tx.h

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/*
 * This file is part of wl1251
 *
 * Copyright (c) 1998-2007 Texas Instruments Incorporated
 * Copyright (C) 2008 Nokia Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#ifndef __WL1251_TX_H__
#define __WL1251_TX_H__

#include <linux/bitops.h>
#include "acx.h"

/*
 *
 * TX PATH
 *
 * The Tx path uses a double buffer and a tx_control structure, each located
 * at a fixed address in the device's memory. On startup, the host retrieves
 * the pointers to these addresses. A double buffer allows for continuous data
 * flow towards the device. The host keeps track of which buffer is available
 * and alternates between these two buffers on a per packet basis.
 *
 * The size of each of the two buffers is large enough to hold the longest
 * 802.3 packet - maximum size Ethernet packet + header + descriptor.
 * TX complete indication will be received a-synchronously in a TX done cyclic
 * buffer which is composed of 16 tx_result descriptors structures and is used
 * in a cyclic manner.
 *
 * The TX (HOST) procedure is as follows:
 * 1. Read the Tx path status, that will give the data_out_count.
 * 2. goto 1, if not possible.
 *    i.e. if data_in_count - data_out_count >= HwBuffer size (2 for double
 *    buffer).
 * 3. Copy the packet (preceded by double_buffer_desc), if possible.
 *    i.e. if data_in_count - data_out_count < HwBuffer size (2 for double
 *    buffer).
 * 4. increment data_in_count.
 * 5. Inform the firmware by generating a firmware internal interrupt.
 * 6. FW will increment data_out_count after it reads the buffer.
 *
 * The TX Complete procedure:
 * 1. To get a TX complete indication the host enables the tx_complete flag in
 *    the TX descriptor Structure.
 * 2. For each packet with a Tx Complete field set, the firmware adds the
 *    transmit results to the cyclic buffer (txDoneRing) and sets both done_1
 *    and done_2 to 1 to indicate driver ownership.
 * 3. The firmware sends a Tx Complete interrupt to the host to trigger the
 *    host to process the new data. Note: interrupt will be send per packet if
 *    TX complete indication was requested in tx_control or per crossing
 *    aggregation threshold.
 * 4. After receiving the Tx Complete interrupt, the host reads the
 *    TxDescriptorDone information in a cyclic manner and clears both done_1
 *    and done_2 fields.
 *
 */

#define TX_COMPLETE_REQUIRED_BIT    0x80
#define TX_STATUS_DATA_OUT_COUNT_MASK   0xf

#define WL1251_TX_ALIGN_TO 4
#define WL1251_TX_ALIGN(len) (((len) + WL1251_TX_ALIGN_TO - 1) & \
                 ~(WL1251_TX_ALIGN_TO - 1))
#define WL1251_TKIP_IV_SPACE 4

struct tx_control {
    /* Rate Policy (class) index */
    unsigned rate_policy:3;

    /* When set, no ack policy is expected */
    unsigned ack_policy:1;

    /*
     * Packet type:
     * 0 -> 802.11
     * 1 -> 802.3
     * 2 -> IP
     * 3 -> raw codec
     */
    unsigned packet_type:2;

    /* If set, this is a QoS-Null or QoS-Data frame */
    unsigned qos:1;

    /*
     * If set, the target triggers the tx complete INT
     * upon frame sending completion.
     */
    unsigned tx_complete:1;

    /* 2 bytes padding before packet header */
    unsigned xfer_pad:1;

    unsigned reserved:7;
} __packed;


struct tx_double_buffer_desc {
    /* Length of payload, including headers. */
    __le16 length;

    /*
     * A bit mask that specifies the initial rate to be used
     * Possible values are:
     * 0x0001 - 1Mbits
     * 0x0002 - 2Mbits
     * 0x0004 - 5.5Mbits
     * 0x0008 - 6Mbits
     * 0x0010 - 9Mbits
     * 0x0020 - 11Mbits
     * 0x0040 - 12Mbits
     * 0x0080 - 18Mbits
     * 0x0100 - 22Mbits
     * 0x0200 - 24Mbits
     * 0x0400 - 36Mbits
     * 0x0800 - 48Mbits
     * 0x1000 - 54Mbits
     */
    __le16 rate;

    /* Time in us that a packet can spend in the target */
    __le32 expiry_time;

    /* index of the TX queue used for this packet */
    u8 xmit_queue;

    /* Used to identify a packet */
    u8 id;

    struct tx_control control;

    /*
     * The FW should cut the packet into fragments
     * of this size.
     */
    __le16 frag_threshold;

    /* Numbers of HW queue blocks to be allocated */
    u8 num_mem_blocks;

    u8 reserved;
} __packed;

enum {
    TX_SUCCESS              = 0,
    TX_DMA_ERROR            = BIT(7),
    TX_DISABLED             = BIT(6),
    TX_RETRY_EXCEEDED       = BIT(5),
    TX_TIMEOUT              = BIT(4),
    TX_KEY_NOT_FOUND        = BIT(3),
    TX_ENCRYPT_FAIL         = BIT(2),
    TX_UNAVAILABLE_PRIORITY = BIT(1),
};

struct tx_result {
    /*
     * Ownership synchronization between the host and
     * the firmware. If done_1 and done_2 are cleared,
     * owned by the FW (no info ready).
     */
    u8 done_1;

    /* same as double_buffer_desc->id */
    u8 id;

    /*
     * Total air access duration consumed by this
     * packet, including all retries and overheads.
     */
    u16 medium_usage;

    /* Total media delay (from 1st EDCA AIFS counter until TX Complete). */
    u32 medium_delay;

    /* Time between host xfer and tx complete */
    u32 fw_hnadling_time;

    /* The LS-byte of the last TKIP sequence number. */
    u8 lsb_seq_num;

    /* Retry count */
    u8 ack_failures;

    /* At which rate we got a ACK */
    u16 rate;

    u16 reserved;

    /* TX_* */
    u8 status;

    /* See done_1 */
    u8 done_2;
} __packed;

static inline int wl1251_tx_get_queue(int queue)
{
    switch (queue) {
    case 0:
        return QOS_AC_VO;
    case 1:
        return QOS_AC_VI;
    case 2:
        return QOS_AC_BE;
    case 3:
        return QOS_AC_BK;
    default:
        return QOS_AC_BE;
    }
}

void wl1251_tx_work(struct work_struct *work);
void wl1251_tx_complete(struct wl1251 *wl);
void wl1251_tx_flush(struct wl1251 *wl);

#endif