/*
 * rcar_du_group.c  --  R-Car Display Unit Channels Pair
 *
 * Copyright (C) 2013-2015 Renesas Electronics Corporation
 *
 * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

/*
 * The R8A7779 DU is split in per-CRTC resources (scan-out engine, blending
 * unit, timings generator, ...) and device-global resources (start/stop
 * control, planes, ...) shared between the two CRTCs.
 *
 * The R8A7790 introduced a third CRTC with its own set of global resources.
 * This would be modeled as two separate DU device instances if it wasn't for
 * a handful or resources that are shared between the three CRTCs (mostly
 * related to input and output routing). For this reason the R8A7790 DU must be
 * modeled as a single device with three CRTCs, two sets of "semi-global"
 * resources, and a few device-global resources.
 *
 * The rcar_du_group object is a driver specific object, without any real
 * counterpart in the DU documentation, that models those semi-global resources.
 */

#include <linux/clk.h>
#include <linux/io.h>

#include "rcar_du_drv.h"
#include "rcar_du_group.h"
#include "rcar_du_regs.h"

u32 rcar_du_group_read(struct rcar_du_group *rgrp, u32 reg)
{
	return rcar_du_read(rgrp->dev, rgrp->mmio_offset + reg);
}

void rcar_du_group_write(struct rcar_du_group *rgrp, u32 reg, u32 data)
{
	rcar_du_write(rgrp->dev, rgrp->mmio_offset + reg, data);
}

static void rcar_du_group_setup_pins(struct rcar_du_group *rgrp)
{
	u32 defr6 = DEFR6_CODE | DEFR6_ODPM12_DISP;

	if (rgrp->num_crtcs > 1)
		defr6 |= DEFR6_ODPM22_DISP;

	rcar_du_group_write(rgrp, DEFR6, defr6);
}

static void rcar_du_group_setup_defr8(struct rcar_du_group *rgrp)
{
	struct rcar_du_device *rcdu = rgrp->dev;
	unsigned int possible_crtcs =
		rcdu->info->routes[RCAR_DU_OUTPUT_DPAD0].possible_crtcs;
	u32 defr8 = DEFR8_CODE;

	if (rcdu->info->gen < 3) {
		defr8 |= DEFR8_DEFE8;

		/*
		 * On Gen2 the DEFR8 register for the first group also controls
		 * RGB output routing to DPAD0 and VSPD1 routing to DU0/1/2 for
		 * DU instances that support it.
		 */
		if (rgrp->index == 0) {
			if (possible_crtcs > 1)
				defr8 |= DEFR8_DRGBS_DU(rcdu->dpad0_source);
			if (rgrp->dev->vspd1_sink == 2)
				defr8 |= DEFR8_VSCS;
		}
	} else {
		/*
		 * On Gen3 VSPD routing can't be configured, but DPAD routing
		 * needs to be set despite having a single option available.
		 */
		u32 crtc = ffs(possible_crtcs) - 1;

		if (crtc / 2 == rgrp->index)
			defr8 |= DEFR8_DRGBS_DU(crtc);
	}

	rcar_du_group_write(rgrp, DEFR8, defr8);
}

static void rcar_du_group_setup(struct rcar_du_group *rgrp)
{
	struct rcar_du_device *rcdu = rgrp->dev;

	/* Enable extended features */
	rcar_du_group_write(rgrp, DEFR, DEFR_CODE | DEFR_DEFE);
	if (rcdu->info->gen < 3) {
		rcar_du_group_write(rgrp, DEFR2, DEFR2_CODE | DEFR2_DEFE2G);
		rcar_du_group_write(rgrp, DEFR3, DEFR3_CODE | DEFR3_DEFE3);
		rcar_du_group_write(rgrp, DEFR4, DEFR4_CODE);
	}
	rcar_du_group_write(rgrp, DEFR5, DEFR5_CODE | DEFR5_DEFE5);

	rcar_du_group_setup_pins(rgrp);

	if (rcar_du_has(rgrp->dev, RCAR_DU_FEATURE_EXT_CTRL_REGS)) {
		rcar_du_group_setup_defr8(rgrp);

		/*
		 * Configure input dot clock routing. We currently hardcode the
		 * configuration to routing DOTCLKINn to DUn. Register fields
		 * depend on the DU generation, but the resulting value is 0 in
		 * all cases.
		 *
		 * On Gen2 a single register in the first group controls dot
		 * clock selection for all channels, while on Gen3 dot clocks
		 * are setup through per-group registers, only available when
		 * the group has two channels.
		 */
		if ((rcdu->info->gen < 3 && rgrp->index == 0) ||
		    (rcdu->info->gen == 3 &&  rgrp->num_crtcs > 1))
			rcar_du_group_write(rgrp, DIDSR, DIDSR_CODE);
	}

	if (rcdu->info->gen >= 3)
		rcar_du_group_write(rgrp, DEFR10, DEFR10_CODE | DEFR10_DEFE10);

