[v1,3/3] Bluetooth: NXP: Add protocol support for NXP Bluetooth chipsets

This adds a driver based on serdev driver for the NXP BT serial
protocol based on running H:4, which can enable the built-in
Bluetooth device inside a generic NXP BT chip.

This driver has Power Save feature that will put the chip into
sleep state whenever there is no activity for 2000ms, and will
be woken up when any activity is to be initiated.

This driver enables the power save feature by default by sending
the vendor specific commands to the chip during setup.

During setup, the driver is capable of reading the bootloader
signature unique to every chip, and downloading corresponding
FW file defined in a user-space config file. The firmware file
name can be defined in DTS file as well, in which case the
user-space config file will be ignored.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
---
 MAINTAINERS                |    7 +
 drivers/bluetooth/Kconfig  |   11 +
 drivers/bluetooth/Makefile |    1 +
 drivers/bluetooth/btnxp.c  | 1337 ++++++++++++++++++++++++++++++++++++
 drivers/bluetooth/btnxp.h  |  230 +++++++
 5 files changed, 1586 insertions(+)
 create mode 100644 drivers/bluetooth/btnxp.c
 create mode 100644 drivers/bluetooth/btnxp.h

On Tue, 24 Jan 2023, Neeraj Sanjay Kale wrote:

> This adds a driver based on serdev driver for the NXP BT serial
> protocol based on running H:4, which can enable the built-in
> Bluetooth device inside a generic NXP BT chip.
> 
> This driver has Power Save feature that will put the chip into
> sleep state whenever there is no activity for 2000ms, and will
> be woken up when any activity is to be initiated.
> 
> This driver enables the power save feature by default by sending
> the vendor specific commands to the chip during setup.
> 
> During setup, the driver is capable of reading the bootloader
> signature unique to every chip, and downloading corresponding
> FW file defined in a user-space config file. The firmware file
> name can be defined in DTS file as well, in which case the
> user-space config file will be ignored.
> 
> Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
> ---
>  MAINTAINERS                |    7 +
>  drivers/bluetooth/Kconfig  |   11 +
>  drivers/bluetooth/Makefile |    1 +
>  drivers/bluetooth/btnxp.c  | 1337 ++++++++++++++++++++++++++++++++++++
>  drivers/bluetooth/btnxp.h  |  230 +++++++
>  5 files changed, 1586 insertions(+)
>  create mode 100644 drivers/bluetooth/btnxp.c
>  create mode 100644 drivers/bluetooth/btnxp.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 32dd41574930..20bb9e6b44b5 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -22835,6 +22835,13 @@ L:	linux-mm@kvack.org
>  S:	Maintained
>  F:	mm/zswap.c
>  
> +NXP BLUETOOTH WIRELESS DRIVERS
> +M:	Amitkumar Karwar <amitkumar.karwar@nxp.com>
> +M:	Neeraj Kale <neeraj.sanjaykale@nxp.com>
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/net/bluetooth/nxp-bluetooth.yaml
> +F:	drivers/bluetooth/btnxp*
> +
>  THE REST
>  M:	Linus Torvalds <torvalds@linux-foundation.org>
>  L:	linux-kernel@vger.kernel.org
> diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
> index 5a1a7bec3c42..773b40d34b7b 100644
> --- a/drivers/bluetooth/Kconfig
> +++ b/drivers/bluetooth/Kconfig
> @@ -465,4 +465,15 @@ config BT_VIRTIO
>  	  Say Y here to compile support for HCI over Virtio into the
>  	  kernel or say M to compile as a module.
>  
> +config BT_NXPUART
> +	tristate "NXP protocol support"
> +	depends on SERIAL_DEV_BUS
> +	help
> +	  NXP is serial driver required for NXP Bluetooth
> +	  devices with UART interface.
> +
> +	  Say Y here to compile support for NXP Bluetooth UART device into
> +	  the kernel, or say M here to compile as a module.
> +
> +
>  endmenu
> diff --git a/drivers/bluetooth/Makefile b/drivers/bluetooth/Makefile
> index e0b261f24fc9..6c0e7fbe2297 100644
> --- a/drivers/bluetooth/Makefile
> +++ b/drivers/bluetooth/Makefile
> @@ -29,6 +29,7 @@ obj-$(CONFIG_BT_QCA)		+= btqca.o
>  obj-$(CONFIG_BT_MTK)		+= btmtk.o
>  
>  obj-$(CONFIG_BT_VIRTIO)		+= virtio_bt.o
> +obj-$(CONFIG_BT_NXPUART)	+= btnxp.o
>  
>  obj-$(CONFIG_BT_HCIUART_NOKIA)	+= hci_nokia.o
>  
> diff --git a/drivers/bluetooth/btnxp.c b/drivers/bluetooth/btnxp.c
> new file mode 100644
> index 000000000000..0066f778593a
> --- /dev/null
> +++ b/drivers/bluetooth/btnxp.c
> @@ -0,0 +1,1337 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + *
> + *  NXP Bluetooth driver
> + *  Copyright 2018-2023 NXP
> + *
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +
> +#include <linux/serdev.h>
> +#include <linux/of.h>
> +#include <linux/skbuff.h>
> +#include <asm/unaligned.h>
> +#include <linux/firmware.h>
> +#include <linux/string.h>
> +#include <linux/crc8.h>
> +
> +#include <net/bluetooth/bluetooth.h>
> +#include <net/bluetooth/hci_core.h>
> +
> +#include "btnxp.h"
> +#include "h4_recv.h"
> +
> +#define BTNXPUART_TX_STATE_ACTIVE	1
> +#define BTNXPUART_TX_STATE_WAKEUP	2
> +#define BTNXPUART_FW_DOWNLOADING	3
> +
> +static const struct chip_id_map_table chip_id_name_table[] = {
> +	{0xffff, "legacy_chip"},	/* for legacy bootloader chipsets w8987 and w8997 */
> +	{0x7201, "iw416"},
> +	{0x7601, "iw612"},
> +	{0x5c03, "w9098"},
> +};
> +
> +static u8 crc8_table[CRC8_TABLE_SIZE];
> +static unsigned long crc32_table[256];
> +static struct fw_params fw_mod_params[MAX_NO_OF_CHIPS_SUPPORT];
> +
> +/* NXP Power Save Feature */
> +int wakeupmode = WAKEUP_METHOD_BREAK;
> +int ps_mode = PS_MODE_ENABLE;
> +
> +static void ps_start_timer(struct btnxpuart_dev *nxpdev)
> +{
> +	struct ps_data *psdata = nxpdev->psdata;
> +
> +	if (!psdata)
> +		return;
> +
> +	if (psdata->cur_psmode ==  PS_MODE_ENABLE) {
> +		psdata->timer_on = 1;
> +		mod_timer(&psdata->ps_timer, jiffies + (psdata->interval * HZ) / 1000);
> +	}
> +}
> +
> +static void ps_cancel_timer(struct btnxpuart_dev *nxpdev)
> +{
> +	struct ps_data *psdata = nxpdev->psdata;
> +
> +	if (!psdata)
> +		return;
> +
> +	flush_scheduled_work();
> +	if (psdata->timer_on)
> +		del_timer(&psdata->ps_timer);
> +	kfree(psdata);
> +}
> +
> +static void ps_control(struct hci_dev *hdev, u8 ps_state)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	struct ps_data *psdata = nxpdev->psdata;
> +
> +	if (psdata->ps_state == ps_state)
> +		return;
> +
> +	switch (psdata->cur_wakeupmode) {
> +	case WAKEUP_METHOD_DTR:
> +		if (ps_state == PS_STATE_AWAKE)
> +			serdev_device_set_tiocm(nxpdev->serdev, TIOCM_DTR, 0);  /* DTR ON */
> +		else
> +			serdev_device_set_tiocm(nxpdev->serdev, 0, TIOCM_DTR);  /* DTR OFF */
> +		break;
> +	case WAKEUP_METHOD_BREAK:
> +	default:
> +		BT_INFO("Set UART break: %s", ps_state == PS_STATE_AWAKE ? "off" : "on");
> +		if (ps_state == PS_STATE_AWAKE)
> +			serdev_device_break_ctl(nxpdev->serdev, 0);	/* break OFF */
> +		else
> +			serdev_device_break_ctl(nxpdev->serdev, -1); /* break ON */
> +		break;
> +	}
> +	psdata->ps_state = ps_state;
> +
> +	if (ps_state == PS_STATE_AWAKE)
> +		btnxpuart_tx_wakeup(nxpdev);
> +}
> +
> +static void ps_work_func(struct work_struct *work)
> +{
> +	struct ps_data *data = container_of(work, struct ps_data, work);
> +
> +	if (data->ps_cmd == PS_CMD_ENTER_PS && data->cur_psmode == PS_MODE_ENABLE)
> +		ps_control(data->hdev, PS_STATE_SLEEP);
> +	else  if (data->ps_cmd == PS_CMD_EXIT_PS)
> +		ps_control(data->hdev, PS_STATE_AWAKE);
> +}
> +
> +static void ps_timeout_func(struct timer_list *t)
> +{
> +	struct ps_data *data = from_timer(data, t, ps_timer);
> +	struct hci_dev *hdev = data->hdev;
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +
> +	data->timer_on = 0;
> +	if (test_bit(BTNXPUART_TX_STATE_ACTIVE, &nxpdev->tx_state)) {
> +		ps_start_timer(nxpdev);
> +	} else {
> +		data->ps_cmd = PS_CMD_ENTER_PS;
> +		schedule_work(&data->work);
> +	}
> +}
> +
> +static int ps_init_work(struct hci_dev *hdev)
> +{
> +	struct ps_data *psdata = kzalloc(sizeof(*psdata), GFP_KERNEL);
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +
> +	if (!psdata) {
> +		BT_ERR("Can't allocate control structure for Power Save feature");
> +		return -ENOMEM;
> +	}
> +	nxpdev->psdata = psdata;
> +
> +	memset(psdata, 0, sizeof(*psdata));

Why memset to zero kzalloc'ed mem?

