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8a00a61b FD |
1 | /* |
2 | * Copyright (C) 2013 Intel Corporation. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms and conditions of the GNU General Public License, | |
6 | * version 2, as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along with | |
14 | * this program; if not, write to the Free Software Foundation, Inc., | |
15 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | |
16 | * | |
17 | */ | |
18 | ||
19 | #define pr_fmt(fmt) "nci_spi: %s: " fmt, __func__ | |
20 | ||
21 | #include <linux/export.h> | |
22 | #include <linux/spi/spi.h> | |
ee9596d4 | 23 | #include <linux/crc-ccitt.h> |
8a00a61b FD |
24 | #include <linux/nfc.h> |
25 | #include <net/nfc/nci_core.h> | |
26 | ||
27 | #define NCI_SPI_HDR_LEN 4 | |
28 | #define NCI_SPI_CRC_LEN 2 | |
29 | ||
ee9596d4 FD |
30 | #define NCI_SPI_SEND_TIMEOUT (NCI_CMD_TIMEOUT > NCI_DATA_TIMEOUT ? \ |
31 | NCI_CMD_TIMEOUT : NCI_DATA_TIMEOUT) | |
32 | ||
33 | #define NCI_SPI_DIRECT_WRITE 0x01 | |
34 | #define NCI_SPI_DIRECT_READ 0x02 | |
35 | ||
36 | #define ACKNOWLEDGE_NONE 0 | |
37 | #define ACKNOWLEDGE_ACK 1 | |
38 | #define ACKNOWLEDGE_NACK 2 | |
39 | ||
40 | #define CRC_INIT 0xFFFF | |
41 | ||
8a00a61b FD |
42 | static int nci_spi_open(struct nci_dev *nci_dev) |
43 | { | |
44 | struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev); | |
45 | ||
46 | return ndev->ops->open(ndev); | |
47 | } | |
48 | ||
49 | static int nci_spi_close(struct nci_dev *nci_dev) | |
50 | { | |
51 | struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev); | |
52 | ||
53 | return ndev->ops->close(ndev); | |
54 | } | |
55 | ||
ee9596d4 FD |
56 | static int __nci_spi_send(struct nci_spi_dev *ndev, struct sk_buff *skb) |
57 | { | |
58 | struct spi_message m; | |
59 | struct spi_transfer t; | |
60 | ||
61 | t.tx_buf = skb->data; | |
62 | t.len = skb->len; | |
63 | t.cs_change = 0; | |
64 | t.delay_usecs = ndev->xfer_udelay; | |
65 | ||
66 | spi_message_init(&m); | |
67 | spi_message_add_tail(&t, &m); | |
68 | ||
69 | return spi_sync(ndev->spi, &m); | |
70 | } | |
71 | ||
8a00a61b FD |
72 | static int nci_spi_send(struct nci_dev *nci_dev, struct sk_buff *skb) |
73 | { | |
ee9596d4 FD |
74 | struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev); |
75 | unsigned int payload_len = skb->len; | |
76 | unsigned char *hdr; | |
77 | int ret; | |
78 | long completion_rc; | |
79 | ||
80 | ndev->ops->deassert_int(ndev); | |
81 | ||
82 | /* add the NCI SPI header to the start of the buffer */ | |
83 | hdr = skb_push(skb, NCI_SPI_HDR_LEN); | |
84 | hdr[0] = NCI_SPI_DIRECT_WRITE; | |
85 | hdr[1] = ndev->acknowledge_mode; | |
86 | hdr[2] = payload_len >> 8; | |
87 | hdr[3] = payload_len & 0xFF; | |
88 | ||
89 | if (ndev->acknowledge_mode == NCI_SPI_CRC_ENABLED) { | |
90 | u16 crc; | |
91 | ||
92 | crc = crc_ccitt(CRC_INIT, skb->data, skb->len); | |
93 | *skb_put(skb, 1) = crc >> 8; | |
94 | *skb_put(skb, 1) = crc & 0xFF; | |
95 | } | |
96 | ||
97 | ret = __nci_spi_send(ndev, skb); | |
98 | ||
99 | kfree_skb(skb); | |
100 | ndev->ops->assert_int(ndev); | |
101 | ||
102 | if (ret != 0 || ndev->acknowledge_mode == NCI_SPI_CRC_DISABLED) | |
103 | goto done; | |
104 | ||
105 | init_completion(&ndev->req_completion); | |
106 | completion_rc = | |
