1 files changed, 816 insertions, 0 deletions

diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
new file mode 100644
index 0000000..409e00a
--- /dev/null
+++ b/drivers/gpu/drm/via/via_dmablit.c
@@ -0,0 +1,816 @@
+/* via_dmablit.c -- PCI DMA BitBlt support for the VIA Unichrome/Pro
+ *
+ * Copyright (C) 2005 Thomas Hellstrom, All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sub license,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Thomas Hellstrom.
+ *    Partially based on code obtained from Digeo Inc.
+ */
+
+
+/*
+ * Unmaps the DMA mappings.
+ * FIXME: Is this a NoOp on x86? Also
+ * FIXME: What happens if this one is called and a pending blit has previously done
+ * the same DMA mappings?
+ */
+
+#include "drmP.h"
+#include "via_drm.h"
+#include "via_drv.h"
+#include "via_dmablit.h"
+
+#include <linux/pagemap.h>
+
+#define VIA_PGDN(x)	     (((unsigned long)(x)) & PAGE_MASK)
+#define VIA_PGOFF(x)	    (((unsigned long)(x)) & ~PAGE_MASK)
+#define VIA_PFN(x)	      ((unsigned long)(x) >> PAGE_SHIFT)
+
+typedef struct _drm_via_descriptor {
+	uint32_t mem_addr;
+	uint32_t dev_addr;
+	uint32_t size;
+	uint32_t next;
+} drm_via_descriptor_t;
+
+
+/*
+ * Unmap a DMA mapping.
+ */
+
+
+
+static void
+via_unmap_blit_from_device(struct pci_dev *pdev, drm_via_sg_info_t *vsg)
+{
+	int num_desc = vsg->num_desc;
+	unsigned cur_descriptor_page = num_desc / vsg->descriptors_per_page;
+	unsigned descriptor_this_page = num_desc % vsg->descriptors_per_page;
+	drm_via_descriptor_t *desc_ptr = vsg->desc_pages[cur_descriptor_page] +
+		descriptor_this_page;
+	dma_addr_t next = vsg->chain_start;
+
+	while(num_desc--) {
+		if (descriptor_this_page-- == 0) {
+			cur_descriptor_page--;
+			descriptor_this_page = vsg->descriptors_per_page - 1;
+			desc_ptr = vsg->desc_pages[cur_descriptor_page] +
+				descriptor_this_page;
+		}
+		dma_unmap_single(&pdev->dev, next, sizeof(*desc_ptr), DMA_TO_DEVICE);
+		dma_unmap_page(&pdev->dev, desc_ptr->mem_addr, desc_ptr->size, vsg->direction);
+		next = (dma_addr_t) desc_ptr->next;
+		desc_ptr--;
+	}
+}
+
+/*
+ * If mode = 0, count how many descriptors are needed.
+ * If mode = 1, Map the DMA pages for the device, put together and map also the descriptors.
+ * Descriptors are run in reverse order by the hardware because we are not allowed to update the
+ * 'next' field without syncing calls when the descriptor is already mapped.
