Bluetooth: btnxpuart: Add support for HCI coredump feature

This adds support for Bluetooth Coredump feature to BTNXPUART driver to
collect FW dumps on demand, or in case FW goes in a bad state.

To trigger manual FW dump, following command can be used:
echo 1 > /sys/class/bluetooth/hci0/device/coredump

Once FW dump is complete, it can be written to a file:
cat /sys/class/bluetooth/hci0/devcoredump/data > fw_dump

While FW dump is in progress, any HCI command will return -EBUSY.

After FW dump is complete, driver will give HCI_NXP_IND_RESET command
which soft-resets the chip, allowing FW re-download.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Author: NeerajSanjayKale

drivers/bluetooth/btnxpuart.c

@@ -31,6 +31,7 @@
 #define BTNXPUART_SERDEV_OPEN		4
 #define BTNXPUART_IR_IN_PROGRESS	5
 #define BTNXPUART_FW_DOWNLOAD_ABORT	6
+#define BTNXPUART_FW_DUMP_IN_PROGRESS	7
 
 /* NXP HW err codes */
 #define BTNXPUART_IR_HW_ERR		0xb0
@@ -106,6 +107,8 @@
 #define HCI_NXP_SET_OPER_SPEED	0xfc09
 /* Bluetooth vendor command: Independent Reset */
 #define HCI_NXP_IND_RESET	0xfcfc
+/* Bluetooth vendor command: Trigger FW dump */
+#define HCI_NXP_TRIGGER_DUMP	0xfe91
 
 /* Bluetooth Power State : Vendor cmd params */
 #define BT_PS_ENABLE			0x02
@@ -310,6 +313,16 @@ union nxp_v3_rx_timeout_nak_u {
 	u8 buf[6];
 };
 
+/* FW dump */
+#define NXP_FW_DUMP_SIZE	(1024 * 1000)
+
+struct nxp_fw_dump_hdr {
+	__le16 seq_num;
+	__le16 reserved;
+	__le16 buf_type;
+	__le16 buf_len;
+};
+
 static u8 crc8_table[CRC8_TABLE_SIZE];
 
 /* Default configurations */
@@ -774,6 +787,16 @@ static bool is_fw_downloading(struct btnxpuart_dev *nxpdev)
 	return test_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
 }
 
+static bool ind_reset_in_progress(struct btnxpuart_dev *nxpdev)
+{
+	return test_bit(BTNXPUART_IR_IN_PROGRESS, &nxpdev->tx_state);
+}
+
+static bool fw_dump_in_progress(struct btnxpuart_dev *nxpdev)
+{
+	return test_bit(BTNXPUART_FW_DUMP_IN_PROGRESS, &nxpdev->tx_state);
+}
+
 static bool process_boot_signature(struct btnxpuart_dev *nxpdev)
 {
 	if (test_bit(BTNXPUART_CHECK_BOOT_SIGNATURE, &nxpdev->tx_state)) {
@@ -1175,7 +1198,7 @@ static int nxp_set_baudrate_cmd(struct hci_dev *hdev, void *data)
 static int nxp_check_boot_sign(struct btnxpuart_dev *nxpdev)
 {
 	serdev_device_set_baudrate(nxpdev->serdev, HCI_NXP_PRI_BAUDRATE);
-	if (test_bit(BTNXPUART_IR_IN_PROGRESS, &nxpdev->tx_state))
+	if (ind_reset_in_progress(nxpdev))
 		serdev_device_set_flow_control(nxpdev->serdev, false);
 	else
 		serdev_device_set_flow_control(nxpdev->serdev, true);
@@ -1204,6 +1227,73 @@ static int nxp_set_ind_reset(struct hci_dev *hdev, void *data)
 	return hci_recv_frame(hdev, skb);
 }
 
