1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2021 - 2022 Intel Corporation
4  */
5 
6 #ifndef __iwl_mei_h__
7 #define __iwl_mei_h__
8 
9 #include <linux/if_ether.h>
10 #include <linux/skbuff.h>
11 #include <linux/ieee80211.h>
12 
13 /**
14  * DOC: Introduction
15  *
16  * iwlmei is the kernel module that is in charge of the communication between
17  * the iwlwifi driver and the CSME firmware's WLAN driver. This communication
18  * uses the SAP protocol defined in another file.
19  * iwlwifi can request or release ownership on the WiFi device through iwlmei.
20  * iwlmei may notify iwlwifi about certain events: what filter iwlwifi should
21  * use to passthrough inbound packets to the CSME firmware for example. iwlmei
22  * may also use iwlwifi to send traffic. This means that we need communication
23  * from iwlmei to iwlwifi and the other way around.
24  */
25 
26 /**
27  * DOC: Life cycle
28  *
29  * iwlmei exports symbols that are needed by iwlwifi so that iwlmei will always
30  * be loaded when iwlwifi is alive. iwlwifi registers itself to iwlmei and
31  * provides the pointers to the functions that iwlmei calls whenever needed.
32  * iwlwifi calls iwlmei through direct and context-free function calls.
33  * It is assumed that only one device is accessible to the CSME firmware and
34  * under the scope of iwlmei so that it is valid not to have any context passed
35  * to iwlmei's functions.
36  *
37  * There are cases in which iwlmei can't access the CSME firmware, because the
38  * CSME firmware is undergoing a reset, or the mei bus decided to unbind the
39  * device. In those cases, iwlmei will need not to send requests over the mei
40  * bus. Instead, it needs to cache the requests from iwlwifi and fulfill them
41  * when the mei bus is available again.
42  *
43  * iwlmei can call iwlwifi as long as iwlwifi is registered to iwlmei. When
44  * iwlwifi goes down (the PCI device is unbound, or the iwlwifi is unloaded)
45  * iwlwifi needs to unregister from iwlmei.
46  */
47 
48 /**
49  * DOC: Memory layout
50  *
51  * Since iwlwifi calls iwlmei without any context, iwlmei needs to hold a
52  * global pointer to its data (which is in the mei client device's private
53  * data area). If there was no bind on the mei bus, this pointer is NULL and
54  * iwlmei knows not access to the CSME firmware upon requests from iwlwifi.
55  *
56  * iwlmei needs to cache requests from iwlwifi when there is no mei client
57  * device available (when iwlmei has been removed from the mei bus). In this
58  * case, all iwlmei's data that resides in the mei client device's private data
59  * area is unavailable. For this specific case, a separate caching area is
60  * needed.
61  */
62 
63 /**
64  * DOC: Concurrency
65  *
66  * iwlwifi can call iwlmei at any time. iwlmei will take care to synchronize
67  * the calls from iwlwifi with its internal flows. iwlwifi must not call iwlmei
68  * in flows that cannot sleep. Moreover, iwlwifi must not call iwlmei in flows
69  * that originated from iwlmei.
70  */
71 
72 /**
73  * DOC: Probe and remove from mei bus driver
74  *
75  * When the mei bus driver enumerates its devices, it calls the iwlmei's probe
76  * function which will send the %SAP_ME_MSG_START message. The probe completes
77  * before the response (%SAP_ME_MSG_START_OK) is received. This response will
78  * be handle by the Rx path. Once it arrives, the connection to the CSME
79  * firmware is considered established and iwlwifi's requests can be treated
80  * against the CSME firmware.
81  *
82  * When the mei bus driver removes the device, iwlmei loses all the data that
83  * was attached to the mei client device. It clears the global pointer to the
84  * mei client device since it is not available anymore. This will cause all the
85  * requests coming from iwlwifi to be cached. This flow takes the global mutex
86  * to be synchronized with all the requests coming from iwlwifi.
87  */
88 
89 /**
90  * DOC: Driver load when CSME owns the device
91  *
92  * When the driver (iwlwifi) is loaded while CSME owns the device,
93  * it'll ask CSME to release the device through HW registers. CSME
94  * will release the device only in the case that there is no connection
95  * through the mei bus. If there is a mei bus connection, CSME will refuse
96  * to release the ownership on the device through the HW registers. In that
97  * case, iwlwifi must first request ownership using the SAP protocol.
98  *
99  * Once iwlwifi will request ownership through the SAP protocol, CSME will
100  * grant the ownership on the device through the HW registers as well.
