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, write to the
  17  * Free Software Foundation, Inc.,
  18  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/module.h>
  24 #include <linux/slab.h>
  25 #include <linux/nfc.h>
  26
  27 #include "mei_phy.h"
  28
  29 struct mei_nfc_hdr {
  30         u8 cmd;
  31         u8 status;
  32         u16 req_id;
  33         u32 reserved;
  34         u16 data_size;
  35 } __packed;
  36
  37 #define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD)
  38
  39 #define MEI_DUMP_SKB_IN(info, skb)                              \
  40 do {                                                            \
  41         pr_debug("%s:\n", info);                                \
  42         print_hex_dump_debug("mei in : ", DUMP_PREFIX_OFFSET,   \
  43                         16, 1, (skb)->data, (skb)->len, false); \
  44 } while (0)
  45
  46 #define MEI_DUMP_SKB_OUT(info, skb)                             \
  47 do {                                                            \
  48         pr_debug("%s:\n", info);                                \
  49         print_hex_dump_debug("mei out: ", DUMP_PREFIX_OFFSET,   \
  50                        16, 1, (skb)->data, (skb)->len, false);  \
  51 } while (0)
  52
  53 int nfc_mei_phy_enable(void *phy_id)
  54 {
  55         int r;
  56         struct nfc_mei_phy *phy = phy_id;
  57
  58         pr_info("%s\n", __func__);
  59
  60         if (phy->powered == 1)
  61                 return 0;
  62
  63         r = mei_cl_enable_device(phy->device);
  64         if (r < 0) {
  65                 pr_err("Could not enable device\n");
  66                 return r;
  67         }
  68
  69         r = mei_cl_register_event_cb(phy->device, nfc_mei_event_cb, phy);
  70         if (r) {
  71                 pr_err("Event cb registration failed\n");
  72                 mei_cl_disable_device(phy->device);
  73                 phy->powered = 0;
  74
  75                 return r;
  76         }
  77
  78         phy->powered = 1;
  79
  80         return 0;
  81 }
  82 EXPORT_SYMBOL_GPL(nfc_mei_phy_enable);
  83
  84 void nfc_mei_phy_disable(void *phy_id)
  85 {
  86         struct nfc_mei_phy *phy = phy_id;
  87
  88         pr_info("%s\n", __func__);
  89
  90         mei_cl_disable_device(phy->device);
  91
  92         phy->powered = 0;
  93 }
  94 EXPORT_SYMBOL_GPL(nfc_mei_phy_disable);
  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 nfc_mei_phy_write(void *phy_id, struct sk_buff *skb)
 102 {
 103         struct nfc_mei_phy *phy = phy_id;
 104         int r;
 105
 106         MEI_DUMP_SKB_OUT("mei frame sent", skb);
 107
 108         r = mei_cl_send(phy->device, skb->data, skb->len);
 109         if (r > 0)
 110                 r = 0;
 111
 112         return r;
 113 }
 114
 115 void nfc_mei_event_cb(struct mei_cl_device *device, u32 events, void *context)
 116 {
 117         struct nfc_mei_phy *phy = context;
 118
 119         if (phy->hard_fault != 0)
 120                 return;
 121
 122         if (events & BIT(MEI_CL_EVENT_RX)) {
 123                 struct sk_buff *skb;
 124                 int reply_size;
 125
 126                 skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
 127                 if (!skb)
 128                         return;
 129
 130                 reply_size = mei_cl_recv(device, skb->data, MEI_NFC_MAX_READ);
 131                 if (reply_size < MEI_NFC_HEADER_SIZE) {
 132                         kfree(skb);
 133                         return;
 134                 }
 135
 136                 skb_put(skb, reply_size);
 137                 skb_pull(skb, MEI_NFC_HEADER_SIZE);
 138
 139                 MEI_DUMP_SKB_IN("mei frame read", skb);
 140
 141                 nfc_hci_recv_frame(phy->hdev, skb);
 142         }
 143 }
 144 EXPORT_SYMBOL_GPL(nfc_mei_event_cb);
 145
 146 struct nfc_phy_ops mei_phy_ops = {
 147         .write = nfc_mei_phy_write,
 148         .enable = nfc_mei_phy_enable,
 149         .disable = nfc_mei_phy_disable,
 150 };
 151 EXPORT_SYMBOL_GPL(mei_phy_ops);
 152
 153 struct nfc_mei_phy *nfc_mei_phy_alloc(struct mei_cl_device *device)
 154 {
 155         struct nfc_mei_phy *phy;
 156
 157         phy = kzalloc(sizeof(struct nfc_mei_phy), GFP_KERNEL);
 158         if (!phy)
 159                 return NULL;
 160
 161         phy->device = device;
 162         mei_cl_set_drvdata(device, phy);
 163
 164         return phy;
 165 }
 166 EXPORT_SYMBOL_GPL(nfc_mei_phy_alloc);
 167
 168 void nfc_mei_phy_free(struct nfc_mei_phy *phy)
 169 {
 170         kfree(phy);
 171 }
 172 EXPORT_SYMBOL_GPL(nfc_mei_phy_free);
 173
 174 MODULE_LICENSE("GPL");
 175 MODULE_DESCRIPTION("mei bus NFC device interface");