From nobody Mon Sep 28 08:46:17 2026 Received: from mailgw02.mediatek.com (unknown [210.61.82.184]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B4A3B427FA2; Mon, 24 Aug 2026 13:29:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.61.82.184 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787578167; cv=none; b=JetwRuK7t6y6f1d3ksSD5nIWyi0BmUkt4QVwpZwTwHMulwXk0M1wYbZwNsXjjrVXaG4beElK3zOD3DKBsaLzFtAfUzJfryYdc+3hZhwxZJG6fWFJj+D8BvCrsu4f7C7KchlzhMngDzqOacPaWPIfwmz+sv+L3g3hiA3lmumTtJ4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787578167; c=relaxed/simple; bh=NHxuHgifUwMyVLzLq9xZAuvMLVvUL8E1WVhrwz3XoPQ=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=Yy77wPlDJK69UWs9CTZE0XvNhqICWxOZ6F29Il4yYpPwSgchdxg3EINXDMwFzPYbdTIwCCdBVWvnYLN7/kmWQxTmxCJUI15+CvdWruiDhxFtnVV5uM1i56XYjJRyij+6viXHmAyf3swxmWUJqDceKQYwaSgH569O9e1dpCFji1Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mediatek.com; spf=pass smtp.mailfrom=mediatek.com; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b=oMv/hnk9; arc=none smtp.client-ip=210.61.82.184 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mediatek.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mediatek.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b="oMv/hnk9" X-UUID: ce9072ae9fbf11f18dc8c9802ae25ab1-20260824 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:Content-Transfer-Encoding:MIME-Version:Message-ID:Date:Subject:CC:To:From; bh=AXV7791+lKEuxikXvEafEqUKInZMtNVXGmlQ9vNTOV0=; b=oMv/hnk94PcdcK0MXFlIX4CaUFAdM2dqrdvHA7guWMyRCwzpIPz0LYKgdwB2TJdFc+E2TKZsRebs3NGy4Hx7gtnKf4m/GI2oZCdFhsa4uKaI8TdqIr9YlfcsJfk1Hr2qP9yutmojIh6pFDgngVT1P+g9iK1KsN9i8gsIluUWwcs=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.19,REQID:5d32ca03-016a-4e1a-ac85-c09b25511271,IP:0,U RL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION: release,TS:0 X-CID-META: VersionHash:7db8b62,CLOUDID:9b719bad-201d-4c73-b99c-08a8ae797a27,B ulkID:nil,BulkQuantity:0,SF:102|136|836|865|888|898,TC:-5,Content:0|15|50| 99,EDM:-3|-100,IP:nil,URL:0,File:130,RT:0,Bulk:nil,QS:nil,BEC:-1,COL:0,OSI :0,OSA:0,AV:0,LES:1,SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0,ARC:0 X-CID-BVR: 2,SSN|SDN X-CID-BAS: 2,SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: ce9072ae9fbf11f18dc8c9802ae25ab1-20260824 Received: from mtkmbs10n1.mediatek.inc [(172.21.101.34)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1349857401; Mon, 24 Aug 2026 21:29:17 +0800 Received: from mtkmbs13n2.mediatek.inc (172.21.101.108) by mtkmbs10n1.mediatek.inc (172.21.101.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.29; Mon, 24 Aug 2026 21:29:16 +0800 Received: from gcnsap21.gcn.mediatek.inc (10.17.81.22) by mtkmbs13n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.2562.29 via Frontend Transport; Mon, 24 Aug 2026 21:29:16 +0800 From: Wanming Gao To: Wim Van Sebroeck , Guenter Roeck , Matthias Brugger , AngeloGioacchino Del Regno CC: , , , , , , , Subject: [PATCH] watchdog: mediatek: Enable pretimeout support Date: Mon, 24 Aug 2026 21:29:12 +0800 Message-ID: <20260824132914.2662346-1-wanming.gao@mediatek.