101  * In order to request ownership over SAP, we first need to have an interface
102  * which means that we need to register to mac80211.
103  * This can't happen before we get the NVM that contains all the capabilities
104  * of the device. Reading the NVM usually requires the load the firmware, but
105  * this is impossible as long as we don't have ownership on the device.
106  * In order to solve this chicken and egg problem, the host driver can get
107  * the NVM through CSME which owns the device. It can send
108  * %SAP_MSG_NOTIF_GET_NVM, which will be replied by %SAP_MSG_NOTIF_NVM with
109  * the NVM's content that the host driver needs.
110  */
111 
112 /**
113  * DOC: CSME behavior regarding the ownership requests
114  *
115  * The ownership requests from the host can come in two different ways:
116  *  - the HW registers in iwl_pcie_set_hw_ready
117  *  - using the Software Arbitration Protocol (SAP)
118  *
119  * The host can ask CSME who owns the device with %SAP_MSG_NOTIF_WHO_OWNS_NIC,
120  * and it can request ownership with %SAP_MSG_NOTIF_HOST_ASKS_FOR_NIC_OWNERSHIP.
121  * The host will first use %SAP_MSG_NOTIF_WHO_OWNS_NIC to know what state
122  * CSME is in. In case CSME thinks it owns the device, the host can ask for
123  * ownership with %SAP_MSG_NOTIF_HOST_ASKS_FOR_NIC_OWNERSHIP.
124  *
125  * Here the table that describes CSME's behavior upon ownership request:
126  *
127  * +-------------------+------------+--------------+-----------------------------+------------+
128  * | State             | HW reg bit | Reply for    | Event                       | HW reg bit |
129  * |                   | before     | WHO_OWNS_NIC |                             | after      |
130  * +===================+============+==============+=============================+============+
131  * | WiAMT not         | 0          | Host         | HW register or              | 0          |
132  * | operational       | Host owner |              | HOST_ASKS_FOR_NIC_OWNERSHIP | Host owner |
133  * +-------------------+------------+--------------+-----------------------------+------------+
134  * | Operational &     | 1          | N/A          | HW register                 | 0          |
135  * | SAP down &        | CSME owner |              |                             | Host owner |
136  * | no session active |            |              |                             |            |
137  * +-------------------+------------+--------------+-----------------------------+------------+
138  * | Operational &     | 1          | CSME         | HW register                 | 1          |
139  * | SAP up            | CSME owner |              |                             | CSME owner |
140  * +-------------------+------------+--------------+-----------------------------+------------+
141  * | Operational &     | 1          | CSME         | HOST_ASKS_FOR_NIC_OWNERSHIP | 0          |
142  * | SAP up            | CSME owner |              |                             | Host owner |
143  * +-------------------+------------+--------------+-----------------------------+------------+
144  */
145 
146 /**
147  * DOC: Driver load when CSME is associated and a session is active
148  *
149  * A "session" is active when CSME is associated to an access point and the
150  * link is used to attach a remote driver or to control the system remotely.
151  * When a session is active, we want to make sure it won't disconnect when we
152  * take ownership on the device.
153  * In this case, the driver can get the device, but it'll need to make
154  * sure that it'll connect to the exact same AP (same BSSID).
155  * In order to do so, CSME will send the connection parameters through
156  * SAP and then the host can check if it can connect to this same AP.
157  * If yes, it can request ownership through SAP and connect quickly without
158  * scanning all the channels, but just probing the AP on the channel that
159  * CSME was connected to.
160  * In order to signal this specific scenario to iwlwifi, iwlmei will
161  * immediately require iwlwifi to report RF-Kill to the network stack. This
162  * RF-Kill will prevent the stack from getting the device, and it has a reason
163  * that tells the userspace that the device is in RF-Kill because it is not
164  * owned by the host. Once the userspace has configured the right profile,
165  * it'll be able to let iwlmei know that it can request ownership over SAP
166  * which will remove the RF-Kill, and finally allow the host to connect.
167  * The host has then 3 seconds to connect (including DHCP). Had the host
168  * failed to connect within those 3 seconds, CSME will take the device back.
169  */
170 
171 /**
172  * DOC: Datapath
173  *
174  * CSME can transmit packets, through the netdev that it gets from the wifi
175  * driver. It'll send packet in the 802.3 format and simply call
176  * dev_queue_xmit.
177  *
178  * For Rx, iwlmei registers a Rx handler that it attaches to the netdev. iwlmei
179  * may catch packets and send them to CSME, it can then either drop them so
180  * that they are invisible to user space, or let them go the user space.
