Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
/*
 *  linux/drivers/video/offb.c -- Open Firmware based frame buffer device
 *
 *	Copyright (C) 1997 Geert Uytterhoeven
 *
 *  This driver is partly based on the PowerMac console driver:
 *
 *	Copyright (C) 1996 Paul Mackerras
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License. See the file COPYING in the main directory of this archive for
 *  more details.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/interrupt.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/pci.h>
#include <asm/io.h>

#ifdef CONFIG_PPC64
#include <asm/pci-bridge.h>
#endif

#ifdef CONFIG_PPC32
#include <asm/bootx.h>
#endif

#include "macmodes.h"

/* Supported palette hacks */
enum {
	cmap_unknown,
	cmap_simple,		/* ATI Mach64 */
	cmap_r128,		/* ATI Rage128 */
	cmap_M3A,		/* ATI Rage Mobility M3 Head A */
	cmap_M3B,		/* ATI Rage Mobility M3 Head B */
	cmap_radeon,		/* ATI Radeon */
	cmap_gxt2000,		/* IBM GXT2000 */
	cmap_avivo,		/* ATI R5xx */
	cmap_qemu,		/* qemu vga */
};

struct offb_par {
	volatile void __iomem *cmap_adr;
	volatile void __iomem *cmap_data;
	int cmap_type;
	int blanked;
};

struct offb_par default_par;

#ifdef CONFIG_PPC32
extern boot_infos_t *boot_infos;
#endif

/* Definitions used by the Avivo palette hack */
#define AVIVO_DC_LUT_RW_SELECT                  0x6480
#define AVIVO_DC_LUT_RW_MODE                    0x6484
#define AVIVO_DC_LUT_RW_INDEX                   0x6488
#define AVIVO_DC_LUT_SEQ_COLOR                  0x648c
#define AVIVO_DC_LUT_PWL_DATA                   0x6490
#define AVIVO_DC_LUT_30_COLOR                   0x6494
#define AVIVO_DC_LUT_READ_PIPE_SELECT           0x6498
#define AVIVO_DC_LUT_WRITE_EN_MASK              0x649c
#define AVIVO_DC_LUT_AUTOFILL                   0x64a0

#define AVIVO_DC_LUTA_CONTROL                   0x64c0
#define AVIVO_DC_LUTA_BLACK_OFFSET_BLUE         0x64c4
#define AVIVO_DC_LUTA_BLACK_OFFSET_GREEN        0x64c8
#define AVIVO_DC_LUTA_BLACK_OFFSET_RED          0x64cc
#define AVIVO_DC_LUTA_WHITE_OFFSET_BLUE         0x64d0
#define AVIVO_DC_LUTA_WHITE_OFFSET_GREEN        0x64d4
#define AVIVO_DC_LUTA_WHITE_OFFSET_RED          0x64d8

#define AVIVO_DC_LUTB_CONTROL                   0x6cc0
#define AVIVO_DC_LUTB_BLACK_OFFSET_BLUE         0x6cc4
#define AVIVO_DC_LUTB_BLACK_OFFSET_GREEN        0x6cc8
#define AVIVO_DC_LUTB_BLACK_OFFSET_RED          0x6ccc
#define AVIVO_DC_LUTB_WHITE_OFFSET_BLUE         0x6cd0
#define AVIVO_DC_LUTB_WHITE_OFFSET_GREEN        0x6cd4
#define AVIVO_DC_LUTB_WHITE_OFFSET_RED          0x6cd8

    /*
     *  Set a single color register. The values supplied are already
     *  rounded down to the hardware's capabilities (according to the
     *  entries in the var structure). Return != 0 for invalid regno.
     */

static int offb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
			  u_int transp, struct fb_info *info)
{
	struct offb_par *par = (struct offb_par *) info->par;

	if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
		u32 *pal = info->pseudo_palette;
		u32 cr = red >> (16 - info->var.red.length);
		u32 cg = green >> (16 - info->var.green.length);
		u32 cb = blue >> (16 - info->var.blue.length);
		u32 value;

		if (regno >= 16)
			return -EINVAL;

		value = (cr << info->var.red.offset) |
			(cg << info->var.green.offset) |
			(cb << info->var.blue.offset);
		if (info->var.transp.length > 0) {
			u32 mask = (1 << info->var.transp.length) - 1;
			mask <<= info->var.transp.offset;
			value |= mask;
		}
		pal[regno] = value;
		return 0;
	}

