[RFC PATCH 17/42] drm/i915/lmem: support kernel mapping

[Matthew Auld <matthew.auld@intel.com>]

From: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>

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>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c               |  18 ++-
 drivers/gpu/drm/i915/intel_memory_region.h    |   3 +
 drivers/gpu/drm/i915/intel_region_lmem.c      |  24 ++++
 drivers/gpu/drm/i915/intel_region_lmem.h      |   5 +
 drivers/gpu/drm/i915/selftests/huge_pages.c   |   3 +-
 .../drm/i915/selftests/intel_memory_region.c  | 107 +++++++++++++++++-
 6 files changed, 148 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 33699b3dc395..3f319524beed 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2257,7 +2257,9 @@ __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj)
 		void *ptr;
 
 		ptr = page_mask_bits(obj->mm.mapping);
-		if (is_vmalloc_addr(ptr))
+		if (i915_gem_object_is_lmem(obj))
+			io_mapping_unmap(ptr);
+		else if (is_vmalloc_addr(ptr))
 			vunmap(ptr);
 		else
 			kunmap(kmap_to_page(ptr));
@@ -2625,7 +2627,7 @@ int __i915_gem_object_get_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;
@@ -2638,6 +2640,11 @@ 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)) {
+		/* XXX: we are ignoring the type here -- this is simply wc */
+		return i915_gem_object_lmem_io_map(obj, 0, obj->base.size);
+	}
+
 	/* A single page can always be kmapped */
 	if (n_pages == 1 && type == I915_MAP_WB)
 		return kmap(sg_page(sgt->sgl));
@@ -2683,7 +2690,8 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
 	void *ptr;
 	int ret;
 
-	if (unlikely(!i915_gem_object_has_struct_page(obj)))
+	if (unlikely(!i915_gem_object_has_struct_page(obj) &&
+		     !i915_gem_object_is_lmem(obj)))
 		return ERR_PTR(-ENXIO);
 
 	ret = mutex_lock_interruptible(&obj->mm.lock);
@@ -2715,7 +2723,9 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
 			goto err_unpin;
 		}
 
-		if (is_vmalloc_addr(ptr))
+		if (i915_gem_object_is_lmem(obj))
+			io_mapping_unmap(ptr);
+		else if (is_vmalloc_addr(ptr))
 			vunmap(ptr);
 		else
 			kunmap(kmap_to_page(ptr));
diff --git a/drivers/gpu/drm/i915/intel_memory_region.h b/drivers/gpu/drm/i915/intel_memory_region.h
index b1546afb0b6e..7754989ad165 100644
--- a/drivers/gpu/drm/i915/intel_memory_region.h
+++ b/drivers/gpu/drm/i915/intel_memory_region.h
@@ -115,6 +115,9 @@ void i915_memory_region_put_pages_buddy(struct drm_i915_gem_object *obj,
 
 void i915_gem_object_release_memory_region(struct drm_i915_gem_object *obj);
 
+unsigned long i915_gem_object_lmem_io_pfn(struct drm_i915_gem_object *obj,
+					  unsigned long n);
+
 struct intel_memory_region *
 intel_memory_region_create(struct drm_i915_private *i915,
 			   resource_size_t start,
diff --git a/drivers/gpu/drm/i915/intel_region_lmem.c b/drivers/gpu/drm/i915/intel_region_lmem.c
index b398becb2733..c8bee0c18c88 100644
--- a/drivers/gpu/drm/i915/intel_region_lmem.c
+++ b/drivers/gpu/drm/i915/intel_region_lmem.c
@@ -65,6 +65,30 @@ static const struct intel_memory_region_ops region_lmem_ops = {
 	.object_create = region_lmem_object_create,
 };
 
