xref: /linux/drivers/gpu/drm/tiny/ofdrm.c (revision fbf46565c67c626849c7ce2a326972d3008d2a91)
1 // SPDX-License-Identifier: GPL-2.0-only
2 
3 #include <linux/of_address.h>
4 #include <linux/pci.h>
5 #include <linux/platform_device.h>
6 
7 #include <drm/drm_aperture.h>
8 #include <drm/drm_atomic.h>
9 #include <drm/drm_atomic_state_helper.h>
10 #include <drm/drm_connector.h>
11 #include <drm/drm_damage_helper.h>
12 #include <drm/drm_device.h>
13 #include <drm/drm_drv.h>
14 #include <drm/drm_fbdev_generic.h>
15 #include <drm/drm_format_helper.h>
16 #include <drm/drm_framebuffer.h>
17 #include <drm/drm_gem_atomic_helper.h>
18 #include <drm/drm_gem_framebuffer_helper.h>
19 #include <drm/drm_gem_shmem_helper.h>
20 #include <drm/drm_managed.h>
21 #include <drm/drm_modeset_helper_vtables.h>
22 #include <drm/drm_plane_helper.h>
23 #include <drm/drm_probe_helper.h>
24 #include <drm/drm_simple_kms_helper.h>
25 
26 #define DRIVER_NAME	"ofdrm"
27 #define DRIVER_DESC	"DRM driver for OF platform devices"
28 #define DRIVER_DATE	"20220501"
29 #define DRIVER_MAJOR	1
30 #define DRIVER_MINOR	0
31 
32 #define PCI_VENDOR_ID_ATI_R520	0x7100
33 #define PCI_VENDOR_ID_ATI_R600	0x9400
34 
35 #define OFDRM_GAMMA_LUT_SIZE	256
36 
37 /* Definitions used by the Avivo palette  */
38 #define AVIVO_DC_LUT_RW_SELECT                  0x6480
39 #define AVIVO_DC_LUT_RW_MODE                    0x6484
40 #define AVIVO_DC_LUT_RW_INDEX                   0x6488
41 #define AVIVO_DC_LUT_SEQ_COLOR                  0x648c
42 #define AVIVO_DC_LUT_PWL_DATA                   0x6490
43 #define AVIVO_DC_LUT_30_COLOR                   0x6494
44 #define AVIVO_DC_LUT_READ_PIPE_SELECT           0x6498
45 #define AVIVO_DC_LUT_WRITE_EN_MASK              0x649c
46 #define AVIVO_DC_LUT_AUTOFILL                   0x64a0
47 #define AVIVO_DC_LUTA_CONTROL                   0x64c0
48 #define AVIVO_DC_LUTA_BLACK_OFFSET_BLUE         0x64c4
49 #define AVIVO_DC_LUTA_BLACK_OFFSET_GREEN        0x64c8
50 #define AVIVO_DC_LUTA_BLACK_OFFSET_RED          0x64cc
51 #define AVIVO_DC_LUTA_WHITE_OFFSET_BLUE         0x64d0
52 #define AVIVO_DC_LUTA_WHITE_OFFSET_GREEN        0x64d4
53 #define AVIVO_DC_LUTA_WHITE_OFFSET_RED          0x64d8
54 #define AVIVO_DC_LUTB_CONTROL                   0x6cc0
55 #define AVIVO_DC_LUTB_BLACK_OFFSET_BLUE         0x6cc4
56 #define AVIVO_DC_LUTB_BLACK_OFFSET_GREEN        0x6cc8
57 #define AVIVO_DC_LUTB_BLACK_OFFSET_RED          0x6ccc
58 #define AVIVO_DC_LUTB_WHITE_OFFSET_BLUE         0x6cd0
59 #define AVIVO_DC_LUTB_WHITE_OFFSET_GREEN        0x6cd4
60 #define AVIVO_DC_LUTB_WHITE_OFFSET_RED          0x6cd8
61 
62 enum ofdrm_model {
63 	OFDRM_MODEL_UNKNOWN,
64 	OFDRM_MODEL_MACH64, /* ATI Mach64 */
65 	OFDRM_MODEL_RAGE128, /* ATI Rage128 */
66 	OFDRM_MODEL_RAGE_M3A, /* ATI Rage Mobility M3 Head A */
67 	OFDRM_MODEL_RAGE_M3B, /* ATI Rage Mobility M3 Head B */
68 	OFDRM_MODEL_RADEON, /* ATI Radeon */
69 	OFDRM_MODEL_GXT2000, /* IBM GXT2000 */
70 	OFDRM_MODEL_AVIVO, /* ATI R5xx */
71 	OFDRM_MODEL_QEMU, /* QEMU VGA */
72 };
73 
74 /*
75  * Helpers for display nodes
76  */
77 
78 static int display_get_validated_int(struct drm_device *dev, const char *name, uint32_t value)
79 {
80 	if (value > INT_MAX) {
81 		drm_err(dev, "invalid framebuffer %s of %u\n", name, value);
82 		return -EINVAL;
83 	}
84 	return (int)value;
85 }
86 
87 static int display_get_validated_int0(struct drm_device *dev, const char *name, uint32_t value)
88 {
89 	if (!value) {
90 		drm_err(dev, "invalid framebuffer %s of %u\n", name, value);
91 		return -EINVAL;
92 	}
93 	return display_get_validated_int(dev, name, value);
94 }
95 
96 static const struct drm_format_info *display_get_validated_format(struct drm_device *dev,
97 								  u32 depth, bool big_endian)
98 {
99 	const struct drm_format_info *info;
100 	u32 format;
101 
102 	switch (depth) {
103 	case 8:
104 		format = drm_mode_legacy_fb_format(8, 8);
105 		break;
106 	case 15:
107 	case 16:
108 		format = drm_mode_legacy_fb_format(16, depth);
109 		break;
110 	case 32:
111 		format = drm_mode_legacy_fb_format(32, 24);
112 		break;
113 	default:
114 		drm_err(dev, "unsupported framebuffer depth %u\n", depth);
115 		return ERR_PTR(-EINVAL);
116 	}
117 
118 	/*
119 	 * DRM formats assume little-endian byte order. Update the format
120 	 * if the scanout buffer uses big-endian ordering.