+ */
+
+static void
+via_map_blit_for_device(struct pci_dev *pdev,
+		   const drm_via_dmablit_t *xfer,
+		   drm_via_sg_info_t *vsg,
+		   int mode)
+{
+	unsigned cur_descriptor_page = 0;
+	unsigned num_descriptors_this_page = 0;
+	unsigned char *mem_addr = xfer->mem_addr;
+	unsigned char *cur_mem;
+	unsigned char *first_addr = (unsigned char *)VIA_PGDN(mem_addr);
+	uint32_t fb_addr = xfer->fb_addr;
+	uint32_t cur_fb;
+	unsigned long line_len;
+	unsigned remaining_len;
+	int num_desc = 0;
+	int cur_line;
+	dma_addr_t next = 0 | VIA_DMA_DPR_EC;
+	drm_via_descriptor_t *desc_ptr = NULL;
+
+	if (mode == 1)
+		desc_ptr = vsg->desc_pages[cur_descriptor_page];
+
+	for (cur_line = 0; cur_line < xfer->num_lines; ++cur_line) {
+
+		line_len = xfer->line_length;
+		cur_fb = fb_addr;
+		cur_mem = mem_addr;
+
+		while (line_len > 0) {
+
+			remaining_len = min(PAGE_SIZE-VIA_PGOFF(cur_mem), line_len);
+			line_len -= remaining_len;
+
+			if (mode == 1) {
+				desc_ptr->mem_addr =
+					dma_map_page(&pdev->dev,
+						     vsg->pages[VIA_PFN(cur_mem) -
+								VIA_PFN(first_addr)],
+						     VIA_PGOFF(cur_mem), remaining_len,
+						     vsg->direction);
+				desc_ptr->dev_addr = cur_fb;
+
+				desc_ptr->size = remaining_len;
+				desc_ptr->next = (uint32_t) next;
+				next = dma_map_single(&pdev->dev, desc_ptr, sizeof(*desc_ptr),
+						      DMA_TO_DEVICE);
+				desc_ptr++;
+				if (++num_descriptors_this_page >= vsg->descriptors_per_page) {
+					num_descriptors_this_page = 0;
+					desc_ptr = vsg->desc_pages[++cur_descriptor_page];
+				}
+			}
+
+			num_desc++;
+			cur_mem += remaining_len;
+			cur_fb += remaining_len;
+		}
+
+		mem_addr += xfer->mem_stride;
+		fb_addr += xfer->fb_stride;
+	}
+
+	if (mode == 1) {
+		vsg->chain_start = next;
+		vsg->state = dr_via_device_mapped;
+	}
+	vsg->num_desc = num_desc;
+}
+
+/*
+ * Function that frees up all resources for a blit. It is usable even if the
+ * blit info has only been partially built as long as the status enum is consistent
+ * with the actual status of the used resources.
+ */
+
+
+static void
+via_free_sg_info(struct pci_dev *pdev, drm_via_sg_info_t *vsg)
+{
+	struct page *page;
+	int i;
+
+	switch(vsg->state) {
+	case dr_via_device_mapped:
+		via_unmap_blit_from_device(pdev, vsg);
+	case dr_via_desc_pages_alloc:
+		for (i=0; i<vsg->num_desc_pages; ++i) {
+			if (vsg->desc_pages[i] != NULL)
+			  free_page((unsigned long)vsg->desc_pages[i]);
+		}
+		kfree(vsg->desc_pages);
+	case dr_via_pages_locked:
+		for (i=0; i<vsg->num_pages; ++i) {
+			if ( NULL != (page = vsg->pages[i])) {
+				if (! PageReserved(page) && (DMA_FROM_DEVICE == vsg->direction))
+					SetPageDirty(page);
+				page_cache_release(page);
+			}
+		}
+	case dr_via_pages_alloc:
+		vfree(vsg->pages);
+	default:
+		vsg->state = dr_via_sg_init;
+	}
+	if (vsg->bounce_buffer) {
+		vfree(vsg->bounce_buffer);
+		vsg->bounce_buffer = NULL;
+	}
+	vsg->free_on_sequence = 0;
+}
+
+/*
+ * Fire a blit engine.
+ */
+
+static void
+via_fire_dmablit(struct drm_device *dev, drm_via_sg_info_t *vsg, int engine)
+{
+	drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
+
+	VIA_WRITE(VIA_PCI_DMA_MAR0 + engine*0x10, 0);
+	VIA_WRITE(VIA_PCI_DMA_DAR0 + engine*0x10, 0);
+	VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04, VIA_DMA_CSR_DD | VIA_DMA_CSR_TD |
+		  VIA_DMA_CSR_DE);
+	VIA_WRITE(VIA_PCI_DMA_MR0  + engine*0x04, VIA_DMA_MR_CM | VIA_DMA_MR_TDIE);
+	VIA_WRITE(VIA_PCI_DMA_BCR0 + engine*0x10, 0);
+	VIA_WRITE(VIA_PCI_DMA_DPR0 + engine*0x10, vsg->chain_start);
+	DRM_WRITEMEMORYBARRIER();
+	VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04, VIA_DMA_CSR_DE | VIA_DMA_CSR_TS);
+	VIA_READ(VIA_PCI_DMA_CSR0 + engine*0x04);
+}
+
+/*
+ * Obtain a page pointer array and lock all pages into system memory. A segmentation violation will
+ * occur here if the calling user does not have access to the submitted address.
