/**********************************************************************
 * Author: Cavium, Inc.
 *
 * Contact: support@cavium.com
 *          Please include "LiquidIO" in the subject.
 *
 * Copyright (c) 2003-2016 Cavium, Inc.
 *
 * This file 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 file is distributed in the hope that it will be useful, but
 * AS-IS and WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, TITLE, or
 * NONINFRINGEMENT.  See the GNU General Public License for more details.
 ***********************************************************************/
/*!  \file  octeon_droq.h
 *   \brief Implementation of Octeon Output queues. "Output" is with
 *   respect to the Octeon device on the NIC. From this driver's point of
 *   view they are ingress queues.
 */

#ifndef __OCTEON_DROQ_H__
#define __OCTEON_DROQ_H__

/* Default number of packets that will be processed in one iteration. */
#define MAX_PACKET_BUDGET 0xFFFFFFFF

/** Octeon descriptor format.
 *  The descriptor ring is made of descriptors which have 2 64-bit values:
 *  -# Physical (bus) address of the data buffer.
 *  -# Physical (bus) address of a octeon_droq_info structure.
 *  The Octeon device DMA's incoming packets and its information at the address
 *  given by these descriptor fields.
 */
struct octeon_droq_desc {
        /** The buffer pointer */
        u64 buffer_ptr;

        /** The Info pointer */
        u64 info_ptr;
};

#define OCT_DROQ_DESC_SIZE    (sizeof(struct octeon_droq_desc))

/** Information about packet DMA'ed by Octeon.
 *  The format of the information available at Info Pointer after Octeon
 *  has posted a packet. Not all descriptors have valid information. Only
 *  the Info field of the first descriptor for a packet has information
 *  about the packet.
 */
struct octeon_droq_info {
        /** The Length of the packet. */
        u64 length;

        /** The Output Receive Header. */
        union octeon_rh rh;
};

#define OCT_DROQ_INFO_SIZE   (sizeof(struct octeon_droq_info))

struct octeon_skb_page_info {
        /* DMA address for the page */
        dma_addr_t dma;

        /* Page for the rx dma  **/
        struct page *page;

        /** which offset into page */
        unsigned int page_offset;
};

/** Pointer to data buffer.
 *  Driver keeps a pointer to the data buffer that it made available to
 *  the Octeon device. Since the descriptor ring keeps physical (bus)
 *  addresses, this field is required for the driver to keep track of
 *  the virtual address pointers.
 */
struct octeon_recv_buffer {
        /** Packet buffer, including metadata. */
        void *buffer;

        /** Data in the packet buffer.  */
        u8 *data;

        /** pg_info **/
        struct octeon_skb_page_info pg_info;
};

#define OCT_DROQ_RECVBUF_SIZE    (sizeof(struct octeon_recv_buffer))

/** Output Queue statistics. Each output queue has four stats fields. */
struct oct_droq_stats {
        /** Number of packets received in this queue. */
        u64 pkts_received;

        /** Bytes received by this queue. */
        u64 bytes_received;

        /** Packets dropped due to no dispatch function. */
        u64 dropped_nodispatch;

        /** Packets dropped due to no memory available. */
        u64 dropped_nomem;

        /** Packets dropped due to large number of pkts to process. */
        u64 dropped_toomany;

        /** Number of packets  sent to stack from this queue. */
        u64 rx_pkts_received;

        /** Number of Bytes sent to stack from this queue. */
        u64 rx_bytes_received;

        /** Num of Packets dropped due to receive path failures. */
        u64 rx_dropped;

        u64 rx_vxlan;

        /** Num of failures of recv_buffer_alloc() */
        u64 rx_alloc_failure;

};

#define POLL_EVENT_INTR_ARRIVED  1
#define POLL_EVENT_PROCESS_PKTS  2
#define POLL_EVENT_PENDING_PKTS  3
#define POLL_EVENT_ENABLE_INTR   4

/* The maximum number of buffers that can be dispatched from the
 * output/dma queue. Set to 64 assuming 1K buffers in DROQ and the fact that
 * max packet size from DROQ is 64K.
 */
#define    MAX_RECV_BUFS    64

/** Receive Packet format used when dispatching output queue packets
 *  with non-raw opcodes.
 *  The received packet will be sent to the upper layers using this
 *  structure which is passed as a parameter to the dispatch function
 */
struct octeon_recv_pkt {
        /**  Number of buffers in this received packet */
        u16 buffer_count;

        /** Id of the device that is sending the packet up */
        u16 octeon_id;

        /** Length of data in the packet buffer */
        u32 length;

