dmaengine: refactor dmaengine around dma_async_tx_descriptor

The current dmaengine interface defines mutliple routines per operation,
i.e. dma_async_memcpy_buf_to_buf, dma_async_memcpy_buf_to_page etc.  Adding
more operation types (xor, crc, etc) to this model would result in an
unmanageable number of method permutations.

	Are we really going to add a set of hooks for each DMA engine
	whizbang feature?
		- Jeff Garzik

The descriptor creation process is refactored using the new common
dma_async_tx_descriptor structure.  Instead of per driver
do_<operation>_<dest>_to_<src> methods, drivers integrate
dma_async_tx_descriptor into their private software descriptor and then
define a 'prep' routine per operation.  The prep routine allocates a
descriptor and ensures that the tx_set_src, tx_set_dest, tx_submit routines
are valid.  Descriptor creation and submission becomes:

struct dma_device *dev;
struct dma_chan *chan;
struct dma_async_tx_descriptor *tx;

tx = dev->device_prep_dma_<operation>(chan, len, int_flag)
tx->tx_set_src(dma_addr_t, tx, index /* for multi-source ops */)
tx->tx_set_dest(dma_addr_t, tx, index)
tx->tx_submit(tx)

In addition to the refactoring, dma_async_tx_descriptor also lays the
groundwork for definining cross-channel-operation dependencies, and a
callback facility for asynchronous notification of operation completion.

Changelog:
* drop dma mapping methods, suggested by Chris Leech
* fix ioat_dma_dependency_added, also caught by Andrew Morton
* fix dma_sync_wait, change from Andrew Morton
* uninline large functions, change from Andrew Morton
* add tx->callback = NULL to dmaengine calls to interoperate with async_tx
  calls
* hookup ioat_tx_submit
* convert channel capabilities to a 'cpumask_t like' bitmap
* removed DMA_TX_ARRAY_INIT, no longer needed
* checkpatch.pl fixes
* make set_src, set_dest, and tx_submit descriptor specific methods
* fixup git-ioat merge
* move group_list and phys to dma_async_tx_descriptor

Cc: Jeff Garzik <jeff@garzik.org>
Cc: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>

1 files changed, 137 insertions, 158 deletions

diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c
index c4209af4fde4..171044930282 100644
--- a/drivers/dma/ioatdma.c
+++ b/drivers/dma/ioatdma.c
@@ -38,6 +38,7 @@
 #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)
+#define tx_to_ioat_desc(tx) container_of(tx, struct ioat_desc_sw, async_tx)
 
 /* internal functions */
 static int __devinit ioat_probe(struct pci_dev *pdev, const struct pci_device_id *ent);
@@ -78,6 +79,73 @@ static int enumerate_dma_channels(struct ioat_device *device)
         return device->common.chancnt;
 }
 
+static void
+ioat_set_src(dma_addr_t addr, struct dma_async_tx_descriptor *tx, int index)
+{
+        struct ioat_desc_sw *iter, *desc = tx_to_ioat_desc(tx);
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(tx->chan);
+
+        pci_unmap_addr_set(desc, src, addr);
+
+        list_for_each_entry(iter, &desc->async_tx.tx_list, node) {
+                iter->hw->src_addr = addr;
+                addr += ioat_chan->xfercap;
+        }
+
+}
+
+static void
+ioat_set_dest(dma_addr_t addr, struct dma_async_tx_descriptor *tx, int index)
+{
+        struct ioat_desc_sw *iter, *desc = tx_to_ioat_desc(tx);
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(tx->chan);
+
+        pci_unmap_addr_set(desc, dst, addr);
+
+        list_for_each_entry(iter, &desc->async_tx.tx_list, node) {
+                iter->hw->dst_addr = addr;
+                addr += ioat_chan->xfercap;
+        }
+}
+
+static dma_cookie_t
+ioat_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(tx->chan);
+        struct ioat_desc_sw *desc = tx_to_ioat_desc(tx);
+        int append = 0;
+        dma_cookie_t cookie;
+        struct ioat_desc_sw *group_start;
+
+        group_start = list_entry(desc->async_tx.tx_list.next,
+                                 struct ioat_desc_sw, node);
+        spin_lock_bh(&ioat_chan->desc_lock);
+        /* 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 = desc->async_tx.cookie = cookie;
+
+        /* write address into NextDescriptor field of last desc in chain */
+        to_ioat_desc(ioat_chan->used_desc.prev)->hw->next =
+                                                group_start->async_tx.phys;
+        list_splice_init(&desc->async_tx.tx_list, ioat_chan->used_desc.prev);
+
+        ioat_chan->pending += desc->tx_cnt;
+        if (ioat_chan->pending >= 4) {
+                append = 1;
+                ioat_chan->pending = 0;
+        }
+        spin_unlock_bh(&ioat_chan->desc_lock);
+
+        if (append)
+                writeb(IOAT_CHANCMD_APPEND,
+                        ioat_chan->reg_base + IOAT_CHANCMD_OFFSET);
+        
+        return cookie;
+}
+
 static struct ioat_desc_sw *ioat_dma_alloc_descriptor(
         struct ioat_dma_chan *ioat_chan,
         gfp_t flags)
@@ -99,8 +167,13 @@ static struct ioat_desc_sw *ioat_dma_alloc_descriptor(
         }
 
