[PATCH v2 36/37] HAX drm/i915: add the fake lmem region

Matthew Auld
2019-06-27T20:57:24Z

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>
---
drivers/gpu/drm/i915/i915_drv.c | 15 +++++
drivers/gpu/drm/i915/i915_drv.h | 2 +
drivers/gpu/drm/i915/i915_gem_gtt.c | 3 +
drivers/gpu/drm/i915/i915_params.c | 3 +
drivers/gpu/drm/i915/i915_params.h | 3 +-
drivers/gpu/drm/i915/intel_memory_region.h | 4 ++
drivers/gpu/drm/i915/intel_region_lmem.c | 76 ++++++++++++++++++++++
drivers/gpu/drm/i915/intel_region_lmem.h | 3 +
8 files changed, 108 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 3d6fe993f26e..891937de6a2b 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1869,6 +1869,9 @@ static void i915_driver_destroy(struct drm_i915_private *i915)
pci_set_drvdata(pdev, NULL);
}

+struct resource intel_graphics_fake_lmem_res __ro_after_init = DEFINE_RES_MEM(0, 0);
+EXPORT_SYMBOL(intel_graphics_fake_lmem_res);
+
/**
* i915_driver_load - setup chip and create an initial config
* @pdev: PCI device
@@ -1895,6 +1898,18 @@ int i915_driver_load(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 need fake LMEM */
+ if (INTEL_GEN(dev_priv) >= 9 && i915_modparams.fake_lmem_start > 0) {
+ intel_graphics_fake_lmem_res.start = i915_modparams.fake_lmem_start;
+ intel_graphics_fake_lmem_res.end = SZ_2G; /* Placeholder; depends on aperture size */
+
+ mkwrite_device_info(dev_priv)->memory_regions =
+ REGION_SMEM | REGION_LMEM;
+ GEM_BUG_ON(!HAS_LMEM(dev_priv));
+
+ pr_info("Intel graphics fake LMEM starts at %pa\n", &intel_graphics_fake_lmem_res.start);
+ }
+
ret = pci_enable_device(pdev);
if (ret)
goto out_fini;
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 715e630a872d..9a2c79fa8088 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2815,4 +2815,6 @@ static inline void add_taint_for_CI(unsigned int taint)
add_taint(taint, LOCKDEP_STILL_OK);
}

+extern struct resource intel_graphics_fake_lmem_res;
+
#endif
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 3a8965048a06..df4928c8b10a 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2938,6 +2938,9 @@ 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 = i915_gem_setup_fake_lmem(i915);
+ break;
}

if (IS_ERR(mem)) {
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 296452f9efe4..59a6ad6261b9 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -164,6 +164,9 @@ i915_param_named_unsafe(dmc_firmware_path, charp, 0400,
i915_param_named_unsafe(enable_dp_mst, bool, 0600,
"Enable multi-stream transport (MST) for new DisplayPort sinks. (default: true)");

+i915_param_named_unsafe(fake_lmem_start, ulong, 0600,
+ "Fake LMEM start offset (default: 0)");
+
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
i915_param_named_unsafe(inject_load_failure, uint, 0400,
"Force an error after a number of failure check points (0:disabled (default), N:force failure at the Nth failure check point)");
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index d29ade3b7de6..b9698722c957 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -77,7 +77,8 @@ struct drm_printer;
param(bool, verbose_state_checks, true) \
param(bool, nuclear_pageflip, false) \
param(bool, enable_dp_mst, true) \
- param(bool, enable_gvt, false)
+ param(bool, enable_gvt, false) \
+ param(unsigned long, fake_lmem_start, 0)

#define MEMBER(T, member, ...) T member;
struct i915_params {
diff --git a/drivers/gpu/drm/i915/intel_memory_region.h b/drivers/gpu/drm/i915/intel_memory_region.h
index bee0c022d295..4960096ec30f 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"

@@ -71,6 +72,9 @@ 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;

diff --git a/drivers/gpu/drm/i915/intel_region_lmem.c b/drivers/gpu/drm/i915/intel_region_lmem.c
index 7003e7bff90c..2028261f4e80 100644
--- a/drivers/gpu/drm/i915/intel_region_lmem.c
+++ b/drivers/gpu/drm/i915/intel_region_lmem.c
@@ -241,9 +241,41 @@ lmem_create_object(struct intel_memory_region *mem,
return obj;
}

+static int i915_gem_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;
+
+ 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;
+
+ /* 1:1 map the mappable aperture to our reserved region */
+ for (n = 0; n < mem->fake_mappable.size >> PAGE_SHIFT; ++n) {
+ ggtt->vm.insert_page(&ggtt->vm,
+ mem->region.start + (n << PAGE_SHIFT),
+ n << PAGE_SHIFT, I915_CACHE_NONE, 0);
+ }
+
+ return 0;
+}
+
+static void i915_gem_relase_fake_lmem_bar(struct intel_memory_region *mem)
+{
+ if (drm_mm_node_allocated(&mem->fake_mappable))
+ drm_mm_remove_node(&mem->fake_mappable);
+}
+
static void
region_lmem_release(struct intel_memory_region *mem)
{
+ i915_gem_relase_fake_lmem_bar(mem);
io_mapping_fini(&mem->iomap);
i915_memory_region_release_buddy(mem);
}
@@ -253,6 +285,14 @@ region_lmem_init(struct intel_memory_region *mem)
{
int ret;

+ if (intel_graphics_fake_lmem_res.start) {
+ ret = i915_gem_init_fake_lmem_bar(mem);
+ if (ret) {
+ GEM_BUG_ON(1);
+ return ret;
+ }
+ }
+
if (!io_mapping_init_wc(&mem->iomap,
mem->io_start,
resource_size(&mem->region)))
@@ -278,6 +318,7 @@ 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 -= intel_graphics_fake_lmem_res.start;

return io_mapping_map_atomic_wc(&obj->memory_region->iomap, offset);
}
@@ -291,6 +332,7 @@ 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 -= intel_graphics_fake_lmem_res.start;

return io_mapping_map_wc(&obj->memory_region->iomap, offset, size);
}
@@ -307,6 +349,7 @@ resource_size_t i915_gem_object_lmem_io_offset(struct drm_i915_gem_object *obj,
* here, and elsewhere like in the gtt paths.
*/
daddr = i915_gem_object_get_dma_address(obj, n);
+ daddr -= intel_graphics_fake_lmem_res.start;

return mem->io_start + daddr;
}
@@ -326,3 +369,36 @@ i915_gem_object_create_lmem(struct drm_i915_private *i915,
return i915_gem_object_create_region(i915->regions[INTEL_MEMORY_LMEM],
size, flags);
}
+
+struct intel_memory_region *
+i915_gem_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,
+ &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 68232615a874..41bc411068de 100644
--- a/drivers/gpu/drm/i915/intel_region_lmem.h
+++ b/drivers/gpu/drm/i915/intel_region_lmem.h
@@ -24,4 +24,7 @@ i915_gem_object_create_lmem(struct drm_i915_private *i915,
resource_size_t size,
unsigned int flags);

+struct intel_memory_region *
+i915_gem_setup_fake_lmem(struct drm_i915_private *i915);
+
#endif /* !__INTEL_REGION_LMEM_H */
--
2.20.1