// SPDX-License-Identifier: GPL-2.0-only
/*
 * VRFB Rotation Engine
 *
 * Copyright (C) 2009 Nokia Corporation
 * Author: Tomi Valkeinen <tomi.valkeinen@nokia.com>
 */

/*#define DEBUG*/

#include <linux/err.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>

#include <video/omapvrfb.h>

#ifdef DEBUG
#define DBG(format, ...) pr_debug("VRFB: " format, ## __VA_ARGS__)
#else
#define DBG(format, ...)
#endif

#define SMS_ROT_CONTROL(context)        (0x0 + 0x10 * context)
#define SMS_ROT_SIZE(context)           (0x4 + 0x10 * context)
#define SMS_ROT_PHYSICAL_BA(context)    (0x8 + 0x10 * context)
#define SMS_ROT_VIRT_BASE(rot)          (0x1000000 * (rot))

#define OMAP_VRFB_SIZE                  (2048 * 2048 * 4)

#define VRFB_PAGE_WIDTH_EXP     5 /* Assuming SDRAM pagesize= 1024 */
#define VRFB_PAGE_HEIGHT_EXP    5 /* 1024 = 2^5 * 2^5 */
#define VRFB_PAGE_WIDTH         (1 << VRFB_PAGE_WIDTH_EXP)
#define VRFB_PAGE_HEIGHT        (1 << VRFB_PAGE_HEIGHT_EXP)
#define SMS_IMAGEHEIGHT_OFFSET  16
#define SMS_IMAGEWIDTH_OFFSET   0
#define SMS_PH_OFFSET           8
#define SMS_PW_OFFSET           4
#define SMS_PS_OFFSET           0

/* bitmap of reserved contexts */
static unsigned long ctx_map;

struct vrfb_ctx {
        u32 base;
        u32 physical_ba;
        u32 control;
        u32 size;
};

static DEFINE_MUTEX(ctx_lock);

/*
 * Access to this happens from client drivers or the PM core after wake-up.
 * For the first case we require locking at the driver level, for the second
 * we don't need locking, since no drivers will run until after the wake-up
 * has finished.
 */

static void __iomem *vrfb_base;

static int num_ctxs;
static struct vrfb_ctx *ctxs;

static bool vrfb_loaded;

static void omap2_sms_write_rot_control(u32 val, unsigned ctx)
{
        __raw_writel(val, vrfb_base + SMS_ROT_CONTROL(ctx));
}

static void omap2_sms_write_rot_size(u32 val, unsigned ctx)
{
        __raw_writel(val, vrfb_base + SMS_ROT_SIZE(ctx));
}

static void omap2_sms_write_rot_physical_ba(u32 val, unsigned ctx)
{
        __raw_writel(val, vrfb_base + SMS_ROT_PHYSICAL_BA(ctx));
}

static inline void restore_hw_context(int ctx)
{
        omap2_sms_write_rot_control(ctxs[ctx].control, ctx);
        omap2_sms_write_rot_size(ctxs[ctx].size, ctx);
        omap2_sms_write_rot_physical_ba(ctxs[ctx].physical_ba, ctx);
}

static u32 get_image_width_roundup(u16 width, u8 bytespp)
{
        unsigned long stride = width * bytespp;
        unsigned long ceil_pages_per_stride = (stride / VRFB_PAGE_WIDTH) +
                (stride % VRFB_PAGE_WIDTH != 0);

        return ceil_pages_per_stride * VRFB_PAGE_WIDTH / bytespp;
}

/*
 * This the extra space needed in the VRFB physical area for VRFB to safely wrap
 * any memory accesses to the invisible part of the virtual view to the physical
 * area.
 */
static inline u32 get_extra_physical_size(u16 image_width_roundup, u8 bytespp)
{
        return (OMAP_VRFB_LINE_LEN - image_width_roundup) * VRFB_PAGE_HEIGHT *
                bytespp;
}

void omap_vrfb_restore_context(void)
{
        int i;
        unsigned long map = ctx_map;

        for (i = ffs(map); i; i = ffs(map)) {
                /* i=1..32 */
                i--;
                map &= ~(1 << i);
                restore_hw_context(i);
        }
}