181  *
182  * Packets transmitted by the user space do not need to be forwarded to CSME
183  * with the exception of the DHCP request. In order to know what IP is used
184  * by the user space, CSME needs to get the DHCP request. See
185  * iwl_mei_tx_copy_to_csme().
186  */
187 
188 /**
189  * enum iwl_mei_nvm_caps - capabilities for MEI NVM
190  * @MEI_NVM_CAPS_LARI_SUPPORT: Lari is supported
191  * @MEI_NVM_CAPS_11AX_SUPPORT: 11AX is supported
192  */
193 enum iwl_mei_nvm_caps {
194 	MEI_NVM_CAPS_LARI_SUPPORT	= BIT(0),
195 	MEI_NVM_CAPS_11AX_SUPPORT	= BIT(1),
196 };
197 
198 /**
199  * struct iwl_mei_nvm - used to pass the NVM from CSME
200  * @hw_addr: The MAC address
201  * @n_hw_addrs: The number of MAC addresses
202  * @reserved: For alignment.
203  * @radio_cfg: The radio configuration.
204  * @caps: See &enum iwl_mei_nvm_caps.
205  * @nvm_version: The version of the NVM.
206  * @channels: The data for each channel.
207  *
208  * If a field is added, it must correspond to the SAP structure.
209  */
210 struct iwl_mei_nvm {
211 	u8 hw_addr[ETH_ALEN];
212 	u8 n_hw_addrs;
213 	u8 reserved;
214 	u32 radio_cfg;
215 	u32 caps;
216 	u32 nvm_version;
217 	u32 channels[110];
218 };
219 
220 /**
221  * enum iwl_mei_pairwise_cipher - cipher for UCAST key
222  * @IWL_MEI_CIPHER_NONE: none
223  * @IWL_MEI_CIPHER_TKIP: tkip
224  * @IWL_MEI_CIPHER_CCMP: ccmp
225  * @IWL_MEI_CIPHER_GCMP: gcmp
226  * @IWL_MEI_CIPHER_GCMP_256: gcmp 256
227  *
228  * Note that those values are dictated by the CSME firmware API (see sap.h)
229  */
230 enum iwl_mei_pairwise_cipher {
231 	IWL_MEI_CIPHER_NONE	= 0,
232 	IWL_MEI_CIPHER_TKIP	= 2,
233 	IWL_MEI_CIPHER_CCMP	= 4,
234 	IWL_MEI_CIPHER_GCMP	= 8,
235 	IWL_MEI_CIPHER_GCMP_256 = 9,
236 };
237 
238 /**
239  * enum iwl_mei_akm_auth - a combination of AKM and AUTH method
240  * @IWL_MEI_AKM_AUTH_OPEN: No encryption
241  * @IWL_MEI_AKM_AUTH_RSNA: 1X profile
242  * @IWL_MEI_AKM_AUTH_RSNA_PSK: PSK profile
243  * @IWL_MEI_AKM_AUTH_SAE: SAE profile
244  *
245  * Note that those values are dictated by the CSME firmware API (see sap.h)
246  */
247 enum iwl_mei_akm_auth {
248 	IWL_MEI_AKM_AUTH_OPEN		= 0,
249 	IWL_MEI_AKM_AUTH_RSNA		= 6,
250 	IWL_MEI_AKM_AUTH_RSNA_PSK	= 7,
251 	IWL_MEI_AKM_AUTH_SAE		= 9,
252 };
253 
254 /**
255  * struct iwl_mei_conn_info - connection info
256  * @lp_state: link protection state
257  * @auth_mode: authentication mode
258  * @ssid_len: the length of SSID
259  * @ssid: the SSID
260  * @pairwise_cipher: the cipher used for unicast packets
261  * @channel: the associated channel
262  * @band: the associated band
263  * @bssid: the BSSID
264  */
265 struct iwl_mei_conn_info {
266 	u8 lp_state;
267 	u8 auth_mode;
268 	u8 ssid_len;
269 	u8 channel;
270 	u8 band;
271 	u8 pairwise_cipher;
272 	u8 bssid[ETH_ALEN];
273 	u8 ssid[IEEE80211_MAX_SSID_LEN];
274 };
275 
276 /**
277  * struct iwl_mei_colloc_info - collocated AP info
278  * @channel: the channel of the collocated AP
279  * @bssid: the BSSID of the collocated AP
280  */
281 struct iwl_mei_colloc_info {
282 	u8 channel;
283 	u8 bssid[ETH_ALEN];
284 };
285 
286 /*
287  * struct iwl_mei_ops - driver's operations called by iwlmei
288  * Operations will not be called more than once concurrently.
