drm/i915/lmem: support kernel mapping

We can create LMEM objects, but we also need to support mapping them
into kernel space for internal use.
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Steve Hampson <steven.t.hampson@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191025153728.23689-3-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gem/i915_gem_lmem.c

@@ -9,11 +9,50 @@
 #include "i915_drv.h"
 
 const struct drm_i915_gem_object_ops i915_gem_lmem_obj_ops = {
+	.flags = I915_GEM_OBJECT_HAS_IOMEM,
+
 	.get_pages = i915_gem_object_get_pages_buddy,
 	.put_pages = i915_gem_object_put_pages_buddy,
 	.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);
+
+	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);
+
+	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);
+
+	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;

drivers/gpu/drm/i915/gem/i915_gem_lmem.h

@@ -14,6 +14,14 @@ 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 *

drivers/gpu/drm/i915/gem/i915_gem_object_types.h

@@ -31,10 +31,11 @@ struct i915_lut_handle {
 struct drm_i915_gem_object_ops {
 	unsigned int flags;
 #define I915_GEM_OBJECT_HAS_STRUCT_PAGE	BIT(0)
-#define I915_GEM_OBJECT_IS_SHRINKABLE	BIT(1)
-#define I915_GEM_OBJECT_IS_PROXY	BIT(2)
-#define I915_GEM_OBJECT_NO_GGTT		BIT(3)
-#define I915_GEM_OBJECT_ASYNC_CANCEL	BIT(4)
+#define I915_GEM_OBJECT_HAS_IOMEM	BIT(1)
+#define I915_GEM_OBJECT_IS_SHRINKABLE	BIT(2)
+#define I915_GEM_OBJECT_IS_PROXY	BIT(3)
+#define I915_GEM_OBJECT_NO_GGTT		BIT(4)
+#define I915_GEM_OBJECT_ASYNC_CANCEL	BIT(5)
 
 	/* Interface between the GEM object and its backing storage.
 	 * get_pages() is called once prior to the use of the associated set

drivers/gpu/drm/i915/gem/i915_gem_pages.c

@@ -7,6 +7,7 @@
 #include "i915_drv.h"
 #include "i915_gem_object.h"
 #include "i915_scatterlist.h"
+#include "i915_gem_lmem.h"
 
 void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
 				 struct sg_table *pages,
@@ -154,6 +155,16 @@ static void __i915_gem_object_reset_page_iter(struct drm_i915_gem_object *obj)
 	rcu_read_unlock();
 }
 
+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))
+		vunmap(ptr);
+	else
+		kunmap(kmap_to_page(ptr));
+}
+
 struct sg_table *
 __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj)
 {
@@ -169,14 +180,7 @@ __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj)
 	i915_gem_object_make_unshrinkable(obj);
 
 	if (obj->mm.mapping) {
-		void *ptr;
-
-		ptr = page_mask_bits(obj->mm.mapping);
-		if (is_vmalloc_addr(ptr))
-			vunmap(ptr);
-		else
-			kunmap(kmap_to_page(ptr));
-
+		unmap_object(obj, page_mask_bits(obj->mm.mapping));
 		obj->mm.mapping = NULL;
 	}
 
@@ -231,7 +235,7 @@ int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj,
 }
 
 /* The 'mapping' part of i915_gem_object_pin_map() below */
-static void *i915_gem_object_map(const struct drm_i915_gem_object *obj,
+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;
@@ -244,6 +248,16 @@ static void *i915_gem_object_map(const struct drm_i915_gem_object *obj,
 	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;
+	}
+
 	/* A single page can always be kmapped */
 	if (n_pages == 1 && type == I915_MAP_WB)
 		return kmap(sg_page(sgt->sgl));
@@ -285,11 +299,13 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
 			      enum i915_map_type type)
 {
 	enum i915_map_type has_type;
+	unsigned int flags;
 	bool pinned;
 	void *ptr;
 	int err;
 
-	if (unlikely(!i915_gem_object_has_struct_page(obj)))
+	flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE | I915_GEM_OBJECT_HAS_IOMEM;
+	if (!i915_gem_object_type_has(obj, flags))
 		return ERR_PTR(-ENXIO);
 
 	err = mutex_lock_interruptible(&obj->mm.lock);
@@ -321,10 +337,7 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
 			goto err_unpin;
 		}
 
