/*
 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
 * Parts of this file were based on sources as follows:
 *
 * Copyright (C) 2006-2008 Intel Corporation
 * Copyright (C) 2007 Amos Lee <amos_lee@storlinksemi.com>
 * Copyright (C) 2007 Dave Airlie <airlied@linux.ie>
 * Copyright (C) 2011 Texas Instruments
 * Copyright (C) 2017 Eric Anholt
 *
 * This program is free software and is provided to you under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation, and any use by you of this program is subject to the terms of
 * such GNU licence.
 */
#include <linux/clk.h>
#include <linux/version.h>
#include <linux/dma-buf.h>
#include <linux/of_graph.h>
#include <linux/delay.h>

#include <drm/drmP.h>
#include <drm/drm_panel.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_fb_cma_helper.h>

#include "tve200_drm.h"

irqreturn_t tve200_irq(int irq, void *data)
{
	struct tve200_drm_dev_private *priv = data;
	u32 stat;
	u32 val;

	stat = readl(priv->regs + TVE200_INT_STAT);

	if (!stat)
		return IRQ_NONE;

	/*
	 * Vblank IRQ
	 *
	 * The hardware is a bit tilted: the line stays high after clearing
	 * the vblank IRQ, firing many more interrupts. We counter this
	 * by toggling the IRQ back and forth from firing at vblank and
	 * firing at start of active image, which works around the problem
	 * since those occur strictly in sequence, and we get two IRQs for each
	 * frame, one at start of Vblank (that we make call into the CRTC) and
	 * another one at the start of the image (that we discard).
	 */
	if (stat & TVE200_INT_V_STATUS) {
		val = readl(priv->regs + TVE200_CTRL);
		/* We have an actual start of vsync */
		if (!(val & TVE200_VSTSTYPE_BITS)) {
			drm_crtc_handle_vblank(&priv->pipe.crtc);
			/* Toggle trigger to start of active image */
			val |= TVE200_VSTSTYPE_VAI;
		} else {
			/* Toggle trigger back to start of vsync */
			val &= ~TVE200_VSTSTYPE_BITS;
		}
		writel(val, priv->regs + TVE200_CTRL);
	} else
		dev_err(priv->drm->dev, "stray IRQ %08x\n", stat);

	/* Clear the interrupt once done */
	writel(stat, priv->regs + TVE200_INT_CLR);

	return IRQ_HANDLED;
}

static int tve200_display_check(struct drm_simple_display_pipe *pipe,
			       struct drm_plane_state *pstate,
			       struct drm_crtc_state *cstate)
{
	const struct drm_display_mode *mode = &cstate->mode;
	struct drm_framebuffer *old_fb = pipe->plane.state->fb;
	struct drm_framebuffer *fb = pstate->fb;

	/*
	 * We support these specific resolutions and nothing else.
	 */
	if (!(mode->hdisplay == 352 && mode->vdisplay == 240) && /* SIF(525) */
	    !(mode->hdisplay == 352 && mode->vdisplay == 288) && /* CIF(625) */
	    !(mode->hdisplay == 640 && mode->vdisplay == 480) && /* VGA */
	    !(mode->hdisplay == 720 && mode->vdisplay == 480) && /* D1 */
	    !(mode->hdisplay == 720 && mode->vdisplay == 576)) { /* D1 */
		DRM_DEBUG_KMS("unsupported display mode (%u x %u)\n",
			mode->hdisplay, mode->vdisplay);
		return -EINVAL;
	}

	if (fb) {
		u32 offset = drm_fb_cma_get_gem_addr(fb, pstate, 0);

		/* FB base address must be dword aligned. */
		if (offset & 3) {
			DRM_DEBUG_KMS("FB not 32-bit aligned\n");
			return -EINVAL;
		}

		/*
		 * There's no pitch register, the mode's hdisplay
		 * controls this.
		 */
		if (fb->pitches[0] != mode->hdisplay * fb->format->cpp[0]) {
			DRM_DEBUG_KMS("can't handle pitches\n");
			return -EINVAL;
		}

		/*
		 * We can't change the FB format in a flicker-free
		 * manner (and only update it during CRTC enable).
		 */
		if (old_fb && old_fb->format != fb->format)
			cstate->mode_changed = true;
	}

	return 0;
}

static void tve200_display_enable(struct drm_simple_display_pipe *pipe,
				 struct drm_crtc_state *cstate,
				 struct drm_plane_state *plane_state)
{
	struct drm_crtc *crtc = &pipe->crtc;
	struct drm_plane *plane = &pipe->plane;
	struct drm_device *drm = crtc->dev;
	struct tve200_drm_dev_private *priv = drm->dev_private;
	const struct drm_display_mode *mode = &cstate->mode;
	struct drm_framebuffer *fb = plane->state->fb;
	struct drm_connector *connector = priv->connector;
	u32 format = fb->format->format;
	u32 ctrl1 = 0;
	int retries;

	clk_prepare_enable(priv->clk);

