// SPDX-License-Identifier: GPL-2.0

#include <linux/fb.h>
#include <linux/linux_logo.h>

#include "fb_internal.h"

bool fb_center_logo __read_mostly;
int fb_logo_count __read_mostly = -1;

static inline unsigned int safe_shift(unsigned int d, int n)
{
        return n < 0 ? d >> -n : d << n;
}

static void fb_set_logocmap(struct fb_info *info,
                                   const struct linux_logo *logo)
{
        struct fb_cmap palette_cmap;
        u16 palette_green[16];
        u16 palette_blue[16];
        u16 palette_red[16];
        int i, j, n;
        const unsigned char *clut = logo->clut;

        palette_cmap.start = 0;
        palette_cmap.len = 16;
        palette_cmap.red = palette_red;
        palette_cmap.green = palette_green;
        palette_cmap.blue = palette_blue;
        palette_cmap.transp = NULL;

        for (i = 0; i < logo->clutsize; i += n) {
                n = logo->clutsize - i;
                /* palette_cmap provides space for only 16 colors at once */
                if (n > 16)
                        n = 16;
                palette_cmap.start = 32 + i;
                palette_cmap.len = n;
                for (j = 0; j < n; ++j) {
                        palette_cmap.red[j] = clut[0] << 8 | clut[0];
                        palette_cmap.green[j] = clut[1] << 8 | clut[1];
                        palette_cmap.blue[j] = clut[2] << 8 | clut[2];
                        clut += 3;
                }
                fb_set_cmap(&palette_cmap, info);
        }
}

static void  fb_set_logo_truepalette(struct fb_info *info,
                                            const struct linux_logo *logo,
                                            u32 *palette)
{
        static const unsigned char mask[] = {
                0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff
        };
        unsigned char redmask, greenmask, bluemask;
        int redshift, greenshift, blueshift;
        int i;
        const unsigned char *clut = logo->clut;

        /*
         * We have to create a temporary palette since console palette is only
         * 16 colors long.
         */
        /* Bug: Doesn't obey msb_right ... (who needs that?) */
        redmask   = mask[info->var.red.length   < 8 ? info->var.red.length   : 8];
        greenmask = mask[info->var.green.length < 8 ? info->var.green.length : 8];
        bluemask  = mask[info->var.blue.length  < 8 ? info->var.blue.length  : 8];
        redshift   = info->var.red.offset   - (8 - info->var.red.length);
        greenshift = info->var.green.offset - (8 - info->var.green.length);
        blueshift  = info->var.blue.offset  - (8 - info->var.blue.length);

        for (i = 0; i < logo->clutsize; i++) {
                palette[i+32] = (safe_shift((clut[0] & redmask), redshift) |
                                 safe_shift((clut[1] & greenmask), greenshift) |
                                 safe_shift((clut[2] & bluemask), blueshift));
                clut += 3;
        }
}

static void fb_set_logo_directpalette(struct fb_info *info,
                                             const struct linux_logo *logo,
                                             u32 *palette)
{
        int redshift, greenshift, blueshift;
        int i;

        redshift = info->var.red.offset;
        greenshift = info->var.green.offset;
        blueshift = info->var.blue.offset;

        for (i = 32; i < 32 + logo->clutsize; i++)
                palette[i] = i << redshift | i << greenshift | i << blueshift;
}

static void fb_set_logo(struct fb_info *info,
                               const struct linux_logo *logo, u8 *dst,
                               int depth)
{
        int i, j, k;
        const u8 *src = logo->data;
        u8 xor = (info->fix.visual == FB_VISUAL_MONO01) ? 0xff : 0;
        u8 fg = 1, d;

        switch (fb_get_color_depth(&info->var, &info->fix)) {
        case 1:
                fg = 1;
                break;
        case 2:
                fg = 3;
                break;
        default:
                fg = 7;
                break;
        }

        if (info->fix.visual == FB_VISUAL_MONO01 ||
            info->fix.visual == FB_VISUAL_MONO10)
                fg = ~((u8) (0xfff << info->var.green.length));

        switch (depth) {
        case 4:
                for (i = 0; i < logo->height; i++)
                        for (j = 0; j < logo->width; src++) {
                                *dst++ = *src >> 4;
                                j++;
                                if (j < logo->width) {
                                        *dst++ = *src & 0x0f;
                                        j++;
                                }
                        }
                break;
        case 1:
                for (i = 0; i < logo->height; i++) {
                        for (j = 0; j < logo->width; src++) {
                                d = *src ^ xor;
                                for (k = 7; k >= 0 && j < logo->width; k--) {
                                        *dst++ = ((d >> k) & 1) ? fg : 0;
                                        j++;
                                }
                        }
                }
                break;
        }
}

