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 
10 struct 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 
17 static 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 
32 static 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 
49 static 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 
57 static 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 
70 static 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 
83 static __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 
91 static 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 
99 static 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 
113 static 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 
141 static 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 
148 static 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 };
155 MODULE_DEVICE_TABLE(rpmsg, rpmsg_wwan_ctrl_id_table);
156 
157 static 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 };
163 module_rpmsg_driver(rpmsg_wwan_ctrl_driver);
164 
165 MODULE_LICENSE("GPL v2");
166 MODULE_DESCRIPTION("RPMSG WWAN CTRL Driver");
167 MODULE_AUTHOR("Stephan Gerhold <stephan@gerhold.net>");
168