dmaengine: ioatdma: remove dma_v2.*
Clean out dma_v2 and remove ioat2 calls since we are moving everything
to just ioat.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 3cf2639..02b5c04 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -41,6 +41,19 @@
module_param(ioat_pending_level, int, 0644);
MODULE_PARM_DESC(ioat_pending_level,
"high-water mark for pushing ioat descriptors (default: 4)");
+int ioat_ring_alloc_order = 8;
+module_param(ioat_ring_alloc_order, int, 0644);
+MODULE_PARM_DESC(ioat_ring_alloc_order,
+ "ioat+: allocate 2^n descriptors per channel (default: 8 max: 16)");
+static int ioat_ring_max_alloc_order = IOAT_MAX_ORDER;
+module_param(ioat_ring_max_alloc_order, int, 0644);
+MODULE_PARM_DESC(ioat_ring_max_alloc_order,
+ "ioat+: upper limit for ring size (default: 16)");
+static char ioat_interrupt_style[32] = "msix";
+module_param_string(ioat_interrupt_style, ioat_interrupt_style,
+ sizeof(ioat_interrupt_style), 0644);
+MODULE_PARM_DESC(ioat_interrupt_style,
+ "set ioat interrupt style: msix (default), msi, intx");
/**
* ioat_dma_do_interrupt - handler used for single vector interrupt mode
@@ -314,12 +327,6 @@
return err;
}
-static char ioat_interrupt_style[32] = "msix";
-module_param_string(ioat_interrupt_style, ioat_interrupt_style,
- sizeof(ioat_interrupt_style), 0644);
-MODULE_PARM_DESC(ioat_interrupt_style,
- "set ioat interrupt style: msix (default), msi, intx");
-
/**
* ioat_dma_setup_interrupts - setup interrupt handler
* @ioat_dma: ioat dma device
@@ -577,3 +584,651 @@
INIT_LIST_HEAD(&dma->channels);
}
+
+void __ioat_issue_pending(struct ioatdma_chan *ioat_chan)
+{
+ ioat_chan->dmacount += ioat_ring_pending(ioat_chan);
+ ioat_chan->issued = ioat_chan->head;
+ writew(ioat_chan->dmacount,
+ ioat_chan->reg_base + IOAT_CHAN_DMACOUNT_OFFSET);
+ dev_dbg(to_dev(ioat_chan),
+ "%s: head: %#x tail: %#x issued: %#x count: %#x\n",
+ __func__, ioat_chan->head, ioat_chan->tail,
+ ioat_chan->issued, ioat_chan->dmacount);
+}
+
+void ioat_issue_pending(struct dma_chan *c)
+{
+ struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+
+ if (ioat_ring_pending(ioat_chan)) {
+ spin_lock_bh(&ioat_chan->prep_lock);
+ __ioat_issue_pending(ioat_chan);
+ spin_unlock_bh(&ioat_chan->prep_lock);
+ }
+}
+
+/**
+ * ioat_update_pending - log pending descriptors
+ * @ioat: ioat+ channel
+ *
+ * Check if the number of unsubmitted descriptors has exceeded the
+ * watermark. Called with prep_lock held
+ */
+static void ioat_update_pending(struct ioatdma_chan *ioat_chan)
+{
+ if (ioat_ring_pending(ioat_chan) > ioat_pending_level)
+ __ioat_issue_pending(ioat_chan);
+}
+
+static void __ioat_start_null_desc(struct ioatdma_chan *ioat_chan)
+{
+ struct ioat_ring_ent *desc;
+ struct ioat_dma_descriptor *hw;
+
+ if (ioat_ring_space(ioat_chan) < 1) {
+ dev_err(to_dev(ioat_chan),
+ "Unable to start null desc - ring full\n");
+ return;
+ }
+
+ dev_dbg(to_dev(ioat_chan),
+ "%s: head: %#x tail: %#x issued: %#x\n",
+ __func__, ioat_chan->head, ioat_chan->tail, ioat_chan->issued);
+ desc = ioat_get_ring_ent(ioat_chan, ioat_chan->head);
+
+ hw = desc->hw;
+ hw->ctl = 0;
+ hw->ctl_f.null = 1;
+ hw->ctl_f.int_en = 1;
+ hw->ctl_f.compl_write = 1;