121 	 */
122 	if (big_endian) {
123 		switch (format) {
124 		case DRM_FORMAT_XRGB8888:
125 			format = DRM_FORMAT_BGRX8888;
126 			break;
127 		case DRM_FORMAT_ARGB8888:
128 			format = DRM_FORMAT_BGRA8888;
129 			break;
130 		case DRM_FORMAT_RGB565:
131 			format = DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN;
132 			break;
133 		case DRM_FORMAT_XRGB1555:
134 			format = DRM_FORMAT_XRGB1555 | DRM_FORMAT_BIG_ENDIAN;
135 			break;
136 		default:
137 			break;
138 		}
139 	}
140 
141 	info = drm_format_info(format);
142 	if (!info) {
143 		drm_err(dev, "cannot find framebuffer format for depth %u\n", depth);
144 		return ERR_PTR(-EINVAL);
145 	}
146 
147 	return info;
148 }
149 
150 static int display_read_u32_of(struct drm_device *dev, struct device_node *of_node,
151 			       const char *name, u32 *value)
152 {
153 	int ret = of_property_read_u32(of_node, name, value);
154 
155 	if (ret)
156 		drm_err(dev, "cannot parse framebuffer %s: error %d\n", name, ret);
157 	return ret;
158 }
159 
160 static bool display_get_big_endian_of(struct drm_device *dev, struct device_node *of_node)
161 {
162 	bool big_endian;
163 
164 #ifdef __BIG_ENDIAN
165 	big_endian = true;
166 	if (of_get_property(of_node, "little-endian", NULL))
167 		big_endian = false;
168 #else
169 	big_endian = false;
170 	if (of_get_property(of_node, "big-endian", NULL))
171 		big_endian = true;
172 #endif
173 
174 	return big_endian;
175 }
176 
177 static int display_get_width_of(struct drm_device *dev, struct device_node *of_node)
178 {
179 	u32 width;
180 	int ret = display_read_u32_of(dev, of_node, "width", &width);
181 
182 	if (ret)
183 		return ret;
184 	return display_get_validated_int0(dev, "width", width);
185 }
186 
187 static int display_get_height_of(struct drm_device *dev, struct device_node *of_node)
188 {
189 	u32 height;
190 	int ret = display_read_u32_of(dev, of_node, "height", &height);
191 
192 	if (ret)
193 		return ret;
194 	return display_get_validated_int0(dev, "height", height);
195 }
196 
197 static int display_get_depth_of(struct drm_device *dev, struct device_node *of_node)
198 {
199 	u32 depth;
200 	int ret = display_read_u32_of(dev, of_node, "depth", &depth);
201 
202 	if (ret)
203 		return ret;
204 	return display_get_validated_int0(dev, "depth", depth);
205 }
206 
207 static int display_get_linebytes_of(struct drm_device *dev, struct device_node *of_node)
208 {
209 	u32 linebytes;
210 	int ret = display_read_u32_of(dev, of_node, "linebytes", &linebytes);
211 
212 	if (ret)
213 		return ret;
214 	return display_get_validated_int(dev, "linebytes", linebytes);
215 }
216 
217 static u64 display_get_address_of(struct drm_device *dev, struct device_node *of_node)
218 {
219 	u32 address;
220 	int ret;
221 
222 	/*
223 	 * Not all devices provide an address property, it's not
224 	 * a bug if this fails. The driver will try to find the
225 	 * framebuffer base address from the device's memory regions.
226 	 */
227 	ret = of_property_read_u32(of_node, "address", &address);
228 	if (ret)
229 		return OF_BAD_ADDR;
230 
231 	return address;
232 }
233 
234 static bool is_avivo(u32 vendor, u32 device)
235 {
236 	/* This will match most R5xx */
237 	return (vendor == PCI_VENDOR_ID_ATI) &&
238 	       ((device >= PCI_VENDOR_ID_ATI_R520 && device < 0x7800) ||
239 		(PCI_VENDOR_ID_ATI_R600 >= 0x9400));
240 }
241 
242 static enum ofdrm_model display_get_model_of(struct drm_device *dev, struct device_node *of_node)
243 {
244 	enum ofdrm_model model = OFDRM_MODEL_UNKNOWN;
245 
246 	if (of_node_name_prefix(of_node, "ATY,Rage128")) {
247 		model = OFDRM_MODEL_RAGE128;
248 	} else if (of_node_name_prefix(of_node, "ATY,RageM3pA") ||
249 		   of_node_name_prefix(of_node, "ATY,RageM3p12A")) {
250 		model = OFDRM_MODEL_RAGE_M3A;
251 	} else if (of_node_name_prefix(of_node, "ATY,RageM3pB")) {
252 		model = OFDRM_MODEL_RAGE_M3B;
253 	} else if (of_node_name_prefix(of_node, "ATY,Rage6")) {
254 		model = OFDRM_MODEL_RADEON;
255 	} else if (of_node_name_prefix(of_node, "ATY,")) {
256 		return OFDRM_MODEL_MACH64;
257 	} else if (of_device_is_compatible(of_node, "pci1014,b7") ||
258 		   of_device_is_compatible(of_node, "pci1014,21c")) {
259 		model = OFDRM_MODEL_GXT2000;
260 	} else if (of_node_name_prefix(of_node, "vga,Display-")) {
261 		struct device_node *of_parent;
262 		const __be32 *vendor_p, *device_p;
263 
264 		/* Look for AVIVO initialized by SLOF */
265 		of_parent = of_get_parent(of_node);
266 		vendor_p = of_get_property(of_parent, "vendor-id", NULL);
267 		device_p = of_get_property(of_parent, "device-id", NULL);
268 		if (vendor_p && device_p) {
269 			u32 vendor = be32_to_cpup(vendor_p);
270 			u32 device = be32_to_cpup(device_p);
271 
272 			if (is_avivo(vendor, device))
273 				model = OFDRM_MODEL_AVIVO;
274 		}
275 		of_node_put(of_parent);
276 	} else if (of_device_is_compatible(of_node, "qemu,std-vga")) {
277 		model = OFDRM_MODEL_QEMU;
278 	}
279 
280 	return model;
281 }
282 
283 /*
284  * Open Firmware display device
285  */
286 
287 struct ofdrm_device;
288 
289 struct ofdrm_device_funcs {
290 	void __iomem *(*cmap_ioremap)(struct ofdrm_device *odev,
291 				      struct device_node *of_node,
292 				      u64 fb_bas);
293 	void (*cmap_write)(struct ofdrm_device *odev, unsigned char index,
294 			   unsigned char r, unsigned char g, unsigned char b);
295 };
296 
297 struct ofdrm_device {
298 	struct drm_device dev;
299 	struct platform_device *pdev;
300 
301 	const struct ofdrm_device_funcs *funcs;
302 
303 	/* firmware-buffer settings */
304 	struct iosys_map screen_base;
305 	struct drm_display_mode mode;
306 	const struct drm_format_info *format;
307 	unsigned int pitch;
308 
309 	/* colormap */
310 	void __iomem *cmap_base;
311 
312 	/* modesetting */
313 	uint32_t formats[8];
314 	struct drm_plane primary_plane;
315 	struct drm_crtc crtc;
316 	struct drm_encoder encoder;
317 	struct drm_connector connector;
318 };
319 
320 static struct ofdrm_device *ofdrm_device_of_dev(struct drm_device *dev)
321 {
322 	return container_of(dev, struct ofdrm_device, dev);
323 }
324 
325 /*
326  * Hardware
327  */
328 
329 #if defined(CONFIG_PCI)
330 static struct pci_dev *display_get_pci_dev_of(struct drm_device *dev, struct device_node *of_node)
331 {
332 	const __be32 *vendor_p, *device_p;
333 	u32 vendor, device;
334 	struct pci_dev *pcidev;
335 
336 	vendor_p = of_get_property(of_node, "vendor-id", NULL);
337 	if (!vendor_p)
338 		return ERR_PTR(-ENODEV);
339 	vendor = be32_to_cpup(vendor_p);
340 
341 	device_p = of_get_property(of_node, "device-id", NULL);
342 	if (!device_p)
343 		return ERR_PTR(-ENODEV);
344 	device = be32_to_cpup(device_p);
345 
346 	pcidev = pci_get_device(vendor, device, NULL);
347 	if (!pcidev)
348 		return ERR_PTR(-ENODEV);
349 
350 	return pcidev;
351 }
352 
353 static void ofdrm_pci_release(void *data)
354 {
355 	struct pci_dev *pcidev = data;
356 
357 	pci_disable_device(pcidev);
358 }
359 
360 static int ofdrm_device_init_pci(struct ofdrm_device *odev)
361 {
362 	struct drm_device *dev = &odev->dev;
363 	struct platform_device *pdev = to_platform_device(dev->dev);
364 	struct device_node *of_node = pdev->dev.of_node;
365 	struct pci_dev *pcidev;
366 	int ret;
367 
368 	/*
369 	 * Never use pcim_ or other managed helpers on the returned PCI
370 	 * device. Otherwise, probing the native driver will fail for
371 	 * resource conflicts. PCI-device management has to be tied to
372 	 * the lifetime of the platform device until the native driver
373 	 * takes over.
