// SPDX-License-Identifier: GPL-2.0
/*
 * Procedures for drawing on the screen early on in the boot process.
 *
 * Benjamin Herrenschmidt <benh@kernel.crashing.org>
 */
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/hex.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/font.h>
#include <linux/memblock.h>
#include <linux/pgtable.h>
#include <linux/of.h>

#include <asm/sections.h>
#include <asm/btext.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/udbg.h>
#include <asm/setup.h>

#define NO_SCROLL

#ifndef NO_SCROLL
static void scrollscreen(void);
#endif

#define __force_data __section(".data")

static int g_loc_X __force_data;
static int g_loc_Y __force_data;
static int g_max_loc_X __force_data;
static int g_max_loc_Y __force_data;

static int dispDeviceRowBytes __force_data;
static int dispDeviceDepth  __force_data;
static int dispDeviceRect[4] __force_data;
static unsigned char *dispDeviceBase __force_data;
static unsigned char *logicalDisplayBase __force_data;

unsigned long disp_BAT[2] __initdata = {0, 0};

static int boot_text_mapped __force_data;

extern void rmci_on(void);
extern void rmci_off(void);

static inline void rmci_maybe_on(void)
{
#if defined(CONFIG_PPC_EARLY_DEBUG_BOOTX) && defined(CONFIG_PPC64)
        if (!(mfmsr() & MSR_DR))
                rmci_on();
#endif
}

static inline void rmci_maybe_off(void)
{
#if defined(CONFIG_PPC_EARLY_DEBUG_BOOTX) && defined(CONFIG_PPC64)
        if (!(mfmsr() & MSR_DR))
                rmci_off();
#endif
}


#ifdef CONFIG_PPC32
/* Calc BAT values for mapping the display and store them
 * in disp_BAT.  Those values are then used from head.S to map
 * the display during identify_machine() and MMU_Init()
 *
 * The display is mapped to virtual address 0xD0000000, rather
 * than 1:1, because some CHRP machines put the frame buffer
 * in the region starting at 0xC0000000 (PAGE_OFFSET).
 * This mapping is temporary and will disappear as soon as the
 * setup done by MMU_Init() is applied.
 *
 * For now, we align the BAT and then map 8Mb on 601 and 16Mb
 * on other PPCs. This may cause trouble if the framebuffer
 * is really badly aligned, but I didn't encounter this case
 * yet.
 */
void __init btext_prepare_BAT(void)
{
        unsigned long vaddr = PAGE_OFFSET + 0x10000000;
        unsigned long addr;
        unsigned long lowbits;

        addr = (unsigned long)dispDeviceBase;
        if (!addr) {
                boot_text_mapped = 0;
                return;
        }
        lowbits = addr & ~0xFF000000UL;
        addr &= 0xFF000000UL;
        disp_BAT[0] = vaddr | (BL_16M<<2) | 2;
        disp_BAT[1] = addr | (_PAGE_NO_CACHE | _PAGE_GUARDED | BPP_RW);
        logicalDisplayBase = (void *) (vaddr + lowbits);
}
#endif


/* This function can be used to enable the early boot text when doing
 * OF booting or within bootx init. It must be followed by a btext_unmap()
 * call before the logical address becomes unusable
 */
void __init btext_setup_display(int width, int height, int depth, int pitch,
                                unsigned long address)
{
        g_loc_X = 0;
        g_loc_Y = 0;
        g_max_loc_X = width / 8;
        g_max_loc_Y = height / 16;
        logicalDisplayBase = (unsigned char *)address;
        dispDeviceBase = (unsigned char *)address;
        dispDeviceRowBytes = pitch;
        dispDeviceDepth = depth == 15 ? 16 : depth;
        dispDeviceRect[0] = dispDeviceRect[1] = 0;
        dispDeviceRect[2] = width;
        dispDeviceRect[3] = height;
        boot_text_mapped = 1;
}

void __init btext_unmap(void)
{
        boot_text_mapped = 0;
}

/* Here's a small text engine to use during early boot
 * or for debugging purposes
 *
 * todo:
 *
 *  - build some kind of vgacon with it to enable early printk
 *  - move to a separate file
 *  - add a few video driver hooks to keep in sync with display
 *    changes.
 */

void btext_map(void)
{
        unsigned long base, offset, size;
        unsigned char *vbase;

