From nobody Fri Dec 19 06:07:39 2025 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 891B31A256B for ; Sun, 16 Feb 2025 22:30:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739745010; cv=none; b=YkB5HtEBMgS5K0p0aWv1krgekEQRLohlenhw/KfCItJzdWsh74rk8Raw4CNGzAqdeIQVZwUG5UCZA06dU645xEsekA3lUM22qMG/lLLbTTaRQuDClnwobQ7NRyBpm44hKScivUbT+37jGClyYOiJ1YtADhaskGxXS/B7hbhKQbA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739745010; c=relaxed/simple; bh=LQHcicrNmgiAow4s/z1Kr2I6yAyQolTRZ7P8h/rJKd4=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=ZjoxtQVZetbPUVIL/r6rZtDPUNcQmSVfbINUhc6N6pLYuyLeaOPZN711CeFyxV02J6i5FMnAiwZH8XYiYA70ji0GUABBSBbGqqfqP0UiQacKx3M5Q0wh+WCKXM0azfP4BPnbj7A2zWm2ccUfl83WJ8n0wrbe90tWDDLeOLgenLg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--badhri.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=HTrTYdYz; arc=none smtp.client-ip=209.85.214.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--badhri.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="HTrTYdYz" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2210121ac27so33235685ad.1 for ; Sun, 16 Feb 2025 14:30:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1739745008; x=1740349808; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=PNKnjIND1cDqA5voAjCPjINYGDuyBQKKS2ATUZdV07o=; b=HTrTYdYzEwr6Bug/GQHjkynDKvBrMthfudcaGYNf2cgLVBGghkLjm3RUIzybtSsFnP Rzae/0w2bNONvGRBnky3GXepr50TkAnQ6pzqpr/m8TYOcyCjuJrkoNHK/tgQOUBy4Q3E pfgiVn2d9LacNCMx2/9j8LrbKbRQxTz7AkLZ6WA9SRwVCo8T9SQibtfqy1w6m1orImf0 yc8Cb3vt4nCVgHOCHGZk21YKHVIWMPtwvx1wD4j+Pm8fSS4Tn7FsuccDawsKmJPJXyLs ZxlZOmnp11fzZaAqQeUT2orFPtVMpybTL+uI1cZ1SsBkK23E+5lZZUlPtKehrR2tNWg0 DImQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739745008; x=1740349808; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=PNKnjIND1cDqA5voAjCPjINYGDuyBQKKS2ATUZdV07o=; b=ALirGiu+vx/A6uI/CX4p7dQghxAXY/w/AGf2+RCDHLnr5vrQ2bz8ASnNwDjCM/LFPY iKxLONI5MKL7xaQ9gdkeHgSdXWaiCdMPPaCBHez8H7cNt1kgp9YtdADXAB7tldUNMLel AaBS1atnqDU4HG0KHB8AyTot24dXVnHWBvKmdgLCbss/nfTeTO9b55dHUpvXx3SBhGxb 11JiZGbgs47d6GAE2k5bRCfFmNWnNe/xW+HVUzBsZ9azDG5mHMtraVAajF5+1DuG7Oi3 NZ+Qd/E+RImofdzZHBOoa9dpfNay3w02PVW+3P35ik0b3+xvHUiLzdwfWPVsSwgyHXiY wOHA== X-Forwarded-Encrypted: i=1; AJvYcCXPjoiJX9uXQjo2DNx7IyN0Ukz5gUd6eraN1dTkT4rV4aC+R1dyl9ikSif4cqXMDkydlEsM10tiiR9Xzi0=@vger.kernel.org X-Gm-Message-State: AOJu0YxjSRV1PzEynxGWxR17jFJSthbe/rGbqrpQaW/4UqWZIjKSvoPm vz+LVHXl3phnOTJ5V1TVNS5OfRhy3C5QwIk0HCIi+KNC7BGyTmH2FMmfdvW7Wznb00o/GkKqqHT sqw== X-Google-Smtp-Source: AGHT+IGimr17LrcrOJVFoDyG28j2uaoSa1qW7nDuBEqMagI93FDjZ+5itHfCRBNoeBZXHeX5KcpLhm/yiak= X-Received: from plkl5.prod.google.com ([2002:a17:902:d345:b0:21f:347:73a8]) (user=badhri job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:2f88:b0:220:c4f0:4ee7 with SMTP id d9443c01a7336-22103ef2039mr123034435ad.1.1739745007775; Sun, 16 Feb 2025 14:30:07 -0800 (PST) Date: Sun, 16 Feb 2025 22:30:02 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.48.1.601.g30ceb7b040-goog Message-ID: <20250216223003.3568039-1-badhri@google.com> Subject: [PATCH v3] usb: dwc3: gadget: Prevent irq storm when TH re-executes From: Badhri Jagan Sridharan To: Thinh.Nguyen@synopsys.com, gregkh@linuxfoundation.org, felipe.balbi@linux.intel.com Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, jameswei@google.com, Badhri Jagan Sridharan , stable@kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" While commit d325a1de49d6 ("usb: dwc3: gadget: Prevent losing events in event cache") makes sure that top half(TH) does not end up overwriting the cached events before processing them when the TH gets invoked more than one time, returning IRQ_HANDLED results in occasional irq storm where the TH hogs the CPU. The irq storm can be prevented by the flag before event handler busy is cleared. Default enable interrupt moderation in all versions which support them. ftrace event stub during dwc3 irq storm: irq/504_dwc3-1111 ( 1111) [000] .... 