+/* Firmware dump */
+static void nxp_coredump(struct hci_dev *hdev)
+{
+	struct sk_buff *skb;
+	u8 pcmd = 2;
+
+	skb = nxp_drv_send_cmd(hdev, HCI_NXP_TRIGGER_DUMP, 1, &pcmd);
+	if (!IS_ERR(skb))
+		kfree_skb(skb);
+}
+
+static void nxp_coredump_hdr(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	/* Nothing to be added in FW dump header */
+}
+
+static int nxp_process_fw_dump(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	struct hci_acl_hdr *acl_hdr = (struct hci_acl_hdr *)skb_pull_data(skb,
+									  sizeof(*acl_hdr));
+	struct nxp_fw_dump_hdr *fw_dump_hdr = (struct nxp_fw_dump_hdr *)skb->data;
+	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
+	__u16 seq_num = __le16_to_cpu(fw_dump_hdr->seq_num);
+	__u16 buf_len = __le16_to_cpu(fw_dump_hdr->buf_len);
+	int err;
+
+	if (seq_num == 0x0001) {
+		if (test_and_set_bit(BTNXPUART_FW_DUMP_IN_PROGRESS, &nxpdev->tx_state)) {
+			bt_dev_err(hdev, "FW dump already in progress");
+			goto free_skb;
+		}
+		bt_dev_warn(hdev, "==== Start FW dump ===");
+		err = hci_devcd_init(hdev, NXP_FW_DUMP_SIZE);
+		if (err < 0)
+			goto free_skb;
+
+		schedule_delayed_work(&hdev->dump.dump_timeout,
+				      msecs_to_jiffies(20000));
+	}
+
+	err = hci_devcd_append(hdev, skb_clone(skb, GFP_ATOMIC));
+	if (err < 0)
+		goto free_skb;
+
+	if (buf_len == 0) {
+		bt_dev_warn(hdev, "==== FW dump complete ===");
+		clear_bit(BTNXPUART_FW_DUMP_IN_PROGRESS, &nxpdev->tx_state);
+		hci_devcd_complete(hdev);
+		nxp_set_ind_reset(hdev, NULL);
+	}
+
+free_skb:
+	kfree_skb(skb);
+	return 0;
+}
+
+static int nxp_recv_acl_pkt(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	__u16 handle = __le16_to_cpu(hci_acl_hdr(skb)->handle);
+
+	/* FW dump chunks are ACL packets with conn handle 0xfff */
+	if ((handle & 0x0FFF) == 0xFFF)
+		return nxp_process_fw_dump(hdev, skb);
+	else
+		return hci_recv_frame(hdev, skb);
+}
+
 /* NXP protocol */
 static int nxp_setup(struct hci_dev *hdev)
 {
@@ -1265,20 +1355,15 @@ static int nxp_shutdown(struct hci_dev *hdev)
 {
 	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
 	struct sk_buff *skb;
-	u8 *status;
 	u8 pcmd = 0;
 
-	if (test_bit(BTNXPUART_IR_IN_PROGRESS, &nxpdev->tx_state)) {
+	if (ind_reset_in_progress(nxpdev)) {
 		skb = nxp_drv_send_cmd(hdev, HCI_NXP_IND_RESET, 1, &pcmd);
-		if (IS_ERR(skb))
-			return PTR_ERR(skb);
-
-		status = skb_pull_data(skb, 1);
-		if (status) {
-			serdev_device_set_flow_control(nxpdev->serdev, false);
-			set_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
-		}
-		kfree_skb(skb);
+		serdev_device_set_flow_control(nxpdev->serdev, false);
+		set_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
+		/* HCI_NXP_IND_RESET command may not returns any response */
+		if (!IS_ERR(skb))
+			kfree_skb(skb);
 	} else if (nxpdev->current_baudrate != nxpdev->fw_init_baudrate) {
 		nxpdev->new_baudrate = nxpdev->fw_init_baudrate;
 		nxp_set_baudrate_cmd(hdev, NULL);
@@ -1298,6 +1383,16 @@ static bool nxp_wakeup(struct hci_dev *hdev)
 	return false;
 }
 
