1/*
2 * MEI Library for mei bus nfc device access
3 *
4 * Copyright (C) 2013  Intel Corporation. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, see <http://www.gnu.org/licenses/>.
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/module.h>
22#include <linux/slab.h>
23#include <linux/nfc.h>
24
25#include "mei_phy.h"
26
27struct mei_nfc_hdr {
28	u8 cmd;
29	u8 status;
30	u16 req_id;
31	u32 reserved;
32	u16 data_size;
33} __packed;
34
35struct mei_nfc_cmd {
36	struct mei_nfc_hdr hdr;
37	u8 sub_command;
38	u8 data[];
39} __packed;
40
41struct mei_nfc_reply {
42	struct mei_nfc_hdr hdr;
43	u8 sub_command;
44	u8 reply_status;
45	u8 data[];
46} __packed;
47
48struct mei_nfc_if_version {
49	u8 radio_version_sw[3];
50	u8 reserved[3];
51	u8 radio_version_hw[3];
52	u8 i2c_addr;
53	u8 fw_ivn;
54	u8 vendor_id;
55	u8 radio_type;
56} __packed;
57
58struct mei_nfc_connect {
59	u8 fw_ivn;
60	u8 vendor_id;
61} __packed;
62
63struct mei_nfc_connect_resp {
64	u8 fw_ivn;
65	u8 vendor_id;
66	u16 me_major;
67	u16 me_minor;
68	u16 me_hotfix;
69	u16 me_build;
70} __packed;
71
72
73#define MEI_NFC_CMD_MAINTENANCE 0x00
74#define MEI_NFC_CMD_HCI_SEND 0x01
75#define MEI_NFC_CMD_HCI_RECV 0x02
76
77#define MEI_NFC_SUBCMD_CONNECT    0x00
78#define MEI_NFC_SUBCMD_IF_VERSION 0x01
79
80#define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD)
81
82#define MEI_DUMP_SKB_IN(info, skb)				\
83do {								\
84	pr_debug("%s:\n", info);				\
85	print_hex_dump_debug("mei in : ", DUMP_PREFIX_OFFSET,	\
86			16, 1, (skb)->data, (skb)->len, false);	\
87} while (0)
88
89#define MEI_DUMP_SKB_OUT(info, skb)				\
90do {								\
91	pr_debug("%s:\n", info);				\
92	print_hex_dump_debug("mei out: ", DUMP_PREFIX_OFFSET,	\
93			16, 1, (skb)->data, (skb)->len, false);	\
94} while (0)
95
96#define MEI_DUMP_NFC_HDR(info, _hdr)                                \
97do {                                                                \
98	pr_debug("%s:\n", info);                                    \
99	pr_debug("cmd=%02d status=%d req_id=%d rsvd=%d size=%d\n",  \
100		 (_hdr)->cmd, (_hdr)->status, (_hdr)->req_id,       \
101		 (_hdr)->reserved, (_hdr)->data_size);              \
102} while (0)
103
104static int mei_nfc_if_version(struct nfc_mei_phy *phy)
105{
106
107	struct mei_nfc_cmd cmd;
108	struct mei_nfc_reply *reply = NULL;
109	struct mei_nfc_if_version *version;
110	size_t if_version_length;
111	int bytes_recv, r;
112
113	pr_info("%s\n", __func__);
114
115	memset(&cmd, 0, sizeof(struct mei_nfc_cmd));
116	cmd.hdr.cmd = MEI_NFC_CMD_MAINTENANCE;
117	cmd.hdr.data_size = 1;
118	cmd.sub_command = MEI_NFC_SUBCMD_IF_VERSION;
119
120	MEI_DUMP_NFC_HDR("version", &cmd.hdr);
121	r = mei_cldev_send(phy->cldev, (u8 *)&cmd, sizeof(struct mei_nfc_cmd));
122	if (r < 0) {
123		pr_err("Could not send IF version cmd\n");
124		return r;
125	}
126
127	/* to be sure on the stack we alloc memory */
128	if_version_length = sizeof(struct mei_nfc_reply) +
129		sizeof(struct mei_nfc_if_version);
130
131	reply = kzalloc(if_version_length, GFP_KERNEL);
132	if (!reply)
133		return -ENOMEM;
134
135	bytes_recv = mei_cldev_recv(phy->cldev, (u8 *)reply, if_version_length);
136	if (bytes_recv < 0 || bytes_recv < sizeof(struct mei_nfc_reply)) {
