/*
 * SuperH Mobile MERAM Driver for SuperH Mobile LCDC Driver
 *
 * Copyright (c) 2011	Damian Hobson-Garcia <dhobsong@igel.co.jp>
 *                      Takanari Hayama <taki@igel.co.jp>
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/platform_device.h>

#include "sh_mobile_meram.h"

/* meram registers */
#define MExxCTL 0x0
#define MExxBSIZE 0x4
#define MExxMNCF 0x8
#define MExxSARA 0x10
#define MExxSARB 0x14
#define MExxSBSIZE 0x18

#define MERAM_MExxCTL_VAL(ctl, next_icb, addr)	\
	((ctl) | (((next_icb) & 0x1f) << 11) | (((addr) & 0x7ff) << 16))
#define	MERAM_MExxBSIZE_VAL(a, b, c) \
	(((a) << 28) | ((b) << 16) | (c))

#define MEVCR1 0x4
#define MEACTS 0x10
#define MEQSEL1 0x40
#define MEQSEL2 0x44

/* settings */
#define MERAM_SEC_LINE 15
#define MERAM_LINE_WIDTH 2048

/*
 * MERAM/ICB access functions
 */

#define MERAM_ICB_OFFSET(base, idx, off)	\
	((base) + (0x400 + ((idx) * 0x20) + (off)))

static inline void meram_write_icb(void __iomem *base, int idx, int off,
	unsigned long val)
{
	iowrite32(val, MERAM_ICB_OFFSET(base, idx, off));
}

static inline unsigned long meram_read_icb(void __iomem *base, int idx, int off)
{
	return ioread32(MERAM_ICB_OFFSET(base, idx, off));
}

static inline void meram_write_reg(void __iomem *base, int off,
		unsigned long val)
{
	iowrite32(val, base + off);
}

static inline unsigned long meram_read_reg(void __iomem *base, int off)
{
	return ioread32(base + off);
}

/*
 * register ICB
 */

#define MERAM_CACHE_START(p)	 ((p) >> 16)
#define MERAM_CACHE_END(p)	 ((p) & 0xffff)
#define MERAM_CACHE_SET(o, s)	 ((((o) & 0xffff) << 16) | \
				  (((o) + (s) - 1) & 0xffff))

/*
 * check if there's no overlaps in MERAM allocation.
 */

static inline int meram_check_overlap(struct sh_mobile_meram_priv *priv,
				      struct sh_mobile_meram_icb *new)
{
	int i;
	int used_start, used_end, meram_start, meram_end;

	/* valid ICB? */
	if (new->marker_icb & ~0x1f || new->cache_icb & ~0x1f)
		return 1;

	if (test_bit(new->marker_icb, &priv->used_icb) ||
			test_bit(new->cache_icb,  &priv->used_icb))
		return  1;

	for (i = 0; i < priv->used_meram_cache_regions; i++) {
		used_start = MERAM_CACHE_START(priv->used_meram_cache[i]);
		used_end   = MERAM_CACHE_END(priv->used_meram_cache[i]);
		meram_start = new->meram_offset;
		meram_end   = new->meram_offset + new->meram_size;

		if ((meram_start >= used_start && meram_start < used_end) ||
			(meram_end > used_start && meram_end < used_end))
			return 1;
	}

	return 0;
}

/*
 * mark the specified ICB as used
 */

static inline void meram_mark(struct sh_mobile_meram_priv *priv,
			      struct sh_mobile_meram_icb *new)
{
	int n;

	if (new->marker_icb < 0 || new->cache_icb < 0)
		return;

	__set_bit(new->marker_icb, &priv->used_icb);
	__set_bit(new->cache_icb, &priv->used_icb);

	n = priv->used_meram_cache_regions;

	priv->used_meram_cache[n] = MERAM_CACHE_SET(new->meram_offset,
						    new->meram_size);

	priv->used_meram_cache_regions++;
}

/*
 * unmark the specified ICB as used
 */

static inline void meram_unmark(struct sh_mobile_meram_priv *priv,
				struct sh_mobile_meram_icb *icb)
{
	int i;
	unsigned long pattern;

	if (icb->marker_icb < 0 || icb->cache_icb < 0)
		return;

	__clear_bit(icb->marker_icb, &priv->used_icb);
	__clear_bit(icb->cache_icb, &priv->used_icb);

	pattern = MERAM_CACHE_SET(icb->meram_offset, icb->meram_size);
	for (i = 0; i < priv->used_meram_cache_regions; i++) {
		if (priv->used_meram_cache[i] == pattern) {
			while (i < priv->used_meram_cache_regions - 1) {
				priv->used_meram_cache[i] =
					priv->used_meram_cache[i + 1] ;
				i++;
			}
			priv->used_meram_cache[i] = 0;
			priv->used_meram_cache_regions--;
			break;
		}
	}
}

