[I/OAT]: Driver for the Intel(R) I/OAT DMA engine

Adds a new ioatdma driver

Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 839 insertions, 0 deletions

diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c
new file mode 100644
index 000000000000..11d48b97b36e
--- /dev/null
+++ b/drivers/dma/ioatdma.c
@@ -0,0 +1,839 @@
+/*
+ * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The full GNU General Public License is included in this distribution in the
+ * file called COPYING.
+ */
+
+/*
+ * This driver supports an Intel I/OAT DMA engine, which does asynchronous
+ * copy operations.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/dmaengine.h>
+#include <linux/delay.h>
+#include "ioatdma.h"
+#include "ioatdma_io.h"
+#include "ioatdma_registers.h"
+#include "ioatdma_hw.h"
+
+#define to_ioat_chan(chan) container_of(chan, struct ioat_dma_chan, common)
+#define to_ioat_device(dev) container_of(dev, struct ioat_device, common)
+#define to_ioat_desc(lh) container_of(lh, struct ioat_desc_sw, node)
+
+/* internal functions */
+static int __devinit ioat_probe(struct pci_dev *pdev, const struct pci_device_id *ent);
+static void __devexit ioat_remove(struct pci_dev *pdev);
+
+static int enumerate_dma_channels(struct ioat_device *device)
+{
+        u8 xfercap_scale;
+        u32 xfercap;
+        int i;
+        struct ioat_dma_chan *ioat_chan;
+
+        device->common.chancnt = ioatdma_read8(device, IOAT_CHANCNT_OFFSET);
+        xfercap_scale = ioatdma_read8(device, IOAT_XFERCAP_OFFSET);
+        xfercap = (xfercap_scale == 0 ? -1 : (1UL << xfercap_scale));
+
+        for (i = 0; i < device->common.chancnt; i++) {
+                ioat_chan = kzalloc(sizeof(*ioat_chan), GFP_KERNEL);
+                if (!ioat_chan) {
+                        device->common.chancnt = i;
+                        break;
+                }
+
+                ioat_chan->device = device;
+                ioat_chan->reg_base = device->reg_base + (0x80 * (i + 1));
+                ioat_chan->xfercap = xfercap;
+                spin_lock_init(&ioat_chan->cleanup_lock);
+                spin_lock_init(&ioat_chan->desc_lock);
+                INIT_LIST_HEAD(&ioat_chan->free_desc);
+                INIT_LIST_HEAD(&ioat_chan->used_desc);
+                /* This should be made common somewhere in dmaengine.c */
+                ioat_chan->common.device = &device->common;
+                ioat_chan->common.client = NULL;
+                list_add_tail(&ioat_chan->common.device_node,
+                              &device->common.channels);
+        }
+        return device->common.chancnt;
+}
+
+static struct ioat_desc_sw *ioat_dma_alloc_descriptor(
+        struct ioat_dma_chan *ioat_chan,
+        int flags)
+{
+        struct ioat_dma_descriptor *desc;
+        struct ioat_desc_sw *desc_sw;
+        struct ioat_device *ioat_device;
+        dma_addr_t phys;
+
+        ioat_device = to_ioat_device(ioat_chan->common.device);
+        desc = pci_pool_alloc(ioat_device->dma_pool, flags, &phys);
+        if (unlikely(!desc))
+                return NULL;
+
+        desc_sw = kzalloc(sizeof(*desc_sw), flags);
+        if (unlikely(!desc_sw)) {
+                pci_pool_free(ioat_device->dma_pool, desc, phys);
+                return NULL;
+        }
+
+        memset(desc, 0, sizeof(*desc));
+        desc_sw->hw = desc;
+        desc_sw->phys = phys;
+
+        return desc_sw;
+}
+
