/*
        Copyright (C) 2004 - 2009 rt2x00 SourceForge Project
        <http://rt2x00.serialmonkey.com>

        This program is free software; you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation; either version 2 of the License, or
        (at your option) any later version.

        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.,
        59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*
        Module: rt2x00
        Abstract: rt2x00 queue datastructures and routines
 */

#ifndef RT2X00QUEUE_H
#define RT2X00QUEUE_H

#include <linux/prefetch.h>

/**
 * DOC: Entry frame size
 *
 * Ralink PCI devices demand the Frame size to be a multiple of 128 bytes,
 * for USB devices this restriction does not apply, but the value of
 * 2432 makes sense since it is big enough to contain the maximum fragment
 * size according to the ieee802.11 specs.
 * The aggregation size depends on support from the driver, but should
 * be something around 3840 bytes.
 */
#define DATA_FRAME_SIZE         2432
#define MGMT_FRAME_SIZE         256
#define AGGREGATION_SIZE        3840

/**
 * DOC: Number of entries per queue
 *
 * Under normal load without fragmentation, 12 entries are sufficient
 * without the queue being filled up to the maximum. When using fragmentation
 * and the queue threshold code, we need to add some additional margins to
 * make sure the queue will never (or only under extreme load) fill up
 * completely.
 * Since we don't use preallocated DMA, having a large number of queue entries
 * will have minimal impact on the memory requirements for the queue.
 */
#define RX_ENTRIES      24
#define TX_ENTRIES      24
#define BEACON_ENTRIES  1
#define ATIM_ENTRIES    8

/**
 * enum data_queue_qid: Queue identification
 *
 * @QID_AC_BE: AC BE queue
 * @QID_AC_BK: AC BK queue
 * @QID_AC_VI: AC VI queue
 * @QID_AC_VO: AC VO queue
 * @QID_HCCA: HCCA queue
 * @QID_MGMT: MGMT queue (prio queue)
 * @QID_RX: RX queue
 * @QID_OTHER: None of the above (don't use, only present for completeness)
 * @QID_BEACON: Beacon queue (value unspecified, don't send it to device)
 * @QID_ATIM: Atim queue (value unspeficied, don't send it to device)
 */
enum data_queue_qid {
        QID_AC_BE = 0,
        QID_AC_BK = 1,
        QID_AC_VI = 2,
        QID_AC_VO = 3,
        QID_HCCA = 4,
        QID_MGMT = 13,
        QID_RX = 14,
        QID_OTHER = 15,
        QID_BEACON,
        QID_ATIM,
};

/**
 * enum skb_frame_desc_flags: Flags for &struct skb_frame_desc
 *
 * @SKBDESC_DMA_MAPPED_RX: &skb_dma field has been mapped for RX
 * @SKBDESC_DMA_MAPPED_TX: &skb_dma field has been mapped for TX
 * @SKBDESC_IV_STRIPPED: Frame contained a IV/EIV provided by
 *      mac80211 but was stripped for processing by the driver.
 * @SKBDESC_L2_PADDED: Payload has been padded for 4-byte alignment,
 *      the padded bytes are located between header and payload.
 */
enum skb_frame_desc_flags {
        SKBDESC_DMA_MAPPED_RX = 1 << 0,
        SKBDESC_DMA_MAPPED_TX = 1 << 1,
        SKBDESC_IV_STRIPPED = 1 << 2,
        SKBDESC_L2_PADDED = 1 << 3
};