/*
 * is this a YCbCr(NV12, NV16 or NV24) colorspace
 */
static inline int is_nvcolor(int cspace)
{
	if (cspace == SH_MOBILE_MERAM_PF_NV ||
			cspace == SH_MOBILE_MERAM_PF_NV24)
		return 1;
	return 0;
}

/*
 * set the next address to fetch
 */
static inline void meram_set_next_addr(struct sh_mobile_meram_priv *priv,
				       struct sh_mobile_meram_cfg *cfg,
				       unsigned long base_addr_y,
				       unsigned long base_addr_c)
{
	unsigned long target;

	target = (cfg->current_reg) ? MExxSARA : MExxSARB;
	cfg->current_reg ^= 1;

	/* set the next address to fetch */
	meram_write_icb(priv->base, cfg->icb[0].cache_icb,  target,
			base_addr_y);
	meram_write_icb(priv->base, cfg->icb[0].marker_icb, target,
			base_addr_y + cfg->icb[0].cache_unit);

	if (is_nvcolor(cfg->pixelformat)) {
		meram_write_icb(priv->base, cfg->icb[1].cache_icb,  target,
				base_addr_c);
		meram_write_icb(priv->base, cfg->icb[1].marker_icb, target,
				base_addr_c + cfg->icb[1].cache_unit);
	}
}

/*
 * get the next ICB address
 */
static inline void meram_get_next_icb_addr(struct sh_mobile_meram_info *pdata,
					   struct sh_mobile_meram_cfg *cfg,
					   unsigned long *icb_addr_y,
					   unsigned long *icb_addr_c)
{
	unsigned long icb_offset;

	if (pdata->addr_mode == SH_MOBILE_MERAM_MODE0)
		icb_offset = 0x80000000 | (cfg->current_reg << 29);
	else
		icb_offset = 0xc0000000 | (cfg->current_reg << 23);

	*icb_addr_y = icb_offset | (cfg->icb[0].marker_icb << 24);
	if (is_nvcolor(cfg->pixelformat))
		*icb_addr_c = icb_offset | (cfg->icb[1].marker_icb << 24);
}

#define MERAM_CALC_BYTECOUNT(x, y) \
	(((x) * (y) + (MERAM_LINE_WIDTH - 1)) & ~(MERAM_LINE_WIDTH - 1))

/*
 * initialize MERAM
 */

static int meram_init(struct sh_mobile_meram_priv *priv,
		      struct sh_mobile_meram_icb *icb,
		      int xres, int yres, int *out_pitch)
{
	unsigned long total_byte_count = MERAM_CALC_BYTECOUNT(xres, yres);
	unsigned long bnm;
	int lcdc_pitch, xpitch, line_cnt;
	int save_lines;

	/* adjust pitch to 1024, 2048, 4096 or 8192 */
	lcdc_pitch = (xres - 1) | 1023;
	lcdc_pitch = lcdc_pitch | (lcdc_pitch >> 1);
	lcdc_pitch = lcdc_pitch | (lcdc_pitch >> 2);
	lcdc_pitch += 1;

	/* derive settings */
	if (lcdc_pitch == 8192 && yres >= 1024) {
		lcdc_pitch = xpitch = MERAM_LINE_WIDTH;
		line_cnt = total_byte_count >> 11;
		*out_pitch = xres;
		save_lines = (icb->meram_size / 16 / MERAM_SEC_LINE);
		save_lines *= MERAM_SEC_LINE;
	} else {
		xpitch = xres;
		line_cnt = yres;
		*out_pitch = lcdc_pitch;
		save_lines = icb->meram_size / (lcdc_pitch >> 10) / 2;
		save_lines &= 0xff;
	}
	bnm = (save_lines - 1) << 16;

	/* TODO: we better to check if we have enough MERAM buffer size */

	/* set up ICB */
	meram_write_icb(priv->base, icb->cache_icb,  MExxBSIZE,
			MERAM_MExxBSIZE_VAL(0x0, line_cnt - 1, xpitch - 1));
	meram_write_icb(priv->base, icb->marker_icb, MExxBSIZE,
			MERAM_MExxBSIZE_VAL(0xf, line_cnt - 1, xpitch - 1));

	meram_write_icb(priv->base, icb->cache_icb,  MExxMNCF, bnm);
	meram_write_icb(priv->base, icb->marker_icb, MExxMNCF, bnm);

	meram_write_icb(priv->base, icb->cache_icb,  MExxSBSIZE, xpitch);
	meram_write_icb(priv->base, icb->marker_icb, MExxSBSIZE, xpitch);

