path: root/drivers/gpu/drm/i915/gem/i915_gem_stolen.c

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright © 2008-2012 Intel Corporation
 */

#include <linux/errno.h>
#include <linux/mutex.h>

#include <drm/drm_mm.h>
#include <drm/i915_drm.h>

#include "gem/i915_gem_lmem.h"
#include "gem/i915_gem_region.h"
#include "gt/intel_gt.h"
#include "gt/intel_gt_mcr.h"
#include "gt/intel_gt_regs.h"
#include "gt/intel_region_lmem.h"
#include "i915_drv.h"
#include "i915_gem_stolen.h"
#include "i915_pci.h"
#include "i915_reg.h"
#include "i915_utils.h"
#include "i915_vgpu.h"
#include "intel_mchbar_regs.h"
#include "intel_pci_config.h"

/*
 * The BIOS typically reserves some of the system's memory for the exclusive
 * use of the integrated graphics. This memory is no longer available for
 * use by the OS and so the user finds that his system has less memory
 * available than he put in. We refer to this memory as stolen.
 *
 * The BIOS will allocate its framebuffer from the stolen memory. Our
 * goal is try to reuse that object for our own fbcon which must always
 * be available for panics. Anything else we can reuse the stolen memory
 * for is a boon.
 */

int i915_gem_stolen_insert_node_in_range(struct drm_i915_private *i915,
					 struct drm_mm_node *node, u64 size,
					 unsigned alignment, u64 start, u64 end)
{
	int ret;

	if (!drm_mm_initialized(&i915->mm.stolen))
		return -ENODEV;

	/* WaSkipStolenMemoryFirstPage:bdw+ */
	if (GRAPHICS_VER(i915) >= 8 && start < 4096)
		start = 4096;

	mutex_lock(&i915->mm.stolen_lock);
	ret = drm_mm_insert_node_in_range(&i915->mm.stolen, node,
					  size, alignment, 0,
					  start, end, DRM_MM_INSERT_BEST);
	mutex_unlock(&i915->mm.stolen_lock);

	return ret;
}

int i915_gem_stolen_insert_node(struct drm_i915_private *i915,
				struct drm_mm_node *node, u64 size,
				unsigned alignment)
{
	return i915_gem_stolen_insert_node_in_range(i915, node,
						    size, alignment,
						    I915_GEM_STOLEN_BIAS,
						    U64_MAX);
}

void i915_gem_stolen_remove_node(struct drm_i915_private *i915,
				 struct drm_mm_node *node)
{
	mutex_lock(&i915->mm.stolen_lock);
	drm_mm_remove_node(node);
	mutex_unlock(&i915->mm.stolen_lock);
}

static bool valid_stolen_size(struct drm_i915_private *i915, struct resource *dsm)
{
	return (dsm->start != 0 || HAS_LMEMBAR_SMEM_STOLEN(i915)) && dsm->end > dsm->start;
}

static int adjust_stolen(struct drm_i915_private *i915,
			 struct resource *dsm)
{
	struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
	struct intel_uncore *uncore = ggtt->vm.gt->uncore;

	if (!valid_stolen_size(i915, dsm))
		return -EINVAL;

	/*
	 * Make sure we don't clobber the GTT if it's within stolen memory
	 *
	 * TODO: We have yet too encounter the case where the GTT wasn't at the
	 * end of stolen. With that assumption we could simplify this.
	 */
	if (GRAPHICS_VER(i915) <= 4 &&
	    !IS_G33(i915) && !IS_PINEVIEW(i915) && !IS_G4X(i915)) {
		struct resource stolen[2] = {*dsm, *dsm};
		struct resource ggtt_res;
		resource_size_t ggtt_start;

		ggtt_start = intel_uncore_read(uncore, PGTBL_CTL);
		if (GRAPHICS_VER(i915) == 4)
			ggtt_start = (ggtt_start & PGTBL_ADDRESS_LO_MASK) |
				     (ggtt_start & PGTBL_ADDRESS_HI_MASK) << 28;
		else
			ggtt_start &= PGTBL_ADDRESS_LO_MASK;

		ggtt_res = DEFINE_RES_MEM(ggtt_start, ggtt_total_entries(ggtt) * 4);

		if (ggtt_res.start >= stolen[0].start && ggtt_res.start < stolen[0].end)
			stolen[0].end = ggtt_res.start;
		if (ggtt_res.end > stolen[1].start && ggtt_res.end <= stolen[1].end)
			stolen[1].start = ggtt_res.end;

		/* Pick the larger of the two chunks */
		if (resource_size(&stolen[0]) > resource_size(&stolen[1]))
			*dsm = stolen[0];
		else
			*dsm = stolen[1];

		if (stolen[0].start != stolen[1].start ||
		    stolen[0].end != stolen[1].end) {
			drm_dbg(&i915->drm,
				"GTT within stolen memory at %pR\n",
				&ggtt_res);
			drm_dbg(&i915->drm, "Stolen memory adjusted to %pR\n",
				dsm);
		}
	}

	if (!valid_stolen_size(i915, dsm))
		return -EINVAL;

	return 0;
}

static int request_smem_stolen(struct drm_i915_private *i915,
			       struct resource *dsm)
{
	struct resource *r;

	/*
	 * With stolen lmem, we don't need to request system memory for the
	 * address range since it's local to the gpu.
	 *
	 * Starting MTL, in IGFX devices the stolen memory is exposed via
	 * LMEMBAR and shall be considered similar to stolen lmem.
	 */
	if (HAS_LMEM(i915) || HAS_LMEMBAR_SMEM_STOLEN(i915))
		return 0;

	/*
	 * Verify that nothing else uses this physical address. Stolen
	 * memory should be reserved by the BIOS and hidden from the
	 * kernel. So if the region is already marked as busy, something
	 * is seriously wrong.
	 */
	r = devm_request_mem_region(i915->drm.dev, dsm->start,
				    resource_size(dsm),
				    "Graphics Stolen Memory");
	if (r == NULL