+#define INITIAL_IOAT_DESC_COUNT 128
+
+static void ioat_start_null_desc(struct ioat_dma_chan *ioat_chan);
+
+/* returns the actual number of allocated descriptors */
+static int ioat_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(chan);
+        struct ioat_desc_sw *desc = NULL;
+        u16 chanctrl;
+        u32 chanerr;
+        int i;
+        LIST_HEAD(tmp_list);
+
+        /*
+         * In-use bit automatically set by reading chanctrl
+         * If 0, we got it, if 1, someone else did
+         */
+        chanctrl = ioatdma_chan_read16(ioat_chan, IOAT_CHANCTRL_OFFSET);
+        if (chanctrl & IOAT_CHANCTRL_CHANNEL_IN_USE)
+                return -EBUSY;
+
+        /* Setup register to interrupt and write completion status on error */
+        chanctrl = IOAT_CHANCTRL_CHANNEL_IN_USE |
+                IOAT_CHANCTRL_ERR_INT_EN |
+                IOAT_CHANCTRL_ANY_ERR_ABORT_EN |
+                IOAT_CHANCTRL_ERR_COMPLETION_EN;
+        ioatdma_chan_write16(ioat_chan, IOAT_CHANCTRL_OFFSET, chanctrl);
+
+        chanerr = ioatdma_chan_read32(ioat_chan, IOAT_CHANERR_OFFSET);
+        if (chanerr) {
+                printk("IOAT: CHANERR = %x, clearing\n", chanerr);
+                ioatdma_chan_write32(ioat_chan, IOAT_CHANERR_OFFSET, chanerr);
+        }
+
+        /* Allocate descriptors */
+        for (i = 0; i < INITIAL_IOAT_DESC_COUNT; i++) {
+                desc = ioat_dma_alloc_descriptor(ioat_chan, GFP_KERNEL);
+                if (!desc) {
+                        printk(KERN_ERR "IOAT: Only %d initial descriptors\n", i);
+                        break;
+                }
+                list_add_tail(&desc->node, &tmp_list);
+        }
+        spin_lock_bh(&ioat_chan->desc_lock);
+        list_splice(&tmp_list, &ioat_chan->free_desc);
+        spin_unlock_bh(&ioat_chan->desc_lock);
+
+        /* allocate a completion writeback area */
+        /* doing 2 32bit writes to mmio since 1 64b write doesn't work */
+        ioat_chan->completion_virt =
+                pci_pool_alloc(ioat_chan->device->completion_pool,
+                               GFP_KERNEL,
+                               &ioat_chan->completion_addr);
+        memset(ioat_chan->completion_virt, 0,
+               sizeof(*ioat_chan->completion_virt));
+        ioatdma_chan_write32(ioat_chan, IOAT_CHANCMP_OFFSET_LOW,
+                       ((u64) ioat_chan->completion_addr) & 0x00000000FFFFFFFF);
+        ioatdma_chan_write32(ioat_chan, IOAT_CHANCMP_OFFSET_HIGH,
+                       ((u64) ioat_chan->completion_addr) >> 32);
+
+        ioat_start_null_desc(ioat_chan);
+        return i;
+}
+
+static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *ioat_chan);
+
+static void ioat_dma_free_chan_resources(struct dma_chan *chan)
+{
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(chan);
+        struct ioat_device *ioat_device = to_ioat_device(chan->device);
+        struct ioat_desc_sw *desc, *_desc;
+        u16 chanctrl;
+        int in_use_descs = 0;
+
+        ioat_dma_memcpy_cleanup(ioat_chan);
+
+        ioatdma_chan_write8(ioat_chan, IOAT_CHANCMD_OFFSET, IOAT_CHANCMD_RESET);
+
+        spin_lock_bh(&ioat_chan->desc_lock);
+        list_for_each_entry_safe(desc, _desc, &ioat_chan->used_desc, node) {
+                in_use_descs++;
+                list_del(&desc->node);
+                pci_pool_free(ioat_device->dma_pool, desc->hw, desc->phys);
