[PATCH 22/22] HAX drm/i915: add the fake lmem region

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

Intended for upstream testing so that we can still exercise the LMEM
plumbing and !HAS_MAPPABLE_APERTURE paths. Smoke tested on Skull Canyon
device. This works by allocating an intel_memory_region for a reserved
portion of system memory, which we treat like LMEM. For the LMEMBAR we
steal the aperture and 1:1 it map to the stolen region.

To enable simply set i915_fake_lmem_start= on the kernel cmdline with the
start of reserved region(see memmap=). The size of the region we can
use is determined by the size of the mappable aperture, so the size of
reserved region should be >= mappable_end.

eg. memmap=2G$16G i915_fake_lmem_start=0x400000000

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
---
 arch/x86/kernel/early-quirks.c             | 26 +++++++
 drivers/gpu/drm/i915/gem/i915_gem_lmem.c   |  3 +
 drivers/gpu/drm/i915/i915_drv.c            |  8 ++
 drivers/gpu/drm/i915/i915_gem_gtt.c        |  3 +
 drivers/gpu/drm/i915/intel_memory_region.h |  6 ++
 drivers/gpu/drm/i915/intel_region_lmem.c   | 90 ++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_region_lmem.h   |  5 ++
 include/drm/i915_drm.h                     |  3 +
 8 files changed, 144 insertions(+)

diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
index 6f6b1d04dadf..9b04655e3926 100644
--- a/arch/x86/kernel/early-quirks.c
+++ b/arch/x86/kernel/early-quirks.c
@@ -603,6 +603,32 @@ static void __init intel_graphics_quirks(int num, int slot, int func)
 	}
 }
 
+struct resource intel_graphics_fake_lmem_res __ro_after_init = DEFINE_RES_MEM(0, 0);
+EXPORT_SYMBOL(intel_graphics_fake_lmem_res);
+
+static int __init early_i915_fake_lmem_init(char *s)
+{
+	u64 start;
+	int ret;
+
+	if (*s == '=')
+		s++;
+
+	ret = kstrtoull(s, 16, &start);
+	if (ret)
+		return ret;
+
+	intel_graphics_fake_lmem_res.start = start;
+	intel_graphics_fake_lmem_res.end = SZ_2G; /* Placeholder; depends on aperture size */
+
+	printk(KERN_INFO "Intel graphics fake LMEM starts at %pa\n",
+	       &intel_graphics_fake_lmem_res.start);
+
+	return 0;
+}
+
+early_param("i915_fake_lmem_start", early_i915_fake_lmem_init);
+
 static void __init force_disable_hpet(int num, int slot, int func)
 {
 #ifdef CONFIG_HPET_TIMER
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
index d7ec74ed5b88..c5e75c2f2511 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
@@ -23,6 +23,7 @@ void __iomem *i915_gem_object_lmem_io_map_page(struct drm_i915_gem_object *obj,
 	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);
 }
@@ -33,6 +34,7 @@ void __iomem *i915_gem_object_lmem_io_map_page_atomic(struct drm_i915_gem_object
 	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);
 }
@@ -46,6 +48,7 @@ void __iomem *i915_gem_object_lmem_io_map(struct drm_i915_gem_object *obj,
 	GEM_BUG_ON(!(obj->flags & I915_BO_ALLOC_CONTIGUOUS));
 
 	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);
 }
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 91aae56b4280..98fa1932c4aa 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1546,6 +1546,14 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (!i915_modparams.nuclear_pageflip && match_info->gen < 5)
 		dev_priv->drm.driver_features &= ~DRIVER_ATOMIC;
 