+ */
+
+static int
+via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
+{
+	int ret;
+	unsigned long first_pfn = VIA_PFN(xfer->mem_addr);
+	vsg->num_pages = VIA_PFN(xfer->mem_addr + (xfer->num_lines * xfer->mem_stride -1)) -
+		first_pfn + 1;
+
+	if (NULL == (vsg->pages = vmalloc(sizeof(struct page *) * vsg->num_pages)))
+		return -ENOMEM;
+	memset(vsg->pages, 0, sizeof(struct page *) * vsg->num_pages);
+	down_read(&current->mm->mmap_sem);
+	ret = get_user_pages(current, current->mm,
+			     (unsigned long)xfer->mem_addr,
+			     vsg->num_pages,
+			     (vsg->direction == DMA_FROM_DEVICE),
+			     0, vsg->pages, NULL);
+
+	up_read(&current->mm->mmap_sem);
+	if (ret != vsg->num_pages) {
+		if (ret < 0)
+			return ret;
+		vsg->state = dr_via_pages_locked;
+		return -EINVAL;
+	}
+	vsg->state = dr_via_pages_locked;
+	DRM_DEBUG("DMA pages locked\n");
+	return 0;
+}
+
+/*
+ * Allocate DMA capable memory for the blit descriptor chain, and an array that keeps track of the
+ * pages we allocate. We don't want to use kmalloc for the descriptor chain because it may be
+ * quite large for some blits, and pages don't need to be contingous.
+ */
+
+static int
+via_alloc_desc_pages(drm_via_sg_info_t *vsg)
+{
+	int i;
+
+	vsg->descriptors_per_page = PAGE_SIZE / sizeof( drm_via_descriptor_t);
+	vsg->num_desc_pages = (vsg->num_desc + vsg->descriptors_per_page - 1) /
+		vsg->descriptors_per_page;
+
+	if (NULL ==  (vsg->desc_pages = kcalloc(vsg->num_desc_pages, sizeof(void *), GFP_KERNEL)))
+		return -ENOMEM;
+
+	vsg->state = dr_via_desc_pages_alloc;
+	for (i=0; i<vsg->num_desc_pages; ++i) {
+		if (NULL == (vsg->desc_pages[i] =
+			     (drm_via_descriptor_t *) __get_free_page(GFP_KERNEL)))
+			return -ENOMEM;
+	}
+	DRM_DEBUG("Allocated %d pages for %d descriptors.\n", vsg->num_desc_pages,
+		  vsg->num_desc);
+	return 0;
+}
+
+static void
+via_abort_dmablit(struct drm_device *dev, int engine)
+{
+	drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
+
+	VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04, VIA_DMA_CSR_TA);
+}
+
+static void
+via_dmablit_engine_off(struct drm_device *dev, int engine)
+{
+	drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
+
+	VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04, VIA_DMA_CSR_TD | VIA_DMA_CSR_DD);
+}
+
+
+
+/*
+ * The dmablit part of the IRQ handler. Trying to do only reasonably fast things here.
+ * The rest, like unmapping and freeing memory for done blits is done in a separate workqueue
+ * task. Basically the task of the interrupt handler is to submit a new blit to the engine, while
+ * the workqueue task takes care of processing associated with the old blit.