         memset(desc, 0, sizeof(*desc));
+        dma_async_tx_descriptor_init(&desc_sw->async_tx, &ioat_chan->common);
+        desc_sw->async_tx.tx_set_src = ioat_set_src;
+        desc_sw->async_tx.tx_set_dest = ioat_set_dest;
+        desc_sw->async_tx.tx_submit = ioat_tx_submit;
+        INIT_LIST_HEAD(&desc_sw->async_tx.tx_list);
         desc_sw->hw = desc;
-        desc_sw->phys = phys;
+        desc_sw->async_tx.phys = phys;
 
         return desc_sw;
 }
@@ -188,12 +261,14 @@ static void ioat_dma_free_chan_resources(struct dma_chan *chan)
         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);
+                pci_pool_free(ioat_device->dma_pool, desc->hw,
+                              desc->async_tx.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);
+                pci_pool_free(ioat_device->dma_pool, desc->hw,
+                              desc->async_tx.phys);
                 kfree(desc);
         }
         spin_unlock_bh(&ioat_chan->desc_lock);
@@ -215,45 +290,25 @@ static void ioat_dma_free_chan_resources(struct dma_chan *chan)
         writew(chanctrl, ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
 }
 
-/**
- * do_ioat_dma_memcpy - actual function that initiates a IOAT DMA transaction
- * @ioat_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)
+static struct dma_async_tx_descriptor *
+ioat_dma_prep_memcpy(struct dma_chan *chan, size_t len, int int_en)
 {
-        struct ioat_desc_sw *first;
-        struct ioat_desc_sw *prev;
-        struct ioat_desc_sw *new;
-        dma_cookie_t cookie;
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(chan);
+        struct ioat_desc_sw *first, *prev, *new;
         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;
+        int desc_count = 0;
 
         if (!len)
-                return ioat_chan->common.cookie;
+                return NULL;
 
         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);
@@ -270,140 +325,36 @@ static dma_cookie_t do_ioat_dma_memcpy(struct ioat_dma_chan *ioat_chan,
 
                 new->hw->size = copy;
                 new->hw->ctl = 0;
-                new->hw->src_addr = src;
-                new->hw->dst_addr = dest;
-                new->cookie = 0;
+                new->async_tx.cookie = 0;
+                new->async_tx.ack = 1;
 
                 /* chain together the physical address list for the HW */
                 if (!first)
                         first = new;
                 else
-                        prev->hw->next = (u64) new->phys;
+                        prev->hw->next = (u64) new->async_tx.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 */
+        list_splice(&new_chain, &new->async_tx.tx_list);
 
-        cookie = ioat_chan->common.cookie;
-        cookie++;
-        if (cookie < 0)
-                cookie = 1;
-        ioat_chan->common.cookie = new->cookie = cookie;
+        new->hw->ctl = IOAT_DMA_DESCRIPTOR_CTL_CP_STS;
+        new->hw->next = 0;
+        new->tx_cnt = desc_count;
+        new->async_tx.ack = 0; /* client is in control of this ack */
+        new->async_tx.cookie = -EBUSY;
 
-        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 >= 4) {
-                append = 1;
-                ioat_chan->pending = 0;
-        }
-
         spin_unlock_bh(&ioat_chan->desc_lock);
 
-        if (append)
-                writeb(IOAT_CHANCMD_APPEND,
-                       ioat_chan->reg_base + IOAT_CHANCMD_OFFSET);
-        return cookie;
+        return new ? &new->async_tx : NULL;
 }
 
-/**
- * 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 not to 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 unrecognized appended descriptors to hw
@@ -465,8 +416,8 @@ static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *chan)
                  * exceeding xfercap, perhaps. If so, only the last one will
                  * have a cookie, and require unmapping.
                  */
-                if (desc->cookie) {
-                        cookie = desc->cookie;
+                if (desc->async_tx.cookie) {
+                        cookie = desc->async_tx.cookie;
 
