/*
 * (C) COPYRIGHT 2012-2013 ARM Limited. All rights reserved.
 *
 * Parts of this file were based on sources as follows:
 *
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
 * Copyright (C) 2011 Texas Instruments
 *
 * 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.
 *
 */

/**
 * DOC: ARM PrimeCell PL111 CLCD Driver
 *
 * The PL111 is a simple LCD controller that can support TFT and STN
 * displays.  This driver exposes a standard KMS interface for them.
 *
 * This driver uses the same Device Tree binding as the fbdev CLCD
 * driver.  While the fbdev driver supports panels that may be
 * connected to the CLCD internally to the CLCD driver, in DRM the
 * panels get split out to drivers/gpu/drm/panels/.  This means that,
 * in converting from using fbdev to using DRM, you also need to write
 * a panel driver (which may be as simple as an entry in
 * panel-simple.c).
 *
 * The driver currently doesn't expose the cursor.  The DRM API for
 * cursors requires support for 64x64 ARGB8888 cursor images, while
 * the hardware can only support 64x64 monochrome with masking
 * cursors.  While one could imagine trying to hack something together
 * to look at the ARGB8888 and program reasonable in monochrome, we
 * just don't expose the cursor at all instead, and leave cursor
 * support to the X11 software cursor layer.
 *
 * TODO:
 *
 * - Fix race between setting plane base address and getting IRQ for
 *   vsync firing the pageflip completion.
 *
 * - Use the "max-memory-bandwidth" DT property to filter the
 *   supported formats.
 *
 * - Read back hardware state at boot to skip reprogramming the
 *   hardware when doing a no-op modeset.
 *
 * - Use the CLKSEL bit to support switching between the two external
 *   clock parents.
 */

#include <linux/amba/bus.h>
#include <linux/amba/clcd-regs.h>
#include <linux/version.h>
#include <linux/shmem_fs.h>
#include <linux/dma-buf.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_graph.h>

#include <drm/drmP.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_fb_cma_helper.h>
#include <drm/drm_of.h>
#include <drm/drm_bridge.h>
#include <drm/drm_panel.h>

#include "pl111_drm.h"
#include "pl111_versatile.h"

#define DRIVER_DESC      "DRM module for PL111"

static const struct drm_mode_config_funcs mode_config_funcs = {
        .fb_create = drm_gem_fb_create,
        .atomic_check = drm_atomic_helper_check,
        .atomic_commit = drm_atomic_helper_commit,
};

static int pl111_modeset_init(struct drm_device *dev)
{
        struct drm_mode_config *mode_config;
        struct pl111_drm_dev_private *priv = dev->dev_private;
        struct device_node *np = dev->dev->of_node;
        struct device_node *remote;
        struct drm_panel *panel = NULL;
        struct drm_bridge *bridge = NULL;
        bool defer = false;
        int ret = 0;
        int i;

        drm_mode_config_init(dev);
        mode_config = &dev->mode_config;
        mode_config->funcs = &mode_config_funcs;
        mode_config->min_width = 1;
        mode_config->max_width = 1024;
        mode_config->min_height = 1;
        mode_config->max_height = 768;

        i = 0;
        for_each_endpoint_of_node(np, remote) {
                struct drm_panel *tmp_panel;
                struct drm_bridge *tmp_bridge;

                dev_dbg(dev->dev, "checking endpoint %d\n", i);

                ret = drm_of_find_panel_or_bridge(dev->dev->of_node,
                                                  0, i,
                                                  &tmp_panel,
                                                  &tmp_bridge);
                if (ret) {
                        if (ret == -EPROBE_DEFER) {
                                /*
                                 * Something deferred, but that is often just
                                 * another way of saying -ENODEV, but let's
                                 * cast a vote for later deferral.
                                 */
                                defer = true;
                        } else if (ret != -ENODEV) {
                                /* Continue, maybe something else is working */
                                dev_err(dev->dev,
                                        "endpoint %d returns %d\n", i, ret);
                        }
                }

