1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for Aeroflex Gaisler SVGACTRL framebuffer device.
4 *
5 * 2011 (c) Aeroflex Gaisler AB
6 *
7 * Full documentation of the core can be found here:
8 * https://www.gaisler.com/products/grlib/grip.pdf
9 *
10 * Contributors: Kristoffer Glembo <kristoffer@gaisler.com>
11 */
12
13#include <linux/platform_device.h>
14#include <linux/dma-mapping.h>
15#include <linux/of.h>
16#include <linux/module.h>
17#include <linux/kernel.h>
18#include <linux/string.h>
19#include <linux/delay.h>
20#include <linux/errno.h>
21#include <linux/init.h>
22#include <linux/slab.h>
23#include <linux/tty.h>
24#include <linux/mm.h>
25#include <linux/fb.h>
26#include <linux/io.h>
27
28struct grvga_regs {
29	u32 status; 		/* 0x00 */
30	u32 video_length; 	/* 0x04 */
31	u32 front_porch;	/* 0x08 */
32	u32 sync_length;	/* 0x0C */
33	u32 line_length;	/* 0x10 */
34	u32 fb_pos;		/* 0x14 */
35	u32 clk_vector[4];	/* 0x18 */
36	u32 clut;	        /* 0x20 */
37};
38
39struct grvga_par {
40	struct grvga_regs *regs;
41	u32 color_palette[16];  /* 16 entry pseudo palette used by fbcon in true color mode */
42	int clk_sel;
43	int fb_alloced;         /* = 1 if framebuffer is allocated in main memory */
44};
45
46
47static const struct fb_videomode grvga_modedb[] = {
48    {
49	/* 640x480 @ 60 Hz */
50	NULL, 60, 640, 480, 40000, 48, 16, 39, 11, 96, 2,
51	0, FB_VMODE_NONINTERLACED
52    }, {
53	/* 800x600 @ 60 Hz */
54	NULL, 60, 800, 600, 25000, 88, 40, 23, 1, 128, 4,
55	0, FB_VMODE_NONINTERLACED
56    }, {
57	/* 800x600 @ 72 Hz */
58	NULL, 72, 800, 600, 20000, 64, 56, 23, 37, 120, 6,
59	0, FB_VMODE_NONINTERLACED
60    }, {
61	/* 1024x768 @ 60 Hz */
62	NULL, 60, 1024, 768, 15385, 160, 24, 29, 3, 136, 6,
63	0, FB_VMODE_NONINTERLACED
64    }
65 };
66
67static const struct fb_fix_screeninfo grvga_fix = {
68	.id =		"AG SVGACTRL",
69	.type =		FB_TYPE_PACKED_PIXELS,
70	.visual =       FB_VISUAL_PSEUDOCOLOR,
71	.xpanstep =	0,
72	.ypanstep =	1,
73	.ywrapstep =	0,
74	.accel =	FB_ACCEL_NONE,
75};
76
77static int grvga_check_var(struct fb_var_screeninfo *var,
78			   struct fb_info *info)
79{
80	struct grvga_par *par = info->par;
81	int i;
82
83	if (!var->xres)
84		var->xres = 1;
85	if (!var->yres)
86		var->yres = 1;
87	if (var->bits_per_pixel <= 8)
88		var->bits_per_pixel = 8;
89	else if (var->bits_per_pixel <= 16)
90		var->bits_per_pixel = 16;
91	else if (var->bits_per_pixel <= 24)
92		var->bits_per_pixel = 24;
93	else if (var->bits_per_pixel <= 32)
94		var->bits_per_pixel = 32;
95	else
96		return -EINVAL;
97
98	var->xres_virtual = var->xres;
99	var->yres_virtual = 2*var->yres;
100
101	if (info->fix.smem_len) {
102		if ((var->yres_virtual*var->xres_virtual*var->bits_per_pixel/8) > info->fix.smem_len)
103			return -ENOMEM;
104	}
105
106	/* Which clocks that are available can be read out in these registers */
107	for (i = 0; i <= 3 ; i++) {
108		if (var->pixclock == par->regs->clk_vector[i])
109			break;
110	}
111	if (i <= 3)
112		par->clk_sel = i;
113	else
114		return -EINVAL;
115
116	switch (info->var.bits_per_pixel) {
117	case 8:
118		var->red   = (struct fb_bitfield) {0, 8, 0};      /* offset, length, msb-right */
119		var->green = (struct fb_bitfield) {0, 8, 0};