                         /* yes we are unmapping both _page and _single alloc'd
                            regions with unmap_page. Is this *really* that bad?
@@ -481,14 +432,19 @@ static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *chan)
                                         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);
+                if (desc->async_tx.phys != phys_complete) {
+                        /* a completed entry, but not the last, so cleanup
+                         * if the client is done with the descriptor
+                         */
+                        if (desc->async_tx.ack) {
+                                list_del(&desc->node);
+                                list_add_tail(&desc->node, &chan->free_desc);
+                        } else
+                                desc->async_tx.cookie = 0;
                 } 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;
+                        desc->async_tx.cookie = 0;
 
                         /* TODO check status bits? */
                         break;
@@ -504,6 +460,17 @@ static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *chan)
         spin_unlock(&chan->cleanup_lock);
 }
 
+static void ioat_dma_dependency_added(struct dma_chan *chan)
+{
+        struct ioat_dma_chan *ioat_chan = to_ioat_chan(chan);
+        spin_lock_bh(&ioat_chan->desc_lock);
+        if (ioat_chan->pending == 0) {
+                spin_unlock_bh(&ioat_chan->desc_lock);
+                ioat_dma_memcpy_cleanup(ioat_chan);
+        } else
+                spin_unlock_bh(&ioat_chan->desc_lock);
+}
+
 /**
  * ioat_dma_is_complete - poll the status of a IOAT DMA transaction
  * @chan: IOAT DMA channel handle
@@ -606,13 +573,14 @@ static void ioat_start_null_desc(struct ioat_dma_chan *ioat_chan)
 
         desc->hw->ctl = IOAT_DMA_DESCRIPTOR_NUL;
         desc->hw->next = 0;
+        desc->async_tx.ack = 1;
 
         list_add_tail(&desc->node, &ioat_chan->used_desc);
         spin_unlock_bh(&ioat_chan->desc_lock);
 
-        writel(((u64) desc->phys) & 0x00000000FFFFFFFF,
+        writel(((u64) desc->async_tx.phys) & 0x00000000FFFFFFFF,
                ioat_chan->reg_base + IOAT_CHAINADDR_OFFSET_LOW);
-        writel(((u64) desc->phys) >> 32,
+        writel(((u64) desc->async_tx.phys) >> 32,
                ioat_chan->reg_base + IOAT_CHAINADDR_OFFSET_HIGH);
 
         writeb(IOAT_CHANCMD_START, ioat_chan->reg_base + IOAT_CHANCMD_OFFSET);
@@ -629,6 +597,8 @@ static int ioat_self_test(struct ioat_device *device)
         u8 *src;
         u8 *dest;
         struct dma_chan *dma_chan;
+        struct dma_async_tx_descriptor *tx;
+        dma_addr_t addr;
         dma_cookie_t cookie;
         int err = 0;
 
@@ -654,7 +624,15 @@ static int ioat_self_test(struct ioat_device *device)
                 goto out;
         }
 
-        cookie = ioat_dma_memcpy_buf_to_buf(dma_chan, dest, src, IOAT_TEST_SIZE);
+        tx = ioat_dma_prep_memcpy(dma_chan, IOAT_TEST_SIZE, 0);
+        async_tx_ack(tx);
+        addr = dma_map_single(dma_chan->device->dev, src, IOAT_TEST_SIZE,
+                        DMA_TO_DEVICE);
+        ioat_set_src(addr, tx, 0);
+        addr = dma_map_single(dma_chan->device->dev, dest, IOAT_TEST_SIZE,
+                        DMA_FROM_DEVICE);
+        ioat_set_dest(addr, tx, 0);
+        cookie = ioat_tx_submit(tx);
         ioat_dma_memcpy_issue_pending(dma_chan);
         msleep(1);
 
@@ -750,13 +728,14 @@ static int __devinit ioat_probe(struct pci_dev *pdev,
         INIT_LIST_HEAD(&device->common.channels);
         enumerate_dma_channels(device);
 
+        dma_cap_set(DMA_MEMCPY, device->common.cap_mask);
         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;
+        device->common.device_prep_dma_memcpy = ioat_dma_prep_memcpy;
+        device->common.device_is_tx_complete = ioat_dma_is_complete;
+        device->common.device_issue_pending = ioat_dma_memcpy_issue_pending;
+        device->common.device_dependency_added = ioat_dma_dependency_added;
+        device->common.dev = &pdev->dev;
         printk(KERN_INFO "Intel(R) I/OAT DMA Engine found, %d channels\n",
                 device->common.chancnt);