+ /* set size to non-zero value (channel returns error when size is 0) */
+ hw->size = NULL_DESC_BUFFER_SIZE;
+ hw->src_addr = 0;
+ hw->dst_addr = 0;
+ async_tx_ack(&desc->txd);
+ ioat_set_chainaddr(ioat_chan, desc->txd.phys);
+ dump_desc_dbg(ioat_chan, desc);
+ /* make sure descriptors are written before we submit */
+ wmb();
+ ioat_chan->head += 1;
+ __ioat_issue_pending(ioat_chan);
+}
+
+static void ioat_start_null_desc(struct ioatdma_chan *ioat_chan)
+{
+ spin_lock_bh(&ioat_chan->prep_lock);
+ __ioat_start_null_desc(ioat_chan);
+ spin_unlock_bh(&ioat_chan->prep_lock);
+}
+
+void __ioat_restart_chan(struct ioatdma_chan *ioat_chan)
+{
+ /* set the tail to be re-issued */
+ ioat_chan->issued = ioat_chan->tail;
+ ioat_chan->dmacount = 0;
+ set_bit(IOAT_COMPLETION_PENDING, &ioat_chan->state);
+ mod_timer(&ioat_chan->timer, jiffies + COMPLETION_TIMEOUT);
+
+ dev_dbg(to_dev(ioat_chan),
+ "%s: head: %#x tail: %#x issued: %#x count: %#x\n",
+ __func__, ioat_chan->head, ioat_chan->tail,
+ ioat_chan->issued, ioat_chan->dmacount);
+
+ if (ioat_ring_pending(ioat_chan)) {
+ struct ioat_ring_ent *desc;
+
+ desc = ioat_get_ring_ent(ioat_chan, ioat_chan->tail);
+ ioat_set_chainaddr(ioat_chan, desc->txd.phys);
+ __ioat_issue_pending(ioat_chan);
+ } else
+ __ioat_start_null_desc(ioat_chan);
+}
+
+int ioat_quiesce(struct ioatdma_chan *ioat_chan, unsigned long tmo)
+{
+ unsigned long end = jiffies + tmo;
+ int err = 0;
+ u32 status;
+
+ status = ioat_chansts(ioat_chan);
+ if (is_ioat_active(status) || is_ioat_idle(status))
+ ioat_suspend(ioat_chan);
+ while (is_ioat_active(status) || is_ioat_idle(status)) {
+ if (tmo && time_after(jiffies, end)) {
+ err = -ETIMEDOUT;
+ break;
+ }
+ status = ioat_chansts(ioat_chan);
+ cpu_relax();
+ }
+
+ return err;
+}
+
+int ioat_reset_sync(struct ioatdma_chan *ioat_chan, unsigned long tmo)
+{
+ unsigned long end = jiffies + tmo;
+ int err = 0;
+
+ ioat_reset(ioat_chan);
+ while (ioat_reset_pending(ioat_chan)) {
+ if (end && time_after(jiffies, end)) {
+ err = -ETIMEDOUT;
+ break;
+ }
+ cpu_relax();
+ }
+
+ return err;
+}
+
+/**
+ * ioat_enumerate_channels - find and initialize the device's channels
+ * @ioat_dma: the ioat dma device to be enumerated
+ */
+int ioat_enumerate_channels(struct ioatdma_device *ioat_dma)
+{
+ struct ioatdma_chan *ioat_chan;
+ struct device *dev = &ioat_dma->pdev->dev;
+ struct dma_device *dma = &ioat_dma->dma_dev;
+ u8 xfercap_log;
+ int i;
+
+ INIT_LIST_HEAD(&dma->channels);
+ dma->chancnt = readb(ioat_dma->reg_base + IOAT_CHANCNT_OFFSET);
+ dma->chancnt &= 0x1f; /* bits [4:0] valid */
+ if (dma->chancnt > ARRAY_SIZE(ioat_dma->idx)) {
+ dev_warn(dev, "(%d) exceeds max supported channels (%zu)\n",
+ dma->chancnt, ARRAY_SIZE(ioat_dma->idx));
+ dma->chancnt = ARRAY_SIZE(ioat_dma->idx);
+ }
+ xfercap_log = readb(ioat_dma->reg_base + IOAT_XFERCAP_OFFSET);
+ xfercap_log &= 0x1f; /* bits [4:0] valid */
+ if (xfercap_log == 0)
+ return 0;
+ dev_dbg(dev, "%s: xfercap = %d\n", __func__, 1 << xfercap_log);
+
+ for (i = 0; i < dma->chancnt; i++) {
+ ioat_chan = devm_kzalloc(dev, sizeof(*ioat_chan), GFP_KERNEL);
+ if (!ioat_chan)
+ break;
+
+ ioat_init_channel(ioat_dma, ioat_chan, i);