+/* 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_atomic_wc(&obj->memory_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(!(obj->flags & I915_BO_ALLOC_CONTIGUOUS));
+
+	offset = i915_gem_object_get_dma_address(obj, n);
+
+	return io_mapping_map_wc(&obj->memory_region->iomap, offset, size);
+}
+
 unsigned long i915_gem_object_lmem_io_pfn(struct drm_i915_gem_object *obj,
 					  unsigned long n)
 {
diff --git a/drivers/gpu/drm/i915/intel_region_lmem.h b/drivers/gpu/drm/i915/intel_region_lmem.h
index 1aa24bd28690..a76b77b69e71 100644
--- a/drivers/gpu/drm/i915/intel_region_lmem.h
+++ b/drivers/gpu/drm/i915/intel_region_lmem.h
@@ -28,6 +28,11 @@
 unsigned long i915_gem_object_lmem_io_pfn(struct drm_i915_gem_object *obj,
 					  unsigned long n);
 
+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);
+
 bool i915_gem_object_is_lmem(struct drm_i915_gem_object *obj);
 
 struct drm_i915_gem_object *
diff --git a/drivers/gpu/drm/i915/selftests/huge_pages.c b/drivers/gpu/drm/i915/selftests/huge_pages.c
index f4283d41c13f..103362f8c553 100644
--- a/drivers/gpu/drm/i915/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/selftests/huge_pages.c
@@ -1144,8 +1144,7 @@ static int __cpu_check_lmem(struct drm_i915_gem_object *obj, u32 dword, u32 val)
 		u32 __iomem *base;
 		u32 read_val;
 
-		base = (void __force *)io_mapping_map_atomic_wc(&obj->memory_region->iomap,
-								i915_gem_object_get_dma_address(obj, n));
+		base = i915_gem_object_lmem_io_map_page(obj, n);
 
 		read_val = ioread32(base + dword);
 		io_mapping_unmap_atomic(base);
diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
index 2c07d8d219e5..ad8d2eeacf53 100644
--- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
@@ -28,6 +28,9 @@
 #include "mock_context.h"
 #include "mock_drm.h"
 
+typedef int (*cpu_check_fn_t)(struct drm_i915_gem_object *obj,
+			      u32 __iomem *base, u32 dword, u32 val);
+
 static void close_objects(struct list_head *objects)
 {
 	struct drm_i915_gem_object *obj, *on;
@@ -487,7 +490,9 @@ static int igt_gpu_write(struct i915_vma *vma,
 	return err;
 }
 
-static int igt_cpu_check(struct drm_i915_gem_object *obj, u32 dword, u32 val)
+static int igt_cpu_check(struct drm_i915_gem_object *obj,
+			 u32 __iomem *base,
+			 u32 dword, u32 val)
 {
 	unsigned long n;
 	int err;
@@ -504,8 +509,7 @@ static int igt_cpu_check(struct drm_i915_gem_object *obj, u32 dword, u32 val)
 		u32 __iomem *base;
 		u32 read_val;
 
-		base = (void __force *) io_mapping_map_atomic_wc(&obj->memory_region->iomap,
-								 i915_gem_object_get_dma_address(obj, n));
+		base = i915_gem_object_lmem_io_map_page(obj, n);
 
 		read_val = ioread32(base + dword);
 		io_mapping_unmap_atomic(base);
@@ -523,11 +527,13 @@ static int igt_cpu_check(struct drm_i915_gem_object *obj, u32 dword, u32 val)
 
 static int igt_gpu_fill(struct i915_gem_context *ctx,
 			struct drm_i915_gem_object *obj,
-			u32 val)
+			cpu_check_fn_t cpu_check,
+			u32 __iomem *base)
 {
 	struct drm_i915_private *i915 = ctx->i915;
 	struct i915_address_space *vm = ctx->ppgtt ? &ctx->ppgtt->vm : &i915->ggtt.vm;
 	struct i915_vma *vma;
+	struct rnd_state prng;
 	u32 dword;
 	int err;
 
@@ -541,12 +547,14 @@ static int igt_gpu_fill(struct i915_gem_context *ctx,
 		return err;
 	}
 
+	prandom_seed_state(&prng, i915_selftest.random_seed);
 	for (dword = 0; dword < PAGE_SIZE / sizeof(u32); ++dword) {
+		u32 val = prandom_u32_state(&prng);
 		err = igt_gpu_write(vma, ctx, i915->engine[RCS], dword, val);
 		if (err)
 			break;
 