        /* By default, we are no longer mapped */
        boot_text_mapped = 0;
        if (!dispDeviceBase)
                return;
        base = ((unsigned long) dispDeviceBase) & 0xFFFFF000UL;
        offset = ((unsigned long) dispDeviceBase) - base;
        size = dispDeviceRowBytes * dispDeviceRect[3] + offset
                + dispDeviceRect[0];
        vbase = ioremap_wc(base, size);
        if (!vbase)
                return;
        logicalDisplayBase = vbase + offset;
        boot_text_mapped = 1;
}

static int __init btext_initialize(struct device_node *np)
{
        unsigned int width, height, depth, pitch;
        unsigned long address = 0;
        const u32 *prop;

        prop = of_get_property(np, "linux,bootx-width", NULL);
        if (prop == NULL)
                prop = of_get_property(np, "width", NULL);
        if (prop == NULL)
                return -EINVAL;
        width = *prop;
        prop = of_get_property(np, "linux,bootx-height", NULL);
        if (prop == NULL)
                prop = of_get_property(np, "height", NULL);
        if (prop == NULL)
                return -EINVAL;
        height = *prop;
        prop = of_get_property(np, "linux,bootx-depth", NULL);
        if (prop == NULL)
                prop = of_get_property(np, "depth", NULL);
        if (prop == NULL)
                return -EINVAL;
        depth = *prop;
        pitch = width * ((depth + 7) / 8);
        prop = of_get_property(np, "linux,bootx-linebytes", NULL);
        if (prop == NULL)
                prop = of_get_property(np, "linebytes", NULL);
        if (prop && *prop != 0xffffffffu)
                pitch = *prop;
        if (pitch == 1)
                pitch = 0x1000;
        prop = of_get_property(np, "linux,bootx-addr", NULL);
        if (prop == NULL)
                prop = of_get_property(np, "address", NULL);
        if (prop)
                address = *prop;

        /* FIXME: Add support for PCI reg properties. Right now, only
         * reliable on macs
         */
        if (address == 0)
                return -EINVAL;

        g_loc_X = 0;
        g_loc_Y = 0;
        g_max_loc_X = width / 8;
        g_max_loc_Y = height / 16;
        dispDeviceBase = (unsigned char *)address;
        dispDeviceRowBytes = pitch;
        dispDeviceDepth = depth == 15 ? 16 : depth;
        dispDeviceRect[0] = dispDeviceRect[1] = 0;
        dispDeviceRect[2] = width;
        dispDeviceRect[3] = height;

        btext_map();

        return 0;
}

int __init btext_find_display(int allow_nonstdout)
{
        struct device_node *np = of_stdout;
        int rc = -ENODEV;

        if (!of_node_is_type(np, "display")) {
                printk("boot stdout isn't a display !\n");
                np = NULL;
        }
        if (np)
                rc = btext_initialize(np);
        if (rc == 0 || !allow_nonstdout)
                return rc;

        for_each_node_by_type(np, "display") {
                if (of_property_read_bool(np, "linux,opened")) {
                        printk("trying %pOF ...\n", np);
                        rc = btext_initialize(np);
                        printk("result: %d\n", rc);
                }
                if (rc == 0) {
                        of_node_put(np);
                        break;
                }
        }
        return rc;
}

/* Calc the base address of a given point (x,y) */
static unsigned char * calc_base(int x, int y)
{
        unsigned char *base;

        base = logicalDisplayBase;
        if (!base)
                base = dispDeviceBase;
        base += (x + dispDeviceRect[0]) * (dispDeviceDepth >> 3);
        base += (y + dispDeviceRect[1]) * dispDeviceRowBytes;
        return base;
}

/* Adjust the display to a new resolution */
void btext_update_display(unsigned long phys, int width, int height,
                          int depth, int pitch)
{
        if (!dispDeviceBase)
                return;

        /* check it's the same frame buffer (within 256MB) */
        if ((phys ^ (unsigned long)dispDeviceBase) & 0xf0000000)
                return;

        dispDeviceBase = (__u8 *) phys;
        dispDeviceRect[0] = 0;
        dispDeviceRect[1] = 0;
        dispDeviceRect[2] = width;
        dispDeviceRect[3] = height;
        dispDeviceDepth = depth;
        dispDeviceRowBytes = pitch;
        if (boot_text_mapped) {
                iounmap(logicalDisplayBase);
                boot_text_mapped = 0;
        }
        btext_map();
        g_loc_X = 0;
        g_loc_Y = 0;
        g_max_loc_X = width / 8;
        g_max_loc_Y = height / 16;
}
EXPORT_SYMBOL(btext_update_display);

void __init btext_clearscreen(void)
{
        unsigned int *base      = (unsigned int *)calc_base(0, 0);
        unsigned long width     = ((dispDeviceRect[2] - dispDeviceRect[0]) *
                                        (dispDeviceDepth >> 3)) >> 2;
        int i,j;

