cvmx-cmd-queue.h

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/***********************license start***************
 * Author: Cavium Networks
 *
 * Contact: [email protected]
 * This file is part of the OCTEON SDK
 *
 * Copyright (c) 2003-2008 Cavium Networks
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this file; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 * or visit http://www.gnu.org/licenses/.
 *
 * This file may also be available under a different license from Cavium.
 * Contact Cavium Networks for more information
 ***********************license end**************************************/

/*
 *
 * Support functions for managing command queues used for
 * various hardware blocks.
 *
 * The common command queue infrastructure abstracts out the
 * software necessary for adding to Octeon's chained queue
 * structures. These structures are used for commands to the
 * PKO, ZIP, DFA, RAID, and DMA engine blocks. Although each
 * hardware unit takes commands and CSRs of different types,
 * they all use basic linked command buffers to store the
 * pending request. In general, users of the CVMX API don't
 * call cvmx-cmd-queue functions directly. Instead the hardware
 * unit specific wrapper should be used. The wrappers perform
 * unit specific validation and CSR writes to submit the
 * commands.
 *
 * Even though most software will never directly interact with
 * cvmx-cmd-queue, knowledge of its internal working can help
 * in diagnosing performance problems and help with debugging.
 *
 * Command queue pointers are stored in a global named block
 * called "cvmx_cmd_queues". Except for the PKO queues, each
 * hardware queue is stored in its own cache line to reduce SMP
 * contention on spin locks. The PKO queues are stored such that
 * every 16th queue is next to each other in memory. This scheme
 * allows for queues being in separate cache lines when there
 * are low number of queues per port. With 16 queues per port,
 * the first queue for each port is in the same cache area. The
 * second queues for each port are in another area, etc. This
 * allows software to implement very efficient lockless PKO with
 * 16 queues per port using a minimum of cache lines per core.
 * All queues for a given core will be isolated in the same
 * cache area.
 *
 * In addition to the memory pointer layout, cvmx-cmd-queue
 * provides an optimized fair ll/sc locking mechanism for the
 * queues. The lock uses a "ticket / now serving" model to
 * maintain fair order on contended locks. In addition, it uses
 * predicted locking time to limit cache contention. When a core
 * know it must wait in line for a lock, it spins on the
 * internal cycle counter to completely eliminate any causes of
 * bus traffic.
 *
 */

#ifndef __CVMX_CMD_QUEUE_H__
#define __CVMX_CMD_QUEUE_H__

#include <linux/prefetch.h>

#include <asm/octeon/cvmx-fpa.h>
#ifndef CVMX_CMD_QUEUE_ENABLE_MAX_DEPTH
#define CVMX_CMD_QUEUE_ENABLE_MAX_DEPTH 0
#endif

typedef enum {
    CVMX_CMD_QUEUE_PKO_BASE = 0x00000,

#define CVMX_CMD_QUEUE_PKO(queue) \
    ((cvmx_cmd_queue_id_t)(CVMX_CMD_QUEUE_PKO_BASE + (0xffff&(queue))))

    CVMX_CMD_QUEUE_ZIP = 0x10000,
    CVMX_CMD_QUEUE_DFA = 0x20000,
    CVMX_CMD_QUEUE_RAID = 0x30000,
    CVMX_CMD_QUEUE_DMA_BASE = 0x40000,

#define CVMX_CMD_QUEUE_DMA(queue) \
    ((cvmx_cmd_queue_id_t)(CVMX_CMD_QUEUE_DMA_BASE + (0xffff&(queue))))

    CVMX_CMD_QUEUE_END = 0x50000,
} cvmx_cmd_queue_id_t;

typedef enum {
    CVMX_CMD_QUEUE_SUCCESS = 0,
    CVMX_CMD_QUEUE_NO_MEMORY = -1,
    CVMX_CMD_QUEUE_FULL = -2,
    CVMX_CMD_QUEUE_INVALID_PARAM = -3,
    CVMX_CMD_QUEUE_ALREADY_SETUP = -4,
} cvmx_cmd_queue_result_t;

typedef struct {
    /* You have lock when this is your ticket */
    uint8_t now_serving;
    uint64_t unused1:24;
    /* Maximum outstanding command words */
    uint32_t max_depth;
    /* FPA pool buffers come from */
    uint64_t fpa_pool:3;
    /* Top of command buffer pointer shifted 7 */
    uint64_t base_ptr_div128:29;
    uint64_t unused2:6;
    /* FPA buffer size in 64bit words minus 1 */
    uint64_t pool_size_m1:13;
    /* Number of commands already used in buffer */
    uint64_t index:13;
} __cvmx_cmd_queue_state_t;

