[deliverable/linux.git] / drivers / net / ethernet / cavium / liquidio / request_manager.c

/**********************************************************************
 * Author: Cavium, Inc.
 *
 * Contact: support@cavium.com
 *          Please include "LiquidIO" in the subject.
 *
 * Copyright (c) 2003-2015 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.
 *
 * This file may also be available under a different license from Cavium.
 * Contact Cavium, Inc. for more information
 **********************************************************************/
#include <linux/version.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/kthread.h>
#include <linux/netdevice.h>
#include "octeon_config.h"
#include "liquidio_common.h"
#include "octeon_droq.h"
#include "octeon_iq.h"
#include "response_manager.h"
#include "octeon_device.h"
#include "octeon_nic.h"
#include "octeon_main.h"
#include "octeon_network.h"
#include "cn66xx_regs.h"
#include "cn66xx_device.h"
#include "cn68xx_regs.h"
#include "cn68xx_device.h"
#include "liquidio_image.h"

#define INCR_INSTRQUEUE_PKT_COUNT(octeon_dev_ptr, iq_no, field, count)  \
        (octeon_dev_ptr->instr_queue[iq_no]->stats.field += count)

struct iq_post_status {
        int status;
        int index;
};

static void check_db_timeout(struct work_struct *work);
static void  __check_db_timeout(struct octeon_device *oct, unsigned long iq_no);

static void (*reqtype_free_fn[MAX_OCTEON_DEVICES][REQTYPE_LAST + 1]) (void *);

static inline int IQ_INSTR_MODE_64B(struct octeon_device *oct, int iq_no)
{
        struct octeon_instr_queue *iq =
            (struct octeon_instr_queue *)oct->instr_queue[iq_no];
        return iq->iqcmd_64B;
}

#define IQ_INSTR_MODE_32B(oct, iq_no)  (!IQ_INSTR_MODE_64B(oct, iq_no))

/* Define this to return the request status comaptible to old code */
/*#define OCTEON_USE_OLD_REQ_STATUS*/

/* Return 0 on success, 1 on failure */
int octeon_init_instr_queue(struct octeon_device *oct,
                            u32 iq_no, u32 num_descs)
{
        struct octeon_instr_queue *iq;
        struct octeon_iq_config *conf = NULL;
        u32 q_size;
        struct cavium_wq *db_wq;

        if (OCTEON_CN6XXX(oct))
                conf = &(CFG_GET_IQ_CFG(CHIP_FIELD(oct, cn6xxx, conf)));

        if (!conf) {
                dev_err(&oct->pci_dev->dev, "Unsupported Chip %x\n",
                        oct->chip_id);
                return 1;
        }

        if (num_descs & (num_descs - 1)) {
                dev_err(&oct->pci_dev->dev,
                        "Number of descriptors for instr queue %d not in power of 2.\n",
                        iq_no);
                return 1;
        }

        q_size = (u32)conf->instr_type * num_descs;

        iq = oct->instr_queue[iq_no];

        iq->base_addr = lio_dma_alloc(oct, q_size,
                                      (dma_addr_t *)&iq->base_addr_dma);
        if (!iq->base_addr) {
                dev_err(&oct->pci_dev->dev, "Cannot allocate memory for instr queue %d\n",
                        iq_no);
                return 1;
        }

        iq->max_count = num_descs;

        /* Initialize a list to holds requests that have been posted to Octeon
         * but has yet to be fetched by octeon
         */
        iq->request_list = vmalloc(sizeof(*iq->request_list) * num_descs);
        if (!iq->request_list) {
                lio_dma_free(oct, q_size, iq->base_addr, iq->base_addr_dma);
                dev_err(&oct->pci_dev->dev, "Alloc failed for IQ[%d] nr free list\n",
                        iq_no);
                return 1;
        }

        memset(iq->request_list, 0, sizeof(*iq->request_list) * num_descs);

        dev_dbg(&oct->pci_dev->dev, "IQ[%d]: base: %p basedma: %llx count: %d\n",
                iq_no, iq->base_addr, iq->base_addr_dma, iq->max_count);

        iq->iq_no = iq_no;
        iq->fill_threshold = (u32)conf->db_min;
        iq->fill_cnt = 0;
        iq->host_write_index = 0;
        iq->octeon_read_index = 0;
        iq->flush_index = 0;
        iq->last_db_time = 0;
        iq->do_auto_flush = 1;
        iq->db_timeout = (u32)conf->db_timeout;
        atomic_set(&iq->instr_pending, 0);

