// SPDX-License-Identifier: GPL-2.0
/*
 * SH7760/SH7763 LCDC Framebuffer driver.
 *
 * (c) 2006-2008 MSC Vertriebsges.m.b.H.,
 *             Manuel Lauss <mano@roarinelk.homelinux.net>
 * (c) 2008 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
 *
 * PLEASE HAVE A LOOK AT Documentation/fb/sh7760fb.rst!
 *
 * Thanks to Siegfried Schaefer <s.schaefer at schaefer-edv.de>
 *     for his original source and testing!
 *
 * sh7760_setcolreg get from drivers/video/sh_mobile_lcdcfb.c
 */

#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/fb.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <asm/sh7760fb.h>

struct sh7760fb_par {
        void __iomem *base;
        int irq;

        struct sh7760fb_platdata *pd;   /* display information */

        dma_addr_t fbdma;       /* physical address */

        int rot;                /* rotation enabled? */

        u32 pseudo_palette[16];

        struct platform_device *dev;
        struct resource *ioarea;
        struct completion vsync;        /* vsync irq event */
};

static irqreturn_t sh7760fb_irq(int irq, void *data)
{
        struct completion *c = data;

        complete(c);

        return IRQ_HANDLED;
}

/* wait_for_lps - wait until power supply has reached a certain state. */
static int wait_for_lps(struct sh7760fb_par *par, int val)
{
        int i = 100;
        while (--i && ((ioread16(par->base + LDPMMR) & 3) != val))
                msleep(1);

        if (i <= 0)
                return -ETIMEDOUT;

        return 0;
}

/* en/disable the LCDC */
static int sh7760fb_blank(int blank, struct fb_info *info)
{
        struct sh7760fb_par *par = info->par;
        struct sh7760fb_platdata *pd = par->pd;
        unsigned short cntr = ioread16(par->base + LDCNTR);
        unsigned short intr = ioread16(par->base + LDINTR);
        int lps;

        if (blank == FB_BLANK_UNBLANK) {
                intr |= VINT_START;
                cntr = LDCNTR_DON2 | LDCNTR_DON;
                lps = 3;
        } else {
                intr &= ~VINT_START;
                cntr = LDCNTR_DON2;
                lps = 0;
        }

        if (pd->blank)
                pd->blank(blank);

        iowrite16(intr, par->base + LDINTR);
        iowrite16(cntr, par->base + LDCNTR);

        return wait_for_lps(par, lps);
}

static int sh7760_setcolreg (u_int regno,
        u_int red, u_int green, u_int blue,
        u_int transp, struct fb_info *info)
{
        u32 *palette = info->pseudo_palette;

        if (regno >= 16)
                return -EINVAL;

        /* only FB_VISUAL_TRUECOLOR supported */

        red >>= 16 - info->var.red.length;
        green >>= 16 - info->var.green.length;
        blue >>= 16 - info->var.blue.length;
        transp >>= 16 - info->var.transp.length;

        palette[regno] = (red << info->var.red.offset) |
                (green << info->var.green.offset) |
                (blue << info->var.blue.offset) |
                (transp << info->var.transp.offset);

        return 0;
}

static int sh7760fb_get_color_info(struct fb_info *info,
                                   u16 lddfr, int *bpp, int *gray)
{
        int lbpp, lgray;

        lgray = lbpp = 0;

        switch (lddfr & LDDFR_COLOR_MASK) {
        case LDDFR_1BPP_MONO:
                lgray = 1;
                lbpp = 1;
                break;
        case LDDFR_2BPP_MONO:
                lgray = 1;
                lbpp = 2;
                break;
        case LDDFR_4BPP_MONO:
                lgray = 1;
                fallthrough;
        case LDDFR_4BPP:
                lbpp = 4;
                break;
        case LDDFR_6BPP_MONO:
                lgray = 1;
                fallthrough;
        case LDDFR_8BPP:
                lbpp = 8;
                break;
        case LDDFR_16BPP_RGB555:
        case LDDFR_16BPP_RGB565:
                lbpp = 16;
                lgray = 0;
                break;
        default:
                fb_dbg(info, "unsupported LDDFR bit depth.\n");
                return -EINVAL;
        }