+ ioat_chan->xfercap_log = xfercap_log;
+ spin_lock_init(&ioat_chan->prep_lock);
+ if (ioat_dma->reset_hw(ioat_chan)) {
+ i = 0;
+ break;
+ }
+ }
+ dma->chancnt = i;
+ return i;
+}
+
+static dma_cookie_t ioat_tx_submit_unlock(struct dma_async_tx_descriptor *tx)
+{
+ struct dma_chan *c = tx->chan;
+ struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+ dma_cookie_t cookie;
+
+ cookie = dma_cookie_assign(tx);
+ dev_dbg(to_dev(ioat_chan), "%s: cookie: %d\n", __func__, cookie);
+
+ if (!test_and_set_bit(IOAT_CHAN_ACTIVE, &ioat_chan->state))
+ mod_timer(&ioat_chan->timer, jiffies + COMPLETION_TIMEOUT);
+
+ /* make descriptor updates visible before advancing ioat->head,
+ * this is purposefully not smp_wmb() since we are also
+ * publishing the descriptor updates to a dma device
+ */
+ wmb();
+
+ ioat_chan->head += ioat_chan->produce;
+
+ ioat_update_pending(ioat_chan);
+ spin_unlock_bh(&ioat_chan->prep_lock);
+
+ return cookie;
+}
+
+static struct ioat_ring_ent *
+ioat_alloc_ring_ent(struct dma_chan *chan, gfp_t flags)
+{
+ struct ioat_dma_descriptor *hw;
+ struct ioat_ring_ent *desc;
+ struct ioatdma_device *ioat_dma;
+ dma_addr_t phys;
+
+ ioat_dma = to_ioatdma_device(chan->device);
+ hw = pci_pool_alloc(ioat_dma->dma_pool, flags, &phys);
+ if (!hw)
+ return NULL;
+ memset(hw, 0, sizeof(*hw));
+
+ desc = kmem_cache_zalloc(ioat_cache, flags);
+ if (!desc) {
+ pci_pool_free(ioat_dma->dma_pool, hw, phys);
+ return NULL;
+ }
+
+ dma_async_tx_descriptor_init(&desc->txd, chan);
+ desc->txd.tx_submit = ioat_tx_submit_unlock;
+ desc->hw = hw;
+ desc->txd.phys = phys;
+ return desc;
+}
+
+static void
+ioat_free_ring_ent(struct ioat_ring_ent *desc, struct dma_chan *chan)
+{
+ struct ioatdma_device *ioat_dma;
+
+ ioat_dma = to_ioatdma_device(chan->device);
+ pci_pool_free(ioat_dma->dma_pool, desc->hw, desc->txd.phys);
+ kmem_cache_free(ioat_cache, desc);
+}
+
+static struct ioat_ring_ent **
+ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags)
+{
+ struct ioat_ring_ent **ring;
+ int descs = 1 << order;
+ int i;
+
+ if (order > ioat_get_max_alloc_order())
+ return NULL;
+
+ /* allocate the array to hold the software ring */
+ ring = kcalloc(descs, sizeof(*ring), flags);
+ if (!ring)
+ return NULL;
+ for (i = 0; i < descs; i++) {
+ ring[i] = ioat_alloc_ring_ent(c, flags);
+ if (!ring[i]) {
+ while (i--)
+ ioat_free_ring_ent(ring[i], c);
+ kfree(ring);
+ return NULL;
+ }
+ set_desc_id(ring[i], i);
+ }
+
+ /* link descs */
+ for (i = 0; i < descs-1; i++) {
+ struct ioat_ring_ent *next = ring[i+1];
+ struct ioat_dma_descriptor *hw = ring[i]->hw;
+
+ hw->next = next->txd.phys;
+ }
+ ring[i]->hw->next = ring[0]->txd.phys;
+
+ return ring;
+}
+
+/**
+ * ioat_free_chan_resources - release all the descriptors
+ * @chan: the channel to be cleaned
+ */
+void ioat_free_chan_resources(struct dma_chan *c)
+{
+ struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+ struct ioatdma_device *ioat_dma = ioat_chan->ioat_dma;
+ struct ioat_ring_ent *desc;
+ const int total_descs = 1 << ioat_chan->alloc_order;
+ int descs;
+ int i;
+
+ /* Before freeing channel resources first check
+ * if they have been previously allocated for this channel.