        /* Initialize the spinlock for this instruction queue */
        spin_lock_init(&iq->lock);

        oct->io_qmask.iq |= (1 << iq_no);

        /* Set the 32B/64B mode for each input queue */
        oct->io_qmask.iq64B |= ((conf->instr_type == 64) << iq_no);
        iq->iqcmd_64B = (conf->instr_type == 64);

        oct->fn_list.setup_iq_regs(oct, iq_no);

        oct->check_db_wq[iq_no].wq = create_workqueue("check_iq_db");
        if (!oct->check_db_wq[iq_no].wq) {
                lio_dma_free(oct, q_size, iq->base_addr, iq->base_addr_dma);
                dev_err(&oct->pci_dev->dev, "check db wq create failed for iq %d\n",
                        iq_no);
                return 1;
        }

        db_wq = &oct->check_db_wq[iq_no];

        INIT_DELAYED_WORK(&db_wq->wk.work, check_db_timeout);
        db_wq->wk.ctxptr = oct;
        db_wq->wk.ctxul = iq_no;
        queue_delayed_work(db_wq->wq, &db_wq->wk.work, msecs_to_jiffies(1));

        return 0;
}

int octeon_delete_instr_queue(struct octeon_device *oct, u32 iq_no)
{
        u64 desc_size = 0, q_size;
        struct octeon_instr_queue *iq = oct->instr_queue[iq_no];

        cancel_delayed_work_sync(&oct->check_db_wq[iq_no].wk.work);
        flush_workqueue(oct->check_db_wq[iq_no].wq);
        destroy_workqueue(oct->check_db_wq[iq_no].wq);

        if (OCTEON_CN6XXX(oct))
                desc_size =
                    CFG_GET_IQ_INSTR_TYPE(CHIP_FIELD(oct, cn6xxx, conf));

        if (iq->request_list)
                vfree(iq->request_list);

        if (iq->base_addr) {
                q_size = iq->max_count * desc_size;
                lio_dma_free(oct, (u32)q_size, iq->base_addr,
                             iq->base_addr_dma);
                return 0;
        }
        return 1;
}

/* Return 0 on success, 1 on failure */
int octeon_setup_iq(struct octeon_device *oct,
                    u32 iq_no,
                    u32 num_descs,
                    void *app_ctx)
{
        if (oct->instr_queue[iq_no]) {
                dev_dbg(&oct->pci_dev->dev, "IQ is in use. Cannot create the IQ: %d again\n",
                        iq_no);
                oct->instr_queue[iq_no]->app_ctx = app_ctx;
                return 0;
        }
        oct->instr_queue[iq_no] =
            vmalloc(sizeof(struct octeon_instr_queue));
        if (!oct->instr_queue[iq_no])
                return 1;

        memset(oct->instr_queue[iq_no], 0,
               sizeof(struct octeon_instr_queue));

        oct->instr_queue[iq_no]->app_ctx = app_ctx;
        if (octeon_init_instr_queue(oct, iq_no, num_descs)) {
                vfree(oct->instr_queue[iq_no]);
                oct->instr_queue[iq_no] = NULL;
                return 1;
        }

        oct->num_iqs++;
        oct->fn_list.enable_io_queues(oct);
        return 0;
}

int lio_wait_for_instr_fetch(struct octeon_device *oct)
{
        int i, retry = 1000, pending, instr_cnt = 0;

        do {
                instr_cnt = 0;

                /*for (i = 0; i < oct->num_iqs; i++) {*/
                for (i = 0; i < MAX_OCTEON_INSTR_QUEUES; i++) {
                        if (!(oct->io_qmask.iq & (1UL << i)))
                                continue;
                        pending =
                            atomic_read(&oct->
                                               instr_queue[i]->instr_pending);
                        if (pending)
                                __check_db_timeout(oct, i);
                        instr_cnt += pending;
                }

                if (instr_cnt == 0)
                        break;

                schedule_timeout_uninterruptible(1);

