Re: [PATCH v12 4/4] Bluetooth: NXP: Add protocol support for NXP Bluetooth chipsets

[Simon Horman <simon.horman@corigine.com>]

On Wed, Mar 15, 2023 at 05:33:26PM +0530, 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 an 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 over UART.
> 
> This driver enables the power save feature by default by sending the vendor
> specific commands to the chip during setup.
> 
> During setup, the driver checks if a FW is already running on the chip
> by waiting for the bootloader signature, and downloads device specific FW
> file into the chip over UART if bootloader signature is received..
> 
> Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

...

> +static int nxp_set_ind_reset(struct hci_dev *hdev, void *data)
> +{
> +	struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
> +	struct sk_buff *skb;
> +	u8 *status;
> +	u8 pcmd = 0;
> +	int err = 0;
> +
> +	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) {
> +		if (*status == 0) {
> +			set_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);

nit: perhaps this can be written more idiomatically as:

	if (!status || *status)
		goto free_skb;

	set_bit(BTNXPUART_FW_DOWNLOADING, &nxpdev->tx_state);
	...

> +			err = nxp_download_firmware(hdev);
> +			if (err < 0)
> +				goto free_skb;
> +			serdev_device_set_baudrate(nxpdev->serdev, nxpdev->fw_init_baudrate);
> +			nxpdev->current_baudrate = nxpdev->fw_init_baudrate;
> +			hci_cmd_sync_queue(hdev, send_wakeup_method_cmd, NULL, NULL);
> +			hci_cmd_sync_queue(hdev, send_ps_cmd, NULL, NULL);
> +		}
> +	}
> +
> +free_skb:
> +	kfree_skb(skb);
> +	return err;
> +}

...