/*
 * Three (3) kinds of logo maps exist.  linux_logo_clut224 (>16 colors),
 * linux_logo_vga16 (16 colors) and linux_logo_mono (2 colors).  Depending on
 * the visual format and color depth of the framebuffer, the DAC, the
 * pseudo_palette, and the logo data will be adjusted accordingly.
 *
 * Case 1 - linux_logo_clut224:
 * Color exceeds the number of console colors (16), thus we set the hardware DAC
 * using fb_set_cmap() appropriately.  The "needs_cmapreset"  flag will be set.
 *
 * For visuals that require color info from the pseudo_palette, we also construct
 * one for temporary use. The "needs_directpalette" or "needs_truepalette" flags
 * will be set.
 *
 * Case 2 - linux_logo_vga16:
 * The number of colors just matches the console colors, thus there is no need
 * to set the DAC or the pseudo_palette.  However, the bitmap is packed, ie,
 * each byte contains color information for two pixels (upper and lower nibble).
 * To be consistent with fb_imageblit() usage, we therefore separate the two
 * nibbles into separate bytes. The "depth" flag will be set to 4.
 *
 * Case 3 - linux_logo_mono:
 * This is similar with Case 2.  Each byte contains information for 8 pixels.
 * We isolate each bit and expand each into a byte. The "depth" flag will
 * be set to 1.
 */
static struct logo_data {
        int depth;
        int needs_directpalette;
        int needs_truepalette;
        int needs_cmapreset;
        const struct linux_logo *logo;
} fb_logo __read_mostly;

static void fb_rotate_logo_ud(const u8 *in, u8 *out, u32 width, u32 height)
{
        u32 size = width * height, i;

        out += size - 1;

        for (i = size; i--; )
                *out-- = *in++;
}

static void fb_rotate_logo_cw(const u8 *in, u8 *out, u32 width, u32 height)
{
        int i, j, h = height - 1;

        for (i = 0; i < height; i++)
                for (j = 0; j < width; j++)
                        out[height * j + h - i] = *in++;
}

static void fb_rotate_logo_ccw(const u8 *in, u8 *out, u32 width, u32 height)
{
        int i, j, w = width - 1;

        for (i = 0; i < height; i++)
                for (j = 0; j < width; j++)
                        out[height * (w - j) + i] = *in++;
}

static void fb_rotate_logo(struct fb_info *info, u8 *dst,
                           struct fb_image *image, int rotate)
{
        u32 tmp;

        if (rotate == FB_ROTATE_UD) {
                fb_rotate_logo_ud(image->data, dst, image->width,
                                  image->height);
                image->dx = info->var.xres - image->width - image->dx;
                image->dy = info->var.yres - image->height - image->dy;
        } else if (rotate == FB_ROTATE_CW) {
                fb_rotate_logo_cw(image->data, dst, image->width,
                                  image->height);
                swap(image->width, image->height);
                tmp = image->dy;
                image->dy = image->dx;
                image->dx = info->var.xres - image->width - tmp;
        } else if (rotate == FB_ROTATE_CCW) {
                fb_rotate_logo_ccw(image->data, dst, image->width,
                                   image->height);
                swap(image->width, image->height);
                tmp = image->dx;
                image->dx = image->dy;
                image->dy = info->var.yres - image->height - tmp;
        }

        image->data = dst;
}

static void fb_do_show_logo(struct fb_info *info, struct fb_image *image,
                            int rotate, unsigned int num)
{
        unsigned int x;

        if (image->width > info->var.xres || image->height > info->var.yres)
                return;