-		err = igt_cpu_check(obj, dword, val);
+		err = cpu_check(obj, base, dword, val);
 		if (err)
 			break;
 	}
@@ -645,7 +653,7 @@ static int igt_lmem_write_gpu(void *arg)
 	if (err)
 		goto out_put;
 
-	err = igt_gpu_fill(ctx, obj, 0xdeadbeaf);
+	err = igt_gpu_fill(ctx, obj, igt_cpu_check, NULL);
 	if (err) {
 		pr_err("igt_gpu_fill failed(%d)\n", err);
 		goto out_unpin;
@@ -659,6 +667,92 @@ static int igt_lmem_write_gpu(void *arg)
 	return err;
 }
 
+static int igt_lmem_cpu_check(struct drm_i915_gem_object *obj,
+			      u32 __iomem *base, u32 dword, u32 val)
+{
+	u32 read_val;
+	int err;
+
+	err = i915_gem_object_wait(obj,
+				   I915_WAIT_INTERRUPTIBLE |
+				   I915_WAIT_LOCKED,
+				   MAX_SCHEDULE_TIMEOUT);
+	if (err)
+		return err;
+
+	err = i915_gem_object_pin_pages(obj);
+	if (err)
+		return err;
+
+	read_val = ioread32(base + dword);
+        if (read_val != val) {
+		pr_err("base[%u]=0x%x, val=0x%x\n",
+		       dword, read_val, val);
+		return -EINVAL;
+	}
+
+	i915_gem_object_unpin_pages(obj);
+	return 0;
+}
+
+static int igt_lmem_write_cpu(void *arg)
+{
+	struct i915_gem_context *ctx = arg;
+	struct drm_i915_private *i915 = ctx->i915;
+	struct drm_i915_gem_object *obj;
+	struct rnd_state prng;
+	u32 __iomem *vaddr;
+	u32 dword;
+	int ret = 0;
+
+	obj = i915_gem_object_create_lmem(i915, PAGE_SIZE, I915_BO_ALLOC_CONTIGUOUS);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	ret = i915_gem_object_pin_pages(obj);
+	if (ret)
+		goto out_put;
+
+	vaddr = i915_gem_object_pin_map(obj, I915_MAP_WC);
+	if (IS_ERR(vaddr)) {
+		pr_err("Failed to iomap lmembar; err=%d\n", (int)PTR_ERR(vaddr));
+		ret = PTR_ERR(vaddr);
+		goto out_unpin;
+	}
+
+	/* gpu write/cpu read */
+	ret = igt_gpu_fill(ctx, obj, igt_lmem_cpu_check, vaddr);
+	if (ret) {
+		pr_err("igt_gpu_fill failed(%d)\n", ret);
+		goto out_unpin;
+	}
+
+	/* cpu write/cpu read */
+	prandom_seed_state(&prng, i915_selftest.random_seed);
+	for (dword = 0; dword < PAGE_SIZE / sizeof(u32); ++dword) {
+		u32 read_val;
+		u32 val = prandom_u32_state(&prng);
+
+		iowrite32(val, vaddr + dword);
+		wmb();
+
+		read_val = ioread32(vaddr + dword);
+		if (read_val != val) {
+			pr_err("base[%u]=%u, val=%u\n", dword, read_val, val);
+			ret = -EINVAL;
+			break;
+		}
+	}
+
+	i915_gem_object_unpin_map(obj);
+
+out_unpin:
+	i915_gem_object_unpin_pages(obj);
+out_put:
+	i915_gem_object_put(obj);
+	return ret;
+}
+
 static int igt_lmem_pages_migrate(void *arg)
 {
 	struct i915_gem_context *ctx = arg;
@@ -776,6 +870,7 @@ int intel_memory_region_live_selftests(struct drm_i915_private *i915)
 		SUBTEST(igt_smem_create_migrate),
 		SUBTEST(igt_lmem_create_migrate),
 		SUBTEST(igt_lmem_write_gpu),
+		SUBTEST(igt_lmem_write_cpu),
 		SUBTEST(igt_lmem_pages_migrate),
 	};
 	struct i915_gem_context *ctx;
-- 
2.20.1

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