> +	psdata->interval = PS_DEFAULT_TIMEOUT_PERIOD;
> +	psdata->ps_state = PS_STATE_AWAKE;
> +	psdata->ps_mode = ps_mode;
> +	psdata->hdev = hdev;
> +
> +	switch (wakeupmode) {
> +	case WAKEUP_METHOD_DTR:
> +		psdata->wakeupmode =  WAKEUP_METHOD_DTR;
> +		break;
> +	case  WAKEUP_METHOD_BREAK:
> +	default:
> +		psdata->wakeupmode =  WAKEUP_METHOD_BREAK;
> +		break;
> +	}
> +
> +	psdata->cur_psmode = PS_MODE_DISABLE;
> +	psdata->cur_wakeupmode = WAKEUP_METHOD_INVALID;
> +	INIT_WORK(&psdata->work, ps_work_func);
> +
> +	return 0;
> +}
> +
> +static void ps_init_timer(struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	struct ps_data *psdata = nxpdev->psdata;
> +
> +	psdata->timer_on = 0;
> +	timer_setup(&psdata->ps_timer, ps_timeout_func, 0);
> +}
> +
> +static int ps_wakeup(struct btnxpuart_dev *nxpdev)
> +{
> +	struct ps_data *psdata = nxpdev->psdata;
> +	int ret = 1;
> +
> +	if (psdata->ps_state == PS_STATE_AWAKE)
> +		ret = 0;
> +	psdata->ps_cmd = PS_CMD_EXIT_PS;
> +	schedule_work(&psdata->work);
> +
> +	return ret;
> +}
> +
> +static int send_ps_cmd(struct hci_dev *hdev, void *data)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	struct ps_data *psdata = nxpdev->psdata;
> +	u8 pcmd;
> +	struct sk_buff *skb;
> +	u8 *status;
> +
> +	if (psdata->ps_mode ==  PS_MODE_ENABLE)
> +		pcmd = BT_PS_ENABLE;
> +	else
> +		pcmd = BT_PS_DISABLE;
> +
> +	psdata->driver_sent_cmd = true;	/* set flag to prevent re-sending command in nxp_enqueue */
> +	skb = __hci_cmd_sync(hdev, HCI_NXP_AUTO_SLEEP_MODE, 1, &pcmd, HCI_CMD_TIMEOUT);
> +	psdata->driver_sent_cmd = false;

A helper for these 3 lines?

> +	if (IS_ERR(skb)) {
> +		bt_dev_err(hdev, "Setting Power Save mode failed (%ld)",
> +			   PTR_ERR(skb));
> +		return PTR_ERR(skb);
> +	}
> +
> +	status = skb_pull_data(skb, 1);
> +
> +	if (status) {
> +		if (!*status)
> +			psdata->cur_psmode = psdata->ps_mode;
> +		else
> +			psdata->ps_mode = psdata->cur_psmode;
> +		if (psdata->cur_psmode == PS_MODE_ENABLE)
> +			ps_start_timer(nxpdev);
> +		else
> +			ps_wakeup(nxpdev);
> +		BT_INFO("Power Save mode response: status=%d, ps_mode=%d",
> +			*status, psdata->cur_psmode);
> +	}
> +	return 0;
> +}
> +
> +static int send_wakeup_method_cmd(struct hci_dev *hdev, void *data)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	struct ps_data *psdata = nxpdev->psdata;
> +	u8 pcmd[4];
> +	struct sk_buff *skb;
> +	u8 *status;
> +
> +	pcmd[0] = BT_HOST_WAKEUP_METHOD_NONE;
> +	pcmd[1] = BT_HOST_WAKEUP_DEFAULT_GPIO;
> +	switch (psdata->wakeupmode) {
> +	case WAKEUP_METHOD_DTR:
> +		pcmd[2] = BT_CTRL_WAKEUP_METHOD_DSR;
> +		break;
> +	case WAKEUP_METHOD_BREAK:
> +	default:
> +		pcmd[2] = BT_CTRL_WAKEUP_METHOD_BREAK;
> +		break;
> +	}
> +	pcmd[3] = 0xFF;
> +
> +	psdata->driver_sent_cmd = true;	/* set flag to prevent re-sending command in nxp_enqueue */
> +	skb = __hci_cmd_sync(hdev, HCI_NXP_WAKEUP_METHOD, 4, pcmd, HCI_CMD_TIMEOUT);
> +	psdata->driver_sent_cmd = false;
> +
> +	if (IS_ERR(skb)) {
> +		bt_dev_err(hdev, "Setting wake-up method failed (%ld)",
> +			   PTR_ERR(skb));
> +		return PTR_ERR(skb);
> +	}
> +
> +	status = skb_pull_data(skb, 1);
> +	if (status) {
> +		if (*status == 0)
> +			psdata->cur_wakeupmode = psdata->wakeupmode;
> +		else
> +			psdata->wakeupmode = psdata->cur_wakeupmode;
> +		BT_INFO("Set Wakeup Method response: status=%d, wakeupmode=%d",
> +			*status, psdata->cur_wakeupmode);
> +	}

Do you need to free the skb?

> +
> +	return 0;
> +}
> +
> +static int ps_init(struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	struct ps_data *psdata = nxpdev->psdata;
> +
> +	serdev_device_set_tiocm(nxpdev->serdev, TIOCM_RTS, 0); /* RTS ON */
> +
> +	switch (psdata->wakeupmode) {
> +	case WAKEUP_METHOD_DTR:
> +		serdev_device_set_tiocm(nxpdev->serdev, 0, TIOCM_DTR); /* DTR OFF */
> +		serdev_device_set_tiocm(nxpdev->serdev, TIOCM_DTR, 0); /* DTR ON */
> +		break;
> +	case WAKEUP_METHOD_BREAK:
> +	default:
> +		serdev_device_break_ctl(nxpdev->serdev, -1);	/* break ON */
> +		serdev_device_break_ctl(nxpdev->serdev, 0);		/* break OFF */

I'm not convinced these 5 comments really add any useful info.

> +		break;
> +	}
> +	if (!test_bit(HCI_RUNNING, &hdev->flags)) {
> +		BT_ERR("HCI_RUNNING is not set");
> +		return -EBUSY;
> +	}
> +	if (psdata->cur_wakeupmode != psdata->wakeupmode)
> +		hci_cmd_sync_queue(hdev, send_wakeup_method_cmd, NULL, NULL);
> +	if (psdata->cur_psmode != psdata->ps_mode)
> +		hci_cmd_sync_queue(hdev, send_ps_cmd, NULL, NULL);
> +
> +	return 0;
> +}
> +
> +/* NXP Firmware Download Feature */
> +static u16 nxp_get_chip_id_from_name(u8 *name_str)
> +{
> +	int map_table_size = sizeof(chip_id_name_table) / sizeof(struct chip_id_map_table);
> +	int i;
> +
> +	for (i = 0; i < map_table_size; i++) {

Isn't this just ARRAY_SIZE(chip_id_name_table)? use it directly here,
no need for the extra variable?

> +		if (!strcmp(chip_id_name_table[i].chip_name, name_str))
> +			return chip_id_name_table[i].chip_id;
> +	}
> +
> +	return 0;  /* invalid name_str */

Put such comment preferrably to function's comment if you want to note
things like this or create a properly named define for it.

> +}
> +
> +static int nxp_parse_conf_file(struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	const char *sptr;
> +	char *dptr, *label, *value;
> +	char line[100];
> +	int i = 0;
> +	int param_index = 0;
> +	int line_num = 1;
> +	int ret = 0;
> +	bool skipline = false;
> +	bool valid_param = false;

Reverse xmas-tree order would help while reading these.

> +
> +	memset(fw_mod_params, 0, sizeof(fw_mod_params));
> +	sptr = nxpdev->fw_config->data;
> +	dptr = line;
> +	for (i = 0; i < nxpdev->fw_config->size; i++) {
> +		/* if current line is a comment, ignore */
> +		if (sptr[i] == '#') {
> +			skipline = true;
> +			continue;
> +		}
> +		if (sptr[i] != '\n' && skipline)
> +			continue;
> +		/* ignore space <CR> and comma*/

Missing space.

> +		if (sptr[i] == ' ' || sptr[i] == '\r' || sptr[i] == ',')
> +			continue;
> +		/* select next fw_mod_params index */
> +		if (sptr[i] == '}') {
> +			if (!valid_param) {
> +				BT_ERR("Unexpected '}' on line %d", line_num);
> +				ret = -1;
> +				goto err;
> +			}
> +			param_index++;
> +			valid_param = false;
> +			continue;
> +		}
> +		if (sptr[i] == '\n') {
> +			line_num++;
> +			if (skipline) {
> +				skipline = false;
> +				continue;
> +			}
> +			*dptr = '\0';
> +			/* ignore empty lines */
> +			if (strlen(line) == 0)
> +				continue;
> +			dptr = line;
> +			label = strsep(&dptr, "=");
> +			value = strsep(&dptr, "=");
> +			if (label && value) {
> +				if (!strcmp(value, "{")) {
> +					valid_param = true;
> +					strncpy(fw_mod_params[param_index].chip_name,
> +						label, MAX_CHIP_NAME_LEN);
> +					fw_mod_params[param_index].chip_id =
> +								nxp_get_chip_id_from_name(label);
> +					if (fw_mod_params[param_index].chip_id == 0) {
> +						BT_ERR("Invalid label %s in %s", label,
> +							   BT_FW_CONF_FILE);
> +						ret = -1;
> +						goto err;
> +					}
> +				} else {
> +					if (!valid_param) {
> +						BT_ERR("Expecting a '{' on line %d", line_num - 1);
> +						ret = -1;
> +						goto err;
> +					}
> +					if (!strcmp(label, FW_NAME_TAG)) {
> +						strncpy(fw_mod_params[param_index].fw_name,
> +							value, MAX_FW_FILE_NAME_LEN);
> +					} else if (!strcmp(label, OPER_SPEED_TAG)) {
> +						ret = kstrtouint(value, 10,
> +						&fw_mod_params[param_index].oper_speed);
> +					} else if (!strcmp(label, FW_DL_PRI_BAUDRATE_TAG)) {
> +						ret = kstrtouint(value, 10,
> +						&fw_mod_params[param_index].fw_dnld_pri_baudrate);
> +					} else if (!strcmp(label, FW_DL_SEC_BAUDRATE_TAG)) {
> +						ret = kstrtouint(value, 10,
> +						&fw_mod_params[param_index].fw_dnld_sec_baudrate);
> +					} else if (!strcmp(label, FW_INIT_BAUDRATE)) {
> +						ret = kstrtouint(value, 10,
> +						&fw_mod_params[param_index].fw_init_baudrate);
> +					} else {
> +						BT_ERR("Unknown tag: %s", label);
> +						ret = -1;
> +						goto err;
> +					}

Your indent is way too deep here, refactor the line processing into
another function to make it readable?

