linux/drivers/nfc/mei_phy.c
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   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#include <linux/module.h>
  22#include <linux/slab.h>
  23#include <linux/nfc.h>
  24
  25#include "mei_phy.h"
  26
  27struct mei_nfc_hdr {
  28        u8 cmd;
  29        u8 status;
  30        u16 req_id;
  31        u32 reserved;
  32        u16 data_size;
  33} __attribute__((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)                              \
  38do {                                                            \
  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)                             \
  45do {                                                            \
  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
  51int 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("MEI_PHY: 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("MEY_PHY: 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}
  80EXPORT_SYMBOL_GPL(nfc_mei_phy_enable);
  81
  82void 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}
  92EXPORT_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 */
  99static 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
 113void 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);
 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}
 142EXPORT_SYMBOL_GPL(nfc_mei_event_cb);
 143
 144struct 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};
 149EXPORT_SYMBOL_GPL(mei_phy_ops);
 150
 151struct 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}
 164EXPORT_SYMBOL_GPL(nfc_mei_phy_alloc);
 165
 166void nfc_mei_phy_free(struct nfc_mei_phy *phy)
 167{
 168        kfree(phy);
 169}
 170EXPORT_SYMBOL_GPL(nfc_mei_phy_free);
 171
 172MODULE_LICENSE("GPL");
 173MODULE_DESCRIPTION("mei bus NFC device interface");
 174
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