initial commit with v2.6.32.60

[linux-2.6.32.60-moxart.git] / drivers / dma / ioat / dma_v3.c

/*
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2004 - 2009 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions 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.
 *
 * The full GNU General Public License is included in this distribution in
 * the file called "COPYING".
 *
 * BSD LICENSE
 *
 * Copyright(c) 2004-2009 Intel Corporation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Support routines for v3+ hardware
 */

#include <linux/pci.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include "registers.h"
#include "hw.h"
#include "dma.h"
#include "dma_v2.h"

/* ioat hardware assumes at least two sources for raid operations */
#define src_cnt_to_sw(x) ((x) + 2)
#define src_cnt_to_hw(x) ((x) - 2)

/* provide a lookup table for setting the source address in the base or
 * extended descriptor of an xor or pq descriptor
 */
static const u8 xor_idx_to_desc __read_mostly = 0xd0;
static const u8 xor_idx_to_field[] __read_mostly = { 1, 4, 5, 6, 7, 0, 1, 2 };
static const u8 pq_idx_to_desc __read_mostly = 0xf8;
static const u8 pq_idx_to_field[] __read_mostly = { 1, 4, 5, 0, 1, 2, 4, 5 };

static dma_addr_t xor_get_src(struct ioat_raw_descriptor *descs[2], int idx)
{
        struct ioat_raw_descriptor *raw = descs[xor_idx_to_desc >> idx & 1];

        return raw->field[xor_idx_to_field[idx]];
}

static void xor_set_src(struct ioat_raw_descriptor *descs[2],
                        dma_addr_t addr, u32 offset, int idx)
{
        struct ioat_raw_descriptor *raw = descs[xor_idx_to_desc >> idx & 1];

        raw->field[xor_idx_to_field[idx]] = addr + offset;
}

static dma_addr_t pq_get_src(struct ioat_raw_descriptor *descs[2], int idx)
{
        struct ioat_raw_descriptor *raw = descs[pq_idx_to_desc >> idx & 1];

        return raw->field[pq_idx_to_field[idx]];
}

static void pq_set_src(struct ioat_raw_descriptor *descs[2],
                       dma_addr_t addr, u32 offset, u8 coef, int idx)
{
        struct ioat_pq_descriptor *pq = (struct ioat_pq_descriptor *) descs[0];
        struct ioat_raw_descriptor *raw = descs[pq_idx_to_desc >> idx & 1];

        raw->field[pq_idx_to_field[idx]] = addr + offset;
        pq->coef[idx] = coef;
}

static void ioat3_dma_unmap(struct ioat2_dma_chan *ioat,
                            struct ioat_ring_ent *desc, int idx)
{
        struct ioat_chan_common *chan = &ioat->base;
        struct pci_dev *pdev = chan->device->pdev;
        size_t len = desc->len;
        size_t offset = len - desc->hw->size;
        struct dma_async_tx_descriptor *tx = &desc->txd;
        enum dma_ctrl_flags flags = tx->flags;

        switch (desc->hw->ctl_f.op) {
        case IOAT_OP_COPY:
                if (!desc->hw->ctl_f.null) /* skip 'interrupt' ops */
                        ioat_dma_unmap(chan, flags, len, desc->hw);
                break;
        case IOAT_OP_FILL: {
                struct ioat_fill_descriptor *hw = desc->fill;

                if (!(flags & DMA_COMPL_SKIP_DEST_UNMAP))
                        ioat_unmap(pdev, hw->dst_addr - offset, len,
                                   PCI_DMA_FROMDEVICE, flags, 1);
                break;
        }
        case IOAT_OP_XOR_VAL:
        case IOAT_OP_XOR: {
                struct ioat_xor_descriptor *xor = desc->xor;
                struct ioat_ring_ent *ext;
                struct ioat_xor_ext_descriptor *xor_ex = NULL;
                int src_cnt = src_cnt_to_sw(xor->ctl_f.src_cnt);
                struct ioat_raw_descriptor *descs[2];
                int i;

                if (src_cnt > 5) {
                        ext = ioat2_get_ring_ent(ioat, idx + 1);
                        xor_ex = ext->xor_ex;
                }

                if (!(flags & DMA_COMPL_SKIP_SRC_UNMAP)) {
                        descs[0] = (struct ioat_raw_descriptor *) xor;
                        descs[1] = (struct ioat_raw_descriptor *) xor_ex;
                        for (i = 0; i < src_cnt; i++) {
                                dma_addr_t src = xor_get_src(descs, i);

                                ioat_unmap(pdev, src - offset, len,
                                           PCI_DMA_TODEVICE, flags, 0);
                        }

                        /* dest is a source in xor validate operations */
                        if (xor->ctl_f.op == IOAT_OP_XOR_VAL) {
                                ioat_unmap(pdev, xor->dst_addr - offset, len,
                                           PCI_DMA_TODEVICE, flags, 1);
                                break;
                        }
                }

                if (!(flags & DMA_COMPL_SKIP_DEST_UNMAP))
                        ioat_unmap(pdev, xor->dst_addr - offset, len,
                                   PCI_DMA_FROMDEVICE, flags, 1);
                break;
        }
        case IOAT_OP_PQ_VAL:
        case IOAT_OP_PQ: {
                struct ioat_pq_descriptor *pq = desc->pq;
                struct ioat_ring_ent *ext;
                struct ioat_pq_ext_descriptor *pq_ex = NULL;
                int src_cnt = src_cnt_to_sw(pq->ctl_f.src_cnt);
                struct ioat_raw_descriptor *descs[2];
                int i;

                if (src_cnt > 3) {
                        ext = ioat2_get_ring_ent(ioat, idx + 1);
                        pq_ex = ext->pq_ex;
                }

