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path: root/drivers/net/ethernet/qualcomm/qca_framing.c
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Diffstat (limited to 'drivers/net/ethernet/qualcomm/qca_framing.c')
-rw-r--r--drivers/net/ethernet/qualcomm/qca_framing.c156
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;
+}