                if (tmp_panel) {
                        dev_info(dev->dev,
                                 "found panel on endpoint %d\n", i);
                        panel = tmp_panel;
                }
                if (tmp_bridge) {
                        dev_info(dev->dev,
                                 "found bridge on endpoint %d\n", i);
                        bridge = tmp_bridge;
                }

                i++;
        }

        /*
         * If we can't find neither panel nor bridge on any of the
         * endpoints, and any of them retured -EPROBE_DEFER, then
         * let's defer this driver too.
         */
        if ((!panel && !bridge) && defer)
                return -EPROBE_DEFER;

        if (panel) {
                bridge = drm_panel_bridge_add(panel,
                                              DRM_MODE_CONNECTOR_Unknown);
                if (IS_ERR(bridge)) {
                        ret = PTR_ERR(bridge);
                        goto out_config;
                }
        } else if (bridge) {
                dev_info(dev->dev, "Using non-panel bridge\n");
        } else {
                dev_err(dev->dev, "No bridge, exiting\n");
                return -ENODEV;
        }

        priv->bridge = bridge;
        if (panel) {
                priv->panel = panel;
                priv->connector = panel->connector;
        }

        ret = pl111_display_init(dev);
        if (ret != 0) {
                dev_err(dev->dev, "Failed to init display\n");
                goto out_bridge;
        }

        ret = drm_simple_display_pipe_attach_bridge(&priv->pipe,
                                                    bridge);
        if (ret)
                return ret;

        if (!priv->variant->broken_vblank) {
                ret = drm_vblank_init(dev, 1);
                if (ret != 0) {
                        dev_err(dev->dev, "Failed to init vblank\n");
                        goto out_bridge;
                }
        }

        drm_mode_config_reset(dev);

        drm_fb_cma_fbdev_init(dev, priv->variant->fb_bpp, 0);

        drm_kms_helper_poll_init(dev);

        goto finish;

out_bridge:
        if (panel)
                drm_panel_bridge_remove(bridge);
out_config:
        drm_mode_config_cleanup(dev);
finish:
        return ret;
}

DEFINE_DRM_GEM_CMA_FOPS(drm_fops);

static struct drm_driver pl111_drm_driver = {
        .driver_features =
                DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME | DRIVER_ATOMIC,
        .lastclose = drm_fb_helper_lastclose,
        .ioctls = NULL,
        .fops = &drm_fops,
        .name = "pl111",
        .desc = DRIVER_DESC,
        .date = "20170317",
        .major = 1,
        .minor = 0,
        .patchlevel = 0,
        .dumb_create = drm_gem_cma_dumb_create,
        .gem_free_object_unlocked = drm_gem_cma_free_object,
        .gem_vm_ops = &drm_gem_cma_vm_ops,
        .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
        .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
        .gem_prime_import = drm_gem_prime_import,
        .gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
        .gem_prime_export = drm_gem_prime_export,
        .gem_prime_get_sg_table = drm_gem_cma_prime_get_sg_table,

#if defined(CONFIG_DEBUG_FS)
        .debugfs_init = pl111_debugfs_init,
#endif
};

static int pl111_amba_probe(struct amba_device *amba_dev,
                            const struct amba_id *id)
{
        struct device *dev = &amba_dev->dev;
        struct pl111_drm_dev_private *priv;
        const struct pl111_variant_data *variant = id->data;
        struct drm_device *drm;
        int ret;

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        drm = drm_dev_alloc(&pl111_drm_driver, dev);
        if (IS_ERR(drm))
                return PTR_ERR(drm);
        amba_set_drvdata(amba_dev, drm);
        priv->drm = drm;
        drm->dev_private = priv;
        priv->variant = variant;

        if (of_property_read_u32(dev->of_node, "max-memory-bandwidth",
                                 &priv->memory_bw)) {
                dev_info(dev, "no max memory bandwidth specified, assume unlimited\n");
                priv->memory_bw = 0;
        }