        } while (retry-- && instr_cnt);

        return instr_cnt;
}

static inline void
ring_doorbell(struct octeon_device *oct, struct octeon_instr_queue *iq)
{
        if (atomic_read(&oct->status) == OCT_DEV_RUNNING) {
                writel(iq->fill_cnt, iq->doorbell_reg);
                /* make sure doorbell write goes through */
                mmiowb();
                iq->fill_cnt = 0;
                iq->last_db_time = jiffies;
                return;
        }
}

static inline void __copy_cmd_into_iq(struct octeon_instr_queue *iq,
                                      u8 *cmd)
{
        u8 *iqptr, cmdsize;

        cmdsize = ((iq->iqcmd_64B) ? 64 : 32);
        iqptr = iq->base_addr + (cmdsize * iq->host_write_index);

        memcpy(iqptr, cmd, cmdsize);
}

static inline int
__post_command(struct octeon_device *octeon_dev __attribute__((unused)),
               struct octeon_instr_queue *iq,
               u32 force_db __attribute__((unused)), u8 *cmd)
{
        u32 index = -1;

        /* This ensures that the read index does not wrap around to the same
         * position if queue gets full before Octeon could fetch any instr.
         */
        if (atomic_read(&iq->instr_pending) >= (s32)(iq->max_count - 1))
                return -1;

        __copy_cmd_into_iq(iq, cmd);

        /* "index" is returned, host_write_index is modified. */
        index = iq->host_write_index;
        INCR_INDEX_BY1(iq->host_write_index, iq->max_count);
        iq->fill_cnt++;

        /* Flush the command into memory. We need to be sure the data is in
         * memory before indicating that the instruction is pending.
         */
        wmb();

        atomic_inc(&iq->instr_pending);

        return index;
}

static inline struct iq_post_status
__post_command2(struct octeon_device *octeon_dev __attribute__((unused)),
                struct octeon_instr_queue *iq,
                u32 force_db __attribute__((unused)), u8 *cmd)
{
        struct iq_post_status st;

        st.status = IQ_SEND_OK;

        /* This ensures that the read index does not wrap around to the same
         * position if queue gets full before Octeon could fetch any instr.
         */
        if (atomic_read(&iq->instr_pending) >= (s32)(iq->max_count - 1)) {
                st.status = IQ_SEND_FAILED;
                st.index = -1;
                return st;
        }

        if (atomic_read(&iq->instr_pending) >= (s32)(iq->max_count - 2))
                st.status = IQ_SEND_STOP;

        __copy_cmd_into_iq(iq, cmd);

        /* "index" is returned, host_write_index is modified. */
        st.index = iq->host_write_index;
        INCR_INDEX_BY1(iq->host_write_index, iq->max_count);
        iq->fill_cnt++;

        /* Flush the command into memory. We need to be sure the data is in
         * memory before indicating that the instruction is pending.
         */
        wmb();

        atomic_inc(&iq->instr_pending);

        return st;
}

int
octeon_register_reqtype_free_fn(struct octeon_device *oct, int reqtype,
                                void (*fn)(void *))
{
        if (reqtype > REQTYPE_LAST) {
                dev_err(&oct->pci_dev->dev, "%s: Invalid reqtype: %d\n",
                        __func__, reqtype);
                return -EINVAL;
        }

        reqtype_free_fn[oct->octeon_id][reqtype] = fn;

        return 0;
}

static inline void
__add_to_request_list(struct octeon_instr_queue *iq,
                      int idx, void *buf, int reqtype)
{
        iq->request_list[idx].buf = buf;
        iq->request_list[idx].reqtype = reqtype;
}

int
lio_process_iq_request_list(struct octeon_device *oct,
                            struct octeon_instr_queue *iq)
{
        int reqtype;
        void *buf;
        u32 old = iq->flush_index;
        u32 inst_count = 0;
        unsigned pkts_compl = 0, bytes_compl = 0;
        struct octeon_soft_command *sc;
        struct octeon_instr_irh *irh;

        while (old != iq->octeon_read_index) {
                reqtype = iq->request_list[old].reqtype;
                buf     = iq->request_list[old].buf;

                if (reqtype == REQTYPE_NONE)
                        goto skip_this;

                octeon_update_tx_completion_counters(buf, reqtype, &pkts_compl,
                                                     &bytes_compl);

                switch (reqtype) {
                case REQTYPE_NORESP_NET:
                case REQTYPE_NORESP_NET_SG:
                case REQTYPE_RESP_NET_SG:
                        reqtype_free_fn[oct->octeon_id][reqtype](buf);
                        break;
                case REQTYPE_RESP_NET:
                case REQTYPE_SOFT_COMMAND:
                        sc = buf;

