drm/ttm: ttm_fault callback to allow driver to handle bo placement V6

On fault the driver is given the opportunity to perform any operation
it sees fit in order to place the buffer into a CPU visible area of
memory. This patch doesn't break TTM users, nouveau, vmwgfx and radeon
should keep working properly. Future patch will take advantage of this
infrastructure and remove the old path from TTM once driver are
converted.

V2 return VM_FAULT_NOPAGE if callback return -EBUSY or -ERESTARTSYS
V3 balance io_mem_reserve and io_mem_free call, fault_reserve_notify
   is responsible to perform any necessary task for mapping to succeed
V4 minor cleanup, atomic_t -> bool as member is protected by reserve
   mecanism from concurent access
V5 the callback is now responsible for iomapping the bo and providing
   a virtual address this simplify TTM and will allow to get rid of
   TTM_MEMTYPE_FLAG_NEEDS_IOREMAP
V6 use the bus addr data to decide to ioremap or this isn't needed
   but we don't necesarily need to ioremap in the callback but still
   allow driver to use static mapping
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/ttm/ttm_bo.c

@@ -632,6 +632,7 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bool interruptible,
 
 	evict_mem = bo->mem;
 	evict_mem.mm_node = NULL;
+	evict_mem.bus.io_reserved = false;
 
 	placement.fpfn = 0;
 	placement.lpfn = 0;
@@ -1005,6 +1006,7 @@ int ttm_bo_move_buffer(struct ttm_buffer_object *bo,
 	mem.num_pages = bo->num_pages;
 	mem.size = mem.num_pages << PAGE_SHIFT;
 	mem.page_alignment = bo->mem.page_alignment;
+	mem.bus.io_reserved = false;
 	/*
 	 * Determine where to move the buffer.
 	 */
@@ -1160,6 +1162,7 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
 	bo->mem.num_pages = bo->num_pages;
 	bo->mem.mm_node = NULL;
 	bo->mem.page_alignment = page_alignment;
+	bo->mem.bus.io_reserved = false;
 	bo->buffer_start = buffer_start & PAGE_MASK;
 	bo->priv_flags = 0;
 	bo->mem.placement = (TTM_PL_FLAG_SYSTEM | TTM_PL_FLAG_CACHED);
@@ -1574,7 +1577,7 @@ int ttm_bo_pci_offset(struct ttm_bo_device *bdev,
 	if (ttm_mem_reg_is_pci(bdev, mem)) {
 		*bus_offset = mem->mm_node->start << PAGE_SHIFT;
 		*bus_size = mem->num_pages << PAGE_SHIFT;
-		*bus_base = man->io_offset;
+		*bus_base = man->io_offset + (uintptr_t)man->io_addr;
 	}
 
 	return 0;
@@ -1588,8 +1591,8 @@ void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo)
 
 	if (!bdev->dev_mapping)
 		return;
-
 	unmap_mapping_range(bdev->dev_mapping, offset, holelen, 1);
+	ttm_mem_io_free(bdev, &bo->mem);
 }
 EXPORT_SYMBOL(ttm_bo_unmap_virtual);
 

drivers/gpu/drm/ttm/ttm_bo_util.c

@@ -81,30 +81,62 @@ int ttm_bo_move_ttm(struct ttm_buffer_object *bo,
 }
 EXPORT_SYMBOL(ttm_bo_move_ttm);
 
+int ttm_mem_io_reserve(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
+{
+	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
+	int ret;
+
+	if (bdev->driver->io_mem_reserve) {
+		if (!mem->bus.io_reserved) {
+			mem->bus.io_reserved = true;
+			ret = bdev->driver->io_mem_reserve(bdev, mem);
+			if (unlikely(ret != 0))
+				return ret;
+		}
+	} else {
+		ret = ttm_bo_pci_offset(bdev, mem, &mem->bus.base, &mem->bus.offset, &mem->bus.size);
+		if (unlikely(ret != 0))
+			return ret;
+		mem->bus.addr = NULL;
+		if (!(man->flags & TTM_MEMTYPE_FLAG_NEEDS_IOREMAP))
+			mem->bus.addr = (void *)(((u8 *)man->io_addr) + mem->bus.offset);
+		mem->bus.is_iomem = (mem->bus.size > 0) ? 1 : 0;
+	}
+	return 0;
+}
+
+void ttm_mem_io_free(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
+{
+	if (bdev->driver->io_mem_reserve) {
+		if (mem->bus.io_reserved) {
+			mem->bus.io_reserved = false;
+			bdev->driver->io_mem_free(bdev, mem);
+		}
+	}
+}
+
 int ttm_mem_reg_ioremap(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem,
 			void **virtual)
 {
-	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
-	unsigned long bus_offset;
-	unsigned long bus_size;
-	unsigned long bus_base;
 	int ret;
 	void *addr;
 