/**
 * struct skb_frame_desc: Descriptor information for the skb buffer
 *
 * This structure is placed over the driver_data array, this means that
 * this structure should not exceed the size of that array (40 bytes).
 *
 * @flags: Frame flags, see &enum skb_frame_desc_flags.
 * @desc_len: Length of the frame descriptor.
 * @tx_rate_idx: the index of the TX rate, used for TX status reporting
 * @tx_rate_flags: the TX rate flags, used for TX status reporting
 * @desc: Pointer to descriptor part of the frame.
 *      Note that this pointer could point to something outside
 *      of the scope of the skb->data pointer.
 * @iv: IV/EIV data used during encryption/decryption.
 * @skb_dma: (PCI-only) the DMA address associated with the sk buffer.
 * @entry: The entry to which this sk buffer belongs.
 */
struct skb_frame_desc {
        u8 flags;

        u8 desc_len;
        u8 tx_rate_idx;
        u8 tx_rate_flags;

        void *desc;

        __le32 iv[2];

        dma_addr_t skb_dma;

        struct queue_entry *entry;
};

/**
 * get_skb_frame_desc - Obtain the rt2x00 frame descriptor from a sk_buff.
 * @skb: &struct sk_buff from where we obtain the &struct skb_frame_desc
 */
static inline struct skb_frame_desc* get_skb_frame_desc(struct sk_buff *skb)
{
        BUILD_BUG_ON(sizeof(struct skb_frame_desc) >
                     IEEE80211_TX_INFO_DRIVER_DATA_SIZE);
        return (struct skb_frame_desc *)&IEEE80211_SKB_CB(skb)->driver_data;
}

/**
 * enum rxdone_entry_desc_flags: Flags for &struct rxdone_entry_desc
 *
 * @RXDONE_SIGNAL_PLCP: Signal field contains the plcp value.
 * @RXDONE_SIGNAL_BITRATE: Signal field contains the bitrate value.
 * @RXDONE_SIGNAL_MCS: Signal field contains the mcs value.
 * @RXDONE_MY_BSS: Does this frame originate from device's BSS.
 * @RXDONE_CRYPTO_IV: Driver provided IV/EIV data.
 * @RXDONE_CRYPTO_ICV: Driver provided ICV data.
 * @RXDONE_L2PAD: 802.11 payload has been padded to 4-byte boundary.
 */
enum rxdone_entry_desc_flags {
        RXDONE_SIGNAL_PLCP = BIT(0),
        RXDONE_SIGNAL_BITRATE = BIT(1),
        RXDONE_SIGNAL_MCS = BIT(2),
        RXDONE_MY_BSS = BIT(3),
        RXDONE_CRYPTO_IV = BIT(4),
        RXDONE_CRYPTO_ICV = BIT(5),
        RXDONE_L2PAD = BIT(6),
};

/**
 * RXDONE_SIGNAL_MASK - Define to mask off all &rxdone_entry_desc_flags flags
 * except for the RXDONE_SIGNAL_* flags. This is useful to convert the dev_flags
 * from &rxdone_entry_desc to a signal value type.
 */
#define RXDONE_SIGNAL_MASK \
        ( RXDONE_SIGNAL_PLCP | RXDONE_SIGNAL_BITRATE | RXDONE_SIGNAL_MCS )

/**
 * struct rxdone_entry_desc: RX Entry descriptor
 *
 * Summary of information that has been read from the RX frame descriptor.
 *
 * @timestamp: RX Timestamp
 * @signal: Signal of the received frame.
 * @rssi: RSSI of the received frame.
 * @noise: Measured noise during frame reception.
 * @size: Data size of the received frame.
 * @flags: MAC80211 receive flags (See &enum mac80211_rx_flags).
 * @dev_flags: Ralink receive flags (See &enum rxdone_entry_desc_flags).
 * @rate_mode: Rate mode (See @enum rate_modulation).
 * @cipher: Cipher type used during decryption.
 * @cipher_status: Decryption status.
 * @iv: IV/EIV data used during decryption.
 * @icv: ICV data used during decryption.
 */
struct rxdone_entry_desc {
        u64 timestamp;
        int signal;
        int rssi;
        int noise;
        int size;
        int flags;
        int dev_flags;
        u16 rate_mode;
        u8 cipher;
        u8 cipher_status;