289  * It's not allowed to call iwlmei functions from this context.
290  *
291  * @me_conn_status: provide information about CSME's current connection.
292  * @rfkill: called when the wifi driver should report a change in the rfkill
293  *	status.
294  * @roaming_forbidden: indicates whether roaming is forbidden.
295  * @sap_connected: indicate that SAP is now connected. Will be called in case
296  *	the wifi driver registered to iwlmei before SAP connection succeeded or
297  *	when the SAP connection is re-established.
298  * @nic_stolen: this means that device is no longer available. The device can
299  *	still be used until the callback returns.
300  */
301 struct iwl_mei_ops {
302 	void (*me_conn_status)(void *priv,
303 			       const struct iwl_mei_conn_info *conn_info);
304 	void (*rfkill)(void *priv, bool blocked, bool csme_taking_ownership);
305 	void (*roaming_forbidden)(void *priv, bool forbidden);
306 	void (*sap_connected)(void *priv);
307 	void (*nic_stolen)(void *priv);
308 };
309 
310 #if IS_ENABLED(CONFIG_IWLMEI)
311 
312 /**
313  * iwl_mei_is_connected() - is the connection to the CSME firmware established?
314  *
315  * Return: true if we have a SAP connection
316  */
317 bool iwl_mei_is_connected(void);
318 
319 /**
320  * iwl_mei_get_nvm() - returns the NVM for the device
321  *
322  * It is the caller's responsibility to free the memory returned
323  * by this function.
324  * This function blocks (sleeps) until the NVM is ready.
325  *
326  * Return: the NVM as received from CSME
327  */
328 struct iwl_mei_nvm *iwl_mei_get_nvm(void);
329 
330 /**
331  * iwl_mei_get_ownership() - request ownership
332  *
333  * This function blocks until ownership is granted or timeout expired.
334  *
335  * Return: 0 in case we could get ownership on the device
336  */
337 int iwl_mei_get_ownership(void);
338 
339 /**
340  * iwl_mei_set_rfkill_state() - set SW and HW RF kill states
341  * @hw_rfkill: HW RF kill state.
342  * @sw_rfkill: SW RF kill state.
343  *
344  * This function must be called when SW RF kill is issued by the user.
345  */
346 void iwl_mei_set_rfkill_state(bool hw_rfkill, bool sw_rfkill);
347 
348 /**
349  * iwl_mei_set_nic_info() - set mac address
350  * @mac_address: mac address to set
351  * @nvm_address: NVM mac address to set
352  *
353  * This function must be called upon mac address change.
354  */
355 void iwl_mei_set_nic_info(const u8 *mac_address, const u8 *nvm_address);
356 
357 /**
358  * iwl_mei_set_country_code() - set new country code
359  * @mcc: the new applied MCC
360  *
361  * This function must be called upon country code update
362  */
363 void iwl_mei_set_country_code(u16 mcc);
364 
365 /**
366  * iwl_mei_set_power_limit() - set TX power limit
367  * @power_limit: pointer to an array of 10 elements (le16) represents the power
368  * restrictions per chain.
369  *
370  * This function must be called upon power restrictions change
371  */
372 void iwl_mei_set_power_limit(const __le16 *power_limit);
373 
374 /**
375  * iwl_mei_register() - register the wifi driver to iwlmei
376  * @priv: a pointer to the wifi driver's context. Cannot be NULL.
377  * @ops: the ops structure.
378  *
379  * Return: 0 unless something went wrong. It is illegal to call any
380  * other API function before this function is called and succeeds.
381  *
382  * Only one wifi driver instance (wifi device instance really)
383  * can register at a time.
384  */
385 int iwl_mei_register(void *priv, const struct iwl_mei_ops *ops);
386 
387 /**
388  * iwl_mei_start_unregister() - unregister the wifi driver from iwlmei
389  *
390  * From this point on, iwlmei will not used the callbacks provided by
391  * the driver, but the device is still usable.
392  */
393 void iwl_mei_start_unregister(void);
394 
395 /**
396  * iwl_mei_unregister_complete() - complete the unregistration
397  *
398  * Must be called after iwl_mei_start_unregister. When this function returns,
399  * the device is owned by CSME.
400  */
401 void iwl_mei_unregister_complete(void);
402 
403 /**
404  * iwl_mei_set_netdev() - sets the netdev for Tx / Rx.
405  * @netdev: the net_device
406  *
407  * The caller should set the netdev to a non-NULL value when the
408  * interface is added. Packets might be sent to the driver immediately
409  * afterwards.