                /* in the 'continue' case don't unmap the dests as sources */
                if (dmaf_p_disabled_continue(flags))
                        src_cnt--;
                else if (dmaf_continue(flags))
                        src_cnt -= 3;

                if (!(flags & DMA_COMPL_SKIP_SRC_UNMAP)) {
                        descs[0] = (struct ioat_raw_descriptor *) pq;
                        descs[1] = (struct ioat_raw_descriptor *) pq_ex;
                        for (i = 0; i < src_cnt; i++) {
                                dma_addr_t src = pq_get_src(descs, i);

                                ioat_unmap(pdev, src - offset, len,
                                           PCI_DMA_TODEVICE, flags, 0);
                        }

                        /* the dests are sources in pq validate operations */
                        if (pq->ctl_f.op == IOAT_OP_XOR_VAL) {
                                if (!(flags & DMA_PREP_PQ_DISABLE_P))
                                        ioat_unmap(pdev, pq->p_addr - offset,
                                                   len, PCI_DMA_TODEVICE, flags, 0);
                                if (!(flags & DMA_PREP_PQ_DISABLE_Q))
                                        ioat_unmap(pdev, pq->q_addr - offset,
                                                   len, PCI_DMA_TODEVICE, flags, 0);
                                break;
                        }
                }

                if (!(flags & DMA_COMPL_SKIP_DEST_UNMAP)) {
                        if (!(flags & DMA_PREP_PQ_DISABLE_P))
                                ioat_unmap(pdev, pq->p_addr - offset, len,
                                           PCI_DMA_BIDIRECTIONAL, flags, 1);
                        if (!(flags & DMA_PREP_PQ_DISABLE_Q))
                                ioat_unmap(pdev, pq->q_addr - offset, len,
                                           PCI_DMA_BIDIRECTIONAL, flags, 1);
                }
                break;
        }
        default:
                dev_err(&pdev->dev, "%s: unknown op type: %#x\n",
                        __func__, desc->hw->ctl_f.op);
        }
}

static bool desc_has_ext(struct ioat_ring_ent *desc)
{
        struct ioat_dma_descriptor *hw = desc->hw;

        if (hw->ctl_f.op == IOAT_OP_XOR ||
            hw->ctl_f.op == IOAT_OP_XOR_VAL) {
                struct ioat_xor_descriptor *xor = desc->xor;

                if (src_cnt_to_sw(xor->ctl_f.src_cnt) > 5)
                        return true;
        } else if (hw->ctl_f.op == IOAT_OP_PQ ||
                   hw->ctl_f.op == IOAT_OP_PQ_VAL) {
                struct ioat_pq_descriptor *pq = desc->pq;

                if (src_cnt_to_sw(pq->ctl_f.src_cnt) > 3)
                        return true;
        }

        return false;
}

/**
 * __cleanup - reclaim used descriptors
 * @ioat: channel (ring) to clean
 *
 * The difference from the dma_v2.c __cleanup() is that this routine
 * handles extended descriptors and dma-unmapping raid operations.
 */
static void __cleanup(struct ioat2_dma_chan *ioat, unsigned long phys_complete)
{
        struct ioat_chan_common *chan = &ioat->base;
        struct ioat_ring_ent *desc;
        bool seen_current = false;
        u16 active;
        int i;

        dev_dbg(to_dev(chan), "%s: head: %#x tail: %#x issued: %#x\n",
                __func__, ioat->head, ioat->tail, ioat->issued);

        active = ioat2_ring_active(ioat);
        for (i = 0; i < active && !seen_current; i++) {
                struct dma_async_tx_descriptor *tx;

                prefetch(ioat2_get_ring_ent(ioat, ioat->tail + i + 1));
                desc = ioat2_get_ring_ent(ioat, ioat->tail + i);
                dump_desc_dbg(ioat, desc);
                tx = &desc->txd;
                if (tx->cookie) {
                        chan->completed_cookie = tx->cookie;
                        ioat3_dma_unmap(ioat, desc, ioat->tail + i);
                        tx->cookie = 0;
                        if (tx->callback) {
                                tx->callback(tx->callback_param);
                                tx->callback = NULL;
                        }
                }

                if (tx->phys == phys_complete)
                        seen_current = true;

                /* skip extended descriptors */
                if (desc_has_ext(desc)) {
                        BUG_ON(i + 1 >= active);
                        i++;
                }
        }
        ioat->tail += i;
        BUG_ON(!seen_current); /* no active descs have written a completion? */
        chan->last_completion = phys_complete;
        if (ioat->head == ioat->tail) {
                dev_dbg(to_dev(chan), "%s: cancel completion timeout\n",
                        __func__);
                clear_bit(IOAT_COMPLETION_PENDING, &chan->state);
                mod_timer(&chan->timer, jiffies + IDLE_TIMEOUT);
        }
}

static void ioat3_cleanup(struct ioat2_dma_chan *ioat)
{
        struct ioat_chan_common *chan = &ioat->base;
        unsigned long phys_complete;

        prefetch(chan->completion);

        if (!spin_trylock_bh(&chan->cleanup_lock))
                return;

        if (!ioat_cleanup_preamble(chan, &phys_complete)) {
                spin_unlock_bh(&chan->cleanup_lock);
                return;
        }

        if (!spin_trylock_bh(&ioat->ring_lock)) {
                spin_unlock_bh(&chan->cleanup_lock);
                return;
        }

        __cleanup(ioat, phys_complete);

        spin_unlock_bh(&ioat->ring_lock);
        spin_unlock_bh(&chan->cleanup_lock);
}

static void ioat3_cleanup_tasklet(unsigned long data)
{
        struct ioat2_dma_chan *ioat = (void *) data;

        ioat3_cleanup(ioat);
        writew(IOAT_CHANCTRL_RUN | IOAT3_CHANCTRL_COMPL_DCA_EN,
               ioat->base.reg_base + IOAT_CHANCTRL_OFFSET);
}

static void ioat3_restart_channel(struct ioat2_dma_chan *ioat)
{
        struct ioat_chan_common *chan = &ioat->base;
        unsigned long phys_complete;
        u32 status;

        status = ioat_chansts(chan);
        if (is_ioat_active(status) || is_ioat_idle(status))
                ioat_suspend(chan);
        while (is_ioat_active(status) || is_ioat_idle(status)) {
                status = ioat_chansts(chan);
                cpu_relax();
        }

        if (ioat_cleanup_preamble(chan, &phys_complete))
                __cleanup(ioat, phys_complete);