        if (bpp)
                *bpp = lbpp;
        if (gray)
                *gray = lgray;

        return 0;
}

static int sh7760fb_check_var(struct fb_var_screeninfo *var,
                              struct fb_info *info)
{
        struct fb_fix_screeninfo *fix = &info->fix;
        struct sh7760fb_par *par = info->par;
        int ret, bpp;

        /* get color info from register value */
        ret = sh7760fb_get_color_info(info, par->pd->lddfr, &bpp, NULL);
        if (ret)
                return ret;

        var->bits_per_pixel = bpp;

        if ((var->grayscale) && (var->bits_per_pixel == 1))
                fix->visual = FB_VISUAL_MONO10;
        else if (var->bits_per_pixel >= 15)
                fix->visual = FB_VISUAL_TRUECOLOR;
        else
                fix->visual = FB_VISUAL_PSEUDOCOLOR;

        /* TODO: add some more validation here */
        return 0;
}

/*
 * sh7760fb_set_par - set videomode.
 *
 * NOTE: The rotation, grayscale and DSTN codepaths are
 *     totally untested!
 */
static int sh7760fb_set_par(struct fb_info *info)
{
        struct sh7760fb_par *par = info->par;
        struct fb_videomode *vm = par->pd->def_mode;
        unsigned long sbase, dstn_off, ldsarl, stride;
        unsigned short hsynp, hsynw, htcn, hdcn;
        unsigned short vsynp, vsynw, vtln, vdln;
        unsigned short lddfr, ldmtr;
        int ret, bpp, gray;

        par->rot = par->pd->rotate;

        /* rotate only works with xres <= 320 */
        if (par->rot && (vm->xres > 320)) {
                fb_dbg(info, "rotation disabled due to display size\n");
                par->rot = 0;
        }

        /* calculate LCDC reg vals from display parameters */
        hsynp = vm->right_margin + vm->xres;
        hsynw = vm->hsync_len;
        htcn = vm->left_margin + hsynp + hsynw;
        hdcn = vm->xres;
        vsynp = vm->lower_margin + vm->yres;
        vsynw = vm->vsync_len;
        vtln = vm->upper_margin + vsynp + vsynw;
        vdln = vm->yres;

        /* get color info from register value */
        ret = sh7760fb_get_color_info(info, par->pd->lddfr, &bpp, &gray);
        if (ret)
                return ret;

        fb_dbg(info, "%dx%d %dbpp %s (orientation %s)\n", hdcn,
                vdln, bpp, gray ? "grayscale" : "color",
                par->rot ? "rotated" : "normal");

#ifdef CONFIG_CPU_LITTLE_ENDIAN
        lddfr = par->pd->lddfr | (1 << 8);
#else
        lddfr = par->pd->lddfr & ~(1 << 8);
#endif

        ldmtr = par->pd->ldmtr;

        if (!(vm->sync & FB_SYNC_HOR_HIGH_ACT))
                ldmtr |= LDMTR_CL1POL;
        if (!(vm->sync & FB_SYNC_VERT_HIGH_ACT))
                ldmtr |= LDMTR_FLMPOL;

        /* shut down LCDC before changing display parameters */
        sh7760fb_blank(FB_BLANK_POWERDOWN, info);

        iowrite16(par->pd->ldickr, par->base + LDICKR); /* pixclock */
        iowrite16(ldmtr, par->base + LDMTR);    /* polarities */
        iowrite16(lddfr, par->base + LDDFR);    /* color/depth */
        iowrite16((par->rot ? 1 << 13 : 0), par->base + LDSMR); /* rotate */
        iowrite16(par->pd->ldpmmr, par->base + LDPMMR); /* Power Management */
        iowrite16(par->pd->ldpspr, par->base + LDPSPR); /* Power Supply Ctrl */