Wouldn't something like sscanf() make it a bit simpler?

> +				}
> +			} else {
> +				BT_ERR("Invalid \"key\" = \"value\" pair at line: %d",
> +					   line_num - 1);
> +			}
> +			dptr = line;
> +		} else {
> +			*dptr = sptr[i];
> +			dptr++;

What prevents dptr becoming larger than the size allocated for line?

> +		}
> +	}
> +	/* '}' not found till the end of the file */
> +	if (valid_param) {
> +		BT_ERR("Expecting a '}' before the end of the file");
> +		ret = -1;
> +		goto err;
> +	}
> +err:
> +	return ret;
> +}
> +
> +static int nxp_load_fw_params_for_chip_id(u16 chip_id, struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	int i;
> +
> +	for (i = 0; i < MAX_NO_OF_CHIPS_SUPPORT; i++) {
> +		if (chip_id == fw_mod_params[i].chip_id) {

reverse if condition and use continue, and and you can lower indent for 
these:

> +			strncpy(nxpdev->fw_name, fw_mod_params[i].fw_name, MAX_FW_FILE_NAME_LEN);
> +			nxpdev->oper_speed = fw_mod_params[i].oper_speed;
> +			nxpdev->fw_dnld_pri_baudrate = fw_mod_params[i].fw_dnld_pri_baudrate;
> +			nxpdev->fw_dnld_sec_baudrate = fw_mod_params[i].fw_dnld_sec_baudrate;
> +			nxpdev->fw_init_baudrate = fw_mod_params[i].fw_init_baudrate;
> +			break;
> +		}
> +	}
> +	if (i == MAX_NO_OF_CHIPS_SUPPORT) {
> +		if (chip_id == 0xffff)
> +			BT_ERR("%s does not contain entry for 'legacy_chip'", BT_FW_CONF_FILE);
> +		else
> +			BT_ERR("Unsupported chip signature: %04X", chip_id);
> +		clear_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
> +		return -ENOENT;
> +	}
> +	return 0;
> +}
> +
> +static int nxp_download_firmware(struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	const struct btnxpuart_data *nxp_data = nxpdev->nxp_data;
> +	int err = 0;
> +
> +	nxpdev->fw_dnld_offset = 0;
> +	nxpdev->fw_sent_bytes = 0;
> +
> +	crc8_populate_msb(crc8_table, POLYNOMIAL8);
> +
> +	serdev_device_set_baudrate(nxpdev->serdev, nxp_data->fw_dnld_pri_baudrate);
> +	serdev_device_set_flow_control(nxpdev->serdev, 0);
> +	set_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
> +	nxpdev->current_baudrate = nxp_data->fw_dnld_pri_baudrate;
> +	nxpdev->fw_v3_offset_correction = 0;
> +
> +	/* Wait till FW is downloaded and CTS becomes low */
> +	init_waitqueue_head(&nxpdev->suspend_wait_q);
> +	err = wait_event_interruptible_timeout(nxpdev->suspend_wait_q,
> +			!test_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state),
> +			msecs_to_jiffies(60000));
> +	if (err == 0) {
> +		BT_ERR("FW Download Timeout.");
> +		return -ETIMEDOUT;
> +	}
> +
> +	err = serdev_device_wait_for_cts(nxpdev->serdev, 1, 60000);
> +	if (err < 0) {
> +		BT_ERR("CTS is still high. FW Download failed.");
> +		return err;
> +	}
> +	BT_INFO("CTS is low");
> +	release_firmware(nxpdev->fw);
> +
> +	/* Allow the downloaded FW to initialize */
> +	usleep_range(20000, 22000);
> +
> +	return 0;
> +}
> +
> +static int nxp_send_ack(u8 ack, struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	u8 ack_nak[2];
> +
> +	if (ack == NXP_ACK_V1 || ack == NXP_NAK_V1) {
> +		ack_nak[0] = ack;
> +		serdev_device_write_buf(nxpdev->serdev, ack_nak, 1);
> +	} else if (ack == NXP_ACK_V3) {
> +		ack_nak[0] = ack;
> +		ack_nak[1] = crc8(crc8_table, ack_nak, 1, 0xFF);
> +		serdev_device_write_buf(nxpdev->serdev, ack_nak, 2);
> +	}
> +	return 0;
> +}
> +
> +static void nxp_fw_dnld_gen_crc_table(void)
> +{
> +	int i, j;
> +	unsigned long crc_accum;
> +
> +	for (i = 0; i < 256; i++) {
> +		crc_accum = ((unsigned long)i << 24);
> +		for (j = 0;  j < 8;  j++) {
> +			if (crc_accum & 0x80000000L)
> +				crc_accum = (crc_accum << 1) ^ POLYNOMIAL32;
> +			else
> +				crc_accum = (crc_accum << 1);
> +		}
> +		crc32_table[i] = crc_accum;
> +	}
> +}
> +
> +static unsigned long nxp_fw_dnld_update_crc(unsigned long crc_accum,
> +										char *data_blk_ptr,
> +										int data_blk_size)
> +{
> +	unsigned long i, j;
> +
> +	for (j = 0; j < data_blk_size; j++) {
> +		i = ((unsigned long)(crc_accum >> 24) ^ *data_blk_ptr++) & 0xff;
> +		crc_accum = (crc_accum << 8) ^ crc32_table[i];
> +	}
> +	return crc_accum;
> +}
> +
> +static bool nxp_fw_change_baudrate(struct hci_dev *hdev, u16 req_len)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	static u8 nxp_cmd5_header[HDR_LEN] = {

It would be good to prefix HDR_LEN with something to make it more specific
to this use case.

> +							0x05, 0x00, 0x00, 0x00,
> +							0x00, 0x00, 0x00, 0x00,
> +							0x2c, 0x00, 0x00, 0x00,
> +							0x77, 0xdb, 0xfd, 0xe0};
> +	static u8 uart_config[60] = {0};

Is this some structure actually? You seem to be filling it always with
the same stuff in same order?

You probably need to handle byte-order properly too.

> +	u32 header_len = 0;
> +	u32 uart_config_len = 0;
> +	u32 mcr = MCR;
> +	u32 init = INIT;
> +	u32 icr = ICR;
> +	u32 fcr = FCR;
> +	u32 br_addr = CLKDIVADDR;
> +	u32 div_addr = UARTDIVADDR;
> +	u32 mcr_addr = UARTMCRADDR;
> +	u32 re_init_addr = UARTREINITADDR;
> +	u32 icr_addr = UARTICRADDR;
> +	u32 fcr_addr = UARTFCRADDR;
> +	u32 uart_div = 1;
> +	u32 uart_clk = 0x00C00000;
> +	u32 crc = 0;
> +	bool ret = false;
> +
> +	nxpdev->fw_v3_offset_correction += req_len;
> +
> +	if (req_len == HDR_LEN) {
> +		/* Create CMD5 payload */
> +		memcpy(uart_config + uart_config_len, &br_addr, sizeof(br_addr));
> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &uart_clk, sizeof(uart_clk));
> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &div_addr, 4);

Why only part use sizeof and this one doesn't but you should probably
convert struct and proper byte-order handling anyway so addressing this 
comment is likely irrelevant.

> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &uart_div, 4);
> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &mcr_addr, 4);
> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &mcr, 4);
> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &re_init_addr, 4);
> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &init, 4);
> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &icr_addr, 4);
> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &icr, 4);
> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &fcr_addr, 4);
> +		uart_config_len += 4;
> +		memcpy(uart_config + uart_config_len, &fcr, 4);
> +		uart_config_len += 4;
> +		header_len = uart_config_len + 4;
> +
> +		nxp_fw_dnld_gen_crc_table();
> +
> +		/* Calculate CRC for CMD5 Header */
> +		memcpy(nxp_cmd5_header + 8, &header_len, sizeof(header_len));
> +		crc = (u32)nxp_fw_dnld_update_crc(0UL, nxp_cmd5_header, 12);
> +		crc = (u32)SWAPL(crc);
> +		memcpy(nxp_cmd5_header + 12, &crc, 4);
> +
> +		/* Calculate CRC for CMD5 Payload */
> +		crc = (u32)nxp_fw_dnld_update_crc(0UL, uart_config, uart_config_len);
> +		crc = (u32)SWAPL(crc);
> +		memcpy(uart_config + uart_config_len, &crc, 4);
> +		uart_config_len += 4;
> +
> +		serdev_device_write_buf(nxpdev->serdev, nxp_cmd5_header, req_len);
> +	} else {
> +		serdev_device_write_buf(nxpdev->serdev, uart_config, req_len);
> +		serdev_device_wait_until_sent(nxpdev->serdev, 0);
> +		ret = true;
> +	}
> +	return ret;
> +}
> +
> +static bool nxp_fw_change_timeout(struct hci_dev *hdev, u16 req_len)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	bool ret = false;
> +	u8 nxp_cmd7_header[HDR_LEN] = {0x07, 0x00, 0x00, 0x00,
> +								   0x70, 0x00, 0x00, 0x00,
> +								   0x00, 0x00, 0x00, 0x00,
> +								   0x5b, 0x88, 0xf8, 0xba};

Fix indentation.

> +
> +	nxpdev->fw_v3_offset_correction += req_len;
> +
> +	if (req_len == HDR_LEN) {
> +		serdev_device_write_buf(nxpdev->serdev, nxp_cmd7_header, req_len);
> +		serdev_device_wait_until_sent(nxpdev->serdev, 0);
> +		ret = true;
> +	}
> +	return ret;

Just use return true and return false directly.

> +}
> +
> +static u32 nxp_get_data_len(const u8 *buf)
> +{
> +	return (buf[8] | (buf[9] << 8));

Custom byte-order func? Use std ones instead.

