Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937953AbdCJOYE (ORCPT ); Fri, 10 Mar 2017 09:24:04 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:42439 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933723AbdCJLvK (ORCPT ); Fri, 10 Mar 2017 06:51:10 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Felipe Balbi" Date: Fri, 10 Mar 2017 11:46:22 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 013/370] usb: add helper to extract bits 12:11 of wMaxPacketSize In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2197 Lines: 68 3.16.42-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Felipe Balbi commit 541b6fe63023f3059cf85d47ff2767a3e42a8e44 upstream. According to USB Specification 2.0 table 9-4, wMaxPacketSize is a bitfield. Endpoint's maxpacket is laid out in bits 10:0. For high-speed, high-bandwidth isochronous endpoints, bits 12:11 contain a multiplier to tell us how many transactions we want to try per uframe. This means that if we want an isochronous endpoint to issue 3 transfers of 1024 bytes per uframe, wMaxPacketSize should contain the value: 1024 | (2 << 11) or 5120 (0x1400). In order to make Host and Peripheral controller drivers' life easier, we're adding a helper which returns bits 12:11. Note that no care is made WRT to checking endpoint type and gadget's speed. That's left for drivers to handle. Signed-off-by: Felipe Balbi Signed-off-by: Ben Hutchings --- include/uapi/linux/usb/ch9.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) --- a/include/uapi/linux/usb/ch9.h +++ b/include/uapi/linux/usb/ch9.h @@ -398,6 +398,11 @@ struct usb_endpoint_descriptor { #define USB_ENDPOINT_XFER_INT 3 #define USB_ENDPOINT_MAX_ADJUSTABLE 0x80 +#define USB_EP_MAXP_MULT_SHIFT 11 +#define USB_EP_MAXP_MULT_MASK (3 << USB_EP_MAXP_MULT_SHIFT) +#define USB_EP_MAXP_MULT(m) \ + (((m) & USB_EP_MAXP_MULT_MASK) >> USB_EP_MAXP_MULT_SHIFT) + /* The USB 3.0 spec redefines bits 5:4 of bmAttributes as interrupt ep type. */ #define USB_ENDPOINT_INTRTYPE 0x30 #define USB_ENDPOINT_INTR_PERIODIC (0 << 4) @@ -605,6 +610,20 @@ static inline int usb_endpoint_maxp(cons return __le16_to_cpu(epd->wMaxPacketSize); } +/** + * usb_endpoint_maxp_mult - get endpoint's transactional opportunities + * @epd: endpoint to be checked + * + * Return @epd's wMaxPacketSize[12:11] + 1 + */ +static inline int +usb_endpoint_maxp_mult(const struct usb_endpoint_descriptor *epd) +{ + int maxp = __le16_to_cpu(epd->wMaxPacketSize); + + return USB_EP_MAXP_MULT(maxp) + 1; +} + static inline int usb_endpoint_interrupt_type( const struct usb_endpoint_descriptor *epd) {