2013-05-29 07:35:02 -06:00
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/*
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* Copyright (C) 2013 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#define pr_fmt(fmt) "nci_spi: %s: " fmt, __func__
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#include <linux/export.h>
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#include <linux/spi/spi.h>
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2013-05-29 07:35:03 -06:00
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#include <linux/crc-ccitt.h>
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2013-05-29 07:35:02 -06:00
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#include <linux/nfc.h>
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#include <net/nfc/nci_core.h>
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#define NCI_SPI_HDR_LEN 4
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#define NCI_SPI_CRC_LEN 2
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2013-05-29 07:35:04 -06:00
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#define NCI_SPI_ACK_SHIFT 6
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#define NCI_SPI_MSB_PAYLOAD_MASK 0x3F
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2013-05-29 07:35:02 -06:00
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2013-05-29 07:35:03 -06:00
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#define NCI_SPI_SEND_TIMEOUT (NCI_CMD_TIMEOUT > NCI_DATA_TIMEOUT ? \
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NCI_CMD_TIMEOUT : NCI_DATA_TIMEOUT)
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#define NCI_SPI_DIRECT_WRITE 0x01
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#define NCI_SPI_DIRECT_READ 0x02
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#define ACKNOWLEDGE_NONE 0
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#define ACKNOWLEDGE_ACK 1
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#define ACKNOWLEDGE_NACK 2
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#define CRC_INIT 0xFFFF
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2013-05-29 07:35:02 -06:00
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static int nci_spi_open(struct nci_dev *nci_dev)
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{
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struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev);
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return ndev->ops->open(ndev);
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}
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static int nci_spi_close(struct nci_dev *nci_dev)
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{
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struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev);
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return ndev->ops->close(ndev);
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}
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2013-05-29 07:35:03 -06:00
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static int __nci_spi_send(struct nci_spi_dev *ndev, struct sk_buff *skb)
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{
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struct spi_message m;
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struct spi_transfer t;
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t.tx_buf = skb->data;
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t.len = skb->len;
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t.cs_change = 0;
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t.delay_usecs = ndev->xfer_udelay;
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spi_message_init(&m);
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spi_message_add_tail(&t, &m);
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return spi_sync(ndev->spi, &m);
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}
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2013-05-29 07:35:02 -06:00
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static int nci_spi_send(struct nci_dev *nci_dev, struct sk_buff *skb)
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{
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2013-05-29 07:35:03 -06:00
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struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev);
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unsigned int payload_len = skb->len;
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unsigned char *hdr;
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int ret;
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long completion_rc;
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ndev->ops->deassert_int(ndev);
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/* add the NCI SPI header to the start of the buffer */
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hdr = skb_push(skb, NCI_SPI_HDR_LEN);
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hdr[0] = NCI_SPI_DIRECT_WRITE;
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hdr[1] = ndev->acknowledge_mode;
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hdr[2] = payload_len >> 8;
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hdr[3] = payload_len & 0xFF;
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if (ndev->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
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u16 crc;
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crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
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*skb_put(skb, 1) = crc >> 8;
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*skb_put(skb, 1) = crc & 0xFF;
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}
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ret = __nci_spi_send(ndev, skb);
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kfree_skb(skb);
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ndev->ops->assert_int(ndev);
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if (ret != 0 || ndev->acknowledge_mode == NCI_SPI_CRC_DISABLED)
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goto done;
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init_completion(&ndev->req_completion);
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completion_rc =
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wait_for_completion_interruptible_timeout(&ndev->req_completion,
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NCI_SPI_SEND_TIMEOUT);
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if (completion_rc <= 0 || ndev->req_result == ACKNOWLEDGE_NACK)
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ret = -EIO;
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done:
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return ret;
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2013-05-29 07:35:02 -06:00
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}
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static struct nci_ops nci_spi_ops = {
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.open = nci_spi_open,
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.close = nci_spi_close,
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.send = nci_spi_send,
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};
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/* ---- Interface to NCI SPI drivers ---- */
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/**
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* nci_spi_allocate_device - allocate a new nci spi device
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*
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* @spi: SPI device
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* @ops: device operations
