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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: Frederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This commit is contained in:
Frederic Danis 2013-05-29 15:35:03 +02:00 committed by Samuel Ortiz
parent 8a00a61b0e
commit ee9596d467
2 changed files with 73 additions and 1 deletions
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3
include/net/nfc/nci_core.h
View File

@ -226,6 +226,9 @@ struct nci_spi_dev {
transactions */
u8 acknowledge_mode;
struct completion req_completion;
u8 req_result;
void *driver_data;
};

71
net/nfc/nci/spi.c
View File

@ -20,12 +20,25 @@
#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);
@ -40,9 +53,65 @@ static int nci_spi_close(struct nci_dev *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)
{
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 = {