        /* display resolution */
        iowrite16(((htcn >> 3) - 1) | (((hdcn >> 3) - 1) << 8),
                  par->base + LDHCNR);
        iowrite16(vdln - 1, par->base + LDVDLNR);
        iowrite16(vtln - 1, par->base + LDVTLNR);
        /* h/v sync signals */
        iowrite16((vsynp - 1) | ((vsynw - 1) << 12), par->base + LDVSYNR);
        iowrite16(((hsynp >> 3) - 1) | (((hsynw >> 3) - 1) << 12),
                  par->base + LDHSYNR);
        /* AC modulation sig */
        iowrite16(par->pd->ldaclnr, par->base + LDACLNR);

        stride = (par->rot) ? vtln : hdcn;
        if (!gray)
                stride *= (bpp + 7) >> 3;
        else {
                if (bpp == 1)
                        stride >>= 3;
                else if (bpp == 2)
                        stride >>= 2;
                else if (bpp == 4)
                        stride >>= 1;
                /* 6 bpp == 8 bpp */
        }

        /* if rotated, stride must be power of 2 */
        if (par->rot) {
                unsigned long bit = 1 << 31;
                while (bit) {
                        if (stride & bit)
                                break;
                        bit >>= 1;
                }
                if (stride & ~bit)
                        stride = bit << 1;      /* not P-o-2, round up */
        }
        iowrite16(stride, par->base + LDLAOR);

        /* set display mem start address */
        sbase = (unsigned long)par->fbdma;
        if (par->rot)
                sbase += (hdcn - 1) * stride;

        iowrite32(sbase, par->base + LDSARU);

        /*
         * for DSTN need to set address for lower half.
         * I (mlau) don't know which address to set it to,
         * so I guessed at (stride * yres/2).
         */
        if (((ldmtr & 0x003f) >= LDMTR_DSTN_MONO_8) &&
            ((ldmtr & 0x003f) <= LDMTR_DSTN_COLOR_16)) {

                fb_dbg(info, " ***** DSTN untested! *****\n");

                dstn_off = stride;
                if (par->rot)
                        dstn_off *= hdcn >> 1;
                else
                        dstn_off *= vdln >> 1;

                ldsarl = sbase + dstn_off;
        } else
                ldsarl = 0;

        iowrite32(ldsarl, par->base + LDSARL);  /* mem for lower half of DSTN */

        info->fix.line_length = stride;

        sh7760fb_check_var(&info->var, info);

        sh7760fb_blank(FB_BLANK_UNBLANK, info); /* panel on! */

        fb_dbg(info, "hdcn  : %6d htcn  : %6d\n", hdcn, htcn);
        fb_dbg(info, "hsynw : %6d hsynp : %6d\n", hsynw, hsynp);
        fb_dbg(info, "vdln  : %6d vtln  : %6d\n", vdln, vtln);
        fb_dbg(info, "vsynw : %6d vsynp : %6d\n", vsynw, vsynp);
        fb_dbg(info, "clksrc: %6d clkdiv: %6d\n",
                (par->pd->ldickr >> 12) & 3, par->pd->ldickr & 0x1f);
        fb_dbg(info, "ldpmmr: 0x%04x ldpspr: 0x%04x\n", par->pd->ldpmmr,
                par->pd->ldpspr);
        fb_dbg(info, "ldmtr : 0x%04x lddfr : 0x%04x\n", ldmtr, lddfr);
        fb_dbg(info, "ldlaor: %ld\n", stride);
        fb_dbg(info, "ldsaru: 0x%08lx ldsarl: 0x%08lx\n", sbase, ldsarl);

