linux/drivers/gpu/drm/i915/display/intel_dmc_wl.c

// SPDX-License-Identifier: MIT
/*
 * Copyright (C) 2024 Intel Corporation
 */

#include <linux/kernel.h>

#include "intel_de.h"
#include "intel_dmc.h"
#include "intel_dmc_regs.h"
#include "intel_dmc_wl.h"

/**
 * DOC: DMC wakelock support
 *
 * Wake lock is the mechanism to cause display engine to exit DC
 * states to allow programming to registers that are powered down in
 * those states. Previous projects exited DC states automatically when
 * detecting programming. Now software controls the exit by
 * programming the wake lock. This improves system performance and
 * system interactions and better fits the flip queue style of
 * programming. Wake lock is only required when DC5, DC6, or DC6v have
 * been enabled in DC_STATE_EN and the wake lock mode of operation has
 * been enabled.
 *
 * The wakelock mechanism in DMC allows the display engine to exit DC
 * states explicitly before programming registers that may be powered
 * down.  In earlier hardware, this was done automatically and
 * implicitly when the display engine accessed a register.  With the
 * wakelock implementation, the driver asserts a wakelock in DMC,
 * which forces it to exit the DC state until the wakelock is
 * deasserted.
 *
 * The mechanism can be enabled and disabled by writing to the
 * DMC_WAKELOCK_CFG register.  There are also 13 control registers
 * that can be used to hold and release different wakelocks.  In the
 * current implementation, we only need one wakelock, so only
 * DMC_WAKELOCK1_CTL is used.  The other definitions are here for
 * potential future use.
 */

#define DMC_WAKELOCK_CTL_TIMEOUT …
#define DMC_WAKELOCK_HOLD_TIME …

struct intel_dmc_wl_range { … };

static struct intel_dmc_wl_range lnl_wl_range[] = …;

static void __intel_dmc_wl_release(struct intel_display *display)
{ … }

static void intel_dmc_wl_work(struct work_struct *work)
{ … }

static bool intel_dmc_wl_check_range(u32 address)
{ … }

static bool __intel_dmc_wl_supported(struct intel_display *display)
{ … }

void intel_dmc_wl_init(struct intel_display *display)
{ … }

void intel_dmc_wl_enable(struct intel_display *display)
{ … }

void intel_dmc_wl_disable(struct intel_display *display)
{ … }

void intel_dmc_wl_get(struct intel_display *display, i915_reg_t reg)
{ … }

void intel_dmc_wl_put(struct intel_display *display, i915_reg_t reg)
{ … }