/*
 * Copyright (C) 2013-2015 ARM Limited
 * Author: Liviu Dudau <Liviu.Dudau@arm.com>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 *
 *  Implementation of a CRTC class for the HDLCD driver.
 */

#include <linux/clk.h>
#include <linux/of_graph.h>
#include <linux/platform_data/simplefb.h>

#include <video/videomode.h>

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc.h>
#include <drm/drm_fb_cma_helper.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_of.h>
#include <drm/drm_plane_helper.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_vblank.h>

#include "hdlcd_drv.h"
#include "hdlcd_regs.h"

/*
 * The HDLCD controller is a dumb RGB streamer that gets connected to
 * a single HDMI transmitter or in the case of the ARM Models it gets
 * emulated by the software that does the actual rendering.
 *
 */

static void hdlcd_crtc_cleanup(struct drm_crtc *crtc)
{
        struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);

        /* stop the controller on cleanup */
        hdlcd_write(hdlcd, HDLCD_REG_COMMAND, 0);
        drm_crtc_cleanup(crtc);
}

static int hdlcd_crtc_enable_vblank(struct drm_crtc *crtc)
{
        struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
        unsigned int mask = hdlcd_read(hdlcd, HDLCD_REG_INT_MASK);

        hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, mask | HDLCD_INTERRUPT_VSYNC);

        return 0;
}

static void hdlcd_crtc_disable_vblank(struct drm_crtc *crtc)
{
        struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
        unsigned int mask = hdlcd_read(hdlcd, HDLCD_REG_INT_MASK);

        hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, mask & ~HDLCD_INTERRUPT_VSYNC);
}

static const struct drm_crtc_funcs hdlcd_crtc_funcs = {
        .destroy = hdlcd_crtc_cleanup,
        .set_config = drm_atomic_helper_set_config,
        .page_flip = drm_atomic_helper_page_flip,
        .reset = drm_atomic_helper_crtc_reset,
        .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
        .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
        .enable_vblank = hdlcd_crtc_enable_vblank,
        .disable_vblank = hdlcd_crtc_disable_vblank,
};

static struct simplefb_format supported_formats[] = SIMPLEFB_FORMATS;

/*
 * Setup the HDLCD registers for decoding the pixels out of the framebuffer
 */
static int hdlcd_set_pxl_fmt(struct drm_crtc *crtc)
{
        unsigned int btpp;
        struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
        const struct drm_framebuffer *fb = crtc->primary->state->fb;
        uint32_t pixel_format;
        struct simplefb_format *format = NULL;
        int i;

        pixel_format = fb->format->format;

        for (i = 0; i < ARRAY_SIZE(supported_formats); i++) {
                if (supported_formats[i].fourcc == pixel_format)
                        format = &supported_formats[i];
        }

        if (WARN_ON(!format))
                return 0;

        /* HDLCD uses 'bytes per pixel', zero means 1 byte */
        btpp = (format->bits_per_pixel + 7) / 8;
        hdlcd_write(hdlcd, HDLCD_REG_PIXEL_FORMAT, (btpp - 1) << 3);

        /*
         * The format of the HDLCD_REG_<color>_SELECT register is:
         *   - bits[23:16] - default value for that color component
         *   - bits[11:8]  - number of bits to extract for each color component
         *   - bits[4:0]   - index of the lowest bit to extract
         *
         * The default color value is used when bits[11:8] are zero, when the
         * pixel is outside the visible frame area or when there is a
         * buffer underrun.
         */
        hdlcd_write(hdlcd, HDLCD_REG_RED_SELECT, format->red.offset |
#ifdef CONFIG_DRM_HDLCD_SHOW_UNDERRUN
                    0x00ff0000 |        /* show underruns in red */
#endif
                    ((format->red.length & 0xf) << 8));
        hdlcd_write(hdlcd, HDLCD_REG_GREEN_SELECT, format->green.offset |
                    ((format->green.length & 0xf) << 8));
        hdlcd_write(hdlcd, HDLCD_REG_BLUE_SELECT, format->blue.offset |
                    ((format->blue.length & 0xf) << 8));

        return 0;
}

static void hdlcd_crtc_mode_set_nofb(struct drm_crtc *crtc)
{
        struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
        struct drm_display_mode *m = &crtc->state->adjusted_mode;
        struct videomode vm;
        unsigned int polarities, err;

