path: root/arch/powerpc/kernel/btext.c

/*
 * 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/init.h>
#include <linux/export.h>
#include <linux/memblock.h>

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

#define NO_SCROLL

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

static void draw_byte(unsigned char c, long locX, long locY);
static void draw_byte_32(unsigned char *bits, unsigned int *base, int rb);
static void draw_byte_16(unsigned char *bits, unsigned int *base, int rb);
static void draw_byte_8(unsigned char *bits, unsigned int *base, int rb);

#define __force_data __attribute__((__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};

#define cmapsz	(16*256)

static unsigned char vga_font[cmapsz];

int boot_text_mapped __force_data = 0;
int force_printk_to_btext = 0;

#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 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;
	}
	if (PVR_VER(mfspr(SPRN_PVR)) != 1) {
		/* 603, 604, G3, G4, ... */
		lowbits = addr & ~0xFF000000UL;
		addr &= 0xFF000000UL;
		disp_BAT[0] = vaddr | (BL_16M<<2) | 2;
		disp_BAT[1] = addr | (_PAGE_NO_CACHE | _PAGE_GUARDED | BPP_RW);	
	} else {
		/* 601 */
		lowbits = addr & ~0xFF800000UL;
		addr &= 0xFF800000UL;
		disp_BAT[0] = vaddr | (_PAGE_NO_CACHE | PP_RWXX) | 4;
		disp_BAT[1] = addr | BL_8M | 0x40;
	}
	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.
 */

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

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

int btext_initialize(struct