+ */
+ if (!ioat_chan->ring)
+ return;
+
+ ioat_stop(ioat_chan);
+ ioat_dma->reset_hw(ioat_chan);
+
+ spin_lock_bh(&ioat_chan->cleanup_lock);
+ spin_lock_bh(&ioat_chan->prep_lock);
+ descs = ioat_ring_space(ioat_chan);
+ dev_dbg(to_dev(ioat_chan), "freeing %d idle descriptors\n", descs);
+ for (i = 0; i < descs; i++) {
+ desc = ioat_get_ring_ent(ioat_chan, ioat_chan->head + i);
+ ioat_free_ring_ent(desc, c);
+ }
+
+ if (descs < total_descs)
+ dev_err(to_dev(ioat_chan), "Freeing %d in use descriptors!\n",
+ total_descs - descs);
+
+ for (i = 0; i < total_descs - descs; i++) {
+ desc = ioat_get_ring_ent(ioat_chan, ioat_chan->tail + i);
+ dump_desc_dbg(ioat_chan, desc);
+ ioat_free_ring_ent(desc, c);
+ }
+
+ kfree(ioat_chan->ring);
+ ioat_chan->ring = NULL;
+ ioat_chan->alloc_order = 0;
+ pci_pool_free(ioat_dma->completion_pool, ioat_chan->completion,
+ ioat_chan->completion_dma);
+ spin_unlock_bh(&ioat_chan->prep_lock);
+ spin_unlock_bh(&ioat_chan->cleanup_lock);
+
+ ioat_chan->last_completion = 0;
+ ioat_chan->completion_dma = 0;
+ ioat_chan->dmacount = 0;
+}
+
+/* ioat_alloc_chan_resources - allocate/initialize ioat descriptor ring
+ * @chan: channel to be initialized
+ */
+int ioat_alloc_chan_resources(struct dma_chan *c)
+{
+ struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+ struct ioat_ring_ent **ring;
+ u64 status;
+ int order;
+ int i = 0;
+ u32 chanerr;
+
+ /* have we already been set up? */
+ if (ioat_chan->ring)
+ return 1 << ioat_chan->alloc_order;
+
+ /* Setup register to interrupt and write completion status on error */
+ writew(IOAT_CHANCTRL_RUN, ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
+
+ /* allocate a completion writeback area */
+ /* doing 2 32bit writes to mmio since 1 64b write doesn't work */
+ ioat_chan->completion =
+ pci_pool_alloc(ioat_chan->ioat_dma->completion_pool,
+ GFP_KERNEL, &ioat_chan->completion_dma);
+ if (!ioat_chan->completion)
+ return -ENOMEM;
+
+ memset(ioat_chan->completion, 0, sizeof(*ioat_chan->completion));
+ writel(((u64)ioat_chan->completion_dma) & 0x00000000FFFFFFFF,
+ ioat_chan->reg_base + IOAT_CHANCMP_OFFSET_LOW);
+ writel(((u64)ioat_chan->completion_dma) >> 32,
+ ioat_chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH);
+
+ order = ioat_get_alloc_order();
+ ring = ioat_alloc_ring(c, order, GFP_KERNEL);
+ if (!ring)
+ return -ENOMEM;
+
+ spin_lock_bh(&ioat_chan->cleanup_lock);
+ spin_lock_bh(&ioat_chan->prep_lock);
+ ioat_chan->ring = ring;
+ ioat_chan->head = 0;
+ ioat_chan->issued = 0;
+ ioat_chan->tail = 0;
+ ioat_chan->alloc_order = order;
+ set_bit(IOAT_RUN, &ioat_chan->state);
+ spin_unlock_bh(&ioat_chan->prep_lock);
+ spin_unlock_bh(&ioat_chan->cleanup_lock);
+
+ ioat_start_null_desc(ioat_chan);
+
+ /* check that we got off the ground */
+ do {
+ udelay(1);
+ status = ioat_chansts(ioat_chan);
+ } while (i++ < 20 && !is_ioat_active(status) && !is_ioat_idle(status));
+
+ if (is_ioat_active(status) || is_ioat_idle(status))
+ return 1 << ioat_chan->alloc_order;
+
+ chanerr = readl(ioat_chan->reg_base + IOAT_CHANERR_OFFSET);
+
+ dev_WARN(to_dev(ioat_chan),
+ "failed to start channel chanerr: %#x\n", chanerr);
+ ioat_free_chan_resources(c);
+ return -EFAULT;
+}
+
+bool reshape_ring(struct ioatdma_chan *ioat_chan, int order)
+{