	/*
	 * Use DS1PR and DS2PR to configure planes priorities and connects the
	 * superposition 0 to DU0 pins. DU1 pins will be configured dynamically.
	 */
	rcar_du_group_write(rgrp, DORCR, DORCR_PG1D_DS1 | DORCR_DPRS);

	/* Apply planes to CRTCs association. */
	mutex_lock(&rgrp->lock);
	rcar_du_group_write(rgrp, DPTSR, (rgrp->dptsr_planes << 16) |
			    rgrp->dptsr_planes);
	mutex_unlock(&rgrp->lock);
}

/*
 * rcar_du_group_get - Acquire a reference to the DU channels group
 *
 * Acquiring the first reference setups core registers. A reference must be held
 * before accessing any hardware registers.
 *
 * This function must be called with the DRM mode_config lock held.
 *
 * Return 0 in case of success or a negative error code otherwise.
 */
int rcar_du_group_get(struct rcar_du_group *rgrp)
{
	if (rgrp->use_count)
		goto done;

	rcar_du_group_setup(rgrp);

done:
	rgrp->use_count++;
	return 0;
}

/*
 * rcar_du_group_put - Release a reference to the DU
 *
 * This function must be called with the DRM mode_config lock held.
 */
void rcar_du_group_put(struct rcar_du_group *rgrp)
{
	--rgrp->use_count;
}

static void __rcar_du_group_start_stop(struct rcar_du_group *rgrp, bool start)
{
	rcar_du_group_write(rgrp, DSYSR,
		(rcar_du_group_read(rgrp, DSYSR) & ~(DSYSR_DRES | DSYSR_DEN)) |
		(start ? DSYSR_DEN : DSYSR_DRES));
}

void rcar_du_group_start_stop(struct rcar_du_group *rgrp, bool start)
{
	/*
	 * Many of the configuration bits are only updated when the display
	 * reset (DRES) bit in DSYSR is set to 1, disabling *both* CRTCs. Some
	 * of those bits could be pre-configured, but others (especially the
	 * bits related to plane assignment to display timing controllers) need
	 * to be modified at runtime.
	 *
	 * Restart the display controller if a start is requested. Sorry for the
	 * flicker. It should be possible to move most of the "DRES-update" bits
	 * setup to driver initialization time and minimize the number of cases
	 * when the display controller will have to be restarted.
	 */
	if (start) {
		if (rgrp->used_crtcs++ != 0)
			__rcar_du_group_start_stop(rgrp, false);
		__rcar_du_group_start_stop(rgrp, true);
	} else {
		if (--rgrp->used_crtcs == 0)
			__rcar_du_group_start_stop(rgrp, false);
	}
}

void rcar_du_group_restart(struct rcar_du_group *rgrp)
{
	rgrp->need_restart = false;

	__rcar_du_group_start_stop(rgrp, false);
	__rcar_du_group_start_stop(rgrp, true);
}

int rcar_du_set_dpad0_vsp1_routing(struct rcar_du_device *rcdu)
{
	struct rcar_du_group *rgrp;
	struct rcar_du_crtc *crtc;
	unsigned int index;
	int ret;

	if (!rcar_du_has(rcdu, RCAR_DU_FEATURE_EXT_CTRL_REGS))
		return 0;

	/*
	 * RGB output routing to DPAD0 and VSP1D routing to DU0/1/2 are
	 * configured in the DEFR8 register of the first group on Gen2 and the
	 * last group on Gen3. As this function can be called with the DU
	 * channels of the corresponding CRTCs disabled, we need to enable the
	 * group clock before accessing the register.
	 */
	index = rcdu->info->gen < 3 ? 0 : DIV_ROUND_UP(rcdu->num_crtcs, 2) - 1;
	rgrp = &rcdu->groups[index];
	crtc = &rcdu->crtcs[index * 2];

	ret = clk_prepare_enable(crtc->clock);
	if (ret < 0)
		return ret;

	rcar_du_group_setup_defr8(rgrp);

	clk_disable_unprepare(crtc->clock);

	return 0;
}

int rcar_du_group_set_routing(struct rcar_du_group *rgrp)
{
	struct rcar_du_crtc *crtc0 = &rgrp->dev->crtcs[rgrp->index * 2];
	u32 dorcr = rcar_du_group_read(rgrp, DORCR);

	dorcr &= ~(DORCR_PG2T | DORCR_DK2S | DORCR_PG2D_MASK);

	/*
	 * Set the DPAD1 pins sources. Select CRTC 0 if explicitly requested and
	 * CRTC 1 in all other cases to avoid cloning CRTC 0 to DPAD0 and DPAD1
	 * by default.
	 */
	if (crtc0->outputs & BIT(RCAR_DU_OUTPUT_DPAD1))
		dorcr |= DORCR_PG2D_DS1;
	else
		dorcr |= DORCR_PG2T | DORCR_DK2S | DORCR_PG2D_DS2;

	rcar_du_group_write(rgrp, DORCR, dorcr);

	return rcar_du_set_dpad0_vsp1_routing(rgrp->dev);
}