// SPDX-License-Identifier: GPL-2.0+
/*
 * R-Car Display Unit Channels Pair
 *
 * Copyright (C) 2013-2015 Renesas Electronics Corporation
 *
 * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 */

/*
 * 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;

        if (rgrp->channels_mask & BIT(0))
                defr6 |= DEFR6_ODPM02_DISP;

        if (rgrp->channels_mask & BIT(1))
                defr6 |= DEFR6_ODPM12_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;
        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) {
                        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, and DPAD routing
                 * is set in the group corresponding to the DPAD output (no Gen3
                 * SoC has multiple DPAD sources belonging to separate groups).
                 */
                if (rgrp->index == rcdu->dpad0_source / 2)
                        defr8 |= DEFR8_DRGBS_DU(rcdu->dpad0_source);
        }

        rcar_du_group_write(rgrp, DEFR8, defr8);
}

static void rcar_du_group_setup_didsr(struct rcar_du_group *rgrp)
{
        struct rcar_du_device *rcdu = rgrp->dev;
        struct rcar_du_crtc *rcrtc;
        unsigned int num_crtcs = 0;
        unsigned int i;
        u32 didsr;

        /*
         * Configure input dot clock routing with a hardcoded configuration. If
         * the DU channel can use the LVDS encoder output clock as the dot
         * clock, do so. Otherwise route DU_DOTCLKINn signal to DUn.
         *
         * Each channel can then select between the dot clock configured here
         * and the clock provided by the CPG through the ESCR register.
         */
        if (rcdu->info->gen < 3 && rgrp->index == 0) {
                /*
                 * On Gen2 a single register in the first group controls dot
                 * clock selection for all channels.
                 */
                rcrtc = rcdu->crtcs;
                num_crtcs = rcdu->num_crtcs;
        } else if ((rcdu->info->gen == 3 && rgrp->num_crtcs > 1) ||
                   rcdu->info->gen == 4) {
                /*
                 * On Gen3 dot clocks are setup through per-group registers,
                 * only available when the group has two channels.
                 * On Gen4 the registers are there for single channel too.
                 */
                rcrtc = &rcdu->crtcs[rgrp->index * 2];
                num_crtcs = rgrp->num_crtcs;
        }

        if (!num_crtcs)
                return;

        didsr = DIDSR_CODE;
        for (i = 0; i < num_crtcs; ++i, ++rcrtc) {
                if (rcdu->info->lvds_clk_mask & BIT(rcrtc->index))
                        didsr |= DIDSR_LDCS_LVDS0(i)
                              |  DIDSR_PDCS_CLK(i, 0);
                else if (rcdu->info->dsi_clk_mask & BIT(rcrtc->index))
                        didsr |= DIDSR_LDCS_DSI(i);
                else
                        didsr |= DIDSR_LDCS_DCLKIN(i)
                              |  DIDSR_PDCS_CLK(i, 0);
        }

        rcar_du_group_write(rgrp, DIDSR, didsr);
}

static void rcar_du_group_setup(struct rcar_du_group *rgrp)
{
        struct rcar_du_device *rcdu = rgrp->dev;
        u32 defr7 = DEFR7_CODE;
        u32 dorcr;

        /* 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);

        if (rcdu->info->gen < 4)
                rcar_du_group_setup_pins(rgrp);

        if (rcdu->info->gen < 4) {
                /*
                 * TODO: Handle routing of the DU output to CMM dynamically, as
                 * we should bypass CMM completely when no color management
                 * feature is used.
                 */
                defr7 |= (rgrp->cmms_mask & BIT(1) ? DEFR7_CMME1 : 0) |
                         (rgrp->cmms_mask & BIT(0) ? DEFR7_CMME0 : 0);
                rcar_du_group_write(rgrp, DEFR7, defr7);
        }

        if (rcdu->info->gen >= 2) {
                if (rcdu->info->gen < 4)
                        rcar_du_group_setup_defr8(rgrp);
                rcar_du_group_setup_didsr(rgrp);
        }

        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.
         *
         * Groups that have a single channel have a hardcoded configuration. On
         * Gen3 and newer, the documentation requires PG1T, DK1S and PG1D_DS1 to
         * always be set in this case.
         */
        dorcr = DORCR_PG0D_DS0 | DORCR_DPRS;
        if (rcdu->info->gen >= 3 && rgrp->num_crtcs == 1)
                dorcr |= DORCR_PG1T | DORCR_DK1S | DORCR_PG1D_DS1;
        rcar_du_group_write(rgrp, DORCR, dorcr);