107 | wait_for_completion_interruptible_timeout(&ndev->req_completion, | |
108 | NCI_SPI_SEND_TIMEOUT); | |
109 | ||
110 | if (completion_rc <= 0 || ndev->req_result == ACKNOWLEDGE_NACK) | |
111 | ret = -EIO; | |
112 | ||
113 | done: | |
114 | return ret; | |
8a00a61b FD |
115 | } |
116 | ||
117 | static struct nci_ops nci_spi_ops = { | |
118 | .open = nci_spi_open, | |
119 | .close = nci_spi_close, | |
120 | .send = nci_spi_send, | |
121 | }; | |
122 | ||
123 | /* ---- Interface to NCI SPI drivers ---- */ | |
124 | ||
125 | /** | |
126 | * nci_spi_allocate_device - allocate a new nci spi device | |
127 | * | |
128 | * @spi: SPI device | |
129 | * @ops: device operations | |
130 | * @supported_protocols: NFC protocols supported by the device | |
131 | * @supported_se: NFC Secure Elements supported by the device | |
132 | * @acknowledge_mode: Acknowledge mode used by the device | |
133 | * @delay: delay between transactions in us | |
134 | */ | |
135 | struct nci_spi_dev *nci_spi_allocate_device(struct spi_device *spi, | |
136 | struct nci_spi_ops *ops, | |
137 | u32 supported_protocols, | |
138 | u32 supported_se, | |
139 | u8 acknowledge_mode, | |
140 | unsigned int delay) | |
141 | { | |
142 | struct nci_spi_dev *ndev; | |
143 | int tailroom = 0; | |
144 | ||
145 | if (!ops->open || !ops->close || !ops->assert_int || !ops->deassert_int) | |
146 | return NULL; | |
147 | ||
148 | if (!supported_protocols) | |
149 | return NULL; | |
150 | ||
151 | ndev = devm_kzalloc(&spi->dev, sizeof(struct nci_dev), GFP_KERNEL); | |
152 | if (!ndev) | |
153 | return NULL; | |
154 | ||
155 | ndev->ops = ops; | |
156 | ndev->acknowledge_mode = acknowledge_mode; | |
157 | ndev->xfer_udelay = delay; | |
158 | ||
159 | if (acknowledge_mode == NCI_SPI_CRC_ENABLED) | |
160 | tailroom += NCI_SPI_CRC_LEN; | |
161 | ||
162 | ndev->nci_dev = nci_allocate_device(&nci_spi_ops, supported_protocols, | |
163 | supported_se, NCI_SPI_HDR_LEN, | |
164 | tailroom); | |
165 | if (!ndev->nci_dev) | |
166 | return NULL; | |
167 | ||
168 | nci_set_drvdata(ndev->nci_dev, ndev); | |
169 | ||
170 | return ndev; | |
171 | } | |
172 | EXPORT_SYMBOL_GPL(nci_spi_allocate_device); | |
173 | ||
174 | /** | |
175 | * nci_spi_free_device - deallocate nci spi device | |
176 | * | |
177 | * @ndev: The nci spi device to deallocate | |
178 | */ | |
179 | void nci_spi_free_device(struct nci_spi_dev *ndev) | |
180 | { | |
181 | nci_free_device(ndev->nci_dev); | |
182 | } | |
183 | EXPORT_SYMBOL_GPL(nci_spi_free_device); | |
184 | ||
185 | /** | |
186 | * nci_spi_register_device - register a nci spi device in the nfc subsystem | |
187 | * | |
188 | * @pdev: The nci spi device to register | |
189 | */ | |
190 | int nci_spi_register_device(struct nci_spi_dev *ndev) | |
191 | { | |
192 | return nci_register_device(ndev->nci_dev); | |
193 | } | |
194 | EXPORT_SYMBOL_GPL(nci_spi_register_device); | |
195 | ||
196 | /** | |
197 | * nci_spi_unregister_device - unregister a nci spi device in the nfc subsystem | |
198 | * | |
199 | * @dev: The nci spi device to unregister | |
200 | */ | |
201 | void nci_spi_unregister_device(struct nci_spi_dev *ndev) | |
202 | { | |
203 | nci_unregister_device(ndev->nci_dev); | |
204 | } | |
205 | EXPORT_SYMBOL_GPL(nci_spi_unregister_device); |