        __ioat2_restart_chan(ioat);
}

static void ioat3_timer_event(unsigned long data)
{
        struct ioat2_dma_chan *ioat = (void *) data;
        struct ioat_chan_common *chan = &ioat->base;

        spin_lock_bh(&chan->cleanup_lock);
        if (test_bit(IOAT_COMPLETION_PENDING, &chan->state)) {
                unsigned long phys_complete;
                u64 status;

                spin_lock_bh(&ioat->ring_lock);
                status = ioat_chansts(chan);

                /* when halted due to errors check for channel
                 * programming errors before advancing the completion state
                 */
                if (is_ioat_halted(status)) {
                        u32 chanerr;

                        chanerr = readl(chan->reg_base + IOAT_CHANERR_OFFSET);
                        dev_err(to_dev(chan), "%s: Channel halted (%x)\n",
                                __func__, chanerr);
                        BUG_ON(is_ioat_bug(chanerr));
                }

                /* if we haven't made progress and we have already
                 * acknowledged a pending completion once, then be more
                 * forceful with a restart
                 */
                if (ioat_cleanup_preamble(chan, &phys_complete))
                        __cleanup(ioat, phys_complete);
                else if (test_bit(IOAT_COMPLETION_ACK, &chan->state))
                        ioat3_restart_channel(ioat);
                else {
                        set_bit(IOAT_COMPLETION_ACK, &chan->state);
                        mod_timer(&chan->timer, jiffies + COMPLETION_TIMEOUT);
                }
                spin_unlock_bh(&ioat->ring_lock);
        } else {
                u16 active;

                /* if the ring is idle, empty, and oversized try to step
                 * down the size
                 */
                spin_lock_bh(&ioat->ring_lock);
                active = ioat2_ring_active(ioat);
                if (active == 0 && ioat->alloc_order > ioat_get_alloc_order())
                        reshape_ring(ioat, ioat->alloc_order-1);
                spin_unlock_bh(&ioat->ring_lock);

                /* keep shrinking until we get back to our minimum
                 * default size
                 */
                if (ioat->alloc_order > ioat_get_alloc_order())
                        mod_timer(&chan->timer, jiffies + IDLE_TIMEOUT);
        }
        spin_unlock_bh(&chan->cleanup_lock);
}

static enum dma_status
ioat3_is_complete(struct dma_chan *c, dma_cookie_t cookie,
                  dma_cookie_t *done, dma_cookie_t *used)
{
        struct ioat2_dma_chan *ioat = to_ioat2_chan(c);

        if (ioat_is_complete(c, cookie, done, used) == DMA_SUCCESS)
                return DMA_SUCCESS;

        ioat3_cleanup(ioat);

        return ioat_is_complete(c, cookie, done, used);
}

static struct dma_async_tx_descriptor *
ioat3_prep_memset_lock(struct dma_chan *c, dma_addr_t dest, int value,
                       size_t len, unsigned long flags)
{
        struct ioat2_dma_chan *ioat = to_ioat2_chan(c);
        struct ioat_ring_ent *desc;
        size_t total_len = len;
        struct ioat_fill_descriptor *fill;
        int num_descs;
        u64 src_data = (0x0101010101010101ULL) * (value & 0xff);
        u16 idx;
        int i;

        num_descs = ioat2_xferlen_to_descs(ioat, len);
        if (likely(num_descs) &&
            ioat2_alloc_and_lock(&idx, ioat, num_descs) == 0)
                /* pass */;
        else
                return NULL;
        i = 0;
        do {
                size_t xfer_size = min_t(size_t, len, 1 << ioat->xfercap_log);

                desc = ioat2_get_ring_ent(ioat, idx + i);
                fill = desc->fill;

                fill->size = xfer_size;
                fill->src_data = src_data;
                fill->dst_addr = dest;
                fill->ctl = 0;
                fill->ctl_f.op = IOAT_OP_FILL;

                len -= xfer_size;
                dest += xfer_size;
                dump_desc_dbg(ioat, desc);
        } while (++i < num_descs);

        desc->txd.flags = flags;
        desc->len = total_len;
        fill->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
        fill->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
        fill->ctl_f.compl_write = 1;
        dump_desc_dbg(ioat, desc);

        /* we leave the channel locked to ensure in order submission */
        return &desc->txd;
}

static struct dma_async_tx_descriptor *
__ioat3_prep_xor_lock(struct dma_chan *c, enum sum_check_flags *result,
                      dma_addr_t dest, dma_addr_t *src, unsigned int src_cnt,
                      size_t len, unsigned long flags)
{
        struct ioat2_dma_chan *ioat = to_ioat2_chan(c);
        struct ioat_ring_ent *compl_desc;
        struct ioat_ring_ent *desc;
        struct ioat_ring_ent *ext;
        size_t total_len = len;
        struct ioat_xor_descriptor *xor;
        struct ioat_xor_ext_descriptor *xor_ex = NULL;
        struct ioat_dma_descriptor *hw;
        u32 offset = 0;
        int num_descs;
        int with_ext;
        int i;
        u16 idx;
        u8 op = result ? IOAT_OP_XOR_VAL : IOAT_OP_XOR;

        BUG_ON(src_cnt < 2);

        num_descs = ioat2_xferlen_to_descs(ioat, len);
        /* we need 2x the number of descriptors to cover greater than 5
         * sources
         */
        if (src_cnt > 5) {
                with_ext = 1;
                num_descs *= 2;
        } else
                with_ext = 0;

        /* completion writes from the raid engine may pass completion
         * writes from the legacy engine, so we need one extra null
         * (legacy) descriptor to ensure all completion writes arrive in
         * order.
         */
        if (likely(num_descs) &&
            ioat2_alloc_and_lock(&idx, ioat, num_descs+1) == 0)
                /* pass */;
        else
                return NULL;
        i = 0;
        do {
                struct ioat_raw_descriptor *descs[2];
                size_t xfer_size = min_t(size_t, len, 1 << ioat->xfercap_log);
                int s;

                desc = ioat2_get_ring_ent(ioat, idx + i);
                xor = desc->xor;