> +}
> +
> +/* for legacy chipsets with V1 bootloader */
> +static int nxp_recv_fw_req_v1(struct hci_dev *hdev, struct sk_buff *skb)
> +{
> +	struct V1_DATA_REQ *req = skb_pull_data(skb, sizeof(struct V1_DATA_REQ));
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	const struct btnxpuart_data *nxp_data = nxpdev->nxp_data;
> +	static bool timeout_changed;
> +	static bool baudrate_changed;
> +	u32 requested_len;
> +	static u32 expected_len = HDR_LEN;
> +	int err;
> +
> +	if (!test_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state))
> +		return 0;
> +
> +	if (strlen(nxpdev->fw_name) == 0) {
> +		err = nxp_load_fw_params_for_chip_id(0xffff, hdev);
> +		if (err < 0)
> +			return err;
> +		timeout_changed = false;
> +		baudrate_changed = false;
> +		/* If secondary baudrate is not read from
> +		 * the conf file set default value from nxp_data
> +		 */
> +		if (nxpdev->fw_dnld_sec_baudrate == 0)
> +			nxpdev->fw_dnld_sec_baudrate = nxp_data->fw_dnld_sec_baudrate;
> +	}
> +
> +	if (nxpdev->fw_dnld_sec_baudrate != nxpdev->current_baudrate) {
> +		if (!timeout_changed) {
> +			nxp_send_ack(NXP_ACK_V1, hdev);
> +			timeout_changed = nxp_fw_change_timeout(hdev, req->len);

You never test if there was enough data? If there isn't req will be NULL
which you don't check before dereferencing req->len.

> +			return 0;
> +		}
> +		if (!baudrate_changed) {
> +			nxp_send_ack(NXP_ACK_V1, hdev);
> +			baudrate_changed = nxp_fw_change_baudrate(hdev, req->len);

Ditto.

> +			if (baudrate_changed) {
> +				serdev_device_set_baudrate(nxpdev->serdev,
> +								nxpdev->fw_dnld_sec_baudrate);
> +				nxpdev->current_baudrate = nxpdev->fw_dnld_sec_baudrate;
> +			}
> +			return 0;
> +		}
> +	}
> +
> +	if (!nxpdev->fw) {
> +		BT_INFO("Request Firmware: %s", nxpdev->fw_name);
> +		err = request_firmware(&nxpdev->fw, nxpdev->fw_name, &hdev->dev);
> +		if (err < 0) {
> +			BT_ERR("Firmware file %s not found", nxpdev->fw_name);
> +			clear_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
> +			return err;
> +		}
> +	}
> +
> +	if (req && (req->len ^ req->len_comp) == 0xffff) {
> +		nxp_send_ack(NXP_ACK_V1, hdev);
> +		if (req->len == 0) {
> +			BT_INFO("FW_Downloaded Successfully: %ld bytes", nxpdev->fw->size);
> +			clear_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
> +			wake_up_interruptible(&nxpdev->suspend_wait_q);
> +			return 0;
> +		}
> +		if (req->len & 0x01) {
> +			/* The CRC did not match at the other end.
> +			 * That's why the request to re-send.
> +			 * Simply send the same bytes again.
> +			 */
> +			requested_len = nxpdev->fw_sent_bytes;
> +			BT_ERR("CRC error. Resend %d bytes of FW.", requested_len);
> +		} else {
> +			/* Increment offset by number of previous successfully sent bytes */
> +			nxpdev->fw_dnld_offset += nxpdev->fw_sent_bytes;
> +			requested_len = req->len;
> +		}
> +
> +		/* The FW bin file is made up of many blocks of
> +		 * 16 byte header and payload data chunks. If the
> +		 * FW has requested a header, read the payload length
> +		 * info from the header, and then send the header.
> +		 * In the next iteration, the FW should request the
> +		 * payload data chunk, which should be equal to the
> +		 * payload length read from header. If there is a
> +		 * mismatch, clearly the driver and FW are out of sync,
> +		 * and we need to re-send the previous header again.
> +		 */
> +		if (requested_len == expected_len) {
> +			if (requested_len == HDR_LEN)
> +				expected_len = nxp_get_data_len(nxpdev->fw->data +
> +									nxpdev->fw_dnld_offset);
> +			else
> +				expected_len = HDR_LEN;

How can you ever end up into this else branch? Why assign expected_len 
here?

> +		} else {
> +			if (requested_len == HDR_LEN) {

Never true.

> +				/* FW download out of sync. Send previous chunk again */
> +				nxpdev->fw_dnld_offset -= nxpdev->fw_sent_bytes;
> +				expected_len = HDR_LEN;
> +			}
> +		}
> +
> +		if (nxpdev->fw_dnld_offset + requested_len <= nxpdev->fw->size)
> +			serdev_device_write_buf(nxpdev->serdev,
> +					nxpdev->fw->data + nxpdev->fw_dnld_offset,
> +					requested_len);
> +		nxpdev->fw_sent_bytes = requested_len;
> +	} else {
> +		BT_INFO("ERR: Send NAK");
> +		nxp_send_ack(NXP_NAK_V1, hdev);
> +	}
> +	return 0;
> +}
> +
> +static int nxp_recv_chip_ver_v3(struct hci_dev *hdev, struct sk_buff *skb)
> +{
> +	struct V3_START_IND *req = skb_pull_data(skb, sizeof(struct V3_START_IND));
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	const struct btnxpuart_data *nxp_data = nxpdev->nxp_data;
> +	int err = 0;
> +
> +	if (!test_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state))
> +		return 0;
> +
> +	if (req) {
> +		if (strlen(nxpdev->fw_name) == 0) {
> +			nxp_load_fw_params_for_chip_id(req->chip_id, hdev);
> +		} else if (!nxpdev->fw) {
> +			BT_INFO("Request Firmware: %s", nxpdev->fw_name);
> +			err = request_firmware(&nxpdev->fw, nxpdev->fw_name, &hdev->dev);
> +			if (err < 0) {
> +				BT_ERR("Firmware file %s not found", nxpdev->fw_name);
> +				clear_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
> +			}
> +		} else {
> +			/* If secondary baudrate is not read from
> +			 * the conf file set default value from nxp_data
> +			 */
> +			if (nxpdev->fw_dnld_sec_baudrate == 0)
> +				nxpdev->fw_dnld_sec_baudrate = nxp_data->fw_dnld_sec_baudrate;
> +			nxp_send_ack(NXP_ACK_V3, hdev);
> +		}
> +	}
> +	return err;
> +}
> +
> +static int nxp_recv_fw_req_v3(struct hci_dev *hdev, struct sk_buff *skb)
> +{
> +	struct V3_DATA_REQ *req = skb_pull_data(skb, sizeof(struct V3_DATA_REQ));
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	static bool timeout_changed;
> +	static bool baudrate_changed;
> +
> +	if (!req || !nxpdev || !strlen(nxpdev->fw_name) || !nxpdev->fw->data)
> +		return 0;

Who is expected to free the skb? These functions or one of the callers?
(Which one? I lost track of the callchain and error passing too).

> +
> +	if (!test_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state))
> +		return 0;
> +
> +	nxp_send_ack(NXP_ACK_V3, hdev);
> +
> +	if (nxpdev->fw_dnld_sec_baudrate != nxpdev->current_baudrate) {
> +		if (!timeout_changed) {
> +			timeout_changed = nxp_fw_change_timeout(hdev, req->len);
> +			return 0;
> +		}
> +
> +		if (!baudrate_changed) {
> +			baudrate_changed = nxp_fw_change_baudrate(hdev, req->len);
> +			if (baudrate_changed) {
> +				serdev_device_set_baudrate(nxpdev->serdev,
> +								nxpdev->fw_dnld_sec_baudrate);
> +				nxpdev->current_baudrate = nxpdev->fw_dnld_sec_baudrate;
> +			}
> +			return 0;
> +		}
> +	}
> +
> +	if (req->len == 0) {
> +		BT_INFO("FW_Downloaded Successfully: %ld bytes", nxpdev->fw->size);
> +		clear_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
> +		wake_up_interruptible(&nxpdev->suspend_wait_q);
> +		return 0;
> +	}
> +	if (req->error)
> +		BT_ERR("FW Download received err 0x%02X from chip. Resending FW chunk.",
> +			   req->error);
> +
> +	if (req->offset < nxpdev->fw_v3_offset_correction) {
> +		/* This scenario should ideally never occur.
> +		 * But if it ever does, FW is out of sync and
> +		 * needs a power cycle.
> +		 */
> +		BT_ERR("Something went wrong during FW download. Please power cycle and try again");
> +		return 0;
> +	}
> +
> +	serdev_device_write_buf(nxpdev->serdev,
> +				nxpdev->fw->data + req->offset - nxpdev->fw_v3_offset_correction,
> +				req->len);
> +
> +	return 0;
> +}
> +
> +static int nxp_set_baudrate_cmd(struct hci_dev *hdev, void *data)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	struct ps_data *psdata = nxpdev->psdata;
> +	u8 *pcmd = (u8 *)&nxpdev->new_baudrate;
> +	struct sk_buff *skb;
> +	u8 *status;
> +	int ret = 0;
> +
> +	if (!psdata)
> +		return -EFAULT;
> +
> +	psdata->driver_sent_cmd = true;	/* set flag to prevent re-sending command in nxp_enqueue */
> +	skb = __hci_cmd_sync(hdev, HCI_NXP_SET_OPER_SPEED, 4, pcmd, HCI_CMD_TIMEOUT);
> +	psdata->driver_sent_cmd = false;

Yeah, this is third one so make a helper for this. Why is this assigning 
true/false to a u8 member btw?

> +
> +	if (IS_ERR(skb)) {
> +		bt_dev_err(hdev, "Setting baudrate failed (%ld)",
> +			   PTR_ERR(skb));

One line.

> +		return PTR_ERR(skb);
> +	}
> +
> +	status = skb_pull_data(skb, 1);
> +	if (status) {
> +		if (*status == 0) {
> +			serdev_device_set_baudrate(nxpdev->serdev, nxpdev->new_baudrate);
> +			nxpdev->current_baudrate = nxpdev->new_baudrate;
> +		}
> +		ret = *status;
> +		BT_INFO("Set baudrate response: status=%d, baudrate=%d",
> +			*status, nxpdev->new_baudrate);

		return *status;

> +	}
> +
> +	return ret;

return 0;

drop ret variable

> +}
> +
> +/* NXP protocol */
> +static int nxp_setup(struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	const struct btnxpuart_data *nxp_data = nxpdev->nxp_data;
> +	const char *fw_name_dt;
> +	const char *fw_path = "nxp/";
> +	int ret = 0;
> +
> +	if (!serdev_device_get_cts(nxpdev->serdev)) {
> +		BT_INFO("CTS high. Need FW Download");
> +
> +		/* Try reading FW name from DT */
> +		if (!device_property_read_string(&nxpdev->serdev->dev, "firmware-name",
> +										 &fw_name_dt)) {
> +			strncpy(nxpdev->fw_name, fw_path, MAX_FW_FILE_NAME_LEN);
> +			strncpy(nxpdev->fw_name + strlen(fw_path), fw_name_dt,
> +					MAX_FW_FILE_NAME_LEN);

How can this second one be correct if you use +strlen(fw_path) for the 
pointer. Why not use snprintf()?

