_IN, USB_RT_PORT, HUB_GET_PORT_ERR_COUNT)
>
>  /*
>   * Generic bandwidth allocation constants/support
> --
> 2.5.0
>
ping?