v4.19.13 snapshot.
diff --git a/net/nfc/nci/spi.c b/net/nfc/nci/spi.c
new file mode 100644
index 0000000..452f4c1
--- /dev/null
+++ b/net/nfc/nci/spi.c
@@ -0,0 +1,331 @@
+/*
+ * 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/module.h>
+
+#include <linux/export.h>
+#include <linux/spi/spi.h>
+#include <linux/crc-ccitt.h>
+#include <net/nfc/nci_core.h>
+
+#define NCI_SPI_ACK_SHIFT 6
+#define NCI_SPI_MSB_PAYLOAD_MASK 0x3F
+
+#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_send(struct nci_spi *nspi, struct sk_buff *skb,
+ int cs_change)
+{
+ struct spi_message m;
+ struct spi_transfer t;
+
+ memset(&t, 0, sizeof(struct spi_transfer));
+ /* a NULL skb means we just want the SPI chip select line to raise */
+ if (skb) {
+ t.tx_buf = skb->data;
+ t.len = skb->len;
+ } else {
+ /* still set tx_buf non NULL to make the driver happy */
+ t.tx_buf = &t;
+ t.len = 0;
+ }
+ t.cs_change = cs_change;
+ t.delay_usecs = nspi->xfer_udelay;
+ t.speed_hz = nspi->xfer_speed_hz;
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t, &m);
+
+ return spi_sync(nspi->spi, &m);
+}
+
+int nci_spi_send(struct nci_spi *nspi,
+ struct completion *write_handshake_completion,
+ struct sk_buff *skb)
+{
+ unsigned int payload_len = skb->len;
+ unsigned char *hdr;
+ int ret;
+ long completion_rc;
+
+ /* 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] = nspi->acknowledge_mode;
+ hdr[2] = payload_len >> 8;
+ hdr[3] = payload_len & 0xFF;
+
+ if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
+ u16 crc;
+
+ crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
+ skb_put_u8(skb, crc >> 8);
+ skb_put_u8(skb, crc & 0xFF);
+ }
+
+ if (write_handshake_completion) {
+ /* Trick SPI driver to raise chip select */
+ ret = __nci_spi_send(nspi, NULL, 1);
+ if (ret)
+ goto done;
+
+ /* wait for NFC chip hardware handshake to complete */
+ if (wait_for_completion_timeout(write_handshake_completion,
+ msecs_to_jiffies(1000)) == 0) {
+ ret = -ETIME;
+ goto done;
+ }
+ }
+
+ ret = __nci_spi_send(nspi, skb, 0);
+ if (ret != 0 || nspi->acknowledge_mode == NCI_SPI_CRC_DISABLED)
+ goto done;
+
+ reinit_completion(&nspi->req_completion);
+ completion_rc = wait_for_completion_interruptible_timeout(
+ &nspi->req_completion,
+ NCI_SPI_SEND_TIMEOUT);
+
+ if (completion_rc <= 0 || nspi->req_result == ACKNOWLEDGE_NACK)
+ ret = -EIO;
+
+done:
+ kfree_skb(skb);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nci_spi_send);
+
+/* ---- Interface to NCI SPI drivers ---- */
+
+/**
+ * nci_spi_allocate_spi - allocate a new nci spi
+ *
+ * @spi: SPI device
+ * @acknowledge_mode: Acknowledge mode used by the NFC device
+ * @delay: delay between transactions in us
+ * @ndev: nci dev to send incoming nci frames to
+ */
+struct nci_spi *nci_spi_allocate_spi(struct spi_device *spi,
+ u8 acknowledge_mode, unsigned int delay,
+ struct nci_dev *ndev)
+{
+ struct nci_spi *nspi;
+
+ nspi = devm_kzalloc(&spi->dev, sizeof(struct nci_spi), GFP_KERNEL);
+ if (!nspi)
+ return NULL;
+
+ nspi->acknowledge_mode = acknowledge_mode;
+ nspi->xfer_udelay = delay;
+ /* Use controller max SPI speed by default */
+ nspi->xfer_speed_hz = 0;
+ nspi->spi = spi;
+ nspi->ndev = ndev;
+ init_completion(&nspi->req_completion);
+
+ return nspi;
+}
+EXPORT_SYMBOL_GPL(nci_spi_allocate_spi);
+
+static int send_acknowledge(struct nci_spi *nspi, u8 acknowledge)
+{
+ struct sk_buff *skb;
+ unsigned char *hdr;
+ u16 crc;
+ int ret;
+
+ skb = nci_skb_alloc(nspi->ndev, 0, GFP_KERNEL);
+
+ /* 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] = NCI_SPI_CRC_ENABLED;