        if (rotate == FB_ROTATE_UR) {
                for (x = 0;
                     x < num && image->dx + image->width <= info->var.xres;
                     x++) {
                        info->fbops->fb_imageblit(info, image);
                        image->dx += image->width + 8;
                }
        } else if (rotate == FB_ROTATE_UD) {
                u32 dx = image->dx;

                for (x = 0; x < num && image->dx <= dx; x++) {
                        info->fbops->fb_imageblit(info, image);
                        image->dx -= image->width + 8;
                }
        } else if (rotate == FB_ROTATE_CW) {
                for (x = 0;
                     x < num && image->dy + image->height <= info->var.yres;
                     x++) {
                        info->fbops->fb_imageblit(info, image);
                        image->dy += image->height + 8;
                }
        } else if (rotate == FB_ROTATE_CCW) {
                u32 dy = image->dy;

                for (x = 0; x < num && image->dy <= dy; x++) {
                        info->fbops->fb_imageblit(info, image);
                        image->dy -= image->height + 8;
                }
        }
}

static int fb_show_logo_line(struct fb_info *info, int rotate,
                             const struct linux_logo *logo, int y,
                             unsigned int n)
{
        u32 *palette = NULL, *saved_pseudo_palette = NULL;
        unsigned char *logo_new = NULL, *logo_rotate = NULL;
        struct fb_image image;

        /* Return if the frame buffer is not mapped or suspended */
        if (logo == NULL || info->state != FBINFO_STATE_RUNNING ||
            info->fbops->owner)
                return 0;

        image.depth = 8;
        image.data = logo->data;

        if (fb_logo.needs_cmapreset)
                fb_set_logocmap(info, logo);

        if (fb_logo.needs_truepalette ||
            fb_logo.needs_directpalette) {
                palette = kmalloc(256 * 4, GFP_KERNEL);
                if (palette == NULL)
                        return 0;

                if (fb_logo.needs_truepalette)
                        fb_set_logo_truepalette(info, logo, palette);
                else
                        fb_set_logo_directpalette(info, logo, palette);

                saved_pseudo_palette = info->pseudo_palette;
                info->pseudo_palette = palette;
        }

        if (fb_logo.depth <= 4) {
                logo_new = kmalloc_array(logo->width, logo->height,
                                         GFP_KERNEL);
                if (logo_new == NULL) {
                        kfree(palette);
                        if (saved_pseudo_palette)
                                info->pseudo_palette = saved_pseudo_palette;
                        return 0;
                }
                image.data = logo_new;
                fb_set_logo(info, logo, logo_new, fb_logo.depth);
        }

        if (fb_center_logo) {
                int xres = info->var.xres;
                int yres = info->var.yres;

                if (rotate == FB_ROTATE_CW || rotate == FB_ROTATE_CCW) {
                        xres = info->var.yres;
                        yres = info->var.xres;
                }

                while (n && (n * (logo->width + 8) - 8 > xres))
                        --n;
                image.dx = (xres - (n * (logo->width + 8) - 8)) / 2;
                image.dy = y ?: (yres - logo->height) / 2;
        } else {
                image.dx = 0;
                image.dy = y;
        }

        image.width = logo->width;
        image.height = logo->height;

        if (rotate) {
                logo_rotate = kmalloc_array(logo->width, logo->height,
                                            GFP_KERNEL);
                if (logo_rotate)
                        fb_rotate_logo(info, logo_rotate, &image, rotate);
        }

        fb_do_show_logo(info, &image, rotate, n);

        kfree(palette);
        if (saved_pseudo_palette != NULL)
                info->pseudo_palette = saved_pseudo_palette;
        kfree(logo_new);
        kfree(logo_rotate);
        return image.dy + logo->height;
}

#ifdef CONFIG_FB_LOGO_EXTRA

#define FB_LOGO_EX_NUM_MAX 10
static struct logo_data_extra {
        const struct linux_logo *logo;
        unsigned int n;
} fb_logo_ex[FB_LOGO_EX_NUM_MAX];
static unsigned int fb_logo_ex_num;

void fb_append_extra_logo(const struct linux_logo *logo, unsigned int n)
{
        if (!n || fb_logo_ex_num == FB_LOGO_EX_NUM_MAX)
                return;

        fb_logo_ex[fb_logo_ex_num].logo = logo;
        fb_logo_ex[fb_logo_ex_num].n = n;
        fb_logo_ex_num++;
}

static int fb_prepare_extra_logos(struct fb_info *info, unsigned int height,
                                  unsigned int yres)
{
        unsigned int i;