                        irh = (struct octeon_instr_irh *)&sc->cmd.irh;
                        if (irh->rflag) {
                                /* We're expecting a response from Octeon.
                                 * It's up to lio_process_ordered_list() to
                                 * process  sc. Add sc to the ordered soft
                                 * command response list because we expect
                                 * a response from Octeon.
                                 */
                                spin_lock_bh(&oct->response_list
                                        [OCTEON_ORDERED_SC_LIST].lock);
                                atomic_inc(&oct->response_list
                                        [OCTEON_ORDERED_SC_LIST].
                                        pending_req_count);
                                list_add_tail(&sc->node, &oct->response_list
                                        [OCTEON_ORDERED_SC_LIST].head);
                                spin_unlock_bh(&oct->response_list
                                        [OCTEON_ORDERED_SC_LIST].lock);
                        } else {
                                if (sc->callback) {
                                        sc->callback(oct, OCTEON_REQUEST_DONE,
                                                     sc->callback_arg);
                                }
                        }
                        break;
                default:
                        dev_err(&oct->pci_dev->dev,
                                "%s Unknown reqtype: %d buf: %p at idx %d\n",
                                __func__, reqtype, buf, old);
                }

                iq->request_list[old].buf = NULL;
                iq->request_list[old].reqtype = 0;

 skip_this:
                inst_count++;
                INCR_INDEX_BY1(old, iq->max_count);
        }
        if (bytes_compl)
                octeon_report_tx_completion_to_bql(iq->app_ctx, pkts_compl,
                                                   bytes_compl);
        iq->flush_index = old;

        return inst_count;
}

static inline void
update_iq_indices(struct octeon_device *oct, struct octeon_instr_queue *iq)
{
        u32 inst_processed = 0;

        /* Calculate how many commands Octeon has read and move the read index
         * accordingly.
         */
        iq->octeon_read_index = oct->fn_list.update_iq_read_idx(oct, iq);

        /* Move the NORESPONSE requests to the per-device completion list. */
        if (iq->flush_index != iq->octeon_read_index)
                inst_processed = lio_process_iq_request_list(oct, iq);

        if (inst_processed)
                atomic_sub(inst_processed, &iq->instr_pending);
                iq->stats.instr_processed += inst_processed;
}

static void
octeon_flush_iq(struct octeon_device *oct, struct octeon_instr_queue *iq,
                u32 pending_thresh)
{
        if (atomic_read(&iq->instr_pending) >= (s32)pending_thresh) {
                spin_lock_bh(&iq->lock);
                update_iq_indices(oct, iq);
                spin_unlock_bh(&iq->lock);
        }
}

static void __check_db_timeout(struct octeon_device *oct, unsigned long iq_no)
{
        struct octeon_instr_queue *iq;
        u64 next_time;

        if (!oct)
                return;
        iq = oct->instr_queue[iq_no];
        if (!iq)
                return;

        /* If jiffies - last_db_time < db_timeout do nothing  */
        next_time = iq->last_db_time + iq->db_timeout;
        if (!time_after(jiffies, (unsigned long)next_time))
                return;
        iq->last_db_time = jiffies;

        /* Get the lock and prevent tasklets. This routine gets called from
         * the poll thread. Instructions can now be posted in tasklet context
         */
        spin_lock_bh(&iq->lock);
        if (iq->fill_cnt != 0)
                ring_doorbell(oct, iq);

        spin_unlock_bh(&iq->lock);

        /* Flush the instruction queue */
        if (iq->do_auto_flush)
                octeon_flush_iq(oct, iq, 1);
}

/* Called by the Poll thread at regular intervals to check the instruction
 * queue for commands to be posted and for commands that were fetched by Octeon.
 */
static void check_db_timeout(struct work_struct *work)
{
        struct cavium_wk *wk = (struct cavium_wk *)work;
        struct octeon_device *oct = (struct octeon_device *)wk->ctxptr;
        unsigned long iq_no = wk->ctxul;
        struct cavium_wq *db_wq = &oct->check_db_wq[iq_no];