+                kfree(desc);
+        }
+        list_for_each_entry_safe(desc, _desc, &ioat_chan->free_desc, node) {
+                list_del(&desc->node);
+                pci_pool_free(ioat_device->dma_pool, desc->hw, desc->phys);
+                kfree(desc);
+        }
+        spin_unlock_bh(&ioat_chan->desc_lock);
+
+        pci_pool_free(ioat_device->completion_pool,
+                      ioat_chan->completion_virt,
+                      ioat_chan->completion_addr);
+
+        /* one is ok since we left it on there on purpose */
+        if (in_use_descs > 1)
+                printk(KERN_ERR "IOAT: Freeing %d in use descriptors!\n",
+                        in_use_descs - 1);
+
+        ioat_chan->last_completion = ioat_chan->completion_addr = 0;
+
+        /* Tell hw the chan is free */
+        chanctrl = ioatdma_chan_read16(ioat_chan, IOAT_CHANCTRL_OFFSET);
+        chanctrl &= ~IOAT_CHANCTRL_CHANNEL_IN_USE;
+        ioatdma_chan_write16(ioat_chan, IOAT_CHANCTRL_OFFSET, chanctrl);
+}
+
+/**
+ * do_ioat_dma_memcpy - actual function that initiates a IOAT DMA transaction
+ * @chan: IOAT DMA channel handle
+ * @dest: DMA destination address
+ * @src: DMA source address
+ * @len: transaction length in bytes
+ */
+
+static dma_cookie_t do_ioat_dma_memcpy(struct ioat_dma_chan *ioat_chan,
+                                       dma_addr_t dest,
+                                       dma_addr_t src,
+                                       size_t len)
+{
+        struct ioat_desc_sw *first;
+        struct ioat_desc_sw *prev;
+        struct ioat_desc_sw *new;
+        dma_cookie_t cookie;
+        LIST_HEAD(new_chain);
+        u32 copy;
+        size_t orig_len;
+        dma_addr_t orig_src, orig_dst;
+        unsigned int desc_count = 0;
+        unsigned int append = 0;
+
+        if (!ioat_chan || !dest || !src)
+                return -EFAULT;
+
+        if (!len)
+                return ioat_chan->common.cookie;
+
+        orig_len = len;
+        orig_src = src;
+        orig_dst = dest;
+
+        first = NULL;
+        prev = NULL;
+
+        spin_lock_bh(&ioat_chan->desc_lock);
+
+        while (len) {
+                if (!list_empty(&ioat_chan->free_desc)) {
+                        new = to_ioat_desc(ioat_chan->free_desc.next);
+                        list_del(&new->node);
+                } else {
+                        /* try to get another desc */
+                        new = ioat_dma_alloc_descriptor(ioat_chan, GFP_ATOMIC);
+                        /* will this ever happen? */
+                        /* TODO add upper limit on these */
+                        BUG_ON(!new);
+                }
+
+                copy = min((u32) len, ioat_chan->xfercap);
+
+                new->hw->size = copy;
+                new->hw->ctl = 0;
+                new->hw->src_addr = src;
+                new->hw->dst_addr = dest;
+                new->cookie = 0;
+
+                /* chain together the physical address list for the HW */
+                if (!first)
+                        first = new;
+                else
+                        prev->hw->next = (u64) new->phys;
+
+                prev = new;
+
+                len  -= copy;
+                dest += copy;
+                src  += copy;
+
+                list_add_tail(&new->node, &new_chain);
+                desc_count++;
+        }
+        new->hw->ctl = IOAT_DMA_DESCRIPTOR_CTL_CP_STS;