        /** The receive header */
        union octeon_rh rh;

        /** Pointer to the OS-specific packet buffer */
        void *buffer_ptr[MAX_RECV_BUFS];

        /** Size of the buffers pointed to by ptr's in buffer_ptr */
        u32 buffer_size[MAX_RECV_BUFS];
};

#define OCT_RECV_PKT_SIZE    (sizeof(struct octeon_recv_pkt))

/** The first parameter of a dispatch function.
 *  For a raw mode opcode, the driver dispatches with the device
 *  pointer in this structure.
 *  For non-raw mode opcode, the driver dispatches the recv_pkt
 *  created to contain the buffers with data received from Octeon.
 *  ---------------------
 *  |     *recv_pkt ----|---
 *  |-------------------|   |
 *  | 0 or more bytes   |   |
 *  | reserved by driver|   |
 *  |-------------------|<-/
 *  | octeon_recv_pkt   |
 *  |                   |
 *  |___________________|
 */
struct octeon_recv_info {
        void *rsvd;
        struct octeon_recv_pkt *recv_pkt;
};

#define  OCT_RECV_INFO_SIZE    (sizeof(struct octeon_recv_info))

/** Allocate a recv_info structure. The recv_pkt pointer in the recv_info
 *  structure is filled in before this call returns.
 *  @param extra_bytes - extra bytes to be allocated at the end of the recv info
 *                       structure.
 *  @return - pointer to a newly allocated recv_info structure.
 */
static inline struct octeon_recv_info *octeon_alloc_recv_info(int extra_bytes)
{
        struct octeon_recv_info *recv_info;
        u8 *buf;

        buf = kmalloc(OCT_RECV_PKT_SIZE + OCT_RECV_INFO_SIZE +
                      extra_bytes, GFP_ATOMIC);
        if (!buf)
                return NULL;

        recv_info = (struct octeon_recv_info *)buf;
        recv_info->recv_pkt =
                (struct octeon_recv_pkt *)(buf + OCT_RECV_INFO_SIZE);
        recv_info->rsvd = NULL;
        if (extra_bytes)
                recv_info->rsvd = buf + OCT_RECV_INFO_SIZE + OCT_RECV_PKT_SIZE;

        return recv_info;
}

/** Free a recv_info structure.
 *  @param recv_info - Pointer to receive_info to be freed
 */
static inline void octeon_free_recv_info(struct octeon_recv_info *recv_info)
{
        kfree(recv_info);
}

typedef int (*octeon_dispatch_fn_t)(struct octeon_recv_info *, void *);

/** Used by NIC module to register packet handler and to get device
 * information for each octeon device.
 */
struct octeon_droq_ops {
        /** This registered function will be called by the driver with
         *  the octeon id, pointer to buffer from droq and length of
         *  data in the buffer. The receive header gives the port
         *  number to the caller.  Function pointer is set by caller.
         */
        void (*fptr)(u32, void *, u32, union octeon_rh *, void *, void *);
        void *farg;

        /* This function will be called by the driver for all NAPI related
         * events. The first param is the octeon id. The second param is the
         * output queue number. The third is the NAPI event that occurred.
         */
        void (*napi_fn)(void *);

        u32 poll_mode;

        /** Flag indicating if the DROQ handler should drop packets that
         *  it cannot handle in one iteration. Set by caller.
         */
        u32 drop_on_max;
};

/** The Descriptor Ring Output Queue structure.
 *  This structure has all the information required to implement a
 *  Octeon DROQ.
 */
struct octeon_droq {
        /** A spinlock to protect access to this ring. */
        spinlock_t lock;

        u32 q_no;

        u32 pkt_count;

        struct octeon_droq_ops ops;

        struct octeon_device *oct_dev;

        /** The 8B aligned descriptor ring starts at this address. */
        struct octeon_droq_desc *desc_ring;

        /** Index in the ring where the driver should read the next packet */
        u32 read_idx;

        /** Index in the ring where Octeon will write the next packet */
        u32 write_idx;

        /** Index in the ring where the driver will refill the descriptor's
         * buffer
         */
        u32 refill_idx;

        /** Packets pending to be processed */
        atomic_t pkts_pending;

        /** Number of  descriptors in this ring. */
        u32 max_count;

        /** The number of descriptors pending refill. */
        u32 refill_count;

        u32 pkts_per_intr;
        u32 refill_threshold;

        /** The max number of descriptors in DROQ without a buffer.
         * This field is used to keep track of empty space threshold. If the
         * refill_count reaches this value, the DROQ cannot accept a max-sized
         * (64K) packet.
         */
        u32 max_empty_descs;