typedef struct {
    uint64_t ticket[(CVMX_CMD_QUEUE_END >> 16) * 256];
    __cvmx_cmd_queue_state_t state[(CVMX_CMD_QUEUE_END >> 16) * 256];
} __cvmx_cmd_queue_all_state_t;

cvmx_cmd_queue_result_t cvmx_cmd_queue_initialize(cvmx_cmd_queue_id_t queue_id,
                          int max_depth, int fpa_pool,
                          int pool_size);

cvmx_cmd_queue_result_t cvmx_cmd_queue_shutdown(cvmx_cmd_queue_id_t queue_id);

int cvmx_cmd_queue_length(cvmx_cmd_queue_id_t queue_id);

void *cvmx_cmd_queue_buffer(cvmx_cmd_queue_id_t queue_id);

static inline int __cvmx_cmd_queue_get_index(cvmx_cmd_queue_id_t queue_id)
{
    /*
     * Warning: This code currently only works with devices that
     * have 256 queues or less. Devices with more than 16 queues
     * are laid out in memory to allow cores quick access to
     * every 16th queue. This reduces cache thrashing when you are
     * running 16 queues per port to support lockless operation.
     */
    int unit = queue_id >> 16;
    int q = (queue_id >> 4) & 0xf;
    int core = queue_id & 0xf;
    return unit * 256 + core * 16 + q;
}

static inline void __cvmx_cmd_queue_lock(cvmx_cmd_queue_id_t queue_id,
                     __cvmx_cmd_queue_state_t *qptr)
{
    extern __cvmx_cmd_queue_all_state_t
        *__cvmx_cmd_queue_state_ptr;
    int tmp;
    int my_ticket;
    prefetch(qptr);
    asm volatile (
        ".set push\n"
        ".set noreorder\n"
        "1:\n"
        /* Atomic add one to ticket_ptr */
        "ll     %[my_ticket], %[ticket_ptr]\n"
        /* and store the original value */
        "li     %[ticket], 1\n"
        /* in my_ticket */
        "baddu  %[ticket], %[my_ticket]\n"
        "sc     %[ticket], %[ticket_ptr]\n"
        "beqz   %[ticket], 1b\n"
        " nop\n"
        /* Load the current now_serving ticket */
        "lbu    %[ticket], %[now_serving]\n"
        "2:\n"
        /* Jump out if now_serving == my_ticket */
        "beq    %[ticket], %[my_ticket], 4f\n"
        /* Find out how many tickets are in front of me */
        " subu   %[ticket], %[my_ticket], %[ticket]\n"
        /* Use tickets in front of me minus one to delay */
        "subu  %[ticket], 1\n"
        /* Delay will be ((tickets in front)-1)*32 loops */
        "cins   %[ticket], %[ticket], 5, 7\n"
        "3:\n"
        /* Loop here until our ticket might be up */
        "bnez   %[ticket], 3b\n"
        " subu  %[ticket], 1\n"
        /* Jump back up to check out ticket again */
        "b      2b\n"
        /* Load the current now_serving ticket */
        " lbu   %[ticket], %[now_serving]\n"
        "4:\n"
        ".set pop\n" :
        [ticket_ptr] "=m"(__cvmx_cmd_queue_state_ptr->ticket[__cvmx_cmd_queue_get_index(queue_id)]),
        [now_serving] "=m"(qptr->now_serving), [ticket] "=r"(tmp),
        [my_ticket] "=r"(my_ticket)
        );
}

static inline void __cvmx_cmd_queue_unlock(__cvmx_cmd_queue_state_t *qptr)
{
    qptr->now_serving++;
    CVMX_SYNCWS;
}

static inline __cvmx_cmd_queue_state_t
    *__cvmx_cmd_queue_get_state(cvmx_cmd_queue_id_t queue_id)
{
    extern __cvmx_cmd_queue_all_state_t
        *__cvmx_cmd_queue_state_ptr;
    return &__cvmx_cmd_queue_state_ptr->
        state[__cvmx_cmd_queue_get_index(queue_id)];
}

static inline cvmx_cmd_queue_result_t cvmx_cmd_queue_write(cvmx_cmd_queue_id_t
                               queue_id,
                               int use_locking,
                               int cmd_count,
                               uint64_t *cmds)
{
    __cvmx_cmd_queue_state_t *qptr = __cvmx_cmd_queue_get_state(queue_id);