+        new->hw->next = 0;
+
+        /* cookie incr and addition to used_list must be atomic */
+
+        cookie = ioat_chan->common.cookie;
+        cookie++;
+        if (cookie < 0)
+                cookie = 1;
+        ioat_chan->common.cookie = new->cookie = cookie;
+
+        pci_unmap_addr_set(new, src, orig_src);
+        pci_unmap_addr_set(new, dst, orig_dst);
+        pci_unmap_len_set(new, src_len, orig_len);
+        pci_unmap_len_set(new, dst_len, orig_len);
+
+        /* write address into NextDescriptor field of last desc in chain */
+        to_ioat_desc(ioat_chan->used_desc.prev)->hw->next = first->phys;
+        list_splice_init(&new_chain, ioat_chan->used_desc.prev);
+
+        ioat_chan->pending += desc_count;
+        if (ioat_chan->pending >= 20) {
+                append = 1;
+                ioat_chan->pending = 0;
+        }
+
+        spin_unlock_bh(&ioat_chan->desc_lock);
+
+        if (append)
+                ioatdma_chan_write8(ioat_chan,
+                                    IOAT_CHANCMD_OFFSET,
+                                    IOAT_CHANCMD_APPEND);
+        return cookie;
+}
+
+/**
+ * ioat_dma_memcpy_buf_to_buf - wrapper that takes src & dest bufs
+ * @chan: IOAT DMA channel handle
+ * @dest: DMA destination address
+ * @src: DMA source address
+ * @len: transaction length in bytes
+ */
+
+static dma_cookie_t ioat_dma_memcpy_buf_to_buf(struct dma_chan *chan,
+                                               void *dest,
+                                               void *src,
+                                               size_t len)
+{
+        dma_addr_t dest_addr;
+        dma_addr_t src_addr;
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(chan);
+
+        dest_addr = pci_map_single(ioat_chan->device->pdev,
+                dest, len, PCI_DMA_FROMDEVICE);
+        src_addr = pci_map_single(ioat_chan->device->pdev,
+                src, len, PCI_DMA_TODEVICE);
+
+        return do_ioat_dma_memcpy(ioat_chan, dest_addr, src_addr, len);
+}
+
+/**
+ * ioat_dma_memcpy_buf_to_pg - wrapper, copying from a buf to a page
+ * @chan: IOAT DMA channel handle
+ * @page: pointer to the page to copy to
+ * @offset: offset into that page
+ * @src: DMA source address
+ * @len: transaction length in bytes
+ */
+
+static dma_cookie_t ioat_dma_memcpy_buf_to_pg(struct dma_chan *chan,
+                                              struct page *page,
+                                              unsigned int offset,
+                                              void *src,
+                                              size_t len)
+{
+        dma_addr_t dest_addr;
+        dma_addr_t src_addr;
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(chan);
+
+        dest_addr = pci_map_page(ioat_chan->device->pdev,
+                page, offset, len, PCI_DMA_FROMDEVICE);
+        src_addr = pci_map_single(ioat_chan->device->pdev,
+                src, len, PCI_DMA_TODEVICE);
+
+        return do_ioat_dma_memcpy(ioat_chan, dest_addr, src_addr, len);
+}
+
+/**
+ * ioat_dma_memcpy_pg_to_pg - wrapper, copying between two pages
+ * @chan: IOAT DMA channel handle
+ * @dest_pg: pointer to the page to copy to
+ * @dest_off: offset into that page
+ * @src_pg: pointer to the page to copy from
+ * @src_off: offset into that page
+ * @len: transaction length in bytes. This is guaranteed to not make a copy
+ *       across a page boundary.