374 	 */
375 	pcidev = display_get_pci_dev_of(dev, of_node);
376 	if (IS_ERR(pcidev))
377 		return 0; /* no PCI device found; ignore the error */
378 
379 	ret = pci_enable_device(pcidev);
380 	if (ret) {
381 		drm_err(dev, "pci_enable_device(%s) failed: %d\n",
382 			dev_name(&pcidev->dev), ret);
383 		return ret;
384 	}
385 	ret = devm_add_action_or_reset(&pdev->dev, ofdrm_pci_release, pcidev);
386 	if (ret)
387 		return ret;
388 
389 	return 0;
390 }
391 #else
392 static int ofdrm_device_init_pci(struct ofdrm_device *odev)
393 {
394 	return 0;
395 }
396 #endif
397 
398 /*
399  *  OF display settings
400  */
401 
402 static struct resource *ofdrm_find_fb_resource(struct ofdrm_device *odev,
403 					       struct resource *fb_res)
404 {
405 	struct platform_device *pdev = to_platform_device(odev->dev.dev);
406 	struct resource *res, *max_res = NULL;
407 	u32 i;
408 
409 	for (i = 0; pdev->num_resources; ++i) {
410 		res = platform_get_resource(pdev, IORESOURCE_MEM, i);
411 		if (!res)
412 			break; /* all resources processed */
413 		if (resource_size(res) < resource_size(fb_res))
414 			continue; /* resource too small */
415 		if (fb_res->start && resource_contains(res, fb_res))
416 			return res; /* resource contains framebuffer */
417 		if (!max_res || resource_size(res) > resource_size(max_res))
418 			max_res = res; /* store largest resource as fallback */
419 	}
420 
421 	return max_res;
422 }
423 
424 /*
425  * Colormap / Palette
426  */
427 
428 static void __iomem *get_cmap_address_of(struct ofdrm_device *odev, struct device_node *of_node,
429 					 int bar_no, unsigned long offset, unsigned long size)
430 {
431 	struct drm_device *dev = &odev->dev;
432 	const __be32 *addr_p;
433 	u64 max_size, address;
434 	unsigned int flags;
435 	void __iomem *mem;
436 
437 	addr_p = of_get_pci_address(of_node, bar_no, &max_size, &flags);
438 	if (!addr_p)
439 		addr_p = of_get_address(of_node, bar_no, &max_size, &flags);
440 	if (!addr_p)
441 		return IOMEM_ERR_PTR(-ENODEV);
442 
443 	if ((flags & (IORESOURCE_IO | IORESOURCE_MEM)) == 0)
444 		return IOMEM_ERR_PTR(-ENODEV);
445 
446 	if ((offset + size) >= max_size)
447 		return IOMEM_ERR_PTR(-ENODEV);
448 
449 	address = of_translate_address(of_node, addr_p);
450 	if (address == OF_BAD_ADDR)
451 		return IOMEM_ERR_PTR(-ENODEV);
452 
453 	mem = devm_ioremap(dev->dev, address + offset, size);
454 	if (!mem)
455 		return IOMEM_ERR_PTR(-ENOMEM);
456 
457 	return mem;
458 }
459 
460 static void __iomem *ofdrm_mach64_cmap_ioremap(struct ofdrm_device *odev,
461 					       struct device_node *of_node,
462 					       u64 fb_base)
463 {
464 	struct drm_device *dev = &odev->dev;
465 	u64 address;
466 	void __iomem *cmap_base;
467 
468 	address = fb_base & 0xff000000ul;
469 	address += 0x7ff000;
470 
471 	cmap_base = devm_ioremap(dev->dev, address, 0x1000);
472 	if (!cmap_base)
473 		return IOMEM_ERR_PTR(-ENOMEM);
474 
475 	return cmap_base;
476 }
477 
478 static void ofdrm_mach64_cmap_write(struct ofdrm_device *odev, unsigned char index,
479 				    unsigned char r, unsigned char g, unsigned char b)
480 {
481 	void __iomem *addr = odev->cmap_base + 0xcc0;
482 	void __iomem *data = odev->cmap_base + 0xcc0 + 1;
483 
484 	writeb(index, addr);
485 	writeb(r, data);
486 	writeb(g, data);
487 	writeb(b, data);
488 }
489 
490 static void __iomem *ofdrm_rage128_cmap_ioremap(struct ofdrm_device *odev,
491 						struct device_node *of_node,
492 						u64 fb_base)
493 {
494 	return get_cmap_address_of(odev, of_node, 2, 0, 0x1fff);
495 }
496 
497 static void ofdrm_rage128_cmap_write(struct ofdrm_device *odev, unsigned char index,
498 				     unsigned char r, unsigned char g, unsigned char b)
499 {
500 	void __iomem *addr = odev->cmap_base + 0xb0;
501 	void __iomem *data = odev->cmap_base + 0xb4;
502 	u32 color = (r << 16) | (g << 8) | b;
503 
504 	writeb(index, addr);
505 	writel(color, data);
506 }
507 
508 static void __iomem *ofdrm_rage_m3a_cmap_ioremap(struct ofdrm_device *odev,
509 						 struct device_node *of_node,
510 						 u64 fb_base)
511 {
512 	return get_cmap_address_of(odev, of_node, 2, 0, 0x1fff);
513 }
514 
515 static void ofdrm_rage_m3a_cmap_write(struct ofdrm_device *odev, unsigned char index,
516 				      unsigned char r, unsigned char g, unsigned char b)
517 {
518 	void __iomem *dac_ctl = odev->cmap_base + 0x58;
519 	void __iomem *addr = odev->cmap_base + 0xb0;
520 	void __iomem *data = odev->cmap_base + 0xb4;
521 	u32 color = (r << 16) | (g << 8) | b;
522 	u32 val;
523 
524 	/* Clear PALETTE_ACCESS_CNTL in DAC_CNTL */
525 	val = readl(dac_ctl);
526 	val &= ~0x20;
527 	writel(val, dac_ctl);
528 
529 	/* Set color at palette index */
530 	writeb(index, addr);
531 	writel(color, data);
532 }
533 
534 static void __iomem *ofdrm_rage_m3b_cmap_ioremap(struct ofdrm_device *odev,
535 						 struct device_node *of_node,
536 						 u64 fb_base)
537 {
538 	return get_cmap_address_of(odev, of_node, 2, 0, 0x1fff);
539 }
540 
541 static void ofdrm_rage_m3b_cmap_write(struct ofdrm_device *odev, unsigned char index,
542 				      unsigned char r, unsigned char g, unsigned char b)
543 {
544 	void __iomem *dac_ctl = odev->cmap_base + 0x58;
545 	void __iomem *addr = odev->cmap_base + 0xb0;
546 	void __iomem *data = odev->cmap_base + 0xb4;
547 	u32 color = (r << 16) | (g << 8) | b;
548 	u32 val;
549 
550 	/* Set PALETTE_ACCESS_CNTL in DAC_CNTL */
551 	val = readl(dac_ctl);
552 	val |= 0x20;
553 	writel(val, dac_ctl);
554 
555 	/* Set color at palette index */
556 	writeb(index, addr);
557 	writel(color, data);
558 }
559 
560 static void __iomem *ofdrm_radeon_cmap_ioremap(struct ofdrm_device *odev,
561 					       struct device_node *of_node,
562 					       u64 fb_base)
563 {
564 	return get_cmap_address_of(odev, of_node, 1, 0, 0x1fff);
565 }
566 
567 static void __iomem *ofdrm_gxt2000_cmap_ioremap(struct ofdrm_device *odev,
568 						struct device_node *of_node,
569 						u64 fb_base)
570 {
571 	return get_cmap_address_of(odev, of_node, 0, 0x6000, 0x1000);
572 }
573 
574 static void ofdrm_gxt2000_cmap_write(struct ofdrm_device *odev, unsigned char index,