120		var->blue  = (struct fb_bitfield) {0, 8, 0};
121		var->transp = (struct fb_bitfield) {0, 0, 0};
122		break;
123	case 16:
124		var->red   = (struct fb_bitfield) {11, 5, 0};
125		var->green = (struct fb_bitfield) {5, 6, 0};
126		var->blue  = (struct fb_bitfield) {0, 5, 0};
127		var->transp = (struct fb_bitfield) {0, 0, 0};
128		break;
129	case 24:
130	case 32:
131		var->red   = (struct fb_bitfield) {16, 8, 0};
132		var->green = (struct fb_bitfield) {8, 8, 0};
133		var->blue  = (struct fb_bitfield) {0, 8, 0};
134		var->transp = (struct fb_bitfield) {24, 8, 0};
135		break;
136	default:
137		return -EINVAL;
138	}
139
140	return 0;
141}
142
143static int grvga_set_par(struct fb_info *info)
144{
145
146	u32 func = 0;
147	struct grvga_par *par = info->par;
148
149	__raw_writel(((info->var.yres - 1) << 16) | (info->var.xres - 1),
150		     &par->regs->video_length);
151
152	__raw_writel((info->var.lower_margin << 16) | (info->var.right_margin),
153		     &par->regs->front_porch);
154
155	__raw_writel((info->var.vsync_len << 16) | (info->var.hsync_len),
156		     &par->regs->sync_length);
157
158	__raw_writel(((info->var.yres + info->var.lower_margin + info->var.upper_margin + info->var.vsync_len - 1) << 16) |
159		     (info->var.xres + info->var.right_margin + info->var.left_margin + info->var.hsync_len - 1),
160		     &par->regs->line_length);
161
162	switch (info->var.bits_per_pixel) {
163	case 8:
164		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
165		func = 1;
166		break;
167	case 16:
168		info->fix.visual = FB_VISUAL_TRUECOLOR;
169		func = 2;
170		break;
171	case 24:
172	case 32:
173		info->fix.visual = FB_VISUAL_TRUECOLOR;
174		func = 3;
175		break;
176	default:
177		return -EINVAL;
178	}
179
180	__raw_writel((par->clk_sel << 6) | (func << 4) | 1,
181		     &par->regs->status);
182
183	info->fix.line_length = (info->var.xres_virtual*info->var.bits_per_pixel)/8;
184	return 0;
185}
186
187static int grvga_setcolreg(unsigned regno, unsigned red, unsigned green, unsigned blue, unsigned transp, struct fb_info *info)
188{
189	struct grvga_par *par;
190	par = info->par;
191
192	if (regno >= 256)	/* Size of CLUT */
193		return -EINVAL;
194
195	if (info->var.grayscale) {
196		/* grayscale = 0.30*R + 0.59*G + 0.11*B */
197		red = green = blue = (red * 77 + green * 151 + blue * 28) >> 8;
198	}
199
200
201
202#define CNVT_TOHW(val, width) ((((val)<<(width))+0x7FFF-(val))>>16)
203
204	red    = CNVT_TOHW(red,   info->var.red.length);
205	green  = CNVT_TOHW(green, info->var.green.length);
206	blue   = CNVT_TOHW(blue,  info->var.blue.length);
207	transp = CNVT_TOHW(transp, info->var.transp.length);
208
209#undef CNVT_TOHW
210
211	/* In PSEUDOCOLOR we use the hardware CLUT */
212	if (info->fix.visual == FB_VISUAL_PSEUDOCOLOR)
213		__raw_writel((regno << 24) | (red << 16) | (green << 8) | blue,
214			     &par->regs->clut);
215
216	/* Truecolor uses the pseudo palette */
217	else if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
218		u32 v;
219		if (regno >= 16)
220			return -EINVAL;
221
222
223		v =     (red    << info->var.red.offset)   |
224			(green  << info->var.green.offset) |
225			(blue   << info->var.blue.offset)  |
226			(transp << info->var.transp.offset);
227