	if (regno > 255)
		return -EINVAL;

	red >>= 8;
	green >>= 8;
	blue >>= 8;

	if (!par->cmap_adr)
		return 0;

	switch (par->cmap_type) {
	case cmap_simple:
		writeb(regno, par->cmap_adr);
		writeb(red, par->cmap_data);
		writeb(green, par->cmap_data);
		writeb(blue, par->cmap_data);
		break;
	case cmap_M3A:
		/* Clear PALETTE_ACCESS_CNTL in DAC_CNTL */
		out_le32(par->cmap_adr + 0x58,
			 in_le32(par->cmap_adr + 0x58) & ~0x20);
	case cmap_r128:
		/* Set palette index & data */
		out_8(par->cmap_adr + 0xb0, regno);
		out_le32(par->cmap_adr + 0xb4,
			 (red << 16 | green << 8 | blue));
		break;
	case cmap_M3B:
		/* Set PALETTE_ACCESS_CNTL in DAC_CNTL */
		out_le32(par->cmap_adr + 0x58,
			 in_le32(par->cmap_adr + 0x58) | 0x20);
		/* Set palette index & data */
		out_8(par->cmap_adr + 0xb0, regno);
		out_le32(par->cmap_adr + 0xb4, (red << 16 | green << 8 | blue));
		break;
	case cmap_radeon:
		/* Set palette index & data (could be smarter) */
		out_8(par->cmap_adr + 0xb0, regno);
		out_le32(par->cmap_adr + 0xb4, (red << 16 | green << 8 | blue));
		break;
	case cmap_gxt2000:
		out_le32(((unsigned __iomem *) par->cmap_adr) + regno,
			 (red << 16 | green << 8 | blue));
		break;
	case cmap_avivo:
		/* Write to both LUTs for now */
		writel(1, par->cmap_adr + AVIVO_DC_LUT_RW_SELECT);
		writeb(regno, par->cmap_adr + AVIVO_DC_LUT_RW_INDEX);
		writel(((red) << 22) | ((green) << 12) | ((blue) << 2),
		       par->cmap_adr + AVIVO_DC_LUT_30_COLOR);
		writel(0, par->cmap_adr + AVIVO_DC_LUT_RW_SELECT);
		writeb(regno, par->cmap_adr + AVIVO_DC_LUT_RW_INDEX);
		writel(((red) << 22) | ((green) << 12) | ((blue) << 2),
		       par->cmap_adr + AVIVO_DC_LUT_30_COLOR);
		break;
	}

	return 0;
}

    /*
     *  Blank the display.
     */

static int offb_blank(int blank, struct fb_info *info)
{
	struct offb_par *par = (struct offb_par *) info->par;
	int i, j;

	if (!par->cmap_adr)
		return 0;

	if (!par->blanked)
		if (!blank)
			return 0;

	par->blanked = blank;

	if (blank)
		for (i = 0; i < 256; i++) {
			switch (par->cmap_type) {
			case cmap_simple:
				writeb(i, par->cmap_adr);
				for (j = 0; j < 3; j++)
					writeb(0, par->cmap_data);
				break;
			case cmap_M3A:
				/* Clear PALETTE_ACCESS_CNTL in DAC_CNTL */
				out_le32(par->cmap_adr + 0x58,
					 in_le32(par->cmap_adr + 0x58) & ~0x20);
			case cmap_r128:
				/* Set palette index & data */
				out_8(par->cmap_adr + 0xb0, i);
				out_le32(par->cmap_adr + 0xb4, 0);
				break;
			case cmap_M3B:
				/* Set PALETTE_ACCESS_CNTL in DAC_CNTL */
				out_le32(par->cmap_adr + 0x58,
					 in_le32(par->cmap_adr + 0x58) | 0x20);
				/* Set palette index & data */
				out_8(par->cmap_adr + 0xb0, i);
				out_le32(par->cmap_adr + 0xb4, 0);
				break;
			case cmap_radeon:
				out_8(par->cmap_adr + 0xb0, i);
				out_le32(par->cmap_adr + 0xb4, 0);
				break;
			case cmap_gxt2000:
				out_le32(((unsigned __iomem *) par->cmap_adr) + i,
					 0);
				break;
			case cmap_avivo:
				writel(1, par->cmap_adr + AVIVO_DC_LUT_RW_SELECT);
				writeb(i, par->cmap_adr + AVIVO_DC_LUT_RW_INDEX);
				writel(0, par->cmap_adr + AVIVO_DC_LUT_30_COLOR);
				writel(0, par->cmap_adr + AVIVO_DC_LUT_RW_SELECT);
				writeb(i, par->cmap_adr + AVIVO_DC_LUT_RW_INDEX);
				writel(0, par->cmap_adr + AVIVO_DC_LUT_30_COLOR);
				break;
			}
	} else
		fb_set_cmap(&info->cmap, info);
	return 0;
}

static int offb_set_par(struct fb_info *info)
{
	struct offb_par *par = (struct offb_par *) info->par;