575 				     unsigned char r, unsigned char g, unsigned char b)
576 {
577 	void __iomem *data = ((unsigned int __iomem *)odev->cmap_base) + index;
578 	u32 color = (r << 16) | (g << 8) | b;
579 
580 	writel(color, data);
581 }
582 
583 static void __iomem *ofdrm_avivo_cmap_ioremap(struct ofdrm_device *odev,
584 					      struct device_node *of_node,
585 					      u64 fb_base)
586 {
587 	struct device_node *of_parent;
588 	void __iomem *cmap_base;
589 
590 	of_parent = of_get_parent(of_node);
591 	cmap_base = get_cmap_address_of(odev, of_parent, 0, 0, 0x10000);
592 	of_node_put(of_parent);
593 
594 	return cmap_base;
595 }
596 
597 static void ofdrm_avivo_cmap_write(struct ofdrm_device *odev, unsigned char index,
598 				   unsigned char r, unsigned char g, unsigned char b)
599 {
600 	void __iomem *lutsel = odev->cmap_base + AVIVO_DC_LUT_RW_SELECT;
601 	void __iomem *addr = odev->cmap_base + AVIVO_DC_LUT_RW_INDEX;
602 	void __iomem *data = odev->cmap_base + AVIVO_DC_LUT_30_COLOR;
603 	u32 color = (r << 22) | (g << 12) | (b << 2);
604 
605 	/* Write to both LUTs for now */
606 
607 	writel(1, lutsel);
608 	writeb(index, addr);
609 	writel(color, data);
610 
611 	writel(0, lutsel);
612 	writeb(index, addr);
613 	writel(color, data);
614 }
615 
616 static void __iomem *ofdrm_qemu_cmap_ioremap(struct ofdrm_device *odev,
617 					     struct device_node *of_node,
618 					     u64 fb_base)
619 {
620 	static const __be32 io_of_addr[3] = {
621 		cpu_to_be32(0x01000000),
622 		cpu_to_be32(0x00),
623 		cpu_to_be32(0x00),
624 	};
625 
626 	struct drm_device *dev = &odev->dev;
627 	u64 address;
628 	void __iomem *cmap_base;
629 
630 	address = of_translate_address(of_node, io_of_addr);
631 	if (address == OF_BAD_ADDR)
632 		return IOMEM_ERR_PTR(-ENODEV);
633 
634 	cmap_base = devm_ioremap(dev->dev, address + 0x3c8, 2);
635 	if (!cmap_base)
636 		return IOMEM_ERR_PTR(-ENOMEM);
637 
638 	return cmap_base;
639 }
640 
641 static void ofdrm_qemu_cmap_write(struct ofdrm_device *odev, unsigned char index,
642 				  unsigned char r, unsigned char g, unsigned char b)
643 {
644 	void __iomem *addr = odev->cmap_base;
645 	void __iomem *data = odev->cmap_base + 1;
646 
647 	writeb(index, addr);
648 	writeb(r, data);
649 	writeb(g, data);
650 	writeb(b, data);
651 }
652 
653 static void ofdrm_device_set_gamma_linear(struct ofdrm_device *odev,
654 					  const struct drm_format_info *format)
655 {
656 	struct drm_device *dev = &odev->dev;
657 	int i;
658 
659 	switch (format->format) {
660 	case DRM_FORMAT_RGB565:
661 	case DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN:
662 		/* Use better interpolation, to take 32 values from 0 to 255 */
663 		for (i = 0; i < OFDRM_GAMMA_LUT_SIZE / 8; i++) {
664 			unsigned char r = i * 8 + i / 4;
665 			unsigned char g = i * 4 + i / 16;
666 			unsigned char b = i * 8 + i / 4;
667 
668 			odev->funcs->cmap_write(odev, i, r, g, b);
669 		}
670 		/* Green has one more bit, so add padding with 0 for red and blue. */
671 		for (i = OFDRM_GAMMA_LUT_SIZE / 8; i < OFDRM_GAMMA_LUT_SIZE / 4; i++) {
672 			unsigned char r = 0;
673 			unsigned char g = i * 4 + i / 16;
674 			unsigned char b = 0;
675 
676 			odev->funcs->cmap_write(odev, i, r, g, b);
677 		}
678 		break;
679 	case DRM_FORMAT_XRGB8888:
680 	case DRM_FORMAT_BGRX8888:
681 		for (i = 0; i < OFDRM_GAMMA_LUT_SIZE; i++)
682 			odev->funcs->cmap_write(odev, i, i, i, i);
683 		break;
684 	default:
685 		drm_warn_once(dev, "Unsupported format %p4cc for gamma correction\n",
686 			      &format->format);
687 		break;
688 	}
689 }
690 
691 static void ofdrm_device_set_gamma(struct ofdrm_device *odev,
692 				   const struct drm_format_info *format,
693 				   struct drm_color_lut *lut)
694 {
695 	struct drm_device *dev = &odev->dev;
696 	int i;
697 
698 	switch (format->format) {
699 	case DRM_FORMAT_RGB565:
700 	case DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN:
701 		/* Use better interpolation, to take 32 values from lut[0] to lut[255] */
702 		for (i = 0; i < OFDRM_GAMMA_LUT_SIZE / 8; i++) {
703 			unsigned char r = lut[i * 8 + i / 4].red >> 8;
704 			unsigned char g = lut[i * 4 + i / 16].green >> 8;
705 			unsigned char b = lut[i * 8 + i / 4].blue >> 8;
706 
707 			odev->funcs->cmap_write(odev, i, r, g, b);
708 		}
709 		/* Green has one more bit, so add padding with 0 for red and blue. */
710 		for (i = OFDRM_GAMMA_LUT_SIZE / 8; i < OFDRM_GAMMA_LUT_SIZE / 4; i++) {
711 			unsigned char r = 0;
712 			unsigned char g = lut[i * 4 + i / 16].green >> 8;
713 			unsigned char b = 0;
714 
715 			odev->funcs->cmap_write(odev, i, r, g, b);
716 		}
717 		break;
718 	case DRM_FORMAT_XRGB8888:
719 	case DRM_FORMAT_BGRX8888:
720 		for (i = 0; i < OFDRM_GAMMA_LUT_SIZE; i++) {
721 			unsigned char r = lut[i].red >> 8;
722 			unsigned char g = lut[i].green >> 8;
723 			unsigned char b = lut[i].blue >> 8;
724 
725 			odev->funcs->cmap_write(odev, i, r, g, b);
726 		}
727 		break;
728 	default:
729 		drm_warn_once(dev, "Unsupported format %p4cc for gamma correction\n",
730 			      &format->format);
731 		break;
732 	}
733 }
734 
735 /*
736  * Modesetting
737  */
738 
739 struct ofdrm_crtc_state {
740 	struct drm_crtc_state base;
741 
742 	/* Primary-plane format; required for color mgmt. */
743 	const struct drm_format_info *format;
744 };
745 
746 static struct ofdrm_crtc_state *to_ofdrm_crtc_state(struct drm_crtc_state *base)
747 {
748 	return container_of(base, struct ofdrm_crtc_state, base);
749 }
750 
751 static void ofdrm_crtc_state_destroy(struct ofdrm_crtc_state *ofdrm_crtc_state)
752 {
753 	__drm_atomic_helper_crtc_destroy_state(&ofdrm_crtc_state->base);
754 	kfree(ofdrm_crtc_state);
755 }
756 
757 static const uint64_t ofdrm_primary_plane_format_modifiers[] = {
758 	DRM_FORMAT_MOD_LINEAR,
759 	DRM_FORMAT_MOD_INVALID
760 };
761 
762 static int ofdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
763 						   struct drm_atomic_state *new_state)
764 {
765 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(new_state, plane);
766 	struct drm_framebuffer *new_fb = new_plane_state->fb;