        return 0;
}

static const struct fb_ops sh7760fb_ops = {
        .owner = THIS_MODULE,
        FB_DEFAULT_IOMEM_OPS,
        .fb_blank = sh7760fb_blank,
        .fb_check_var = sh7760fb_check_var,
        .fb_setcolreg = sh7760_setcolreg,
        .fb_set_par = sh7760fb_set_par,
};

static void sh7760fb_free_mem(struct fb_info *info)
{
        struct sh7760fb_par *par = info->par;

        if (!info->screen_base)
                return;

        dma_free_coherent(info->device, info->screen_size,
                          info->screen_base, par->fbdma);

        par->fbdma = 0;
        info->screen_base = NULL;
        info->screen_size = 0;
}

/* allocate the framebuffer memory. This memory must be in Area3,
 * (dictated by the DMA engine) and contiguous, at a 512 byte boundary.
 */
static int sh7760fb_alloc_mem(struct fb_info *info)
{
        struct sh7760fb_par *par = info->par;
        void *fbmem;
        unsigned long vram;
        int ret, bpp;

        if (info->screen_base)
                return 0;

        /* get color info from register value */
        ret = sh7760fb_get_color_info(info, par->pd->lddfr, &bpp, NULL);
        if (ret) {
                printk(KERN_ERR "colinfo\n");
                return ret;
        }

        /* min VRAM: xres_min = 16, yres_min = 1, bpp = 1: 2byte -> 1 page
           max VRAM: xres_max = 1024, yres_max = 1024, bpp = 16: 2MB */

        vram = info->var.xres * info->var.yres;
        if (info->var.grayscale) {
                if (bpp == 1)
                        vram >>= 3;
                else if (bpp == 2)
                        vram >>= 2;
                else if (bpp == 4)
                        vram >>= 1;
        } else if (bpp > 8)
                vram *= 2;
        if ((vram < 1) || (vram > 1024 * 2048)) {
                fb_dbg(info, "too much VRAM required. Check settings\n");
                return -ENODEV;
        }

        if (vram < PAGE_SIZE)
                vram = PAGE_SIZE;

        fbmem = dma_alloc_coherent(info->device, vram, &par->fbdma, GFP_KERNEL);
        if (!fbmem)
                return -ENOMEM;

        if ((par->fbdma & SH7760FB_DMA_MASK) != SH7760FB_DMA_MASK) {
                dma_free_coherent(info->device, vram, fbmem, par->fbdma);
                dev_err(info->device, "kernel gave me memory at 0x%08lx, which is"
                        "unusable for the LCDC\n", (unsigned long)par->fbdma);
                return -ENOMEM;
        }

        info->screen_base = fbmem;
        info->screen_size = vram;
        info->fix.smem_start = (unsigned long)info->screen_base;
        info->fix.smem_len = info->screen_size;

        return 0;
}

static int sh7760fb_probe(struct platform_device *pdev)
{
        struct fb_info *info;
        struct resource *res;
        struct sh7760fb_par *par;
        int ret;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (unlikely(res == NULL)) {
                dev_err(&pdev->dev, "invalid resource\n");
                return -EINVAL;
        }

        info = framebuffer_alloc(sizeof(struct sh7760fb_par), &pdev->dev);
        if (!info)
                return -ENOMEM;

        par = info->par;
        par->dev = pdev;

        par->pd = pdev->dev.platform_data;
        if (!par->pd) {
                dev_dbg(&pdev->dev, "no display setup data!\n");
                ret = -ENODEV;
                goto out_fb;
        }

        par->ioarea = request_mem_region(res->start,
                                         resource_size(res), pdev->name);
        if (!par->ioarea) {
                dev_err(&pdev->dev, "mmio area busy\n");
                ret = -EBUSY;
                goto out_fb;
        }

        par->base = ioremap(res->start, resource_size(res));
        if (!par->base) {
                dev_err(&pdev->dev, "cannot remap\n");
                ret = -ENODEV;
                goto out_res;
        }