70.000866: irq_handler_exit: irq= =3D14 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000872: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000874: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000881: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000883: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000889: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000892: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000898: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000901: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000907: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000909: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000915: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000918: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000924: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000927: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000933: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000935: irq_handler_exit: irq= =3D504 ret=3Dhandled .... Cc: stable@kernel.org Suggested-by: Thinh Nguyen Fixes: d325a1de49d6 ("usb: dwc3: gadget: Prevent losing events in event cac= he") Signed-off-by: Badhri Jagan Sridharan Acked-by: Thinh Nguyen --- Changes since v2: * Consolidate logic for default enabling interrupt moderation as suggested by Thinh.Nguyen@ --- drivers/usb/dwc3/core.c | 16 ++++++---------- drivers/usb/dwc3/gadget.c | 10 +++++++--- 2 files changed, 13 insertions(+), 13 deletions(-) diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index dfa1b5fe48dc..2c472cb97f6c 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -1835,8 +1835,6 @@ static void dwc3_get_properties(struct dwc3 *dwc) dwc->tx_thr_num_pkt_prd =3D tx_thr_num_pkt_prd; dwc->tx_max_burst_prd =3D tx_max_burst_prd; =20 - dwc->imod_interval =3D 0; - dwc->tx_fifo_resize_max_num =3D tx_fifo_resize_max_num; } =20 @@ -1854,21 +1852,19 @@ static void dwc3_check_params(struct dwc3 *dwc) unsigned int hwparam_gen =3D DWC3_GHWPARAMS3_SSPHY_IFC(dwc->hwparams.hwparams3); =20 - /* Check for proper value of imod_interval */ - if (dwc->imod_interval && !dwc3_has_imod(dwc)) { - dev_warn(dwc->dev, "Interrupt moderation not supported\n"); - dwc->imod_interval =3D 0; - } - /* + * Enable IMOD for all supporting controllers. + * + * Particularly, DWC_usb3 v3.00a must enable this feature for + * the following reason: + * * Workaround for STAR 9000961433 which affects only version * 3.00a of the DWC_usb3 core. This prevents the controller * interrupt from being masked while handling events. IMOD * allows us to work around this issue. Enable it for the * affected version. */ - if (!dwc->imod_interval && - DWC3_VER_IS(DWC3, 300A)) + if (dwc3_has_imod((dwc))) dwc->imod_interval =3D 1; =20 /* Check the maximum_speed parameter */ diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index d27af65eb08a..fad115113d28 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -4467,14 +4467,18 @@ static irqreturn_t dwc3_process_event_buf(struct dw= c3_event_buffer *evt) dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0), DWC3_GEVNTSIZ_SIZE(evt->length)); =20 + evt->flags &=3D ~DWC3_EVENT_PENDING; + /* + * Add an explicit write memory barrier to make sure that the update of + * clearing DWC3_EVENT_PENDING is observed in dwc3_check_event_buf() + */ + wmb(); + if (dwc->imod_interval) { dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), DWC3_GEVNTCOUNT_EHB); dwc3_writel(dwc->regs, DWC3_DEV_IMOD(0), dwc->imod_interval); } =20 - /* Keep the clearing of DWC3_EVENT_PENDING at the end */ - evt->flags &=3D ~DWC3_EVENT_PENDING; - return ret; } =20 base-commit: 9682c35ff6ecd76d9462d4749b8b413d3e8e605e --=20 2.48.1.601.g30ceb7b040-goog