 	*virtual = NULL;
-	ret = ttm_bo_pci_offset(bdev, mem, &bus_base, &bus_offset, &bus_size);
-	if (ret || bus_size == 0)
+	ret = ttm_mem_io_reserve(bdev, mem);
+	if (ret)
 		return ret;
 
-	if (!(man->flags & TTM_MEMTYPE_FLAG_NEEDS_IOREMAP))
-		addr = (void *)(((u8 *) man->io_addr) + bus_offset);
-	else {
+	if (mem->bus.addr) {
+		addr = mem->bus.addr;
+	} else {
 		if (mem->placement & TTM_PL_FLAG_WC)
-			addr = ioremap_wc(bus_base + bus_offset, bus_size);
+			addr = ioremap_wc(mem->bus.base + mem->bus.offset, mem->bus.size);
 		else
-			addr = ioremap_nocache(bus_base + bus_offset, bus_size);
-		if (!addr)
+			addr = ioremap_nocache(mem->bus.base + mem->bus.offset, mem->bus.size);
+		if (!addr) {
+			ttm_mem_io_free(bdev, mem);
 			return -ENOMEM;
+		}
 	}
 	*virtual = addr;
 	return 0;
@@ -117,8 +149,9 @@ void ttm_mem_reg_iounmap(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem,
 
 	man = &bdev->man[mem->mem_type];
 
-	if (virtual && (man->flags & TTM_MEMTYPE_FLAG_NEEDS_IOREMAP))
+	if (virtual && (man->flags & TTM_MEMTYPE_FLAG_NEEDS_IOREMAP || mem->bus.addr == NULL))
 		iounmap(virtual);
+	ttm_mem_io_free(bdev, mem);
 }
 
 static int ttm_copy_io_page(void *dst, void *src, unsigned long page)
@@ -370,26 +403,23 @@ pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp)
 EXPORT_SYMBOL(ttm_io_prot);
 
 static int ttm_bo_ioremap(struct ttm_buffer_object *bo,
-			  unsigned long bus_base,
-			  unsigned long bus_offset,
-			  unsigned long bus_size,
+			  unsigned long offset,
+			  unsigned long size,
 			  struct ttm_bo_kmap_obj *map)
 {
-	struct ttm_bo_device *bdev = bo->bdev;
 	struct ttm_mem_reg *mem = &bo->mem;
-	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
 
-	if (!(man->flags & TTM_MEMTYPE_FLAG_NEEDS_IOREMAP)) {
+	if (bo->mem.bus.addr) {
 		map->bo_kmap_type = ttm_bo_map_premapped;
-		map->virtual = (void *)(((u8 *) man->io_addr) + bus_offset);
+		map->virtual = (void *)(((u8 *)bo->mem.bus.addr) + offset);
 	} else {
 		map->bo_kmap_type = ttm_bo_map_iomap;
 		if (mem->placement & TTM_PL_FLAG_WC)
-			map->virtual = ioremap_wc(bus_base + bus_offset,
-						  bus_size);
+			map->virtual = ioremap_wc(bo->mem.bus.base + bo->mem.bus.offset + offset,
+						  size);
 		else
-			map->virtual = ioremap_nocache(bus_base + bus_offset,
-						       bus_size);
+			map->virtual = ioremap_nocache(bo->mem.bus.base + bo->mem.bus.offset + offset,
+						       size);
 	}
 	return (!map->virtual) ? -ENOMEM : 0;
 }
@@ -442,13 +472,12 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
 		unsigned long start_page, unsigned long num_pages,
 		struct ttm_bo_kmap_obj *map)
 {
+	unsigned long offset, size;
 	int ret;
-	unsigned long bus_base;
-	unsigned long bus_offset;
-	unsigned long bus_size;
 
