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Date:   Mon, 27 Mar 2023 18:18:55 -0700
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Subject: [PATCH v9 2/4] Bluetooth: Add vhci devcoredump support
From:   Manish Mandlik <mmandlik@google.com>
To:     marcel@holtmann.org, luiz.dentz@gmail.com
Cc:     chromeos-bluetooth-upstreaming@chromium.org,
        linux-bluetooth@vger.kernel.org,
        Manish Mandlik <mmandlik@google.com>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Add devcoredump support for vhci that creates forcce_devcoredump debugfs
entry. This is used for mgmt-tester tests.

Signed-off-by: Manish Mandlik <mmandlik@google.com>
---

Changes in v9:
- Rename hci_devcoredump_*() to hci_devcd_*()

Changes in v8:
- Update vhci_coredump_hdr() to use skb

Changes in v7:
- New patch in the series

 drivers/bluetooth/Kconfig    |  1 +
 drivers/bluetooth/hci_vhci.c | 64 ++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
index 5a1a7bec3c42..7bc7a765ad69 100644
--- a/drivers/bluetooth/Kconfig
+++ b/drivers/bluetooth/Kconfig
@@ -363,6 +363,7 @@ config BT_HCIBLUECARD
 
 config BT_HCIVHCI
 	tristate "HCI VHCI (Virtual HCI device) driver"
+	select WANT_DEV_COREDUMP
 	help
 	  Bluetooth Virtual HCI device driver.
 	  This driver is required if you want to use HCI Emulation software.
diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
index c443c3b0a4da..a265dcaf8275 100644
--- a/drivers/bluetooth/hci_vhci.c
+++ b/drivers/bluetooth/hci_vhci.c
@@ -278,6 +278,67 @@ static int vhci_setup(struct hci_dev *hdev)
 	return 0;
 }
 
+static void vhci_coredump(struct hci_dev *hdev)
+{
+	/* No need to do anything */
+}
+
+static void vhci_coredump_hdr(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	char buf[80];
+
+	snprintf(buf, sizeof(buf), "Controller Name: vhci_ctrl\n");
+	skb_put_data(skb, buf, strlen(buf));
+
+	snprintf(buf, sizeof(buf), "Firmware Version: vhci_fw\n");
+	skb_put_data(skb, buf, strlen(buf));
+
+	snprintf(buf, sizeof(buf), "Driver: vhci_drv\n");
+	skb_put_data(skb, buf, strlen(buf));
+
+	snprintf(buf, sizeof(buf), "Vendor: vhci\n");
+	skb_put_data(skb, buf, strlen(buf));
+}
+
+static ssize_t force_devcoredump_write(struct file *file,
+				       const char __user *user_buf,
+				       size_t count, loff_t *ppos)
+{
+	struct vhci_data *data = file->private_data;
+	struct hci_dev *hdev = data->hdev;
+	struct sk_buff *skb = NULL;
+	char buf[512];
+	int ret;
+
+	ret = simple_write_to_buffer(&buf, sizeof(buf), ppos, user_buf, count);
+	if (ret < count)
+		return ret;
+
+	skb = alloc_skb(count, GFP_ATOMIC);
+	if (!skb)
+		return -ENOMEM;
+	skb_put_data(skb, &buf, count);
+
+	hci_devcd_register(hdev, vhci_coredump, vhci_coredump_hdr, NULL);
+
+	ret = hci_devcd_init(hdev, skb->len);
+	if (ret) {
+		BT_ERR("Failed to generate devcoredump");
+		kfree_skb(skb);
+		return ret;
+	}
+
+	hci_devcd_append(hdev, skb);
+	hci_devcd_complete(hdev);
+
+	return count;
+}
+
+static const struct file_operations force_devcoredump_fops = {
+	.open		= simple_open,
+	.write		= force_devcoredump_write,
+};
+
 static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
 {
 	struct hci_dev *hdev;
@@ -355,6 +416,9 @@ static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
 		debugfs_create_file("aosp_capable", 0644, hdev->debugfs, data,
 				    &aosp_capable_fops);
 
+	debugfs_create_file("force_devcoredump", 0644, hdev->debugfs, data,
+			    &force_devcoredump_fops);
+
 	hci_skb_pkt_type(skb) = HCI_VENDOR_PKT;
 
 	skb_put_u8(skb, 0xff);
-- 
2.40.0.348.gf938b09366-goog