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Commit ee9596d4 authored by Frederic Danis's avatar Frederic Danis Committed by Samuel Ortiz
Browse files

NFC: Add NCI over SPI send 



Before any operation, driver interruption is de-asserted to prevent
race condition between TX and RX.

The NCI over SPI header is added in front of NCI packet.
If acknowledged mode is set, CRC-16-CCITT is added to the packet.
Then the packet is forwarded to SPI module to be sent.

A delay after the transaction is added.
This delay is determined by the driver during nci_spi_allocate_device()
call and can be 0.

After data has been sent, driver interruption is re-asserted.

If acknowledged mode is set, nci_spi_send will block until
acknowledgment is received.

Signed-off-by: default avatarFrederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
parent 8a00a61b

include/net/nfc/nci_core.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -226,6 +226,9 @@ struct nci_spi_dev { 
						  transactions */

						  transactions */

	u8			acknowledge_mode;

	u8			acknowledge_mode;





	struct completion	req_completion;

	u8			req_result;



	void			*driver_data;

	void			*driver_data;

};

};

net/nfc/nci/spi.c

+70 −1
Original line number Original line Diff line number Diff line
@@ -20,12 +20,25 @@ 




#include <linux/export.h>

#include <linux/export.h>

#include <linux/spi/spi.h>

#include <linux/spi/spi.h>

#include <linux/crc-ccitt.h>

#include <linux/nfc.h>

#include <linux/nfc.h>

#include <net/nfc/nci_core.h>

#include <net/nfc/nci_core.h>





#define NCI_SPI_HDR_LEN			4

#define NCI_SPI_HDR_LEN			4

#define NCI_SPI_CRC_LEN			2

#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)

static int nci_spi_open(struct nci_dev *nci_dev)

{

{

	struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev);

	struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev);
@@ -40,9 +53,65 @@ static int nci_spi_close(struct nci_dev *nci_dev) 
	return ndev->ops->close(ndev);

	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)

static int nci_spi_send(struct nci_dev *nci_dev, struct sk_buff *skb)

{

{

	return 0;

	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 = {

static struct nci_ops nci_spi_ops = {