        __check_db_timeout(oct, iq_no);
        queue_delayed_work(db_wq->wq, &db_wq->wk.work, msecs_to_jiffies(1));
}

int
octeon_send_command(struct octeon_device *oct, u32 iq_no,
                    u32 force_db, void *cmd, void *buf,
                    u32 datasize, u32 reqtype)
{
        struct iq_post_status st;
        struct octeon_instr_queue *iq = oct->instr_queue[iq_no];

        spin_lock_bh(&iq->lock);

        st = __post_command2(oct, iq, force_db, cmd);

        if (st.status != IQ_SEND_FAILED) {
                octeon_report_sent_bytes_to_bql(buf, reqtype);
                __add_to_request_list(iq, st.index, buf, reqtype);
                INCR_INSTRQUEUE_PKT_COUNT(oct, iq_no, bytes_sent, datasize);
                INCR_INSTRQUEUE_PKT_COUNT(oct, iq_no, instr_posted, 1);

                if (iq->fill_cnt >= iq->fill_threshold || force_db)
                        ring_doorbell(oct, iq);
        } else {
                INCR_INSTRQUEUE_PKT_COUNT(oct, iq_no, instr_dropped, 1);
        }

        spin_unlock_bh(&iq->lock);

        if (iq->do_auto_flush)
                octeon_flush_iq(oct, iq, 2);

        return st.status;
}

void
octeon_prepare_soft_command(struct octeon_device *oct,
                            struct octeon_soft_command *sc,
                            u8 opcode,
                            u8 subcode,
                            u32 irh_ossp,
                            u64 ossp0,
                            u64 ossp1)
{
        struct octeon_config *oct_cfg;
        struct octeon_instr_ih *ih;
        struct octeon_instr_irh *irh;
        struct octeon_instr_rdp *rdp;

        BUG_ON(opcode > 15);
        BUG_ON(subcode > 127);

        oct_cfg = octeon_get_conf(oct);

        ih          = (struct octeon_instr_ih *)&sc->cmd.ih;
        ih->tagtype = ATOMIC_TAG;
        ih->tag     = LIO_CONTROL;
        ih->raw     = 1;
        ih->grp     = CFG_GET_CTRL_Q_GRP(oct_cfg);

        if (sc->datasize) {
                ih->dlengsz = sc->datasize;
                ih->rs = 1;
        }

        irh            = (struct octeon_instr_irh *)&sc->cmd.irh;
        irh->opcode    = opcode;
        irh->subcode   = subcode;

        /* opcode/subcode specific parameters (ossp) */
        irh->ossp       = irh_ossp;
        sc->cmd.ossp[0] = ossp0;
        sc->cmd.ossp[1] = ossp1;

        if (sc->rdatasize) {
                rdp            = (struct octeon_instr_rdp *)&sc->cmd.rdp;
                rdp->pcie_port = oct->pcie_port;
                rdp->rlen      = sc->rdatasize;

                irh->rflag =  1;
                irh->len   =  4;
                ih->fsz    = 40; /* irh+ossp[0]+ossp[1]+rdp+rptr = 40 bytes */
        } else {
                irh->rflag =  0;
                irh->len   =  2;
                ih->fsz    = 24; /* irh + ossp[0] + ossp[1] = 24 bytes */
        }

        while (!(oct->io_qmask.iq & (1 << sc->iq_no)))
                sc->iq_no++;
}

int octeon_send_soft_command(struct octeon_device *oct,
                             struct octeon_soft_command *sc)
{
        struct octeon_instr_ih *ih;
        struct octeon_instr_irh *irh;
        struct octeon_instr_rdp *rdp;

        ih = (struct octeon_instr_ih *)&sc->cmd.ih;
        if (ih->dlengsz) {
                BUG_ON(!sc->dmadptr);
                sc->cmd.dptr = sc->dmadptr;
        }

        irh = (struct octeon_instr_irh *)&sc->cmd.irh;
        if (irh->rflag) {
                BUG_ON(!sc->dmarptr);
                BUG_ON(!sc->status_word);
                *sc->status_word = COMPLETION_WORD_INIT;

                rdp = (struct octeon_instr_rdp *)&sc->cmd.rdp;

                sc->cmd.rptr = sc->dmarptr;
        }

        if (sc->wait_time)
                sc->timeout = jiffies + sc->wait_time;

        return octeon_send_command(oct, sc->iq_no, 1, &sc->cmd, sc,
                                   (u32)ih->dlengsz, REQTYPE_SOFT_COMMAND);
}

int octeon_setup_sc_buffer_pool(struct octeon_device *oct)
{
        int i;
        u64 dma_addr;
        struct octeon_soft_command *sc;

