NFC: NCI: Simplify NCI SPI to become a simple framing/checking layer

NCI SPI layer should not manage the nci dev, this is the job of the nci
chipset driver. This layer should be limited to frame/deframe nci
packets, and optionnaly check integrity (crc) and manage the ack/nak
protocol.

The NCI SPI must not be mixed up with an NCI dev. spi_[dev|device] are
therefore renamed to a simple spi for more clarity.
The header and crc sizes are moved to nci.h so that drivers can use
them to reserve space in outgoing skbs.
nci_spi_send() is exported to be accessible by drivers.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 55 insertions, 125 deletions

diff --git a/net/nfc/nci/spi.c b/net/nfc/nci/spi.c
index e66fda4d9ede..910dfd8015f4 100644
--- a/net/nfc/nci/spi.c
+++ b/net/nfc/nci/spi.c
@@ -24,8 +24,6 @@
 #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_ACK_SHIFT               6
 #define NCI_SPI_MSB_PAYLOAD_MASK        0x3F
 
@@ -41,21 +39,7 @@
 
 #define CRC_INIT                0xFFFF
 
-static int nci_spi_open(struct nci_dev *ndev)
-{
-        struct nci_spi_dev *nsdev = nci_get_drvdata(ndev);
-
-        return nsdev->ops->open(nsdev);
-}
-
-static int nci_spi_close(struct nci_dev *ndev)
-{
-        struct nci_spi_dev *nsdev = nci_get_drvdata(ndev);
-
-        return nsdev->ops->close(nsdev);
-}
-
-static int __nci_spi_send(struct nci_spi_dev *nsdev, struct sk_buff *skb)
+static int __nci_spi_send(struct nci_spi *nspi, struct sk_buff *skb)
 {
         struct spi_message m;
         struct spi_transfer t;
@@ -63,32 +47,31 @@ static int __nci_spi_send(struct nci_spi_dev *nsdev, struct sk_buff *skb)
         t.tx_buf = skb->data;
         t.len = skb->len;
         t.cs_change = 0;
-        t.delay_usecs = nsdev->xfer_udelay;
+        t.delay_usecs = nspi->xfer_udelay;
 
         spi_message_init(&m);
         spi_message_add_tail(&t, &m);
 
-        return spi_sync(nsdev->spi, &m);
+        return spi_sync(nspi->spi, &m);
 }
 
-static int nci_spi_send(struct nci_dev *ndev, struct sk_buff *skb)
+int nci_spi_send(struct nci_spi *nspi, struct sk_buff *skb)
 {
-        struct nci_spi_dev *nsdev = nci_get_drvdata(ndev);
         unsigned int payload_len = skb->len;
         unsigned char *hdr;
         int ret;
         long completion_rc;
 
-        nsdev->ops->deassert_int(nsdev);
+        nspi->ops->deassert_int(nspi);
 
         /* 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] = nsdev->acknowledge_mode;
+        hdr[1] = nspi->acknowledge_mode;
         hdr[2] = payload_len >> 8;
         hdr[3] = payload_len & 0xFF;
 
-        if (nsdev->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
+        if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
                 u16 crc;
 
                 crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
@@ -96,123 +79,70 @@ static int nci_spi_send(struct nci_dev *ndev, struct sk_buff *skb)
                 *skb_put(skb, 1) = crc & 0xFF;
         }
 
-        ret = __nci_spi_send(nsdev, skb);
+        ret = __nci_spi_send(nspi, skb);
 
         kfree_skb(skb);
-        nsdev->ops->assert_int(nsdev);
+        nspi->ops->assert_int(nspi);
 
-        if (ret != 0 || nsdev->acknowledge_mode == NCI_SPI_CRC_DISABLED)
+        if (ret != 0 || nspi->acknowledge_mode == NCI_SPI_CRC_DISABLED)
                 goto done;
 
-        init_completion(&nsdev->req_completion);
+        init_completion(&nspi->req_completion);
         completion_rc = wait_for_completion_interruptible_timeout(
-                                                        &nsdev->req_completion,
+                                                        &nspi->req_completion,
                                                         NCI_SPI_SEND_TIMEOUT);
 
-        if (completion_rc <= 0 || nsdev->req_result == ACKNOWLEDGE_NACK)
+        if (completion_rc <= 0 || nspi->req_result == ACKNOWLEDGE_NACK)
                 ret = -EIO;
 
 done:
         return ret;
 }
-
-static struct nci_ops nci_spi_ops = {
-        .open = nci_spi_open,
-        .close = nci_spi_close,
-        .send = nci_spi_send,
-};
+EXPORT_SYMBOL_GPL(nci_spi_send);
 