        vm.vfront_porch = m->crtc_vsync_start - m->crtc_vdisplay;
        vm.vback_porch = m->crtc_vtotal - m->crtc_vsync_end;
        vm.vsync_len = m->crtc_vsync_end - m->crtc_vsync_start;
        vm.hfront_porch = m->crtc_hsync_start - m->crtc_hdisplay;
        vm.hback_porch = m->crtc_htotal - m->crtc_hsync_end;
        vm.hsync_len = m->crtc_hsync_end - m->crtc_hsync_start;

        polarities = HDLCD_POLARITY_DATAEN | HDLCD_POLARITY_DATA;

        if (m->flags & DRM_MODE_FLAG_PHSYNC)
                polarities |= HDLCD_POLARITY_HSYNC;
        if (m->flags & DRM_MODE_FLAG_PVSYNC)
                polarities |= HDLCD_POLARITY_VSYNC;

        /* Allow max number of outstanding requests and largest burst size */
        hdlcd_write(hdlcd, HDLCD_REG_BUS_OPTIONS,
                    HDLCD_BUS_MAX_OUTSTAND | HDLCD_BUS_BURST_16);

        hdlcd_write(hdlcd, HDLCD_REG_V_DATA, m->crtc_vdisplay - 1);
        hdlcd_write(hdlcd, HDLCD_REG_V_BACK_PORCH, vm.vback_porch - 1);
        hdlcd_write(hdlcd, HDLCD_REG_V_FRONT_PORCH, vm.vfront_porch - 1);
        hdlcd_write(hdlcd, HDLCD_REG_V_SYNC, vm.vsync_len - 1);
        hdlcd_write(hdlcd, HDLCD_REG_H_DATA, m->crtc_hdisplay - 1);
        hdlcd_write(hdlcd, HDLCD_REG_H_BACK_PORCH, vm.hback_porch - 1);
        hdlcd_write(hdlcd, HDLCD_REG_H_FRONT_PORCH, vm.hfront_porch - 1);
        hdlcd_write(hdlcd, HDLCD_REG_H_SYNC, vm.hsync_len - 1);
        hdlcd_write(hdlcd, HDLCD_REG_POLARITIES, polarities);

        err = hdlcd_set_pxl_fmt(crtc);
        if (err)
                return;

        clk_set_rate(hdlcd->clk, m->crtc_clock * 1000);
}

static void hdlcd_crtc_atomic_enable(struct drm_crtc *crtc,
                                     struct drm_atomic_state *state)
{
        struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);

        clk_prepare_enable(hdlcd->clk);
        hdlcd_crtc_mode_set_nofb(crtc);
        hdlcd_write(hdlcd, HDLCD_REG_COMMAND, 1);
        drm_crtc_vblank_on(crtc);
}

static void hdlcd_crtc_atomic_disable(struct drm_crtc *crtc,
                                      struct drm_atomic_state *state)
{
        struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);

        drm_crtc_vblank_off(crtc);
        hdlcd_write(hdlcd, HDLCD_REG_COMMAND, 0);
        clk_disable_unprepare(hdlcd->clk);
}

static enum drm_mode_status hdlcd_crtc_mode_valid(struct drm_crtc *crtc,
                const struct drm_display_mode *mode)
{
        struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
        long rate, clk_rate = mode->clock * 1000;

        rate = clk_round_rate(hdlcd->clk, clk_rate);
        /* 0.1% seems a close enough tolerance for the TDA19988 on Juno */
        if (abs(rate - clk_rate) * 1000 > clk_rate) {
                /* clock required by mode not supported by hardware */
                return MODE_NOCLOCK;
        }

        return MODE_OK;
}

static void hdlcd_crtc_atomic_begin(struct drm_crtc *crtc,
                                    struct drm_atomic_state *state)
{
        struct drm_pending_vblank_event *event = crtc->state->event;

        if (event) {
                crtc->state->event = NULL;

                spin_lock_irq(&crtc->dev->event_lock);
                if (drm_crtc_vblank_get(crtc) == 0)
                        drm_crtc_arm_vblank_event(crtc, event);
                else
                        drm_crtc_send_vblank_event(crtc, event);
                spin_unlock_irq(&crtc->dev->event_lock);
        }
}

static const struct drm_crtc_helper_funcs hdlcd_crtc_helper_funcs = {
        .mode_valid     = hdlcd_crtc_mode_valid,
        .atomic_begin   = hdlcd_crtc_atomic_begin,
        .atomic_enable  = hdlcd_crtc_atomic_enable,
        .atomic_disable = hdlcd_crtc_atomic_disable,
};

static int hdlcd_plane_atomic_check(struct drm_plane *plane,
                                    struct drm_atomic_state *state)
{
        struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state,
                                                                                 plane);
        int i;
        struct drm_crtc *crtc;
        struct drm_crtc_state *crtc_state;
        u32 src_h = new_plane_state->src_h >> 16;

