linux-kernel - [PATCH] Bluetooth: Allow reset via sysfs

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Message-ID: <20250103112019.1.I8342291b757b20cd4cdbbfe658dc58ed5df46565@changeid>
Date: Fri,  3 Jan 2025 11:20:20 +0800
From: Hsin-chen Chuang <chharry@...omium.org>
To: linux-bluetooth@...r.kernel.org,
	luiz.dentz@...il.com
Cc: chromeos-bluetooth-upstreaming@...omium.org,
	Hsin-chen Chuang <chharry@...omium.org>,
	Johan Hedberg <johan.hedberg@...il.com>,
	Marcel Holtmann <marcel@...tmann.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] Bluetooth: Allow reset via sysfs

Allow sysfs to trigger reset via the cmd_timeout function in hci device.
This is required to recover devices that are not responsive from
userspace.

Also remove the cmd timeout count in btusb since we only ever allow one
command in flight at a time. We should always reset after a single
command times out.

Signed-off-by: Hsin-chen Chuang <chharry@...omium.org>
---
This commit has been tested on a Chromebook by running
`echo 1 > /sys/class/bluetooth/hci0/reset`

 drivers/bluetooth/btusb.c | 10 ----------
 net/bluetooth/hci_sysfs.c | 19 +++++++++++++++++++
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 279fe6c115fac..a4810c77fa0da 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -879,7 +879,6 @@ struct btusb_data {
 	int (*disconnect)(struct hci_dev *hdev);
 
 	int oob_wake_irq;   /* irq for out-of-band wake-on-bt */
-	unsigned cmd_timeout_cnt;
 
 	struct qca_dump_info qca_dump;
 };
@@ -912,9 +911,6 @@ static void btusb_intel_cmd_timeout(struct hci_dev *hdev)
 	struct gpio_desc *reset_gpio = data->reset_gpio;
 	struct btintel_data *intel_data = hci_get_priv(hdev);
 
-	if (++data->cmd_timeout_cnt < 5)
-		return;
-
 	if (intel_data->acpi_reset_method) {
 		if (test_and_set_bit(INTEL_ACPI_RESET_ACTIVE, intel_data->flags)) {
 			bt_dev_err(hdev, "acpi: last reset failed ? Not resetting again");
@@ -997,9 +993,6 @@ static void btusb_rtl_cmd_timeout(struct hci_dev *hdev)
 
 	btusb_rtl_alloc_devcoredump(hdev, &hdr, NULL, 0);
 
-	if (++data->cmd_timeout_cnt < 5)
-		return;
-
 	if (!reset_gpio) {
 		btusb_reset(hdev);
 		return;
@@ -1044,9 +1037,6 @@ static void btusb_qca_cmd_timeout(struct hci_dev *hdev)
 		return;
 	}
 
-	if (++data->cmd_timeout_cnt < 5)
-		return;
-
 	if (reset_gpio) {
 		bt_dev_err(hdev, "Reset qca device via bt_en gpio");
 
diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 4b54dbbf0729a..7bf2b10b0a7cf 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -90,9 +90,28 @@ static void bt_host_release(struct device *dev)
 	module_put(THIS_MODULE);
 }
 
+static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	struct hci_dev *hdev = to_hci_dev(dev);
+
+	if (hdev->cmd_timeout)
+		hdev->cmd_timeout(hdev);
+
+	return count;
+}
+static DEVICE_ATTR_WO(reset);
+
+static struct attribute *bt_host_attrs[] = {
+	&dev_attr_reset.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(bt_host);
+
 static const struct device_type bt_host = {
 	.name    = "host",
 	.release = bt_host_release,
+	.groups = bt_host_groups,
 };
 
 void hci_init_sysfs(struct hci_dev *hdev)
-- 
2.47.1.613.gc27f4b7a9f-goog