drm/i915/gem: Support discontiguous lmem object maps

Create a vmap for discontinguous lmem objects to support
i915_gem_object_pin_map().

v2: Offset io address by region.start for fake-lmem

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200102204215.1519103-1-chris@chris-wilson.co.uk

4 files changed, 64 insertions, 104 deletions

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
index 520cc9cac471..70543c83df06 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
@@ -16,46 +16,6 @@ const struct drm_i915_gem_object_ops i915_gem_lmem_obj_ops = {
 	.release = i915_gem_object_release_memory_region,
 };
 
-/* XXX: Time to vfunc your life up? */
-void __iomem *
-i915_gem_object_lmem_io_map_page(struct drm_i915_gem_object *obj,
-				 unsigned long n)
-{
-	resource_size_t offset;
-
-	offset = i915_gem_object_get_dma_address(obj, n);
-	offset -= obj->mm.region->region.start;
-
-	return io_mapping_map_wc(&obj->mm.region->iomap, offset, PAGE_SIZE);
-}
-
-void __iomem *
-i915_gem_object_lmem_io_map_page_atomic(struct drm_i915_gem_object *obj,
-					unsigned long n)
-{
-	resource_size_t offset;
-
-	offset = i915_gem_object_get_dma_address(obj, n);
-	offset -= obj->mm.region->region.start;
-
-	return io_mapping_map_atomic_wc(&obj->mm.region->iomap, offset);
-}
-
-void __iomem *
-i915_gem_object_lmem_io_map(struct drm_i915_gem_object *obj,
-			    unsigned long n,
-			    unsigned long size)
-{
-	resource_size_t offset;
-
-	GEM_BUG_ON(!i915_gem_object_is_contiguous(obj));
-
-	offset = i915_gem_object_get_dma_address(obj, n);
-	offset -= obj->mm.region->region.start;
-
-	return io_mapping_map_wc(&obj->mm.region->iomap, offset, size);
-}
-
 bool i915_gem_object_is_lmem(struct drm_i915_gem_object *obj)
 {
 	return obj->ops == &i915_gem_lmem_obj_ops;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.h b/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
index 7c176b8b7d2f..fc3f15580fe3 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
@@ -14,14 +14,6 @@ struct intel_memory_region;
 
 extern const struct drm_i915_gem_object_ops i915_gem_lmem_obj_ops;
 
-void __iomem *i915_gem_object_lmem_io_map(struct drm_i915_gem_object *obj,
-					  unsigned long n, unsigned long size);
-void __iomem *i915_gem_object_lmem_io_map_page(struct drm_i915_gem_object *obj,
-					       unsigned long n);
-void __iomem *
-i915_gem_object_lmem_io_map_page_atomic(struct drm_i915_gem_object *obj,
-					unsigned long n);
-
 bool i915_gem_object_is_lmem(struct drm_i915_gem_object *obj);
 
 struct drm_i915_gem_object *
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 75197ca696a8..54aca5c9101e 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -158,9 +158,7 @@ static void __i915_gem_object_reset_page_iter(struct drm_i915_gem_object *obj)
 
 static void unmap_object(struct drm_i915_gem_object *obj, void *ptr)
 {
-	if (i915_gem_object_is_lmem(obj))
-		io_mapping_unmap((void __force __iomem *)ptr);
-	else if (is_vmalloc_addr(ptr))
+	if (is_vmalloc_addr(ptr))
 		vunmap(ptr);
 	else
 		kunmap(kmap_to_page(ptr));
@@ -236,46 +234,44 @@ unlock:
 	return err;
 }
 
+static inline pte_t iomap_pte(resource_size_t base,
+			      dma_addr_t offset,
+			      pgprot_t prot)
+{
+	return pte_mkspecial(pfn_pte((base + offset) >> PAGE_SHIFT, prot));
+}
+
 /* The 'mapping' part of i915_gem_object_pin_map() below */
 static void *i915_gem_object_map(struct drm_i915_gem_object *obj,
 				 enum i915_map_type type)
 {
-	unsigned long n_pages = obj->base.size >> PAGE_SHIFT;
+	unsigned long n_pte = obj->base.size >> PAGE_SHIFT;
 	struct sg_table *sgt = obj->mm.pages;
-	struct sgt_iter sgt_iter;
-	struct page *page;
-	struct page *stack_pages[32];
-	struct page **pages = stack_pages;
-	unsigned long i = 0;
+	pte_t *stack[32], **mem;
+	struct vm_struct *area;
 	pgprot_t pgprot;
-	void *addr;
 
-	if (i915_gem_object_is_lmem(obj)) {
-		void __iomem *io;
-
-		if (type != I915_MAP_WC)
-			return NULL;
-
-		io = i915_gem_object_lmem_io_map(obj, 0, obj->base.size);
-		return (void __force *)io;
-	}
+	if (!i915_gem_object_has_struct_page(obj) && type != I915_MAP_WC)
+		return NULL;
 