228		((u32 *) (info->pseudo_palette))[regno] = v;
229	}
230	return 0;
231}
232
233static int grvga_pan_display(struct fb_var_screeninfo *var,
234			     struct fb_info *info)
235{
236	struct grvga_par *par = info->par;
237	struct fb_fix_screeninfo *fix = &info->fix;
238	u32 base_addr;
239
240	if (var->xoffset != 0)
241		return -EINVAL;
242
243	base_addr = fix->smem_start + (var->yoffset * fix->line_length);
244	base_addr &= ~3UL;
245
246	/* Set framebuffer base address  */
247	__raw_writel(base_addr,
248		     &par->regs->fb_pos);
249
250	return 0;
251}
252
253static const struct fb_ops grvga_ops = {
254	.owner          = THIS_MODULE,
255	FB_DEFAULT_IOMEM_OPS,
256	.fb_check_var   = grvga_check_var,
257	.fb_set_par	= grvga_set_par,
258	.fb_setcolreg   = grvga_setcolreg,
259	.fb_pan_display = grvga_pan_display,
260};
261
262static int grvga_parse_custom(char *options,
263			      struct fb_var_screeninfo *screendata)
264{
265	char *this_opt;
266	int count = 0;
267	if (!options || !*options)
268		return -1;
269
270	while ((this_opt = strsep(&options, " ")) != NULL) {
271		if (!*this_opt)
272			continue;
273
274		switch (count) {
275		case 0:
276			screendata->pixclock = simple_strtoul(this_opt, NULL, 0);
277			count++;
278			break;
279		case 1:
280			screendata->xres = screendata->xres_virtual = simple_strtoul(this_opt, NULL, 0);
281			count++;
282			break;
283		case 2:
284			screendata->right_margin = simple_strtoul(this_opt, NULL, 0);
285			count++;
286			break;
287		case 3:
288			screendata->hsync_len = simple_strtoul(this_opt, NULL, 0);
289			count++;
290			break;
291		case 4:
292			screendata->left_margin = simple_strtoul(this_opt, NULL, 0);
293			count++;
294			break;
295		case 5:
296			screendata->yres = screendata->yres_virtual = simple_strtoul(this_opt, NULL, 0);
297			count++;
298			break;
299		case 6:
300			screendata->lower_margin = simple_strtoul(this_opt, NULL, 0);
301			count++;
302			break;
303		case 7:
304			screendata->vsync_len = simple_strtoul(this_opt, NULL, 0);
305			count++;
306			break;
307		case 8:
308			screendata->upper_margin = simple_strtoul(this_opt, NULL, 0);
309			count++;
310			break;
311		case 9:
312			screendata->bits_per_pixel = simple_strtoul(this_opt, NULL, 0);
313			count++;
314			break;
315		default:
316			return -1;
317		}
318	}
319	screendata->activate  = FB_ACTIVATE_NOW;
320	screendata->vmode     = FB_VMODE_NONINTERLACED;
321	return 0;
322}
323
324static int grvga_probe(struct platform_device *dev)
325{
326	struct fb_info *info;
327	int retval = -ENOMEM;
328	unsigned long virtual_start;
329	unsigned long grvga_fix_addr = 0;
330	unsigned long physical_start = 0;
331	unsigned long grvga_mem_size = 0;
332	struct grvga_par *par = NULL;
333	char *options = NULL, *mode_opt = NULL;
334
335	info = framebuffer_alloc(sizeof(struct grvga_par), &dev->dev);
336	if (!info)
337		return -ENOMEM;
338
339	/* Expecting: "grvga: modestring, [addr:<framebuffer physical address>], [size:<framebuffer size>]
340	 *
341	 * If modestring is custom:<custom mode string> we parse the string which then contains all videoparameters
342	 * If address is left out, we allocate memory,
343	 * if size is left out we only allocate enough to support the given mode.