	/* save a cache unit size */
	icb->cache_unit = xres * save_lines;

	/*
	 * Set MERAM for framebuffer
	 *
	 * 0x70f:  WD = 0x3, WS=0x1, CM=0x1, MD=FB mode
	 * we also chain the cache_icb and the marker_icb.
	 * we also split the allocated MERAM buffer between two ICBs.
	 */
	meram_write_icb(priv->base, icb->cache_icb, MExxCTL,
			MERAM_MExxCTL_VAL(0x70f, icb->marker_icb,
					  icb->meram_offset));
	meram_write_icb(priv->base, icb->marker_icb, MExxCTL,
			MERAM_MExxCTL_VAL(0x70f, icb->cache_icb,
					  icb->meram_offset +
					  icb->meram_size / 2));

	return 0;
}

static void meram_deinit(struct sh_mobile_meram_priv *priv,
			struct sh_mobile_meram_icb *icb)
{
	/* disable ICB */
	meram_write_icb(priv->base, icb->cache_icb,  MExxCTL, 0);
	meram_write_icb(priv->base, icb->marker_icb, MExxCTL, 0);
	icb->cache_unit = 0;
}

/*
 * register the ICB
 */

static int sh_mobile_meram_register(struct sh_mobile_meram_info *pdata,
				    struct sh_mobile_meram_cfg *cfg,
				    int xres, int yres, int pixelformat,
				    unsigned long base_addr_y,
				    unsigned long base_addr_c,
				    unsigned long *icb_addr_y,
				    unsigned long *icb_addr_c,
				    int *pitch)
{
	struct platform_device *pdev;
	struct sh_mobile_meram_priv *priv;
	int n, out_pitch;
	int error = 0;

	if (!pdata || !pdata->priv || !pdata->pdev || !cfg)
		return -EINVAL;

	if (pixelformat != SH_MOBILE_MERAM_PF_NV &&
	    pixelformat != SH_MOBILE_MERAM_PF_NV24 &&
	    pixelformat != SH_MOBILE_MERAM_PF_RGB)
		return -EINVAL;

	priv = pdata->priv;
	pdev = pdata->pdev;

	dev_dbg(&pdev->dev, "registering %dx%d (%s) (y=%08lx, c=%08lx)",
		xres, yres, (!pixelformat) ? "yuv" : "rgb",
		base_addr_y, base_addr_c);

	mutex_lock(&priv->lock);

	/* we can't handle wider than 8192px */
	if (xres > 8192) {
		dev_err(&pdev->dev, "width exceeding the limit (> 8192).");
		error = -EINVAL;
		goto err;
	}

	if (priv->used_meram_cache_regions + 2 > SH_MOBILE_MERAM_ICB_NUM) {
		dev_err(&pdev->dev, "no more ICB available.");
		error = -EINVAL;
		goto err;
	}

	/* do we have at least one ICB config? */
	if (cfg->icb[0].marker_icb < 0 || cfg->icb[0].cache_icb < 0) {
		dev_err(&pdev->dev, "at least one ICB is required.");
		error = -EINVAL;
		goto err;
	}

	/* make sure that there's no overlaps */
	if (meram_check_overlap(priv, &cfg->icb[0])) {
		dev_err(&pdev->dev, "conflicting config detected.");
		error = -EINVAL;
		goto err;
	}
	n = 1;

	/* do the same if we have the second ICB set */
	if (cfg->icb[1].marker_icb >= 0 && cfg->icb[1].cache_icb >= 0) {
		if (meram_check_overlap(priv, &cfg->icb[1])) {
			dev_err(&pdev->dev, "conflicting config detected.");
			error = -EINVAL;
			goto err;
		}
		n = 2;
	}

	if (is_nvcolor(pixelformat) && n != 2) {
		dev_err(&pdev->dev, "requires two ICB sets for planar Y/C.");
		error =  -EINVAL;
		goto err;
	}

	/* we now register the ICB */
	cfg->pixelformat = pixelformat;
	meram_mark(priv, &cfg->icb[0]);
	if (is_nvcolor(pixelformat))
		meram_mark(priv, &cfg->icb[1]);