+	/* Check if we support fake LMEM -- enable for live selftests */
+	if (INTEL_GEN(dev_priv) >= 9 && i915_selftest.live &&
+	    intel_graphics_fake_lmem_res.start) {
+		mkwrite_device_info(dev_priv)->memory_regions =
+			REGION_SMEM | REGION_LMEM;
+		GEM_BUG_ON(!HAS_LMEM(dev_priv));
+	}
+
 	ret = pci_enable_device(pdev);
 	if (ret)
 		goto out_fini;
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 29f9c43b2c68..02d2a6266b8c 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2778,6 +2778,9 @@ int i915_gem_init_memory_regions(struct drm_i915_private *i915)
 		case INTEL_STOLEN:
 			mem = i915_gem_stolen_setup(i915);
 			break;
+		case INTEL_LMEM:
+			mem = intel_setup_fake_lmem(i915);
+			break;
 		}
 
 		if (IS_ERR(mem)) {
diff --git a/drivers/gpu/drm/i915/intel_memory_region.h b/drivers/gpu/drm/i915/intel_memory_region.h
index 9ef2ec760a4b..61f0da075805 100644
--- a/drivers/gpu/drm/i915/intel_memory_region.h
+++ b/drivers/gpu/drm/i915/intel_memory_region.h
@@ -9,6 +9,7 @@
 #include <linux/ioport.h>
 #include <linux/mutex.h>
 #include <linux/io-mapping.h>
+#include <drm/drm_mm.h>
 
 #include "i915_buddy.h"
 
@@ -70,6 +71,9 @@ struct intel_memory_region {
 	struct io_mapping iomap;
 	struct resource region;
 
+	/* For faking for lmem */
+	struct drm_mm_node fake_mappable;
+
 	struct i915_buddy_mm mm;
 	struct mutex mm_lock;
 
@@ -80,6 +84,8 @@ struct intel_memory_region {
 	unsigned int instance;
 	unsigned int id;
 
+	dma_addr_t remap_addr;
+
 	/* Protects access to objects and purgeable */
 	struct mutex obj_lock;
 	struct list_head objects;
diff --git a/drivers/gpu/drm/i915/intel_region_lmem.c b/drivers/gpu/drm/i915/intel_region_lmem.c
index 051069664074..935b8f19653c 100644
--- a/drivers/gpu/drm/i915/intel_region_lmem.c
+++ b/drivers/gpu/drm/i915/intel_region_lmem.c
@@ -36,9 +36,62 @@ lmem_create_object(struct intel_memory_region *mem,
 	return obj;
 }
 
+static int init_fake_lmem_bar(struct intel_memory_region *mem)
+{
+	struct drm_i915_private *i915 = mem->i915;
+	struct i915_ggtt *ggtt = &i915->ggtt;
+	unsigned long n;
+	int ret;
+
+	/* We want to 1:1 map the mappable aperture to our reserved region */
+
+	mem->fake_mappable.start = 0;
+	mem->fake_mappable.size = resource_size(&mem->region);
+	mem->fake_mappable.color = I915_COLOR_UNEVICTABLE;
+
+	ret = drm_mm_reserve_node(&ggtt->vm.mm, &mem->fake_mappable);
+	if (ret)
+		return ret;
+
+	mem->remap_addr = dma_map_resource(&i915->drm.pdev->dev,
+					   mem->region.start,
+					   mem->fake_mappable.size,
+					   PCI_DMA_BIDIRECTIONAL,
+					   DMA_ATTR_FORCE_CONTIGUOUS);
+	if (dma_mapping_error(&i915->drm.pdev->dev, mem->remap_addr)) {
+		drm_mm_remove_node(&mem->fake_mappable);
+		return -EINVAL;
+	}
+
+	for (n = 0; n < mem->fake_mappable.size >> PAGE_SHIFT; ++n) {
+		ggtt->vm.insert_page(&ggtt->vm,
+				     mem->remap_addr + (n << PAGE_SHIFT),
+				     n << PAGE_SHIFT,
+				     I915_CACHE_NONE, 0);
+	}
+
+	mem->region = (struct resource)DEFINE_RES_MEM(mem->remap_addr,
+						      mem->fake_mappable.size);
+
+	return 0;
+}
+
+static void release_fake_lmem_bar(struct intel_memory_region *mem)
+{
+	if (drm_mm_node_allocated(&mem->fake_mappable))
+		drm_mm_remove_node(&mem->fake_mappable);
+
+	dma_unmap_resource(&mem->i915->drm.pdev->dev,
+			   mem->remap_addr,
+			   mem->fake_mappable.size,
+			   PCI_DMA_BIDIRECTIONAL,
+			   DMA_ATTR_FORCE_CONTIGUOUS);
+}
+
 static void
 region_lmem_release(struct intel_memory_region *mem)
 {
+	release_fake_lmem_bar(mem);
 	io_mapping_fini(&mem->iomap);
 	intel_memory_region_release_buddy(mem);
 }
@@ -48,6 +101,11 @@ region_lmem_init(struct intel_memory_region *mem)
 {
 	int ret;
 