344	 */
345	if (fb_get_options("grvga", &options)) {
346		retval = -ENODEV;
347		goto free_fb;
348	}
349
350	if (!options || !*options)
351		options =  "640x480-8@60";
352
353	while (1) {
354		char *this_opt = strsep(&options, ",");
355
356		if (!this_opt)
357			break;
358
359		if (!strncmp(this_opt, "custom", 6)) {
360			if (grvga_parse_custom(this_opt, &info->var) < 0) {
361				dev_err(&dev->dev, "Failed to parse custom mode (%s).\n", this_opt);
362				retval = -EINVAL;
363				goto free_fb;
364			}
365		} else if (!strncmp(this_opt, "addr", 4))
366			grvga_fix_addr = simple_strtoul(this_opt + 5, NULL, 16);
367		else if (!strncmp(this_opt, "size", 4))
368			grvga_mem_size = simple_strtoul(this_opt + 5, NULL, 0);
369		else
370			mode_opt = this_opt;
371	}
372
373	par = info->par;
374	info->fbops = &grvga_ops;
375	info->fix = grvga_fix;
376	info->pseudo_palette = par->color_palette;
377	info->flags = FBINFO_PARTIAL_PAN_OK | FBINFO_HWACCEL_YPAN;
378	info->fix.smem_len = grvga_mem_size;
379
380	if (!devm_request_mem_region(&dev->dev, dev->resource[0].start,
381		    resource_size(&dev->resource[0]), "grlib-svgactrl regs")) {
382		dev_err(&dev->dev, "registers already mapped\n");
383		retval = -EBUSY;
384		goto free_fb;
385	}
386
387	par->regs = of_ioremap(&dev->resource[0], 0,
388			       resource_size(&dev->resource[0]),
389			       "grlib-svgactrl regs");
390
391	if (!par->regs) {
392		dev_err(&dev->dev, "failed to map registers\n");
393		retval = -ENOMEM;
394		goto free_fb;
395	}
396
397	retval = fb_alloc_cmap(&info->cmap, 256, 0);
398	if (retval < 0) {
399		dev_err(&dev->dev, "failed to allocate mem with fb_alloc_cmap\n");
400		retval = -ENOMEM;
401		goto unmap_regs;
402	}
403
404	if (mode_opt) {
405		retval = fb_find_mode(&info->var, info, mode_opt,
406				      grvga_modedb, sizeof(grvga_modedb), &grvga_modedb[0], 8);
407		if (!retval || retval == 4) {
408			retval = -EINVAL;
409			goto dealloc_cmap;
410		}
411	}
412
413	if (!grvga_mem_size)
414		grvga_mem_size = info->var.xres_virtual * info->var.yres_virtual * info->var.bits_per_pixel/8;
415
416	if (grvga_fix_addr) {
417		/* Got framebuffer base address from argument list */
418
419		physical_start = grvga_fix_addr;
420
421		if (!devm_request_mem_region(&dev->dev, physical_start,
422					     grvga_mem_size, dev->name)) {
423			dev_err(&dev->dev, "failed to request memory region\n");
424			retval = -ENOMEM;
425			goto dealloc_cmap;
426		}
427
428		virtual_start = (unsigned long) ioremap(physical_start, grvga_mem_size);
429
430		if (!virtual_start) {
431			dev_err(&dev->dev, "error mapping framebuffer memory\n");
432			retval = -ENOMEM;
433			goto dealloc_cmap;
434		}
435	} else {	/* Allocate frambuffer memory */
436
437		unsigned long page;
438
439		virtual_start = (unsigned long) __get_free_pages(GFP_DMA,
440								 get_order(grvga_mem_size));
441		if (!virtual_start) {
442			dev_err(&dev->dev,
443				"unable to allocate framebuffer memory (%lu bytes)\n",
444				grvga_mem_size);
445			retval = -ENOMEM;
446			goto dealloc_cmap;
447		}
448
449		physical_start = dma_map_single(&dev->dev, (void *)virtual_start, grvga_mem_size, DMA_TO_DEVICE);
450
451		/* Set page reserved so that mmap will work. This is necessary
452		 * since we'll be remapping normal memory.