        /* only the HDLCD_REG_FB_LINE_COUNT register has a limit */
        if (src_h >= HDLCD_MAX_YRES) {
                DRM_DEBUG_KMS("Invalid source width: %d\n", src_h);
                return -EINVAL;
        }

        for_each_new_crtc_in_state(state, crtc, crtc_state,
                                   i) {
                /* we cannot disable the plane while the CRTC is active */
                if (!new_plane_state->fb && crtc_state->active)
                        return -EINVAL;
                return drm_atomic_helper_check_plane_state(new_plane_state,
                                                           crtc_state,
                                                           DRM_PLANE_HELPER_NO_SCALING,
                                                           DRM_PLANE_HELPER_NO_SCALING,
                                                           false, true);
        }

        return 0;
}

static void hdlcd_plane_atomic_update(struct drm_plane *plane,
                                      struct drm_atomic_state *state)
{
        struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state,
                                                                                 plane);
        struct drm_framebuffer *fb = new_plane_state->fb;
        struct hdlcd_drm_private *hdlcd;
        u32 dest_h;
        dma_addr_t scanout_start;

        if (!fb)
                return;

        dest_h = drm_rect_height(&new_plane_state->dst);
        scanout_start = drm_fb_cma_get_gem_addr(fb, new_plane_state, 0);

        hdlcd = plane->dev->dev_private;
        hdlcd_write(hdlcd, HDLCD_REG_FB_LINE_LENGTH, fb->pitches[0]);
        hdlcd_write(hdlcd, HDLCD_REG_FB_LINE_PITCH, fb->pitches[0]);
        hdlcd_write(hdlcd, HDLCD_REG_FB_LINE_COUNT, dest_h - 1);
        hdlcd_write(hdlcd, HDLCD_REG_FB_BASE, scanout_start);
}

static const struct drm_plane_helper_funcs hdlcd_plane_helper_funcs = {
        .atomic_check = hdlcd_plane_atomic_check,
        .atomic_update = hdlcd_plane_atomic_update,
};

static const struct drm_plane_funcs hdlcd_plane_funcs = {
        .update_plane           = drm_atomic_helper_update_plane,
        .disable_plane          = drm_atomic_helper_disable_plane,
        .destroy                = drm_plane_cleanup,
        .reset                  = drm_atomic_helper_plane_reset,
        .atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
        .atomic_destroy_state   = drm_atomic_helper_plane_destroy_state,
};

static struct drm_plane *hdlcd_plane_init(struct drm_device *drm)
{
        struct hdlcd_drm_private *hdlcd = drm->dev_private;
        struct drm_plane *plane = NULL;
        u32 formats[ARRAY_SIZE(supported_formats)], i;
        int ret;

        plane = devm_kzalloc(drm->dev, sizeof(*plane), GFP_KERNEL);
        if (!plane)
                return ERR_PTR(-ENOMEM);

        for (i = 0; i < ARRAY_SIZE(supported_formats); i++)
                formats[i] = supported_formats[i].fourcc;

        ret = drm_universal_plane_init(drm, plane, 0xff, &hdlcd_plane_funcs,
                                       formats, ARRAY_SIZE(formats),
                                       NULL,
                                       DRM_PLANE_TYPE_PRIMARY, NULL);
        if (ret)
                return ERR_PTR(ret);

        drm_plane_helper_add(plane, &hdlcd_plane_helper_funcs);
        hdlcd->plane = plane;

        return plane;
}

int hdlcd_setup_crtc(struct drm_device *drm)
{
        struct hdlcd_drm_private *hdlcd = drm->dev_private;
        struct drm_plane *primary;
        int ret;

        primary = hdlcd_plane_init(drm);
        if (IS_ERR(primary))
                return PTR_ERR(primary);

        ret = drm_crtc_init_with_planes(drm, &hdlcd->crtc, primary, NULL,
                                        &hdlcd_crtc_funcs, NULL);
        if (ret)
                return ret;

        drm_crtc_helper_add(&hdlcd->crtc, &hdlcd_crtc_helper_funcs);
        return 0;
}