137		pr_err("Could not read IF version\n");
138		r = -EIO;
139		goto err;
140	}
141
142	version = (struct mei_nfc_if_version *)reply->data;
143
144	phy->fw_ivn = version->fw_ivn;
145	phy->vendor_id = version->vendor_id;
146	phy->radio_type = version->radio_type;
147
148err:
149	kfree(reply);
150	return r;
151}
152
153static int mei_nfc_connect(struct nfc_mei_phy *phy)
154{
155	struct mei_nfc_cmd *cmd, *reply;
156	struct mei_nfc_connect *connect;
157	struct mei_nfc_connect_resp *connect_resp;
158	size_t connect_length, connect_resp_length;
159	int bytes_recv, r;
160
161	pr_info("%s\n", __func__);
162
163	connect_length = sizeof(struct mei_nfc_cmd) +
164			sizeof(struct mei_nfc_connect);
165
166	connect_resp_length = sizeof(struct mei_nfc_cmd) +
167			sizeof(struct mei_nfc_connect_resp);
168
169	cmd = kzalloc(connect_length, GFP_KERNEL);
170	if (!cmd)
171		return -ENOMEM;
172	connect = (struct mei_nfc_connect *)cmd->data;
173
174	reply = kzalloc(connect_resp_length, GFP_KERNEL);
175	if (!reply) {
176		kfree(cmd);
177		return -ENOMEM;
178	}
179
180	connect_resp = (struct mei_nfc_connect_resp *)reply->data;
181
182	cmd->hdr.cmd = MEI_NFC_CMD_MAINTENANCE;
183	cmd->hdr.data_size = 3;
184	cmd->sub_command = MEI_NFC_SUBCMD_CONNECT;
185	connect->fw_ivn = phy->fw_ivn;
186	connect->vendor_id = phy->vendor_id;
187
188	MEI_DUMP_NFC_HDR("connect request", &cmd->hdr);
189	r = mei_cldev_send(phy->cldev, (u8 *)cmd, connect_length);
190	if (r < 0) {
191		pr_err("Could not send connect cmd %d\n", r);
192		goto err;
193	}
194
195	bytes_recv = mei_cldev_recv(phy->cldev, (u8 *)reply,
196				    connect_resp_length);
197	if (bytes_recv < 0) {
198		r = bytes_recv;
199		pr_err("Could not read connect response %d\n", r);
200		goto err;
201	}
202
203	MEI_DUMP_NFC_HDR("connect reply", &reply->hdr);
204
205	pr_info("IVN 0x%x Vendor ID 0x%x\n",
206		 connect_resp->fw_ivn, connect_resp->vendor_id);
207
208	pr_info("ME FW %d.%d.%d.%d\n",
209		connect_resp->me_major, connect_resp->me_minor,
210		connect_resp->me_hotfix, connect_resp->me_build);
211
212	r = 0;
213
214err:
215	kfree(reply);
216	kfree(cmd);
217
218	return r;
219}
220
221static int mei_nfc_send(struct nfc_mei_phy *phy, u8 *buf, size_t length)
222{
223	struct mei_nfc_hdr *hdr;
224	u8 *mei_buf;
225	int err;
226
227	err = -ENOMEM;
228	mei_buf = kzalloc(length + MEI_NFC_HEADER_SIZE, GFP_KERNEL);
229	if (!mei_buf)
230		goto out;
231
232	hdr = (struct mei_nfc_hdr *)mei_buf;
233	hdr->cmd = MEI_NFC_CMD_HCI_SEND;
234	hdr->status = 0;
235	hdr->req_id = phy->req_id;
236	hdr->reserved = 0;
237	hdr->data_size = length;
238
239	MEI_DUMP_NFC_HDR("send", hdr);
240
241	memcpy(mei_buf + MEI_NFC_HEADER_SIZE, buf, length);
242	err = mei_cldev_send(phy->cldev, mei_buf, length + MEI_NFC_HEADER_SIZE);
243	if (err < 0)
244		goto out;
245
246	if (!wait_event_interruptible_timeout(phy->send_wq,
247				phy->recv_req_id == phy->req_id, HZ)) {
248		pr_err("NFC MEI command timeout\n");
249		err = -ETIME;
250	} else {
251		phy->req_id++;
252	}
253out:
254	kfree(mei_buf);
255	return err;
256}
257
258/*
259 * Writing a frame must not return the number of written bytes.
260 * It must return either zero for success, or <0 for error.
