1 // SPDX-License-Identifier: GPL-2.0-only
2 /* huawei_cdc_ncm.c - handles Huawei devices using the CDC NCM protocol as
3 * transport layer.
4 * Copyright (C) 2013 Enrico Mioso <mrkiko.rs@gmail.com>
5 *
6 * ABSTRACT:
7 * This driver handles devices resembling the CDC NCM standard, but
8 * encapsulating another protocol inside it. An example are some Huawei 3G
9 * devices, exposing an embedded AT channel where you can set up the NCM
10 * connection.
11 * This code has been heavily inspired by the cdc_mbim.c driver, which is
12 * Copyright (c) 2012 Smith Micro Software, Inc.
13 * Copyright (c) 2012 Bjørn Mork <bjorn@mork.no>
14 */
15
16 #include <linux/module.h>
17 #include <linux/netdevice.h>
18 #include <linux/ethtool.h>
19 #include <linux/if_vlan.h>
20 #include <linux/ip.h>
21 #include <linux/mii.h>
22 #include <linux/usb.h>
23 #include <linux/usb/cdc.h>
24 #include <linux/usb/usbnet.h>
25 #include <linux/usb/cdc-wdm.h>
26 #include <linux/usb/cdc_ncm.h>
27
28 /* Driver data */
29 struct huawei_cdc_ncm_state {
30 struct cdc_ncm_ctx *ctx;
31 atomic_t pmcount;
32 struct usb_driver *subdriver;
33 struct usb_interface *control;
34 struct usb_interface *data;
35 };
36
huawei_cdc_ncm_manage_power(struct usbnet * usbnet_dev,int on)37 static int huawei_cdc_ncm_manage_power(struct usbnet *usbnet_dev, int on)
38 {
39 struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
40 int rv;
41
42 if ((on && atomic_add_return(1, &drvstate->pmcount) == 1) ||
43 (!on && atomic_dec_and_test(&drvstate->pmcount))) {
44 rv = usb_autopm_get_interface(usbnet_dev->intf);
45 usbnet_dev->intf->needs_remote_wakeup = on;
46 if (!rv)
47 usb_autopm_put_interface(usbnet_dev->intf);
48 }
49 return 0;
50 }
51
huawei_cdc_ncm_wdm_manage_power(struct usb_interface * intf,int status)52 static int huawei_cdc_ncm_wdm_manage_power(struct usb_interface *intf,
53 int status)
54 {
55 struct usbnet *usbnet_dev = usb_get_intfdata(intf);
56
57 /* can be called while disconnecting */
58 if (!usbnet_dev)
59 return 0;
60
61 return huawei_cdc_ncm_manage_power(usbnet_dev, status);
62 }
63
64
huawei_cdc_ncm_bind(struct usbnet * usbnet_dev,struct usb_interface * intf)65 static int huawei_cdc_ncm_bind(struct usbnet *usbnet_dev,
66 struct usb_interface *intf)
67 {
68 struct cdc_ncm_ctx *ctx;
69 struct usb_driver *subdriver = ERR_PTR(-ENODEV);
70 int ret;
71 struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
72 int drvflags = 0;
73
74 /* altsetting should always be 1 for NCM devices - so we hard-coded
75 * it here. Some huawei devices will need the NDP part of the NCM package to
76 * be at the end of the frame.
77 */
78 drvflags |= CDC_NCM_FLAG_NDP_TO_END;
79
80 /* For many Huawei devices the NTB32 mode is the default and the best mode
81 * they work with. Huawei E5785 and E5885 devices refuse to work in NTB16 mode at all.
