drivers/nfc/mei_phy.c

   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
  27 struct 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)                              \
  38 do {                                                            \
  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)                             \
  45 do {                                                            \
  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
  51 int 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 }
  80 EXPORT_SYMBOL_GPL(nfc_mei_phy_enable);
  81
  82 void 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 }
  92 EXPORT_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  */
  99 static 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
 113 void 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 }
 142 EXPORT_SYMBOL_GPL(nfc_mei_event_cb);
 143
 144 struct 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 };
 149 EXPORT_SYMBOL_GPL(mei_phy_ops);
 150
 151 struct 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 }
 164 EXPORT_SYMBOL_GPL(nfc_mei_phy_alloc);
 165
 166 void nfc_mei_phy_free(struct nfc_mei_phy *phy)
 167 {
 168         kfree(phy);
 169 }
 170 EXPORT_SYMBOL_GPL(nfc_mei_phy_free);
 171
 172 MODULE_LICENSE("GPL");
 173 MODULE_DESCRIPTION("mei bus NFC device interface");