261 * In addition, it must not alter the skb
262 */
263static int nfc_mei_phy_write(void *phy_id, struct sk_buff *skb)
264{
265	struct nfc_mei_phy *phy = phy_id;
266	int r;
267
268	MEI_DUMP_SKB_OUT("mei frame sent", skb);
269
270	r = mei_nfc_send(phy, skb->data, skb->len);
271	if (r > 0)
272		r = 0;
273
274	return r;
275}
276
277static int mei_nfc_recv(struct nfc_mei_phy *phy, u8 *buf, size_t length)
278{
279	struct mei_nfc_hdr *hdr;
280	int received_length;
281
282	received_length = mei_cldev_recv(phy->cldev, buf, length);
283	if (received_length < 0)
284		return received_length;
285
286	hdr = (struct mei_nfc_hdr *) buf;
287
288	MEI_DUMP_NFC_HDR("receive", hdr);
289	if (hdr->cmd == MEI_NFC_CMD_HCI_SEND) {
290		phy->recv_req_id = hdr->req_id;
291		wake_up(&phy->send_wq);
292
293		return 0;
294	}
295
296	return received_length;
297}
298
299
300static void nfc_mei_event_cb(struct mei_cl_device *cldev, u32 events,
301			     void *context)
302{
303	struct nfc_mei_phy *phy = context;
304
305	if (phy->hard_fault != 0)
306		return;
307
308	if (events & BIT(MEI_CL_EVENT_RX)) {
309		struct sk_buff *skb;
310		int reply_size;
311
312		skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
313		if (!skb)
314			return;
315
316		reply_size = mei_nfc_recv(phy, skb->data, MEI_NFC_MAX_READ);
317		if (reply_size < MEI_NFC_HEADER_SIZE) {
318			kfree_skb(skb);
319			return;
320		}
321
322		skb_put(skb, reply_size);
323		skb_pull(skb, MEI_NFC_HEADER_SIZE);
324
325		MEI_DUMP_SKB_IN("mei frame read", skb);
326
327		nfc_hci_recv_frame(phy->hdev, skb);
328	}
329}
330
331static int nfc_mei_phy_enable(void *phy_id)
332{
333	int r;
334	struct nfc_mei_phy *phy = phy_id;
335
336	pr_info("%s\n", __func__);
337
338	if (phy->powered == 1)
339		return 0;
340
341	r = mei_cldev_enable(phy->cldev);
342	if (r < 0) {
343		pr_err("Could not enable device %d\n", r);
344		return r;
345	}
346
347	r = mei_nfc_if_version(phy);
348	if (r < 0) {
349		pr_err("Could not enable device %d\n", r);
350		goto err;
351	}
352
353	r = mei_nfc_connect(phy);
354	if (r < 0) {
355		pr_err("Could not connect to device %d\n", r);
356		goto err;
357	}
358
359	r = mei_cldev_register_event_cb(phy->cldev, BIT(MEI_CL_EVENT_RX),
360				     nfc_mei_event_cb, phy);
361	if (r) {
362		pr_err("Event cb registration failed %d\n", r);
363		goto err;
364	}
365
366	phy->powered = 1;
367
368	return 0;
369
370err:
371	phy->powered = 0;
372	mei_cldev_disable(phy->cldev);
373	return r;
374}
375
376static void nfc_mei_phy_disable(void *phy_id)
377{
378	struct nfc_mei_phy *phy = phy_id;
379
380	pr_info("%s\n", __func__);
381
382	mei_cldev_disable(phy->cldev);
383
384	phy->powered = 0;
385}
386
387struct nfc_phy_ops mei_phy_ops = {
388	.write = nfc_mei_phy_write,
389	.enable = nfc_mei_phy_enable,
390	.disable = nfc_mei_phy_disable,
391};
392EXPORT_SYMBOL_GPL(mei_phy_ops);
393
394struct nfc_mei_phy *nfc_mei_phy_alloc(struct mei_cl_device *cldev)
395{
396	struct nfc_mei_phy *phy;
397
398	phy = kzalloc(sizeof(struct nfc_mei_phy), GFP_KERNEL);
399	if (!phy)
400		return NULL;
401
402	phy->cldev = cldev;
403	init_waitqueue_head(&phy->send_wq);
404	mei_cldev_set_drvdata(cldev, phy);
405
406	return phy;
407}
408EXPORT_SYMBOL_GPL(nfc_mei_phy_alloc);
409
410void nfc_mei_phy_free(struct nfc_mei_phy *phy)
411{
412	mei_cldev_disable(phy->cldev);
413	kfree(phy);
414}
415EXPORT_SYMBOL_GPL(nfc_mei_phy_free);
416
417MODULE_LICENSE("GPL");
418MODULE_DESCRIPTION("mei bus NFC device interface");
419