	/* On avivo, initialize palette control */
	if (par->cmap_type == cmap_avivo) {
		writel(0, par->cmap_adr + AVIVO_DC_LUTA_CONTROL);
		writel(0, par->cmap_adr + AVIVO_DC_LUTA_BLACK_OFFSET_BLUE);
		writel(0, par->cmap_adr + AVIVO_DC_LUTA_BLACK_OFFSET_GREEN);
		writel(0, par->cmap_adr + AVIVO_DC_LUTA_BLACK_OFFSET_RED);
		writel(0x0000ffff, par->cmap_adr + AVIVO_DC_LUTA_WHITE_OFFSET_BLUE);
		writel(0x0000ffff, par->cmap_adr + AVIVO_DC_LUTA_WHITE_OFFSET_GREEN);
		writel(0x0000ffff, par->cmap_adr + AVIVO_DC_LUTA_WHITE_OFFSET_RED);
		writel(0, par->cmap_adr + AVIVO_DC_LUTB_CONTROL);
		writel(0, par->cmap_adr + AVIVO_DC_LUTB_BLACK_OFFSET_BLUE);
		writel(0, par->cmap_adr + AVIVO_DC_LUTB_BLACK_OFFSET_GREEN);
		writel(0, par->cmap_adr + AVIVO_DC_LUTB_BLACK_OFFSET_RED);
		writel(0x0000ffff, par->cmap_adr + AVIVO_DC_LUTB_WHITE_OFFSET_BLUE);
		writel(0x0000ffff, par->cmap_adr + AVIVO_DC_LUTB_WHITE_OFFSET_GREEN);
		writel(0x0000ffff, par->cmap_adr + AVIVO_DC_LUTB_WHITE_OFFSET_RED);
		writel(1, par->cmap_adr + AVIVO_DC_LUT_RW_SELECT);
		writel(0, par->cmap_adr + AVIVO_DC_LUT_RW_MODE);
		writel(0x0000003f, par->cmap_adr + AVIVO_DC_LUT_WRITE_EN_MASK);
		writel(0, par->cmap_adr + AVIVO_DC_LUT_RW_SELECT);
		writel(0, par->cmap_adr + AVIVO_DC_LUT_RW_MODE);
		writel(0x0000003f, par->cmap_adr + AVIVO_DC_LUT_WRITE_EN_MASK);
	}
	return 0;
}

static void offb_destroy(struct fb_info *info)
{
	if (info->screen_base)
		iounmap(info->screen_base);
	release_mem_region(info->apertures->ranges[0].base, info->apertures->ranges[0].size);
	framebuffer_release(info);
}

static struct fb_ops offb_ops = {
	.owner		= THIS_MODULE,
	.fb_destroy	= offb_destroy,
	.fb_setcolreg	= offb_setcolreg,
	.fb_set_par	= offb_set_par,
	.fb_blank	= offb_blank,
	.fb_fillrect	= cfb_fillrect,
	.fb_copyarea	= cfb_copyarea,
	.fb_imageblit	= cfb_imageblit,
};

static void __iomem *offb_map_reg(struct device_node *np, int index,
				  unsigned long offset, unsigned long size)
{
	const u32 *addrp;
	u64 asize, taddr;
	unsigned int flags;

	addrp = of_get_pci_address(np, index, &asize, &flags);
	if (addrp == NULL)
		addrp = of_get_address(np, index, &asize, &flags);
	if (addrp == NULL)
		return NULL;
	if ((flags & (IORESOURCE_IO | IORESOURCE_MEM)) == 0)
		return NULL;
	if ((offset + size) > asize)
		return NULL;
	taddr = of_translate_address(np, addrp);
	if (taddr == OF_BAD_ADDR)
		return NULL;
	return ioremap(taddr + offset, size);
}