void omap_vrfb_adjust_size(u16 *width, u16 *height,
                u8 bytespp)
{
        *width = ALIGN(*width * bytespp, VRFB_PAGE_WIDTH) / bytespp;
        *height = ALIGN(*height, VRFB_PAGE_HEIGHT);
}
EXPORT_SYMBOL(omap_vrfb_adjust_size);

u32 omap_vrfb_min_phys_size(u16 width, u16 height, u8 bytespp)
{
        unsigned long image_width_roundup = get_image_width_roundup(width,
                bytespp);

        if (image_width_roundup > OMAP_VRFB_LINE_LEN)
                return 0;

        return (width * height * bytespp) + get_extra_physical_size(
                image_width_roundup, bytespp);
}
EXPORT_SYMBOL(omap_vrfb_min_phys_size);

u16 omap_vrfb_max_height(u32 phys_size, u16 width, u8 bytespp)
{
        unsigned long image_width_roundup = get_image_width_roundup(width,
                bytespp);
        unsigned long height;
        unsigned long extra;

        if (image_width_roundup > OMAP_VRFB_LINE_LEN)
                return 0;

        extra = get_extra_physical_size(image_width_roundup, bytespp);

        if (phys_size < extra)
                return 0;

        height = (phys_size - extra) / (width * bytespp);

        /* Virtual views provided by VRFB are limited to 2048x2048. */
        return min_t(unsigned long, height, 2048);
}
EXPORT_SYMBOL(omap_vrfb_max_height);

void omap_vrfb_setup(struct vrfb *vrfb, unsigned long paddr,
                u16 width, u16 height,
                unsigned bytespp, bool yuv_mode)
{
        unsigned pixel_size_exp;
        u16 vrfb_width;
        u16 vrfb_height;
        u8 ctx = vrfb->context;
        u32 size;
        u32 control;

        DBG("omapfb_set_vrfb(%d, %lx, %dx%d, %d, %d)\n", ctx, paddr,
                        width, height, bytespp, yuv_mode);

        /* For YUV2 and UYVY modes VRFB needs to handle pixels a bit
         * differently. See TRM. */
        if (yuv_mode) {
                bytespp *= 2;
                width /= 2;
        }

        if (bytespp == 4)
                pixel_size_exp = 2;
        else if (bytespp == 2)
                pixel_size_exp = 1;
        else {
                BUG();
                return;
        }

        vrfb_width = ALIGN(width * bytespp, VRFB_PAGE_WIDTH) / bytespp;
        vrfb_height = ALIGN(height, VRFB_PAGE_HEIGHT);

        DBG("vrfb w %u, h %u bytespp %d\n", vrfb_width, vrfb_height, bytespp);

        size  = vrfb_width << SMS_IMAGEWIDTH_OFFSET;
        size |= vrfb_height << SMS_IMAGEHEIGHT_OFFSET;

        control  = pixel_size_exp << SMS_PS_OFFSET;
        control |= VRFB_PAGE_WIDTH_EXP  << SMS_PW_OFFSET;
        control |= VRFB_PAGE_HEIGHT_EXP << SMS_PH_OFFSET;

        ctxs[ctx].physical_ba = paddr;
        ctxs[ctx].size = size;
        ctxs[ctx].control = control;

        omap2_sms_write_rot_physical_ba(paddr, ctx);
        omap2_sms_write_rot_size(size, ctx);
        omap2_sms_write_rot_control(control, ctx);

        DBG("vrfb offset pixels %d, %d\n",
                        vrfb_width - width, vrfb_height - height);

        vrfb->xres = width;
        vrfb->yres = height;
        vrfb->xoffset = vrfb_width - width;
        vrfb->yoffset = vrfb_height - height;
        vrfb->bytespp = bytespp;
        vrfb->yuv_mode = yuv_mode;
}
EXPORT_SYMBOL(omap_vrfb_setup);

int omap_vrfb_map_angle(struct vrfb *vrfb, u16 height, u8 rot)
{
        unsigned long size = height * OMAP_VRFB_LINE_LEN * vrfb->bytespp;

        vrfb->vaddr[rot] = ioremap_wc(vrfb->paddr[rot], size);

        if (!vrfb->vaddr[rot]) {
                printk(KERN_ERR "vrfb: ioremap failed\n");
                return -ENOMEM;
        }