+static void nxp_reset(struct hci_dev *hdev)
+{
+	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
+
+	if (!ind_reset_in_progress(nxpdev) && !fw_dump_in_progress(nxpdev)) {
+		bt_dev_dbg(hdev, "CMD Timeout detected. Resetting.");
+		nxp_set_ind_reset(hdev, NULL);
+	}
+}
+
 static int btnxpuart_queue_skb(struct hci_dev *hdev, struct sk_buff *skb)
 {
 	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
@@ -1318,6 +1413,9 @@ static int nxp_enqueue(struct hci_dev *hdev, struct sk_buff *skb)
 	struct wakeup_cmd_payload wakeup_parm;
 	__le32 baudrate_parm;
 
+	if (fw_dump_in_progress(nxpdev))
+		return -EBUSY;
+
 	/* if vendor commands are received from user space (e.g. hcitool), update
 	 * driver flags accordingly and ask driver to re-send the command to FW.
 	 * In case the payload for any command does not match expected payload
@@ -1486,7 +1584,7 @@ static int btnxpuart_flush(struct hci_dev *hdev)
 }
 
 static const struct h4_recv_pkt nxp_recv_pkts[] = {
-	{ H4_RECV_ACL,          .recv = hci_recv_frame },
+	{ H4_RECV_ACL,          .recv = nxp_recv_acl_pkt },
 	{ H4_RECV_SCO,          .recv = hci_recv_frame },
 	{ H4_RECV_EVENT,        .recv = hci_recv_frame },
 	{ H4_RECV_ISO,		.recv = hci_recv_frame },
@@ -1508,11 +1606,13 @@ static size_t btnxpuart_receive_buf(struct serdev_device *serdev,
 	if (IS_ERR(nxpdev->rx_skb)) {
 		int err = PTR_ERR(nxpdev->rx_skb);
 		/* Safe to ignore out-of-sync bootloader signatures */
-		if (!is_fw_downloading(nxpdev))
+		if (!is_fw_downloading(nxpdev) &&
+		    !ind_reset_in_progress(nxpdev))
 			bt_dev_err(nxpdev->hdev, "Frame reassembly failed (%d)", err);
 		return count;
 	}
-	if (!is_fw_downloading(nxpdev))
+	if (!is_fw_downloading(nxpdev) &&
+	    !ind_reset_in_progress(nxpdev))
 		nxpdev->hdev->stat.byte_rx += count;
 	return count;
 }
@@ -1580,6 +1680,7 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 	hdev->hw_error = nxp_hw_err;
 	hdev->shutdown = nxp_shutdown;
 	hdev->wakeup = nxp_wakeup;
+	hdev->reset = nxp_reset;
 	SET_HCIDEV_DEV(hdev, &serdev->dev);
 
 	if (hci_register_dev(hdev) < 0) {
@@ -1590,6 +1691,8 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 	if (ps_setup(hdev))
 		goto probe_fail;
 
+	hci_devcd_register(hdev, nxp_coredump, nxp_coredump_hdr, NULL);
+
 	return 0;
 
 probe_fail:
@@ -1641,6 +1744,17 @@ static int nxp_serdev_resume(struct device *dev)
 }
 #endif
 
+#ifdef CONFIG_DEV_COREDUMP
+static void nxp_serdev_coredump(struct device *dev)
+{
+	struct btnxpuart_dev *nxpdev = dev_get_drvdata(dev);
+	struct hci_dev  *hdev = nxpdev->hdev;
+
+	if (hdev->dump.coredump)
+		hdev->dump.coredump(hdev);
+}
+#endif
+
 static struct btnxpuart_data w8987_data __maybe_unused = {
 	.helper_fw_name = NULL,
 	.fw_name = FIRMWARE_W8987,
@@ -1671,6 +1785,9 @@ static struct serdev_device_driver nxp_serdev_driver = {
 		.name = "btnxpuart",
 		.of_match_table = of_match_ptr(nxpuart_of_match_table),
 		.pm = &nxp_pm_ops,
+#ifdef CONFIG_DEV_COREDUMP
+		.coredump = nxp_serdev_coredump,
+#endif
 	},
 };