+ */
+
+static dma_cookie_t ioat_dma_memcpy_pg_to_pg(struct dma_chan *chan,
+                                             struct page *dest_pg,
+                                             unsigned int dest_off,
+                                             struct page *src_pg,
+                                             unsigned int src_off,
+                                             size_t len)
+{
+        dma_addr_t dest_addr;
+        dma_addr_t src_addr;
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(chan);
+
+        dest_addr = pci_map_page(ioat_chan->device->pdev,
+                dest_pg, dest_off, len, PCI_DMA_FROMDEVICE);
+        src_addr = pci_map_page(ioat_chan->device->pdev,
+                src_pg, src_off, len, PCI_DMA_TODEVICE);
+
+        return do_ioat_dma_memcpy(ioat_chan, dest_addr, src_addr, len);
+}
+
+/**
+ * ioat_dma_memcpy_issue_pending - push potentially unrecognoized appended descriptors to hw
+ * @chan: DMA channel handle
+ */
+
+static void ioat_dma_memcpy_issue_pending(struct dma_chan *chan)
+{
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(chan);
+
+        if (ioat_chan->pending != 0) {
+                ioat_chan->pending = 0;
+                ioatdma_chan_write8(ioat_chan,
+                                    IOAT_CHANCMD_OFFSET,
+                                    IOAT_CHANCMD_APPEND);
+        }
+}
+
+static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *chan)
+{
+        unsigned long phys_complete;
+        struct ioat_desc_sw *desc, *_desc;
+        dma_cookie_t cookie = 0;
+
+        prefetch(chan->completion_virt);
+
+        if (!spin_trylock(&chan->cleanup_lock))
+                return;
+
+        /* The completion writeback can happen at any time,
+           so reads by the driver need to be atomic operations
+           The descriptor physical addresses are limited to 32-bits
+           when the CPU can only do a 32-bit mov */
+
+#if (BITS_PER_LONG == 64)
+        phys_complete =
+        chan->completion_virt->full & IOAT_CHANSTS_COMPLETED_DESCRIPTOR_ADDR;
+#else
+        phys_complete = chan->completion_virt->low & IOAT_LOW_COMPLETION_MASK;
+#endif
+
+        if ((chan->completion_virt->full & IOAT_CHANSTS_DMA_TRANSFER_STATUS) ==
+                IOAT_CHANSTS_DMA_TRANSFER_STATUS_HALTED) {
+                printk("IOAT: Channel halted, chanerr = %x\n",
+                        ioatdma_chan_read32(chan, IOAT_CHANERR_OFFSET));
+
+                /* TODO do something to salvage the situation */
+        }
+
+        if (phys_complete == chan->last_completion) {
+                spin_unlock(&chan->cleanup_lock);
+                return;
+        }
+
+        spin_lock_bh(&chan->desc_lock);
+        list_for_each_entry_safe(desc, _desc, &chan->used_desc, node) {
+
+                /*
+                 * Incoming DMA requests may use multiple descriptors, due to
+                 * exceeding xfercap, perhaps. If so, only the last one will
+                 * have a cookie, and require unmapping.
+                 */
+                if (desc->cookie) {
+                        cookie = desc->cookie;
+
+                        /* yes we are unmapping both _page and _single alloc'd
+                           regions with unmap_page. Is this *really* that bad?
+                        */
+                        pci_unmap_page(chan->device->pdev,
+                                        pci_unmap_addr(desc, dst),
+                                        pci_unmap_len(desc, dst_len),
+                                        PCI_DMA_FROMDEVICE);
+                        pci_unmap_page(chan->device->pdev,
+                                        pci_unmap_addr(desc, src),
+                                        pci_unmap_len(desc, src_len),
+                                        PCI_DMA_TODEVICE);
+                }
+
+                if (desc->phys != phys_complete) {
+                        /* a completed entry, but not the last, so cleanup */
+                        list_del(&desc->node);
+                        list_add_tail(&desc->node, &chan->free_desc);
+                } else {
+                        /* last used desc. Do not remove, so we can append from