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* @supported_protocols: NFC protocols supported by the device
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* @supported_se: NFC Secure Elements supported by the device
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* @acknowledge_mode: Acknowledge mode used by the device
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* @delay: delay between transactions in us
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*/
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struct nci_spi_dev *nci_spi_allocate_device(struct spi_device *spi,
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struct nci_spi_ops *ops,
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u32 supported_protocols,
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u32 supported_se,
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u8 acknowledge_mode,
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unsigned int delay)
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{
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struct nci_spi_dev *ndev;
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int tailroom = 0;
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if (!ops->open || !ops->close || !ops->assert_int || !ops->deassert_int)
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return NULL;
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if (!supported_protocols)
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return NULL;
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2013-09-02 04:34:34 -06:00
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ndev = devm_kzalloc(&spi->dev, sizeof(struct nci_spi_dev), GFP_KERNEL);
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2013-05-29 07:35:02 -06:00
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if (!ndev)
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return NULL;
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ndev->ops = ops;
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ndev->acknowledge_mode = acknowledge_mode;
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ndev->xfer_udelay = delay;
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if (acknowledge_mode == NCI_SPI_CRC_ENABLED)
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tailroom += NCI_SPI_CRC_LEN;
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ndev->nci_dev = nci_allocate_device(&nci_spi_ops, supported_protocols,
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2013-05-07 11:22:11 -06:00
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NCI_SPI_HDR_LEN, tailroom);
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2013-05-29 07:35:02 -06:00
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if (!ndev->nci_dev)
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return NULL;
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nci_set_drvdata(ndev->nci_dev, ndev);
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return ndev;
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}
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EXPORT_SYMBOL_GPL(nci_spi_allocate_device);
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/**
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* nci_spi_free_device - deallocate nci spi device
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*
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* @ndev: The nci spi device to deallocate
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*/
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void nci_spi_free_device(struct nci_spi_dev *ndev)
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{
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nci_free_device(ndev->nci_dev);
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}
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EXPORT_SYMBOL_GPL(nci_spi_free_device);
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/**
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* nci_spi_register_device - register a nci spi device in the nfc subsystem
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*
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* @pdev: The nci spi device to register
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*/
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int nci_spi_register_device(struct nci_spi_dev *ndev)
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{
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return nci_register_device(ndev->nci_dev);
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}
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EXPORT_SYMBOL_GPL(nci_spi_register_device);
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/**
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* nci_spi_unregister_device - unregister a nci spi device in the nfc subsystem
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*
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* @dev: The nci spi device to unregister
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*/
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void nci_spi_unregister_device(struct nci_spi_dev *ndev)
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{
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nci_unregister_device(ndev->nci_dev);
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}
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EXPORT_SYMBOL_GPL(nci_spi_unregister_device);
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2013-05-29 07:35:04 -06:00
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static int send_acknowledge(struct nci_spi_dev *ndev, u8 acknowledge)
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{
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struct sk_buff *skb;
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unsigned char *hdr;
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u16 crc;
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int ret;
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skb = nci_skb_alloc(ndev->nci_dev, 0, GFP_KERNEL);
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/* add the NCI SPI header to the start of the buffer */
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hdr = skb_push(skb, NCI_SPI_HDR_LEN);
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hdr[0] = NCI_SPI_DIRECT_WRITE;
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hdr[1] = NCI_SPI_CRC_ENABLED;
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hdr[2] = acknowledge << NCI_SPI_ACK_SHIFT;
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hdr[3] = 0;
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crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
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*skb_put(skb, 1) = crc >> 8;
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*skb_put(skb, 1) = crc & 0xFF;
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ret = __nci_spi_send(ndev, skb);
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kfree_skb(skb);
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return ret;
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}
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static struct sk_buff *__nci_spi_recv_frame(struct nci_spi_dev *ndev)
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{
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struct sk_buff *skb;
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struct spi_message m;
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unsigned char req[2], resp_hdr[2];
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struct spi_transfer tx, rx;
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unsigned short rx_len = 0;
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int ret;
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spi_message_init(&m);