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The watchdog pretimeout interrupt needs to be deasserted after the hardware pretimeout event is received. Add IRQ level control handling to the MediaTek watchdog interrupt handler so the interrupt is cleared before notifying the watchdog core. Serialize all WDT_MODE read-modify-write operations using the existing watchdog spinlock. Initialize the lock before registering the interrupt handler and hold it across the complete 70us IRQ level toggle sequence. This prevents concurrent watchdog start, stop, or pretimeout updates from overwriting the temporary IRQ level state and disrupting the deassert pulse. This avoids leaving the watchdog pretimeout interrupt asserted, prevents a potential interrupt storm, and allows the kernel to handle the pretimeout event properly before the final watchdog reset. Test: Boot ok, trigger watchdog pretimeout case and verify the pretimeout interrupt is received and handled before watchdog reset. Signed-off-by: Wanming Gao --- drivers/watchdog/mtk_wdt.c | 59 +++++++++++++++++++++++++++++++++++--- 1 file changed, 55 insertions(+), 4 deletions(-) diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c index d9c30e4c80e3..17176bee9d38 100644 --- a/drivers/watchdog/mtk_wdt.c +++ b/drivers/watchdog/mtk_wdt.c @@ -35,6 +35,7 @@ #define WDT_MAX_TIMEOUT 31 #define WDT_MIN_TIMEOUT 2 #define WDT_LENGTH_TIMEOUT(n) ((n) << 5) +#define WDT_IRQ_LEVEL_SYNC_US 70 =20 #define WDT_LENGTH 0x04 #define WDT_LENGTH_KEY 0x8 @@ -49,6 +50,7 @@ #define WDT_MODE_EXRST_EN (1 << 2) #define WDT_MODE_IRQ_EN (1 << 3) #define WDT_MODE_AUTO_START (1 << 4) +#define WDT_MODE_IRQ_LEVEL_EN (1 << 5) #define WDT_MODE_DUAL_EN (1 << 6) #define WDT_MODE_CNT_SEL (1 << 8) #define WDT_MODE_KEY 0x22000000 @@ -72,7 +74,7 @@ static unsigned int timeout; struct mtk_wdt_dev { struct watchdog_device wdt_dev; void __iomem *wdt_base; - spinlock_t lock; /* protects WDT_SWSYSRST reg */ + spinlock_t lock; /* protects WDT_MODE and WDT_SWSYSRST reg */ struct reset_controller_dev rcdev; bool disable_wdt_extrst; bool reset_by_toprgu; @@ -212,8 +214,6 @@ static int toprgu_register_reset_controller(struct plat= form_device *pdev, int ret; struct mtk_wdt_dev *mtk_wdt =3D platform_get_drvdata(pdev); =20 - spin_lock_init(&mtk_wdt->lock); - mtk_wdt->rcdev.owner =3D THIS_MODULE; mtk_wdt->rcdev.nr_resets =3D rst_num; mtk_wdt->rcdev.ops =3D &toprgu_reset_ops; @@ -230,14 +230,17 @@ static int mtk_wdt_restart(struct watchdog_device *wd= t_dev, { struct mtk_wdt_dev *mtk_wdt =3D watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base; + unsigned long flags; u32 reg; =20 wdt_base =3D mtk_wdt->wdt_base; =20 /* Enable reset in order to issue a system reset instead of an IRQ */ + spin_lock_irqsave(&mtk_wdt->lock, flags); reg =3D readl(wdt_base + WDT_MODE); reg &=3D ~WDT_MODE_IRQ_EN; writel(reg | WDT_MODE_KEY, wdt_base + WDT_MODE); + spin_unlock_irqrestore(&mtk_wdt->lock, flags); =20 while (1) { writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST); @@ -302,12 +305,15 @@ static int mtk_wdt_stop(struct watchdog_device *wdt_d= ev) { struct mtk_wdt_dev *mtk_wdt =3D watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base =3D mtk_wdt->wdt_base; + unsigned long flags; u32 reg; =20 + spin_lock_irqsave(&mtk_wdt->lock, flags); reg =3D readl(wdt_base + WDT_MODE); reg &=3D ~WDT_MODE_EN; reg |=3D WDT_MODE_KEY; iowrite32(reg, wdt_base + WDT_MODE); + spin_unlock_irqrestore(&mtk_wdt->lock, flags); =20 return 0; } @@ -317,12 +323,14 @@ static int mtk_wdt_start(struct watchdog_device *wdt_= dev) u32 reg; struct mtk_wdt_dev *mtk_wdt =3D watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base =3D mtk_wdt->wdt_base; + unsigned long flags; int ret; =20 ret =3D mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout); if (ret < 0) return ret; =20 + spin_lock_irqsave(&mtk_wdt->lock, flags); reg =3D ioread32(wdt_base + WDT_MODE); if (wdt_dev->pretimeout) reg |=3D (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN); @@ -334,6 +342,7 @@ static int mtk_wdt_start(struct watchdog_device *wdt_de= v) reg |=3D WDT_MODE_CNT_SEL; reg |=3D (WDT_MODE_EN | WDT_MODE_KEY); iowrite32(reg, wdt_base + WDT_MODE); + spin_unlock_irqrestore(&mtk_wdt->lock, flags); =20 return 0; } @@ -343,7 +352,11 @@ static int mtk_wdt_set_pretimeout(struct watchdog_devi= ce *wdd, { struct mtk_wdt_dev *mtk_wdt =3D watchdog_get_drvdata(wdd); void __iomem *wdt_base =3D mtk_wdt->wdt_base; - u32 reg =3D ioread32(wdt_base + WDT_MODE); + unsigned long flags; + u32 reg; + + spin_lock_irqsave(&mtk_wdt->lock, flags); + reg =3D ioread32(wdt_base + WDT_MODE); =20 if (timeout && !wdd->pretimeout) { wdd->pretimeout =3D wdd->timeout / 2; @@ -352,19 +365,55 @@ static int mtk_wdt_set_pretimeout(struct watchdog_dev= ice *wdd, wdd->pretimeout =3D 0; reg &=3D ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN); } else { + spin_unlock_irqrestore(&mtk_wdt->lock, flags); return 0; } =20 reg |=3D WDT_MODE_KEY; iowrite32(reg, wdt_base + WDT_MODE); + spin_unlock_irqrestore(&mtk_wdt->lock, flags); =20 return mtk_wdt_set_timeout(wdd, wdd->timeout); } =20 +static void mtk_wdt_deassert_irq(struct watchdog_device *wdd) +{ + struct mtk_wdt_dev *mtk_wdt =3D watchdog_get_drvdata(wdd); + void __iomem *wdt_base =3D mtk_wdt->wdt_base; + unsigned long flags; + u32 reg; + + spin_lock_irqsave(&mtk_wdt->lock, flags); + reg =3D ioread32(wdt_base + WDT_MODE); + + if (reg & WDT_MODE_IRQ_LEVEL_EN) { + reg &=3D ~WDT_MODE_IRQ_LEVEL_EN; + iowrite32(reg | WDT_MODE_KEY, wdt_base + WDT_MODE); + /* + * Wait for two 32KHz watchdog clock cycles so the + * hardware can latch the IRQ level change across the clock + * domain. + */ + udelay(WDT_IRQ_LEVEL_SYNC_US); + reg =3D ioread32(wdt_base + WDT_MODE); + reg |=3D WDT_MODE_IRQ_LEVEL_EN; + } else { + reg |=3D WDT_MODE_IRQ_LEVEL_EN; + iowrite32(reg | WDT_MODE_KEY, wdt_base + WDT_MODE); + udelay(WDT_IRQ_LEVEL_SYNC_US); + reg =3D ioread32(wdt_base + WDT_MODE); + reg &=3D ~WDT_MODE_IRQ_LEVEL_EN; + } + iowrite32(reg | WDT_MODE_KEY, wdt_base + WDT_MODE); + ioread32(wdt_base + WDT_MODE); + spin_unlock_irqrestore(&mtk_wdt->lock, flags); +} + static irqreturn_t mtk_wdt_isr(int irq, void *arg) { struct watchdog_device *wdd =3D arg; =20 + mtk_wdt_deassert_irq(wdd); watchdog_notify_pretimeout(wdd); =20 return IRQ_HANDLED; @@ -406,6 +455,8 @@ static int mtk_wdt_probe(struct platform_device *pdev) if (!mtk_wdt) return -ENOMEM; =20 + spin_lock_init(&mtk_wdt->lock); + platform_set_drvdata(pdev, mtk_wdt); =20 mtk_wdt->wdt_base =3D devm_platform_ioremap_resource(pdev, 0); --=20 2.45.2