+                           it, but don't look at it next time, either */
+                        desc->cookie = 0;
+
+                        /* TODO check status bits? */
+                        break;
+                }
+        }
+
+        spin_unlock_bh(&chan->desc_lock);
+
+        chan->last_completion = phys_complete;
+        if (cookie != 0)
+                chan->completed_cookie = cookie;
+
+        spin_unlock(&chan->cleanup_lock);
+}
+
+/**
+ * ioat_dma_is_complete - poll the status of a IOAT DMA transaction
+ * @chan: IOAT DMA channel handle
+ * @cookie: DMA transaction identifier
+ */
+
+static enum dma_status ioat_dma_is_complete(struct dma_chan *chan,
+                                            dma_cookie_t cookie,
+                                            dma_cookie_t *done,
+                                            dma_cookie_t *used)
+{
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(chan);
+        dma_cookie_t last_used;
+        dma_cookie_t last_complete;
+        enum dma_status ret;
+
+        last_used = chan->cookie;
+        last_complete = ioat_chan->completed_cookie;
+
+        if (done)
+                *done= last_complete;
+        if (used)
+                *used = last_used;
+
+        ret = dma_async_is_complete(cookie, last_complete, last_used);
+        if (ret == DMA_SUCCESS)
+                return ret;
+
+        ioat_dma_memcpy_cleanup(ioat_chan);
+
+        last_used = chan->cookie;
+        last_complete = ioat_chan->completed_cookie;
+
+        if (done)
+                *done= last_complete;
+        if (used)
+                *used = last_used;
+
+        return dma_async_is_complete(cookie, last_complete, last_used);
+}
+
+/* PCI API */
+
+static struct pci_device_id ioat_pci_tbl[] = {
+        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT) },
+        { 0, }
+};
+
+static struct pci_driver ioat_pci_drv = {
+        .name   = "ioatdma",
+        .id_table = ioat_pci_tbl,
+        .probe  = ioat_probe,
+        .remove = __devexit_p(ioat_remove),
+};
+
+static irqreturn_t ioat_do_interrupt(int irq, void *data, struct pt_regs *regs)
+{
+        struct ioat_device *instance = data;
+        unsigned long attnstatus;
+        u8 intrctrl;
+
+        intrctrl = ioatdma_read8(instance, IOAT_INTRCTRL_OFFSET);
+
+        if (!(intrctrl & IOAT_INTRCTRL_MASTER_INT_EN))
+                return IRQ_NONE;
+
+        if (!(intrctrl & IOAT_INTRCTRL_INT_STATUS)) {
+                ioatdma_write8(instance, IOAT_INTRCTRL_OFFSET, intrctrl);
+                return IRQ_NONE;
+        }
+
+        attnstatus = ioatdma_read32(instance, IOAT_ATTNSTATUS_OFFSET);
+
+        printk(KERN_ERR "ioatdma error: interrupt! status %lx\n", attnstatus);
+
+        ioatdma_write8(instance, IOAT_INTRCTRL_OFFSET, intrctrl);
+        return IRQ_HANDLED;
+}
+
+static void ioat_start_null_desc(struct ioat_dma_chan *ioat_chan)
+{
+        struct ioat_desc_sw *desc;
+
+        spin_lock_bh(&ioat_chan->desc_lock);
+
+        if (!list_empty(&ioat_chan->free_desc)) {
+                desc = to_ioat_desc(ioat_chan->free_desc.next);
+                list_del(&desc->node);
+        } else {
+                /* try to get another desc */
+                spin_unlock_bh(&ioat_chan->desc_lock);
+                desc = ioat_dma_alloc_descriptor(ioat_chan, GFP_KERNEL);
+                spin_lock_bh(&ioat_chan->desc_lock);
+                /* will this ever happen? */
+                BUG_ON(!desc);
+        }
+
+        desc->hw->ctl = IOAT_DMA_DESCRIPTOR_NUL;
+        desc->hw->next = 0;
+
+        list_add_tail(&desc->node, &ioat_chan->used_desc);
+        spin_unlock_bh(&ioat_chan->desc_lock);
+
+#if (BITS_PER_LONG == 64)
+        ioatdma_chan_write64(ioat_chan, IOAT_CHAINADDR_OFFSET, desc->phys);
+#else
+        ioatdma_chan_write32(ioat_chan,
+                             IOAT_CHAINADDR_OFFSET_LOW,
+                             (u32) desc->phys);
+        ioatdma_chan_write32(ioat_chan, IOAT_CHAINADDR_OFFSET_HIGH, 0);
+#endif
+        ioatdma_chan_write8(ioat_chan, IOAT_CHANCMD_OFFSET, IOAT_CHANCMD_START);
+}
+
+/*
+ * Perform a IOAT transaction to verify the HW works.