                /* save a branch by unconditionally retrieving the
                 * extended descriptor xor_set_src() knows to not write
                 * to it in the single descriptor case
                 */
                ext = ioat2_get_ring_ent(ioat, idx + i + 1);
                xor_ex = ext->xor_ex;

                descs[0] = (struct ioat_raw_descriptor *) xor;
                descs[1] = (struct ioat_raw_descriptor *) xor_ex;
                for (s = 0; s < src_cnt; s++)
                        xor_set_src(descs, src[s], offset, s);
                xor->size = xfer_size;
                xor->dst_addr = dest + offset;
                xor->ctl = 0;
                xor->ctl_f.op = op;
                xor->ctl_f.src_cnt = src_cnt_to_hw(src_cnt);

                len -= xfer_size;
                offset += xfer_size;
                dump_desc_dbg(ioat, desc);
        } while ((i += 1 + with_ext) < num_descs);

        /* last xor descriptor carries the unmap parameters and fence bit */
        desc->txd.flags = flags;
        desc->len = total_len;
        if (result)
                desc->result = result;
        xor->ctl_f.fence = !!(flags & DMA_PREP_FENCE);

        /* completion descriptor carries interrupt bit */
        compl_desc = ioat2_get_ring_ent(ioat, idx + i);
        compl_desc->txd.flags = flags & DMA_PREP_INTERRUPT;
        hw = compl_desc->hw;
        hw->ctl = 0;
        hw->ctl_f.null = 1;
        hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
        hw->ctl_f.compl_write = 1;
        hw->size = NULL_DESC_BUFFER_SIZE;
        dump_desc_dbg(ioat, compl_desc);

        /* we leave the channel locked to ensure in order submission */
        return &compl_desc->txd;
}

static struct dma_async_tx_descriptor *
ioat3_prep_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
               unsigned int src_cnt, size_t len, unsigned long flags)
{
        return __ioat3_prep_xor_lock(chan, NULL, dest, src, src_cnt, len, flags);
}

struct dma_async_tx_descriptor *
ioat3_prep_xor_val(struct dma_chan *chan, dma_addr_t *src,
                    unsigned int src_cnt, size_t len,
                    enum sum_check_flags *result, unsigned long flags)
{
        /* the cleanup routine only sets bits on validate failure, it
         * does not clear bits on validate success... so clear it here
         */
        *result = 0;

        return __ioat3_prep_xor_lock(chan, result, src[0], &src[1],
                                     src_cnt - 1, len, flags);
}

static void
dump_pq_desc_dbg(struct ioat2_dma_chan *ioat, struct ioat_ring_ent *desc, struct ioat_ring_ent *ext)
{
        struct device *dev = to_dev(&ioat->base);
        struct ioat_pq_descriptor *pq = desc->pq;
        struct ioat_pq_ext_descriptor *pq_ex = ext ? ext->pq_ex : NULL;
        struct ioat_raw_descriptor *descs[] = { (void *) pq, (void *) pq_ex };
        int src_cnt = src_cnt_to_sw(pq->ctl_f.src_cnt);
        int i;

        dev_dbg(dev, "desc[%d]: (%#llx->%#llx) flags: %#x"
                " sz: %#x ctl: %#x (op: %d int: %d compl: %d pq: '%s%s' src_cnt: %d)\n",
                desc_id(desc), (unsigned long long) desc->txd.phys,
                (unsigned long long) (pq_ex ? pq_ex->next : pq->next),
                desc->txd.flags, pq->size, pq->ctl, pq->ctl_f.op, pq->ctl_f.int_en,
                pq->ctl_f.compl_write,
                pq->ctl_f.p_disable ? "" : "p", pq->ctl_f.q_disable ? "" : "q",
                pq->ctl_f.src_cnt);
        for (i = 0; i < src_cnt; i++)
                dev_dbg(dev, "\tsrc[%d]: %#llx coef: %#x\n", i,
                        (unsigned long long) pq_get_src(descs, i), pq->coef[i]);
        dev_dbg(dev, "\tP: %#llx\n", pq->p_addr);
        dev_dbg(dev, "\tQ: %#llx\n", pq->q_addr);
}

static struct dma_async_tx_descriptor *
__ioat3_prep_pq_lock(struct dma_chan *c, enum sum_check_flags *result,
                     const dma_addr_t *dst, const dma_addr_t *src,
                     unsigned int src_cnt, const unsigned char *scf,
                     size_t len, unsigned long flags)
{
        struct ioat2_dma_chan *ioat = to_ioat2_chan(c);
        struct ioat_chan_common *chan = &ioat->base;
        struct ioat_ring_ent *compl_desc;
        struct ioat_ring_ent *desc;
        struct ioat_ring_ent *ext;
        size_t total_len = len;
        struct ioat_pq_descriptor *pq;
        struct ioat_pq_ext_descriptor *pq_ex = NULL;
        struct ioat_dma_descriptor *hw;
        u32 offset = 0;
        int num_descs;
        int with_ext;
        int i, s;
        u16 idx;
        u8 op = result ? IOAT_OP_PQ_VAL : IOAT_OP_PQ;

        dev_dbg(to_dev(chan), "%s\n", __func__);
        /* the engine requires at least two sources (we provide
         * at least 1 implied source in the DMA_PREP_CONTINUE case)
         */
        BUG_ON(src_cnt + dmaf_continue(flags) < 2);

        num_descs = ioat2_xferlen_to_descs(ioat, len);
        /* we need 2x the number of descriptors to cover greater than 3
         * sources (we need 1 extra source in the q-only continuation
         * case and 3 extra sources in the p+q continuation case.
         */
        if (src_cnt + dmaf_p_disabled_continue(flags) > 3 ||
            (dmaf_continue(flags) && !dmaf_p_disabled_continue(flags))) {
                with_ext = 1;
                num_descs *= 2;
        } else
                with_ext = 0;

