1 /* 2 * HCI based Driver for Inside Secure microread NFC Chip 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, write to the 17 * Free Software Foundation, Inc., 18 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 19 */ 20 21 #include <linux/module.h> 22 #include <linux/slab.h> 23 #include <linux/interrupt.h> 24 #include <linux/gpio.h> 25 #include <linux/mei_bus.h> 26 27 #include <linux/nfc.h> 28 #include <net/nfc/hci.h> 29 #include <net/nfc/llc.h> 30 31 #include "microread.h" 32 33 #define MICROREAD_DRIVER_NAME "microread" 34 35 #define MICROREAD_UUID UUID_LE(0x0bb17a78, 0x2a8e, 0x4c50, 0x94, \ 36 0xd4, 0x50, 0x26, 0x67, 0x23, 0x77, 0x5c) 37 38 struct mei_nfc_hdr { 39 u8 cmd; 40 u8 status; 41 u16 req_id; 42 u32 reserved; 43 u16 data_size; 44 } __attribute__((packed)); 45 46 #define MEI_NFC_HEADER_SIZE 10 47 #define MEI_NFC_MAX_HCI_PAYLOAD 300 48 #define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD) 49 50 struct microread_mei_phy { 51 struct mei_device *mei_device; 52 struct nfc_hci_dev *hdev; 53 54 int powered; 55 56 int hard_fault; /* 57 * < 0 if hardware error occured (e.g. i2c err) 58 * and prevents normal operation. 59 */ 60 }; 61 62 #define MEI_DUMP_SKB_IN(info, skb) \ 63 do { \ 64 pr_debug("%s:\n", info); \ 65 print_hex_dump(KERN_DEBUG, "mei in : ", DUMP_PREFIX_OFFSET, \ 66 16, 1, (skb)->data, (skb)->len, 0); \ 67 } while (0) 68 69 #define MEI_DUMP_SKB_OUT(info, skb) \ 70 do { \ 71 pr_debug("%s:\n", info); \ 72 print_hex_dump(KERN_DEBUG, "mei out: ", DUMP_PREFIX_OFFSET, \ 73 16, 1, (skb)->data, (skb)->len, 0); \ 74 } while (0) 75 76 static int microread_mei_enable(void *phy_id) 77 { 78 struct microread_mei_phy *phy = phy_id; 79 80 pr_info(DRIVER_DESC ": %s\n", __func__); 81 82 phy->powered = 1; 83 84 return 0; 85 } 86 87 static void microread_mei_disable(void *phy_id) 88 { 89 struct microread_mei_phy *phy = phy_id; 90 91 pr_info(DRIVER_DESC ": %s\n", __func__); 92 93 phy->powered = 0; 94 } 95 96 /* 97 * Writing a frame must not return the number of written bytes. 98 * It must return either zero for success, or <0 for error. 99 * In addition, it must not alter the skb 100 */ 101 static int microread_mei_write(void *phy_id, struct sk_buff *skb) 102 { 103 struct microread_mei_phy *phy = phy_id; 104 int r; 105 106 MEI_DUMP_SKB_OUT("mei frame sent", skb); 107 108 r = mei_send(phy->device, skb->data, skb->len); 109 if (r > 0) 110 r = 0; 111 112 return r; 113 } 114 115 static void microread_event_cb(struct mei_device *device, u32 events, 116 void *context) 117 { 118 struct microread_mei_phy *phy = context; 119 120 if (phy->hard_fault != 0) 121 return; 122 123 if (events & BIT(MEI_EVENT_RX)) { 124 struct sk_buff *skb; 125 int reply_size; 126 127 skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL); 128 if (!skb) 129 return; 130 131 reply_size = mei_recv(device, skb->data, MEI_NFC_MAX_READ); 132 if (reply_size < MEI_NFC_HEADER_SIZE) { 133 kfree(skb); 134 return; 135 } 136 137 skb_put(skb, reply_size); 138 skb_pull(skb, MEI_NFC_HEADER_SIZE); 139 140 MEI_DUMP_SKB_IN("mei frame read", skb); 141 142 nfc_hci_recv_frame(phy->hdev, skb); 143 } 144 } 145 146 static struct nfc_phy_ops mei_phy_ops = { 147 .write = microread_mei_write, 148 .enable = microread_mei_enable, 149 .disable = microread_mei_disable, 150 }; 151 152 static int microread_mei_probe(struct mei_device *device, 153 const struct mei_id *id) 154 { 155 struct microread_mei_phy *phy; 156 int r; 157 158 pr_info("Probing NFC microread\n"); 159 160 phy = kzalloc(sizeof(struct microread_mei_phy), GFP_KERNEL); 161 if (!phy) { 162 pr_err("Cannot allocate memory for microread mei phy.\n"); 163 return -ENOMEM; 164 } 165 166 phy->device = device; 167 mei_set_clientdata(device, phy); 168 169 r = mei_register_event_cb(device, microread_event_cb, phy); 170 if (r) { 171 pr_err(MICROREAD_DRIVER_NAME ": event cb registration failed\n"); 172 goto err_out; 173 } 174 175 r = microread_probe(phy, &mei_phy_ops, LLC_NOP_NAME, 176 MEI_NFC_HEADER_SIZE, 0, MEI_NFC_MAX_HCI_PAYLOAD, 177 &phy->hdev); 178 if (r < 0) 179 goto err_out; 180 181 return 0; 182 183 err_out: 184 kfree(phy); 185 186 return r; 187 } 188 189 static int microread_mei_remove(struct mei_device *device) 190 { 191 struct microread_mei_phy *phy = mei_get_clientdata(device); 192 193 pr_info("Removing microread\n"); 194 195 microread_remove(phy->hdev); 196 197 if (phy->powered) 198 microread_mei_disable(phy); 199 200 kfree(phy); 201 202 return 0; 203 } 204 205 static struct mei_id microread_mei_tbl[] = { 206 { MICROREAD_DRIVER_NAME, MICROREAD_UUID }, 207 208 /* required last entry */ 209 { } 210 }; 211 212 MODULE_DEVICE_TABLE(mei, microread_mei_tbl); 213 214 static struct mei_driver microread_driver = { 215 .id_table = microread_mei_tbl, 216 .name = MICROREAD_DRIVER_NAME, 217 218 .probe = microread_mei_probe, 219 .remove = microread_mei_remove, 220 }; 221 222 static int microread_mei_init(void) 223 { 224 int r; 225 226 pr_debug(DRIVER_DESC ": %s\n", __func__); 227 228 r = mei_driver_register(µread_driver); 229 if (r) { 230 pr_err(MICROREAD_DRIVER_NAME ": driver registration failed\n"); 231 return r; 232 } 233 234 return 0; 235 } 236 237 static void microread_mei_exit(void) 238 { 239 mei_driver_unregister(µread_driver); 240 } 241 242 module_init(microread_mei_init); 243 module_exit(microread_mei_exit); 244 245 MODULE_LICENSE("GPL"); 246 MODULE_DESCRIPTION(DRIVER_DESC); 247