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

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Message-Id: <1479471446-19435-1-git-send-email-tal.shorer@gmail.com>
Date:   Fri, 18 Nov 2016 14:17:26 +0200
From:   Tal Shorer <tal.shorer@...il.com>
To:     gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Tal Shorer <tal.shorer@...il.com>
Subject: [PATCH v3] usb: hcd.h: construct hub class request constants from simpler constants

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