> +		} else {
> +			/* If no input from DT, parse conf file from user-space.
> +			 * FW name will be selected based on the chip bootloader
> +			 * signature read, and corresponding entry in conf file.
> +			 */
> +			ret = request_firmware(&nxpdev->fw_config, BT_FW_CONF_FILE, &hdev->dev);
> +			if (ret < 0) {
> +				BT_INFO("Firmware conf file not found: %s", BT_FW_CONF_FILE);
> +				clear_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
> +				goto err;
> +			}
> +			ret = nxp_parse_conf_file(hdev);
> +			release_firmware(nxpdev->fw_config);
> +			if (ret < 0) {
> +				BT_ERR("Error parsing config file: %s", BT_FW_CONF_FILE);
> +				goto err;
> +			}
> +		}
> +
> +		ret = nxp_download_firmware(hdev);
> +		if (ret < 0)
> +			goto err;
> +	} else {
> +		BT_INFO("CTS low. FW already running.");
> +	}
> +
> +	serdev_device_set_flow_control(nxpdev->serdev, 1);
> +
> +	/* If fw_init_baudrate is not read from
> +	 * the conf file set default value from nxp_data
> +	 */
> +	if (nxpdev->fw_init_baudrate == 0)

if (!xx)

> +		nxpdev->fw_init_baudrate = nxp_data->fw_init_baudrate;
> +	serdev_device_set_baudrate(nxpdev->serdev, nxpdev->fw_init_baudrate);
> +	nxpdev->current_baudrate = nxpdev->fw_init_baudrate;
> +
> +	/* If oper_speed is not read from
> +	 * the conf file set default value from nxp_data
> +	 */
> +	if (nxpdev->oper_speed == 0)

Ditto.

> +		nxpdev->oper_speed = nxp_data->oper_speed;
> +
> +	if (nxpdev->current_baudrate != nxpdev->oper_speed) {
> +		/* Queue cmd to set baudrate to oper-speed */
> +		nxpdev->new_baudrate = nxpdev->oper_speed;
> +		hci_cmd_sync_queue(hdev, nxp_set_baudrate_cmd, NULL, NULL);
> +	}
> +
> +	if (ps_init_work(hdev) == 0)

Ditto.

> +		ps_init_timer(hdev);
> +	ps_init(hdev);
> +err:
> +	return ret;
> +}
> +
> +static int nxp_enqueue(struct hci_dev *hdev, struct sk_buff *skb)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	struct ps_data *psdata = nxpdev->psdata;
> +	struct hci_command_hdr *hdr;
> +	u8 *param;
> +
> +	/* if commands are received from user space (e.g. hcitool), update
> +	 * driver flags accordingly and ask driver to re-send the command
> +	 */
> +	if (bt_cb(skb)->pkt_type == HCI_COMMAND_PKT && !psdata->driver_sent_cmd) {

Should you need to check psdata for NULL before dereferencing it?

> +		hdr = (struct hci_command_hdr *)skb->data;
> +		param = skb->data + HCI_COMMAND_HDR_SIZE;
> +		switch (__le16_to_cpu(hdr->opcode)) {
> +		case HCI_NXP_AUTO_SLEEP_MODE:
> +			if (hdr->plen >= 1) {
> +				if (param[0] == BT_PS_ENABLE)
> +					psdata->ps_mode = PS_MODE_ENABLE;
> +				else if (param[0] == BT_PS_DISABLE)
> +					psdata->ps_mode = PS_MODE_DISABLE;
> +				hci_cmd_sync_queue(hdev, send_ps_cmd, NULL, NULL);
> +				kfree_skb(skb);
> +				goto ret;
> +			}
> +			break;
> +		case HCI_NXP_WAKEUP_METHOD:
> +			if (hdr->plen >= 4) {
> +				switch (param[2]) {
> +				case BT_CTRL_WAKEUP_METHOD_DSR:
> +					psdata->wakeupmode = WAKEUP_METHOD_DTR;
> +					break;
> +				case BT_CTRL_WAKEUP_METHOD_BREAK:
> +				default:
> +					psdata->wakeupmode = WAKEUP_METHOD_BREAK;
> +					break;
> +				}
> +				hci_cmd_sync_queue(hdev, send_wakeup_method_cmd, NULL, NULL);
> +				kfree_skb(skb);
> +				goto ret;
> +			}
> +			break;
> +		case HCI_NXP_SET_OPER_SPEED:
> +			if (hdr->plen == 4) {
> +				nxpdev->new_baudrate = *((u32 *)param);
> +				hci_cmd_sync_queue(hdev, nxp_set_baudrate_cmd, NULL, NULL);
> +				kfree_skb(skb);
> +				goto ret;
> +			}
> +		}
> +	}
> +
> +	/* Prepend skb with frame type */
> +	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
> +	skb_queue_tail(&nxpdev->txq, skb);
> +
> +	btnxpuart_tx_wakeup(nxpdev);
> +ret:
> +	return 0;
> +}
> +
> +static struct sk_buff *nxp_dequeue(void *data)
> +{
> +	struct btnxpuart_dev *nxpdev = (struct btnxpuart_dev *)data;
> +
> +	ps_wakeup(nxpdev);
> +	ps_start_timer(nxpdev);
> +	return skb_dequeue(&nxpdev->txq);
> +}
> +
> +/* btnxpuart based on serdev */
> +static void btnxpuart_tx_work(struct work_struct *work)
> +{
> +	struct btnxpuart_dev *nxpdev = container_of(work, struct btnxpuart_dev,
> +						   tx_work);
> +	struct serdev_device *serdev = nxpdev->serdev;
> +	struct hci_dev *hdev = nxpdev->hdev;
> +
> +	if (!nxpdev->nxp_data->dequeue)
> +		return;
> +
> +	while (1) {
> +		clear_bit(BTNXPUART_TX_STATE_WAKEUP, &nxpdev->tx_state);
> +
> +		while (1) {
> +			struct sk_buff *skb = nxpdev->nxp_data->dequeue(nxpdev);
> +			int len;
> +
> +			if (!skb)
> +				break;
> +
> +			len = serdev_device_write_buf(serdev, skb->data,
> +										  skb->len);

One line.

> +			hdev->stat.byte_tx += len;
> +
> +			skb_pull(skb, len);
> +			if (skb->len > 0) {
> +				skb_queue_head(&nxpdev->txq, skb);
> +				break;
> +			}
> +
> +			switch (hci_skb_pkt_type(skb)) {
> +			case HCI_COMMAND_PKT:
> +				hdev->stat.cmd_tx++;
> +				break;
> +			case HCI_ACLDATA_PKT:
> +				hdev->stat.acl_tx++;
> +				break;
> +			case HCI_SCODATA_PKT:
> +				hdev->stat.sco_tx++;
> +				break;
> +			}
> +
> +			kfree_skb(skb);
> +		}
> +
> +		if (!test_bit(BTNXPUART_TX_STATE_WAKEUP, &nxpdev->tx_state))
> +			break;
> +	}
> +	clear_bit(BTNXPUART_TX_STATE_ACTIVE, &nxpdev->tx_state);
> +}
> +
> +static void btnxpuart_tx_wakeup(struct btnxpuart_dev *nxpdev)
> +{
> +	if (test_and_set_bit(BTNXPUART_TX_STATE_ACTIVE, &nxpdev->tx_state)) {
> +		set_bit(BTNXPUART_TX_STATE_WAKEUP, &nxpdev->tx_state);
> +		return;
> +	}
> +	schedule_work(&nxpdev->tx_work);
> +}
> +
> +static int btnxpuart_open(struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	int err;
> +
> +	err = serdev_device_open(nxpdev->serdev);
> +	if (err) {
> +		bt_dev_err(hdev, "Unable to open UART device %s",
> +			   dev_name(&nxpdev->serdev->dev));
> +		return err;
> +	}
> +
> +	if (nxpdev->nxp_data->open) {
> +		err = nxpdev->nxp_data->open(hdev);
> +		if (err) {
> +			serdev_device_close(nxpdev->serdev);
> +			return err;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int btnxpuart_close(struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	int err;
> +
> +	if (nxpdev->nxp_data->close) {
> +		err = nxpdev->nxp_data->close(hdev);
> +		if (err)
> +			return err;
> +	}
> +
> +	serdev_device_close(nxpdev->serdev);
> +
> +	return 0;
> +}
> +
> +static int btnxpuart_flush(struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +
> +	/* Flush any pending characters */
> +	serdev_device_write_flush(nxpdev->serdev);
> +	skb_queue_purge(&nxpdev->txq);
> +
> +	cancel_work_sync(&nxpdev->tx_work);
> +
> +	kfree_skb(nxpdev->rx_skb);
> +	nxpdev->rx_skb = NULL;
> +
> +	return 0;
> +}
> +
> +static int btnxpuart_setup(struct hci_dev *hdev)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +
> +	if (nxpdev->nxp_data->setup)
> +		return nxpdev->nxp_data->setup(hdev);
> +
> +	return 0;
> +}
> +
> +static int btnxpuart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +
> +	if (nxpdev->nxp_data->enqueue)
> +		nxpdev->nxp_data->enqueue(hdev, skb);
> +
> +	return 0;
> +}
> +
> +static int btnxpuart_receive_buf(struct serdev_device *serdev, const u8 *data,
> +								 size_t count)
> +{
> +	struct btnxpuart_dev *nxpdev = serdev_device_get_drvdata(serdev);
> +	const struct btnxpuart_data *nxp_data = nxpdev->nxp_data;
> +
> +	if (test_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state)) {
> +		if (*data != NXP_V1_FW_REQ_PKT && *data != NXP_V1_CHIP_VER_PKT &&
> +			*data != NXP_V3_FW_REQ_PKT && *data != NXP_V3_CHIP_VER_PKT) {

Fix indent.