        /* completion writes from the raid engine may pass completion
         * writes from the legacy engine, so we need one extra null
         * (legacy) descriptor to ensure all completion writes arrive in
         * order.
         */
        if (likely(num_descs) &&
            ioat2_alloc_and_lock(&idx, ioat, num_descs+1) == 0)
                /* pass */;
        else
                return NULL;
        i = 0;
        do {
                struct ioat_raw_descriptor *descs[2];
                size_t xfer_size = min_t(size_t, len, 1 << ioat->xfercap_log);

                desc = ioat2_get_ring_ent(ioat, idx + i);
                pq = desc->pq;

                /* save a branch by unconditionally retrieving the
                 * extended descriptor pq_set_src() knows to not write
                 * to it in the single descriptor case
                 */
                ext = ioat2_get_ring_ent(ioat, idx + i + with_ext);
                pq_ex = ext->pq_ex;

                descs[0] = (struct ioat_raw_descriptor *) pq;
                descs[1] = (struct ioat_raw_descriptor *) pq_ex;

                for (s = 0; s < src_cnt; s++)
                        pq_set_src(descs, src[s], offset, scf[s], s);

                /* see the comment for dma_maxpq in include/linux/dmaengine.h */
                if (dmaf_p_disabled_continue(flags))
                        pq_set_src(descs, dst[1], offset, 1, s++);
                else if (dmaf_continue(flags)) {
                        pq_set_src(descs, dst[0], offset, 0, s++);
                        pq_set_src(descs, dst[1], offset, 1, s++);
                        pq_set_src(descs, dst[1], offset, 0, s++);
                }
                pq->size = xfer_size;
                pq->p_addr = dst[0] + offset;
                pq->q_addr = dst[1] + offset;
                pq->ctl = 0;
                pq->ctl_f.op = op;
                pq->ctl_f.src_cnt = src_cnt_to_hw(s);
                pq->ctl_f.p_disable = !!(flags & DMA_PREP_PQ_DISABLE_P);
                pq->ctl_f.q_disable = !!(flags & DMA_PREP_PQ_DISABLE_Q);

                len -= xfer_size;
                offset += xfer_size;
        } while ((i += 1 + with_ext) < num_descs);

        /* last pq descriptor carries the unmap parameters and fence bit */
        desc->txd.flags = flags;
        desc->len = total_len;
        if (result)
                desc->result = result;
        pq->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
        dump_pq_desc_dbg(ioat, desc, ext);

        /* completion descriptor carries interrupt bit */
        compl_desc = ioat2_get_ring_ent(ioat, idx + i);
        compl_desc->txd.flags = flags & DMA_PREP_INTERRUPT;
        hw = compl_desc->hw;
        hw->ctl = 0;
        hw->ctl_f.null = 1;
        hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
        hw->ctl_f.compl_write = 1;
        hw->size = NULL_DESC_BUFFER_SIZE;
        dump_desc_dbg(ioat, compl_desc);

        /* we leave the channel locked to ensure in order submission */
        return &compl_desc->txd;
}

static struct dma_async_tx_descriptor *
ioat3_prep_pq(struct dma_chan *chan, dma_addr_t *dst, dma_addr_t *src,
              unsigned int src_cnt, const unsigned char *scf, size_t len,
              unsigned long flags)
{
        /* specify valid address for disabled result */
        if (flags & DMA_PREP_PQ_DISABLE_P)
                dst[0] = dst[1];
        if (flags & DMA_PREP_PQ_DISABLE_Q)
                dst[1] = dst[0];

        /* handle the single source multiply case from the raid6
         * recovery path
         */
        if ((flags & DMA_PREP_PQ_DISABLE_P) && src_cnt == 1) {
                dma_addr_t single_source[2];
                unsigned char single_source_coef[2];

                BUG_ON(flags & DMA_PREP_PQ_DISABLE_Q);
                single_source[0] = src[0];
                single_source[1] = src[0];
                single_source_coef[0] = scf[0];
                single_source_coef[1] = 0;

                return __ioat3_prep_pq_lock(chan, NULL, dst, single_source, 2,
                                            single_source_coef, len, flags);
        } else
                return __ioat3_prep_pq_lock(chan, NULL, dst, src, src_cnt, scf,
                                            len, flags);
}

struct dma_async_tx_descriptor *
ioat3_prep_pq_val(struct dma_chan *chan, dma_addr_t *pq, dma_addr_t *src,
                  unsigned int src_cnt, const unsigned char *scf, size_t len,
                  enum sum_check_flags *pqres, unsigned long flags)
{
        /* specify valid address for disabled result */
        if (flags & DMA_PREP_PQ_DISABLE_P)
                pq[0] = pq[1];
        if (flags & DMA_PREP_PQ_DISABLE_Q)
                pq[1] = pq[0];

        /* the cleanup routine only sets bits on validate failure, it
         * does not clear bits on validate success... so clear it here
         */
        *pqres = 0;

        return __ioat3_prep_pq_lock(chan, pqres, pq, src, src_cnt, scf, len,
                                    flags);
}

static struct dma_async_tx_descriptor *
ioat3_prep_pqxor(struct dma_chan *chan, dma_addr_t dst, dma_addr_t *src,
                 unsigned int src_cnt, size_t len, unsigned long flags)
{
        unsigned char scf[src_cnt];
        dma_addr_t pq[2];

        memset(scf, 0, src_cnt);
        pq[0] = dst;
        flags |= DMA_PREP_PQ_DISABLE_Q;
        pq[1] = dst; /* specify valid address for disabled result */

        return __ioat3_prep_pq_lock(chan, NULL, pq, src, src_cnt, scf, len,
                                    flags);
}

struct dma_async_tx_descriptor *
ioat3_prep_pqxor_val(struct dma_chan *chan, dma_addr_t *src,
                     unsigned int src_cnt, size_t len,
                     enum sum_check_flags *result, unsigned long flags)
{
        unsigned char scf[src_cnt];
        dma_addr_t pq[2];