        INIT_LIST_HEAD(&oct->sc_buf_pool.head);
        spin_lock_init(&oct->sc_buf_pool.lock);
        atomic_set(&oct->sc_buf_pool.alloc_buf_count, 0);

        for (i = 0; i < MAX_SOFT_COMMAND_BUFFERS; i++) {
                sc = (struct octeon_soft_command *)
                        lio_dma_alloc(oct,
                                      SOFT_COMMAND_BUFFER_SIZE,
                                          (dma_addr_t *)&dma_addr);
                if (!sc)
                        return 1;

                sc->dma_addr = dma_addr;
                sc->size = SOFT_COMMAND_BUFFER_SIZE;

                list_add_tail(&sc->node, &oct->sc_buf_pool.head);
        }

        return 0;
}

int octeon_free_sc_buffer_pool(struct octeon_device *oct)
{
        struct list_head *tmp, *tmp2;
        struct octeon_soft_command *sc;

        spin_lock(&oct->sc_buf_pool.lock);

        list_for_each_safe(tmp, tmp2, &oct->sc_buf_pool.head) {
                list_del(tmp);

                sc = (struct octeon_soft_command *)tmp;

                lio_dma_free(oct, sc->size, sc, sc->dma_addr);
        }

        INIT_LIST_HEAD(&oct->sc_buf_pool.head);

        spin_unlock(&oct->sc_buf_pool.lock);

        return 0;
}

struct octeon_soft_command *octeon_alloc_soft_command(struct octeon_device *oct,
                                                      u32 datasize,
                                                      u32 rdatasize,
                                                      u32 ctxsize)
{
        u64 dma_addr;
        u32 size;
        u32 offset = sizeof(struct octeon_soft_command);
        struct octeon_soft_command *sc = NULL;
        struct list_head *tmp;

        BUG_ON((offset + datasize + rdatasize + ctxsize) >
               SOFT_COMMAND_BUFFER_SIZE);

        spin_lock(&oct->sc_buf_pool.lock);

        if (list_empty(&oct->sc_buf_pool.head)) {
                spin_unlock(&oct->sc_buf_pool.lock);
                return NULL;
        }

        list_for_each(tmp, &oct->sc_buf_pool.head)
                break;

        list_del(tmp);

        atomic_inc(&oct->sc_buf_pool.alloc_buf_count);

        spin_unlock(&oct->sc_buf_pool.lock);

        sc = (struct octeon_soft_command *)tmp;

        dma_addr = sc->dma_addr;
        size = sc->size;

        memset(sc, 0, sc->size);

        sc->dma_addr = dma_addr;
        sc->size = size;

        if (ctxsize) {
                sc->ctxptr = (u8 *)sc + offset;
                sc->ctxsize = ctxsize;
        }

        /* Start data at 128 byte boundary */
        offset = (offset + ctxsize + 127) & 0xffffff80;

        if (datasize) {
                sc->virtdptr = (u8 *)sc + offset;
                sc->dmadptr = dma_addr + offset;
                sc->datasize = datasize;
        }

        /* Start rdata at 128 byte boundary */
        offset = (offset + datasize + 127) & 0xffffff80;

        if (rdatasize) {
                BUG_ON(rdatasize < 16);
                sc->virtrptr = (u8 *)sc + offset;
                sc->dmarptr = dma_addr + offset;
                sc->rdatasize = rdatasize;
                sc->status_word = (u64 *)((u8 *)(sc->virtrptr) + rdatasize - 8);
        }

        return sc;
}

void octeon_free_soft_command(struct octeon_device *oct,
                              struct octeon_soft_command *sc)
{
        spin_lock(&oct->sc_buf_pool.lock);

        list_add_tail(&sc->node, &oct->sc_buf_pool.head);

        atomic_dec(&oct->sc_buf_pool.alloc_buf_count);

        spin_unlock(&oct->sc_buf_pool.lock);
}