        __le32 iv[2];
        __le32 icv;
};

/**
 * enum txdone_entry_desc_flags: Flags for &struct txdone_entry_desc
 *
 * @TXDONE_UNKNOWN: Hardware could not determine success of transmission.
 * @TXDONE_SUCCESS: Frame was successfully send
 * @TXDONE_FALLBACK: Frame was successfully send using a fallback rate.
 * @TXDONE_FAILURE: Frame was not successfully send
 * @TXDONE_EXCESSIVE_RETRY: In addition to &TXDONE_FAILURE, the
 *      frame transmission failed due to excessive retries.
 */
enum txdone_entry_desc_flags {
        TXDONE_UNKNOWN,
        TXDONE_SUCCESS,
        TXDONE_FALLBACK,
        TXDONE_FAILURE,
        TXDONE_EXCESSIVE_RETRY,
};

/**
 * struct txdone_entry_desc: TX done entry descriptor
 *
 * Summary of information that has been read from the TX frame descriptor
 * after the device is done with transmission.
 *
 * @flags: TX done flags (See &enum txdone_entry_desc_flags).
 * @retry: Retry count.
 */
struct txdone_entry_desc {
        unsigned long flags;
        int retry;
};

/**
 * enum txentry_desc_flags: Status flags for TX entry descriptor
 *
 * @ENTRY_TXD_RTS_FRAME: This frame is a RTS frame.
 * @ENTRY_TXD_CTS_FRAME: This frame is a CTS-to-self frame.
 * @ENTRY_TXD_GENERATE_SEQ: This frame requires sequence counter.
 * @ENTRY_TXD_FIRST_FRAGMENT: This is the first frame.
 * @ENTRY_TXD_MORE_FRAG: This frame is followed by another fragment.
 * @ENTRY_TXD_REQ_TIMESTAMP: Require timestamp to be inserted.
 * @ENTRY_TXD_BURST: This frame belongs to the same burst event.
 * @ENTRY_TXD_ACK: An ACK is required for this frame.
 * @ENTRY_TXD_RETRY_MODE: When set, the long retry count is used.
 * @ENTRY_TXD_ENCRYPT: This frame should be encrypted.
 * @ENTRY_TXD_ENCRYPT_PAIRWISE: Use pairwise key table (instead of shared).
 * @ENTRY_TXD_ENCRYPT_IV: Generate IV/EIV in hardware.
 * @ENTRY_TXD_ENCRYPT_MMIC: Generate MIC in hardware.
 * @ENTRY_TXD_HT_AMPDU: This frame is part of an AMPDU.
 * @ENTRY_TXD_HT_BW_40: Use 40MHz Bandwidth.
 * @ENTRY_TXD_HT_SHORT_GI: Use short GI.
 */
enum txentry_desc_flags {
        ENTRY_TXD_RTS_FRAME,
        ENTRY_TXD_CTS_FRAME,
        ENTRY_TXD_GENERATE_SEQ,
        ENTRY_TXD_FIRST_FRAGMENT,
        ENTRY_TXD_MORE_FRAG,
        ENTRY_TXD_REQ_TIMESTAMP,
        ENTRY_TXD_BURST,
        ENTRY_TXD_ACK,
        ENTRY_TXD_RETRY_MODE,
        ENTRY_TXD_ENCRYPT,
        ENTRY_TXD_ENCRYPT_PAIRWISE,
        ENTRY_TXD_ENCRYPT_IV,
        ENTRY_TXD_ENCRYPT_MMIC,
        ENTRY_TXD_HT_AMPDU,
        ENTRY_TXD_HT_BW_40,
        ENTRY_TXD_HT_SHORT_GI,
};