> +			/* Unknown bootloader signature, skip without returning error */
> +			return count;
> +		}
> +	}
> +
> +	ps_start_timer(nxpdev);
> +
> +	nxpdev->rx_skb = h4_recv_buf(nxpdev->hdev, nxpdev->rx_skb, data, count,
> +						nxp_data->recv_pkts, nxp_data->recv_pkts_cnt);
> +	if (IS_ERR(nxpdev->rx_skb)) {
> +		int err = PTR_ERR(nxpdev->rx_skb);
> +
> +		bt_dev_err(nxpdev->hdev, "Frame reassembly failed (%d)", err);
> +		nxpdev->rx_skb = NULL;
> +		return err;
> +	}
> +	nxpdev->hdev->stat.byte_rx += count;
> +	return count;
> +}
> +
> +static void btnxpuart_write_wakeup(struct serdev_device *serdev)
> +{
> +	serdev_device_write_wakeup(serdev);
> +}
> +
> +static const struct serdev_device_ops btnxpuart_client_ops = {
> +	.receive_buf = btnxpuart_receive_buf,
> +	.write_wakeup = btnxpuart_write_wakeup,
> +};
> +
> +static int nxp_serdev_probe(struct serdev_device *serdev)
> +{
> +	struct hci_dev *hdev;
> +	struct btnxpuart_dev *nxpdev;
> +
> +	nxpdev = devm_kzalloc(&serdev->dev, sizeof(*nxpdev), GFP_KERNEL);
> +	if (!nxpdev)
> +		return -ENOMEM;
> +
> +	memset(nxpdev, 0, sizeof(*nxpdev));

Memsetting kzalloc'ed mem.

> +
> +	nxpdev->nxp_data = device_get_match_data(&serdev->dev);
> +
> +	nxpdev->serdev = serdev;
> +	serdev_device_set_drvdata(serdev, nxpdev);
> +
> +	serdev_device_set_client_ops(serdev, &btnxpuart_client_ops);
> +
> +	INIT_WORK(&nxpdev->tx_work, btnxpuart_tx_work);
> +	skb_queue_head_init(&nxpdev->txq);
> +
> +	/* Initialize and register HCI device */
> +	hdev = hci_alloc_dev();
> +	if (!hdev) {
> +		dev_err(&serdev->dev, "Can't allocate HCI device\n");
> +		return -ENOMEM;
> +	}
> +
> +	nxpdev->hdev = hdev;
> +
> +	hdev->bus = HCI_UART;
> +	hci_set_drvdata(hdev, nxpdev);
> +
> +	/* Only when vendor specific setup callback is provided, consider
> +	 * the manufacturer information valid. This avoids filling in the
> +	 * value for NXP when nothing is specified.
> +	 */
> +	if (nxpdev->nxp_data->setup)
> +		hdev->manufacturer = nxpdev->nxp_data->manufacturer;
> +
> +	hdev->open  = btnxpuart_open;
> +	hdev->close = btnxpuart_close;
> +	hdev->flush = btnxpuart_flush;
> +	hdev->setup = btnxpuart_setup;
> +	hdev->send  = btnxpuart_send_frame;
> +	SET_HCIDEV_DEV(hdev, &serdev->dev);
> +
> +	if (hci_register_dev(hdev) < 0) {
> +		dev_err(&serdev->dev, "Can't register HCI device\n");
> +		hci_free_dev(hdev);
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static void nxp_serdev_remove(struct serdev_device *serdev)
> +{
> +	struct btnxpuart_dev *nxpdev = serdev_device_get_drvdata(serdev);
> +	struct hci_dev *hdev = nxpdev->hdev;
> +
> +	/* Restore FW baudrate to fw_init_baudrate if changed.
> +	 * This will ensure FW baudrate is in sync with
> +	 * driver baudrate in case this driver is re-inserted.
> +	 */
> +	if (nxpdev->fw_init_baudrate != nxpdev->current_baudrate) {
> +		nxpdev->new_baudrate = nxpdev->fw_init_baudrate;
> +		nxp_set_baudrate_cmd(hdev, NULL);
> +	}
> +
> +	ps_cancel_timer(nxpdev);
> +	hci_unregister_dev(hdev);
> +	hci_free_dev(hdev);
> +}
> +
> +static const struct h4_recv_pkt nxp_recv_pkts[] = {
> +	{ H4_RECV_ACL,          .recv = hci_recv_frame },
> +	{ H4_RECV_SCO,          .recv = hci_recv_frame },
> +	{ H4_RECV_EVENT,        .recv = hci_recv_frame },
> +	{ NXP_RECV_FW_REQ_V1,   .recv = nxp_recv_fw_req_v1 },
> +	{ NXP_RECV_CHIP_VER_V3, .recv = nxp_recv_chip_ver_v3 },
> +	{ NXP_RECV_FW_REQ_V3,   .recv = nxp_recv_fw_req_v3 },
> +};
> +
> +static const struct btnxpuart_data nxp_generic_data = {
> +	.recv_pkts	= nxp_recv_pkts,
> +	.recv_pkts_cnt	= ARRAY_SIZE(nxp_recv_pkts),
> +	.manufacturer	= 18,
> +	.fw_dnld_pri_baudrate = 115200,
> +	.fw_dnld_sec_baudrate = 3000000,
> +	.fw_init_baudrate = 3000000,
> +	.oper_speed		= 3000000,
> +	.setup		= nxp_setup,
> +	.enqueue    = nxp_enqueue,
> +	.dequeue    = nxp_dequeue,
> +};
> +
> +static const struct btnxpuart_data nxp_legacy_data = {
> +	.recv_pkts	= nxp_recv_pkts,
> +	.recv_pkts_cnt	= ARRAY_SIZE(nxp_recv_pkts),
> +	.manufacturer	= 18,
> +	.fw_dnld_pri_baudrate = 115200,
> +	.fw_dnld_sec_baudrate = 3000000,
> +	.fw_init_baudrate = 115200,
> +	.oper_speed		= 3000000,
> +	.setup		= nxp_setup,
> +	.enqueue    = nxp_enqueue,
> +	.dequeue    = nxp_dequeue,
> +};
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id nxpuart_of_match_table[] = {
> +	{ .compatible = "nxp,nxp-generic-bt-chip", .data = &nxp_generic_data },
> +	{ .compatible = "nxp,nxp-legacy-bt-chip", .data = &nxp_legacy_data },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, nxpuart_of_match_table);
> +#endif
> +
> +static struct serdev_device_driver nxp_serdev_driver = {
> +	.probe = nxp_serdev_probe,
> +	.remove = nxp_serdev_remove,
> +	.driver = {
> +		.name = "btnxpuart",
> +		.of_match_table = of_match_ptr(nxpuart_of_match_table),
> +	},
> +};
> +
> +module_serdev_device_driver(nxp_serdev_driver);
> +
> +MODULE_AUTHOR("Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>");
> +MODULE_DESCRIPTION("NXP Bluetooth Serial driver v1.0 ");
> +MODULE_VERSION("v1.0");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/bluetooth/btnxp.h b/drivers/bluetooth/btnxp.h
> new file mode 100644
> index 000000000000..23ab11c1ce8d
> --- /dev/null
> +++ b/drivers/bluetooth/btnxp.h
> @@ -0,0 +1,230 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + *
> + *  NXP Bluetooth driver
> + *  Copyright 2018-2023 NXP
> + *
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef BT_NXP_H_
> +#define BT_NXP_H_
> +
> +#define BT_FW_CONF_FILE             "nxp/bt_mod_para.conf"
> +#define FW_NAME_TAG                 "fw_name"
> +#define OPER_SPEED_TAG              "oper_speed"
> +#define FW_DL_PRI_BAUDRATE_TAG      "fw_dl_pri_speed"
> +#define FW_DL_SEC_BAUDRATE_TAG      "fw_dl_sec_speed"
> +#define FW_INIT_BAUDRATE            "fw_init_speed"
> +
> +#define MAX_CHIP_NAME_LEN       20
> +#define MAX_FW_FILE_NAME_LEN    50
> +#define MAX_NO_OF_CHIPS_SUPPORT 20
> +
> +/* Default ps timeout period in milli-second */
> +#define PS_DEFAULT_TIMEOUT_PERIOD     2000
> +
> +/* wakeup methods */
> +#define WAKEUP_METHOD_DTR       0
> +#define WAKEUP_METHOD_BREAK     1
> +#define WAKEUP_METHOD_EXT_BREAK 2
> +#define WAKEUP_METHOD_RTS       3
> +#define WAKEUP_METHOD_INVALID   0xff
> +
> +/* power save mode status */
> +#define PS_MODE_DISABLE         0
> +#define PS_MODE_ENABLE          1
> +
> +/* Power Save Commands to ps_work_func  */
> +#define PS_CMD_EXIT_PS          1
> +#define PS_CMD_ENTER_PS         2
> +
> +/* power save state */
> +#define PS_STATE_AWAKE          0
> +#define PS_STATE_SLEEP          1
> +
> +/* Bluetooth vendor command : Sleep mode */
> +#define HCI_NXP_AUTO_SLEEP_MODE	0xFC23

Try to change all hex letters to lowercase.