        rmci_maybe_on();
        for (i=0; i<(dispDeviceRect[3] - dispDeviceRect[1]); i++)
        {
                unsigned int *ptr = base;
                for(j=width; j; --j)
                        *(ptr++) = 0;
                base += (dispDeviceRowBytes >> 2);
        }
        rmci_maybe_off();
}

void __init btext_flushscreen(void)
{
        unsigned int *base      = (unsigned int *)calc_base(0, 0);
        unsigned long width     = ((dispDeviceRect[2] - dispDeviceRect[0]) *
                                        (dispDeviceDepth >> 3)) >> 2;
        int i,j;

        for (i=0; i < (dispDeviceRect[3] - dispDeviceRect[1]); i++)
        {
                unsigned int *ptr = base;
                for(j = width; j > 0; j -= 8) {
                        __asm__ __volatile__ ("dcbst 0,%0" :: "r" (ptr));
                        ptr += 8;
                }
                base += (dispDeviceRowBytes >> 2);
        }
        __asm__ __volatile__ ("sync" ::: "memory");
}

void __init btext_flushline(void)
{
        unsigned int *base      = (unsigned int *)calc_base(0, g_loc_Y << 4);
        unsigned long width     = ((dispDeviceRect[2] - dispDeviceRect[0]) *
                                        (dispDeviceDepth >> 3)) >> 2;
        int i,j;

        for (i=0; i < 16; i++)
        {
                unsigned int *ptr = base;
                for(j = width; j > 0; j -= 8) {
                        __asm__ __volatile__ ("dcbst 0,%0" :: "r" (ptr));
                        ptr += 8;
                }
                base += (dispDeviceRowBytes >> 2);
        }
        __asm__ __volatile__ ("sync" ::: "memory");
}


#ifndef NO_SCROLL
static void scrollscreen(void)
{
        unsigned int *src       = (unsigned int *)calc_base(0,16);
        unsigned int *dst       = (unsigned int *)calc_base(0,0);
        unsigned long width     = ((dispDeviceRect[2] - dispDeviceRect[0]) *
                                   (dispDeviceDepth >> 3)) >> 2;
        int i,j;

        rmci_maybe_on();

        for (i=0; i<(dispDeviceRect[3] - dispDeviceRect[1] - 16); i++)
        {
                unsigned int *src_ptr = src;
                unsigned int *dst_ptr = dst;
                for(j=width; j; --j)
                        *(dst_ptr++) = *(src_ptr++);
                src += (dispDeviceRowBytes >> 2);
                dst += (dispDeviceRowBytes >> 2);
        }
        for (i=0; i<16; i++)
        {
                unsigned int *dst_ptr = dst;
                for(j=width; j; --j)
                        *(dst_ptr++) = 0;
                dst += (dispDeviceRowBytes >> 2);
        }

        rmci_maybe_off();
}
#endif /* ndef NO_SCROLL */

static unsigned int expand_bits_8[16] = {
        0x00000000,
        0x000000ff,
        0x0000ff00,
        0x0000ffff,
        0x00ff0000,
        0x00ff00ff,
        0x00ffff00,
        0x00ffffff,
        0xff000000,
        0xff0000ff,
        0xff00ff00,
        0xff00ffff,
        0xffff0000,
        0xffff00ff,
        0xffffff00,
        0xffffffff
};

static unsigned int expand_bits_16[4] = {
        0x00000000,
        0x0000ffff,
        0xffff0000,
        0xffffffff
};


static void draw_byte_32(const unsigned char *font, unsigned int *base, int rb)
{
        int l, bits;
        int fg = 0xFFFFFFFFUL;
        int bg = 0x00000000UL;

        for (l = 0; l < 16; ++l)
        {
                bits = *font++;
                base[0] = (-(bits >> 7) & fg) ^ bg;
                base[1] = (-((bits >> 6) & 1) & fg) ^ bg;
                base[2] = (-((bits >> 5) & 1) & fg) ^ bg;
                base[3] = (-((bits >> 4) & 1) & fg) ^ bg;
                base[4] = (-((bits >> 3) & 1) & fg) ^ bg;
                base[5] = (-((bits >> 2) & 1) & fg) ^ bg;
                base[6] = (-((bits >> 1) & 1) & fg) ^ bg;
                base[7] = (-(bits & 1) & fg) ^ bg;
                base = (unsigned int *) ((char *)base + rb);
        }
}

static inline void draw_byte_16(const unsigned char *font, unsigned int *base, int rb)
{
        int l, bits;
        int fg = 0xFFFFFFFFUL;
        int bg = 0x00000000UL;
        unsigned int *eb = (int *)expand_bits_16;

