1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2021, Stephan Gerhold <stephan@gerhold.net> */
3#include <linux/kernel.h>
4#include <linux/mod_devicetable.h>
5#include <linux/module.h>
6#include <linux/platform_device.h>
7#include <linux/rpmsg.h>
8#include <linux/wwan.h>
9
10struct rpmsg_wwan_dev {
11	/* Lower level is a rpmsg dev, upper level is a wwan port */
12	struct rpmsg_device *rpdev;
13	struct wwan_port *wwan_port;
14	struct rpmsg_endpoint *ept;
15};
16
17static int rpmsg_wwan_ctrl_callback(struct rpmsg_device *rpdev,
18				    void *buf, int len, void *priv, u32 src)
19{
20	struct rpmsg_wwan_dev *rpwwan = priv;
21	struct sk_buff *skb;
22
23	skb = alloc_skb(len, GFP_ATOMIC);
24	if (!skb)
25		return -ENOMEM;
26
27	skb_put_data(skb, buf, len);
28	wwan_port_rx(rpwwan->wwan_port, skb);
29	return 0;
30}
31
32static int rpmsg_wwan_ctrl_start(struct wwan_port *port)
33{
34	struct rpmsg_wwan_dev *rpwwan = wwan_port_get_drvdata(port);
35	struct rpmsg_channel_info chinfo = {
36		.src = rpwwan->rpdev->src,
37		.dst = RPMSG_ADDR_ANY,
38	};
39
40	strncpy(chinfo.name, rpwwan->rpdev->id.name, RPMSG_NAME_SIZE);
41	rpwwan->ept = rpmsg_create_ept(rpwwan->rpdev, rpmsg_wwan_ctrl_callback,
42				       rpwwan, chinfo);
43	if (!rpwwan->ept)
44		return -EREMOTEIO;
45
46	return 0;
47}
48
49static void rpmsg_wwan_ctrl_stop(struct wwan_port *port)
50{
51	struct rpmsg_wwan_dev *rpwwan = wwan_port_get_drvdata(port);
52
53	rpmsg_destroy_ept(rpwwan->ept);
54	rpwwan->ept = NULL;
55}
56
57static int rpmsg_wwan_ctrl_tx(struct wwan_port *port, struct sk_buff *skb)
58{
59	struct rpmsg_wwan_dev *rpwwan = wwan_port_get_drvdata(port);
60	int ret;
61
62	ret = rpmsg_trysend(rpwwan->ept, skb->data, skb->len);
63	if (ret)
64		return ret;
65
66	consume_skb(skb);
67	return 0;
68}
69
70static int rpmsg_wwan_ctrl_tx_blocking(struct wwan_port *port, struct sk_buff *skb)
71{
72	struct rpmsg_wwan_dev *rpwwan = wwan_port_get_drvdata(port);
73	int ret;
74
75	ret = rpmsg_send(rpwwan->ept, skb->data, skb->len);
76	if (ret)
77		return ret;
78
79	consume_skb(skb);
80	return 0;
81}
82
83static __poll_t rpmsg_wwan_ctrl_tx_poll(struct wwan_port *port,
84					struct file *filp, poll_table *wait)
85{
86	struct rpmsg_wwan_dev *rpwwan = wwan_port_get_drvdata(port);
87
88	return rpmsg_poll(rpwwan->ept, filp, wait);
89}
90
91static const struct wwan_port_ops rpmsg_wwan_pops = {
92	.start = rpmsg_wwan_ctrl_start,
93	.stop = rpmsg_wwan_ctrl_stop,
94	.tx = rpmsg_wwan_ctrl_tx,
95	.tx_blocking = rpmsg_wwan_ctrl_tx_blocking,
96	.tx_poll = rpmsg_wwan_ctrl_tx_poll,
97};
98
99static struct device *rpmsg_wwan_find_parent(struct device *dev)
100{
101	/* Select first platform device as parent for the WWAN ports.
102	 * On Qualcomm platforms this is usually the platform device that
103	 * represents the modem remote processor. This might need to be
104	 * adjusted when adding device IDs for other platforms.
105	 */
106	for (dev = dev->parent; dev; dev = dev->parent) {
107		if (dev_is_platform(dev))
108			return dev;
109	}
110	return NULL;
111}
112
113static int rpmsg_wwan_ctrl_probe(struct rpmsg_device *rpdev)
114{
115	struct rpmsg_wwan_dev *rpwwan;
116	struct wwan_port *port;
117	struct device *parent;
118
119	parent = rpmsg_wwan_find_parent(&rpdev->dev);
120	if (!parent)
121		return -ENODEV;
122
123	rpwwan = devm_kzalloc(&rpdev->dev, sizeof(*rpwwan), GFP_KERNEL);
124	if (!rpwwan)
125		return -ENOMEM;
126
127	rpwwan->rpdev = rpdev;
128	dev_set_drvdata(&rpdev->dev, rpwwan);
129
130	/* Register as a wwan port, id.driver_data contains wwan port type */
131	port = wwan_create_port(parent, rpdev->id.driver_data,
132				&rpmsg_wwan_pops, NULL, rpwwan);
133	if (IS_ERR(port))
134		return PTR_ERR(port);
135
136	rpwwan->wwan_port = port;
137
138	return 0;
139};
140
141static void rpmsg_wwan_ctrl_remove(struct rpmsg_device *rpdev)
142{
143	struct rpmsg_wwan_dev *rpwwan = dev_get_drvdata(&rpdev->dev);
144
145	wwan_remove_port(rpwwan->wwan_port);
146}
147
148static const struct rpmsg_device_id rpmsg_wwan_ctrl_id_table[] = {
149	/* RPMSG channels for Qualcomm SoCs with integrated modem */
150	{ .name = "DATA5_CNTL", .driver_data = WWAN_PORT_QMI },
151	{ .name = "DATA4", .driver_data = WWAN_PORT_AT },
152	{ .name = "DATA1", .driver_data = WWAN_PORT_AT },
153	{},
154};
155MODULE_DEVICE_TABLE(rpmsg, rpmsg_wwan_ctrl_id_table);
156
157static struct rpmsg_driver rpmsg_wwan_ctrl_driver = {
158	.drv.name = "rpmsg_wwan_ctrl",
159	.id_table = rpmsg_wwan_ctrl_id_table,
160	.probe = rpmsg_wwan_ctrl_probe,
161	.remove = rpmsg_wwan_ctrl_remove,
162};
163module_rpmsg_driver(rpmsg_wwan_ctrl_driver);
164
165MODULE_LICENSE("GPL v2");
166MODULE_DESCRIPTION("RPMSG WWAN CTRL Driver");
167MODULE_AUTHOR("Stephan Gerhold <stephan@gerhold.net>");
168