From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_RED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87DF5C4332E for ; Mon, 28 Dec 2020 14:55:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 63AC1208B6 for ; Mon, 28 Dec 2020 14:55:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392448AbgL1OzZ (ORCPT ); Mon, 28 Dec 2020 09:55:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:52532 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392412AbgL1OzY (ORCPT ); Mon, 28 Dec 2020 09:55:24 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 16777208B6; Mon, 28 Dec 2020 14:54:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609167283; bh=OB9GSFznhLtvuHSfm/O4Dzqvt2pvpOth/BfAMkwdO3c=; h=Subject:To:From:Date:From; b=mb2gGfGHfWOEOq8CoUS1Y3p0CKGGzNuSr+SD+lMp0Kc1VVDNdgfC90LpCaxca+wXQ lyjpZcrDPOZ36tPB2nLrFlZuRwv3RtYAUpYJZHwW5UOMwFL2xCo2Akl/+k+Z6opjGn rifvra2NhXgmAPPhM3gIVO16H+E3MFl/2bVzzWxU= Subject: patch "usb: dwc3: ulpi: Replace CPU-based busyloop with Protocol-based one" added to usb-linus To: Sergey.Semin@baikalelectronics.ru, gregkh@linuxfoundation.org, heikki.krogerus@linux.intel.com, stable@vger.kernel.org From: Date: Mon, 28 Dec 2020 15:55:57 +0100 Message-ID: <1609167357196109@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled usb: dwc3: ulpi: Replace CPU-based busyloop with Protocol-based one to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From fca3f138105727c3a22edda32d02f91ce1bf11c9 Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Thu, 10 Dec 2020 11:50:07 +0300 Subject: usb: dwc3: ulpi: Replace CPU-based busyloop with Protocol-based one Originally the procedure of the ULPI transaction finish detection has been developed as a simple busy-loop with just decrementing counter and no delays. It's wrong since on different systems the loop will take a different time to complete. So if the system bus and CPU are fast enough to overtake the ULPI bus and the companion PHY reaction, then we'll get to take a false timeout error. Fix this by converting the busy-loop procedure to take the standard bus speed, address value and the registers access mode into account for the busy-loop delay calculation. Here is the way the fix works. It's known that the ULPI bus is clocked with 60MHz signal. In accordance with [1] the ULPI bus protocol is created so to spend 5 and 6 clock periods for immediate register write and read operations respectively, and 6 and 7 clock periods - for the extended register writes and reads. Based on that we can easily pre-calculate the time which will be needed for the controller to perform a requested IO operation. Note we'll still preserve the attempts counter in case if the DWC USB3 controller has got some internals delays. [1] UTMI+ Low Pin Interface (ULPI) Specification, Revision 1.1, October 20, 2004, pp. 30 - 36. Fixes: 88bc9d194ff6 ("usb: dwc3: add ULPI interface support") Acked-by: Heikki Krogerus Signed-off-by: Serge Semin Link: https://lore.kernel.org/r/20201210085008.13264-3-Sergey.Semin@baikalelectronics.ru Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/dwc3/ulpi.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/usb/dwc3/ulpi.c b/drivers/usb/dwc3/ulpi.c index 3cc4f4970c05..54c877f7b51d 100644 --- a/drivers/usb/dwc3/ulpi.c +++ b/drivers/usb/dwc3/ulpi.c @@ -7,6 +7,8 @@ * Author: Heikki Krogerus */ +#include +#include #include #include "core.h" @@ -17,12 +19,22 @@ DWC3_GUSB2PHYACC_ADDR(ULPI_ACCESS_EXTENDED) | \ DWC3_GUSB2PHYACC_EXTEND_ADDR(a) : DWC3_GUSB2PHYACC_ADDR(a)) -static int dwc3_ulpi_busyloop(struct dwc3 *dwc) +#define DWC3_ULPI_BASE_DELAY DIV_ROUND_UP(NSEC_PER_SEC, 60000000L) + +static int dwc3_ulpi_busyloop(struct dwc3 *dwc, u8 addr, bool read) { + unsigned long ns = 5L * DWC3_ULPI_BASE_DELAY; unsigned int count = 1000; u32 reg; + if (addr >= ULPI_EXT_VENDOR_SPECIFIC) + ns += DWC3_ULPI_BASE_DELAY; + + if (read) + ns += DWC3_ULPI_BASE_DELAY; + while (count--) { + ndelay(ns); reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0)); if (reg & DWC3_GUSB2PHYACC_DONE) return 0; @@ -47,7 +59,7 @@ static int dwc3_ulpi_read(struct device *dev, u8 addr) reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr); dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg); - ret = dwc3_ulpi_busyloop(dwc); + ret = dwc3_ulpi_busyloop(dwc, addr, true); if (ret) return ret; @@ -71,7 +83,7 @@ static int dwc3_ulpi_write(struct device *dev, u8 addr, u8 val) reg |= DWC3_GUSB2PHYACC_WRITE | val; dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg); - return dwc3_ulpi_busyloop(dwc); + return dwc3_ulpi_busyloop(dwc, addr, false); } static const struct ulpi_ops dwc3_ulpi_ops = { -- 2.29.2