        for (l = 0; l < 16; ++l)
        {
                bits = *font++;
                base[0] = (eb[bits >> 6] & fg) ^ bg;
                base[1] = (eb[(bits >> 4) & 3] & fg) ^ bg;
                base[2] = (eb[(bits >> 2) & 3] & fg) ^ bg;
                base[3] = (eb[bits & 3] & fg) ^ bg;
                base = (unsigned int *) ((char *)base + rb);
        }
}

static inline void draw_byte_8(const unsigned char *font, unsigned int *base, int rb)
{
        int l, bits;
        int fg = 0x0F0F0F0FUL;
        int bg = 0x00000000UL;
        unsigned int *eb = (int *)expand_bits_8;

        for (l = 0; l < 16; ++l)
        {
                bits = *font++;
                base[0] = (eb[bits >> 4] & fg) ^ bg;
                base[1] = (eb[bits & 0xf] & fg) ^ bg;
                base = (unsigned int *) ((char *)base + rb);
        }
}

static noinline void draw_byte(unsigned char c, long locX, long locY)
{
        unsigned char *base     = calc_base(locX << 3, locY << 4);
        unsigned int font_index = c * 16;
        const unsigned char *font = PTRRELOC(font_sun_8x16.data) + font_index;
        int rb                  = dispDeviceRowBytes;

        rmci_maybe_on();
        switch(dispDeviceDepth) {
        case 24:
        case 32:
                draw_byte_32(font, (unsigned int *)base, rb);
                break;
        case 15:
        case 16:
                draw_byte_16(font, (unsigned int *)base, rb);
                break;
        case 8:
                draw_byte_8(font, (unsigned int *)base, rb);
                break;
        }
        rmci_maybe_off();
}

void btext_drawchar(char c)
{
        int cline = 0;
#ifdef NO_SCROLL
        int x;
#endif
        if (!boot_text_mapped)
                return;

        switch (c) {
        case '\b':
                if (g_loc_X > 0)
                        --g_loc_X;
                break;
        case '\t':
                g_loc_X = (g_loc_X & -8) + 8;
                break;
        case '\r':
                g_loc_X = 0;
                break;
        case '\n':
                g_loc_X = 0;
                g_loc_Y++;
                cline = 1;
                break;
        default:
                draw_byte(c, g_loc_X++, g_loc_Y);
        }
        if (g_loc_X >= g_max_loc_X) {
                g_loc_X = 0;
                g_loc_Y++;
                cline = 1;
        }
#ifndef NO_SCROLL
        while (g_loc_Y >= g_max_loc_Y) {
                scrollscreen();
                g_loc_Y--;
        }
#else
        /* wrap around from bottom to top of screen so we don't
           waste time scrolling each line.  -- paulus. */
        if (g_loc_Y >= g_max_loc_Y)
                g_loc_Y = 0;
        if (cline) {
                for (x = 0; x < g_max_loc_X; ++x)
                        draw_byte(' ', x, g_loc_Y);
        }
#endif
}

void btext_drawstring(const char *c)
{
        if (!boot_text_mapped)
                return;
        while (*c)
                btext_drawchar(*c++);
}

void __init btext_drawtext(const char *c, unsigned int len)
{
        if (!boot_text_mapped)
                return;
        while (len--)
                btext_drawchar(*c++);
}

void __init btext_drawhex(unsigned long v)
{
        if (!boot_text_mapped)
                return;
#ifdef CONFIG_PPC64
        btext_drawchar(hex_asc_hi(v >> 56));
        btext_drawchar(hex_asc_lo(v >> 56));
        btext_drawchar(hex_asc_hi(v >> 48));
        btext_drawchar(hex_asc_lo(v >> 48));
        btext_drawchar(hex_asc_hi(v >> 40));
        btext_drawchar(hex_asc_lo(v >> 40));
        btext_drawchar(hex_asc_hi(v >> 32));
        btext_drawchar(hex_asc_lo(v >> 32));
#endif
        btext_drawchar(hex_asc_hi(v >> 24));
        btext_drawchar(hex_asc_lo(v >> 24));
        btext_drawchar(hex_asc_hi(v >> 16));
        btext_drawchar(hex_asc_lo(v >> 16));
        btext_drawchar(hex_asc_hi(v >> 8));
        btext_drawchar(hex_asc_lo(v >> 8));
        btext_drawchar(hex_asc_hi(v));
        btext_drawchar(hex_asc_lo(v));
        btext_drawchar(' ');
}

void __init udbg_init_btext(void)
{
        /* If btext is enabled, we might have a BAT setup for early display,
         * thus we do enable some very basic udbg output
         */
        udbg_putc = btext_drawchar;
}