+	if (intel_graphics_fake_lmem_res.start) {
+		ret = init_fake_lmem_bar(mem);
+		GEM_BUG_ON(ret);
+	}
+
 	if (!io_mapping_init_wc(&mem->iomap,
 				mem->io_start,
 				resource_size(&mem->region)))
@@ -65,3 +123,35 @@ const struct intel_memory_region_ops intel_region_lmem_ops = {
 	.release = region_lmem_release,
 	.create_object = lmem_create_object,
 };
+
+struct intel_memory_region *
+intel_setup_fake_lmem(struct drm_i915_private *i915)
+{
+	struct pci_dev *pdev = i915->drm.pdev;
+	struct intel_memory_region *mem;
+	resource_size_t mappable_end;
+	resource_size_t io_start;
+	resource_size_t start;
+
+	GEM_BUG_ON(HAS_MAPPABLE_APERTURE(i915));
+	GEM_BUG_ON(!intel_graphics_fake_lmem_res.start);
+
+	/* Your mappable aperture belongs to me now! */
+	mappable_end = pci_resource_len(pdev, 2);
+	io_start = pci_resource_start(pdev, 2),
+	start = intel_graphics_fake_lmem_res.start;
+
+	mem = intel_memory_region_create(i915,
+					 start,
+					 mappable_end,
+					 I915_GTT_PAGE_SIZE_4K,
+					 io_start,
+					 &intel_region_lmem_ops);
+	if (!IS_ERR(mem)) {
+		DRM_INFO("Intel graphics fake LMEM: %pR\n", &mem->region);
+		DRM_INFO("Intel graphics fake LMEM IO start: %llx\n",
+			 (u64)mem->io_start);
+	}
+
+	return mem;
+}
diff --git a/drivers/gpu/drm/i915/intel_region_lmem.h b/drivers/gpu/drm/i915/intel_region_lmem.h
index ed2a3bab6443..213def7c7b8a 100644
--- a/drivers/gpu/drm/i915/intel_region_lmem.h
+++ b/drivers/gpu/drm/i915/intel_region_lmem.h
@@ -6,6 +6,11 @@
 #ifndef __INTEL_REGION_LMEM_H
 #define __INTEL_REGION_LMEM_H
 
+struct drm_i915_private;
+
 extern const struct intel_memory_region_ops intel_region_lmem_ops;
 
+struct intel_memory_region *
+intel_setup_fake_lmem(struct drm_i915_private *i915);
+
 #endif /* !__INTEL_REGION_LMEM_H */
diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index 6722005884db..271980225deb 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -39,6 +39,9 @@ bool i915_gpu_turbo_disable(void);
 /* Exported from arch/x86/kernel/early-quirks.c */
 extern struct resource intel_graphics_stolen_res;
 
+/* Exported from arch/x86/kernel/early-printk.c */
+extern struct resource intel_graphics_fake_lmem_res;
+
 /*
  * The Bridge device's PCI config space has information about the
  * fb aperture size and the amount of pre-reserved memory.
-- 
2.20.1

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