767 	struct drm_crtc *new_crtc = new_plane_state->crtc;
768 	struct drm_crtc_state *new_crtc_state = NULL;
769 	struct ofdrm_crtc_state *new_ofdrm_crtc_state;
770 	int ret;
771 
772 	if (new_crtc)
773 		new_crtc_state = drm_atomic_get_new_crtc_state(new_state, new_plane_state->crtc);
774 
775 	ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
776 						  DRM_PLANE_NO_SCALING,
777 						  DRM_PLANE_NO_SCALING,
778 						  false, false);
779 	if (ret)
780 		return ret;
781 	else if (!new_plane_state->visible)
782 		return 0;
783 
784 	new_crtc_state = drm_atomic_get_new_crtc_state(new_state, new_plane_state->crtc);
785 
786 	new_ofdrm_crtc_state = to_ofdrm_crtc_state(new_crtc_state);
787 	new_ofdrm_crtc_state->format = new_fb->format;
788 
789 	return 0;
790 }
791 
792 static void ofdrm_primary_plane_helper_atomic_update(struct drm_plane *plane,
793 						     struct drm_atomic_state *state)
794 {
795 	struct drm_device *dev = plane->dev;
796 	struct ofdrm_device *odev = ofdrm_device_of_dev(dev);
797 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
798 	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
799 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
800 	struct drm_framebuffer *fb = plane_state->fb;
801 	unsigned int dst_pitch = odev->pitch;
802 	const struct drm_format_info *dst_format = odev->format;
803 	struct drm_atomic_helper_damage_iter iter;
804 	struct drm_rect damage;
805 	int ret, idx;
806 
807 	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
808 	if (ret)
809 		return;
810 
811 	if (!drm_dev_enter(dev, &idx))
812 		goto out_drm_gem_fb_end_cpu_access;
813 
814 	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
815 	drm_atomic_for_each_plane_damage(&iter, &damage) {
816 		struct iosys_map dst = odev->screen_base;
817 		struct drm_rect dst_clip = plane_state->dst;
818 
819 		if (!drm_rect_intersect(&dst_clip, &damage))
820 			continue;
821 
822 		iosys_map_incr(&dst, drm_fb_clip_offset(dst_pitch, dst_format, &dst_clip));
823 		drm_fb_blit(&dst, &dst_pitch, dst_format->format, shadow_plane_state->data, fb,
824 			    &damage);
825 	}
826 
827 	drm_dev_exit(idx);
828 out_drm_gem_fb_end_cpu_access:
829 	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
830 }
831 
832 static void ofdrm_primary_plane_helper_atomic_disable(struct drm_plane *plane,
833 						      struct drm_atomic_state *state)
834 {
835 	struct drm_device *dev = plane->dev;
836 	struct ofdrm_device *odev = ofdrm_device_of_dev(dev);
837 	struct iosys_map dst = odev->screen_base;
838 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
839 	void __iomem *dst_vmap = dst.vaddr_iomem; /* TODO: Use mapping abstraction */
840 	unsigned int dst_pitch = odev->pitch;
841 	const struct drm_format_info *dst_format = odev->format;
842 	struct drm_rect dst_clip;
843 	unsigned long lines, linepixels, i;
844 	int idx;
845 
846 	drm_rect_init(&dst_clip,
847 		      plane_state->src_x >> 16, plane_state->src_y >> 16,
848 		      plane_state->src_w >> 16, plane_state->src_h >> 16);
849 
850 	lines = drm_rect_height(&dst_clip);
851 	linepixels = drm_rect_width(&dst_clip);
852 
853 	if (!drm_dev_enter(dev, &idx))
854 		return;
855 
856 	/* Clear buffer to black if disabled */
857 	dst_vmap += drm_fb_clip_offset(dst_pitch, dst_format, &dst_clip);
858 	for (i = 0; i < lines; ++i) {
859 		memset_io(dst_vmap, 0, linepixels * dst_format->cpp[0]);
860 		dst_vmap += dst_pitch;
861 	}
862 
863 	drm_dev_exit(idx);
864 }
865 
866 static const struct drm_plane_helper_funcs ofdrm_primary_plane_helper_funcs = {
867 	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
868 	.atomic_check = ofdrm_primary_plane_helper_atomic_check,
869 	.atomic_update = ofdrm_primary_plane_helper_atomic_update,
870 	.atomic_disable = ofdrm_primary_plane_helper_atomic_disable,
871 };
872 
873 static const struct drm_plane_funcs ofdrm_primary_plane_funcs = {
874 	.update_plane = drm_atomic_helper_update_plane,
875 	.disable_plane = drm_atomic_helper_disable_plane,
876 	.destroy = drm_plane_cleanup,
877 	DRM_GEM_SHADOW_PLANE_FUNCS,
878 };
879 
880 static enum drm_mode_status ofdrm_crtc_helper_mode_valid(struct drm_crtc *crtc,
881 							 const struct drm_display_mode *mode)
882 {
883 	struct ofdrm_device *odev = ofdrm_device_of_dev(crtc->dev);
884 
885 	return drm_crtc_helper_mode_valid_fixed(crtc, mode, &odev->mode);
886 }
887 
888 static int ofdrm_crtc_helper_atomic_check(struct drm_crtc *crtc,
889 					  struct drm_atomic_state *new_state)
890 {
891 	static const size_t gamma_lut_length = OFDRM_GAMMA_LUT_SIZE * sizeof(struct drm_color_lut);
892 
893 	struct drm_device *dev = crtc->dev;
894 	struct drm_crtc_state *new_crtc_state = drm_atomic_get_new_crtc_state(new_state, crtc);
895 	int ret;
896 
897 	if (!new_crtc_state->enable)
898 		return 0;
899 
900 	ret = drm_atomic_helper_check_crtc_primary_plane(new_crtc_state);
901 	if (ret)
902 		return ret;
903 
904 	if (new_crtc_state->color_mgmt_changed) {
905 		struct drm_property_blob *gamma_lut = new_crtc_state->gamma_lut;
906 
907 		if (gamma_lut && (gamma_lut->length != gamma_lut_length)) {
908 			drm_dbg(dev, "Incorrect gamma_lut length %zu\n", gamma_lut->length);
909 			return -EINVAL;
910 		}
911 	}
912 
913 	return 0;
914 }
915 
916 static void ofdrm_crtc_helper_atomic_flush(struct drm_crtc *crtc, struct drm_atomic_state *state)
917 {
918 	struct ofdrm_device *odev = ofdrm_device_of_dev(crtc->dev);
919 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
920 	struct ofdrm_crtc_state *ofdrm_crtc_state = to_ofdrm_crtc_state(crtc_state);
921 
922 	if (crtc_state->enable && crtc_state->color_mgmt_changed) {
923 		const struct drm_format_info *format = ofdrm_crtc_state->format;
924 
925 		if (crtc_state->gamma_lut)
926 			ofdrm_device_set_gamma(odev, format, crtc_state->gamma_lut->data);
927 		else
928 			ofdrm_device_set_gamma_linear(odev, format);
929 	}
930 }
931 
932 /*
933  * The CRTC is always enabled. Screen updates are performed by
934  * the primary plane's atomic_update function. Disabling clears
935  * the screen in the primary plane's atomic_disable function.
