// SPDX-License-Identifier: GPL-2.0/* * Generic USB GNSS receiver driver * * Copyright (C) 2021 Johan Hovold <johan@kernel.org> */ #include <linux/errno.h>#include <linux/gnss.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/usb.h> #define GNSS_USB_READ_BUF_LEN	512#define GNSS_USB_WRITE_TIMEOUT	1000 static const struct usb_device_id gnss_usb_id_table[] = {	{ USB_DEVICE(0x1199, 0xb000) },		/* Sierra Wireless XM1210 */	{ }};MODULE_DEVICE_TABLE(usb, gnss_usb_id_table); struct gnss_usb {	struct usb_device *udev;	struct usb_interface *intf;	struct gnss_device *gdev;	struct urb *read_urb;	unsigned int write_pipe;}; static void gnss_usb_rx_complete(struct urb *urb){	struct gnss_usb *gusb = urb->context;	struct gnss_device *gdev = gusb->gdev;	int status = urb->status;	int len;	int ret; 	switch (status) {	case 0:		break;	case -ENOENT:	case -ECONNRESET:	case -ESHUTDOWN:		dev_dbg(&gdev->dev, "urb stopped: %d\n", status);		return;	case -EPIPE:		dev_err(&gdev->dev, "urb stopped: %d\n", status);		return;	default:		dev_dbg(&gdev->dev, "nonzero urb status: %d\n", status);		goto resubmit;	} 	len = urb->actual_length;	if (len == 0)		goto resubmit; 	ret = gnss_insert_raw(gdev, urb->transfer_buffer, len);	if (ret < len)		dev_dbg(&gdev->dev, "dropped %d bytes\n", len - ret);resubmit:	ret = usb_submit_urb(urb, GFP_ATOMIC);	if (ret && ret != -EPERM && ret != -ENODEV)		dev_err(&gdev->dev, "failed to resubmit urb: %d\n", ret);} static int gnss_usb_open(struct gnss_device *gdev){	struct gnss_usb *gusb = gnss_get_drvdata(gdev);	int ret; 	ret = usb_submit_urb(gusb->read_urb, GFP_KERNEL);	if (ret) {		if (ret != -EPERM && ret != -ENODEV)			dev_err(&gdev->dev, "failed to submit urb: %d\n", ret);		return ret;	} 	return 0;} static void gnss_usb_close(struct gnss_device *gdev){	struct gnss_usb *gusb = gnss_get_drvdata(gdev); 	usb_kill_urb(gusb->read_urb);} static int gnss_usb_write_raw(struct gnss_device *gdev,		const unsigned char *buf, size_t count){	struct gnss_usb *gusb = gnss_get_drvdata(gdev);	void *tbuf;	int ret; 	tbuf = kmemdup(buf, count, GFP_KERNEL);	if (!tbuf)		return -ENOMEM; 	ret = usb_bulk_msg(gusb->udev, gusb->write_pipe, tbuf, count, NULL,			GNSS_USB_WRITE_TIMEOUT);	kfree(tbuf);	if (ret)		return ret; 	return count;} static const struct gnss_operations gnss_usb_gnss_ops = {	.open		= gnss_usb_open,	.close		= gnss_usb_close,	.write_raw	= gnss_usb_write_raw,}; static int gnss_usb_probe(struct usb_interface *intf, const struct usb_device_id *id){	struct usb_device *udev = interface_to_usbdev(intf);	struct usb_endpoint_descriptor *in, *out;	struct gnss_device *gdev;	struct gnss_usb *gusb;	struct urb *urb;	size_t buf_len;	void *buf;	int ret; 	ret = usb_find_common_endpoints(intf->cur_altsetting, &in, &out, NULL,			NULL);	if (ret)		return ret; 	gusb = kzalloc_obj(*gusb);	if (!gusb)		return -ENOMEM; 	gdev = gnss_allocate_device(&intf->dev);	if (!gdev) {		ret = -ENOMEM;		goto err_free_gusb;	} 	gdev->ops = &gnss_usb_gnss_ops;	gdev->type = GNSS_TYPE_NMEA;	gnss_set_drvdata(gdev, gusb); 	urb = usb_alloc_urb(0, GFP_KERNEL);	if (!urb) {		ret = -ENOMEM;		goto err_put_gdev;	} 	buf_len = max(usb_endpoint_maxp(in), GNSS_USB_READ_BUF_LEN); 	buf = kzalloc(buf_len, GFP_KERNEL);	if (!buf) {		ret = -ENOMEM;		goto err_free_urb;	} 	usb_fill_bulk_urb(urb, udev,			usb_rcvbulkpipe(udev, usb_endpoint_num(in)),			buf, buf_len, gnss_usb_rx_complete, gusb); 	gusb->intf = intf;	gusb->udev = udev;	gusb->gdev = gdev;	gusb->read_urb = urb;	gusb->write_pipe = usb_sndbulkpipe(udev, usb_endpoint_num(out)); 	ret = gnss_register_device(gdev);	if (ret)		goto err_free_buf; 	usb_set_intfdata(intf, gusb); 	return 0; err_free_buf:	kfree(buf);err_free_urb:	usb_free_urb(urb);err_put_gdev:	gnss_put_device(gdev);err_free_gusb:	kfree(gusb); 	return ret;} static void gnss_usb_disconnect(struct usb_interface *intf){	struct gnss_usb *gusb = usb_get_intfdata(intf); 	gnss_deregister_device(gusb->gdev); 	kfree(gusb->read_urb->transfer_buffer);	usb_free_urb(gusb->read_urb);	gnss_put_device(gusb->gdev);	kfree(gusb);} static struct usb_driver gnss_usb_driver = {	.name		= "gnss-usb",	.probe		= gnss_usb_probe,	.disconnect	= gnss_usb_disconnect,	.id_table	= gnss_usb_id_table,};module_usb_driver(gnss_usb_driver); MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");MODULE_DESCRIPTION("Generic USB GNSS receiver driver");MODULE_LICENSE("GPL v2");