+ /* reshape differs from normal ring allocation in that we want
+ * to allocate a new software ring while only
+ * extending/truncating the hardware ring
+ */
+ struct dma_chan *c = &ioat_chan->dma_chan;
+ const u32 curr_size = ioat_ring_size(ioat_chan);
+ const u16 active = ioat_ring_active(ioat_chan);
+ const u32 new_size = 1 << order;
+ struct ioat_ring_ent **ring;
+ u32 i;
+
+ if (order > ioat_get_max_alloc_order())
+ return false;
+
+ /* double check that we have at least 1 free descriptor */
+ if (active == curr_size)
+ return false;
+
+ /* when shrinking, verify that we can hold the current active
+ * set in the new ring
+ */
+ if (active >= new_size)
+ return false;
+
+ /* allocate the array to hold the software ring */
+ ring = kcalloc(new_size, sizeof(*ring), GFP_NOWAIT);
+ if (!ring)
+ return false;
+
+ /* allocate/trim descriptors as needed */
+ if (new_size > curr_size) {
+ /* copy current descriptors to the new ring */
+ for (i = 0; i < curr_size; i++) {
+ u16 curr_idx = (ioat_chan->tail+i) & (curr_size-1);
+ u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
+
+ ring[new_idx] = ioat_chan->ring[curr_idx];
+ set_desc_id(ring[new_idx], new_idx);
+ }
+
+ /* add new descriptors to the ring */
+ for (i = curr_size; i < new_size; i++) {
+ u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
+
+ ring[new_idx] = ioat_alloc_ring_ent(c, GFP_NOWAIT);
+ if (!ring[new_idx]) {
+ while (i--) {
+ u16 new_idx = (ioat_chan->tail+i) &
+ (new_size-1);
+
+ ioat_free_ring_ent(ring[new_idx], c);
+ }
+ kfree(ring);
+ return false;
+ }
+ set_desc_id(ring[new_idx], new_idx);
+ }
+
+ /* hw link new descriptors */
+ for (i = curr_size-1; i < new_size; i++) {
+ u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
+ struct ioat_ring_ent *next =
+ ring[(new_idx+1) & (new_size-1)];
+ struct ioat_dma_descriptor *hw = ring[new_idx]->hw;
+
+ hw->next = next->txd.phys;
+ }
+ } else {
+ struct ioat_dma_descriptor *hw;
+ struct ioat_ring_ent *next;
+
+ /* copy current descriptors to the new ring, dropping the
+ * removed descriptors
+ */
+ for (i = 0; i < new_size; i++) {
+ u16 curr_idx = (ioat_chan->tail+i) & (curr_size-1);
+ u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
+
+ ring[new_idx] = ioat_chan->ring[curr_idx];
+ set_desc_id(ring[new_idx], new_idx);
+ }
+
+ /* free deleted descriptors */
+ for (i = new_size; i < curr_size; i++) {
+ struct ioat_ring_ent *ent;
+
+ ent = ioat_get_ring_ent(ioat_chan, ioat_chan->tail+i);
+ ioat_free_ring_ent(ent, c);
+ }
+
+ /* fix up hardware ring */
+ hw = ring[(ioat_chan->tail+new_size-1) & (new_size-1)]->hw;
+ next = ring[(ioat_chan->tail+new_size) & (new_size-1)];
+ hw->next = next->txd.phys;
+ }
+
+ dev_dbg(to_dev(ioat_chan), "%s: allocated %d descriptors\n",
+ __func__, new_size);
+
+ kfree(ioat_chan->ring);
+ ioat_chan->ring = ring;
+ ioat_chan->alloc_order = order;
+
+ return true;
+}
+
+/**
+ * ioat_check_space_lock - verify space and grab ring producer lock
+ * @ioat: ioat,3 channel (ring) to operate on
+ * @num_descs: allocation length
+ */
+int ioat_check_space_lock(struct ioatdma_chan *ioat_chan, int num_descs)
+{
+ bool retry;
+
+ retry:
+ spin_lock_bh(&ioat_chan->prep_lock);
+ /* never allow the last descriptor to be consumed, we need at
+ * least one free at all times to allow for on-the-fly ring
+ * resizing.