        /* The two variants swap this register */
        if (variant->is_pl110) {
                priv->ienb = CLCD_PL110_IENB;
                priv->ctrl = CLCD_PL110_CNTL;
        } else {
                priv->ienb = CLCD_PL111_IENB;
                priv->ctrl = CLCD_PL111_CNTL;
        }

        priv->regs = devm_ioremap_resource(dev, &amba_dev->res);
        if (IS_ERR(priv->regs)) {
                dev_err(dev, "%s failed mmio\n", __func__);
                return PTR_ERR(priv->regs);
        }

        /* This may override some variant settings */
        ret = pl111_versatile_init(dev, priv);
        if (ret)
                goto dev_unref;

        /* turn off interrupts before requesting the irq */
        writel(0, priv->regs + priv->ienb);

        ret = devm_request_irq(dev, amba_dev->irq[0], pl111_irq, 0,
                               variant->name, priv);
        if (ret != 0) {
                dev_err(dev, "%s failed irq %d\n", __func__, ret);
                return ret;
        }

        ret = pl111_modeset_init(drm);
        if (ret != 0)
                goto dev_unref;

        ret = drm_dev_register(drm, 0);
        if (ret < 0)
                goto dev_unref;

        return 0;

dev_unref:
        drm_dev_unref(drm);
        return ret;
}

static int pl111_amba_remove(struct amba_device *amba_dev)
{
        struct drm_device *drm = amba_get_drvdata(amba_dev);
        struct pl111_drm_dev_private *priv = drm->dev_private;

        drm_dev_unregister(drm);
        drm_fb_cma_fbdev_fini(drm);
        if (priv->panel)
                drm_panel_bridge_remove(priv->bridge);
        drm_mode_config_cleanup(drm);
        drm_dev_unref(drm);

        return 0;
}

/*
 * This early variant lacks the 565 and 444 pixel formats.
 */
static const u32 pl110_pixel_formats[] = {
        DRM_FORMAT_ABGR8888,
        DRM_FORMAT_XBGR8888,
        DRM_FORMAT_ARGB8888,
        DRM_FORMAT_XRGB8888,
        DRM_FORMAT_ABGR1555,
        DRM_FORMAT_XBGR1555,
        DRM_FORMAT_ARGB1555,
        DRM_FORMAT_XRGB1555,
};

static const struct pl111_variant_data pl110_variant = {
        .name = "PL110",
        .is_pl110 = true,
        .formats = pl110_pixel_formats,
        .nformats = ARRAY_SIZE(pl110_pixel_formats),
        .fb_bpp = 16,
};

/* RealView, Versatile Express etc use this modern variant */
static const u32 pl111_pixel_formats[] = {
        DRM_FORMAT_ABGR8888,
        DRM_FORMAT_XBGR8888,
        DRM_FORMAT_ARGB8888,
        DRM_FORMAT_XRGB8888,
        DRM_FORMAT_BGR565,
        DRM_FORMAT_RGB565,
        DRM_FORMAT_ABGR1555,
        DRM_FORMAT_XBGR1555,
        DRM_FORMAT_ARGB1555,
        DRM_FORMAT_XRGB1555,
        DRM_FORMAT_ABGR4444,
        DRM_FORMAT_XBGR4444,
        DRM_FORMAT_ARGB4444,
        DRM_FORMAT_XRGB4444,
};

static const struct pl111_variant_data pl111_variant = {
        .name = "PL111",
        .formats = pl111_pixel_formats,
        .nformats = ARRAY_SIZE(pl111_pixel_formats),
        .fb_bpp = 32,
};

static const struct amba_id pl111_id_table[] = {
        {
                .id = 0x00041110,
                .mask = 0x000fffff,
                .data = (void*)&pl110_variant,
        },
        {
                .id = 0x00041111,
                .mask = 0x000fffff,
                .data = (void*)&pl111_variant,
        },
        {0, 0},
};

static struct amba_driver pl111_amba_driver __maybe_unused = {
        .drv = {
                .name = "drm-clcd-pl111",
        },
        .probe = pl111_amba_probe,
        .remove = pl111_amba_remove,
        .id_table = pl111_id_table,
};

#ifdef CONFIG_ARM_AMBA
module_amba_driver(pl111_amba_driver);
#endif

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("ARM Ltd.");
MODULE_LICENSE("GPL");