static void offb_init_palette_hacks(struct fb_info *info, struct device_node *dp,
				    const char *name, unsigned long address)
{
	struct offb_par *par = (struct offb_par *) info->par;

	if (dp && !strncmp(name, "ATY,Rage128", 11)) {
		par->cmap_adr = offb_map_reg(dp, 2, 0, 0x1fff);
		if (par->cmap_adr)
			par->cmap_type = cmap_r128;
	} else if (dp && (!strncmp(name, "ATY,RageM3pA", 12)
			  || !strncmp(name, "ATY,RageM3p12A", 14))) {
		par->cmap_adr = offb_map_reg(dp, 2, 0, 0x1fff);
		if (par->cmap_adr)
			par->cmap_type = cmap_M3A;
	} else if (dp && !strncmp(name, "ATY,RageM3pB", 12)) {
		par->cmap_adr = offb_map_reg(dp, 2, 0, 0x1fff);
		if (par->cmap_adr)
			par->cmap_type = cmap_M3B;
	} else if (dp && !strncmp(name, "ATY,Rage6", 9)) {
		par->cmap_adr = offb_map_reg(dp, 1, 0, 0x1fff);
		if (par->cmap_adr)
			par->cmap_type = cmap_radeon;
	} else if (!strncmp(name, "ATY,", 4)) {
		unsigned long base = address & 0xff000000UL;
		par->cmap_adr =
			ioremap(base + 0x7ff000, 0x1000) + 0xcc0;
		par->cmap_data = par->cmap_adr + 1;
		par->cmap_type = cmap_simple;
	} else if (dp && (of_device_is_compatible(dp, "pci1014,b7") ||
			  of_device_is_compatible(dp, "pci1014,21c"))) {
		par->cmap_adr = offb_map_reg(dp, 0, 0x6000, 0x1000);
		if (par->cmap_adr)
			par->cmap_type = cmap_gxt2000;
	} else if (dp && !strncmp(name, "vga,Display-", 12)) {
		/* Look for AVIVO initialized by SLOF */
		struct device_node *pciparent = of_get_parent(dp);
		const u32 *vid, *did;
		vid = of_get_property(pciparent, "vendor-id", NULL);
		did = of_get_property(pciparent, "device-id", NULL);
		/* This will match most R5xx */
		if (vid && did && *vid == 0x1002 &&
		    ((*did >= 0x7100 && *did < 0x7800) ||
		     (*did >= 0x9400))) {
			par->cmap_adr = offb_map_reg(pciparent, 2, 0, 0x10000);
			if (par->cmap_adr)
				par->cmap_type = cmap_avivo;
		}
		of_node_put(pciparent);
	} else if (dp && of_device_is_compatible(dp, "qemu,std-vga")) {
		const u32 io_of_addr[3] = { 0x01000000, 0x0, 0x0 };
		u64 io_addr = of_translate_address(dp, io_of_addr);
		if (io_addr != OF_BAD_ADDR) {
			par->cmap_adr = ioremap(io_addr + 0x3c8, 2);
			if (par->cmap_adr) {
				par->cmap_type = cmap_simple;
				par->cmap_data = par->cmap_adr + 1;
			}
		}
	}
	info->fix.visual = (par->cmap_type != cmap_unknown) ?
		FB_VISUAL_PSEUDOCOLOR : FB_VISUAL_STATIC_PSEUDOCOLOR;
}

static void __init offb_init_fb(const char *name, const char *full_name,
				int width, int height, int depth,
				int pitch, unsigned long address,
				int foreign_endian, struct device_node *dp)
{
	unsigned long res_size = pitch * height;
	struct offb_par *par = &default_par;
	unsigned long res_start = address;
	struct fb_fix_screeninfo *fix;
	struct fb_var_screeninfo *var;
	struct fb_info *info;

	if (!request_mem_region(res_start, res_size, "offb"))
		return;

	printk(KERN_INFO
	       "Using unsupported %dx%d %s at %lx, depth=%d, pitch=%d\n",
	       width, height, name, address, depth, pitch);
	if (depth != 8 && depth != 15 && depth != 16 && depth != 32) {
		printk(KERN_ERR "%s: can't use depth = %d\n", full_name,
		       depth);
		release_mem_region(res_start, res_size);
		return;
	}

	info = framebuffer_alloc(sizeof(u32) * 16, NULL);
	