936  */
937 static const struct drm_crtc_helper_funcs ofdrm_crtc_helper_funcs = {
938 	.mode_valid = ofdrm_crtc_helper_mode_valid,
939 	.atomic_check = ofdrm_crtc_helper_atomic_check,
940 	.atomic_flush = ofdrm_crtc_helper_atomic_flush,
941 };
942 
943 static void ofdrm_crtc_reset(struct drm_crtc *crtc)
944 {
945 	struct ofdrm_crtc_state *ofdrm_crtc_state =
946 		kzalloc(sizeof(*ofdrm_crtc_state), GFP_KERNEL);
947 
948 	if (crtc->state)
949 		ofdrm_crtc_state_destroy(to_ofdrm_crtc_state(crtc->state));
950 
951 	if (ofdrm_crtc_state)
952 		__drm_atomic_helper_crtc_reset(crtc, &ofdrm_crtc_state->base);
953 	else
954 		__drm_atomic_helper_crtc_reset(crtc, NULL);
955 }
956 
957 static struct drm_crtc_state *ofdrm_crtc_atomic_duplicate_state(struct drm_crtc *crtc)
958 {
959 	struct drm_device *dev = crtc->dev;
960 	struct drm_crtc_state *crtc_state = crtc->state;
961 	struct ofdrm_crtc_state *new_ofdrm_crtc_state;
962 	struct ofdrm_crtc_state *ofdrm_crtc_state;
963 
964 	if (drm_WARN_ON(dev, !crtc_state))
965 		return NULL;
966 
967 	new_ofdrm_crtc_state = kzalloc(sizeof(*new_ofdrm_crtc_state), GFP_KERNEL);
968 	if (!new_ofdrm_crtc_state)
969 		return NULL;
970 
971 	ofdrm_crtc_state = to_ofdrm_crtc_state(crtc_state);
972 
973 	__drm_atomic_helper_crtc_duplicate_state(crtc, &new_ofdrm_crtc_state->base);
974 	new_ofdrm_crtc_state->format = ofdrm_crtc_state->format;
975 
976 	return &new_ofdrm_crtc_state->base;
977 }
978 
979 static void ofdrm_crtc_atomic_destroy_state(struct drm_crtc *crtc,
980 					    struct drm_crtc_state *crtc_state)
981 {
982 	ofdrm_crtc_state_destroy(to_ofdrm_crtc_state(crtc_state));
983 }
984 
985 static const struct drm_crtc_funcs ofdrm_crtc_funcs = {
986 	.reset = ofdrm_crtc_reset,
987 	.destroy = drm_crtc_cleanup,
988 	.set_config = drm_atomic_helper_set_config,
989 	.page_flip = drm_atomic_helper_page_flip,
990 	.atomic_duplicate_state = ofdrm_crtc_atomic_duplicate_state,
991 	.atomic_destroy_state = ofdrm_crtc_atomic_destroy_state,
992 };
993 
994 static int ofdrm_connector_helper_get_modes(struct drm_connector *connector)
995 {
996 	struct ofdrm_device *odev = ofdrm_device_of_dev(connector->dev);
997 
998 	return drm_connector_helper_get_modes_fixed(connector, &odev->mode);
999 }
1000 
1001 static const struct drm_connector_helper_funcs ofdrm_connector_helper_funcs = {
1002 	.get_modes = ofdrm_connector_helper_get_modes,
1003 };
1004 
1005 static const struct drm_connector_funcs ofdrm_connector_funcs = {
1006 	.reset = drm_atomic_helper_connector_reset,
1007 	.fill_modes = drm_helper_probe_single_connector_modes,
1008 	.destroy = drm_connector_cleanup,
1009 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
1010 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
1011 };
1012 
1013 static const struct drm_mode_config_funcs ofdrm_mode_config_funcs = {
1014 	.fb_create = drm_gem_fb_create_with_dirty,
1015 	.atomic_check = drm_atomic_helper_check,
1016 	.atomic_commit = drm_atomic_helper_commit,
1017 };
1018 
1019 /*
1020  * Init / Cleanup
1021  */
1022 
1023 static const struct ofdrm_device_funcs ofdrm_unknown_device_funcs = {
1024 };
1025 
1026 static const struct ofdrm_device_funcs ofdrm_mach64_device_funcs = {
1027 	.cmap_ioremap = ofdrm_mach64_cmap_ioremap,
1028 	.cmap_write = ofdrm_mach64_cmap_write,
1029 };
1030 
1031 static const struct ofdrm_device_funcs ofdrm_rage128_device_funcs = {
1032 	.cmap_ioremap = ofdrm_rage128_cmap_ioremap,
1033 	.cmap_write = ofdrm_rage128_cmap_write,
1034 };
1035 
1036 static const struct ofdrm_device_funcs ofdrm_rage_m3a_device_funcs = {
1037 	.cmap_ioremap = ofdrm_rage_m3a_cmap_ioremap,
1038 	.cmap_write = ofdrm_rage_m3a_cmap_write,
1039 };
1040 
1041 static const struct ofdrm_device_funcs ofdrm_rage_m3b_device_funcs = {
1042 	.cmap_ioremap = ofdrm_rage_m3b_cmap_ioremap,
1043 	.cmap_write = ofdrm_rage_m3b_cmap_write,
1044 };
1045 
1046 static const struct ofdrm_device_funcs ofdrm_radeon_device_funcs = {
1047 	.cmap_ioremap = ofdrm_radeon_cmap_ioremap,
1048 	.cmap_write = ofdrm_rage128_cmap_write, /* same as Rage128 */
1049 };
1050 
1051 static const struct ofdrm_device_funcs ofdrm_gxt2000_device_funcs = {
1052 	.cmap_ioremap = ofdrm_gxt2000_cmap_ioremap,
1053 	.cmap_write = ofdrm_gxt2000_cmap_write,
1054 };
1055 
1056 static const struct ofdrm_device_funcs ofdrm_avivo_device_funcs = {
1057 	.cmap_ioremap = ofdrm_avivo_cmap_ioremap,
1058 	.cmap_write = ofdrm_avivo_cmap_write,
1059 };
1060 
1061 static const struct ofdrm_device_funcs ofdrm_qemu_device_funcs = {
1062 	.cmap_ioremap = ofdrm_qemu_cmap_ioremap,
1063 	.cmap_write = ofdrm_qemu_cmap_write,
1064 };
1065 
1066 static struct drm_display_mode ofdrm_mode(unsigned int width, unsigned int height)
1067 {
1068 	/*
1069 	 * Assume a monitor resolution of 96 dpi to
1070 	 * get a somewhat reasonable screen size.
