diff options
Diffstat (limited to 'drivers/net/ethernet/qualcomm/qca_framing.c')
| -rw-r--r-- | drivers/net/ethernet/qualcomm/qca_framing.c | 156 |
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 00000000000..faa924c85e2 --- /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; +} |