 /* ---- Interface to NCI SPI drivers ---- */
 
 /**
- * nci_spi_allocate_device - allocate a new nci spi device
+ * nci_spi_allocate_spi - allocate a new nci spi
  *
  * @spi: SPI device
  * @ops: device operations
- * @supported_protocols: NFC protocols supported by the device
- * @supported_se: NFC Secure Elements supported by the device
- * @acknowledge_mode: Acknowledge mode used by the 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_dev *nci_spi_allocate_device(struct spi_device *spi,
-                                                struct nci_spi_ops *ops,
-                                                u32 supported_protocols,
-                                                u32 supported_se,
-                                                u8 acknowledge_mode,
-                                                unsigned int delay)
+struct nci_spi *nci_spi_allocate_spi(struct spi_device *spi,
+                                     struct nci_spi_ops *ops,
+                                     u8 acknowledge_mode, unsigned int delay,
+                                     struct nci_dev *ndev)
 {
-        struct nci_spi_dev *nsdev;
-        int tailroom = 0;
-
-        if (!ops->open || !ops->close || !ops->assert_int || !ops->deassert_int)
-                return NULL;
-
-        if (!supported_protocols)
-                return NULL;
+        struct nci_spi *nspi;
 
-        nsdev = devm_kzalloc(&spi->dev, sizeof(struct nci_spi_dev), GFP_KERNEL);
-        if (!nsdev)
+        if (!ops->assert_int || !ops->deassert_int)
                 return NULL;
 
-        nsdev->ops = ops;
-        nsdev->acknowledge_mode = acknowledge_mode;
-        nsdev->xfer_udelay = delay;
-
-        if (acknowledge_mode == NCI_SPI_CRC_ENABLED)
-                tailroom += NCI_SPI_CRC_LEN;
-
-        nsdev->ndev = nci_allocate_device(&nci_spi_ops, supported_protocols,
-                                          NCI_SPI_HDR_LEN, tailroom);
-        if (!nsdev->ndev)
+        nspi = devm_kzalloc(&spi->dev, sizeof(struct nci_spi), GFP_KERNEL);
+        if (!nspi)
                 return NULL;
 
-        nci_set_drvdata(nsdev->ndev, nsdev);
-
-        return nsdev;
-}
-EXPORT_SYMBOL_GPL(nci_spi_allocate_device);
-
-/**
- * nci_spi_free_device - deallocate nci spi device
- *
- * @nsdev: The nci spi device to deallocate
- */
-void nci_spi_free_device(struct nci_spi_dev *nsdev)
-{
-        nci_free_device(nsdev->ndev);
-}
-EXPORT_SYMBOL_GPL(nci_spi_free_device);
+        nspi->ops = ops;
+        nspi->acknowledge_mode = acknowledge_mode;
+        nspi->xfer_udelay = delay;
 
-/**
- * nci_spi_register_device - register a nci spi device in the nfc subsystem
- *
- * @pdev: The nci spi device to register
- */
-int nci_spi_register_device(struct nci_spi_dev *nsdev)
-{
-        return nci_register_device(nsdev->ndev);
-}
-EXPORT_SYMBOL_GPL(nci_spi_register_device);
+        nspi->ndev = ndev;
 
-/**
- * nci_spi_unregister_device - unregister a nci spi device in the nfc subsystem
- *
- * @dev: The nci spi device to unregister
- */
-void nci_spi_unregister_device(struct nci_spi_dev *nsdev)
-{
-        nci_unregister_device(nsdev->ndev);
+        return nspi;
 }
-EXPORT_SYMBOL_GPL(nci_spi_unregister_device);
+EXPORT_SYMBOL_GPL(nci_spi_allocate_spi);
 
-static int send_acknowledge(struct nci_spi_dev *nsdev, u8 acknowledge)
+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(nsdev->ndev, 0, GFP_KERNEL);
+        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);
@@ -225,14 +155,14 @@ static int send_acknowledge(struct nci_spi_dev *nsdev, u8 acknowledge)
         *skb_put(skb, 1) = crc >> 8;
         *skb_put(skb, 1) = crc & 0xFF;
 