+ */
+
+void
+via_dmablit_handler(struct drm_device *dev, int engine, int from_irq)
+{
+	drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
+	drm_via_blitq_t *blitq = dev_priv->blit_queues + engine;
+	int cur;
+	int done_transfer;
+	unsigned long irqsave=0;
+	uint32_t status = 0;
+
+	DRM_DEBUG("DMA blit handler called. engine = %d, from_irq = %d, blitq = 0x%lx\n",
+		  engine, from_irq, (unsigned long) blitq);
+
+	if (from_irq) {
+		spin_lock(&blitq->blit_lock);
+	} else {
+		spin_lock_irqsave(&blitq->blit_lock, irqsave);
+	}
+
+	done_transfer = blitq->is_active &&
+	  (( status = VIA_READ(VIA_PCI_DMA_CSR0 + engine*0x04)) & VIA_DMA_CSR_TD);
+	done_transfer = done_transfer || ( blitq->aborting && !(status & VIA_DMA_CSR_DE));
+
+	cur = blitq->cur;
+	if (done_transfer) {
+
+		blitq->blits[cur]->aborted = blitq->aborting;
+		blitq->done_blit_handle++;
+		DRM_WAKEUP(blitq->blit_queue + cur);
+
+		cur++;
+		if (cur >= VIA_NUM_BLIT_SLOTS)
+			cur = 0;
+		blitq->cur = cur;
+
+		/*
+		 * Clear transfer done flag.
+		 */
+
+		VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04,  VIA_DMA_CSR_TD);
+
+		blitq->is_active = 0;
+		blitq->aborting = 0;
+		schedule_work(&blitq->wq);
+
+	} else if (blitq->is_active && time_after_eq(jiffies, blitq->end)) {
+
+		/*
+		 * Abort transfer after one second.
+		 */
+
+		via_abort_dmablit(dev, engine);
+		blitq->aborting = 1;
+		blitq->end = jiffies + DRM_HZ;
+	}
+
+	if (!blitq->is_active) {
+		if (blitq->num_outstanding) {
+			via_fire_dmablit(dev, blitq->blits[cur], engine);
+			blitq->is_active = 1;
+			blitq->cur = cur;
+			blitq->num_outstanding--;
+			blitq->end = jiffies + DRM_HZ;
+			if (!timer_pending(&blitq->poll_timer))
+				mod_timer(&blitq->poll_timer, jiffies + 1);
+		} else {
+			if (timer_pending(&blitq->poll_timer)) {
+				del_timer(&blitq->poll_timer);
+			}
+			via_dmablit_engine_off(dev, engine);
+		}
+	}
+
+	if (from_irq) {
+		spin_unlock(&blitq->blit_lock);
+	} else {
+		spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
+	}
+}
+
+
+
+/*
+ * Check whether this blit is still active, performing necessary locking.
+ */
+
+static int
+via_dmablit_active(drm_via_blitq_t *blitq, int engine, uint32_t handle, wait_queue_head_t **queue)
+{
+	unsigned long irqsave;
+	uint32_t slot;
+	int active;
+
+	spin_lock_irqsave(&blitq->blit_lock, irqsave);
+
+	/*
+	 * Allow for handle wraparounds.
+	 */
+
+	active = ((blitq->done_blit_handle - handle) > (1 << 23)) &&
+		((blitq->cur_blit_handle - handle) <= (1 << 23));
+
+	if (queue && active) {
+		slot = handle - blitq->done_blit_handle + blitq->cur -1;
+		if (slot >= VIA_NUM_BLIT_SLOTS) {
+			slot -= VIA_NUM_BLIT_SLOTS;
+		}
+		*queue = blitq->blit_queue + slot;
+	}
+
+	spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
+
+	return active;
+}
+
+/*
+ * Sync. Wait for at least three seconds for the blit to be performed.
+ */
+
+static int
+via_dmablit_sync(struct drm_device *dev, uint32_t handle, int engine)
+{
+
+	drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
+	drm_via_blitq_t *blitq = dev_priv->blit_queues + engine;
+	wait_queue_head_t *queue;
+	int ret = 0;
+
+	if (via_dmablit_active(blitq, engine, handle, &queue)) {
+		DRM_WAIT_ON(ret, *queue, 3 * DRM_HZ,
+			    !via_dmablit_active(blitq, engine, handle, NULL));
+	}
+	DRM_DEBUG("DMA blit sync handle 0x%x engine %d returned %d\n",
+		  handle, engine, ret);
+
+	return ret;
+}
+
+
+/*
+ * A timer that regularly polls the blit engine in cases where we don't have interrupts:
+ * a) Broken hardware (typically those that don't have any video capture facility).