+ */
+#define IOAT_TEST_SIZE 2000
+
+static int ioat_self_test(struct ioat_device *device)
+{
+        int i;
+        u8 *src;
+        u8 *dest;
+        struct dma_chan *dma_chan;
+        dma_cookie_t cookie;
+        int err = 0;
+
+        src = kzalloc(sizeof(u8) * IOAT_TEST_SIZE, SLAB_KERNEL);
+        if (!src)
+                return -ENOMEM;
+        dest = kzalloc(sizeof(u8) * IOAT_TEST_SIZE, SLAB_KERNEL);
+        if (!dest) {
+                kfree(src);
+                return -ENOMEM;
+        }
+
+        /* Fill in src buffer */
+        for (i = 0; i < IOAT_TEST_SIZE; i++)
+                src[i] = (u8)i;
+
+        /* Start copy, using first DMA channel */
+        dma_chan = container_of(device->common.channels.next,
+                                struct dma_chan,
+                                device_node);
+        if (ioat_dma_alloc_chan_resources(dma_chan) < 1) {
+                err = -ENODEV;
+                goto out;
+        }
+
+        cookie = ioat_dma_memcpy_buf_to_buf(dma_chan, dest, src, IOAT_TEST_SIZE);
+        ioat_dma_memcpy_issue_pending(dma_chan);
+        msleep(1);
+
+        if (ioat_dma_is_complete(dma_chan, cookie, NULL, NULL) != DMA_SUCCESS) {
+                printk(KERN_ERR "ioatdma: Self-test copy timed out, disabling\n");
+                err = -ENODEV;
+                goto free_resources;
+        }
+        if (memcmp(src, dest, IOAT_TEST_SIZE)) {
+                printk(KERN_ERR "ioatdma: Self-test copy failed compare, disabling\n");
+                err = -ENODEV;
+                goto free_resources;
+        }
+
+free_resources:
+        ioat_dma_free_chan_resources(dma_chan);
+out:
+        kfree(src);
+        kfree(dest);
+        return err;
+}
+
+static int __devinit ioat_probe(struct pci_dev *pdev,
+                                const struct pci_device_id *ent)
+{
+        int err;
+        unsigned long mmio_start, mmio_len;
+        void *reg_base;
+        struct ioat_device *device;
+
+        err = pci_enable_device(pdev);
+        if (err)
+                goto err_enable_device;
+
+        err = pci_set_dma_mask(pdev, DMA_64BIT_MASK);
+        if (err)
+                err = pci_set_dma_mask(pdev, DMA_32BIT_MASK);
+        if (err)
+                goto err_set_dma_mask;
+
+        err = pci_request_regions(pdev, ioat_pci_drv.name);
+        if (err)
+                goto err_request_regions;
+
+        mmio_start = pci_resource_start(pdev, 0);
+        mmio_len = pci_resource_len(pdev, 0);
+
+        reg_base = ioremap(mmio_start, mmio_len);
+        if (!reg_base) {
+                err = -ENOMEM;
+                goto err_ioremap;
+        }
+
+        device = kzalloc(sizeof(*device), GFP_KERNEL);
+        if (!device) {
+                err = -ENOMEM;
+                goto err_kzalloc;
+        }
+
+        /* DMA coherent memory pool for DMA descriptor allocations */
+        device->dma_pool = pci_pool_create("dma_desc_pool", pdev,
+                sizeof(struct ioat_dma_descriptor), 64, 0);
+        if (!device->dma_pool) {
+                err = -ENOMEM;
+                goto err_dma_pool;
+        }
+
+        device->completion_pool = pci_pool_create("completion_pool", pdev, sizeof(u64), SMP_CACHE_BYTES, SMP_CACHE_BYTES);
+        if (!device->completion_pool) {
+                err = -ENOMEM;
+                goto err_completion_pool;
