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  Bj��rn 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 */
29struct 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
37static 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
52static 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
65static 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
112err:
113	return ret;
114}
115
116static 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
129static 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
153error:
154	return ret;
155}
156
157static 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);
178err:
179	return ret;
180}
181
182static 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
192static 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};
211MODULE_DEVICE_TABLE(usb, huawei_cdc_ncm_devs);
212
213static 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};
224module_usb_driver(huawei_cdc_ncm_driver);
225MODULE_AUTHOR("Enrico Mioso <mrkiko.rs@gmail.com>");
226MODULE_DESCRIPTION("USB CDC NCM host driver with encapsulated protocol support");
227MODULE_LICENSE("GPL");
228