        /* the cleanup routine only sets bits on validate failure, it
         * does not clear bits on validate success... so clear it here
         */
        *result = 0;

        memset(scf, 0, src_cnt);
        pq[0] = src[0];
        flags |= DMA_PREP_PQ_DISABLE_Q;
        pq[1] = pq[0]; /* specify valid address for disabled result */

        return __ioat3_prep_pq_lock(chan, result, pq, &src[1], src_cnt - 1, scf,
                                    len, flags);
}

static struct dma_async_tx_descriptor *
ioat3_prep_interrupt_lock(struct dma_chan *c, unsigned long flags)
{
        struct ioat2_dma_chan *ioat = to_ioat2_chan(c);
        struct ioat_ring_ent *desc;
        struct ioat_dma_descriptor *hw;
        u16 idx;

        if (ioat2_alloc_and_lock(&idx, ioat, 1) == 0)
                desc = ioat2_get_ring_ent(ioat, idx);
        else
                return NULL;

        hw = desc->hw;
        hw->ctl = 0;
        hw->ctl_f.null = 1;
        hw->ctl_f.int_en = 1;
        hw->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
        hw->ctl_f.compl_write = 1;
        hw->size = NULL_DESC_BUFFER_SIZE;
        hw->src_addr = 0;
        hw->dst_addr = 0;

        desc->txd.flags = flags;
        desc->len = 1;

        dump_desc_dbg(ioat, desc);

        /* we leave the channel locked to ensure in order submission */
        return &desc->txd;
}

static void __devinit ioat3_dma_test_callback(void *dma_async_param)
{
        struct completion *cmp = dma_async_param;

        complete(cmp);
}

#define IOAT_NUM_SRC_TEST 6 /* must be <= 8 */
static int __devinit ioat_xor_val_self_test(struct ioatdma_device *device)
{
        int i, src_idx;
        struct page *dest;
        struct page *xor_srcs[IOAT_NUM_SRC_TEST];
        struct page *xor_val_srcs[IOAT_NUM_SRC_TEST + 1];
        dma_addr_t dma_srcs[IOAT_NUM_SRC_TEST + 1];
        dma_addr_t dma_addr, dest_dma;
        struct dma_async_tx_descriptor *tx;
        struct dma_chan *dma_chan;
        dma_cookie_t cookie;
        u8 cmp_byte = 0;
        u32 cmp_word;
        u32 xor_val_result;
        int err = 0;
        struct completion cmp;
        unsigned long tmo;
        struct device *dev = &device->pdev->dev;
        struct dma_device *dma = &device->common;

        dev_dbg(dev, "%s\n", __func__);

        if (!dma_has_cap(DMA_XOR, dma->cap_mask))
                return 0;

        for (src_idx = 0; src_idx < IOAT_NUM_SRC_TEST; src_idx++) {
                xor_srcs[src_idx] = alloc_page(GFP_KERNEL);
                if (!xor_srcs[src_idx]) {
                        while (src_idx--)
                                __free_page(xor_srcs[src_idx]);
                        return -ENOMEM;
                }
        }

        dest = alloc_page(GFP_KERNEL);
        if (!dest) {
                while (src_idx--)
                        __free_page(xor_srcs[src_idx]);
                return -ENOMEM;
        }

        /* Fill in src buffers */
        for (src_idx = 0; src_idx < IOAT_NUM_SRC_TEST; src_idx++) {
                u8 *ptr = page_address(xor_srcs[src_idx]);
                for (i = 0; i < PAGE_SIZE; i++)
                        ptr[i] = (1 << src_idx);
        }

        for (src_idx = 0; src_idx < IOAT_NUM_SRC_TEST; src_idx++)
                cmp_byte ^= (u8) (1 << src_idx);

        cmp_word = (cmp_byte << 24) | (cmp_byte << 16) |
                        (cmp_byte << 8) | cmp_byte;

        memset(page_address(dest), 0, PAGE_SIZE);

        dma_chan = container_of(dma->channels.next, struct dma_chan,
                                device_node);
        if (dma->device_alloc_chan_resources(dma_chan) < 1) {
                err = -ENODEV;
                goto out;
        }

        /* test xor */
        dest_dma = dma_map_page(dev, dest, 0, PAGE_SIZE, DMA_FROM_DEVICE);
        for (i = 0; i < IOAT_NUM_SRC_TEST; i++)
                dma_srcs[i] = dma_map_page(dev, xor_srcs[i], 0, PAGE_SIZE,
                                           DMA_TO_DEVICE);
        tx = dma->device_prep_dma_xor(dma_chan, dest_dma, dma_srcs,
                                      IOAT_NUM_SRC_TEST, PAGE_SIZE,
                                      DMA_PREP_INTERRUPT);

        if (!tx) {
                dev_err(dev, "Self-test xor prep failed\n");
                err = -ENODEV;
                goto free_resources;
        }

        async_tx_ack(tx);
        init_completion(&cmp);
        tx->callback = ioat3_dma_test_callback;
        tx->callback_param = &cmp;
        cookie = tx->tx_submit(tx);
        if (cookie < 0) {
                dev_err(dev, "Self-test xor setup failed\n");
                err = -ENODEV;
                goto free_resources;
        }
        dma->device_issue_pending(dma_chan);

        tmo = wait_for_completion_timeout(&cmp, msecs_to_jiffies(3000));

        if (dma->device_is_tx_complete(dma_chan, cookie, NULL, NULL) != DMA_SUCCESS) {
                dev_err(dev, "Self-test xor timed out\n");
                err = -ENODEV;
                goto free_resources;
        }

        dma_sync_single_for_cpu(dev, dest_dma, PAGE_SIZE, DMA_FROM_DEVICE);
        for (i = 0; i < (PAGE_SIZE / sizeof(u32)); i++) {
                u32 *ptr = page_address(dest);
                if (ptr[i] != cmp_word) {
                        dev_err(dev, "Self-test xor failed compare\n");
                        err = -ENODEV;
                        goto free_resources;
                }
        }
        dma_sync_single_for_device(dev, dest_dma, PAGE_SIZE, DMA_TO_DEVICE);