+        }
+
+        device->pdev = pdev;
+        pci_set_drvdata(pdev, device);
+#ifdef CONFIG_PCI_MSI
+        if (pci_enable_msi(pdev) == 0) {
+                device->msi = 1;
+        } else {
+                device->msi = 0;
+        }
+#endif
+        err = request_irq(pdev->irq, &ioat_do_interrupt, SA_SHIRQ, "ioat",
+                device);
+        if (err)
+                goto err_irq;
+
+        device->reg_base = reg_base;
+
+        ioatdma_write8(device, IOAT_INTRCTRL_OFFSET, IOAT_INTRCTRL_MASTER_INT_EN);
+        pci_set_master(pdev);
+
+        INIT_LIST_HEAD(&device->common.channels);
+        enumerate_dma_channels(device);
+
+        device->common.device_alloc_chan_resources = ioat_dma_alloc_chan_resources;
+        device->common.device_free_chan_resources = ioat_dma_free_chan_resources;
+        device->common.device_memcpy_buf_to_buf = ioat_dma_memcpy_buf_to_buf;
+        device->common.device_memcpy_buf_to_pg = ioat_dma_memcpy_buf_to_pg;
+        device->common.device_memcpy_pg_to_pg = ioat_dma_memcpy_pg_to_pg;
+        device->common.device_memcpy_complete = ioat_dma_is_complete;
+        device->common.device_memcpy_issue_pending = ioat_dma_memcpy_issue_pending;
+        printk(KERN_INFO "Intel(R) I/OAT DMA Engine found, %d channels\n",
+                device->common.chancnt);
+
+        err = ioat_self_test(device);
+        if (err)
+                goto err_self_test;
+
+        dma_async_device_register(&device->common);
+
+        return 0;
+
+err_self_test:
+err_irq:
+        pci_pool_destroy(device->completion_pool);
+err_completion_pool:
+        pci_pool_destroy(device->dma_pool);
+err_dma_pool:
+        kfree(device);
+err_kzalloc:
+        iounmap(reg_base);
+err_ioremap:
+        pci_release_regions(pdev);
+err_request_regions:
+err_set_dma_mask:
+        pci_disable_device(pdev);
+err_enable_device:
+        return err;
+}
+
+static void __devexit ioat_remove(struct pci_dev *pdev)
+{
+        struct ioat_device *device;
+        struct dma_chan *chan, *_chan;
+        struct ioat_dma_chan *ioat_chan;
+
+        device = pci_get_drvdata(pdev);
+        dma_async_device_unregister(&device->common);
+
+        free_irq(device->pdev->irq, device);
+#ifdef CONFIG_PCI_MSI
+        if (device->msi)
+                pci_disable_msi(device->pdev);
+#endif
+        pci_pool_destroy(device->dma_pool);
+        pci_pool_destroy(device->completion_pool);
+        iounmap(device->reg_base);
+        pci_release_regions(pdev);
+        pci_disable_device(pdev);
+        list_for_each_entry_safe(chan, _chan, &device->common.channels, device_node) {
+                ioat_chan = to_ioat_chan(chan);
+                list_del(&chan->device_node);
+                kfree(ioat_chan);
+        }
+        kfree(device);
+}
+
+/* MODULE API */
+MODULE_VERSION("1.7");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Intel Corporation");
+
+static int __init ioat_init_module(void)
+{
+        /* it's currently unsafe to unload this module */
+        /* if forced, worst case is that rmmod hangs */
+        if (THIS_MODULE != NULL)
+                THIS_MODULE->unsafe = 1;
+
+        return pci_module_init(&ioat_pci_drv);
+}
+
+module_init(ioat_init_module);
+
+static void __exit ioat_exit_module(void)
+{
+        pci_unregister_driver(&ioat_pci_drv);
+}
+
+module_exit(ioat_exit_module);