linux-kernel - [PATCH v4 1/2] soc: qcom: smem: Register gunyah watchdog device

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20251031-gunyah_watchdog-v4-1-7abb1ee11315@oss.qualcomm.com>
Date: Fri, 31 Oct 2025 10:18:13 +0000
From: Hrishabh Rajput via B4 Relay <devnull+hrishabh.rajput.oss.qualcomm.com@...nel.org>
To: Bjorn Andersson <andersson@...nel.org>, 
 Konrad Dybcio <konradybcio@...nel.org>, 
 Wim Van Sebroeck <wim@...ux-watchdog.org>, 
 Guenter Roeck <linux@...ck-us.net>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, linux-watchdog@...r.kernel.org, 
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Pavan Kondeti <pavan.kondeti@....qualcomm.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, 
 Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>, 
 Hrishabh Rajput <hrishabh.rajput@....qualcomm.com>
Subject: [PATCH v4 1/2] soc: qcom: smem: Register gunyah watchdog device

From: Hrishabh Rajput <hrishabh.rajput@....qualcomm.com>

To restrict gunyah watchdog initialization to Qualcomm platforms,
register the watchdog device in the SMEM driver.

When Gunyah is not present or Gunyah emulates MMIO-based
watchdog, we expect Qualcomm watchdog or ARM SBSA watchdog device to be
present in the devicetree. If none of these device nodes are detected,
we register the SMC-based Gunyah watchdog device.

Signed-off-by: Hrishabh Rajput <hrishabh.rajput@....qualcomm.com>
---
 drivers/soc/qcom/smem.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
index cf425930539e..40e4749fab02 100644
--- a/drivers/soc/qcom/smem.c
+++ b/drivers/soc/qcom/smem.c
@@ -1118,6 +1118,34 @@ static int qcom_smem_resolve_mem(struct qcom_smem *smem, const char *name,
 	return 0;
 }
 
+static int register_gunyah_wdt_device(void)
+{
+	struct platform_device *gunyah_wdt_dev;
+	struct device_node *np;
+
+	/*
+	 * When Gunyah is not present or Gunyah is emulating a memory-mapped
+	 * watchdog, either of Qualcomm watchdog or ARM SBSA watchdog will be
+	 * present. Skip initialization of SMC-based Gunyah watchdog if that is
+	 * the case.
+	 */
+	np = of_find_compatible_node(NULL, NULL, "qcom,kpss-wdt");
+	if (np) {
+		of_node_put(np);
+		return 0;
+	}
+
+	np = of_find_compatible_node(NULL, NULL, "arm,sbsa-gwdt");
+	if (np) {
+		of_node_put(np);
+		return 0;
+	}
+
+	gunyah_wdt_dev = platform_device_register_simple("gunyah-wdt", -1,
+							 NULL, 0);
+	return PTR_ERR_OR_ZERO(gunyah_wdt_dev);
+}
+
 static int qcom_smem_probe(struct platform_device *pdev)
 {
 	struct smem_header *header;
@@ -1236,11 +1264,20 @@ static int qcom_smem_probe(struct platform_device *pdev)
 	if (IS_ERR(smem->socinfo))
 		dev_dbg(&pdev->dev, "failed to register socinfo device\n");
 
+	ret = register_gunyah_wdt_device();
+	if (ret)
+		dev_dbg(&pdev->dev, "failed to register watchdog device\n");
+
 	return 0;
 }
 
 static void qcom_smem_remove(struct platform_device *pdev)
 {
+	/*
+	 * Gunyah watchdog is intended to be a persistent module. Hence, the
+	 * watchdog device is not unregistered.
+	 */
+
 	platform_device_unregister(__smem->socinfo);
 
 	hwspin_lock_free(__smem->hwlock);

-- 
2.43.0