        iowrite16(0, par->base + LDINTR);       /* disable vsync irq */
        par->irq = platform_get_irq(pdev, 0);
        if (par->irq >= 0) {
                ret = request_irq(par->irq, sh7760fb_irq, 0,
                                  "sh7760-lcdc", &par->vsync);
                if (ret) {
                        dev_err(&pdev->dev, "cannot grab IRQ\n");
                        par->irq = -ENXIO;
                } else
                        disable_irq_nosync(par->irq);
        }

        fb_videomode_to_var(&info->var, par->pd->def_mode);

        ret = sh7760fb_alloc_mem(info);
        if (ret) {
                dev_dbg(info->device, "framebuffer memory allocation failed!\n");
                goto out_unmap;
        }

        info->pseudo_palette = par->pseudo_palette;

        /* fixup color register bitpositions. These are fixed by hardware */
        info->var.red.offset = 11;
        info->var.red.length = 5;
        info->var.red.msb_right = 0;

        info->var.green.offset = 5;
        info->var.green.length = 6;
        info->var.green.msb_right = 0;

        info->var.blue.offset = 0;
        info->var.blue.length = 5;
        info->var.blue.msb_right = 0;

        info->var.transp.offset = 0;
        info->var.transp.length = 0;
        info->var.transp.msb_right = 0;

        strcpy(info->fix.id, "sh7760-lcdc");

        /* set the DON2 bit now, before cmap allocation, as it will randomize
         * palette memory.
         */
        iowrite16(LDCNTR_DON2, par->base + LDCNTR);
        info->fbops = &sh7760fb_ops;

        ret = fb_alloc_cmap(&info->cmap, 256, 0);
        if (ret) {
                dev_dbg(&pdev->dev, "Unable to allocate cmap memory\n");
                goto out_mem;
        }

        ret = register_framebuffer(info);
        if (ret < 0) {
                dev_dbg(&pdev->dev, "cannot register fb!\n");
                goto out_cmap;
        }
        platform_set_drvdata(pdev, info);

        printk(KERN_INFO "%s: memory at phys 0x%08lx-0x%08lx, size %ld KiB\n",
               pdev->name,
               (unsigned long)par->fbdma,
               (unsigned long)(par->fbdma + info->screen_size - 1),
               info->screen_size >> 10);

        return 0;

out_cmap:
        sh7760fb_blank(FB_BLANK_POWERDOWN, info);
        fb_dealloc_cmap(&info->cmap);
out_mem:
        sh7760fb_free_mem(info);
out_unmap:
        if (par->irq >= 0)
                free_irq(par->irq, &par->vsync);
        iounmap(par->base);
out_res:
        release_mem_region(res->start, resource_size(res));
out_fb:
        framebuffer_release(info);
        return ret;
}

static void sh7760fb_remove(struct platform_device *dev)
{
        struct fb_info *info = platform_get_drvdata(dev);
        struct sh7760fb_par *par = info->par;

        sh7760fb_blank(FB_BLANK_POWERDOWN, info);
        unregister_framebuffer(info);
        fb_dealloc_cmap(&info->cmap);
        sh7760fb_free_mem(info);
        if (par->irq >= 0)
                free_irq(par->irq, &par->vsync);
        iounmap(par->base);
        release_mem_region(par->ioarea->start, resource_size(par->ioarea));
        framebuffer_release(info);
}

static struct platform_driver sh7760_lcdc_driver = {
        .driver = {
                   .name = "sh7760-lcdc",
                   },
        .probe = sh7760fb_probe,
        .remove = sh7760fb_remove,
};

module_platform_driver(sh7760_lcdc_driver);

MODULE_AUTHOR("Nobuhiro Iwamatsu, Manuel Lauss");
MODULE_DESCRIPTION("FBdev for SH7760/63 integrated LCD Controller");
MODULE_LICENSE("GPL v2");