1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2021, MediaTek Inc.
4  * Copyright (c) 2021-2022, Intel Corporation.
5  *
6  * Authors:
7  *  Amir Hanania <amir.hanania@intel.com>
8  *  Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
9  *  Haijun Liu <haijun.liu@mediatek.com>
10  *  Moises Veleta <moises.veleta@intel.com>
11  *  Ricardo Martinez <ricardo.martinez@linux.intel.com>
12  *
13  * Contributors:
14  *  Andy Shevchenko <andriy.shevchenko@linux.intel.com>
15  *  Chiranjeevi Rapolu <chiranjeevi.rapolu@intel.com>
16  *  Eliot Lee <eliot.lee@intel.com>
17  *  Sreehari Kancharla <sreehari.kancharla@intel.com>
18  */
19 
20 #include <linux/atomic.h>
21 #include <linux/bitfield.h>
22 #include <linux/dev_printk.h>
23 #include <linux/err.h>
24 #include <linux/gfp.h>
25 #include <linux/minmax.h>
26 #include <linux/netdevice.h>
27 #include <linux/skbuff.h>
28 #include <linux/spinlock.h>
29 #include <linux/string.h>
30 #include <linux/wwan.h>
31 
32 #include "t7xx_port.h"
33 #include "t7xx_port_proxy.h"
34 #include "t7xx_state_monitor.h"
35 
36 static int t7xx_port_ctrl_start(struct wwan_port *port)
37 {
38 	struct t7xx_port *port_mtk = wwan_port_get_drvdata(port);
39 
40 	if (atomic_read(&port_mtk->usage_cnt))
41 		return -EBUSY;
42 
43 	atomic_inc(&port_mtk->usage_cnt);
44 	return 0;
45 }
46 
47 static void t7xx_port_ctrl_stop(struct wwan_port *port)
48 {
49 	struct t7xx_port *port_mtk = wwan_port_get_drvdata(port);
50 
51 	atomic_dec(&port_mtk->usage_cnt);
52 }
53 
54 static int t7xx_port_ctrl_tx(struct wwan_port *port, struct sk_buff *skb)
55 {
56 	struct t7xx_port *port_private = wwan_port_get_drvdata(port);
57 	const struct t7xx_port_conf *port_conf;
58 	struct sk_buff *cur = skb, *cloned;
59 	struct t7xx_fsm_ctl *ctl;
60 	enum md_state md_state;
61 	int cnt = 0, ret;
62 
63 	if (!port_private->chan_enable)
64 		return -EINVAL;
65 
66 	port_conf = port_private->port_conf;
67 	ctl = port_private->t7xx_dev->md->fsm_ctl;
68 	md_state = t7xx_fsm_get_md_state(ctl);
69 	if (md_state == MD_STATE_WAITING_FOR_HS1 || md_state == MD_STATE_WAITING_FOR_HS2) {
70 		dev_warn(port_private->dev, "Cannot write to %s port when md_state=%d\n",
71 			 port_conf->name, md_state);
72 		return -ENODEV;
73 	}
74 
75 	while (cur) {
76 		cloned = skb_clone(cur, GFP_KERNEL);
77 		cloned->len = skb_headlen(cur);
78 		ret = t7xx_port_send_skb(port_private, cloned, 0, 0);
79 		if (ret) {
80 			dev_kfree_skb(cloned);
81 			dev_err(port_private->dev, "Write error on %s port, %d\n",
82 				port_conf->name, ret);
83 			return cnt ? cnt + ret : ret;
84 		}
85 		cnt += cur->len;
86 		if (cur == skb)
87 			cur = skb_shinfo(skb)->frag_list;
88 		else
89 			cur = cur->next;
90 	}
91 
92 	dev_kfree_skb(skb);
93 	return 0;
94 }
95 
96 static const struct wwan_port_ops wwan_ops = {
97 	.start = t7xx_port_ctrl_start,
98 	.stop = t7xx_port_ctrl_stop,
99 	.tx = t7xx_port_ctrl_tx,
100 };
101 
102 static int t7xx_port_wwan_init(struct t7xx_port *port)
103 {
104 	port->rx_length_th = RX_QUEUE_MAXLEN;
105 	return 0;
106 }
107 
108 static void t7xx_port_wwan_uninit(struct t7xx_port *port)
109 {
110 	if (!port->wwan.wwan_port)
111 		return;
112 
113 	port->rx_length_th = 0;
114 	wwan_remove_port(port->wwan.wwan_port);
115 	port->wwan.wwan_port = NULL;
116 }
117 
118 static int t7xx_port_wwan_recv_skb(struct t7xx_port *port, struct sk_buff *skb)
119 {
120 	if (!atomic_read(&port->usage_cnt) || !port->chan_enable) {
121 		const struct t7xx_port_conf *port_conf = port->port_conf;
122 
123 		dev_kfree_skb_any(skb);
124 		dev_err_ratelimited(port->dev, "Port %s is not opened, drop packets\n",
125 				    port_conf->name);
126 		/* Dropping skb, caller should not access skb.*/
127 		return 0;
128 	}
129 
130 	wwan_port_rx(port->wwan.wwan_port, skb);
131 	return 0;
132 }
133 
134 static int t7xx_port_wwan_enable_chl(struct t7xx_port *port)
135 {
136 	spin_lock(&port->port_update_lock);
137 	port->chan_enable = true;
138 	spin_unlock(&port->port_update_lock);
139 
140 	return 0;
141 }
142 
143 static int t7xx_port_wwan_disable_chl(struct t7xx_port *port)
144 {
145 	spin_lock(&port->port_update_lock);
146 	port->chan_enable = false;
147 	spin_unlock(&port->port_update_lock);
148 
149 	return 0;
150 }
151 
152 static void t7xx_port_wwan_md_state_notify(struct t7xx_port *port, unsigned int state)
153 {
154 	const struct t7xx_port_conf *port_conf = port->port_conf;
155 	unsigned int header_len = sizeof(struct ccci_header);
156 	struct wwan_port_caps caps;
157 
158 	if (state != MD_STATE_READY)
159 		return;
160 
161 	if (!port->wwan.wwan_port) {
162 		caps.frag_len = CLDMA_MTU - header_len;
163 		caps.headroom_len = header_len;
164 		port->wwan.wwan_port = wwan_create_port(port->dev, port_conf->port_type,
165 							&wwan_ops, &caps, port);
166 		if (IS_ERR(port->wwan.wwan_port))
167 			dev_err(port->dev, "Unable to create WWWAN port %s", port_conf->name);
168 	}
169 }
170 
171 struct port_ops wwan_sub_port_ops = {
172 	.init = t7xx_port_wwan_init,
173 	.recv_skb = t7xx_port_wwan_recv_skb,
174 	.uninit = t7xx_port_wwan_uninit,
175 	.enable_chl = t7xx_port_wwan_enable_chl,
176 	.disable_chl = t7xx_port_wwan_disable_chl,
177 	.md_state_notify = t7xx_port_wwan_md_state_notify,
178 };
179