82 */
83 drvflags |= CDC_NCM_FLAG_PREFER_NTB32;
84
85 ret = cdc_ncm_bind_common(usbnet_dev, intf, 1, drvflags);
86 if (ret)
87 goto err;
88
89 ctx = drvstate->ctx;
90
91 if (usbnet_dev->status)
92 /* The wMaxCommand buffer must be big enough to hold
93 * any message from the modem. Experience has shown
94 * that some replies are more than 256 bytes long
95 */
96 subdriver = usb_cdc_wdm_register(ctx->control,
97 &usbnet_dev->status->desc,
98 1024, /* wMaxCommand */
99 WWAN_PORT_AT,
100 huawei_cdc_ncm_wdm_manage_power);
101 if (IS_ERR(subdriver)) {
102 ret = PTR_ERR(subdriver);
103 cdc_ncm_unbind(usbnet_dev, intf);
104 goto err;
105 }
106
107 /* Prevent usbnet from using the status descriptor */
108 usbnet_dev->status = NULL;
109
110 drvstate->subdriver = subdriver;
111
112 err:
113 return ret;
114 }
115
huawei_cdc_ncm_unbind(struct usbnet * usbnet_dev,struct usb_interface * intf)116 static void huawei_cdc_ncm_unbind(struct usbnet *usbnet_dev,
117 struct usb_interface *intf)
118 {
119 struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
120 struct cdc_ncm_ctx *ctx = drvstate->ctx;
121
122 if (drvstate->subdriver && drvstate->subdriver->disconnect)
123 drvstate->subdriver->disconnect(ctx->control);
124 drvstate->subdriver = NULL;
125
126 cdc_ncm_unbind(usbnet_dev, intf);
127 }
128
huawei_cdc_ncm_suspend(struct usb_interface * intf,pm_message_t message)129 static int huawei_cdc_ncm_suspend(struct usb_interface *intf,
130 pm_message_t message)
131 {
132 int ret = 0;
133 struct usbnet *usbnet_dev = usb_get_intfdata(intf);
134 struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
135 struct cdc_ncm_ctx *ctx = drvstate->ctx;
136
137 if (ctx == NULL) {
138 ret = -ENODEV;
139 goto error;
140 }
141
142 ret = usbnet_suspend(intf, message);
143 if (ret < 0)
144 goto error;
145
146 if (intf == ctx->control &&
147 drvstate->subdriver &&
148 drvstate->subdriver->suspend)
149 ret = drvstate->subdriver->suspend(intf, message);
150 if (ret < 0)
151 usbnet_resume(intf);
152
153 error:
154 return ret;
155 }
156
huawei_cdc_ncm_resume(struct usb_interface * intf)157 static int huawei_cdc_ncm_resume(struct usb_interface *intf)
158 {
159 int ret = 0;
160 struct usbnet *usbnet_dev = usb_get_intfdata(intf);
161 struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
162 bool callsub;
163 struct cdc_ncm_ctx *ctx = drvstate->ctx;
164
165 /* should we call subdriver's resume function? */
166 callsub =
167 (intf == ctx->control &&
168 drvstate->subdriver &&
169 drvstate->subdriver->resume);
170
171 if (callsub)
172 ret = drvstate->subdriver->resume(intf);
173 if (ret < 0)
174 goto err;
175 ret = usbnet_resume(intf);
176 if (ret < 0 && callsub)
177 drvstate->subdriver->suspend(intf, PMSG_SUSPEND);
178 err:
179 return ret;
180 }
181
182 static const struct driver_info huawei_cdc_ncm_info = {
183 .description = "Huawei CDC NCM device",
184 .flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN,
185 .bind = huawei_cdc_ncm_bind,
186 .unbind = huawei_cdc_ncm_unbind,
187 .manage_power = huawei_cdc_ncm_manage_power,
188 .rx_fixup = cdc_ncm_rx_fixup,
189 .tx_fixup = cdc_ncm_tx_fixup,
190 };
191
192 static const struct usb_device_id huawei_cdc_ncm_devs[] = {
193 /* Huawei NCM devices disguised as vendor specific */
194 { USB_VENDOR_AND_INTERFACE_INFO(0x12d1, 0xff, 0x02, 0x16),
195 .driver_info = (unsigned long)&huawei_cdc_ncm_info,
196 },
197 { USB_VENDOR_AND_INTERFACE_INFO(0x12d1, 0xff, 0x02, 0x46),
198 .driver_info = (unsigned long)&huawei_cdc_ncm_info,
199 },
200 { USB_VENDOR_AND_INTERFACE_INFO(0x12d1, 0xff, 0x02, 0x76),
201 .driver_info = (unsigned long)&huawei_cdc_ncm_info,
202 },
203 { USB_VENDOR_AND_INTERFACE_INFO(0x12d1, 0xff, 0x03, 0x16),
204 .driver_info = (unsigned long)&huawei_cdc_ncm_info,
205 },
206
207 /* Terminating entry */
208 {
209 },
210 };
211 MODULE_DEVICE_TABLE(usb, huawei_cdc_ncm_devs);
212
213 static struct usb_driver huawei_cdc_ncm_driver = {
214 .name = "huawei_cdc_ncm",
215 .id_table = huawei_cdc_ncm_devs,
216 .probe = usbnet_probe,
217 .disconnect = usbnet_disconnect,
218 .suspend = huawei_cdc_ncm_suspend,
219 .resume = huawei_cdc_ncm_resume,
220 .reset_resume = huawei_cdc_ncm_resume,
221 .supports_autosuspend = 1,
222 .disable_hub_initiated_lpm = 1,
223 };
224 module_usb_driver(huawei_cdc_ncm_driver);
225 MODULE_AUTHOR("Enrico Mioso <mrkiko.rs@gmail.com>");
226 MODULE_DESCRIPTION("USB CDC NCM host driver with encapsulated protocol support");
227 MODULE_LICENSE("GPL");
228