> +/* Bluetooth vendor command : Wakeup method */
> +#define HCI_NXP_WAKEUP_METHOD	0xFC53
> +/* Bluetooth vendor command : Set operational baudrate */
> +#define HCI_NXP_SET_OPER_SPEED	0xFC09
> +
> +/* Bluetooth Power State : Vendor cmd params */
> +#define BT_PS_ENABLE			0x02
> +#define BT_PS_DISABLE			0x03
> +
> +/* Bluetooth Host Wakeup Methods */
> +#define BT_HOST_WAKEUP_METHOD_NONE      0x00
> +#define BT_HOST_WAKEUP_METHOD_DTR       0x01
> +#define BT_HOST_WAKEUP_METHOD_BREAK     0x02
> +#define BT_HOST_WAKEUP_METHOD_GPIO      0x03
> +#define BT_HOST_WAKEUP_DEFAULT_GPIO     5
> +
> +/* Bluetooth Chip Wakeup Methods */
> +#define BT_CTRL_WAKEUP_METHOD_DSR       0x00
> +#define BT_CTRL_WAKEUP_METHOD_BREAK     0x01
> +#define BT_CTRL_WAKEUP_METHOD_GPIO      0x02
> +#define BT_CTRL_WAKEUP_METHOD_EXT_BREAK 0x04
> +#define BT_CTRL_WAKEUP_METHOD_RTS       0x05
> +#define BT_CTRL_WAKEUP_DEFAULT_GPIO     4
> +
> +struct ps_data {
> +	u8    ps_mode;
> +	u8    cur_psmode;
> +	u8    ps_state;
> +	u8    ps_cmd;
> +	u8    wakeupmode;
> +	u8    cur_wakeupmode;
> +	u8    driver_sent_cmd;
> +	u8    timer_on;
> +	u32   interval;
> +	struct hci_dev *hdev;
> +	struct work_struct work;
> +	struct timer_list ps_timer;
> +};
> +
> +struct btnxpuart_data {
> +	const struct h4_recv_pkt *recv_pkts;
> +	int recv_pkts_cnt;
> +	unsigned int manufacturer;
> +	int (*open)(struct hci_dev *hdev);
> +	int (*close)(struct hci_dev *hdev);
> +	int (*setup)(struct hci_dev *hdev);
> +	int (*enqueue)(struct hci_dev *hdev, struct sk_buff *skb);
> +	struct sk_buff *(*dequeue)(void *data);
> +	u32 fw_dnld_pri_baudrate;
> +	u32 fw_dnld_sec_baudrate;
> +	u32 fw_init_baudrate;
> +	u32 oper_speed;
> +};
> +
> +struct btnxpuart_dev {
> +	struct hci_dev *hdev;
> +	struct serdev_device *serdev;
> +
> +	struct work_struct tx_work;
> +	unsigned long tx_state;
> +	struct sk_buff_head txq;
> +	struct sk_buff *rx_skb;
> +
> +	const struct firmware *fw;
> +	const struct firmware *fw_config;
> +	u8 fw_name[MAX_FW_FILE_NAME_LEN];
> +	u32 fw_dnld_offset;
> +	u32 fw_sent_bytes;
> +	u32 fw_v3_offset_correction;
> +	wait_queue_head_t suspend_wait_q;
> +
> +	u32 fw_dnld_pri_baudrate;
> +	u32 fw_dnld_sec_baudrate;
> +	u32 fw_init_baudrate;
> +	u32 oper_speed;
> +	u32 new_baudrate;
> +	u32 current_baudrate;
> +
> +	struct ps_data *psdata;
> +	const struct btnxpuart_data *nxp_data;
> +};
> +
> +struct chip_id_map_table {
> +	u16 chip_id;
> +	const u8 *chip_name;
> +};
> +
> +struct fw_params {
> +	u16 chip_id;
> +	u8  chip_name[MAX_CHIP_NAME_LEN];
> +	u8  fw_name[MAX_FW_FILE_NAME_LEN];
> +	u32 fw_dnld_pri_baudrate;
> +	u32 fw_dnld_sec_baudrate;
> +	u32 fw_init_baudrate;
> +	u32 oper_speed;
> +};
> +
> +#define NXP_V1_FW_REQ_PKT      0xA5
> +#define NXP_V1_CHIP_VER_PKT    0xAA
> +#define NXP_V3_FW_REQ_PKT      0xA7
> +#define NXP_V3_CHIP_VER_PKT    0xAB
> +
> +#define NXP_ACK_V1             0x5A
> +#define NXP_NAK_V1             0xBF
> +#define NXP_ACK_V3             0x7A
> +#define NXP_NAK_V3             0x7B
> +#define NXP_CRC_ERROR_V3       0x7C
> +
> +#define HDR_LEN					16
> +
> +#define NXP_RECV_FW_REQ_V1 \
> +	.type = NXP_V1_FW_REQ_PKT, \
> +	.hlen = 4, \
> +	.loff = 0, \
> +	.lsize = 0, \
> +	.maxlen = 4
> +
> +#define NXP_RECV_CHIP_VER_V3 \
> +	.type = NXP_V3_CHIP_VER_PKT, \
> +	.hlen = 4, \
> +	.loff = 0, \
> +	.lsize = 0, \
> +	.maxlen = 4
> +
> +#define NXP_RECV_FW_REQ_V3 \
> +	.type = NXP_V3_FW_REQ_PKT, \
> +	.hlen = 9, \
> +	.loff = 0, \
> +	.lsize = 0, \
> +	.maxlen = 9
> +
> +struct V1_DATA_REQ {
> +	u16 len;
> +	u16 len_comp;
> +} __packed;
> +
> +struct V3_DATA_REQ {
> +	u16 len;
> +	u32 offset;
> +	u16 error;
> +	u8 crc;
> +} __packed;
> +
> +struct V3_START_IND {
> +	u16 chip_id;
> +	u8 loader_ver;
> +	u8 crc;
> +} __packed;

Struct names should be lowercased. Multibyte fields need to specify 
byte-order?

> +/* UART register addresses of BT chip */
> +#define CLKDIVADDR       0x7f00008f
> +#define UARTDIVADDR      0x7f000090
> +#define UARTMCRADDR      0x7f000091
> +#define UARTREINITADDR   0x7f000092
> +#define UARTICRADDR      0x7f000093
> +#define UARTFCRADDR      0x7f000094
> +
> +#define MCR   0x00000022
> +#define INIT  0x00000001
> +#define ICR   0x000000c7
> +#define FCR   0x000000c7
> +
> +#define SWAPL(x) ((((x) >> 24) & 0xff) \
> +				 | (((x) >> 8) & 0xff00) \
> +				 | (((x) << 8) & 0xff0000L) \
> +				 | (((x) << 24) & 0xff000000L))

Perhaps something existing under include/ could do swap for you?

> +
> +#define POLYNOMIAL8				0x07
> +#define POLYNOMIAL32			0x04c11db7L
> +
> +static void btnxpuart_tx_wakeup(struct btnxpuart_dev *nxpdev);
> +
> +#endif
>

Hi Ilpo,

Thank you for your review comments and sorry for the delay in replying to some of your queries.

> From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> Sent: Wednesday, January 25, 2023 4:53 PM
> To: Neeraj sanjay kale <neeraj.sanjaykale@nxp.com>
> Cc: davem@davemloft.net; edumazet@google.com; kuba@kernel.org;
> pabeni@redhat.com; robh+dt@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; marcel@holtmann.org;
> johan.hedberg@gmail.com; luiz.dentz@gmail.com; Greg Kroah-Hartman
> <gregkh@linuxfoundation.org>; Jiri Slaby <jirislaby@kernel.org>; Netdev
> <netdev@vger.kernel.org>; devicetree@vger.kernel.org; LKML <linux-
> kernel@vger.kernel.org>; linux-bluetooth@vger.kernel.org; linux-serial
> <linux-serial@vger.kernel.org>; Amitkumar Karwar
> <amitkumar.karwar@nxp.com>; Rohit Fule <rohit.fule@nxp.com>; Sherry
> Sun <sherry.sun@nxp.com>
> Subject: Re: [PATCH v1 3/3] Bluetooth: NXP: Add protocol support for
> NXP Bluetooth chipsets
> 
> > This adds a driver based on serdev driver for the NXP BT serial
> > protocol based on running H:4, which can enable the built-in
> > Bluetooth device inside a generic NXP BT chip.
> >
> > This driver has Power Save feature that will put the chip into
> > sleep state whenever there is no activity for 2000ms, and will
> > be woken up when any activity is to be initiated.
> >
> > This driver enables the power save feature by default by sending
> > the vendor specific commands to the chip during setup.
> >
> > During setup, the driver is capable of reading the bootloader
> > signature unique to every chip, and downloading corresponding
> > FW file defined in a user-space config file. The firmware file
> > name can be defined in DTS file as well, in which case the
> > user-space config file will be ignored.
> >
> > Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
> > ---
> >  MAINTAINERS                |    7 +
> >  drivers/bluetooth/Kconfig  |   11 +
> >  drivers/bluetooth/Makefile |    1 +
> >  drivers/bluetooth/btnxp.c  | 1337
> ++++++++++++++++++++++++++++++++++++
> >  drivers/bluetooth/btnxp.h  |  230 +++++++
> >  5 files changed, 1586 insertions(+)
> >  create mode 100644 drivers/bluetooth/btnxp.c
> >  create mode 100644 drivers/bluetooth/btnxp.h
> >
> > +static int ps_init_work(struct hci_dev *hdev)
> > +{
> > +     struct ps_data *psdata = kzalloc(sizeof(*psdata), GFP_KERNEL);
> > +     struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> > +
> > +     if (!psdata) {
> > +             BT_ERR("Can't allocate control structure for Power Save feature");
> > +             return -ENOMEM;
> > +     }
> > +     nxpdev->psdata = psdata;
> > +
> > +     memset(psdata, 0, sizeof(*psdata));
> 
> Why memset to zero kzalloc'ed mem?
I have removed all memset calls after kzalloc.
> 



> > +static int send_ps_cmd(struct hci_dev *hdev, void *data)
> > +{
> > +     struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> > +     struct ps_data *psdata = nxpdev->psdata;
> > +     u8 pcmd;
> > +     struct sk_buff *skb;
> > +     u8 *status;
> > +
> > +     if (psdata->ps_mode ==  PS_MODE_ENABLE)
> > +             pcmd = BT_PS_ENABLE;
> > +     else
> > +             pcmd = BT_PS_DISABLE;
> > +
> > +     psdata->driver_sent_cmd = true; /* set flag to prevent re-sending
> command in nxp_enqueue */
> > +     skb = __hci_cmd_sync(hdev, HCI_NXP_AUTO_SLEEP_MODE, 1, &pcmd,
> HCI_CMD_TIMEOUT);
> > +     psdata->driver_sent_cmd = false;
> 
> A helper for these 3 lines?
Added a new function where ever setting psdata->driver_sent_cmd and __hci_cmd_sync() is needed.



> 
> Do you need to free the skb?
Yes. Freed skb's where ever it needs to be freed in v2 and v3 patches.



> > +     for (i = 0; i < map_table_size; i++) {
> 
> Isn't this just ARRAY_SIZE(chip_id_name_table)? use it directly here,
> no need for the extra variable?
> 
> > +             if (!strcmp(chip_id_name_table[i].chip_name, name_str))
> > +                     return chip_id_name_table[i].chip_id;
> > +     }
> > +
> > +     return 0;  /* invalid name_str */
> 
> Put such comment preferrably to function's comment if you want to note
> things like this or create a properly named define for it.
I have slightly changed the way FW Download behaves, and removed this function.



