drivers/net/ethernet/qualcomm/qca_framing.h

   1 /*
   2  *   Copyright (c) 2011, 2012, Atheros Communications Inc.
   3  *   Copyright (c) 2014, I2SE GmbH
   4  *
   5  *   Permission to use, copy, modify, and/or distribute this software
   6  *   for any purpose with or without fee is hereby granted, provided
   7  *   that the above copyright notice and this permission notice appear
   8  *   in all copies.
   9  *
  10  *   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
  11  *   WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
  12  *   WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
  13  *   THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
  14  *   CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  15  *   LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  16  *   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  17  *   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 /*   Atheros Ethernet framing. Every Ethernet frame is surrounded by an atheros
  21  *   frame while transmitted over a serial channel.
  22  */
  23
  24 #ifndef _QCA_FRAMING_H
  25 #define _QCA_FRAMING_H
  26
  27 #include <linux/if_ether.h>
  28 #include <linux/if_vlan.h>
  29 #include <linux/types.h>
  30
  31 /* Frame is currently being received */
  32 #define QCAFRM_GATHER 0
  33
  34 /*  No header byte while expecting it */
  35 #define QCAFRM_NOHEAD (QCAFRM_ERR_BASE - 1)
  36
  37 /* No tailer byte while expecting it */
  38 #define QCAFRM_NOTAIL (QCAFRM_ERR_BASE - 2)
  39
  40 /* Frame length is invalid */
  41 #define QCAFRM_INVLEN (QCAFRM_ERR_BASE - 3)
  42
  43 /* Frame length is invalid */
  44 #define QCAFRM_INVFRAME (QCAFRM_ERR_BASE - 4)
  45
  46 /* Min/Max Ethernet MTU */
  47 #define QCAFRM_ETHMINMTU 46
  48 #define QCAFRM_ETHMAXMTU 1500
  49
  50 /* Min/Max frame lengths */
  51 #define QCAFRM_ETHMINLEN (QCAFRM_ETHMINMTU + ETH_HLEN)
  52 #define QCAFRM_ETHMAXLEN (QCAFRM_ETHMAXMTU + VLAN_ETH_HLEN)
  53
  54 /* QCA7K header len */
  55 #define QCAFRM_HEADER_LEN 8
  56
  57 /* QCA7K footer len */
  58 #define QCAFRM_FOOTER_LEN 2
  59
  60 /* QCA7K Framing. */
  61 #define QCAFRM_ERR_BASE -1000
  62
  63 enum qcafrm_state {
  64         QCAFRM_HW_LEN0 = 0x8000,
  65         QCAFRM_HW_LEN1 = QCAFRM_HW_LEN0 - 1,
  66         QCAFRM_HW_LEN2 = QCAFRM_HW_LEN1 - 1,
  67         QCAFRM_HW_LEN3 = QCAFRM_HW_LEN2 - 1,
  68
  69         /*  Waiting first 0xAA of header */
  70         QCAFRM_WAIT_AA1 = QCAFRM_HW_LEN3 - 1,
  71
  72         /*  Waiting second 0xAA of header */
  73         QCAFRM_WAIT_AA2 = QCAFRM_WAIT_AA1 - 1,
  74
  75         /*  Waiting third 0xAA of header */
  76         QCAFRM_WAIT_AA3 = QCAFRM_WAIT_AA2 - 1,
  77
  78         /*  Waiting fourth 0xAA of header */
  79         QCAFRM_WAIT_AA4 = QCAFRM_WAIT_AA3 - 1,
  80
  81         /*  Waiting Byte 0-1 of length (litte endian) */
  82         QCAFRM_WAIT_LEN_BYTE0 = QCAFRM_WAIT_AA4 - 1,
  83         QCAFRM_WAIT_LEN_BYTE1 = QCAFRM_WAIT_AA4 - 2,
  84
  85         /* Reserved bytes */
  86         QCAFRM_WAIT_RSVD_BYTE1 = QCAFRM_WAIT_AA4 - 3,
  87         QCAFRM_WAIT_RSVD_BYTE2 = QCAFRM_WAIT_AA4 - 4,
  88
  89         /*  The frame length is used as the state until
  90          *  the end of the Ethernet frame
  91          *  Waiting for first 0x55 of footer
  92          */
  93         QCAFRM_WAIT_551 = 1,
  94
  95         /*  Waiting for second 0x55 of footer */
  96         QCAFRM_WAIT_552 = QCAFRM_WAIT_551 - 1
  97 };
  98
  99 /*   Structure to maintain the frame decoding during reception. */
 100
 101 struct qcafrm_handle {
 102         /*  Current decoding state */
 103         enum qcafrm_state state;
 104
 105         /* Offset in buffer (borrowed for length too) */
 106         s16 offset;
 107
 108         /* Frame length as kept by this module */
 109         u16 len;
 110 };
 111
 112 u16 qcafrm_create_header(u8 *buf, u16 len);
 113
 114 u16 qcafrm_create_footer(u8 *buf);
 115
 116 static inline void qcafrm_fsm_init(struct qcafrm_handle *handle)
 117 {
 118         handle->state = QCAFRM_HW_LEN0;
 119 }
 120
 121 /*   Gather received bytes and try to extract a full Ethernet frame
 122  *   by following a simple state machine.
 123  *
 124  * Return:   QCAFRM_GATHER       No Ethernet frame fully received yet.
 125  *           QCAFRM_NOHEAD       Header expected but not found.
 126  *           QCAFRM_INVLEN       QCA7K frame length is invalid
 127  *           QCAFRM_NOTAIL       Footer expected but not found.
 128  *           > 0                 Number of byte in the fully received
 129  *                               Ethernet frame
 130  */
 131
 132 s32 qcafrm_fsm_decode(struct qcafrm_handle *handle, u8 *buf, u16 buf_len, u8 recv_byte);
 133
 134 #endif /* _QCA_FRAMING_H */