	/* initialize MERAM */
	meram_init(priv, &cfg->icb[0], xres, yres, &out_pitch);
	*pitch = out_pitch;
	if (pixelformat == SH_MOBILE_MERAM_PF_NV)
		meram_init(priv, &cfg->icb[1], xres, (yres + 1) / 2,
			&out_pitch);
	else if (pixelformat == SH_MOBILE_MERAM_PF_NV24)
		meram_init(priv, &cfg->icb[1], 2 * xres, (yres + 1) / 2,
			&out_pitch);

	cfg->current_reg = 1;
	meram_set_next_addr(priv, cfg, base_addr_y, base_addr_c);
	meram_get_next_icb_addr(pdata, cfg, icb_addr_y, icb_addr_c);

	dev_dbg(&pdev->dev, "registered - can access via y=%08lx, c=%08lx",
		*icb_addr_y, *icb_addr_c);

err:
	mutex_unlock(&priv->lock);
	return error;
}

static int sh_mobile_meram_unregister(struct sh_mobile_meram_info *pdata,
				      struct sh_mobile_meram_cfg *cfg)
{
	struct sh_mobile_meram_priv *priv;

	if (!pdata || !pdata->priv || !cfg)
		return -EINVAL;

	priv = pdata->priv;

	mutex_lock(&priv->lock);

	/* deinit & unmark */
	if (is_nvcolor(cfg->pixelformat)) {
		meram_deinit(priv, &cfg->icb[1]);
		meram_unmark(priv, &cfg->icb[1]);
	}
	meram_deinit(priv, &cfg->icb[0]);
	meram_unmark(priv, &cfg->icb[0]);

	mutex_unlock(&priv->lock);

	return 0;
}

static int sh_mobile_meram_update(struct sh_mobile_meram_info *pdata,
				  struct sh_mobile_meram_cfg *cfg,
				  unsigned long base_addr_y,
				  unsigned long base_addr_c,
				  unsigned long *icb_addr_y,
				  unsigned long *icb_addr_c)
{
	struct sh_mobile_meram_priv *priv;

	if (!pdata || !pdata->priv || !cfg)
		return -EINVAL;

	priv = pdata->priv;

	mutex_lock(&priv->lock);

	meram_set_next_addr(priv, cfg, base_addr_y, base_addr_c);
	meram_get_next_icb_addr(pdata, cfg, icb_addr_y, icb_addr_c);

	mutex_unlock(&priv->lock);

	return 0;
}

static struct sh_mobile_meram_ops sh_mobile_meram_ops = {
	.module			= THIS_MODULE,
	.meram_register		= sh_mobile_meram_register,
	.meram_unregister	= sh_mobile_meram_unregister,
	.meram_update		= sh_mobile_meram_update,
};

/*
 * initialize MERAM
 */

static int sh_mobile_meram_remove(struct platform_device *pdev);

static int __devinit sh_mobile_meram_probe(struct platform_device *pdev)
{
	struct sh_mobile_meram_priv *priv;
	struct sh_mobile_meram_info *pdata = pdev->dev.platform_data;
	struct resource *res;
	int error;

	if (!pdata) {
		dev_err(&pdev->dev, "no platform data defined\n");
		return -EINVAL;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&pdev->dev, "cannot get platform resources\n");
		return -ENOENT;
	}

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv) {
		dev_err(&pdev->dev, "cannot allocate device data\n");
		return -ENOMEM;
	}

	platform_set_drvdata(pdev, priv);

	/* initialize private data */
	mutex_init(&priv->lock);
	priv->base = ioremap_nocache(res->start, resource_size(res));
	if (!priv->base) {
		dev_err(&pdev->dev, "ioremap failed\n");
		error = -EFAULT;
		goto err;
	}
	pdata->ops = &sh_mobile_meram_ops;
	pdata->priv = priv;
	pdata->pdev = pdev;

	/* initialize ICB addressing mode */
	if (pdata->addr_mode == SH_MOBILE_MERAM_MODE1)
		meram_write_reg(priv->base, MEVCR1, 1 << 29);

	dev_info(&pdev->dev, "sh_mobile_meram initialized.");

	return 0;

err:
	sh_mobile_meram_remove(pdev);

	return error;
}


static int sh_mobile_meram_remove(struct platform_device *pdev)
{
	struct sh_mobile_meram_priv *priv = platform_get_drvdata(pdev);

	if (priv->base)
		iounmap(priv->base);

	mutex_destroy(&priv->lock);

	kfree(priv);

	return 0;
}

static struct platform_driver sh_mobile_meram_driver = {
	.driver	= {
		.name		= "sh_mobile_meram",
		.owner		= THIS_MODULE,
	},
	.probe		= sh_mobile_meram_probe,
	.remove		= sh_mobile_meram_remove,
};

static int __init sh_mobile_meram_init(void)
{
	return platform_driver_register(&sh_mobile_meram_driver);
}

static void __exit sh_mobile_meram_exit(void)
{
	platform_driver_unregister(&sh_mobile_meram_driver);
}

module_init(sh_mobile_meram_init);
module_exit(sh_mobile_meram_exit);

MODULE_DESCRIPTION("SuperH Mobile MERAM driver");
MODULE_AUTHOR("Damian Hobson-Garcia / Takanari Hayama");
MODULE_LICENSE("GPL v2");