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| author | Frederic Danis <frederic.danis@linux.intel.com> | 2013-05-29 15:35:03 +0200 |
|---|---|---|
| committer | Samuel Ortiz <sameo@linux.intel.com> | 2013-06-14 13:44:15 +0200 |
| commit | ee9596d467e4d05c77a8c883aeeb5b74d1a3cd31 (patch) | |
| tree | 256dad6d872ced15c55723fcdccfcdcf3d87734a /net/nfc | |
| parent | 8a00a61b0ef2bfd1b468dd20c0d0b1a94a8f7475 (diff) | |
| download | linux-ee9596d467e4d05c77a8c883aeeb5b74d1a3cd31.tar.gz | |
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>
Diffstat (limited to 'net/nfc')
| -rw-r--r-- | net/nfc/nci/spi.c | 71 |
1 files changed, 70 insertions, 1 deletions
diff --git a/net/nfc/nci/spi.c b/net/nfc/nci/spi.c index ebcdba51418c..6258461e6998 100644 --- a/net/nfc/nci/spi.c +++ b/net/nfc/nci/spi.c @@ -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 = { |