        /* FIXME: logo_ex supports only truecolor fb. */
        if (info->fix.visual != FB_VISUAL_TRUECOLOR)
                fb_logo_ex_num = 0;

        for (i = 0; i < fb_logo_ex_num; i++) {
                if (fb_logo_ex[i].logo->type != fb_logo.logo->type) {
                        fb_logo_ex[i].logo = NULL;
                        continue;
                }
                height += fb_logo_ex[i].logo->height;
                if (height > yres) {
                        height -= fb_logo_ex[i].logo->height;
                        fb_logo_ex_num = i;
                        break;
                }
        }
        return height;
}

static int fb_show_extra_logos(struct fb_info *info, int y, int rotate)
{
        unsigned int i;

        for (i = 0; i < fb_logo_ex_num; i++)
                y = fb_show_logo_line(info, rotate,
                                      fb_logo_ex[i].logo, y, fb_logo_ex[i].n);

        return y;
}
#endif /* CONFIG_FB_LOGO_EXTRA */

int fb_prepare_logo(struct fb_info *info, int rotate)
{
        int depth = fb_get_color_depth(&info->var, &info->fix);
        unsigned int yres;
        int height;

        memset(&fb_logo, 0, sizeof(struct logo_data));

        if (info->flags & FBINFO_MISC_TILEBLITTING ||
            info->fbops->owner || !fb_logo_count)
                return 0;

        if (info->fix.visual == FB_VISUAL_DIRECTCOLOR) {
                depth = info->var.blue.length;
                if (info->var.red.length < depth)
                        depth = info->var.red.length;
                if (info->var.green.length < depth)
                        depth = info->var.green.length;
        }

        if (info->fix.visual == FB_VISUAL_STATIC_PSEUDOCOLOR && depth > 4) {
                /* assume console colormap */
                depth = 4;
        }

        /* Return if no suitable logo was found */
        fb_logo.logo = fb_find_logo(depth);

        if (!fb_logo.logo)
                return 0;

        if (rotate == FB_ROTATE_UR || rotate == FB_ROTATE_UD)
                yres = info->var.yres;
        else
                yres = info->var.xres;

        if (fb_logo.logo->height > yres) {
                fb_logo.logo = NULL;
                return 0;
        }

        /* What depth we asked for might be different from what we get */
        if (fb_logo.logo->type == LINUX_LOGO_CLUT224)
                fb_logo.depth = 8;
        else if (fb_logo.logo->type == LINUX_LOGO_VGA16)
                fb_logo.depth = 4;
        else
                fb_logo.depth = 1;


        if (fb_logo.depth > 4 && depth > 4) {
                switch (info->fix.visual) {
                case FB_VISUAL_TRUECOLOR:
                        fb_logo.needs_truepalette = 1;
                        break;
                case FB_VISUAL_DIRECTCOLOR:
                        fb_logo.needs_directpalette = 1;
                        fb_logo.needs_cmapreset = 1;
                        break;
                case FB_VISUAL_PSEUDOCOLOR:
                        fb_logo.needs_cmapreset = 1;
                        break;
                }
        }

        height = fb_logo.logo->height;
        if (fb_center_logo)
                height += (yres - fb_logo.logo->height) / 2;
#ifdef CONFIG_FB_LOGO_EXTRA
        height = fb_prepare_extra_logos(info, height, yres);
#endif

        return height;
}

int fb_show_logo(struct fb_info *info, int rotate)
{
        unsigned int count;
        int y;

        if (!fb_logo_count)
                return 0;

        count = fb_logo_count < 0 ? num_online_cpus() : fb_logo_count;
        y = fb_show_logo_line(info, rotate, fb_logo.logo, 0, count);
#ifdef CONFIG_FB_LOGO_EXTRA
        y = fb_show_extra_logos(info, y, rotate);
#endif

        return y;
}