// SPDX-License-Identifier: GPL-2.0
/*
 *  ATI Mach64 CT/VT/GT/LT Cursor Support
 */

#include <linux/fb.h>
#include <linux/init.h>
#include <linux/string.h>

#include <asm/io.h>

#ifdef __sparc__
#include <asm/fbio.h>
#endif

#include <video/mach64.h>
#include "atyfb.h"

/*
 * The hardware cursor definition requires 2 bits per pixel. The
 * Cursor size reguardless of the visible cursor size is 64 pixels
 * by 64 lines. The total memory required to define the cursor is
 * 16 bytes / line for 64 lines or 1024 bytes of data. The data
 * must be in a contigiuos format. The 2 bit cursor code values are
 * as follows:
 *
 *      00 - pixel colour = CURSOR_CLR_0
 *      01 - pixel colour = CURSOR_CLR_1
 *      10 - pixel colour = transparent (current display pixel)
 *      11 - pixel colour = 1's complement of current display pixel
 *
 *      Cursor Offset        64 pixels           Actual Displayed Area
 *            \_________________________/
 *            |                 |       |       |
 *            |<--------------->|       |       |
 *            | CURS_HORZ_OFFSET|       |       |
 *            |                 |_______|       |  64 Lines
 *            |                    ^    |       |
 *            |                    |    |       |
 *            |         CURS_VERT_OFFSET|       |
 *            |                    |    |       |
 *            |____________________|____|       |
 *
 *
 * The Screen position of the top left corner of the displayed
 * cursor is specificed by CURS_HORZ_VERT_POSN. Care must be taken
 * when the cursor hot spot is not the top left corner and the
 * physical cursor position becomes negative. It will be displayed
 * if either the horizontal or vertical cursor position is negative
 *
 * If x becomes negative the cursor manager must adjust the CURS_HORZ_OFFSET
 * to a larger number and saturate CUR_HORZ_POSN to zero.
 *
 * if Y becomes negative, CUR_VERT_OFFSET must be adjusted to a larger number,
 * CUR_OFFSET must be adjusted to a point to the appropriate line in the cursor
 * definitation and CUR_VERT_POSN must be saturated to zero.
 */

/* compose pixels based on mask */
static inline unsigned long comp(unsigned long set, unsigned long unset, unsigned long mask)
{
        return ((set ^ unset) & mask) ^ unset;
}

    /*
     *  Hardware Cursor support.
     */
static const u8 cursor_bits_lookup[16] = {
        0x00, 0x40, 0x10, 0x50, 0x04, 0x44, 0x14, 0x54,
        0x01, 0x41, 0x11, 0x51, 0x05, 0x45, 0x15, 0x55
};

static int atyfb_cursor(struct fb_info *info, struct fb_cursor *cursor)
{
        struct atyfb_par *par = (struct atyfb_par *) info->par;
        u16 xoff, yoff;
        int x, y, h;

#ifdef __sparc__
        if (par->mmaped)
                return -EPERM;
#endif
        if (par->asleep)
                return -EPERM;

        wait_for_fifo(1, par);
        if (cursor->enable)
                aty_st_le32(GEN_TEST_CNTL, aty_ld_le32(GEN_TEST_CNTL, par)
                            | HWCURSOR_ENABLE, par);
        else
                aty_st_le32(GEN_TEST_CNTL, aty_ld_le32(GEN_TEST_CNTL, par)
                                & ~HWCURSOR_ENABLE, par);

        /* set position */
        if (cursor->set & FB_CUR_SETPOS) {
                x = cursor->image.dx - cursor->hot.x - info->var.xoffset;
                if (x < 0) {
                        xoff = -x;
                        x = 0;
                } else {
                        xoff = 0;
                }

                y = cursor->image.dy - cursor->hot.y - info->var.yoffset;
                if (y < 0) {
                        yoff = -y;
                        y = 0;
                } else {
                        yoff = 0;
                }

                h = cursor->image.height;

