1 files changed, 156 insertions, 0 deletions

diff --git a/drivers/net/ethernet/qualcomm/qca_framing.c b/drivers/net/ethernet/qualcomm/qca_framing.c
new file mode 100644
index 000000000000..faa924c85e29
--- /dev/null
+++ b/drivers/net/ethernet/qualcomm/qca_framing.c
@@ -0,0 +1,156 @@
+/*
+ *   Copyright (c) 2011, 2012, Atheros Communications Inc.
+ *   Copyright (c) 2014, I2SE GmbH
+ *
+ *   Permission to use, copy, modify, and/or distribute this software
+ *   for any purpose with or without fee is hereby granted, provided
+ *   that the above copyright notice and this permission notice appear
+ *   in all copies.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+ *   WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+ *   WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
+ *   THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+ *   CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ *   LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ *   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ *   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*   Atheros ethernet framing. Every Ethernet frame is surrounded
+ *   by an atheros frame while transmitted over a serial channel;
+ */
+
+#include <linux/kernel.h>
+
+#include "qca_framing.h"
+
+u16
+qcafrm_create_header(u8 *buf, u16 length)
+{
+        __le16 len;
+
+        if (!buf)
+                return 0;
+
+        len = cpu_to_le16(length);
+
+        buf[0] = 0xAA;
+        buf[1] = 0xAA;
+        buf[2] = 0xAA;
+        buf[3] = 0xAA;
+        buf[4] = len & 0xff;
+        buf[5] = (len >> 8) & 0xff;
+        buf[6] = 0;
+        buf[7] = 0;
+
+        return QCAFRM_HEADER_LEN;
+}
+
+u16
+qcafrm_create_footer(u8 *buf)
+{
+        if (!buf)
+                return 0;
+
+        buf[0] = 0x55;
+        buf[1] = 0x55;
+        return QCAFRM_FOOTER_LEN;
+}
+
+/*   Gather received bytes and try to extract a full ethernet frame by
+ *   following a simple state machine.
+ *
+ * Return:   QCAFRM_GATHER       No ethernet frame fully received yet.
+ *           QCAFRM_NOHEAD       Header expected but not found.
+ *           QCAFRM_INVLEN       Atheros frame length is invalid
+ *           QCAFRM_NOTAIL       Footer expected but not found.
+ *           > 0                 Number of byte in the fully received
+ *                               Ethernet frame
+ */
+
+s32
+qcafrm_fsm_decode(struct qcafrm_handle *handle, u8 *buf, u16 buf_len, u8 recv_byte)
+{
+        s32 ret = QCAFRM_GATHER;
+        u16 len;
+
+        switch (handle->state) {
+        case QCAFRM_HW_LEN0:
+        case QCAFRM_HW_LEN1:
+                /* by default, just go to next state */
+                handle->state--;
+
+                if (recv_byte != 0x00) {
+                        /* first two bytes of length must be 0 */
+                        handle->state = QCAFRM_HW_LEN0;
+                }
+                break;
+        case QCAFRM_HW_LEN2:
+        case QCAFRM_HW_LEN3:
+                handle->state--;
+                break;
+        /* 4 bytes header pattern */
+        case QCAFRM_WAIT_AA1:
+        case QCAFRM_WAIT_AA2:
+        case QCAFRM_WAIT_AA3:
+        case QCAFRM_WAIT_AA4:
+                if (recv_byte != 0xAA) {
+                        ret = QCAFRM_NOHEAD;
+                        handle->state = QCAFRM_HW_LEN0;
+                } else {
+                        handle->state--;
+                }
+                break;
+                /* 2 bytes length. */
+                /* Borrow offset field to hold length for now. */
+        case QCAFRM_WAIT_LEN_BYTE0:
+                handle->offset = recv_byte;
+                handle->state = QCAFRM_WAIT_LEN_BYTE1;
+                break;
+        case QCAFRM_WAIT_LEN_BYTE1:
+                handle->offset = handle->offset | (recv_byte << 8);
+                handle->state = QCAFRM_WAIT_RSVD_BYTE1;
+                break;
+        case QCAFRM_WAIT_RSVD_BYTE1:
+                handle->state = QCAFRM_WAIT_RSVD_BYTE2;
+                break;
+        case QCAFRM_WAIT_RSVD_BYTE2:
+                len = handle->offset;
+                if (len > buf_len || len < QCAFRM_ETHMINLEN) {
+                        ret = QCAFRM_INVLEN;
+                        handle->state = QCAFRM_HW_LEN0;
+                } else {
+                        handle->state = (enum qcafrm_state)(len + 1);
+                        /* Remaining number of bytes. */
+                        handle->offset = 0;
+                }
+                break;
+        default:
+                /* Receiving Ethernet frame itself. */
+                buf[handle->offset] = recv_byte;
+                handle->offset++;
+                handle->state--;
+                break;
+        case QCAFRM_WAIT_551:
+                if (recv_byte != 0x55) {
+                        ret = QCAFRM_NOTAIL;
+                        handle->state = QCAFRM_HW_LEN0;
+                } else {
+                        handle->state = QCAFRM_WAIT_552;
+                }
+                break;
+        case QCAFRM_WAIT_552:
+                if (recv_byte != 0x55) {
+                        ret = QCAFRM_NOTAIL;
+                        handle->state = QCAFRM_HW_LEN0;
+                } else {
+                        ret = handle->offset;
+                        /* Frame is fully received. */
+                        handle->state = QCAFRM_HW_LEN0;
+                }
+                break;
+        }
+
+        return ret;
+}