	/* Reset the TVE200 and wait for it to come back online */
	writel(TVE200_CTRL_4_RESET, priv->regs + TVE200_CTRL_4);
	for (retries = 0; retries < 5; retries++) {
		usleep_range(30000, 50000);
		if (readl(priv->regs + TVE200_CTRL_4) & TVE200_CTRL_4_RESET)
			continue;
		else
			break;
	}
	if (retries == 5 &&
	    readl(priv->regs + TVE200_CTRL_4) & TVE200_CTRL_4_RESET) {
		dev_err(drm->dev, "can't get hardware out of reset\n");
		return;
	}

	/* Function 1 */
	ctrl1 |= TVE200_CTRL_CSMODE;
	/* Interlace mode for CCIR656: parameterize? */
	ctrl1 |= TVE200_CTRL_NONINTERLACE;
	/* 32 words per burst */
	ctrl1 |= TVE200_CTRL_BURST_32_WORDS;
	/* 16 retries */
	ctrl1 |= TVE200_CTRL_RETRYCNT_16;
	/* NTSC mode: parametrize? */
	ctrl1 |= TVE200_CTRL_NTSC;

	/* Vsync IRQ at start of Vsync at first */
	ctrl1 |= TVE200_VSTSTYPE_VSYNC;

	if (connector->display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_NEGEDGE)
		ctrl1 |= TVE200_CTRL_TVCLKP;

	if ((mode->hdisplay == 352 && mode->vdisplay == 240) || /* SIF(525) */
	    (mode->hdisplay == 352 && mode->vdisplay == 288)) { /* CIF(625) */
		ctrl1 |= TVE200_CTRL_IPRESOL_CIF;
		dev_info(drm->dev, "CIF mode\n");
	} else if (mode->hdisplay == 640 && mode->vdisplay == 480) {
		ctrl1 |= TVE200_CTRL_IPRESOL_VGA;
		dev_info(drm->dev, "VGA mode\n");
	} else if ((mode->hdisplay == 720 && mode->vdisplay == 480) ||
		   (mode->hdisplay == 720 && mode->vdisplay == 576)) {
		ctrl1 |= TVE200_CTRL_IPRESOL_D1;
		dev_info(drm->dev, "D1 mode\n");
	}

	if (format & DRM_FORMAT_BIG_ENDIAN) {
		ctrl1 |= TVE200_CTRL_BBBP;
		format &= ~DRM_FORMAT_BIG_ENDIAN;
	}

	switch (format) {
	case DRM_FORMAT_XRGB8888:
		ctrl1 |= TVE200_IPDMOD_RGB888;
		break;
	case DRM_FORMAT_RGB565:
		ctrl1 |= TVE200_IPDMOD_RGB565;
		break;
	case DRM_FORMAT_XRGB1555:
		ctrl1 |= TVE200_IPDMOD_RGB555;
		break;
	case DRM_FORMAT_XBGR8888:
		ctrl1 |= TVE200_IPDMOD_RGB888 | TVE200_BGR;
		break;
	case DRM_FORMAT_BGR565:
		ctrl1 |= TVE200_IPDMOD_RGB565 | TVE200_BGR;
		break;
	case DRM_FORMAT_XBGR1555:
		ctrl1 |= TVE200_IPDMOD_RGB555 | TVE200_BGR;
		break;
	case DRM_FORMAT_YUYV:
		ctrl1 |= TVE200_IPDMOD_YUV422;
		ctrl1 |= TVE200_CTRL_YCBCRODR_CR0Y1CB0Y0;
		break;
	case DRM_FORMAT_YVYU:
		ctrl1 |= TVE200_IPDMOD_YUV422;
		ctrl1 |= TVE200_CTRL_YCBCRODR_CB0Y1CR0Y0;
		break;
	case DRM_FORMAT_UYVY:
		ctrl1 |= TVE200_IPDMOD_YUV422;
		ctrl1 |= TVE200_CTRL_YCBCRODR_Y1CR0Y0CB0;
		break;
	case DRM_FORMAT_VYUY:
		ctrl1 |= TVE200_IPDMOD_YUV422;
		ctrl1 |= TVE200_CTRL_YCBCRODR_Y1CB0Y0CR0;
		break;
	case DRM_FORMAT_YUV420:
		ctrl1 |= TVE200_CTRL_YUV420;
		ctrl1 |= TVE200_IPDMOD_YUV420;
		break;
	default:
		dev_err(drm->dev, "Unknown FB format 0x%08x\n",
			fb->format->format);
		break;
	}

	ctrl1 |= TVE200_TVEEN;