-		if (is_vmalloc_addr(ptr))
-			vunmap(ptr);
-		else
-			kunmap(kmap_to_page(ptr));
+		unmap_object(obj, ptr);
 
 		ptr = obj->mm.mapping = NULL;
 	}

drivers/gpu/drm/i915/selftests/intel_memory_region.c

@@ -13,8 +13,10 @@
 
 #include "gem/i915_gem_lmem.h"
 #include "gem/i915_gem_region.h"
+#include "gem/i915_gem_object_blt.h"
 #include "gem/selftests/mock_context.h"
 #include "gt/intel_gt.h"
+#include "selftests/igt_flush_test.h"
 #include "selftests/i915_random.h"
 
 static void close_objects(struct intel_memory_region *mem,
@@ -275,6 +277,116 @@ static int igt_lmem_create(void *arg)
 	return err;
 }
 
+static int igt_lmem_write_cpu(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct drm_i915_gem_object *obj;
+	I915_RND_STATE(prng);
+	IGT_TIMEOUT(end_time);
+	u32 bytes[] = {
+		0, /* rng placeholder */
+		sizeof(u32),
+		sizeof(u64),
+		64, /* cl */
+		PAGE_SIZE,
+		PAGE_SIZE - sizeof(u32),
+		PAGE_SIZE - sizeof(u64),
+		PAGE_SIZE - 64,
+	};
+	u32 *vaddr;
+	u32 sz;
+	u32 i;
+	int *order;
+	int count;
+	int err;
+
+	if (!HAS_ENGINE(i915, BCS0))
+		return 0;
+
+	sz = round_up(prandom_u32_state(&prng) % SZ_32M, PAGE_SIZE);
+	sz = max_t(u32, 2 * PAGE_SIZE, sz);
+
+	obj = i915_gem_object_create_lmem(i915, sz, I915_BO_ALLOC_CONTIGUOUS);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	vaddr = i915_gem_object_pin_map(obj, I915_MAP_WC);
+	if (IS_ERR(vaddr)) {
+		err = PTR_ERR(vaddr);
+		goto out_put;
+	}
+
+	/* Put the pages into a known state -- from the gpu for added fun */
+	err = i915_gem_object_fill_blt(obj, i915->engine[BCS0]->kernel_context,
+				       0xdeadbeaf);
+	if (err)
+		goto out_unpin;
+
+	i915_gem_object_lock(obj);
+	err = i915_gem_object_set_to_wc_domain(obj, true);
+	i915_gem_object_unlock(obj);
+	if (err)
+		goto out_unpin;
+
+	count = ARRAY_SIZE(bytes);
+	order = i915_random_order(count * count, &prng);
+	if (!order) {
+		err = -ENOMEM;
+		goto out_unpin;
+	}
+
+	/* We want to throw in a random width/align */
+	bytes[0] = igt_random_offset(&prng, 0, PAGE_SIZE, sizeof(u32),
+				     sizeof(u32));
+
+	i = 0;
+	do {
+		u32 offset;
+		u32 align;
+		u32 dword;
+		u32 size;
+		u32 val;
+
+		size = bytes[order[i] % count];
+		i = (i + 1) % (count * count);
+
+		align = bytes[order[i] % count];
+		i = (i + 1) % (count * count);
+
+		align = max_t(u32, sizeof(u32), rounddown_pow_of_two(align));
+
+		offset = igt_random_offset(&prng, 0, obj->base.size,
+					   size, align);
+
+		val = prandom_u32_state(&prng);
+		memset32(vaddr + offset / sizeof(u32), val ^ 0xdeadbeaf,
+			 size / sizeof(u32));
+
+		/*
+		 * Sample random dw -- don't waste precious time reading every
+		 * single dw.
+		 */
+		dword = igt_random_offset(&prng, offset,
+					  offset + size,
+					  sizeof(u32), sizeof(u32));
+		dword /= sizeof(u32);
+		if (vaddr[dword] != (val ^ 0xdeadbeaf)) {
+			pr_err("%s vaddr[%u]=%u, val=%u, size=%u, align=%u, offset=%u\n",
+			       __func__, dword, vaddr[dword], val ^ 0xdeadbeaf,
+			       size, align, offset);
+			err = -EINVAL;
+			break;
+		}
+	} while (!__igt_timeout(end_time, NULL));
+
+out_unpin:
+	i915_gem_object_unpin_map(obj);
+out_put:
+	i915_gem_object_put(obj);
+
+	return err;
+}
+
 int intel_memory_region_mock_selftests(void)
 {
 	static const struct i915_subtest tests[] = {
@@ -308,6 +420,7 @@ int intel_memory_region_live_selftests(struct drm_i915_private *i915)
 {
 	static const struct i915_subtest tests[] = {
 		SUBTEST(igt_lmem_create),
+		SUBTEST(igt_lmem_write_cpu),
 	};
 
 	if (!HAS_LMEM(i915)) {