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/*
* 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 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.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#define pr_fmt(fmt) "nci_spi: %s: " fmt, __func__
#include <linux/export.h>
#include <linux/spi/spi.h>
#include <linux/crc-ccitt.h>
#include <linux/nfc.h>
#include <net/nfc/nci_core.h>
#define NCI_SPI_HDR_LEN 4
#define NCI_SPI_CRC_LEN 2
#define NCI_SPI_SEND_TIMEOUT (NCI_CMD_TIMEOUT > NCI_DATA_TIMEOUT ? \
NCI_CMD_TIMEOUT : NCI_DATA_TIMEOUT)
#define NCI_SPI_DIRECT_WRITE 0x01
#define NCI_SPI_DIRECT_READ 0x02
#define ACKNOWLEDGE_NONE 0
#define ACKNOWLEDGE_ACK 1
#define ACKNOWLEDGE_NACK 2
#define CRC_INIT 0xFFFF
static int nci_spi_open(struct nci_dev *nci_dev)
{
struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev);
return ndev->ops->open(ndev);
}
static int nci_spi_close(struct nci_dev *nci_dev)
{
struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev);
return ndev->ops->close(ndev);
}
static int __nci_spi_send(struct nci_spi_dev *ndev, struct sk_buff *skb)
{
struct spi_message m;
struct spi_transfer t;
t.tx_buf = skb->data;
t.len = skb->len;
t.cs_change = 0;
t.delay_usecs = ndev->xfer_udelay;
spi_message_init(&m);
spi_message_add_tail(&t, &m);
return spi_sync(ndev->spi, &m);
}
static int nci_spi_send(struct nci_dev *nci_dev, struct sk_buff *skb)
{
struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev);
unsigned int payload_len = skb->len;
unsigned char *hdr;
int ret;
long completion_rc;
ndev->ops->deassert_int(ndev);
/* add the NCI SPI header to the start of the buffer */
hdr = skb_push(skb, NCI_SPI_HDR_LEN);
hdr[0] = NCI_SPI_DIRECT_WRITE;
hdr[1] = ndev->acknowledge_mode;
hdr[2] = payload_len >> 8;
hdr[3] = payload_len & 0xFF;
if (ndev->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
u16 crc;
crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
*skb_put(skb, 1) = crc >> 8;
*skb_put(skb, 1) = crc & 0xFF;
}
ret = __nci_spi_send(ndev, skb);
kfree_skb(skb);
ndev->ops->assert_int(ndev);
if (ret != 0 || ndev->acknowledge_mode == NCI_SPI_CRC_DISABLED)
goto done;
init_completion(&ndev->req_completion);
completion_rc =
wait_for_completion_interruptible_timeout(&ndev->req_completion,
NCI_SPI_SEND_TIMEOUT);
if (completion_rc <= 0 || ndev->req_result == ACKNOWLEDGE_NACK)
ret = -EIO;
done:
return ret;
}
static struct nci_ops nci_spi_ops = {
.open = nci_spi_open,
.close = nci_spi_close,
.send = nci_spi_send,
};
/* ---- Interface to NCI SPI drivers ---- */
/**
* nci_spi_allocate_device - allocate a new nci spi device
*
* @spi: SPI device
* @ops: device operations
* @supported_protocols: NFC protocols supported by the device
* @supported_se: NFC Secure Elements supported by the device
* @acknowledge_mode: Acknowledge mode used by the device
* @delay: delay between transactions in us
*/
struct nci_spi_dev *nci_spi_allocate_device(struct spi_device *spi,
struct nci_spi_ops *ops,
u32 supported_protocols,
u32 supported_se,
u8 acknowledge_mode,
unsigned int delay)
{
struct nci_spi_dev *ndev;
int tailroom = 0;
if (!ops->open || !ops->close || !ops->assert_int || !ops->deassert_int)
return NULL;
if (!supported_protocols)
return NULL;
ndev = devm_kzalloc(&spi->dev, sizeof(struct nci_dev), GFP_KERNEL);
if (!ndev)
return NULL;
ndev->ops = ops;
ndev->acknowledge_mode = acknowledge_mode;
ndev->xfer_udelay = delay;
if (acknowledge_mode == NCI_SPI_CRC_ENABLED)
tailroom += NCI_SPI_CRC_LEN;
ndev->nci_dev = nci_allocate_device(&nci_spi_ops, supported_protocols,
supported_se, NCI_SPI_HDR_LEN,
tailroom);
if (!ndev->nci_dev)
return NULL;
nci_set_drvdata(ndev->nci_dev, ndev);
return ndev;
}
EXPORT_SYMBOL_GPL(nci_spi_allocate_device);
/**
* nci_spi_free_device - deallocate nci spi device
*
* @ndev: The nci spi device to deallocate
*/
void nci_spi_free_device(struct nci_spi_dev *ndev)
{
nci_free_device(ndev->nci_dev);
}
EXPORT_SYMBOL_GPL(nci_spi_free_device);
/**
* nci_spi_register_device - register a nci spi device in the nfc subsystem
*
* @pdev: The nci spi device to register
*/
int nci_spi_register_device(struct nci_spi_dev *ndev)
{
return nci_register_device(ndev->nci_dev);
}
EXPORT_SYMBOL_GPL(nci_spi_register_device);
/**
* nci_spi_unregister_device - unregister a nci spi device in the nfc subsystem
*
* @dev: The nci spi device to unregister
*/
void nci_spi_unregister_device(struct nci_spi_dev *ndev)
{
nci_unregister_device(ndev->nci_dev);
}
EXPORT_SYMBOL_GPL(nci_spi_unregister_device);
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