drivers/gpu/drm/i915/display/intel_mchbar.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/i915/display/intel_mchbar.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/i915/display/intel_mchbar.c
Extension
.c
Size
1855 bytes
Lines
79
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: MIT
/*
 * Copyright © 2026 Intel Corporation
 */

#include <linux/minmax.h>

#include <drm/drm_print.h>

#include "intel_de.h"
#include "intel_display_core.h"
#include "intel_mchbar.h"

static bool has_mchbar_mirror(struct intel_display *display)
{
	return DISPLAY_VER(display) < 14;
}

static u32 mchbar_mirror_base(struct intel_display *display)
{
	if (DISPLAY_VER(display) >= 6)
		return MCHBAR_MIRROR_BASE_SNB;
	else
		return MCHBAR_MIRROR_BASE;
}

static u32 mchbar_mirror_end(struct intel_display *display)
{
	if (DISPLAY_VER(display) >= 12 && !display->platform.rocketlake)
		return MCHBAR_MIRROR_END_TGL;
	else if (DISPLAY_VER(display) >= 11)
		return MCHBAR_MIRROR_END_ICL_RKL;
	else if (DISPLAY_VER(display) >= 6)
		return MCHBAR_MIRROR_END_SNB;
	else
		return MCHBAR_MIRROR_END;
}

static u32 mchbar_mirror_len(struct intel_display *display)
{
	return mchbar_mirror_end(display) - mchbar_mirror_base(display) + 1;
}

static bool is_mchbar_reg(struct intel_display *display, intel_reg_t reg)
{
	return has_mchbar_mirror(display) &&
		in_range32(intel_reg_offset(reg),
			   mchbar_mirror_base(display),
			   mchbar_mirror_len(display));
}

static void assert_is_mchbar_reg(struct intel_display *display, intel_reg_t reg)
{
	drm_WARN(display->drm, !is_mchbar_reg(display, reg),
		 "Reading non-MCHBAR register 0x%x\n",
		 intel_reg_offset(reg));
}

u16 intel_mchbar_read16(struct intel_display *display, intel_reg_t reg)
{
	assert_is_mchbar_reg(display, reg);

	return intel_de_read16(display, reg);
}

u32 intel_mchbar_read(struct intel_display *display, intel_reg_t reg)
{
	assert_is_mchbar_reg(display, reg);

	return intel_de_read(display, reg);
}

u64 intel_mchbar_read64_2x32(struct intel_display *display, intel_reg_t reg)
{
	assert_is_mchbar_reg(display, reg);

	return intel_de_read64_2x32(display, reg);
}

Annotation

Implementation Notes