 	/* A single page can always be kmapped */
-	if (n_pages == 1 && type == I915_MAP_WB)
+	if (n_pte == 1 && type == I915_MAP_WB)
 		return kmap(sg_page(sgt->sgl));
 
-	if (n_pages > ARRAY_SIZE(stack_pages)) {
+	mem = stack;
+	if (n_pte > ARRAY_SIZE(stack)) {
 		/* Too big for stack -- allocate temporary array instead */
-		pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
-		if (!pages)
+		mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL);
+		if (!mem)
 			return NULL;
 	}
 
-	for_each_sgt_page(page, sgt_iter, sgt)
-		pages[i++] = page;
-
-	/* Check that we have the expected number of pages */
-	GEM_BUG_ON(i != n_pages);
+	area = alloc_vm_area(obj->base.size, mem);
+	if (!area) {
+		if (mem != stack)
+			kvfree(mem);
+		return NULL;
+	}
 
 	switch (type) {
 	default:
@@ -288,12 +284,31 @@ static void *i915_gem_object_map(struct drm_i915_gem_object *obj,
 		pgprot = pgprot_writecombine(PAGE_KERNEL_IO);
 		break;
 	}
-	addr = vmap(pages, n_pages, 0, pgprot);
 
-	if (pages != stack_pages)
-		kvfree(pages);
+	if (i915_gem_object_has_struct_page(obj)) {
+		struct sgt_iter iter;
+		struct page *page;
+		pte_t **ptes = mem;
+
+		for_each_sgt_page(page, iter, sgt)
+			**ptes++ = mk_pte(page, pgprot);
+	} else {
+		resource_size_t iomap;
+		struct sgt_iter iter;
+		pte_t **ptes = mem;
+		dma_addr_t addr;
+
+		iomap = obj->mm.region->iomap.base;
+		iomap -= obj->mm.region->region.start;
+
+		for_each_sgt_daddr(addr, iter, sgt)
+			**ptes++ = iomap_pte(iomap, addr, pgprot);
+	}
+
+	if (mem != stack)
+		kvfree(mem);
 
-	return addr;
+	return area->addr;
 }
 
 /* get, pin, and map the pages of the object into kernel space */
diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
index 2479395c1873..249a4d24d678 100644
--- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
@@ -1017,38 +1017,33 @@ __cpu_check_shmem(struct drm_i915_gem_object *obj, u32 dword, u32 val)
 	return err;
 }
 
-static int __cpu_check_lmem(struct drm_i915_gem_object *obj, u32 dword, u32 val)
+static int __cpu_check_vmap(struct drm_i915_gem_object *obj, u32 dword, u32 val)
 {
-	unsigned long n;
+	unsigned long n = obj->base.size >> PAGE_SHIFT;
+	u32 *ptr;
 	int err;
 
-	i915_gem_object_lock(obj);
-	err = i915_gem_object_set_to_wc_domain(obj, false);
-	i915_gem_object_unlock(obj);
-	if (err)
-		return err;
-
-	err = i915_gem_object_pin_pages(obj);
+	err = i915_gem_object_wait(obj, 0, MAX_SCHEDULE_TIMEOUT);
 	if (err)
 		return err;
 
-	for (n = 0; n < obj->base.size >> PAGE_SHIFT; ++n) {
-		u32 __iomem *base;
-		u32 read_val;
-
-		base = i915_gem_object_lmem_io_map_page_atomic(obj, n);
+	ptr = i915_gem_object_pin_map(obj, I915_MAP_WC);
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
 
-		read_val = ioread32(base + dword);
-		io_mapping_unmap_atomic(base);
-		if (read_val != val) {
-			pr_err("n=%lu base[%u]=%u, val=%u\n",
-			       n, dword, read_val, val);
+	ptr += dword;
+	while (n--) {
+		if (*ptr != val) {
+			pr_err("base[%u]=%08x, val=%08x\n",
+			       dword, *ptr, val);
 			err = -EINVAL;
 			break;
 		}
+
+		ptr += PAGE_SIZE / sizeof(*ptr);
 	}
 
-	i915_gem_object_unpin_pages(obj);
+	i915_gem_object_unpin_map(obj);
 	return err;
 }
 
@@ -1056,10 +1051,8 @@ static int cpu_check(struct drm_i915_gem_object *obj, u32 dword, u32 val)
 {
 	if (i915_gem_object_has_struct_page(obj))
 		return __cpu_check_shmem(obj, dword, val);
-	else if (i915_gem_object_is_lmem(obj))
-		return __cpu_check_lmem(obj, dword, val);
-
-	return -ENODEV;
+	else
+		return __cpu_check_vmap(obj, dword, val);
 }
 
 static int __igt_write_huge(struct intel_context *ce,