        /** The receive buffer list. This list has the virtual addresses of the
         * buffers.
         */
        struct octeon_recv_buffer *recv_buf_list;

        /** The size of each buffer pointed by the buffer pointer. */
        u32 buffer_size;

        /** Pointer to the mapped packet credit register.
         * Host writes number of info/buffer ptrs available to this register
         */
        void  __iomem *pkts_credit_reg;

        /** Pointer to the mapped packet sent register.
         * Octeon writes the number of packets DMA'ed to host memory
         * in this register.
         */
        void __iomem *pkts_sent_reg;

        struct list_head dispatch_list;

        /** Statistics for this DROQ. */
        struct oct_droq_stats stats;

        /** DMA mapped address of the DROQ descriptor ring. */
        size_t desc_ring_dma;

        /** application context */
        void *app_ctx;

        struct napi_struct napi;

        u32 cpu_id;

        call_single_data_t csd;
};

#define OCT_DROQ_SIZE   (sizeof(struct octeon_droq))

/**
 *  Allocates space for the descriptor ring for the droq and sets the
 *   base addr, num desc etc in Octeon registers.
 *
 * @param  oct_dev    - pointer to the octeon device structure
 * @param  q_no       - droq no. ranges from 0 - 3.
 * @param app_ctx     - pointer to application context
 * @return Success: 0    Failure: 1
 */
int octeon_init_droq(struct octeon_device *oct_dev,
                     u32 q_no,
                     u32 num_descs,
                     u32 desc_size,
                     void *app_ctx);

/**
 *  Frees the space for descriptor ring for the droq.
 *
 *  @param oct_dev - pointer to the octeon device structure
 *  @param q_no    - droq no. ranges from 0 - 3.
 *  @return:    Success: 0    Failure: 1
 */
int octeon_delete_droq(struct octeon_device *oct_dev, u32 q_no);

/** Register a change in droq operations. The ops field has a pointer to a
 * function which will called by the DROQ handler for all packets arriving
 * on output queues given by q_no irrespective of the type of packet.
 * The ops field also has a flag which if set tells the DROQ handler to
 * drop packets if it receives more than what it can process in one
 * invocation of the handler.
 * @param oct       - octeon device
 * @param q_no      - octeon output queue number (0 <= q_no <= MAX_OCTEON_DROQ-1
 * @param ops       - the droq_ops settings for this queue
 * @return          - 0 on success, -ENODEV or -EINVAL on error.
 */
int
octeon_register_droq_ops(struct octeon_device *oct,
                         u32 q_no,
                         struct octeon_droq_ops *ops);

/** Resets the function pointer and flag settings made by
 * octeon_register_droq_ops(). After this routine is called, the DROQ handler
 * will lookup dispatch function for each arriving packet on the output queue
 * given by q_no.
 * @param oct       - octeon device
 * @param q_no      - octeon output queue number (0 <= q_no <= MAX_OCTEON_DROQ-1
 * @return          - 0 on success, -ENODEV or -EINVAL on error.
 */
int octeon_unregister_droq_ops(struct octeon_device *oct, u32 q_no);

/**   Register a dispatch function for a opcode/subcode. The driver will call
 *    this dispatch function when it receives a packet with the given
 *    opcode/subcode in its output queues along with the user specified
 *    argument.
 *    @param  oct        - the octeon device to register with.
 *    @param  opcode     - the opcode for which the dispatch will be registered.
 *    @param  subcode    - the subcode for which the dispatch will be registered
 *    @param  fn         - the dispatch function.
 *    @param  fn_arg     - user specified that will be passed along with the
 *                         dispatch function by the driver.
 *    @return Success: 0; Failure: 1
 */
int octeon_register_dispatch_fn(struct octeon_device *oct,
                                u16 opcode,
                                u16 subcode,
                                octeon_dispatch_fn_t fn, void *fn_arg);

void octeon_droq_print_stats(void);

u32 octeon_droq_check_hw_for_pkts(struct octeon_droq *droq);

int octeon_create_droq(struct octeon_device *oct, u32 q_no,
                       u32 num_descs, u32 desc_size, void *app_ctx);

int octeon_droq_process_packets(struct octeon_device *oct,
                                struct octeon_droq *droq,
                                u32 budget);

int octeon_process_droq_poll_cmd(struct octeon_device *oct, u32 q_no,
                                 int cmd, u32 arg);

void octeon_droq_check_oom(struct octeon_droq *droq);

#endif  /*__OCTEON_DROQ_H__ */