 	BUG_ON(!list_empty(&bo->swap));
 	map->virtual = NULL;
+	map->bo = bo;
 	if (num_pages > bo->num_pages)
 		return -EINVAL;
 	if (start_page > bo->num_pages)
@@ -457,16 +486,15 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
 	if (num_pages > 1 && !DRM_SUSER(DRM_CURPROC))
 		return -EPERM;
 #endif
-	ret = ttm_bo_pci_offset(bo->bdev, &bo->mem, &bus_base,
-				&bus_offset, &bus_size);
+	ret = ttm_mem_io_reserve(bo->bdev, &bo->mem);
 	if (ret)
 		return ret;
-	if (bus_size == 0) {
+	if (!bo->mem.bus.is_iomem) {
 		return ttm_bo_kmap_ttm(bo, start_page, num_pages, map);
 	} else {
-		bus_offset += start_page << PAGE_SHIFT;
-		bus_size = num_pages << PAGE_SHIFT;
-		return ttm_bo_ioremap(bo, bus_base, bus_offset, bus_size, map);
+		offset = start_page << PAGE_SHIFT;
+		size = num_pages << PAGE_SHIFT;
+		return ttm_bo_ioremap(bo, offset, size, map);
 	}
 }
 EXPORT_SYMBOL(ttm_bo_kmap);
@@ -478,6 +506,7 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
 	switch (map->bo_kmap_type) {
 	case ttm_bo_map_iomap:
 		iounmap(map->virtual);
+		ttm_mem_io_free(map->bo->bdev, &map->bo->mem);
 		break;
 	case ttm_bo_map_vmap:
 		vunmap(map->virtual);
@@ -495,35 +524,6 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
 }
 EXPORT_SYMBOL(ttm_bo_kunmap);
 
-int ttm_bo_pfn_prot(struct ttm_buffer_object *bo,
-		    unsigned long dst_offset,
-		    unsigned long *pfn, pgprot_t *prot)
-{
-	struct ttm_mem_reg *mem = &bo->mem;
-	struct ttm_bo_device *bdev = bo->bdev;
-	unsigned long bus_offset;
-	unsigned long bus_size;
-	unsigned long bus_base;
-	int ret;
-	ret = ttm_bo_pci_offset(bdev, mem, &bus_base, &bus_offset,
-			&bus_size);
-	if (ret)
-		return -EINVAL;
-	if (bus_size != 0)
-		*pfn = (bus_base + bus_offset + dst_offset) >> PAGE_SHIFT;
-	else
-		if (!bo->ttm)
-			return -EINVAL;
-		else
-			*pfn = page_to_pfn(ttm_tt_get_page(bo->ttm,
-							   dst_offset >>
-							   PAGE_SHIFT));
-	*prot = (mem->placement & TTM_PL_FLAG_CACHED) ?
-		PAGE_KERNEL : ttm_io_prot(mem->placement, PAGE_KERNEL);
-
-	return 0;
-}
-
 int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
 			      void *sync_obj,
 			      void *sync_obj_arg,

drivers/gpu/drm/ttm/ttm_bo_vm.c

@@ -74,9 +74,6 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	struct ttm_buffer_object *bo = (struct ttm_buffer_object *)
 	    vma->vm_private_data;
 	struct ttm_bo_device *bdev = bo->bdev;
-	unsigned long bus_base;
-	unsigned long bus_offset;
-	unsigned long bus_size;
 	unsigned long page_offset;
 	unsigned long page_last;
 	unsigned long pfn;
@@ -84,7 +81,6 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	struct page *page;
 	int ret;
 	int i;
-	bool is_iomem;
 	unsigned long address = (unsigned long)vmf->virtual_address;
 	int retval = VM_FAULT_NOPAGE;
 
@@ -101,8 +97,21 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 		return VM_FAULT_NOPAGE;
 	}
 
-	if (bdev->driver->fault_reserve_notify)
-		bdev->driver->fault_reserve_notify(bo);
+	if (bdev->driver->fault_reserve_notify) {
+		ret = bdev->driver->fault_reserve_notify(bo);
+		switch (ret) {
+		case 0:
+			break;
+		case -EBUSY:
+			set_need_resched();
+		case -ERESTARTSYS:
+			retval = VM_FAULT_NOPAGE;
+			goto out_unlock;
+		default:
+			retval = VM_FAULT_SIGBUS;
+			goto out_unlock;
+		}
+	}
 
 	/*
 	 * Wait for buffer data in transit, due to a pipelined
@@ -122,15 +131,12 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 		spin_unlock(&bo->lock);
 
 
-	ret = ttm_bo_pci_offset(bdev, &bo->mem, &bus_base, &bus_offset,
-				&bus_size);
-	if (unlikely(ret != 0)) {
+	ret = ttm_mem_io_reserve(bdev, &bo->mem);
+	if (ret) {
 		retval = VM_FAULT_SIGBUS;
 		goto out_unlock;
 	}
 
