1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * u_ether.h -- interface to USB gadget "ethernet link" utilities
4  *
5  * Copyright (C) 2003-2005,2008 David Brownell
6  * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
7  * Copyright (C) 2008 Nokia Corporation
8  */
9 
10 #ifndef __U_ETHER_H
11 #define __U_ETHER_H
12 
13 #include <linux/err.h>
14 #include <linux/if_ether.h>
15 #include <linux/usb/composite.h>
16 #include <linux/usb/cdc.h>
17 #include <linux/netdevice.h>
18 
19 #define QMULT_DEFAULT 5
20 
21 /*
22  * dev_addr: initial value
23  * changed by "ifconfig usb0 hw ether xx:xx:xx:xx:xx:xx"
24  * host_addr: this address is invisible to ifconfig
25  */
26 #define USB_ETHERNET_MODULE_PARAMETERS() \
27 	static unsigned qmult = QMULT_DEFAULT;				\
28 	module_param(qmult, uint, S_IRUGO|S_IWUSR);			\
29 	MODULE_PARM_DESC(qmult, "queue length multiplier at high/super speed");\
30 									\
31 	static char *dev_addr;						\
32 	module_param(dev_addr, charp, S_IRUGO);				\
33 	MODULE_PARM_DESC(dev_addr, "Device Ethernet Address");		\
34 									\
35 	static char *host_addr;						\
36 	module_param(host_addr, charp, S_IRUGO);			\
37 	MODULE_PARM_DESC(host_addr, "Host Ethernet Address")
38 
39 struct eth_dev;
40 
41 /*
42  * This represents the USB side of an "ethernet" link, managed by a USB
43  * function which provides control and (maybe) framing.  Two functions
44  * in different configurations could share the same ethernet link/netdev,
45  * using different host interaction models.
46  *
47  * There is a current limitation that only one instance of this link may
48  * be present in any given configuration.  When that's a problem, network
49  * layer facilities can be used to package multiple logical links on this
50  * single "physical" one.
51  */
52 struct gether {
53 	struct usb_function		func;
54 
55 	/* updated by gether_{connect,disconnect} */
56 	struct eth_dev			*ioport;
57 
58 	/* endpoints handle full and/or high speeds */
59 	struct usb_ep			*in_ep;
60 	struct usb_ep			*out_ep;
61 
62 	bool				is_zlp_ok;
63 
64 	u16				cdc_filter;
65 
66 	/* hooks for added framing, as needed for RNDIS and EEM. */
67 	u32				header_len;
68 	/* NCM requires fixed size bundles */
69 	bool				is_fixed;
70 	u32				fixed_out_len;
71 	u32				fixed_in_len;
72 	bool				supports_multi_frame;
73 	struct sk_buff			*(*wrap)(struct gether *port,
74 						struct sk_buff *skb);
75 	int				(*unwrap)(struct gether *port,
76 						struct sk_buff *skb,
77 						struct sk_buff_head *list);
78 
79 	/* called on network open/close */
80 	void				(*open)(struct gether *);
81 	void				(*close)(struct gether *);
82 };
83 
84 #define	DEFAULT_FILTER	(USB_CDC_PACKET_TYPE_BROADCAST \
85 			|USB_CDC_PACKET_TYPE_ALL_MULTICAST \
86 			|USB_CDC_PACKET_TYPE_PROMISCUOUS \
87 			|USB_CDC_PACKET_TYPE_DIRECTED)
88 
89 /* variant of gether_setup that allows customizing network device name */
90 struct eth_dev *gether_setup_name(struct usb_gadget *g,
91 		const char *dev_addr, const char *host_addr,
92 		u8 ethaddr[ETH_ALEN], unsigned qmult, const char *netname);
93 
94 /* netdev setup/teardown as directed by the gadget driver */
95 /* gether_setup - initialize one ethernet-over-usb link
96  * @g: gadget to associated with these links
97  * @ethaddr: NULL, or a buffer in which the ethernet address of the
98  *	host side of the link is recorded
99  * Context: may sleep
100  *
101  * This sets up the single network link that may be exported by a
102  * gadget driver using this framework.  The link layer addresses are
103  * set up using module parameters.
104  *
105  * Returns a eth_dev pointer on success, or an ERR_PTR on failure
106  */
107 static inline struct eth_dev *gether_setup(struct usb_gadget *g,
108 		const char *dev_addr, const char *host_addr,
109 		u8 ethaddr[ETH_ALEN], unsigned qmult)
110 {
111 	return gether_setup_name(g, dev_addr, host_addr, ethaddr, qmult, "usb");
112 }
113 
114 /*
115  * variant of gether_setup_default that allows customizing
116  * network device name
117  */
118 struct net_device *gether_setup_name_default(const char *netname);
119 
120 /*
121  * gether_register_netdev - register the net device
122  * @net: net device to register
123  *
124  * Registers the net device associated with this ethernet-over-usb link
125  *
126  */
127 int gether_register_netdev(struct net_device *net);
128 
129 /* gether_setup_default - initialize one ethernet-over-usb link
130  * Context: may sleep
131  *
132  * This sets up the single network link that may be exported by a
133  * gadget driver using this framework.  The link layer addresses
134  * are set to random values.