410  * The caller should set the netdev to NULL when the interface is removed.
411  * This function will call synchronize_net() after setting the netdev to NULL.
412  * Only when this function returns, can the caller assume that iwlmei will
413  * no longer inject packets into the netdev's Tx path.
414  *
415  * Context: This function can sleep and assumes rtnl_lock is taken.
416  * The netdev must be set to NULL before iwl_mei_start_unregister() is called.
417  */
418 void iwl_mei_set_netdev(struct net_device *netdev);
419 
420 /**
421  * iwl_mei_tx_copy_to_csme() - must be called for each packet sent by
422  * the wifi driver.
423  * @skb: the skb sent
424  * @ivlen: the size of the IV that needs to be skipped after the MAC and
425  *	before the SNAP header.
426  *
427  * This function doesn't take any lock, it simply tries to catch DHCP
428  * packets sent by the wifi driver. If the packet is a DHCP packet, it
429  * will send it to CSME. This function must not be called for virtual
430  * interfaces that are not monitored by CSME, meaning it must be called
431  * only for packets transmitted by the netdevice that was registered
432  * with iwl_mei_set_netdev().
433  */
434 void iwl_mei_tx_copy_to_csme(struct sk_buff *skb, unsigned int ivlen);
435 
436 /**
437  * iwl_mei_host_associated() - must be called when iwlwifi associated.
438  * @conn_info: pointer to the connection info structure.
439  * @colloc_info: pointer to the collocated AP info. This is relevant only in
440  *	case of UHB associated AP, otherwise set to NULL.
441  */
442 void iwl_mei_host_associated(const struct iwl_mei_conn_info *conn_info,
443 			     const struct iwl_mei_colloc_info *colloc_info);
444 
445 /**
446  * iwl_mei_host_disassociated() - must be called when iwlwifi disassociated.
447  */
448 void iwl_mei_host_disassociated(void);
449 
450 /**
451  * iwl_mei_device_state() - must be called when the device changes up/down state
452  * @up: true if the device is up, false otherwise.
453  */
454 void iwl_mei_device_state(bool up);
455 
456 /**
457  * iwl_mei_pldr_req() - must be called before loading the fw
458  *
459  * Return: 0 if the PLDR flow was successful and the fw can be loaded, negative
460  *	value otherwise.
461  */
462 int iwl_mei_pldr_req(void);
463 
464 /**
465  * iwl_mei_alive_notif() - must be called when alive notificaiton is received
466  * @success: true if received alive notification, false if waiting for the
467  *	notificaiton timed out.
468  */
469 void iwl_mei_alive_notif(bool success);
470 
471 #else
472 
473 static inline bool iwl_mei_is_connected(void)
474 { return false; }
475 
476 static inline struct iwl_mei_nvm *iwl_mei_get_nvm(void)
477 { return NULL; }
478 
479 static inline int iwl_mei_get_ownership(void)
480 { return 0; }
481 
482 static inline void iwl_mei_set_rfkill_state(bool hw_rfkill, bool sw_rfkill)
483 {}
484 
485 static inline void iwl_mei_set_nic_info(const u8 *mac_address, const u8 *nvm_address)
486 {}
487 
488 static inline void iwl_mei_set_country_code(u16 mcc)
489 {}
490 
491 static inline void iwl_mei_set_power_limit(__le16 *power_limit)
492 {}
493 
494 static inline int iwl_mei_register(void *priv,
495 				   const struct iwl_mei_ops *ops)
496 { return 0; }
497 
498 static inline void iwl_mei_start_unregister(void)
499 {}
500 
501 static inline void iwl_mei_unregister_complete(void)
502 {}
503 
504 static inline void iwl_mei_set_netdev(struct net_device *netdev)
505 {}
506 
507 static inline void iwl_mei_tx_copy_to_csme(struct sk_buff *skb,
508 					   unsigned int ivlen)
509 {}
510 
511 static inline void iwl_mei_host_associated(const struct iwl_mei_conn_info *conn_info,
512 					   const struct iwl_mei_colloc_info *colloc_info)
513 {}
514 
515 static inline void iwl_mei_host_disassociated(void)
516 {}
517 
518 static inline void iwl_mei_device_state(bool up)
519 {}
520 
521 static inline int iwl_mei_pldr_req(void)
522 { return 0; }
523 
524 static inline void iwl_mei_alive_notif(bool success)
525 {}
526 
527 #endif /* CONFIG_IWLMEI */
528 
529 #endif /* __iwl_mei_h__ */
530