From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from zimbra2.kalray.eu ([92.103.151.219]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iuIGX-0007fh-Ae for barebox@lists.infradead.org; Wed, 22 Jan 2020 15:50:14 +0000 Received: from localhost (localhost [127.0.0.1]) by zimbra2.kalray.eu (Postfix) with ESMTP id BF8D627E102A for ; Wed, 22 Jan 2020 16:49:59 +0100 (CET) From: Jules Maselbas Date: Wed, 22 Jan 2020 16:49:42 +0100 Message-Id: <20200122154950.22746-2-jmaselbas@kalray.eu> In-Reply-To: <20200122154950.22746-1-jmaselbas@kalray.eu> References: <20200122154950.22746-1-jmaselbas@kalray.eu> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [RFC PATCH 1/9] BACKPORT: usb: Add helper to extract bits 12:11 of wMaxPacketize To: Barebox List Cc: Jules Maselbas 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. (cherry picked from linux commit 541b6fe63023f3059cf85d47ff2767a3e42a8e44) Signed-off-by: Jules Maselbas --- include/usb/ch9.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/include/usb/ch9.h b/include/usb/ch9.h index 85f3e64ca..fc6ec862c 100644 --- a/include/usb/ch9.h +++ b/include/usb/ch9.h @@ -1,3 +1,4 @@ + /* * This file holds USB constants and structures that are needed for * USB device APIs. These are used by the USB device model, which is @@ -400,6 +401,11 @@ 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) @@ -596,6 +602,20 @@ static inline int usb_endpoint_is_isoc_out( return usb_endpoint_xfer_isoc(epd) && usb_endpoint_dir_out(epd); } +/** + * 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; +} + /** * usb_endpoint_maxp - get endpoint's max packet size * @epd: endpoint to be checked -- 2.21.0.196.g041f5ea _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox