drm/vmwgfx: Add DRM driver for VMware Virtual GPU

This commit adds the vmwgfx driver for the VWware Virtual GPU aka SVGA.
The driver is under staging the same as Nouveau and Radeon KMS. Hopefully
the 2D ioctls are bug free and don't need changing, so that part of the
API should be stable. But there there is a pretty big chance that the 3D API
will change in the future.

Signed-off-by: Thomas Hellström <thellstrom@vmware.com>
Signed-off-by: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 213 insertions, 0 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_gmr.c b/drivers/gpu/drm/vmwgfx/vmwgfx_gmr.c
new file mode 100644
index 000000000000..5f8908a5d7fd
--- /dev/null
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_gmr.c
@@ -0,0 +1,213 @@
+/**************************************************************************
+ *
+ * Copyright © 2009 VMware, Inc., Palo Alto, CA., USA
+ * 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.
+ *
+ **************************************************************************/
+
+#include "vmwgfx_drv.h"
+#include "drmP.h"
+#include "ttm/ttm_bo_driver.h"
+
+/**
+ * FIXME: Adjust to the ttm lowmem / highmem storage to minimize
+ * the number of used descriptors.
+ */
+
+static int vmw_gmr_build_descriptors(struct list_head *desc_pages,
+				     struct page *pages[],
+				     unsigned long num_pages)
+{
+	struct page *page, *next;
+	struct svga_guest_mem_descriptor *page_virtual = NULL;
+	struct svga_guest_mem_descriptor *desc_virtual = NULL;
+	unsigned int desc_per_page;
+	unsigned long prev_pfn;
+	unsigned long pfn;
+	int ret;
+
+	desc_per_page = PAGE_SIZE /
+	    sizeof(struct svga_guest_mem_descriptor) - 1;
+
+	while (likely(num_pages != 0)) {
+		page = alloc_page(__GFP_HIGHMEM);
+		if (unlikely(page == NULL)) {
+			ret = -ENOMEM;
+			goto out_err;
+		}
+
+		list_add_tail(&page->lru, desc_pages);
+
+		/*
+		 * Point previous page terminating descriptor to this
+		 * page before unmapping it.
+		 */
+
+		if (likely(page_virtual != NULL)) {
+			desc_virtual->ppn = page_to_pfn(page);
+			kunmap_atomic(page_virtual, KM_USER0);
+		}
+
+		page_virtual = kmap_atomic(page, KM_USER0);
+		desc_virtual = page_virtual - 1;
+		prev_pfn = ~(0UL);
+
+		while (likely(num_pages != 0)) {
+			pfn = page_to_pfn(*pages);
+
+			if (pfn != prev_pfn + 1) {
+
+				if (desc_virtual - page_virtual ==
+				    desc_per_page - 1)
+					break;
+
+				(++desc_virtual)->ppn = cpu_to_le32(pfn);
+				desc_virtual->num_pages = cpu_to_le32(1);
+			} else {
+				uint32_t tmp =
+				    le32_to_cpu(desc_virtual->num_pages);
+				desc_virtual->num_pages = cpu_to_le32(tmp + 1);
+			}
+			prev_pfn = pfn;
+			--num_pages;
+			++pages;
+		}
+
+		(++desc_virtual)->ppn = cpu_to_le32(0);
+		desc_virtual->num_pages = cpu_to_le32(0);
+	}
+
+	if (likely(page_virtual != NULL))
+		kunmap_atomic(page_virtual, KM_USER0);
+
+	return 0;
+out_err:
+	list_for_each_entry_safe(page, next, desc_pages, lru) {
+		list_del_init(&page->lru);
+		__free_page(page);
+	}
+	return ret;
+}
+
+static inline void vmw_gmr_free_descriptors(struct list_head *desc_pages)
+{
+	struct page *page, *next;
+
+	list_for_each_entry_safe(page, next, desc_pages, lru) {
+		list_del_init(&page->lru);
+		__free_page(page);
+	}
+}
+
+static void vmw_gmr_fire_descriptors(struct vmw_private *dev_priv,
+				     int gmr_id, struct list_head *desc_pages)
+{
+	struct page *page;
+
+	if (unlikely(list_empty(desc_pages)))
+		return;
+
+	page = list_entry(desc_pages->next, struct page, lru);
+
+	mutex_lock(&dev_priv->hw_mutex);
+
+	vmw_write(dev_priv, SVGA_REG_GMR_ID, gmr_id);
+	wmb();
+	vmw_write(dev_priv, SVGA_REG_GMR_DESCRIPTOR, page_to_pfn(page));
+	mb();
+
+	mutex_unlock(&dev_priv->hw_mutex);
+
+}
+
+/**
+ * FIXME: Adjust to the ttm lowmem / highmem storage to minimize
+ * the number of used descriptors.
+ */
+
+static unsigned long vmw_gmr_count_descriptors(struct page *pages[],
+					       unsigned long num_pages)
+{
+	unsigned long prev_pfn = ~(0UL);
+	unsigned long pfn;
+	unsigned long descriptors = 0;
+
+	while (num_pages--) {
+		pfn = page_to_pfn(*pages++);
+		if (prev_pfn + 1 != pfn)
+			++descriptors;
+		prev_pfn = pfn;
+	}
+
+	return descriptors;
+}
+
+int vmw_gmr_bind(struct vmw_private *dev_priv,
+		 struct ttm_buffer_object *bo)
+{
+	struct ttm_tt *ttm = bo->ttm;
+	unsigned long descriptors;
+	int ret;
+	uint32_t id;
+	struct list_head desc_pages;
+
+	if (!(dev_priv->capabilities & SVGA_CAP_GMR))
+		return -EINVAL;
+
+	ret = ttm_tt_populate(ttm);
+	if (unlikely(ret != 0))
+		return ret;
+
+	descriptors = vmw_gmr_count_descriptors(ttm->pages, ttm->num_pages);
+	if (unlikely(descriptors > dev_priv->max_gmr_descriptors))
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&desc_pages);
+	ret = vmw_gmr_build_descriptors(&desc_pages, ttm->pages,
+					ttm->num_pages);
+	if (unlikely(ret != 0))
+		return ret;
+
+	ret = vmw_gmr_id_alloc(dev_priv, &id);
+	if (unlikely(ret != 0))
+		goto out_no_id;
+
+	vmw_gmr_fire_descriptors(dev_priv, id, &desc_pages);
+	vmw_gmr_free_descriptors(&desc_pages);
+	vmw_dmabuf_set_gmr(bo, id);
+	return 0;
+
+out_no_id:
+	vmw_gmr_free_descriptors(&desc_pages);
+	return ret;
+}
+
+void vmw_gmr_unbind(struct vmw_private *dev_priv, int gmr_id)
+{
+	mutex_lock(&dev_priv->hw_mutex);
+	vmw_write(dev_priv, SVGA_REG_GMR_ID, gmr_id);
+	wmb();
+	vmw_write(dev_priv, SVGA_REG_GMR_DESCRIPTOR, 0);
+	mb();
+	mutex_unlock(&dev_priv->hw_mutex);
+}