+ */
+ if (likely(ioat_ring_space(ioat_chan) > num_descs)) {
+ dev_dbg(to_dev(ioat_chan), "%s: num_descs: %d (%x:%x:%x)\n",
+ __func__, num_descs, ioat_chan->head,
+ ioat_chan->tail, ioat_chan->issued);
+ ioat_chan->produce = num_descs;
+ return 0; /* with ioat->prep_lock held */
+ }
+ retry = test_and_set_bit(IOAT_RESHAPE_PENDING, &ioat_chan->state);
+ spin_unlock_bh(&ioat_chan->prep_lock);
+
+ /* is another cpu already trying to expand the ring? */
+ if (retry)
+ goto retry;
+
+ spin_lock_bh(&ioat_chan->cleanup_lock);
+ spin_lock_bh(&ioat_chan->prep_lock);
+ retry = reshape_ring(ioat_chan, ioat_chan->alloc_order + 1);
+ clear_bit(IOAT_RESHAPE_PENDING, &ioat_chan->state);
+ spin_unlock_bh(&ioat_chan->prep_lock);
+ spin_unlock_bh(&ioat_chan->cleanup_lock);
+
+ /* if we were able to expand the ring retry the allocation */
+ if (retry)
+ goto retry;
+
+ dev_dbg_ratelimited(to_dev(ioat_chan),
+ "%s: ring full! num_descs: %d (%x:%x:%x)\n",
+ __func__, num_descs, ioat_chan->head,
+ ioat_chan->tail, ioat_chan->issued);
+
+ /* progress reclaim in the allocation failure case we may be
+ * called under bh_disabled so we need to trigger the timer
+ * event directly
+ */
+ if (time_is_before_jiffies(ioat_chan->timer.expires)
+ && timer_pending(&ioat_chan->timer)) {
+ struct ioatdma_device *ioat_dma = ioat_chan->ioat_dma;
+
+ mod_timer(&ioat_chan->timer, jiffies + COMPLETION_TIMEOUT);
+ ioat_dma->timer_fn((unsigned long)ioat_chan);
+ }
+
+ return -ENOMEM;
+}
+
+struct dma_async_tx_descriptor *
+ioat_dma_prep_memcpy_lock(struct dma_chan *c, dma_addr_t dma_dest,
+ dma_addr_t dma_src, size_t len, unsigned long flags)
+{
+ struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+ struct ioat_dma_descriptor *hw;
+ struct ioat_ring_ent *desc;
+ dma_addr_t dst = dma_dest;
+ dma_addr_t src = dma_src;
+ size_t total_len = len;
+ int num_descs, idx, i;
+
+ num_descs = ioat_xferlen_to_descs(ioat_chan, len);
+ if (likely(num_descs) &&
+ ioat_check_space_lock(ioat_chan, num_descs) == 0)
+ idx = ioat_chan->head;
+ else
+ return NULL;
+ i = 0;
+ do {
+ size_t copy = min_t(size_t, len, 1 << ioat_chan->xfercap_log);
+
+ desc = ioat_get_ring_ent(ioat_chan, idx + i);
+ hw = desc->hw;
+
+ hw->size = copy;
+ hw->ctl = 0;
+ hw->src_addr = src;
+ hw->dst_addr = dst;
+
+ len -= copy;
+ dst += copy;
+ src += copy;
+ dump_desc_dbg(ioat_chan, desc);
+ } while (++i < num_descs);
+
+ desc->txd.flags = flags;
+ desc->len = total_len;
+ hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
+ hw->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
+ hw->ctl_f.compl_write = 1;
+ dump_desc_dbg(ioat_chan, desc);
+ /* we leave the channel locked to ensure in order submission */
+
+ return &desc->txd;
+}
+
+static ssize_t ring_size_show(struct dma_chan *c, char *page)
+{
+ struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+
+ return sprintf(page, "%d\n", (1 << ioat_chan->alloc_order) & ~1);
+}
+static struct ioat_sysfs_entry ring_size_attr = __ATTR_RO(ring_size);
+
+static ssize_t ring_active_show(struct dma_chan *c, char *page)
+{
+ struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+
+ /* ...taken outside the lock, no need to be precise */
+ return sprintf(page, "%d\n", ioat_ring_active(ioat_chan));
+}
+static struct ioat_sysfs_entry ring_active_attr = __ATTR_RO(ring_active);
+
+static struct attribute *ioat_attrs[] = {
+ &ring_size_attr.attr,
+ &ring_active_attr.attr,
+ &ioat_cap_attr.attr,
+ &ioat_version_attr.attr,
+ NULL,
+};
+
+struct kobj_type ioat_ktype = {
+ .sysfs_ops = &ioat_sysfs_ops,
+ .default_attrs = ioat_attrs,
+};