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
35#define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD)
36
37#define MEI_DUMP_SKB_IN(info, skb)				\
38do {								\
39	pr_debug("%s:\n", info);				\
40	print_hex_dump_debug("mei in : ", DUMP_PREFIX_OFFSET,	\
41			16, 1, (skb)->data, (skb)->len, false);	\
42} while (0)
43
44#define MEI_DUMP_SKB_OUT(info, skb)				\
45do {								\
46	pr_debug("%s:\n", info);				\
47	print_hex_dump_debug("mei out: ", DUMP_PREFIX_OFFSET,	\
48		       16, 1, (skb)->data, (skb)->len, false);	\
49} while (0)
50
51int nfc_mei_phy_enable(void *phy_id)
52{
53	int r;
54	struct nfc_mei_phy *phy = phy_id;
55
56	pr_info("%s\n", __func__);
57
58	if (phy->powered == 1)
59		return 0;
60
61	r = mei_cl_enable_device(phy->device);
62	if (r < 0) {
63		pr_err("Could not enable device\n");
64		return r;
65	}
66
67	r = mei_cl_register_event_cb(phy->device, nfc_mei_event_cb, phy);
68	if (r) {
69		pr_err("Event cb registration failed\n");
70		mei_cl_disable_device(phy->device);
71		phy->powered = 0;
72
73		return r;
74	}
75
76	phy->powered = 1;
77
78	return 0;
79}
80EXPORT_SYMBOL_GPL(nfc_mei_phy_enable);
81
82void nfc_mei_phy_disable(void *phy_id)
83{
84	struct nfc_mei_phy *phy = phy_id;
85
86	pr_info("%s\n", __func__);
87
88	mei_cl_disable_device(phy->device);
89
90	phy->powered = 0;
91}
92EXPORT_SYMBOL_GPL(nfc_mei_phy_disable);
93
94/*
95 * Writing a frame must not return the number of written bytes.
96 * It must return either zero for success, or <0 for error.
97 * In addition, it must not alter the skb
98 */
99static int nfc_mei_phy_write(void *phy_id, struct sk_buff *skb)
100{
101	struct nfc_mei_phy *phy = phy_id;
102	int r;
103
104	MEI_DUMP_SKB_OUT("mei frame sent", skb);
105
106	r = mei_cl_send(phy->device, skb->data, skb->len);
107	if (r > 0)
108		r = 0;
109
110	return r;
111}
112
113void nfc_mei_event_cb(struct mei_cl_device *device, u32 events, void *context)
114{
115	struct nfc_mei_phy *phy = context;
116
117	if (phy->hard_fault != 0)
118		return;
119
120	if (events & BIT(MEI_CL_EVENT_RX)) {
121		struct sk_buff *skb;
122		int reply_size;
123
124		skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
125		if (!skb)
126			return;
127
128		reply_size = mei_cl_recv(device, skb->data, MEI_NFC_MAX_READ);
129		if (reply_size < MEI_NFC_HEADER_SIZE) {
130			kfree_skb(skb);
131			return;
132		}
133
134		skb_put(skb, reply_size);
135		skb_pull(skb, MEI_NFC_HEADER_SIZE);
136
137		MEI_DUMP_SKB_IN("mei frame read", skb);
138
139		nfc_hci_recv_frame(phy->hdev, skb);
140	}
141}
142EXPORT_SYMBOL_GPL(nfc_mei_event_cb);
143
144struct nfc_phy_ops mei_phy_ops = {
145	.write = nfc_mei_phy_write,
146	.enable = nfc_mei_phy_enable,
147	.disable = nfc_mei_phy_disable,
148};
149EXPORT_SYMBOL_GPL(mei_phy_ops);
150
151struct nfc_mei_phy *nfc_mei_phy_alloc(struct mei_cl_device *device)
152{
153	struct nfc_mei_phy *phy;
154
155	phy = kzalloc(sizeof(struct nfc_mei_phy), GFP_KERNEL);
156	if (!phy)
157		return NULL;
158
159	phy->device = device;
160	mei_cl_set_drvdata(device, phy);
161
162	return phy;
163}
164EXPORT_SYMBOL_GPL(nfc_mei_phy_alloc);
165
166void nfc_mei_phy_free(struct nfc_mei_phy *phy)
167{
168	kfree(phy);
169}
170EXPORT_SYMBOL_GPL(nfc_mei_phy_free);
171
172MODULE_LICENSE("GPL");
173MODULE_DESCRIPTION("mei bus NFC device interface");
174