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/*
* HCI based Driver for Inside Secure microread NFC Chip
*
* Copyright (C) 2013 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/mei_bus.h>
#include <linux/nfc.h>
#include <net/nfc/hci.h>
#include <net/nfc/llc.h>
#include "microread.h"
#define MICROREAD_DRIVER_NAME "microread"
#define MICROREAD_UUID UUID_LE(0x0bb17a78, 0x2a8e, 0x4c50, 0x94, \
0xd4, 0x50, 0x26, 0x67, 0x23, 0x77, 0x5c)
struct mei_nfc_hdr {
u8 cmd;
u8 status;
u16 req_id;
u32 reserved;
u16 data_size;
} __attribute__((packed));
#define MEI_NFC_HEADER_SIZE 10
#define MEI_NFC_MAX_HCI_PAYLOAD 300
#define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD)
struct microread_mei_phy {
struct mei_device *mei_device;
struct nfc_hci_dev *hdev;
int powered;
int hard_fault; /*
* < 0 if hardware error occured (e.g. i2c err)
* and prevents normal operation.
*/
};
#define MEI_DUMP_SKB_IN(info, skb) \
do { \
pr_debug("%s:\n", info); \
print_hex_dump(KERN_DEBUG, "mei in : ", DUMP_PREFIX_OFFSET, \
16, 1, (skb)->data, (skb)->len, 0); \
} while (0)
#define MEI_DUMP_SKB_OUT(info, skb) \
do { \
pr_debug("%s:\n", info); \
print_hex_dump(KERN_DEBUG, "mei out: ", DUMP_PREFIX_OFFSET, \
16, 1, (skb)->data, (skb)->len, 0); \
} while (0)
static int microread_mei_enable(void *phy_id)
{
struct microread_mei_phy *phy = phy_id;
pr_info(DRIVER_DESC ": %s\n", __func__);
phy->powered = 1;
return 0;
}
static void microread_mei_disable(void *phy_id)
{
struct microread_mei_phy *phy = phy_id;
pr_info(DRIVER_DESC ": %s\n", __func__);
phy->powered = 0;
}
/*
* Writing a frame must not return the number of written bytes.
* It must return either zero for success, or <0 for error.
* In addition, it must not alter the skb
*/
static int microread_mei_write(void *phy_id, struct sk_buff *skb)
{
struct microread_mei_phy *phy = phy_id;
int r;
MEI_DUMP_SKB_OUT("mei frame sent", skb);
r = mei_send(phy->device, skb->data, skb->len);
if (r > 0)
r = 0;
return r;
}
static void microread_event_cb(struct mei_device *device, u32 events,
void *context)
{
struct microread_mei_phy *phy = context;
if (phy->hard_fault != 0)
return;
if (events & BIT(MEI_EVENT_RX)) {
struct sk_buff *skb;
int reply_size;
skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
if (!skb)
return;
reply_size = mei_recv(device, skb->data, MEI_NFC_MAX_READ);
if (reply_size < MEI_NFC_HEADER_SIZE) {
kfree(skb);
return;
}
skb_put(skb, reply_size);
skb_pull(skb, MEI_NFC_HEADER_SIZE);
MEI_DUMP_SKB_IN("mei frame read", skb);
nfc_hci_recv_frame(phy->hdev, skb);
}
}
static struct nfc_phy_ops mei_phy_ops = {
.write = microread_mei_write,
.enable = microread_mei_enable,
.disable = microread_mei_disable,
};
static int microread_mei_probe(struct mei_device *device,
const struct mei_id *id)
{
struct microread_mei_phy *phy;
int r;
pr_info("Probing NFC microread\n");
phy = kzalloc(sizeof(struct microread_mei_phy), GFP_KERNEL);
if (!phy) {
pr_err("Cannot allocate memory for microread mei phy.\n");
return -ENOMEM;
}
phy->device = device;
mei_set_clientdata(device, phy);
r = mei_register_event_cb(device, microread_event_cb, phy);
if (r) {
pr_err(MICROREAD_DRIVER_NAME ": event cb registration failed\n");
goto err_out;
}
r = microread_probe(phy, &mei_phy_ops, LLC_NOP_NAME,
MEI_NFC_HEADER_SIZE, 0, MEI_NFC_MAX_HCI_PAYLOAD,
&phy->hdev);
if (r < 0)
goto err_out;
return 0;
err_out:
kfree(phy);
return r;
}
static int microread_mei_remove(struct mei_device *device)
{
struct microread_mei_phy *phy = mei_get_clientdata(device);
pr_info("Removing microread\n");
microread_remove(phy->hdev);
if (phy->powered)
microread_mei_disable(phy);
kfree(phy);
return 0;
}
static struct mei_id microread_mei_tbl[] = {
{ MICROREAD_DRIVER_NAME, MICROREAD_UUID },
/* required last entry */
{ }
};
MODULE_DEVICE_TABLE(mei, microread_mei_tbl);
static struct mei_driver microread_driver = {
.id_table = microread_mei_tbl,
.name = MICROREAD_DRIVER_NAME,
.probe = microread_mei_probe,
.remove = microread_mei_remove,
};
static int microread_mei_init(void)
{
int r;
pr_debug(DRIVER_DESC ": %s\n", __func__);
r = mei_driver_register(µread_driver);
if (r) {
pr_err(MICROREAD_DRIVER_NAME ": driver registration failed\n");
return r;
}
return 0;
}
static void microread_mei_exit(void)
{
mei_driver_unregister(µread_driver);
}
module_init(microread_mei_init);
module_exit(microread_mei_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(DRIVER_DESC);
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