1071 	 */
1072 	const struct drm_display_mode mode = {
1073 		DRM_MODE_INIT(60, width, height,
1074 			      DRM_MODE_RES_MM(width, 96ul),
1075 			      DRM_MODE_RES_MM(height, 96ul))
1076 	};
1077 
1078 	return mode;
1079 }
1080 
1081 static struct ofdrm_device *ofdrm_device_create(struct drm_driver *drv,
1082 						struct platform_device *pdev)
1083 {
1084 	struct device_node *of_node = pdev->dev.of_node;
1085 	struct ofdrm_device *odev;
1086 	struct drm_device *dev;
1087 	enum ofdrm_model model;
1088 	bool big_endian;
1089 	int width, height, depth, linebytes;
1090 	const struct drm_format_info *format;
1091 	u64 address;
1092 	resource_size_t fb_size, fb_base, fb_pgbase, fb_pgsize;
1093 	struct resource *res, *mem;
1094 	void __iomem *screen_base;
1095 	struct drm_plane *primary_plane;
1096 	struct drm_crtc *crtc;
1097 	struct drm_encoder *encoder;
1098 	struct drm_connector *connector;
1099 	unsigned long max_width, max_height;
1100 	size_t nformats;
1101 	int ret;
1102 
1103 	odev = devm_drm_dev_alloc(&pdev->dev, drv, struct ofdrm_device, dev);
1104 	if (IS_ERR(odev))
1105 		return ERR_CAST(odev);
1106 	dev = &odev->dev;
1107 	platform_set_drvdata(pdev, dev);
1108 
1109 	ret = ofdrm_device_init_pci(odev);
1110 	if (ret)
1111 		return ERR_PTR(ret);
1112 
1113 	/*
1114 	 * OF display-node settings
1115 	 */
1116 
1117 	model = display_get_model_of(dev, of_node);
1118 	drm_dbg(dev, "detected model %d\n", model);
1119 
1120 	switch (model) {
1121 	case OFDRM_MODEL_UNKNOWN:
1122 		odev->funcs = &ofdrm_unknown_device_funcs;
1123 		break;
1124 	case OFDRM_MODEL_MACH64:
1125 		odev->funcs = &ofdrm_mach64_device_funcs;
1126 		break;
1127 	case OFDRM_MODEL_RAGE128:
1128 		odev->funcs = &ofdrm_rage128_device_funcs;
1129 		break;
1130 	case OFDRM_MODEL_RAGE_M3A:
1131 		odev->funcs = &ofdrm_rage_m3a_device_funcs;
1132 		break;
1133 	case OFDRM_MODEL_RAGE_M3B:
1134 		odev->funcs = &ofdrm_rage_m3b_device_funcs;
1135 		break;
1136 	case OFDRM_MODEL_RADEON:
1137 		odev->funcs = &ofdrm_radeon_device_funcs;
1138 		break;
1139 	case OFDRM_MODEL_GXT2000:
1140 		odev->funcs = &ofdrm_gxt2000_device_funcs;
1141 		break;
1142 	case OFDRM_MODEL_AVIVO:
1143 		odev->funcs = &ofdrm_avivo_device_funcs;
1144 		break;
1145 	case OFDRM_MODEL_QEMU:
1146 		odev->funcs = &ofdrm_qemu_device_funcs;
1147 		break;
1148 	}
1149 
1150 	big_endian = display_get_big_endian_of(dev, of_node);
1151 
1152 	width = display_get_width_of(dev, of_node);
1153 	if (width < 0)
1154 		return ERR_PTR(width);
1155 	height = display_get_height_of(dev, of_node);
1156 	if (height < 0)
1157 		return ERR_PTR(height);
1158 	depth = display_get_depth_of(dev, of_node);
1159 	if (depth < 0)
1160 		return ERR_PTR(depth);
1161 	linebytes = display_get_linebytes_of(dev, of_node);
1162 	if (linebytes < 0)
1163 		return ERR_PTR(linebytes);
1164 
1165 	format = display_get_validated_format(dev, depth, big_endian);
1166 	if (IS_ERR(format))
1167 		return ERR_CAST(format);
1168 	if (!linebytes) {
1169 		linebytes = drm_format_info_min_pitch(format, 0, width);
1170 		if (drm_WARN_ON(dev, !linebytes))
1171 			return ERR_PTR(-EINVAL);
1172 	}
1173 
1174 	fb_size = linebytes * height;
1175 
1176 	/*
1177 	 * Try to figure out the address of the framebuffer. Unfortunately, Open
1178 	 * Firmware doesn't provide a standard way to do so. All we can do is a
1179 	 * dodgy heuristic that happens to work in practice.
1180 	 *
1181 	 * On most machines, the "address" property contains what we need, though
1182 	 * not on Matrox cards found in IBM machines. What appears to give good
1183 	 * results is to go through the PCI ranges and pick one that encloses the
1184 	 * "address" property. If none match, we pick the largest.
