bluetooth: hci_bcsp.c small cleanups/api users

Use bitrev16 from lib/bitrev.c.

Use the get_unaligned_be16 to get the crc from the packet, create a
small helper function for this.

Fix a shadowed variable sparse warning:
drivers/bluetooth/hci_bcsp.c:218:26: warning: symbol 'hdr' shadows an earlier one
drivers/bluetooth/hci_bcsp.c:187:5: originally declared here

[akpm@linux-foundation.org: select CONFIG_BITREVERSE, noted by akinobu.mita@gmail.com]
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 14 insertions, 31 deletions

diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
index 075598e1c502..71a58a4e1795 100644
--- a/drivers/bluetooth/Kconfig
+++ b/drivers/bluetooth/Kconfig
@@ -71,6 +71,7 @@ config BT_HCIUART_H4
 config BT_HCIUART_BCSP
         bool "BCSP protocol support"
         depends on BT_HCIUART
+        select CONFIG_BITREVERSE
         help
           BCSP (BlueCore Serial Protocol) is serial protocol for communication 
           between Bluetooth device and host. This protocol is required for non
diff --git a/drivers/bluetooth/hci_bcsp.c b/drivers/bluetooth/hci_bcsp.c
index 696f7528f022..4d37bb312ee3 100644
--- a/drivers/bluetooth/hci_bcsp.c
+++ b/drivers/bluetooth/hci_bcsp.c
@@ -39,6 +39,8 @@
 #include <linux/signal.h>
 #include <linux/ioctl.h>
 #include <linux/skbuff.h>
+#include <linux/bitrev.h>
+#include <asm/unaligned.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -124,27 +126,6 @@ static void bcsp_crc_update(u16 *crc, u8 d)
         *crc = reg;
 }
 
-/*
-   Get reverse of generated crc
-
-   Implementation note
-        The crc generator (bcsp_crc_init() and bcsp_crc_update())
-        creates a reversed crc, so it needs to be swapped back before
-        being passed on.
-*/
-static u16 bcsp_crc_reverse(u16 crc)
-{
-        u16 b, rev;
-
-        for (b = 0, rev = 0; b < 16; b++) {
-                rev = rev << 1;
-                rev |= (crc & 1);
-                crc = crc >> 1;
-        }
-
-        return (rev);
-}
-
 /* ---- BCSP core ---- */
 
 static void bcsp_slip_msgdelim(struct sk_buff *skb)
@@ -235,10 +216,10 @@ static struct sk_buff *bcsp_prepare_pkt(struct bcsp_struct *bcsp, u8 *data,
         }
 
         if (hciextn && chan == 5) {
-                struct hci_command_hdr *hdr = (struct hci_command_hdr *) data;
+                __le16 opcode = ((struct hci_command_hdr *)data)->opcode;
 
                 /* Vendor specific commands */
-                if (hci_opcode_ogf(__le16_to_cpu(hdr->opcode)) == 0x3f) {
+                if (hci_opcode_ogf(__le16_to_cpu(opcode)) == 0x3f) {
                         u8 desc = *(data + HCI_COMMAND_HDR_SIZE);
                         if ((desc & 0xf0) == 0xc0) {
                                 data += HCI_COMMAND_HDR_SIZE + 1;
@@ -296,7 +277,7 @@ static struct sk_buff *bcsp_prepare_pkt(struct bcsp_struct *bcsp, u8 *data,
 
         /* Put CRC */
         if (bcsp->use_crc) {
-                bcsp_txmsg_crc = bcsp_crc_reverse(bcsp_txmsg_crc);
+                bcsp_txmsg_crc = bitrev16(bcsp_txmsg_crc);
                 bcsp_slip_one_byte(nskb, (u8) ((bcsp_txmsg_crc >> 8) & 0x00ff));
                 bcsp_slip_one_byte(nskb, (u8) (bcsp_txmsg_crc & 0x00ff));
         }
@@ -566,6 +547,11 @@ static void bcsp_complete_rx_pkt(struct hci_uart *hu)
         bcsp->rx_skb = NULL;
 }
 
+static u16 bscp_get_crc(struct bcsp_struct *bcsp)
+{
+        return get_unaligned_be16(&bcsp->rx_skb->data[bcsp->rx_skb->len - 2]);
+}
+
 /* Recv data */
 static int bcsp_recv(struct hci_uart *hu, void *data, int count)
 {
@@ -624,14 +610,10 @@ static int bcsp_recv(struct hci_uart *hu, void *data, int count)
                         continue;
 
                 case BCSP_W4_CRC:
-                        if (bcsp_crc_reverse(bcsp->message_crc) !=
-                                        (bcsp->rx_skb->data[bcsp->rx_skb->len - 2] << 8) +
-                                        bcsp->rx_skb->data[bcsp->rx_skb->len - 1]) {
-
+                        if (bitrev16(bcsp->message_crc) != bscp_get_crc(bcsp)) {
                                 BT_ERR ("Checksum failed: computed %04x received %04x",
-                                        bcsp_crc_reverse(bcsp->message_crc),
-                                        (bcsp->rx_skb-> data[bcsp->rx_skb->len - 2] << 8) +
-                                        bcsp->rx_skb->data[bcsp->rx_skb->len - 1]);
+                                        bitrev16(bcsp->message_crc),
+                                        bscp_get_crc(bcsp));
 
                                 kfree_skb(bcsp->rx_skb);
                                 bcsp->rx_state = BCSP_W4_PKT_DELIMITER;