	if (info == 0) {
		release_mem_region(res_start, res_size);
		return;
	}

	fix = &info->fix;
	var = &info->var;
	info->par = par;

	strcpy(fix->id, "OFfb ");
	strncat(fix->id, name, sizeof(fix->id) - sizeof("OFfb "));
	fix->id[sizeof(fix->id) - 1] = '\0';

	var->xres = var->xres_virtual = width;
	var->yres = var->yres_virtual = height;
	fix->line_length = pitch;

	fix->smem_start = address;
	fix->smem_len = pitch * height;
	fix->type = FB_TYPE_PACKED_PIXELS;
	fix->type_aux = 0;

	par->cmap_type = cmap_unknown;
	if (depth == 8)
		offb_init_palette_hacks(info, dp, name, address);
	else
		fix->visual = FB_VISUAL_TRUECOLOR;

	var->xoffset = var->yoffset = 0;
	switch (depth) {
	case 8:
		var->bits_per_pixel = 8;
		var->red.offset = 0;
		var->red.length = 8;
		var->green.offset = 0;
		var->green.length = 8;
		var->blue.offset = 0;
		var->blue.length = 8;
		var->transp.offset = 0;
		var->transp.length = 0;
		break;
	case 15:		/* RGB 555 */
		var->bits_per_pixel = 16;
		var->red.offset = 10;
		var->red.length = 5;
		var->green.offset = 5;
		var->green.length = 5;
		var->blue.offset = 0;
		var->blue.length = 5;
		var->transp.offset = 0;
		var->transp.length = 0;
		break;
	case 16:		/* RGB 565 */
		var->bits_per_pixel = 16;
		var->red.offset = 11;
		var->red.length = 5;
		var->green.offset = 5;
		var->green.length = 6;
		var->blue.offset = 0;
		var->blue.length = 5;
		var->transp.offset = 0;
		var->transp.length = 0;
		break;
	case 32:		/* RGB 888 */
		var->bits_per_pixel = 32;
		var->red.offset = 16;
		var->red.length = 8;
		var->green.offset = 8;
		var->green.length = 8;
		var->blue.offset = 0;
		var->blue.length = 8;
		var->transp.offset = 24;
		var->transp.length = 8;
		break;
	}
	var->red.msb_right = var->green.msb_right = var->blue.msb_right =
	    var->transp.msb_right = 0;
	var->grayscale = 0;
	var->nonstd = 0;
	var->activate = 0;
	var->height = var->width = -1;
	var->pixclock = 10000;
	var->left_margin = var->right_margin = 16;
	var->upper_margin = var->lower_margin = 16;
	var->hsync_len = var->vsync_len = 8;
	var->sync = 0;
	var->vmode = FB_VMODE_NONINTERLACED;

	/* set offb aperture size for generic probing */
	info->apertures = alloc_apertures(1);
	if (!info->apertures)
		goto out_aper;
	info->apertures->ranges[0].base = address;
	info->apertures->ranges[0].size = fix->smem_len;

	info->fbops = &offb_ops;
	info->screen_base = ioremap(address, fix->smem_len);
	info->pseudo_palette = (void *) (info + 1);
	info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE | foreign_endian;

	fb_alloc_cmap(&info->cmap, 256, 0);

	if (register_framebuffer(info) < 0)
		goto out_err;

	printk(KERN_INFO "fb%d: Open Firmware frame buffer device on %s\n",
	       info->node, full_name);
	return;

out_err:
	iounmap(info->screen_base);
out_aper:
	iounmap(par->cmap_adr);
	par->cmap_adr = NULL;
	framebuffer_release(info);
	release_mem_region(res_start, res_size);
}


static void __init offb_init_nodriver(struct device_node *dp, int no_real_node)
{
	unsigned int len;
	int i, width = 640, height = 480, depth = 8, pitch = 640;
	unsigned int flags, rsize, addr_prop = 0;
	unsigned long max_size = 0;
	u64 rstart, address = OF_BAD_ADDR;
	const u32 *pp, *addrp, *up;
	u64 asize;
	int foreign_endian = 0;