1185 	 */
1186 	address = display_get_address_of(dev, of_node);
1187 	if (address != OF_BAD_ADDR) {
1188 		struct resource fb_res = DEFINE_RES_MEM(address, fb_size);
1189 
1190 		res = ofdrm_find_fb_resource(odev, &fb_res);
1191 		if (!res)
1192 			return ERR_PTR(-EINVAL);
1193 		if (resource_contains(res, &fb_res))
1194 			fb_base = address;
1195 		else
1196 			fb_base = res->start;
1197 	} else {
1198 		struct resource fb_res = DEFINE_RES_MEM(0u, fb_size);
1199 
1200 		res = ofdrm_find_fb_resource(odev, &fb_res);
1201 		if (!res)
1202 			return ERR_PTR(-EINVAL);
1203 		fb_base = res->start;
1204 	}
1205 
1206 	/*
1207 	 * I/O resources
1208 	 */
1209 
1210 	fb_pgbase = round_down(fb_base, PAGE_SIZE);
1211 	fb_pgsize = fb_base - fb_pgbase + round_up(fb_size, PAGE_SIZE);
1212 
1213 	ret = devm_aperture_acquire_from_firmware(dev, fb_pgbase, fb_pgsize);
1214 	if (ret) {
1215 		drm_err(dev, "could not acquire memory range %pr: error %d\n", &res, ret);
1216 		return ERR_PTR(ret);
1217 	}
1218 
1219 	mem = devm_request_mem_region(&pdev->dev, fb_pgbase, fb_pgsize, drv->name);
1220 	if (!mem) {
1221 		drm_warn(dev, "could not acquire memory region %pr\n", &res);
1222 		return ERR_PTR(-ENOMEM);
1223 	}
1224 
1225 	screen_base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
1226 	if (!screen_base)
1227 		return ERR_PTR(-ENOMEM);
1228 
1229 	if (odev->funcs->cmap_ioremap) {
1230 		void __iomem *cmap_base = odev->funcs->cmap_ioremap(odev, of_node, fb_base);
1231 
1232 		if (IS_ERR(cmap_base)) {
1233 			/* Don't fail; continue without colormap */
1234 			drm_warn(dev, "could not find colormap: error %ld\n", PTR_ERR(cmap_base));
1235 		} else {
1236 			odev->cmap_base = cmap_base;
1237 		}
1238 	}
1239 
1240 	/*
1241 	 * Firmware framebuffer
1242 	 */
1243 
1244 	iosys_map_set_vaddr_iomem(&odev->screen_base, screen_base);
1245 	odev->mode = ofdrm_mode(width, height);
1246 	odev->format = format;
1247 	odev->pitch = linebytes;
1248 
1249 	drm_dbg(dev, "display mode={" DRM_MODE_FMT "}\n", DRM_MODE_ARG(&odev->mode));
1250 	drm_dbg(dev, "framebuffer format=%p4cc, size=%dx%d, linebytes=%d byte\n",
1251 		&format->format, width, height, linebytes);
1252 
1253 	/*
1254 	 * Mode-setting pipeline
1255 	 */
1256 
1257 	ret = drmm_mode_config_init(dev);
1258 	if (ret)
1259 		return ERR_PTR(ret);
1260 
1261 	max_width = max_t(unsigned long, width, DRM_SHADOW_PLANE_MAX_WIDTH);
1262 	max_height = max_t(unsigned long, height, DRM_SHADOW_PLANE_MAX_HEIGHT);
1263 
1264 	dev->mode_config.min_width = width;
1265 	dev->mode_config.max_width = max_width;
1266 	dev->mode_config.min_height = height;
1267 	dev->mode_config.max_height = max_height;
1268 	dev->mode_config.funcs = &ofdrm_mode_config_funcs;
1269 	dev->mode_config.preferred_depth = format->depth;
1270 	dev->mode_config.quirk_addfb_prefer_host_byte_order = true;
1271 
1272 	/* Primary plane */
1273 
1274 	nformats = drm_fb_build_fourcc_list(dev, &format->format, 1,
1275 					    odev->formats, ARRAY_SIZE(odev->formats));
1276 
1277 	primary_plane = &odev->primary_plane;
1278 	ret = drm_universal_plane_init(dev, primary_plane, 0, &ofdrm_primary_plane_funcs,
1279 				       odev->formats, nformats,
1280 				       ofdrm_primary_plane_format_modifiers,
1281 				       DRM_PLANE_TYPE_PRIMARY, NULL);
1282 	if (ret)
1283 		return ERR_PTR(ret);
1284 	drm_plane_helper_add(primary_plane, &ofdrm_primary_plane_helper_funcs);
1285 	drm_plane_enable_fb_damage_clips(primary_plane);
1286 
1287 	/* CRTC */
1288 
1289 	crtc = &odev->crtc;
1290 	ret = drm_crtc_init_with_planes(dev, crtc, primary_plane, NULL,
1291 					&ofdrm_crtc_funcs, NULL);
1292 	if (ret)
1293 		return ERR_PTR(ret);
1294 	drm_crtc_helper_add(crtc, &ofdrm_crtc_helper_funcs);
1295 
1296 	if (odev->cmap_base) {
1297 		drm_mode_crtc_set_gamma_size(crtc, OFDRM_GAMMA_LUT_SIZE);
1298 		drm_crtc_enable_color_mgmt(crtc, 0, false, OFDRM_GAMMA_LUT_SIZE);
1299 	}
1300 
1301 	/* Encoder */
1302 
1303 	encoder = &odev->encoder;
1304 	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
1305 	if (ret)
1306 		return ERR_PTR(ret);
1307 	encoder->possible_crtcs = drm_crtc_mask(crtc);
1308 
1309 	/* Connector */
1310 
1311 	connector = &odev->connector;
1312 	ret = drm_connector_init(dev, connector, &ofdrm_connector_funcs,
1313 				 DRM_MODE_CONNECTOR_Unknown);
1314 	if (ret)
1315 		return ERR_PTR(ret);
1316 	drm_connector_helper_add(connector, &ofdrm_connector_helper_funcs);
1317 	drm_connector_set_panel_orientation_with_quirk(connector,
1318 						       DRM_MODE_PANEL_ORIENTATION_UNKNOWN,
1319 						       width, height);
1320 
1321 	ret = drm_connector_attach_encoder(connector, encoder);
1322 	if (ret)
1323 		return ERR_PTR(ret);
1324 
1325 	drm_mode_config_reset(dev);
1326 
1327 	return odev;
1328 }
1329 
1330 /*
1331  * DRM driver
1332  */
1333 
1334 DEFINE_DRM_GEM_FOPS(ofdrm_fops);
1335 
1336 static struct drm_driver ofdrm_driver = {
1337 	DRM_GEM_SHMEM_DRIVER_OPS,
1338 	.name			= DRIVER_NAME,
1339 	.desc			= DRIVER_DESC,
1340 	.date			= DRIVER_DATE,
1341 	.major			= DRIVER_MAJOR,
1342 	.minor			= DRIVER_MINOR,
1343 	.driver_features	= DRIVER_ATOMIC | DRIVER_GEM | DRIVER_MODESET,
1344 	.fops			= &ofdrm_fops,
1345 };
1346 
1347 /*
1348  * Platform driver
1349  */
1350 
1351 static int ofdrm_probe(struct platform_device *pdev)
1352 {
1353 	struct ofdrm_device *odev;
1354 	struct drm_device *dev;
1355 	unsigned int color_mode;
1356 	int ret;
1357 
1358 	odev = ofdrm_device_create(&ofdrm_driver, pdev);
1359 	if (IS_ERR(odev))
1360 		return PTR_ERR(odev);
1361 	dev = &odev->dev;
1362 
1363 	ret = drm_dev_register(dev, 0);
1364 	if (ret)
1365 		return ret;
1366 
1367 	color_mode = drm_format_info_bpp(odev->format, 0);
1368 	if (color_mode == 16)
1369 		color_mode = odev->format->depth; // can be 15 or 16
1370 
1371 	drm_fbdev_generic_setup(dev, color_mode);
1372 
1373 	return 0;
1374 }
1375 
1376 static int ofdrm_remove(struct platform_device *pdev)
1377 {
1378 	struct drm_device *dev = platform_get_drvdata(pdev);
1379 
1380 	drm_dev_unplug(dev);
1381 
1382 	return 0;
1383 }
1384 
1385 static const struct of_device_id ofdrm_of_match_display[] = {
1386 	{ .compatible = "display", },
1387 	{ },
1388 };
1389 MODULE_DEVICE_TABLE(of, ofdrm_of_match_display);
1390 
1391 static struct platform_driver ofdrm_platform_driver = {
1392 	.driver = {
1393 		.name = "of-display",
1394 		.of_match_table = ofdrm_of_match_display,
1395 	},
1396 	.probe = ofdrm_probe,
1397 	.remove = ofdrm_remove,
1398 };
1399 
1400 module_platform_driver(ofdrm_platform_driver);
1401 
1402 MODULE_DESCRIPTION(DRIVER_DESC);
1403 MODULE_LICENSE("GPL");
1404