+ * b) Blit abort. The hardware doesn't send an interrupt when a blit is aborted.
+ * The timer and hardware IRQ's can and do work in parallel. If the hardware has
+ * irqs, it will shorten the latency somewhat.
+ */
+
+
+
+static void
+via_dmablit_timer(unsigned long data)
+{
+	drm_via_blitq_t *blitq = (drm_via_blitq_t *) data;
+	struct drm_device *dev = blitq->dev;
+	int engine = (int)
+		(blitq - ((drm_via_private_t *)dev->dev_private)->blit_queues);
+
+	DRM_DEBUG("Polling timer called for engine %d, jiffies %lu\n", engine,
+		  (unsigned long) jiffies);
+
+	via_dmablit_handler(dev, engine, 0);
+
+	if (!timer_pending(&blitq->poll_timer)) {
+		mod_timer(&blitq->poll_timer, jiffies + 1);
+
+	       /*
+		* Rerun handler to delete timer if engines are off, and
+		* to shorten abort latency. This is a little nasty.
+		*/
+
+	       via_dmablit_handler(dev, engine, 0);
+
+	}
+}
+
+
+
+
+/*
+ * Workqueue task that frees data and mappings associated with a blit.
+ * Also wakes up waiting processes. Each of these tasks handles one
+ * blit engine only and may not be called on each interrupt.
+ */
+
+
+static void
+via_dmablit_workqueue(struct work_struct *work)
+{
+	drm_via_blitq_t *blitq = container_of(work, drm_via_blitq_t, wq);
+	struct drm_device *dev = blitq->dev;
+	unsigned long irqsave;
+	drm_via_sg_info_t *cur_sg;
+	int cur_released;
+
+
+	DRM_DEBUG("Workqueue task called for blit engine %ld\n",(unsigned long)
+		  (blitq - ((drm_via_private_t *)dev->dev_private)->blit_queues));
+
+	spin_lock_irqsave(&blitq->blit_lock, irqsave);
+
+	while(blitq->serviced != blitq->cur) {
+
+		cur_released = blitq->serviced++;
+
+		DRM_DEBUG("Releasing blit slot %d\n", cur_released);
+
+		if (blitq->serviced >= VIA_NUM_BLIT_SLOTS)
+			blitq->serviced = 0;
+
+		cur_sg = blitq->blits[cur_released];
+		blitq->num_free++;
+
+		spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
+
+		DRM_WAKEUP(&blitq->busy_queue);
+
+		via_free_sg_info(dev->pdev, cur_sg);
+		kfree(cur_sg);
+
+		spin_lock_irqsave(&blitq->blit_lock, irqsave);
+	}
+
+	spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
+}
+
+
+/*
+ * Init all blit engines. Currently we use two, but some hardware have 4.
+ */
+
+
+void
+via_init_dmablit(struct drm_device *dev)
+{
+	int i,j;
+	drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
+	drm_via_blitq_t *blitq;
+
+	pci_set_master(dev->pdev);
+
+	for (i=0; i< VIA_NUM_BLIT_ENGINES; ++i) {
+		blitq = dev_priv->blit_queues + i;
+		blitq->dev = dev;
+		blitq->cur_blit_handle = 0;
+		blitq->done_blit_handle = 0;
+		blitq->head = 0;
+		blitq->cur = 0;
+		blitq->serviced = 0;
+		blitq->num_free = VIA_NUM_BLIT_SLOTS - 1;
+		blitq->num_outstanding = 0;
+		blitq->is_active = 0;
+		blitq->aborting = 0;
+		spin_lock_init(&blitq->blit_lock);
+		for (j=0; j<VIA_NUM_BLIT_SLOTS; ++j) {
+			DRM_INIT_WAITQUEUE(blitq->blit_queue + j);
+		}
+		DRM_INIT_WAITQUEUE(&blitq->busy_queue);
+		INIT_WORK(&blitq->wq, via_dmablit_workqueue);
+		setup_timer(&blitq->poll_timer, via_dmablit_timer,
+				(unsigned long)blitq);
+	}
+}
+
+/*
+ * Build all info and do all mappings required for a blit.