        /* skip validate if the capability is not present */
        if (!dma_has_cap(DMA_XOR_VAL, dma_chan->device->cap_mask))
                goto free_resources;

        /* validate the sources with the destintation page */
        for (i = 0; i < IOAT_NUM_SRC_TEST; i++)
                xor_val_srcs[i] = xor_srcs[i];
        xor_val_srcs[i] = dest;

        xor_val_result = 1;

        for (i = 0; i < IOAT_NUM_SRC_TEST + 1; i++)
                dma_srcs[i] = dma_map_page(dev, xor_val_srcs[i], 0, PAGE_SIZE,
                                           DMA_TO_DEVICE);
        tx = dma->device_prep_dma_xor_val(dma_chan, dma_srcs,
                                          IOAT_NUM_SRC_TEST + 1, PAGE_SIZE,
                                          &xor_val_result, DMA_PREP_INTERRUPT);
        if (!tx) {
                dev_err(dev, "Self-test zero prep failed\n");
                err = -ENODEV;
                goto free_resources;
        }

        async_tx_ack(tx);
        init_completion(&cmp);
        tx->callback = ioat3_dma_test_callback;
        tx->callback_param = &cmp;
        cookie = tx->tx_submit(tx);
        if (cookie < 0) {
                dev_err(dev, "Self-test zero setup failed\n");
                err = -ENODEV;
                goto free_resources;
        }
        dma->device_issue_pending(dma_chan);

        tmo = wait_for_completion_timeout(&cmp, msecs_to_jiffies(3000));

        if (dma->device_is_tx_complete(dma_chan, cookie, NULL, NULL) != DMA_SUCCESS) {
                dev_err(dev, "Self-test validate timed out\n");
                err = -ENODEV;
                goto free_resources;
        }

        if (xor_val_result != 0) {
                dev_err(dev, "Self-test validate failed compare\n");
                err = -ENODEV;
                goto free_resources;
        }

        /* skip memset if the capability is not present */
        if (!dma_has_cap(DMA_MEMSET, dma_chan->device->cap_mask))
                goto free_resources;

        /* test memset */
        dma_addr = dma_map_page(dev, dest, 0,
                        PAGE_SIZE, DMA_FROM_DEVICE);
        tx = dma->device_prep_dma_memset(dma_chan, dma_addr, 0, PAGE_SIZE,
                                         DMA_PREP_INTERRUPT);
        if (!tx) {
                dev_err(dev, "Self-test memset prep failed\n");
                err = -ENODEV;
                goto free_resources;
        }

        async_tx_ack(tx);
        init_completion(&cmp);
        tx->callback = ioat3_dma_test_callback;
        tx->callback_param = &cmp;
        cookie = tx->tx_submit(tx);
        if (cookie < 0) {
                dev_err(dev, "Self-test memset setup failed\n");
                err = -ENODEV;
                goto free_resources;
        }
        dma->device_issue_pending(dma_chan);

        tmo = wait_for_completion_timeout(&cmp, msecs_to_jiffies(3000));

        if (dma->device_is_tx_complete(dma_chan, cookie, NULL, NULL) != DMA_SUCCESS) {
                dev_err(dev, "Self-test memset timed out\n");
                err = -ENODEV;
                goto free_resources;
        }

        for (i = 0; i < PAGE_SIZE/sizeof(u32); i++) {
                u32 *ptr = page_address(dest);
                if (ptr[i]) {
                        dev_err(dev, "Self-test memset failed compare\n");
                        err = -ENODEV;
                        goto free_resources;
                }
        }

        /* test for non-zero parity sum */
        xor_val_result = 0;
        for (i = 0; i < IOAT_NUM_SRC_TEST + 1; i++)
                dma_srcs[i] = dma_map_page(dev, xor_val_srcs[i], 0, PAGE_SIZE,
                                           DMA_TO_DEVICE);
        tx = dma->device_prep_dma_xor_val(dma_chan, dma_srcs,
                                          IOAT_NUM_SRC_TEST + 1, PAGE_SIZE,
                                          &xor_val_result, DMA_PREP_INTERRUPT);
        if (!tx) {
                dev_err(dev, "Self-test 2nd zero prep failed\n");
                err = -ENODEV;
                goto free_resources;
        }

        async_tx_ack(tx);
        init_completion(&cmp);
        tx->callback = ioat3_dma_test_callback;
        tx->callback_param = &cmp;
        cookie = tx->tx_submit(tx);
        if (cookie < 0) {
                dev_err(dev, "Self-test  2nd zero setup failed\n");
                err = -ENODEV;
                goto free_resources;
        }
        dma->device_issue_pending(dma_chan);

        tmo = wait_for_completion_timeout(&cmp, msecs_to_jiffies(3000));

        if (dma->device_is_tx_complete(dma_chan, cookie, NULL, NULL) != DMA_SUCCESS) {
                dev_err(dev, "Self-test 2nd validate timed out\n");
                err = -ENODEV;
                goto free_resources;
        }

        if (xor_val_result != SUM_CHECK_P_RESULT) {
                dev_err(dev, "Self-test validate failed compare\n");
                err = -ENODEV;
                goto free_resources;
        }

free_resources:
        dma->device_free_chan_resources(dma_chan);
out:
        src_idx = IOAT_NUM_SRC_TEST;
        while (src_idx--)
                __free_page(xor_srcs[src_idx]);
        __free_page(dest);
        return err;
}

static int __devinit ioat3_dma_self_test(struct ioatdma_device *device)
{
        int rc = ioat_dma_self_test(device);

        if (rc)
                return rc;

        rc = ioat_xor_val_self_test(device);
        if (rc)
                return rc;

        return 0;
}

static int ioat3_reset_hw(struct ioat_chan_common *chan)
{
        /* throw away whatever the channel was doing and get it
         * initialized, with ioat3 specific workarounds
         */
        struct ioatdma_device *device = chan->device;
        struct pci_dev *pdev = device->pdev;
        u32 chanerr;
        u16 dev_id;
        int err;

        ioat2_quiesce(chan, msecs_to_jiffies(100));

        chanerr = readl(chan->reg_base + IOAT_CHANERR_OFFSET);
        writel(chanerr, chan->reg_base + IOAT_CHANERR_OFFSET);