-	is_iomem = (bus_size != 0);
-
 	page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
 	    bo->vm_node->start - vma->vm_pgoff;
 	page_last = ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) +
@@ -154,8 +160,7 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	 * vma->vm_page_prot when the object changes caching policy, with
 	 * the correct locks held.
 	 */
-
-	if (is_iomem) {
+	if (bo->mem.bus.is_iomem) {
 		vma->vm_page_prot = ttm_io_prot(bo->mem.placement,
 						vma->vm_page_prot);
 	} else {
@@ -171,10 +176,8 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	 */
 
 	for (i = 0; i < TTM_BO_VM_NUM_PREFAULT; ++i) {
-
-		if (is_iomem)
-			pfn = ((bus_base + bus_offset) >> PAGE_SHIFT) +
-			    page_offset;
+		if (bo->mem.bus.is_iomem)
+			pfn = ((bo->mem.bus.base + bo->mem.bus.offset) >> PAGE_SHIFT) + page_offset;
 		else {
 			page = ttm_tt_get_page(ttm, page_offset);
 			if (unlikely(!page && i == 0)) {
@@ -198,7 +201,6 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 			retval =
 			    (ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
 			goto out_unlock;
-
 		}
 
 		address += PAGE_SIZE;
@@ -221,8 +223,7 @@ static void ttm_bo_vm_open(struct vm_area_struct *vma)
 
 static void ttm_bo_vm_close(struct vm_area_struct *vma)
 {
-	struct ttm_buffer_object *bo =
-	    (struct ttm_buffer_object *)vma->vm_private_data;
+	struct ttm_buffer_object *bo = (struct ttm_buffer_object *)vma->vm_private_data;
 
 	ttm_bo_unref(&bo);
 	vma->vm_private_data = NULL;

include/drm/ttm/ttm_bo_api.h

@@ -66,6 +66,26 @@ struct ttm_placement {
 	const uint32_t	*busy_placement;
 };
 
+/**
+ * struct ttm_bus_placement
+ *
+ * @addr:		mapped virtual address
+ * @base:		bus base address
+ * @is_iomem:		is this io memory ?
+ * @size:		size in byte
+ * @offset:		offset from the base address
+ *
+ * Structure indicating the bus placement of an object.
+ */
+struct ttm_bus_placement {
+	void		*addr;
+	unsigned long	base;
+	unsigned long	size;
+	unsigned long	offset;
+	bool		is_iomem;
+	bool		io_reserved;
+};
+
 
 /**
  * struct ttm_mem_reg
@@ -75,6 +95,7 @@ struct ttm_placement {
  * @num_pages: Actual size of memory region in pages.
  * @page_alignment: Page alignment.
  * @placement: Placement flags.
+ * @bus: Placement on io bus accessible to the CPU
  *
  * Structure indicating the placement and space resources used by a
  * buffer object.
@@ -87,6 +108,7 @@ struct ttm_mem_reg {
 	uint32_t page_alignment;
 	uint32_t mem_type;
 	uint32_t placement;
+	struct ttm_bus_placement bus;
 };
 
 /**
@@ -274,6 +296,7 @@ struct ttm_bo_kmap_obj {
 		ttm_bo_map_kmap         = 3,
 		ttm_bo_map_premapped    = 4 | TTM_BO_MAP_IOMEM_MASK,
 	} bo_kmap_type;
+	struct ttm_buffer_object *bo;
 };
 
 /**

include/drm/ttm/ttm_bo_driver.h

@@ -352,12 +352,21 @@ struct ttm_bo_driver {
 			    struct ttm_mem_reg *new_mem);
 	/* notify the driver we are taking a fault on this BO
 	 * and have reserved it */
-	void (*fault_reserve_notify)(struct ttm_buffer_object *bo);
+	int (*fault_reserve_notify)(struct ttm_buffer_object *bo);
 
 	/**
 	 * notify the driver that we're about to swap out this bo
 	 */
 	void (*swap_notify) (struct ttm_buffer_object *bo);
+
+	/**
+	 * Driver callback on when mapping io memory (for bo_move_memcpy
+	 * for instance). TTM will take care to call io_mem_free whenever
+	 * the mapping is not use anymore. io_mem_reserve & io_mem_free
+	 * are balanced.
+	 */
+	int (*io_mem_reserve)(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem);
+	void (*io_mem_free)(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem);
 };
 
 /**
@@ -685,6 +694,11 @@ extern int ttm_bo_pci_offset(struct ttm_bo_device *bdev,
 			     unsigned long *bus_offset,
 			     unsigned long *bus_size);
 
+extern int ttm_mem_io_reserve(struct ttm_bo_device *bdev,
+				struct ttm_mem_reg *mem);
+extern void ttm_mem_io_free(struct ttm_bo_device *bdev,
+				struct ttm_mem_reg *mem);
+
 extern void ttm_bo_global_release(struct ttm_global_reference *ref);
 extern int ttm_bo_global_init(struct ttm_global_reference *ref);