135  *
136  * Returns negative errno, or zero on success
137  */
138 static inline struct net_device *gether_setup_default(void)
139 {
140 	return gether_setup_name_default("usb");
141 }
142 
143 /**
144  * gether_set_gadget - initialize one ethernet-over-usb link with a gadget
145  * @net: device representing this link
146  * @g: the gadget to initialize with
147  *
148  * This associates one ethernet-over-usb link with a gadget.
149  */
150 void gether_set_gadget(struct net_device *net, struct usb_gadget *g);
151 
152 /**
153  * gether_set_dev_addr - initialize an ethernet-over-usb link with eth address
154  * @net: device representing this link
155  * @dev_addr: eth address of this device
156  *
157  * This sets the device-side Ethernet address of this ethernet-over-usb link
158  * if dev_addr is correct.
159  * Returns negative errno if the new address is incorrect.
160  */
161 int gether_set_dev_addr(struct net_device *net, const char *dev_addr);
162 
163 /**
164  * gether_get_dev_addr - get an ethernet-over-usb link eth address
165  * @net: device representing this link
166  * @dev_addr: place to store device's eth address
167  * @len: length of the @dev_addr buffer
168  *
169  * This gets the device-side Ethernet address of this ethernet-over-usb link.
170  * Returns zero on success, else negative errno.
171  */
172 int gether_get_dev_addr(struct net_device *net, char *dev_addr, int len);
173 
174 /**
175  * gether_set_host_addr - initialize an ethernet-over-usb link with host address
176  * @net: device representing this link
177  * @host_addr: eth address of the host
178  *
179  * This sets the host-side Ethernet address of this ethernet-over-usb link
180  * if host_addr is correct.
181  * Returns negative errno if the new address is incorrect.
182  */
183 int gether_set_host_addr(struct net_device *net, const char *host_addr);
184 
185 /**
186  * gether_get_host_addr - get an ethernet-over-usb link host address
187  * @net: device representing this link
188  * @host_addr: place to store eth address of the host
189  * @len: length of the @host_addr buffer
190  *
191  * This gets the host-side Ethernet address of this ethernet-over-usb link.
192  * Returns zero on success, else negative errno.
193  */
194 int gether_get_host_addr(struct net_device *net, char *host_addr, int len);
195 
196 /**
197  * gether_get_host_addr_cdc - get an ethernet-over-usb link host address
198  * @net: device representing this link
199  * @host_addr: place to store eth address of the host
200  * @len: length of the @host_addr buffer
201  *
202  * This gets the CDC formatted host-side Ethernet address of this
203  * ethernet-over-usb link.
204  * Returns zero on success, else negative errno.
205  */
206 int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len);
207 
208 /**
209  * gether_get_host_addr_u8 - get an ethernet-over-usb link host address
210  * @net: device representing this link
211  * @host_mac: place to store the eth address of the host
212  *
213  * This gets the binary formatted host-side Ethernet address of this
214  * ethernet-over-usb link.
215  */
216 void gether_get_host_addr_u8(struct net_device *net, u8 host_mac[ETH_ALEN]);
217 
218 /**
219  * gether_set_qmult - initialize an ethernet-over-usb link with a multiplier
220  * @net: device representing this link
221  * @qmult: queue multiplier
222  *
223  * This sets the queue length multiplier of this ethernet-over-usb link.
224  * For higher speeds use longer queues.
225  */
226 void gether_set_qmult(struct net_device *net, unsigned qmult);
227 
228 /**
229  * gether_get_qmult - get an ethernet-over-usb link multiplier
230  * @net: device representing this link
231  *
232  * This gets the queue length multiplier of this ethernet-over-usb link.
233  */
234 unsigned gether_get_qmult(struct net_device *net);
235 
236 /**
237  * gether_get_ifname - get an ethernet-over-usb link interface name
238  * @net: device representing this link
239  * @name: place to store the interface name
240  * @len: length of the @name buffer
241  *
242  * This gets the interface name of this ethernet-over-usb link.
243  * Returns zero on success, else negative errno.
244  */
245 int gether_get_ifname(struct net_device *net, char *name, int len);
246 
247 void gether_cleanup(struct eth_dev *dev);
248 
249 /* connect/disconnect is handled by individual functions */
250 struct net_device *gether_connect(struct gether *);
251 void gether_disconnect(struct gether *);
252 
253 /* Some controllers can't support CDC Ethernet (ECM) ... */
254 static inline bool can_support_ecm(struct usb_gadget *gadget)
255 {
256 	if (!gadget_is_altset_supported(gadget))
257 		return false;
258 
259 	/* Everything else is *presumably* fine ... but this is a bit
260 	 * chancy, so be **CERTAIN** there are no hardware issues with
261 	 * your controller.  Add it above if it can't handle CDC.
262 	 */
263 	return true;
264 }
265 
266 #endif /* __U_ETHER_H */
267