        /* -= IOAT ver.3 workarounds =- */
        /* Write CHANERRMSK_INT with 3E07h to mask out the errors
         * that can cause stability issues for IOAT ver.3, and clear any
         * pending errors
         */
        pci_write_config_dword(pdev, IOAT_PCI_CHANERRMASK_INT_OFFSET, 0x3e07);
        err = pci_read_config_dword(pdev, IOAT_PCI_CHANERR_INT_OFFSET, &chanerr);
        if (err) {
                dev_err(&pdev->dev, "channel error register unreachable\n");
                return err;
        }
        pci_write_config_dword(pdev, IOAT_PCI_CHANERR_INT_OFFSET, chanerr);

        /* Clear DMAUNCERRSTS Cfg-Reg Parity Error status bit
         * (workaround for spurious config parity error after restart)
         */
        pci_read_config_word(pdev, IOAT_PCI_DEVICE_ID_OFFSET, &dev_id);
        if (dev_id == PCI_DEVICE_ID_INTEL_IOAT_TBG0)
                pci_write_config_dword(pdev, IOAT_PCI_DMAUNCERRSTS_OFFSET, 0x10);

        return ioat2_reset_sync(chan, msecs_to_jiffies(200));
}

int __devinit ioat3_dma_probe(struct ioatdma_device *device, int dca)
{
        struct pci_dev *pdev = device->pdev;
        int dca_en = system_has_dca_enabled(pdev);
        struct dma_device *dma;
        struct dma_chan *c;
        struct ioat_chan_common *chan;
        bool is_raid_device = false;
        int err;
        u32 cap;

        device->enumerate_channels = ioat2_enumerate_channels;
        device->reset_hw = ioat3_reset_hw;
        device->self_test = ioat3_dma_self_test;
        dma = &device->common;
        dma->device_prep_dma_memcpy = ioat2_dma_prep_memcpy_lock;
        dma->device_issue_pending = ioat2_issue_pending;
        dma->device_alloc_chan_resources = ioat2_alloc_chan_resources;
        dma->device_free_chan_resources = ioat2_free_chan_resources;

        dma_cap_set(DMA_INTERRUPT, dma->cap_mask);
        dma->device_prep_dma_interrupt = ioat3_prep_interrupt_lock;

        cap = readl(device->reg_base + IOAT_DMA_CAP_OFFSET);

        /* dca is incompatible with raid operations */
        if (dca_en && (cap & (IOAT_CAP_XOR|IOAT_CAP_PQ)))
                cap &= ~(IOAT_CAP_XOR|IOAT_CAP_PQ);

        if (cap & IOAT_CAP_XOR) {
                is_raid_device = true;
                dma->max_xor = 8;
                dma->xor_align = 2;

                dma_cap_set(DMA_XOR, dma->cap_mask);
                dma->device_prep_dma_xor = ioat3_prep_xor;

                dma_cap_set(DMA_XOR_VAL, dma->cap_mask);
                dma->device_prep_dma_xor_val = ioat3_prep_xor_val;
        }
        if (cap & IOAT_CAP_PQ) {
                is_raid_device = true;
                dma_set_maxpq(dma, 8, 0);
                dma->pq_align = 2;

                dma_cap_set(DMA_PQ, dma->cap_mask);
                dma->device_prep_dma_pq = ioat3_prep_pq;

                dma_cap_set(DMA_PQ_VAL, dma->cap_mask);
                dma->device_prep_dma_pq_val = ioat3_prep_pq_val;

                if (!(cap & IOAT_CAP_XOR)) {
                        dma->max_xor = 8;
                        dma->xor_align = 2;

                        dma_cap_set(DMA_XOR, dma->cap_mask);
                        dma->device_prep_dma_xor = ioat3_prep_pqxor;

                        dma_cap_set(DMA_XOR_VAL, dma->cap_mask);
                        dma->device_prep_dma_xor_val = ioat3_prep_pqxor_val;
                }
        }
        if (is_raid_device && (cap & IOAT_CAP_FILL_BLOCK)) {
                dma_cap_set(DMA_MEMSET, dma->cap_mask);
                dma->device_prep_dma_memset = ioat3_prep_memset_lock;
        }


        if (is_raid_device) {
                dma->device_is_tx_complete = ioat3_is_complete;
                device->cleanup_tasklet = ioat3_cleanup_tasklet;
                device->timer_fn = ioat3_timer_event;
        } else {
                dma->device_is_tx_complete = ioat2_is_complete;
                device->cleanup_tasklet = ioat2_cleanup_tasklet;
                device->timer_fn = ioat2_timer_event;
        }

        #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
        dma_cap_clear(DMA_PQ_VAL, dma->cap_mask);
        dma->device_prep_dma_pq_val = NULL;
        #endif

        #ifdef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
        dma_cap_clear(DMA_XOR_VAL, dma->cap_mask);
        dma->device_prep_dma_xor_val = NULL;
        #endif

        err = ioat_probe(device);
        if (err)
                return err;
        ioat_set_tcp_copy_break(262144);

        list_for_each_entry(c, &dma->channels, device_node) {
                chan = to_chan_common(c);
                writel(IOAT_DMA_DCA_ANY_CPU,
                       chan->reg_base + IOAT_DCACTRL_OFFSET);
        }

        err = ioat_register(device);
        if (err)
                return err;

        ioat_kobject_add(device, &ioat2_ktype);

        if (dca)
                device->dca = ioat3_dca_init(pdev, device->reg_base);

        return 0;
}