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_cl_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 struct mei_nfc_hdr { 36 u8 cmd; 37 u8 status; 38 u16 req_id; 39 u32 reserved; 40 u16 data_size; 41 } __attribute__((packed)); 42 43 #define MEI_NFC_HEADER_SIZE 10 44 #define MEI_NFC_MAX_HCI_PAYLOAD 300 45 #define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD) 46 47 struct microread_mei_phy { 48 struct mei_cl_device *device; 49 struct nfc_hci_dev *hdev; 50 51 int powered; 52 53 int hard_fault; /* 54 * < 0 if hardware error occured (e.g. i2c err) 55 * and prevents normal operation. 56 */ 57 }; 58 59 #define MEI_DUMP_SKB_IN(info, skb) \ 60 do { \ 61 pr_debug("%s:\n", info); \ 62 print_hex_dump(KERN_DEBUG, "mei in : ", DUMP_PREFIX_OFFSET, \ 63 16, 1, (skb)->data, (skb)->len, 0); \ 64 } while (0) 65 66 #define MEI_DUMP_SKB_OUT(info, skb) \ 67 do { \ 68 pr_debug("%s:\n", info); \ 69 print_hex_dump(KERN_DEBUG, "mei out: ", DUMP_PREFIX_OFFSET, \ 70 16, 1, (skb)->data, (skb)->len, 0); \ 71 } while (0) 72 73 static int microread_mei_enable(void *phy_id) 74 { 75 struct microread_mei_phy *phy = phy_id; 76 77 pr_info(DRIVER_DESC ": %s\n", __func__); 78 79 phy->powered = 1; 80 81 return 0; 82 } 83 84 static void microread_mei_disable(void *phy_id) 85 { 86 struct microread_mei_phy *phy = phy_id; 87 88 pr_info(DRIVER_DESC ": %s\n", __func__); 89 90 phy->powered = 0; 91 } 92 93 /* 94 * Writing a frame must not return the number of written bytes. 95 * It must return either zero for success, or <0 for error. 96 * In addition, it must not alter the skb 97 */ 98 static int microread_mei_write(void *phy_id, struct sk_buff *skb) 99 { 100 struct microread_mei_phy *phy = phy_id; 101 int r; 102 103 MEI_DUMP_SKB_OUT("mei frame sent", skb); 104 105 r = mei_cl_send(phy->device, skb->data, skb->len); 106 if (r > 0) 107 r = 0; 108 109 return r; 110 } 111 112 static void microread_event_cb(struct mei_cl_device *device, u32 events, 113 void *context) 114 { 115 struct microread_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); 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 } 142 143 static struct nfc_phy_ops mei_phy_ops = { 144 .write = microread_mei_write, 145 .enable = microread_mei_enable, 146 .disable = microread_mei_disable, 147 }; 148 149 static int microread_mei_probe(struct mei_cl_device *device, 150 const struct mei_cl_device_id *id) 151 { 152 struct microread_mei_phy *phy; 153 int r; 154 155 pr_info("Probing NFC microread\n"); 156 157 phy = kzalloc(sizeof(struct microread_mei_phy), GFP_KERNEL); 158 if (!phy) { 159 pr_err("Cannot allocate memory for microread mei phy.\n"); 160 return -ENOMEM; 161 } 162 163 phy->device = device; 164 mei_cl_set_drvdata(device, phy); 165 166 r = mei_cl_register_event_cb(device, microread_event_cb, phy); 167 if (r) { 168 pr_err(MICROREAD_DRIVER_NAME ": event cb registration failed\n"); 169 goto err_out; 170 } 171 172 r = microread_probe(phy, &mei_phy_ops, LLC_NOP_NAME, 173 MEI_NFC_HEADER_SIZE, 0, MEI_NFC_MAX_HCI_PAYLOAD, 174 &phy->hdev); 175 if (r < 0) 176 goto err_out; 177 178 return 0; 179 180 err_out: 181 kfree(phy); 182 183 return r; 184 } 185 186 static int microread_mei_remove(struct mei_cl_device *device) 187 { 188 struct microread_mei_phy *phy = mei_cl_get_drvdata(device); 189 190 pr_info("Removing microread\n"); 191 192 microread_remove(phy->hdev); 193 194 if (phy->powered) 195 microread_mei_disable(phy); 196 197 kfree(phy); 198 199 return 0; 200 } 201 202 static struct mei_cl_device_id microread_mei_tbl[] = { 203 { MICROREAD_DRIVER_NAME }, 204 205 /* required last entry */ 206 { } 207 }; 208 MODULE_DEVICE_TABLE(mei, microread_mei_tbl); 209 210 static struct mei_cl_driver microread_driver = { 211 .id_table = microread_mei_tbl, 212 .name = MICROREAD_DRIVER_NAME, 213 214 .probe = microread_mei_probe, 215 .remove = microread_mei_remove, 216 }; 217 218 static int microread_mei_init(void) 219 { 220 int r; 221 222 pr_debug(DRIVER_DESC ": %s\n", __func__); 223 224 r = mei_cl_driver_register(µread_driver); 225 if (r) { 226 pr_err(MICROREAD_DRIVER_NAME ": driver registration failed\n"); 227 return r; 228 } 229 230 return 0; 231 } 232 233 static void microread_mei_exit(void) 234 { 235 mei_cl_driver_unregister(µread_driver); 236 } 237 238 module_init(microread_mei_init); 239 module_exit(microread_mei_exit); 240 241 MODULE_LICENSE("GPL"); 242 MODULE_DESCRIPTION(DRIVER_DESC); 243