/**
 * struct txentry_desc: TX Entry descriptor
 *
 * Summary of information for the frame descriptor before sending a TX frame.
 *
 * @flags: Descriptor flags (See &enum queue_entry_flags).
 * @queue: Queue identification (See &enum data_queue_qid).
 * @header_length: Length of 802.11 header.
 * @l2pad: Amount of padding to align 802.11 payload to 4-byte boundrary.
 * @length_high: PLCP length high word.
 * @length_low: PLCP length low word.
 * @signal: PLCP signal.
 * @service: PLCP service.
 * @msc: MCS.
 * @stbc: STBC.
 * @ba_size: BA size.
 * @rate_mode: Rate mode (See @enum rate_modulation).
 * @mpdu_density: MDPU density.
 * @retry_limit: Max number of retries.
 * @aifs: AIFS value.
 * @ifs: IFS value.
 * @cw_min: cwmin value.
 * @cw_max: cwmax value.
 * @cipher: Cipher type used for encryption.
 * @key_idx: Key index used for encryption.
 * @iv_offset: Position where IV should be inserted by hardware.
 * @iv_len: Length of IV data.
 */
struct txentry_desc {
        unsigned long flags;

        enum data_queue_qid queue;

        u16 header_length;
        u16 l2pad;

        u16 length_high;
        u16 length_low;
        u16 signal;
        u16 service;

        u16 mcs;
        u16 stbc;
        u16 ba_size;
        u16 rate_mode;
        u16 mpdu_density;

        short retry_limit;
        short aifs;
        short ifs;
        short cw_min;
        short cw_max;

        enum cipher cipher;
        u16 key_idx;
        u16 iv_offset;
        u16 iv_len;
};

/**
 * enum queue_entry_flags: Status flags for queue entry
 *
 * @ENTRY_BCN_ASSIGNED: This entry has been assigned to an interface.
 *      As long as this bit is set, this entry may only be touched
 *      through the interface structure.
 * @ENTRY_OWNER_DEVICE_DATA: This entry is owned by the device for data
 *      transfer (either TX or RX depending on the queue). The entry should
 *      only be touched after the device has signaled it is done with it.
 * @ENTRY_OWNER_DEVICE_CRYPTO: This entry is owned by the device for data
 *      encryption or decryption. The entry should only be touched after
 *      the device has signaled it is done with it.
 * @ENTRY_DATA_PENDING: This entry contains a valid frame and is waiting
 *      for the signal to start sending.
 */
enum queue_entry_flags {
        ENTRY_BCN_ASSIGNED,
        ENTRY_OWNER_DEVICE_DATA,
        ENTRY_OWNER_DEVICE_CRYPTO,
        ENTRY_DATA_PENDING,
};

/**
 * struct queue_entry: Entry inside the &struct data_queue
 *
 * @flags: Entry flags, see &enum queue_entry_flags.
 * @queue: The data queue (&struct data_queue) to which this entry belongs.
 * @skb: The buffer which is currently being transmitted (for TX queue),
 *      or used to directly recieve data in (for RX queue).
 * @entry_idx: The entry index number.
 * @priv_data: Private data belonging to this queue entry. The pointer
 *      points to data specific to a particular driver and queue type.
 */
struct queue_entry {
        unsigned long flags;

        struct data_queue *queue;

        struct sk_buff *skb;

        unsigned int entry_idx;

        void *priv_data;
};

/**
 * enum queue_index: Queue index type
 *
 * @Q_INDEX: Index pointer to the current entry in the queue, if this entry is
 *      owned by the hardware then the queue is considered to be full.
 * @Q_INDEX_DONE: Index pointer to the next entry which will be completed by
 *      the hardware and for which we need to run the txdone handler. If this
 *      entry is not owned by the hardware the queue is considered to be empty.
 * @Q_INDEX_CRYPTO: Index pointer to the next entry which encryption/decription
 *      will be completed by the hardware next.
 * @Q_INDEX_MAX: Keep last, used in &struct data_queue to determine the size
 *      of the index array.
 */
enum queue_index {
        Q_INDEX,
        Q_INDEX_DONE,
        Q_INDEX_CRYPTO,
        Q_INDEX_MAX,
};