    /* Make sure nobody else is updating the same queue */
    if (likely(use_locking))
        __cvmx_cmd_queue_lock(queue_id, qptr);

    /*
     * If a max queue length was specified then make sure we don't
     * exceed it. If any part of the command would be below the
     * limit we allow it.
     */
    if (CVMX_CMD_QUEUE_ENABLE_MAX_DEPTH && unlikely(qptr->max_depth)) {
        if (unlikely
            (cvmx_cmd_queue_length(queue_id) > (int)qptr->max_depth)) {
            if (likely(use_locking))
                __cvmx_cmd_queue_unlock(qptr);
            return CVMX_CMD_QUEUE_FULL;
        }
    }

    /*
     * Normally there is plenty of room in the current buffer for
     * the command.
     */
    if (likely(qptr->index + cmd_count < qptr->pool_size_m1)) {
        uint64_t *ptr =
            (uint64_t *) cvmx_phys_to_ptr((uint64_t) qptr->
                          base_ptr_div128 << 7);
        ptr += qptr->index;
        qptr->index += cmd_count;
        while (cmd_count--)
            *ptr++ = *cmds++;
    } else {
        uint64_t *ptr;
        int count;
        /*
         * We need a new command buffer. Fail if there isn't
         * one available.
         */
        uint64_t *new_buffer =
            (uint64_t *) cvmx_fpa_alloc(qptr->fpa_pool);
        if (unlikely(new_buffer == NULL)) {
            if (likely(use_locking))
                __cvmx_cmd_queue_unlock(qptr);
            return CVMX_CMD_QUEUE_NO_MEMORY;
        }
        ptr =
            (uint64_t *) cvmx_phys_to_ptr((uint64_t) qptr->
                          base_ptr_div128 << 7);
        /*
         * Figure out how many command words will fit in this
         * buffer. One location will be needed for the next
         * buffer pointer.
         */
        count = qptr->pool_size_m1 - qptr->index;
        ptr += qptr->index;
        cmd_count -= count;
        while (count--)
            *ptr++ = *cmds++;
        *ptr = cvmx_ptr_to_phys(new_buffer);
        /*
         * The current buffer is full and has a link to the
         * next buffer. Time to write the rest of the commands
         * into the new buffer.
         */
        qptr->base_ptr_div128 = *ptr >> 7;
        qptr->index = cmd_count;
        ptr = new_buffer;
        while (cmd_count--)
            *ptr++ = *cmds++;
    }

    /* All updates are complete. Release the lock and return */
    if (likely(use_locking))
        __cvmx_cmd_queue_unlock(qptr);
    return CVMX_CMD_QUEUE_SUCCESS;
}

static inline cvmx_cmd_queue_result_t cvmx_cmd_queue_write2(cvmx_cmd_queue_id_t
                                queue_id,
                                int use_locking,
                                uint64_t cmd1,
                                uint64_t cmd2)
{
    __cvmx_cmd_queue_state_t *qptr = __cvmx_cmd_queue_get_state(queue_id);

    /* Make sure nobody else is updating the same queue */
    if (likely(use_locking))
        __cvmx_cmd_queue_lock(queue_id, qptr);

    /*
     * If a max queue length was specified then make sure we don't
     * exceed it. If any part of the command would be below the
     * limit we allow it.
     */
    if (CVMX_CMD_QUEUE_ENABLE_MAX_DEPTH && unlikely(qptr->max_depth)) {
        if (unlikely
            (cvmx_cmd_queue_length(queue_id) > (int)qptr->max_depth)) {
            if (likely(use_locking))
                __cvmx_cmd_queue_unlock(qptr);
            return CVMX_CMD_QUEUE_FULL;
        }
    }