+ */
+
+
+static int
+via_build_sg_info(struct drm_device *dev, drm_via_sg_info_t *vsg, drm_via_dmablit_t *xfer)
+{
+	int draw = xfer->to_fb;
+	int ret = 0;
+
+	vsg->direction = (draw) ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
+	vsg->bounce_buffer = NULL;
+
+	vsg->state = dr_via_sg_init;
+
+	if (xfer->num_lines <= 0 || xfer->line_length <= 0) {
+		DRM_ERROR("Zero size bitblt.\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Below check is a driver limitation, not a hardware one. We
+	 * don't want to lock unused pages, and don't want to incoporate the
+	 * extra logic of avoiding them. Make sure there are no.
+	 * (Not a big limitation anyway.)
+	 */
+
+	if ((xfer->mem_stride - xfer->line_length) > 2*PAGE_SIZE) {
+		DRM_ERROR("Too large system memory stride. Stride: %d, "
+			  "Length: %d\n", xfer->mem_stride, xfer->line_length);
+		return -EINVAL;
+	}
+
+	if ((xfer->mem_stride == xfer->line_length) &&
+	   (xfer->fb_stride == xfer->line_length)) {
+		xfer->mem_stride *= xfer->num_lines;
+		xfer->line_length = xfer->mem_stride;
+		xfer->fb_stride = xfer->mem_stride;
+		xfer->num_lines = 1;
+	}
+
+	/*
+	 * Don't lock an arbitrary large number of pages, since that causes a
+	 * DOS security hole.
+	 */
+
+	if (xfer->num_lines > 2048 || (xfer->num_lines*xfer->mem_stride > (2048*2048*4))) {
+		DRM_ERROR("Too large PCI DMA bitblt.\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * we allow a negative fb stride to allow flipping of images in
+	 * transfer.
+	 */
+
+	if (xfer->mem_stride < xfer->line_length ||
+		abs(xfer->fb_stride) < xfer->line_length) {
+		DRM_ERROR("Invalid frame-buffer / memory stride.\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * A hardware bug seems to be worked around if system memory addresses start on
+	 * 16 byte boundaries. This seems a bit restrictive however. VIA is contacted
+	 * about this. Meanwhile, impose the following restrictions:
+	 */
+
+#ifdef VIA_BUGFREE
+	if ((((unsigned long)xfer->mem_addr & 3) != ((unsigned long)xfer->fb_addr & 3)) ||
+	    ((xfer->num_lines > 1) && ((xfer->mem_stride & 3) != (xfer->fb_stride & 3)))) {
+		DRM_ERROR("Invalid DRM bitblt alignment.\n");
+		return -EINVAL;
+	}
+#else
+	if ((((unsigned long)xfer->mem_addr & 15) ||
+	      ((unsigned long)xfer->fb_addr & 3)) ||
+	   ((xfer->num_lines > 1) &&
+	   ((xfer->mem_stride & 15) || (xfer->fb_stride & 3)))) {
+		DRM_ERROR("Invalid DRM bitblt alignment.\n");
+		return -EINVAL;
+	}
+#endif
+
+	if (0 != (ret = via_lock_all_dma_pages(vsg, xfer))) {
+		DRM_ERROR("Could not lock DMA pages.\n");
+		via_free_sg_info(dev->pdev, vsg);
+		return ret;
+	}
+
+	via_map_blit_for_device(dev->pdev, xfer, vsg, 0);
+	if (0 != (ret = via_alloc_desc_pages(vsg))) {
+		DRM_ERROR("Could not allocate DMA descriptor pages.\n");
+		via_free_sg_info(dev->pdev, vsg);
+		return ret;
+	}
+	via_map_blit_for_device(dev->pdev, xfer, vsg, 1);
+
+	return 0;
+}
+
+
+/*
+ * Reserve one free slot in the blit queue. Will wait for one second for one
+ * to become available. Otherwise -EBUSY is returned.