/**
 * struct data_queue: Data queue
 *
 * @rt2x00dev: Pointer to main &struct rt2x00dev where this queue belongs to.
 * @entries: Base address of the &struct queue_entry which are
 *      part of this queue.
 * @qid: The queue identification, see &enum data_queue_qid.
 * @lock: Spinlock to protect index handling. Whenever @index, @index_done or
 *      @index_crypt needs to be changed this lock should be grabbed to prevent
 *      index corruption due to concurrency.
 * @count: Number of frames handled in the queue.
 * @limit: Maximum number of entries in the queue.
 * @threshold: Minimum number of free entries before queue is kicked by force.
 * @length: Number of frames in queue.
 * @index: Index pointers to entry positions in the queue,
 *      use &enum queue_index to get a specific index field.
 * @txop: maximum burst time.
 * @aifs: The aifs value for outgoing frames (field ignored in RX queue).
 * @cw_min: The cw min value for outgoing frames (field ignored in RX queue).
 * @cw_max: The cw max value for outgoing frames (field ignored in RX queue).
 * @data_size: Maximum data size for the frames in this queue.
 * @desc_size: Hardware descriptor size for the data in this queue.
 * @usb_endpoint: Device endpoint used for communication (USB only)
 * @usb_maxpacket: Max packet size for given endpoint (USB only)
 */
struct data_queue {
        struct rt2x00_dev *rt2x00dev;
        struct queue_entry *entries;

        enum data_queue_qid qid;

        spinlock_t lock;
        unsigned int count;
        unsigned short limit;
        unsigned short threshold;
        unsigned short length;
        unsigned short index[Q_INDEX_MAX];

        unsigned short txop;
        unsigned short aifs;
        unsigned short cw_min;
        unsigned short cw_max;

        unsigned short data_size;
        unsigned short desc_size;

        unsigned short usb_endpoint;
        unsigned short usb_maxpacket;
};

/**
 * struct data_queue_desc: Data queue description
 *
 * The information in this structure is used by drivers
 * to inform rt2x00lib about the creation of the data queue.
 *
 * @entry_num: Maximum number of entries for a queue.
 * @data_size: Maximum data size for the frames in this queue.
 * @desc_size: Hardware descriptor size for the data in this queue.
 * @priv_size: Size of per-queue_entry private data.
 */
struct data_queue_desc {
        unsigned short entry_num;
        unsigned short data_size;
        unsigned short desc_size;
        unsigned short priv_size;
};

/**
 * queue_end - Return pointer to the last queue (HELPER MACRO).
 * @__dev: Pointer to &struct rt2x00_dev
 *
 * Using the base rx pointer and the maximum number of available queues,
 * this macro will return the address of 1 position beyond  the end of the
 * queues array.
 */
#define queue_end(__dev) \
        &(__dev)->rx[(__dev)->data_queues]

/**
 * tx_queue_end - Return pointer to the last TX queue (HELPER MACRO).
 * @__dev: Pointer to &struct rt2x00_dev
 *
 * Using the base tx pointer and the maximum number of available TX
 * queues, this macro will return the address of 1 position beyond
 * the end of the TX queue array.
 */
#define tx_queue_end(__dev) \
        &(__dev)->tx[(__dev)->ops->tx_queues]

/**
 * queue_next - Return pointer to next queue in list (HELPER MACRO).
 * @__queue: Current queue for which we need the next queue
 *
 * Using the current queue address we take the address directly
 * after the queue to take the next queue. Note that this macro
 * should be used carefully since it does not protect against
 * moving past the end of the list. (See macros &queue_end and
 * &tx_queue_end for determining the end of the queue).
 */
#define queue_next(__queue) \
        &(__queue)[1]

/**
 * queue_loop - Loop through the queues within a specific range (HELPER MACRO).
 * @__entry: Pointer where the current queue entry will be stored in.
 * @__start: Start queue pointer.
 * @__end: End queue pointer.
 *
 * This macro will loop through all queues between &__start and &__end.
 */
#define queue_loop(__entry, __start, __end)                     \
        for ((__entry) = (__start);                             \
             prefetch(queue_next(__entry)), (__entry) != (__end);\
             (__entry) = queue_next(__entry))