> strncpy(fw_mod_params[param_index].fw_name,
> > +                                                     value, MAX_FW_FILE_NAME_LEN);
> > +                                     } else if (!strcmp(label, OPER_SPEED_TAG)) {
> > +                                             ret = kstrtouint(value, 10,
> > +                                             &fw_mod_params[param_index].oper_speed);
> > +                                     } else if (!strcmp(label, FW_DL_PRI_BAUDRATE_TAG))
> {
> > +                                             ret = kstrtouint(value, 10,
> > +
> &fw_mod_params[param_index].fw_dnld_pri_baudrate);
> > +                                     } else if (!strcmp(label, FW_DL_SEC_BAUDRATE_TAG))
> {
> > +                                             ret = kstrtouint(value, 10,
> > +
> &fw_mod_params[param_index].fw_dnld_sec_baudrate);
> > +                                     } else if (!strcmp(label, FW_INIT_BAUDRATE)) {
> > +                                             ret = kstrtouint(value, 10,
> > +
> &fw_mod_params[param_index].fw_init_baudrate);
> > +                                     } else {
> > +                                             BT_ERR("Unknown tag: %s", label);
> > +                                             ret = -1;
> > +                                             goto err;
> > +                                     }
> 
> Your indent is way too deep here, refactor the line processing into
> another function to make it readable?
> 
> Wouldn't something like sscanf() make it a bit simpler?

Created a new function to handle updating this data and used sscanf().



> > +             } else {
> > +                     *dptr = sptr[i];
> > +                     dptr++;
> 
> What prevents dptr becoming larger than the size allocated for line?
Used array index method instead of dptr pointer to fill the line. Added check for index.

> > +static bool nxp_fw_change_baudrate(struct hci_dev *hdev, u16 req_len)
> > +{
> > +     struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> > +     static u8 nxp_cmd5_header[HDR_LEN] = {
> 
> It would be good to prefix HDR_LEN with something to make it more specific
> to this use case.
We need this HDR_LEN macro while sending cmd7 as well. Hence kept this unchanged.

> 
> > +                                                     0x05, 0x00, 0x00, 0x00,
> > +                                                     0x00, 0x00, 0x00, 0x00,
> > +                                                     0x2c, 0x00, 0x00, 0x00,
> > +                                                     0x77, 0xdb, 0xfd, 0xe0};
> > +     static u8 uart_config[60] = {0};
> 
> Is this some structure actually? You seem to be filling it always with
> the same stuff in same order?
> 
> You probably need to handle byte-order properly too.
Handled cmd5 and cmd7 in a proper way using structures and handled byte-ordering.

> > +static u32 nxp_get_data_len(const u8 *buf)
> > +{
> > +     return (buf[8] | (buf[9] << 8));
> 
> Custom byte-order func? Use std ones instead.
Resolved in v2 patch.

> > +     if (nxpdev->fw_dnld_sec_baudrate != nxpdev->current_baudrate) {
> > +             if (!timeout_changed) {
> > +                     nxp_send_ack(NXP_ACK_V1, hdev);
> > +                     timeout_changed = nxp_fw_change_timeout(hdev, req->len);
> 
> You never test if there was enough data? If there isn't req will be NULL
> which you don't check before dereferencing req->len.
Added check for req before dereferencing it.


> > +             if (req->len & 0x01) {
> > +                     /* The CRC did not match at the other end.
> > +                      * That's why the request to re-send.
> > +                      * Simply send the same bytes again.
> > +                      */
> > +                     requested_len = nxpdev->fw_sent_bytes;
> > +                     BT_ERR("CRC error. Resend %d bytes of FW.", requested_len);
> > +             } else {
> > +                     /* Increment offset by number of previous successfully sent
> bytes */
> > +                     nxpdev->fw_dnld_offset += nxpdev->fw_sent_bytes;
> > +                     requested_len = req->len;
> > +             }
> > +
> > +             /* The FW bin file is made up of many blocks of
> > +              * 16 byte header and payload data chunks. If the
> > +              * FW has requested a header, read the payload length
> > +              * info from the header, and then send the header.
> > +              * In the next iteration, the FW should request the
> > +              * payload data chunk, which should be equal to the
> > +              * payload length read from header. If there is a
> > +              * mismatch, clearly the driver and FW are out of sync,
> > +              * and we need to re-send the previous header again.
> > +              */
> > +             if (requested_len == expected_len) {
> > +                     if (requested_len == HDR_LEN)
> > +                             expected_len = nxp_get_data_len(nxpdev->fw->data +
> > +                                                                     nxpdev->fw_dnld_offset);
> > +                     else
> > +                             expected_len = HDR_LEN;
> 
> How can you ever end up into this else branch? Why assign expected_len
> here?
There are 2 scenarios where requested_len == expected_len.
One, where requested_len is 16, which means a header was requested.
Another, where requested_len is not 16, which means payload was requested.

So if header was requested, we calculate the payload length which should be equal to requested_len in next iteration.
Similarly, if payload was requested, then in the next iteration the FW should request for a 16 bit header.
The expected_len is expected to toggle between 2 values: 16 and (e.g.) 2048.

> 
> > +             } else {
> > +                     if (requested_len == HDR_LEN) {
> 
> Never true.
Ideally we should not end up in this else part, but there are various customers and module vendors who use NXP chipsets within their products, which are already out in the market. Whenever the driver sends the cmd5 and cmd7 packets, we sometimes observe this scenario where the FW requests 16 bit header in 2 consecutive iterations, and we need to be sure that we re-send the 16 bit header, and not the 16 bit payload. 
This happens when the chip updates it's baudrate while receiving the 1st header, and discards it due to CRC mismatch, and requests the header again.

>
> > +                             /* FW download out of sync. Send previous chunk again> */
> > +                            nxpdev->fw_dnld_offset -= nxpdev->fw_sent_bytes;
> > +                             expected_len = HDR_LEN;> > +                     }
> > +            }
> > +

> > +static int nxp_recv_fw_req_v3(struct hci_dev *hdev, struct sk_buff *skb)
> > +{
> > +     struct V3_DATA_REQ *req = skb_pull_data(skb, sizeof(struct
> V3_DATA_REQ));
> > +     struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> > +     static bool timeout_changed;
> > +     static bool baudrate_changed;
> > +
> > +     if (!req || !nxpdev || !strlen(nxpdev->fw_name) || !nxpdev->fw->data)
> > +             return 0;
> 
> Who is expected to free the skb? These functions or one of the callers?
> (Which one? I lost track of the callchain and error passing too).
Added kfree_skb() in the called functions.


> > +                     strncpy(nxpdev->fw_name, fw_path,
> MAX_FW_FILE_NAME_LEN);
> > +                     strncpy(nxpdev->fw_name + strlen(fw_path), fw_name_dt,
> > +                                     MAX_FW_FILE_NAME_LEN);
> 
> How can this second one be correct if you use +strlen(fw_path) for the
> pointer. Why not use snprintf()?
Replaced strncpy with snprintfs()



> > +static int nxp_enqueue(struct hci_dev *hdev, struct sk_buff *skb)
> > +{
> > +     struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> > +     struct ps_data *psdata = nxpdev->psdata;
> > +     struct hci_command_hdr *hdr;
> > +     u8 *param;
> > +
> > +     /* if commands are received from user space (e.g. hcitool), update
> > +      * driver flags accordingly and ask driver to re-send the command
> > +      */
> > +     if (bt_cb(skb)->pkt_type == HCI_COMMAND_PKT && !psdata-
> >driver_sent_cmd) {
> 
> Should you need to check psdata for NULL before dereferencing it?
Added checks for psdata before dereferencing it.


> > +/* Bluetooth vendor command : Sleep mode */
> > +#define HCI_NXP_AUTO_SLEEP_MODE      0xFC23
> 
> Try to change all hex letters to lowercase.
Changed all hex letters to lowercase.

> > +struct V1_DATA_REQ {
> > +     u16 len;
> > +     u16 len_comp;
> > +} __packed;
> > +
> > +struct V3_DATA_REQ {
> > +     u16 len;
> > +     u32 offset;
> > +     u16 error;
> > +     u8 crc;
> > +} __packed;
> > +
> > +struct V3_START_IND {
> > +     u16 chip_id;
> > +     u8 loader_ver;
> > +     u8 crc;
> > +} __packed;
> 
> Struct names should be lowercased. Multibyte fields need to specify
> byte-order?
Resolved.

> > +
> > +#define SWAPL(x) ((((x) >> 24) & 0xff) \
> > +                              | (((x) >> 8) & 0xff00) \
> > +                              | (((x) << 8) & 0xff0000L) \
> > +                              | (((x) << 24) & 0xff000000L))
> 
> Perhaps something existing under include/ could do swap for you?
Added call to a standard swab32() function.

> --
>  i.

Please review the V3 patch and let me know if you have any suggestions or comments.

Thank you,
Neeraj

> > Hi Ilpo,
> >
> > Thank you for your review comments and sorry for the delay in replying to
> some of your queries.
> 
> I made some additional comments against v2 and I meant those ones were
> not addressed, the ones I made for v1 you've addressed I think.
> 
> --
>  i.
> 
Hi Ilpo,

I checked with my colleagues Amitkumar and Rohit (in CC) and we can't seem to find your comments on V2 patch in our inbox.
It might have probably been blocked by firewall or due to some other issue we have not received it.

Maybe you could please re-send that email and I can quickly take a look at it and resolve them.

Thanks,
Neeraj

Dear Neeraj,


Am 13.02.23 um 18:25 schrieb Neeraj sanjay kale:

>>> Thank you for your review comments and sorry for the delay in
>>> replying to some of your queries.
>> 
>> I made some additional comments against v2 and I meant those ones
>> were not addressed, the ones I made for v1 you've addressed I
>> think.

> I checked with my colleagues Amitkumar and Rohit (in CC) and we can't
> seem to find your comments on V2 patch in our inbox. It might have
> probably been blocked by firewall or due to some other issue we have
> not received it.
> 
> Maybe you could please re-send that email and I can quickly take a
> look at it and resolve them.

lore.kernel.org allows you to access the messages. I found Ilpo’s reply [1].


Kind regards,

Paul


[1]: 
https://lore.kernel.org/linux-bluetooth/1dde194e-2e44-663d-b128-f8ef7edd03f@linux.intel.com/