+ */
+
+static int
+via_dmablit_grab_slot(drm_via_blitq_t *blitq, int engine)
+{
+	int ret=0;
+	unsigned long irqsave;
+
+	DRM_DEBUG("Num free is %d\n", blitq->num_free);
+	spin_lock_irqsave(&blitq->blit_lock, irqsave);
+	while(blitq->num_free == 0) {
+		spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
+
+		DRM_WAIT_ON(ret, blitq->busy_queue, DRM_HZ, blitq->num_free > 0);
+		if (ret) {
+			return (-EINTR == ret) ? -EAGAIN : ret;
+		}
+
+		spin_lock_irqsave(&blitq->blit_lock, irqsave);
+	}
+
+	blitq->num_free--;
+	spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
+
+	return 0;
+}
+
+/*
+ * Hand back a free slot if we changed our mind.
+ */
+
+static void
+via_dmablit_release_slot(drm_via_blitq_t *blitq)
+{
+	unsigned long irqsave;
+
+	spin_lock_irqsave(&blitq->blit_lock, irqsave);
+	blitq->num_free++;
+	spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
+	DRM_WAKEUP( &blitq->busy_queue );
+}
+
+/*
+ * Grab a free slot. Build blit info and queue a blit.
+ */
+
+
+static int
+via_dmablit(struct drm_device *dev, drm_via_dmablit_t *xfer)
+{
+	drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
+	drm_via_sg_info_t *vsg;
+	drm_via_blitq_t *blitq;
+	int ret;
+	int engine;
+	unsigned long irqsave;
+
+	if (dev_priv == NULL) {
+		DRM_ERROR("Called without initialization.\n");
+		return -EINVAL;
+	}
+
+	engine = (xfer->to_fb) ? 0 : 1;
+	blitq = dev_priv->blit_queues + engine;
+	if (0 != (ret = via_dmablit_grab_slot(blitq, engine))) {
+		return ret;
+	}
+	if (NULL == (vsg = kmalloc(sizeof(*vsg), GFP_KERNEL))) {
+		via_dmablit_release_slot(blitq);
+		return -ENOMEM;
+	}
+	if (0 != (ret = via_build_sg_info(dev, vsg, xfer))) {
+		via_dmablit_release_slot(blitq);
+		kfree(vsg);
+		return ret;
+	}
+	spin_lock_irqsave(&blitq->blit_lock, irqsave);
+
+	blitq->blits[blitq->head++] = vsg;
+	if (blitq->head >= VIA_NUM_BLIT_SLOTS)
+		blitq->head = 0;
+	blitq->num_outstanding++;
+	xfer->sync.sync_handle = ++blitq->cur_blit_handle;
+
+	spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
+	xfer->sync.engine = engine;
+
+	via_dmablit_handler(dev, engine, 0);
+
+	return 0;
+}
+
+/*
+ * Sync on a previously submitted blit. Note that the X server use signals extensively, and
+ * that there is a very big probability that this IOCTL will be interrupted by a signal. In that
+ * case it returns with -EAGAIN for the signal to be delivered.
+ * The caller should then reissue the IOCTL. This is similar to what is being done for drmGetLock().
+ */
+
+int
+via_dma_blit_sync( struct drm_device *dev, void *data, struct drm_file *file_priv )
+{
+	drm_via_blitsync_t *sync = data;
+	int err;
+
+	if (sync->engine >= VIA_NUM_BLIT_ENGINES)
+		return -EINVAL;
+
+	err = via_dmablit_sync(dev, sync->sync_handle, sync->engine);
+
+	if (-EINTR == err)
+		err = -EAGAIN;
+
+	return err;
+}
+
+
+/*
+ * Queue a blit and hand back a handle to be used for sync. This IOCTL may be interrupted by a signal
+ * while waiting for a free slot in the blit queue. In that case it returns with -EAGAIN and should
+ * be reissued. See the above IOCTL code.
+ */
+
+int
+via_dma_blit( struct drm_device *dev, void *data, struct drm_file *file_priv )
+{
+	drm_via_dmablit_t *xfer = data;
+	int err;
+
+	err = via_dmablit(dev, xfer);
+
+	return err;
+}