/**
 * queue_for_each - Loop through all queues
 * @__dev: Pointer to &struct rt2x00_dev
 * @__entry: Pointer where the current queue entry will be stored in.
 *
 * This macro will loop through all available queues.
 */
#define queue_for_each(__dev, __entry) \
        queue_loop(__entry, (__dev)->rx, queue_end(__dev))

/**
 * tx_queue_for_each - Loop through the TX queues
 * @__dev: Pointer to &struct rt2x00_dev
 * @__entry: Pointer where the current queue entry will be stored in.
 *
 * This macro will loop through all TX related queues excluding
 * the Beacon and Atim queues.
 */
#define tx_queue_for_each(__dev, __entry) \
        queue_loop(__entry, (__dev)->tx, tx_queue_end(__dev))

/**
 * txall_queue_for_each - Loop through all TX related queues
 * @__dev: Pointer to &struct rt2x00_dev
 * @__entry: Pointer where the current queue entry will be stored in.
 *
 * This macro will loop through all TX related queues including
 * the Beacon and Atim queues.
 */
#define txall_queue_for_each(__dev, __entry) \
        queue_loop(__entry, (__dev)->tx, queue_end(__dev))

/**
 * rt2x00queue_empty - Check if the queue is empty.
 * @queue: Queue to check if empty.
 */
static inline int rt2x00queue_empty(struct data_queue *queue)
{
        return queue->length == 0;
}

/**
 * rt2x00queue_full - Check if the queue is full.
 * @queue: Queue to check if full.
 */
static inline int rt2x00queue_full(struct data_queue *queue)
{
        return queue->length == queue->limit;
}

/**
 * rt2x00queue_free - Check the number of available entries in queue.
 * @queue: Queue to check.
 */
static inline int rt2x00queue_available(struct data_queue *queue)
{
        return queue->limit - queue->length;
}

/**
 * rt2x00queue_threshold - Check if the queue is below threshold
 * @queue: Queue to check.
 */
static inline int rt2x00queue_threshold(struct data_queue *queue)
{
        return rt2x00queue_available(queue) < queue->threshold;
}

/**
 * _rt2x00_desc_read - Read a word from the hardware descriptor.
 * @desc: Base descriptor address
 * @word: Word index from where the descriptor should be read.
 * @value: Address where the descriptor value should be written into.
 */
static inline void _rt2x00_desc_read(__le32 *desc, const u8 word, __le32 *value)
{
        *value = desc[word];
}

/**
 * rt2x00_desc_read - Read a word from the hardware descriptor, this
 * function will take care of the byte ordering.
 * @desc: Base descriptor address
 * @word: Word index from where the descriptor should be read.
 * @value: Address where the descriptor value should be written into.
 */
static inline void rt2x00_desc_read(__le32 *desc, const u8 word, u32 *value)
{
        __le32 tmp;
        _rt2x00_desc_read(desc, word, &tmp);
        *value = le32_to_cpu(tmp);
}

/**
 * rt2x00_desc_write - write a word to the hardware descriptor, this
 * function will take care of the byte ordering.
 * @desc: Base descriptor address
 * @word: Word index from where the descriptor should be written.
 * @value: Value that should be written into the descriptor.
 */
static inline void _rt2x00_desc_write(__le32 *desc, const u8 word, __le32 value)
{
        desc[word] = value;
}

/**
 * rt2x00_desc_write - write a word to the hardware descriptor.
 * @desc: Base descriptor address
 * @word: Word index from where the descriptor should be written.
 * @value: Value that should be written into the descriptor.
 */
static inline void rt2x00_desc_write(__le32 *desc, const u8 word, u32 value)
{
        _rt2x00_desc_write(desc, word, cpu_to_le32(value));
}

#endif /* RT2X00QUEUE_H */