                /*
                 * In doublescan mode, the cursor location
                 * and heigh also needs to be doubled.
                 */
                if (par->crtc.gen_cntl & CRTC_DBL_SCAN_EN) {
                        y<<=1;
                        h<<=1;
                }
                wait_for_fifo(3, par);
                aty_st_le32(CUR_OFFSET, (info->fix.smem_len >> 3) + (yoff << 1), par);
                aty_st_le32(CUR_HORZ_VERT_OFF,
                            ((u32) (64 - h + yoff) << 16) | xoff, par);
                aty_st_le32(CUR_HORZ_VERT_POSN, ((u32) y << 16) | x, par);
        }

        /* Set color map */
        if (cursor->set & FB_CUR_SETCMAP) {
                u32 fg_idx, bg_idx, fg, bg;

                fg_idx = cursor->image.fg_color;
                bg_idx = cursor->image.bg_color;

                fg = ((info->cmap.red[fg_idx] & 0xff) << 24) |
                     ((info->cmap.green[fg_idx] & 0xff) << 16) |
                     ((info->cmap.blue[fg_idx] & 0xff) << 8) | 0xff;

                bg = ((info->cmap.red[bg_idx] & 0xff) << 24) |
                     ((info->cmap.green[bg_idx] & 0xff) << 16) |
                     ((info->cmap.blue[bg_idx] & 0xff) << 8);

                wait_for_fifo(2, par);
                aty_st_le32(CUR_CLR0, bg, par);
                aty_st_le32(CUR_CLR1, fg, par);
        }

        if (cursor->set & (FB_CUR_SETSHAPE | FB_CUR_SETIMAGE)) {
            u8 *src = (u8 *)cursor->image.data;
            u8 *msk = (u8 *)cursor->mask;
            u8 __iomem *dst = (u8 __iomem *)info->sprite.addr;
            unsigned int width = (cursor->image.width + 7) >> 3;
            unsigned int height = cursor->image.height;
            unsigned int align = info->sprite.scan_align;

            unsigned int i, j, offset;
            u8 m, b;

            // Clear cursor image with 1010101010...
            fb_memset_io(dst, 0xaa, 1024);

            offset = align - width*2;

            for (i = 0; i < height; i++) {
                for (j = 0; j < width; j++) {
                        u16 l = 0xaaaa;
                        b = *src++;
                        m = *msk++;
                        switch (cursor->rop) {
                        case ROP_XOR:
                            // Upper 4 bits of mask data
                            l = cursor_bits_lookup[(b ^ m) >> 4] |
                            // Lower 4 bits of mask
                                    (cursor_bits_lookup[(b ^ m) & 0x0f] << 8);
                            break;
                        case ROP_COPY:
                            // Upper 4 bits of mask data
                            l = cursor_bits_lookup[(b & m) >> 4] |
                            // Lower 4 bits of mask
                                    (cursor_bits_lookup[(b & m) & 0x0f] << 8);
                            break;
                        }
                        /*
                         * If cursor size is not a multiple of 8 characters
                         * we must pad it with transparent pattern (0xaaaa).
                         */
                        if ((j + 1) * 8 > cursor->image.width) {
                                l = comp(l, 0xaaaa,
                                    (1 << ((cursor->image.width & 7) * 2)) - 1);
                        }
                        fb_writeb(l & 0xff, dst++);
                        fb_writeb(l >> 8, dst++);
                }
                dst += offset;
            }
        }

        return 0;
}

int aty_init_cursor(struct fb_info *info, struct fb_ops *atyfb_ops)
{
        unsigned long addr;

        info->fix.smem_len -= PAGE_SIZE;

#ifdef __sparc__
        addr = (unsigned long) info->screen_base - 0x800000 + info->fix.smem_len;
        info->sprite.addr = (u8 *) addr;
#else
#ifdef __BIG_ENDIAN
        addr = info->fix.smem_start - 0x800000 + info->fix.smem_len;
        info->sprite.addr = (u8 *) ioremap(addr, 1024);
#else
        addr = (unsigned long) info->screen_base + info->fix.smem_len;
        info->sprite.addr = (u8 *) addr;
#endif
#endif
        if (!info->sprite.addr)
                return -ENXIO;
        info->sprite.size = PAGE_SIZE;
        info->sprite.scan_align = 16;   /* Scratch pad 64 bytes wide */
        info->sprite.buf_align = 16;    /* and 64 lines tall. */
        info->sprite.flags = FB_PIXMAP_IO;

        atyfb_ops->fb_cursor = atyfb_cursor;

        return 0;
}