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1/*
2 * OpenCores VGA/LCD 2.0 core frame buffer driver
3 *
4 * Copyright (C) 2013 Stefan Kristiansson, [email protected]
5 *
6 * This file is licensed under the terms of the GNU General Public License
7 * version 2. This program is licensed "as is" without any warranty of any
8 * kind, whether express or implied.
9 */
10
11#include <linux/delay.h>
12#include <linux/dma-mapping.h>
13#include <linux/errno.h>
14#include <linux/fb.h>
15#include <linux/init.h>
16#include <linux/io.h>
17#include <linux/kernel.h>
18#include <linux/mm.h>
19#include <linux/module.h>
20#include <linux/of.h>
21#include <linux/platform_device.h>
22#include <linux/string.h>
23#include <linux/slab.h>
24
25/* OCFB register defines */
26#define OCFB_CTRL 0x000
27#define OCFB_STAT 0x004
28#define OCFB_HTIM 0x008
29#define OCFB_VTIM 0x00c
30#define OCFB_HVLEN 0x010
31#define OCFB_VBARA 0x014
32#define OCFB_PALETTE 0x800
33
34#define OCFB_CTRL_VEN 0x00000001 /* Video Enable */
35#define OCFB_CTRL_HIE 0x00000002 /* HSync Interrupt Enable */
36#define OCFB_CTRL_PC 0x00000800 /* 8-bit Pseudo Color Enable*/
37#define OCFB_CTRL_CD8 0x00000000 /* Color Depth 8 */
38#define OCFB_CTRL_CD16 0x00000200 /* Color Depth 16 */
39#define OCFB_CTRL_CD24 0x00000400 /* Color Depth 24 */
40#define OCFB_CTRL_CD32 0x00000600 /* Color Depth 32 */
41#define OCFB_CTRL_VBL1 0x00000000 /* Burst Length 1 */
42#define OCFB_CTRL_VBL2 0x00000080 /* Burst Length 2 */
43#define OCFB_CTRL_VBL4 0x00000100 /* Burst Length 4 */
44#define OCFB_CTRL_VBL8 0x00000180 /* Burst Length 8 */
45
46#define PALETTE_SIZE 256
47
48#define OCFB_NAME "OC VGA/LCD"
49
50static char *mode_option;
51
52static const struct fb_videomode default_mode = {
53 /* 640x480 @ 60 Hz, 31.5 kHz hsync */
54 NULL, 60, 640, 480, 39721, 40, 24, 32, 11, 96, 2,
55 0, FB_VMODE_NONINTERLACED
56};
57
58struct ocfb_dev {
59 struct fb_info info;
60 void __iomem *regs;
61 /* flag indicating whether the regs are little endian accessed */
62 int little_endian;
63 /* Physical and virtual addresses of framebuffer */
64 dma_addr_t fb_phys;
65 void __iomem *fb_virt;
66 u32 pseudo_palette[PALETTE_SIZE];
67};
68
69#ifndef MODULE
70static int __init ocfb_setup(char *options)
71{
72 char *curr_opt;
73
74 if (!options || !*options)
75 return 0;
76
77 while ((curr_opt = strsep(&options, ",")) != NULL) {
78 if (!*curr_opt)
79 continue;
80 mode_option = curr_opt;
81 }
82
83 return 0;
84}
85#endif
86
87static inline u32 ocfb_readreg(struct ocfb_dev *fbdev, loff_t offset)
88{
89 if (fbdev->little_endian)
90 return ioread32(fbdev->regs + offset);
91 else
92 return ioread32be(fbdev->regs + offset);
93}
94
95static void ocfb_writereg(struct ocfb_dev *fbdev, loff_t offset, u32 data)
96{
97 if (fbdev->little_endian)
98 iowrite32(data, fbdev->regs + offset);
99 else
100 iowrite32be(data, fbdev->regs + offset);
101}
102
103static int ocfb_setupfb(struct ocfb_dev *fbdev)
104{
105 unsigned long bpp_config;
106 struct fb_var_screeninfo *var = &fbdev->info.var;
107 struct device *dev = fbdev->info.device;
108 u32 hlen;
109 u32 vlen;
110
111 /* Disable display */
112 ocfb_writereg(fbdev, OCFB_CTRL, 0);
113
114 /* Register framebuffer address */
115 fbdev->little_endian = 0;
116 ocfb_writereg(fbdev, OCFB_VBARA, fbdev->fb_phys);
117
118 /* Detect endianess */
119 if (ocfb_readreg(fbdev, OCFB_VBARA) != fbdev->fb_phys) {
120 fbdev->little_endian = 1;
121 ocfb_writereg(fbdev, OCFB_VBARA, fbdev->fb_phys);
122 }
123
124 /* Horizontal timings */
125 ocfb_writereg(fbdev, OCFB_HTIM, (var->hsync_len - 1) << 24 |
126 (var->left_margin - 1) << 16 | (var->xres - 1));
127
128 /* Vertical timings */
129 ocfb_writereg(fbdev, OCFB_VTIM, (var->vsync_len - 1) << 24 |
130 (var->upper_margin - 1) << 16 | (var->yres - 1));
131
132 /* Total length of frame */
133 hlen = var->left_margin + var->right_margin + var->hsync_len +
134 var->xres;
135
136 vlen = var->upper_margin + var->lower_margin + var->vsync_len +
137 var->yres;
138
139 ocfb_writereg(fbdev, OCFB_HVLEN, (hlen - 1) << 16 | (vlen - 1));
140
141 bpp_config = OCFB_CTRL_CD8;