	/* Turn it on */
	writel(ctrl1, priv->regs + TVE200_CTRL);

	drm_crtc_vblank_on(crtc);
}

static void tve200_display_disable(struct drm_simple_display_pipe *pipe)
{
	struct drm_crtc *crtc = &pipe->crtc;
	struct drm_device *drm = crtc->dev;
	struct tve200_drm_dev_private *priv = drm->dev_private;

	drm_crtc_vblank_off(crtc);

	/* Disable put into reset and Power Down */
	writel(0, priv->regs + TVE200_CTRL);
	writel(TVE200_CTRL_4_RESET, priv->regs + TVE200_CTRL_4);

	clk_disable_unprepare(priv->clk);
}

static void tve200_display_update(struct drm_simple_display_pipe *pipe,
				 struct drm_plane_state *old_pstate)
{
	struct drm_crtc *crtc = &pipe->crtc;
	struct drm_device *drm = crtc->dev;
	struct tve200_drm_dev_private *priv = drm->dev_private;
	struct drm_pending_vblank_event *event = crtc->state->event;
	struct drm_plane *plane = &pipe->plane;
	struct drm_plane_state *pstate = plane->state;
	struct drm_framebuffer *fb = pstate->fb;

	if (fb) {
		/* For RGB, the Y component is used as base address */
		writel(drm_fb_cma_get_gem_addr(fb, pstate, 0),
		       priv->regs + TVE200_Y_FRAME_BASE_ADDR);

		/* For three plane YUV we need two more addresses */
		if (fb->format->format == DRM_FORMAT_YUV420) {
			writel(drm_fb_cma_get_gem_addr(fb, pstate, 1),
			       priv->regs + TVE200_U_FRAME_BASE_ADDR);
			writel(drm_fb_cma_get_gem_addr(fb, pstate, 2),
			       priv->regs + TVE200_V_FRAME_BASE_ADDR);
		}
	}

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

		spin_lock_irq(&crtc->dev->event_lock);
		if (crtc->state->active && 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 int tve200_display_enable_vblank(struct drm_simple_display_pipe *pipe)
{
	struct drm_crtc *crtc = &pipe->crtc;
	struct drm_device *drm = crtc->dev;
	struct tve200_drm_dev_private *priv = drm->dev_private;

	/* Clear any IRQs and enable */
	writel(0xFF, priv->regs + TVE200_INT_CLR);
	writel(TVE200_INT_V_STATUS, priv->regs + TVE200_INT_EN);
	return 0;
}

static void tve200_display_disable_vblank(struct drm_simple_display_pipe *pipe)
{
	struct drm_crtc *crtc = &pipe->crtc;
	struct drm_device *drm = crtc->dev;
	struct tve200_drm_dev_private *priv = drm->dev_private;

	writel(0, priv->regs + TVE200_INT_EN);
}

static const struct drm_simple_display_pipe_funcs tve200_display_funcs = {
	.check = tve200_display_check,
	.enable = tve200_display_enable,
	.disable = tve200_display_disable,
	.update = tve200_display_update,
	.prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
	.enable_vblank = tve200_display_enable_vblank,
	.disable_vblank = tve200_display_disable_vblank,
};

int tve200_display_init(struct drm_device *drm)
{
	struct tve200_drm_dev_private *priv = drm->dev_private;
	int ret;
	static const u32 formats[] = {
		DRM_FORMAT_XRGB8888,
		DRM_FORMAT_XBGR8888,
		DRM_FORMAT_RGB565,
		DRM_FORMAT_BGR565,
		DRM_FORMAT_XRGB1555,
		DRM_FORMAT_XBGR1555,
		/*
		 * The controller actually supports any YCbCr ordering,
		 * for packed YCbCr. This just lists the orderings that
		 * DRM supports.
		 */
		DRM_FORMAT_YUYV,
		DRM_FORMAT_YVYU,
		DRM_FORMAT_UYVY,
		DRM_FORMAT_VYUY,
		/* This uses three planes */
		DRM_FORMAT_YUV420,
	};

	ret = drm_simple_display_pipe_init(drm, &priv->pipe,
					   &tve200_display_funcs,
					   formats, ARRAY_SIZE(formats),
					   NULL,
					   priv->connector);
	if (ret)
		return ret;

	return 0;
}