    /*
     * Normally there is plenty of room in the current buffer for
     * the command.
     */
    if (likely(qptr->index + 2 < qptr->pool_size_m1)) {
        uint64_t *ptr =
            (uint64_t *) cvmx_phys_to_ptr((uint64_t) qptr->
                          base_ptr_div128 << 7);
        ptr += qptr->index;
        qptr->index += 2;
        ptr[0] = cmd1;
        ptr[1] = cmd2;
    } else {
        uint64_t *ptr;
        /*
         * Figure out how many command words will fit in this
         * buffer. One location will be needed for the next
         * buffer pointer.
         */
        int count = qptr->pool_size_m1 - qptr->index;
        /*
         * We need a new command buffer. Fail if there isn't
         * one available.
         */
        uint64_t *new_buffer =
            (uint64_t *) cvmx_fpa_alloc(qptr->fpa_pool);
        if (unlikely(new_buffer == NULL)) {
            if (likely(use_locking))
                __cvmx_cmd_queue_unlock(qptr);
            return CVMX_CMD_QUEUE_NO_MEMORY;
        }
        count--;
        ptr =
            (uint64_t *) cvmx_phys_to_ptr((uint64_t) qptr->
                          base_ptr_div128 << 7);
        ptr += qptr->index;
        *ptr++ = cmd1;
        if (likely(count))
            *ptr++ = cmd2;
        *ptr = cvmx_ptr_to_phys(new_buffer);
        /*
         * The current buffer is full and has a link to the
         * next buffer. Time to write the rest of the commands
         * into the new buffer.
         */
        qptr->base_ptr_div128 = *ptr >> 7;
        qptr->index = 0;
        if (unlikely(count == 0)) {
            qptr->index = 1;
            new_buffer[0] = cmd2;
        }
    }

    /* All updates are complete. Release the lock and return */
    if (likely(use_locking))
        __cvmx_cmd_queue_unlock(qptr);
    return CVMX_CMD_QUEUE_SUCCESS;
}

static inline cvmx_cmd_queue_result_t cvmx_cmd_queue_write3(cvmx_cmd_queue_id_t
                                queue_id,
                                int use_locking,
                                uint64_t cmd1,
                                uint64_t cmd2,
                                uint64_t cmd3)
{
    __cvmx_cmd_queue_state_t *qptr = __cvmx_cmd_queue_get_state(queue_id);

    /* Make sure nobody else is updating the same queue */
    if (likely(use_locking))
        __cvmx_cmd_queue_lock(queue_id, qptr);

    /*
     * If a max queue length was specified then make sure we don't
     * exceed it. If any part of the command would be below the
     * limit we allow it.
     */
    if (CVMX_CMD_QUEUE_ENABLE_MAX_DEPTH && unlikely(qptr->max_depth)) {
        if (unlikely
            (cvmx_cmd_queue_length(queue_id) > (int)qptr->max_depth)) {
            if (likely(use_locking))
                __cvmx_cmd_queue_unlock(qptr);
            return CVMX_CMD_QUEUE_FULL;
        }
    }

    /*
     * Normally there is plenty of room in the current buffer for
     * the command.
     */
    if (likely(qptr->index + 3 < qptr->pool_size_m1)) {
        uint64_t *ptr =
            (uint64_t *) cvmx_phys_to_ptr((uint64_t) qptr->
                          base_ptr_div128 << 7);
        ptr += qptr->index;
        qptr->index += 3;
        ptr[0] = cmd1;
        ptr[1] = cmd2;
        ptr[2] = cmd3;
    } else {
        uint64_t *ptr;
        /*
         * Figure out how many command words will fit in this
         * buffer. One location will be needed for the next
         * buffer pointer
         */
        int count = qptr->pool_size_m1 - qptr->index;
        /*
         * We need a new command buffer. Fail if there isn't
         * one available
         */
        uint64_t *new_buffer =
            (uint64_t *) cvmx_fpa_alloc(qptr->fpa_pool);
        if (unlikely(new_buffer == NULL)) {
            if (likely(use_locking))
                __cvmx_cmd_queue_unlock(qptr);
            return CVMX_CMD_QUEUE_NO_MEMORY;
        }
        count--;
        ptr =
            (uint64_t *) cvmx_phys_to_ptr((uint64_t) qptr->
                          base_ptr_div128 << 7);
        ptr += qptr->index;
        *ptr++ = cmd1;
        if (count) {
            *ptr++ = cmd2;
            if (count > 1)
                *ptr++ = cmd3;
        }
        *ptr = cvmx_ptr_to_phys(new_buffer);
        /*
         * The current buffer is full and has a link to the
         * next buffer. Time to write the rest of the commands
         * into the new buffer.
         */
        qptr->base_ptr_div128 = *ptr >> 7;
        qptr->index = 0;
        ptr = new_buffer;
        if (count == 0) {
            *ptr++ = cmd2;
            qptr->index++;
        }
        if (count < 2) {
            *ptr++ = cmd3;
            qptr->index++;
        }
    }

    /* All updates are complete. Release the lock and return */
    if (likely(use_locking))
        __cvmx_cmd_queue_unlock(qptr);
    return CVMX_CMD_QUEUE_SUCCESS;
}

#endif /* __CVMX_CMD_QUEUE_H__ */