+ hdr[2] = acknowledge << NCI_SPI_ACK_SHIFT;
+ hdr[3] = 0;
+
+ crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
+ skb_put_u8(skb, crc >> 8);
+ skb_put_u8(skb, crc & 0xFF);
+
+ ret = __nci_spi_send(nspi, skb, 0);
+
+ kfree_skb(skb);
+
+ return ret;
+}
+
+static struct sk_buff *__nci_spi_read(struct nci_spi *nspi)
+{
+ struct sk_buff *skb;
+ struct spi_message m;
+ unsigned char req[2], resp_hdr[2];
+ struct spi_transfer tx, rx;
+ unsigned short rx_len = 0;
+ int ret;
+
+ spi_message_init(&m);
+
+ memset(&tx, 0, sizeof(struct spi_transfer));
+ req[0] = NCI_SPI_DIRECT_READ;
+ req[1] = nspi->acknowledge_mode;
+ tx.tx_buf = req;
+ tx.len = 2;
+ tx.cs_change = 0;
+ tx.speed_hz = nspi->xfer_speed_hz;
+ spi_message_add_tail(&tx, &m);
+
+ memset(&rx, 0, sizeof(struct spi_transfer));
+ rx.rx_buf = resp_hdr;
+ rx.len = 2;
+ rx.cs_change = 1;
+ rx.speed_hz = nspi->xfer_speed_hz;
+ spi_message_add_tail(&rx, &m);
+
+ ret = spi_sync(nspi->spi, &m);
+ if (ret)
+ return NULL;
+
+ if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED)
+ rx_len = ((resp_hdr[0] & NCI_SPI_MSB_PAYLOAD_MASK) << 8) +
+ resp_hdr[1] + NCI_SPI_CRC_LEN;
+ else
+ rx_len = (resp_hdr[0] << 8) | resp_hdr[1];
+
+ skb = nci_skb_alloc(nspi->ndev, rx_len, GFP_KERNEL);
+ if (!skb)
+ return NULL;
+
+ spi_message_init(&m);
+
+ memset(&rx, 0, sizeof(struct spi_transfer));
+ rx.rx_buf = skb_put(skb, rx_len);
+ rx.len = rx_len;
+ rx.cs_change = 0;
+ rx.delay_usecs = nspi->xfer_udelay;
+ rx.speed_hz = nspi->xfer_speed_hz;
+ spi_message_add_tail(&rx, &m);
+
+ ret = spi_sync(nspi->spi, &m);
+ if (ret)
+ goto receive_error;
+
+ if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
+ *(u8 *)skb_push(skb, 1) = resp_hdr[1];
+ *(u8 *)skb_push(skb, 1) = resp_hdr[0];
+ }
+
+ return skb;
+
+receive_error:
+ kfree_skb(skb);
+
+ return NULL;
+}
+
+static int nci_spi_check_crc(struct sk_buff *skb)
+{
+ u16 crc_data = (skb->data[skb->len - 2] << 8) |
+ skb->data[skb->len - 1];
+ int ret;
+
+ ret = (crc_ccitt(CRC_INIT, skb->data, skb->len - NCI_SPI_CRC_LEN)
+ == crc_data);
+
+ skb_trim(skb, skb->len - NCI_SPI_CRC_LEN);
+
+ return ret;
+}
+
+static u8 nci_spi_get_ack(struct sk_buff *skb)
+{
+ u8 ret;
+
+ ret = skb->data[0] >> NCI_SPI_ACK_SHIFT;
+
+ /* Remove NFCC part of the header: ACK, NACK and MSB payload len */
+ skb_pull(skb, 2);
+
+ return ret;
+}
+
+/**
+ * nci_spi_read - read frame from NCI SPI drivers
+ *
+ * @nspi: The nci spi
+ * Context: can sleep
+ *
+ * This call may only be used from a context that may sleep. The sleep
+ * is non-interruptible, and has no timeout.
+ *
+ * It returns an allocated skb containing the frame on success, or NULL.
+ */
+struct sk_buff *nci_spi_read(struct nci_spi *nspi)
+{
+ struct sk_buff *skb;
+
+ /* Retrieve frame from SPI */
+ skb = __nci_spi_read(nspi);
+ if (!skb)
+ goto done;
+
+ if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
+ if (!nci_spi_check_crc(skb)) {
+ send_acknowledge(nspi, ACKNOWLEDGE_NACK);
+ goto done;
+ }
+
+ /* In case of acknowledged mode: if ACK or NACK received,
+ * unblock completion of latest frame sent.
+ */
+ nspi->req_result = nci_spi_get_ack(skb);
+ if (nspi->req_result)
+ complete(&nspi->req_completion);
+ }
+
+ /* If there is no payload (ACK/NACK only frame),
+ * free the socket buffer
+ */
+ if (!skb->len) {
+ kfree_skb(skb);
+ skb = NULL;
+ goto done;
+ }
+
+ if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED)
+ send_acknowledge(nspi, ACKNOWLEDGE_ACK);
+
+done:
+
+ return skb;
+}
+EXPORT_SYMBOL_GPL(nci_spi_read);
+
+MODULE_LICENSE("GPL");