        DBG("ioremapped vrfb area %d of size %lu into %p\n", rot, size,
                vrfb->vaddr[rot]);

        return 0;
}
EXPORT_SYMBOL(omap_vrfb_map_angle);

void omap_vrfb_release_ctx(struct vrfb *vrfb)
{
        int rot;
        int ctx = vrfb->context;

        if (ctx == 0xff)
                return;

        DBG("release ctx %d\n", ctx);

        mutex_lock(&ctx_lock);

        BUG_ON(!(ctx_map & (1 << ctx)));

        clear_bit(ctx, &ctx_map);

        for (rot = 0; rot < 4; ++rot) {
                if (vrfb->paddr[rot]) {
                        release_mem_region(vrfb->paddr[rot], OMAP_VRFB_SIZE);
                        vrfb->paddr[rot] = 0;
                }
        }

        vrfb->context = 0xff;

        mutex_unlock(&ctx_lock);
}
EXPORT_SYMBOL(omap_vrfb_release_ctx);

int omap_vrfb_request_ctx(struct vrfb *vrfb)
{
        int rot;
        u32 paddr;
        u8 ctx;
        int r;

        DBG("request ctx\n");

        mutex_lock(&ctx_lock);

        for (ctx = 0; ctx < num_ctxs; ++ctx)
                if ((ctx_map & (1 << ctx)) == 0)
                        break;

        if (ctx == num_ctxs) {
                pr_err("vrfb: no free contexts\n");
                r = -EBUSY;
                goto out;
        }

        DBG("found free ctx %d\n", ctx);

        set_bit(ctx, &ctx_map);

        memset(vrfb, 0, sizeof(*vrfb));

        vrfb->context = ctx;

        for (rot = 0; rot < 4; ++rot) {
                paddr = ctxs[ctx].base + SMS_ROT_VIRT_BASE(rot);
                if (!request_mem_region(paddr, OMAP_VRFB_SIZE, "vrfb")) {
                        pr_err("vrfb: failed to reserve VRFB "
                                        "area for ctx %d, rotation %d\n",
                                        ctx, rot * 90);
                        omap_vrfb_release_ctx(vrfb);
                        r = -ENOMEM;
                        goto out;
                }

                vrfb->paddr[rot] = paddr;

                DBG("VRFB %d/%d: %lx\n", ctx, rot*90, vrfb->paddr[rot]);
        }

        r = 0;
out:
        mutex_unlock(&ctx_lock);
        return r;
}
EXPORT_SYMBOL(omap_vrfb_request_ctx);

bool omap_vrfb_supported(void)
{
        return vrfb_loaded;
}
EXPORT_SYMBOL(omap_vrfb_supported);

static int __init vrfb_probe(struct platform_device *pdev)
{
        struct resource *mem;
        int i;

        /* first resource is the register res, the rest are vrfb contexts */
        vrfb_base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(vrfb_base))
                return PTR_ERR(vrfb_base);

        num_ctxs = pdev->num_resources - 1;

        ctxs = devm_kcalloc(&pdev->dev,
                        num_ctxs, sizeof(struct vrfb_ctx),
                        GFP_KERNEL);

        if (!ctxs)
                return -ENOMEM;

        for (i = 0; i < num_ctxs; ++i) {
                mem = platform_get_resource(pdev, IORESOURCE_MEM, 1 + i);
                if (!mem) {
                        dev_err(&pdev->dev, "can't get vrfb ctx %d address\n",
                                        i);
                        return -EINVAL;
                }

                ctxs[i].base = mem->start;
        }

        vrfb_loaded = true;

        return 0;
}

static struct platform_driver vrfb_driver = {
        .driver.name    = "omapvrfb",
};
builtin_platform_driver_probe(vrfb_driver, vrfb_probe);

MODULE_AUTHOR("Tomi Valkeinen <tomi.valkeinen@ti.com>");
MODULE_DESCRIPTION("OMAP VRFB");
MODULE_LICENSE("GPL v2");