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req[0] = NCI_SPI_DIRECT_READ;
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req[1] = ndev->acknowledge_mode;
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tx.tx_buf = req;
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tx.len = 2;
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tx.cs_change = 0;
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spi_message_add_tail(&tx, &m);
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rx.rx_buf = resp_hdr;
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rx.len = 2;
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rx.cs_change = 1;
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spi_message_add_tail(&rx, &m);
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ret = spi_sync(ndev->spi, &m);
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if (ret)
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return NULL;
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if (ndev->acknowledge_mode == NCI_SPI_CRC_ENABLED)
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rx_len = ((resp_hdr[0] & NCI_SPI_MSB_PAYLOAD_MASK) << 8) +
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resp_hdr[1] + NCI_SPI_CRC_LEN;
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else
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rx_len = (resp_hdr[0] << 8) | resp_hdr[1];
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skb = nci_skb_alloc(ndev->nci_dev, rx_len, GFP_KERNEL);
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if (!skb)
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return NULL;
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spi_message_init(&m);
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rx.rx_buf = skb_put(skb, rx_len);
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rx.len = rx_len;
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rx.cs_change = 0;
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rx.delay_usecs = ndev->xfer_udelay;
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spi_message_add_tail(&rx, &m);
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ret = spi_sync(ndev->spi, &m);
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if (ret)
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goto receive_error;
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if (ndev->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
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*skb_push(skb, 1) = resp_hdr[1];
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*skb_push(skb, 1) = resp_hdr[0];
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}
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return skb;
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receive_error:
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kfree_skb(skb);
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return NULL;
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}
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static int nci_spi_check_crc(struct sk_buff *skb)
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{
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u16 crc_data = (skb->data[skb->len - 2] << 8) |
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skb->data[skb->len - 1];
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int ret;
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ret = (crc_ccitt(CRC_INIT, skb->data, skb->len - NCI_SPI_CRC_LEN)
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== crc_data);
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skb_trim(skb, skb->len - NCI_SPI_CRC_LEN);
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return ret;
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}
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static u8 nci_spi_get_ack(struct sk_buff *skb)
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{
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u8 ret;
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ret = skb->data[0] >> NCI_SPI_ACK_SHIFT;
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/* Remove NFCC part of the header: ACK, NACK and MSB payload len */
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skb_pull(skb, 2);
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return ret;
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}
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/**
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* nci_spi_recv_frame - receive frame from NCI SPI drivers
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*
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* @ndev: The nci spi device
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* Context: can sleep
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*
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* This call may only be used from a context that may sleep. The sleep
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* is non-interruptible, and has no timeout.
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*
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* It returns zero on success, else a negative error code.
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*/
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int nci_spi_recv_frame(struct nci_spi_dev *ndev)
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{
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struct sk_buff *skb;
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int ret = 0;
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ndev->ops->deassert_int(ndev);
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/* Retrieve frame from SPI */
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skb = __nci_spi_recv_frame(ndev);
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if (!skb) {
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ret = -EIO;
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goto done;
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}
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if (ndev->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
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if (!nci_spi_check_crc(skb)) {
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send_acknowledge(ndev, ACKNOWLEDGE_NACK);
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goto done;
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}
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/* In case of acknowledged mode: if ACK or NACK received,
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* unblock completion of latest frame sent.
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*/
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ndev->req_result = nci_spi_get_ack(skb);
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if (ndev->req_result)
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complete(&ndev->req_completion);
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}
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/* If there is no payload (ACK/NACK only frame),
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* free the socket buffer
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*/
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if (skb->len == 0) {
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kfree_skb(skb);
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|
goto done;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (ndev->acknowledge_mode == NCI_SPI_CRC_ENABLED)
|
|
|
|
send_acknowledge(ndev, ACKNOWLEDGE_ACK);
|
|
|
|
|
|
|
|
/* Forward skb to NCI core layer */
|
|
|
|
ret = nci_recv_frame(ndev->nci_dev, skb);
|
|
|
|
|
|
|
|
done:
|
|
|
|
ndev->ops->assert_int(ndev);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(nci_spi_recv_frame);
|