From patchwork Sat Apr 10 00:47:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thinh Nguyen X-Patchwork-Id: 12195257 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 99E47C433B4 for ; Sat, 10 Apr 2021 00:47:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D66B6113A for ; Sat, 10 Apr 2021 00:47:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235319AbhDJArX (ORCPT ); Fri, 9 Apr 2021 20:47:23 -0400 Received: from smtprelay-out1.synopsys.com ([149.117.73.133]:39328 "EHLO smtprelay-out1.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235312AbhDJArW (ORCPT ); Fri, 9 Apr 2021 20:47:22 -0400 Received: from mailhost.synopsys.com (sv2-mailhost2.synopsys.com [10.205.2.134]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by smtprelay-out1.synopsys.com (Postfix) with ESMTPS id 02EA3401F1; Sat, 10 Apr 2021 00:47:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synopsys.com; s=mail; t=1618015629; bh=boOwoNo4+Zfzi026H2CCOo49+BR7HecMuFsdKCIS/WI=; h=Date:In-Reply-To:References:From:Subject:To:Cc:From; b=b1gr4tGTZjvX6QsbhcAjZUZ6hGowogUl593zw5fSk5Y1JLmd3eDfyN9RJGKsMwv6D CEPbMu1zAjW3klBER8GGoaioRI83R/Fi+0aKxDLXLQ7n2QrFE5OH7JIgtpcgq0VLhX A7GXdyvh8cr4HT2WK3JxYn5i4letqMLBreG/BuR451NExkginAOCHIkT7PcfiMPRwn k1IZdkZgVFhySbpg7k8luCHd8Lm3NSH4VSW086Y3Kau+DTNjEpoXbNWXC4abtpY7+i bWHV6pfVARPRlsJYv/cSu/f3EUhG9w3DxZmRTjE+HKqqkHIcViPyL3UQpkEPJ/9kp5 oD3SvxsX2ZL9Q== Received: from lab-vbox (unknown [10.205.130.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mailhost.synopsys.com (Postfix) with ESMTPSA id CD5C9A0096; Sat, 10 Apr 2021 00:47:07 +0000 (UTC) Received: by lab-vbox (sSMTP sendmail emulation); Fri, 09 Apr 2021 17:47:07 -0700 Date: Fri, 09 Apr 2021 17:47:07 -0700 Message-Id: In-Reply-To: References: X-SNPS-Relay: synopsys.com From: Thinh Nguyen Subject: [PATCH v2 4/7] usb: xhci: Workaround undercalculated BW for fullspeed BI To: Felipe Balbi , Greg Kroah-Hartman , Thinh.Nguyen@synopsys.com, linux-usb@vger.kernel.org, Mathias Nyman Cc: John Youn Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org DWC_usb31 host version 1.90a and prior undercalculates the bandwidth available for interrupt endpoints. The controller will return bandwidth error on config endpoint commands if there are already 6 or more fullspeed interrupt endpoints with bInterval of 4 (or 4ms) associated with a single fullspeed bus instance (BI). To workaround this, configure and use the endpoint at a shorter interrupt interval. Lower the ep_ctx interval from 5 to 4 (or 2ms) for interrupt endpoints of the fullspeed BI. Note: we have not observed functional impact to the fullspeed devices by lowering the interrupt service interval (at least for a few devices that we tested). To simplify the workaround, let's just check and apply the workaround if the endpoint is a fullspeed interrupt endpoint with interval of 4ms and if the top parent device is also operating in fullspeed (i.e. associated with fullspeed BI). Signed-off-by: Thinh Nguyen --- Changes in v2: - None Note: Checkpatch will give a warning below for getting top_dev: WARNING: suspect code indent for conditional statements Since this logic is done everywhere else in the driver, I'm keeping it consistent here. drivers/usb/host/xhci-mem.c | 23 +++++++++++++++++++++++ include/linux/usb/xhci-quirks.h | 1 + 2 files changed, 24 insertions(+) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 1053b43008e4..e01d0ddb012a 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -1463,6 +1463,29 @@ int xhci_endpoint_init(struct xhci_hcd *xhci, } } + /* + * Check for undercalculated bandwidth quirk for interrupt endpoints + * associated with fullspeed BI. + */ + if ((xhci->quirks & XHCI_LIMIT_FS_BI_INTR_EP) && + usb_endpoint_xfer_int(&ep->desc) && + udev->speed == USB_SPEED_FULL && + interval == 5) { + struct usb_device *top_dev; + + for (top_dev = udev; + top_dev->parent && top_dev->parent->parent; + top_dev = top_dev->parent) + /* Found device below root hub */; + + /* + * If the top device is operating at fullspeed, then the + * controller is using fullspeed BI for this device. + */ + if (top_dev->speed == USB_SPEED_FULL) + interval = 4; + } + mult = xhci_get_endpoint_mult(udev, ep); max_packet = usb_endpoint_maxp(&ep->desc); max_burst = xhci_get_endpoint_max_burst(udev, ep); diff --git a/include/linux/usb/xhci-quirks.h b/include/linux/usb/xhci-quirks.h index 65bb62d3d31d..5bedf5a25f7a 100644 --- a/include/linux/usb/xhci-quirks.h +++ b/include/linux/usb/xhci-quirks.h @@ -59,5 +59,6 @@ #define XHCI_SG_TRB_CACHE_SIZE_QUIRK BIT_ULL(39) #define XHCI_NO_SOFT_RETRY BIT_ULL(40) #define XHCI_ISOC_BLOCKED_DISCONNECT BIT_ULL(41) +#define XHCI_LIMIT_FS_BI_INTR_EP BIT_ULL(42) #endif /* __LINUX_USB_XHCI_QUIRKS_H */