#ifdef __BIG_ENDIAN
	if (of_get_property(dp, "little-endian", NULL))
		foreign_endian = FBINFO_FOREIGN_ENDIAN;
#else
	if (of_get_property(dp, "big-endian", NULL))
		foreign_endian = FBINFO_FOREIGN_ENDIAN;
#endif

	pp = of_get_property(dp, "linux,bootx-depth", &len);
	if (pp == NULL)
		pp = of_get_property(dp, "depth", &len);
	if (pp && len == sizeof(u32))
		depth = *pp;

	pp = of_get_property(dp, "linux,bootx-width", &len);
	if (pp == NULL)
		pp = of_get_property(dp, "width", &len);
	if (pp && len == sizeof(u32))
		width = *pp;

	pp = of_get_property(dp, "linux,bootx-height", &len);
	if (pp == NULL)
		pp = of_get_property(dp, "height", &len);
	if (pp && len == sizeof(u32))
		height = *pp;

	pp = of_get_property(dp, "linux,bootx-linebytes", &len);
	if (pp == NULL)
		pp = of_get_property(dp, "linebytes", &len);
	if (pp && len == sizeof(u32) && (*pp != 0xffffffffu))
		pitch = *pp;
	else
		pitch = width * ((depth + 7) / 8);

	rsize = (unsigned long)pitch * (unsigned long)height;

	/* Ok, now we try to figure out the address of the framebuffer.
	 *
	 * Unfortunately, Open Firmware doesn't provide a standard way to do
	 * so. All we can do is a dodgy heuristic that happens to work in
	 * practice. On most machines, the "address" property contains what
	 * we need, though not on Matrox cards found in IBM machines. What I've
	 * found that appears to give good results is to go through the PCI
	 * ranges and pick one that is both big enough and if possible encloses
	 * the "address" property. If none match, we pick the biggest
	 */
	up = of_get_property(dp, "linux,bootx-addr", &len);
	if (up == NULL)
		up = of_get_property(dp, "address", &len);
	if (up && len == sizeof(u32))
		addr_prop = *up;

	/* Hack for when BootX is passing us */
	if (no_real_node)
		goto skip_addr;

	for (i = 0; (addrp = of_get_address(dp, i, &asize, &flags))
		     != NULL; i++) {
		int match_addrp = 0;

		if (!(flags & IORESOURCE_MEM))
			continue;
		if (asize < rsize)
			continue;
		rstart = of_translate_address(dp, addrp);
		if (rstart == OF_BAD_ADDR)
			continue;
		if (addr_prop && (rstart <= addr_prop) &&
		    ((rstart + asize) >= (addr_prop + rsize)))
			match_addrp = 1;
		if (match_addrp) {
			address = addr_prop;
			break;
		}
		if (rsize > max_size) {
			max_size = rsize;
			address = OF_BAD_ADDR;
 		}

		if (address == OF_BAD_ADDR)
			address = rstart;
	}
 skip_addr:
	if (address == OF_BAD_ADDR && addr_prop)
		address = (u64)addr_prop;
	if (address != OF_BAD_ADDR) {
		/* kludge for valkyrie */
		if (strcmp(dp->name, "valkyrie") == 0)
			address += 0x1000;
		offb_init_fb(no_real_node ? "bootx" : dp->name,
			     no_real_node ? "display" : dp->full_name,
			     width, height, depth, pitch, address,
			     foreign_endian, no_real_node ? NULL : dp);
	}
}

static int __init offb_init(void)
{
	struct device_node *dp = NULL, *boot_disp = NULL;

	if (fb_get_options("offb", NULL))
		return -ENODEV;

	/* Check if we have a MacOS display without a node spec */
	if (of_get_property(of_chosen, "linux,bootx-noscreen", NULL) != NULL) {
		/* The old code tried to work out which node was the MacOS
		 * display based on the address. I'm dropping that since the
		 * lack of a node spec only happens with old BootX versions
		 * (users can update) and with this code, they'll still get
		 * a display (just not the palette hacks).
		 */
		offb_init_nodriver(of_chosen, 1);
	}

	for (dp = NULL; (dp = of_find_node_by_type(dp, "display"));) {
		if (of_get_property(dp, "linux,opened", NULL) &&
		    of_get_property(dp, "linux,boot-display", NULL)) {
			boot_disp = dp;
			offb_init_nodriver(dp, 0);
		}
	}
	for (dp = NULL; (dp = of_find_node_by_type(dp, "display"));) {
		if (of_get_property(dp, "linux,opened", NULL) &&
		    dp != boot_disp)
			offb_init_nodriver(dp, 0);
	}

	return 0;
}


module_init(offb_init);
MODULE_LICENSE("GPL");