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path: root/drivers/gpu/drm/via/via_dmablit.c
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Diffstat (limited to 'drivers/gpu/drm/via/via_dmablit.c')
-rw-r--r--drivers/gpu/drm/via/via_dmablit.c816
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 00000000000..409e00afdd0
--- /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;
+}