1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Generic USB GNSS receiver driver
4 *
5 * Copyright (C) 2021 Johan Hovold <johan@kernel.org>
6 */
7
8#include <linux/errno.h>
9#include <linux/gnss.h>
10#include <linux/init.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/usb.h>
15
16#define GNSS_USB_READ_BUF_LEN	512
17#define GNSS_USB_WRITE_TIMEOUT	1000
18
19static const struct usb_device_id gnss_usb_id_table[] = {
20	{ USB_DEVICE(0x1199, 0xb000) },		/* Sierra Wireless XM1210 */
21	{ }
22};
23MODULE_DEVICE_TABLE(usb, gnss_usb_id_table);
24
25struct gnss_usb {
26	struct usb_device *udev;
27	struct usb_interface *intf;
28	struct gnss_device *gdev;
29	struct urb *read_urb;
30	unsigned int write_pipe;
31};
32
33static void gnss_usb_rx_complete(struct urb *urb)
34{
35	struct gnss_usb *gusb = urb->context;
36	struct gnss_device *gdev = gusb->gdev;
37	int status = urb->status;
38	int len;
39	int ret;
40
41	switch (status) {
42	case 0:
43		break;
44	case -ENOENT:
45	case -ECONNRESET:
46	case -ESHUTDOWN:
47		dev_dbg(&gdev->dev, "urb stopped: %d\n", status);
48		return;
49	case -EPIPE:
50		dev_err(&gdev->dev, "urb stopped: %d\n", status);
51		return;
52	default:
53		dev_dbg(&gdev->dev, "nonzero urb status: %d\n", status);
54		goto resubmit;
55	}
56
57	len = urb->actual_length;
58	if (len == 0)
59		goto resubmit;
60
61	ret = gnss_insert_raw(gdev, urb->transfer_buffer, len);
62	if (ret < len)
63		dev_dbg(&gdev->dev, "dropped %d bytes\n", len - ret);
64resubmit:
65	ret = usb_submit_urb(urb, GFP_ATOMIC);
66	if (ret && ret != -EPERM && ret != -ENODEV)
67		dev_err(&gdev->dev, "failed to resubmit urb: %d\n", ret);
68}
69
70static int gnss_usb_open(struct gnss_device *gdev)
71{
72	struct gnss_usb *gusb = gnss_get_drvdata(gdev);
73	int ret;
74
75	ret = usb_submit_urb(gusb->read_urb, GFP_KERNEL);
76	if (ret) {
77		if (ret != -EPERM && ret != -ENODEV)
78			dev_err(&gdev->dev, "failed to submit urb: %d\n", ret);
79		return ret;
80	}
81
82	return 0;
83}
84
85static void gnss_usb_close(struct gnss_device *gdev)
86{
87	struct gnss_usb *gusb = gnss_get_drvdata(gdev);
88
89	usb_kill_urb(gusb->read_urb);
90}
91
92static int gnss_usb_write_raw(struct gnss_device *gdev,
93		const unsigned char *buf, size_t count)
94{
95	struct gnss_usb *gusb = gnss_get_drvdata(gdev);
96	void *tbuf;
97	int ret;
98
99	tbuf = kmemdup(buf, count, GFP_KERNEL);
100	if (!tbuf)
101		return -ENOMEM;
102
103	ret = usb_bulk_msg(gusb->udev, gusb->write_pipe, tbuf, count, NULL,
104			GNSS_USB_WRITE_TIMEOUT);
105	kfree(tbuf);
106	if (ret)
107		return ret;
108
109	return count;
110}
111
112static const struct gnss_operations gnss_usb_gnss_ops = {
113	.open		= gnss_usb_open,
114	.close		= gnss_usb_close,
115	.write_raw	= gnss_usb_write_raw,
116};
117
118static int gnss_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
119{
120	struct usb_device *udev = interface_to_usbdev(intf);
121	struct usb_endpoint_descriptor *in, *out;
122	struct gnss_device *gdev;
123	struct gnss_usb *gusb;
124	struct urb *urb;
125	size_t buf_len;
126	void *buf;
127	int ret;
128
129	ret = usb_find_common_endpoints(intf->cur_altsetting, &in, &out, NULL,
130			NULL);
131	if (ret)
132		return ret;
133
134	gusb = kzalloc(sizeof(*gusb), GFP_KERNEL);
135	if (!gusb)
136		return -ENOMEM;
137
138	gdev = gnss_allocate_device(&intf->dev);
139	if (!gdev) {
140		ret = -ENOMEM;
141		goto err_free_gusb;
142	}
143
144	gdev->ops = &gnss_usb_gnss_ops;
145	gdev->type = GNSS_TYPE_NMEA;
146	gnss_set_drvdata(gdev, gusb);
147
148	urb = usb_alloc_urb(0, GFP_KERNEL);
149	if (!urb) {
150		ret = -ENOMEM;
151		goto err_put_gdev;
152	}
153
154	buf_len = max(usb_endpoint_maxp(in), GNSS_USB_READ_BUF_LEN);
155
156	buf = kzalloc(buf_len, GFP_KERNEL);
157	if (!buf) {
158		ret = -ENOMEM;
159		goto err_free_urb;
160	}
161
162	usb_fill_bulk_urb(urb, udev,
163			usb_rcvbulkpipe(udev, usb_endpoint_num(in)),
164			buf, buf_len, gnss_usb_rx_complete, gusb);
165
166	gusb->intf = intf;
167	gusb->udev = udev;
168	gusb->gdev = gdev;
169	gusb->read_urb = urb;
170	gusb->write_pipe = usb_sndbulkpipe(udev, usb_endpoint_num(out));
171
172	ret = gnss_register_device(gdev);
173	if (ret)
174		goto err_free_buf;
175
176	usb_set_intfdata(intf, gusb);
177
178	return 0;
179
180err_free_buf:
181	kfree(buf);
182err_free_urb:
183	usb_free_urb(urb);
184err_put_gdev:
185	gnss_put_device(gdev);
186err_free_gusb:
187	kfree(gusb);
188
189	return ret;
190}
191
192static void gnss_usb_disconnect(struct usb_interface *intf)
193{
194	struct gnss_usb *gusb = usb_get_intfdata(intf);
195
196	gnss_deregister_device(gusb->gdev);
197
198	kfree(gusb->read_urb->transfer_buffer);
199	usb_free_urb(gusb->read_urb);
200	gnss_put_device(gusb->gdev);
201	kfree(gusb);
202}
203
204static struct usb_driver gnss_usb_driver = {
205	.name		= "gnss-usb",
206	.probe		= gnss_usb_probe,
207	.disconnect	= gnss_usb_disconnect,
208	.id_table	= gnss_usb_id_table,
209};
210module_usb_driver(gnss_usb_driver);
211
212MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
213MODULE_DESCRIPTION("Generic USB GNSS receiver driver");
214MODULE_LICENSE("GPL v2");
215