-        ret = __nci_spi_send(nsdev, skb);
+        ret = __nci_spi_send(nspi, skb);
 
         kfree_skb(skb);
 
         return ret;
 }
 
-static struct sk_buff *__nci_spi_recv_frame(struct nci_spi_dev *nsdev)
+static struct sk_buff *__nci_spi_recv_frame(struct nci_spi *nspi)
 {
         struct sk_buff *skb;
         struct spi_message m;
@@ -243,7 +173,7 @@ static struct sk_buff *__nci_spi_recv_frame(struct nci_spi_dev *nsdev)
 
         spi_message_init(&m);
         req[0] = NCI_SPI_DIRECT_READ;
-        req[1] = nsdev->acknowledge_mode;
+        req[1] = nspi->acknowledge_mode;
         tx.tx_buf = req;
         tx.len = 2;
         tx.cs_change = 0;
@@ -252,18 +182,18 @@ static struct sk_buff *__nci_spi_recv_frame(struct nci_spi_dev *nsdev)
         rx.len = 2;
         rx.cs_change = 1;
         spi_message_add_tail(&rx, &m);
-        ret = spi_sync(nsdev->spi, &m);
+        ret = spi_sync(nspi->spi, &m);
 
         if (ret)
                 return NULL;
 
-        if (nsdev->acknowledge_mode == NCI_SPI_CRC_ENABLED)
+        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(nsdev->ndev, rx_len, GFP_KERNEL);
+        skb = nci_skb_alloc(nspi->ndev, rx_len, GFP_KERNEL);
         if (!skb)
                 return NULL;
 
@@ -271,14 +201,14 @@ static struct sk_buff *__nci_spi_recv_frame(struct nci_spi_dev *nsdev)
         rx.rx_buf = skb_put(skb, rx_len);
         rx.len = rx_len;
         rx.cs_change = 0;
-        rx.delay_usecs = nsdev->xfer_udelay;
+        rx.delay_usecs = nspi->xfer_udelay;
         spi_message_add_tail(&rx, &m);
-        ret = spi_sync(nsdev->spi, &m);
+        ret = spi_sync(nspi->spi, &m);
 
         if (ret)
                 goto receive_error;
 
-        if (nsdev->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
+        if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
                 *skb_push(skb, 1) = resp_hdr[1];
                 *skb_push(skb, 1) = resp_hdr[0];
         }
@@ -320,7 +250,7 @@ static u8 nci_spi_get_ack(struct sk_buff *skb)
 /**
  * nci_spi_recv_frame - receive frame from NCI SPI drivers
  *
- * @nsdev: The nci spi device
+ * @nspi: The nci spi
  * Context: can sleep
  *
  * This call may only be used from a context that may sleep.  The sleep
@@ -328,32 +258,32 @@ static u8 nci_spi_get_ack(struct sk_buff *skb)
  *
  * It returns zero on success, else a negative error code.
  */
-int nci_spi_recv_frame(struct nci_spi_dev *nsdev)
+int nci_spi_recv_frame(struct nci_spi *nspi)
 {
         struct sk_buff *skb;
         int ret = 0;
 
-        nsdev->ops->deassert_int(nsdev);
+        nspi->ops->deassert_int(nspi);
 
         /* Retrieve frame from SPI */
-        skb = __nci_spi_recv_frame(nsdev);
+        skb = __nci_spi_recv_frame(nspi);
         if (!skb) {
                 ret = -EIO;
                 goto done;
         }
 
-        if (nsdev->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
+        if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
                 if (!nci_spi_check_crc(skb)) {
-                        send_acknowledge(nsdev, ACKNOWLEDGE_NACK);
+                        send_acknowledge(nspi, ACKNOWLEDGE_NACK);
                         goto done;
                 }
 
                 /* In case of acknowledged mode: if ACK or NACK received,
                  * unblock completion of latest frame sent.
                  */
-                nsdev->req_result = nci_spi_get_ack(skb);
-                if (nsdev->req_result)
-                        complete(&nsdev->req_completion);
+                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),
@@ -364,14 +294,14 @@ int nci_spi_recv_frame(struct nci_spi_dev *nsdev)
                 goto done;
         }
 
-        if (nsdev->acknowledge_mode == NCI_SPI_CRC_ENABLED)
-                send_acknowledge(nsdev, ACKNOWLEDGE_ACK);
+        if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED)
+                send_acknowledge(nspi, ACKNOWLEDGE_ACK);
 
         /* Forward skb to NCI core layer */
-        ret = nci_recv_frame(nsdev->ndev, skb);
+        ret = nci_recv_frame(nspi->ndev, skb);
 
 done:
-        nsdev->ops->assert_int(nsdev);
+        nspi->ops->assert_int(nspi);
 
         return ret;
 }