453		 */
454		for (page = virtual_start;
455		     page < PAGE_ALIGN(virtual_start + grvga_mem_size);
456		     page += PAGE_SIZE) {
457			SetPageReserved(virt_to_page(page));
458		}
459
460		par->fb_alloced = 1;
461	}
462
463	memset((unsigned long *) virtual_start, 0, grvga_mem_size);
464
465	info->screen_base = (char __iomem *) virtual_start;
466	info->fix.smem_start = physical_start;
467	info->fix.smem_len   = grvga_mem_size;
468
469	dev_set_drvdata(&dev->dev, info);
470
471	dev_info(&dev->dev,
472		 "Aeroflex Gaisler framebuffer device (fb%d), %dx%d-%d, using %luK of video memory @ %p\n",
473		 info->node, info->var.xres, info->var.yres, info->var.bits_per_pixel,
474		 grvga_mem_size >> 10, info->screen_base);
475
476	retval = register_framebuffer(info);
477	if (retval < 0) {
478		dev_err(&dev->dev, "failed to register framebuffer\n");
479		goto free_mem;
480	}
481
482	__raw_writel(physical_start, &par->regs->fb_pos);
483	__raw_writel(__raw_readl(&par->regs->status) | 1,  /* Enable framebuffer */
484		     &par->regs->status);
485
486	return 0;
487
488free_mem:
489	if (grvga_fix_addr)
490		iounmap((void *)virtual_start);
491	else
492		kfree((void *)virtual_start);
493dealloc_cmap:
494	fb_dealloc_cmap(&info->cmap);
495unmap_regs:
496	of_iounmap(&dev->resource[0], par->regs,
497		   resource_size(&dev->resource[0]));
498free_fb:
499	framebuffer_release(info);
500
501	return retval;
502}
503
504static void grvga_remove(struct platform_device *device)
505{
506	struct fb_info *info = dev_get_drvdata(&device->dev);
507	struct grvga_par *par;
508
509	if (info) {
510		par = info->par;
511		unregister_framebuffer(info);
512		fb_dealloc_cmap(&info->cmap);
513
514		of_iounmap(&device->resource[0], par->regs,
515			   resource_size(&device->resource[0]));
516
517		if (!par->fb_alloced)
518			iounmap(info->screen_base);
519		else
520			kfree((void *)info->screen_base);
521
522		framebuffer_release(info);
523	}
524}
525
526static struct of_device_id svgactrl_of_match[] = {
527	{
528		.name = "GAISLER_SVGACTRL",
529	},
530	{
531		.name = "01_063",
532	},
533	{},
534};
535MODULE_DEVICE_TABLE(of, svgactrl_of_match);
536
537static struct platform_driver grvga_driver = {
538	.driver = {
539		.name = "grlib-svgactrl",
540		.of_match_table = svgactrl_of_match,
541	},
542	.probe		= grvga_probe,
543	.remove_new	= grvga_remove,
544};
545
546module_platform_driver(grvga_driver);
547
548MODULE_LICENSE("GPL");
549MODULE_AUTHOR("Aeroflex Gaisler");
550MODULE_DESCRIPTION("Aeroflex Gaisler framebuffer device driver");
551