        /*
         * DPTSR is used to select the source for the planes of a group. The
         * first source is chosen by writing 0 to the respective bits, and this
         * is always the default value of the register. In other words, writing
         * DPTSR is only needed if the SoC supports choosing the second source.
         *
         * The SoCs documentations seems to confirm this, as the DPTSR register
         * is not documented if only the first source exists on that SoC.
         */
        if (rgrp->channels_mask & BIT(1)) {
                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)
{
        struct rcar_du_device *rcdu = rgrp->dev;

        /*
         * Group start/stop is controlled by the DRES and DEN bits of DSYSR0
         * for the first group and DSYSR2 for the second group. On most DU
         * instances, this maps to the first CRTC of the group, and we can just
         * use rcar_du_crtc_dsysr_clr_set() to access the correct DSYSR. On
         * M3-N, however, DU2 doesn't exist, but DSYSR2 does. We thus need to
         * access the register directly using group read/write.
         */
        if (rcdu->info->channels_mask & BIT(rgrp->index * 2)) {
                struct rcar_du_crtc *rcrtc = &rgrp->dev->crtcs[rgrp->index * 2];

                rcar_du_crtc_dsysr_clr_set(rcrtc, DSYSR_DRES | DSYSR_DEN,
                                           start ? DSYSR_DEN : DSYSR_DRES);
        } else {
                rcar_du_group_write(rgrp, DSYSR,
                                    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 (rcdu->info->gen < 2)
                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;
}

static void rcar_du_group_set_dpad_levels(struct rcar_du_group *rgrp)
{
        static const u32 doflr_values[2] = {
                DOFLR_HSYCFL0 | DOFLR_VSYCFL0 | DOFLR_ODDFL0 |
                DOFLR_DISPFL0 | DOFLR_CDEFL0  | DOFLR_RGBFL0,
                DOFLR_HSYCFL1 | DOFLR_VSYCFL1 | DOFLR_ODDFL1 |
                DOFLR_DISPFL1 | DOFLR_CDEFL1  | DOFLR_RGBFL1,
        };
        static const u32 dpad_mask = BIT(RCAR_DU_OUTPUT_DPAD1)
                                   | BIT(RCAR_DU_OUTPUT_DPAD0);
        struct rcar_du_device *rcdu = rgrp->dev;
        u32 doflr = DOFLR_CODE;
        unsigned int i;

        if (rcdu->info->gen < 2)
                return;

        /*
         * The DPAD outputs can't be controlled directly. However, the parallel
         * output of the DU channels routed to DPAD can be set to fixed levels
         * through the DOFLR group register. Use this to turn the DPAD on or off
         * by driving fixed low-level signals at the output of any DU channel
         * not routed to a DPAD output. This doesn't affect the DU output
         * signals going to other outputs, such as the internal LVDS and HDMI
         * encoders.
         */

        for (i = 0; i < rgrp->num_crtcs; ++i) {
                struct rcar_du_crtc_state *rstate;
                struct rcar_du_crtc *rcrtc;

                rcrtc = &rcdu->crtcs[rgrp->index * 2 + i];
                rstate = to_rcar_crtc_state(rcrtc->crtc.state);

                if (!(rstate->outputs & dpad_mask))
                        doflr |= doflr_values[i];
        }

        rcar_du_group_write(rgrp, DOFLR, doflr);
}

int rcar_du_group_set_routing(struct rcar_du_group *rgrp)
{
        struct rcar_du_device *rcdu = rgrp->dev;
        u32 dorcr = rcar_du_group_read(rgrp, DORCR);

        dorcr &= ~(DORCR_PG1T | DORCR_DK1S | DORCR_PG1D_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 (rcdu->dpad1_source == rgrp->index * 2)
                dorcr |= DORCR_PG1D_DS0;
        else
                dorcr |= DORCR_PG1T | DORCR_DK1S | DORCR_PG1D_DS1;

        rcar_du_group_write(rgrp, DORCR, dorcr);

        rcar_du_group_set_dpad_levels(rgrp);

        return rcar_du_set_dpad0_vsp1_routing(rgrp->dev);
}