154 lines
3.5 KiB
C
154 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
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/*
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* Copyright (c) 2011, 2012, Atheros Communications Inc.
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* Copyright (c) 2014, I2SE GmbH
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*/
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/* Atheros ethernet framing. Every Ethernet frame is surrounded
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* by an atheros frame while transmitted over a serial channel;
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include "qca_7k_common.h"
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u16
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qcafrm_create_header(u8 *buf, u16 length)
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{
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__le16 len;
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if (!buf)
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return 0;
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len = cpu_to_le16(length);
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buf[0] = 0xAA;
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buf[1] = 0xAA;
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buf[2] = 0xAA;
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buf[3] = 0xAA;
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buf[4] = len & 0xff;
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buf[5] = (len >> 8) & 0xff;
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buf[6] = 0;
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buf[7] = 0;
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return QCAFRM_HEADER_LEN;
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}
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EXPORT_SYMBOL_GPL(qcafrm_create_header);
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u16
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qcafrm_create_footer(u8 *buf)
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{
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if (!buf)
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return 0;
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buf[0] = 0x55;
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buf[1] = 0x55;
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return QCAFRM_FOOTER_LEN;
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}
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EXPORT_SYMBOL_GPL(qcafrm_create_footer);
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/* Gather received bytes and try to extract a full ethernet frame by
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* following a simple state machine.
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*
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* Return: QCAFRM_GATHER No ethernet frame fully received yet.
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* QCAFRM_NOHEAD Header expected but not found.
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* QCAFRM_INVLEN Atheros frame length is invalid
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* QCAFRM_NOTAIL Footer expected but not found.
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* > 0 Number of byte in the fully received
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* Ethernet frame
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*/
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s32
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qcafrm_fsm_decode(struct qcafrm_handle *handle, u8 *buf, u16 buf_len, u8 recv_byte)
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{
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s32 ret = QCAFRM_GATHER;
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u16 len;
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switch (handle->state) {
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case QCAFRM_HW_LEN0:
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case QCAFRM_HW_LEN1:
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/* by default, just go to next state */
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handle->state--;
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if (recv_byte != 0x00) {
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/* first two bytes of length must be 0 */
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handle->state = handle->init;
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}
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break;
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case QCAFRM_HW_LEN2:
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case QCAFRM_HW_LEN3:
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handle->state--;
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break;
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/* 4 bytes header pattern */
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case QCAFRM_WAIT_AA1:
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case QCAFRM_WAIT_AA2:
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case QCAFRM_WAIT_AA3:
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case QCAFRM_WAIT_AA4:
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if (recv_byte != 0xAA) {
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ret = QCAFRM_NOHEAD;
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handle->state = handle->init;
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} else {
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handle->state--;
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}
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break;
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/* 2 bytes length. */
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/* Borrow offset field to hold length for now. */
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case QCAFRM_WAIT_LEN_BYTE0:
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handle->offset = recv_byte;
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handle->state = QCAFRM_WAIT_LEN_BYTE1;
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break;
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case QCAFRM_WAIT_LEN_BYTE1:
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handle->offset = handle->offset | (recv_byte << 8);
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handle->state = QCAFRM_WAIT_RSVD_BYTE1;
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break;
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case QCAFRM_WAIT_RSVD_BYTE1:
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handle->state = QCAFRM_WAIT_RSVD_BYTE2;
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break;
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case QCAFRM_WAIT_RSVD_BYTE2:
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len = handle->offset;
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if (len > buf_len || len < QCAFRM_MIN_LEN) {
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ret = QCAFRM_INVLEN;
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handle->state = handle->init;
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} else {
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handle->state = (enum qcafrm_state)(len + 1);
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/* Remaining number of bytes. */
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handle->offset = 0;
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}
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break;
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default:
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/* Receiving Ethernet frame itself. */
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buf[handle->offset] = recv_byte;
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handle->offset++;
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handle->state--;
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break;
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case QCAFRM_WAIT_551:
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if (recv_byte != 0x55) {
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ret = QCAFRM_NOTAIL;
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handle->state = handle->init;
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} else {
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handle->state = QCAFRM_WAIT_552;
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}
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break;
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case QCAFRM_WAIT_552:
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if (recv_byte != 0x55) {
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ret = QCAFRM_NOTAIL;
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handle->state = handle->init;
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} else {
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ret = handle->offset;
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/* Frame is fully received. */
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handle->state = handle->init;
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}
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break;
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(qcafrm_fsm_decode);
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MODULE_DESCRIPTION("Qualcomm Atheros QCA7000 common");
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MODULE_AUTHOR("Qualcomm Atheros Communications");
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MODULE_AUTHOR("Stefan Wahren <wahrenst@gmx.net>");
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MODULE_LICENSE("Dual BSD/GPL");
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