142 switch (var->bits_per_pixel) {
143 case 8:
144 if (!var->grayscale)
145 bpp_config |= OCFB_CTRL_PC; /* enable palette */
146 break;
147
148 case 16:
149 bpp_config |= OCFB_CTRL_CD16;
150 break;
151
152 case 24:
153 bpp_config |= OCFB_CTRL_CD24;
154 break;
155
156 case 32:
157 bpp_config |= OCFB_CTRL_CD32;
158 break;
159
160 default:
161 dev_err(dev, "no bpp specified\n");
162 break;
163 }
164
165 /* maximum (8) VBL (video memory burst length) */
166 bpp_config |= OCFB_CTRL_VBL8;
167
168 /* Enable output */
169 ocfb_writereg(fbdev, OCFB_CTRL, (OCFB_CTRL_VEN | bpp_config));
170
171 return 0;
172}
173
174static int ocfb_setcolreg(unsigned regno, unsigned red, unsigned green,
175 unsigned blue, unsigned transp,
176 struct fb_info *info)
177{
178 struct ocfb_dev *fbdev = (struct ocfb_dev *)info->par;
179 u32 color;
180
181 if (regno >= info->cmap.len) {
182 dev_err(info->device, "regno >= cmap.len\n");
183 return 1;
184 }
185
186 if (info->var.grayscale) {
187 /* grayscale = 0.30*R + 0.59*G + 0.11*B */
188 red = green = blue = (red * 77 + green * 151 + blue * 28) >> 8;
189 }
190
191 red >>= (16 - info->var.red.length);
192 green >>= (16 - info->var.green.length);
193 blue >>= (16 - info->var.blue.length);
194 transp >>= (16 - info->var.transp.length);
195
196 if (info->var.bits_per_pixel == 8 && !info->var.grayscale) {
197 regno <<= 2;
198 color = (red << 16) | (green << 8) | blue;
199 ocfb_writereg(fbdev, OCFB_PALETTE + regno, color);
200 } else {
201 ((u32 *)(info->pseudo_palette))[regno] =
202 (red << info->var.red.offset) |
203 (green << info->var.green.offset) |
204 (blue << info->var.blue.offset) |
205 (transp << info->var.transp.offset);
206 }
207
208 return 0;
209}
210
211static int ocfb_init_fix(struct ocfb_dev *fbdev)
212{
213 struct fb_var_screeninfo *var = &fbdev->info.var;
214 struct fb_fix_screeninfo *fix = &fbdev->info.fix;
215
216 strcpy(fix->id, OCFB_NAME);
217
218 fix->line_length = var->xres * var->bits_per_pixel/8;
219 fix->smem_len = fix->line_length * var->yres;
220 fix->type = FB_TYPE_PACKED_PIXELS;
221
222 if (var->bits_per_pixel == 8 && !var->grayscale)
223 fix->visual = FB_VISUAL_PSEUDOCOLOR;
224 else
225 fix->visual = FB_VISUAL_TRUECOLOR;
226
227 return 0;
228}
229
230static int ocfb_init_var(struct ocfb_dev *fbdev)
231{
232 struct fb_var_screeninfo *var = &fbdev->info.var;
233
234 var->accel_flags = FB_ACCEL_NONE;
235 var->activate = FB_ACTIVATE_NOW;
236 var->xres_virtual = var->xres;
237 var->yres_virtual = var->yres;
238
239 switch (var->bits_per_pixel) {
240 case 8:
241 var->transp.offset = 0;
242 var->transp.length = 0;
243 var->red.offset = 0;
244 var->red.length = 8;
245 var->green.offset = 0;
246 var->green.length = 8;
247 var->blue.offset = 0;
248 var->blue.length = 8;
249 break;
250
251 case 16:
252 var->transp.offset = 0;
253 var->transp.length = 0;
254 var->red.offset = 11;
255 var->red.length = 5;
256 var->green.offset = 5;
257 var->green.length = 6;
258 var->blue.offset = 0;
259 var->blue.length = 5;
260 break;
261
262 case 24:
263 var->transp.offset = 0;
264 var->transp.length = 0;
265 var->red.offset = 16;
266 var->red.length = 8;
267 var->green.offset = 8;
268 var->green.length = 8;
269 var->blue.offset = 0;
270 var->blue.length = 8;
271 break;
272
273 case 32:
274 var->transp.offset = 24;
275 var->transp.length = 8;
276 var->red.offset = 16;
277 var->red.length = 8;
278 var->green.offset = 8;
279 var->green.length = 8;
280 var->blue.offset = 0;
281 var->blue.length = 8;
282 break;
283 }
284
285 return 0;
286}
287
288static const struct fb_ops ocfb_ops = {
289 .owner = THIS_MODULE,
290 FB_DEFAULT_IOMEM_OPS,
291 .fb_setcolreg = ocfb_setcolreg,
292};
293
294static int ocfb_probe(struct platform_device *pdev)
295{
296 int ret = 0;
297 struct ocfb_dev *fbdev;
298 int fbsize;
299
300 fbdev = devm_kzalloc(&pdev->dev, sizeof(*fbdev), GFP_KERNEL);
301 if (!fbdev)
302 return -ENOMEM;
303
304 platform_set_drvdata(pdev, fbdev);
305
306 fbdev->info.fbops = &ocfb_ops;
307 fbdev->info.device = &pdev->dev;
308 fbdev->info.par = fbdev;
309
310 /* Video mode setup */
311 if (!fb_find_mode(&fbdev->info.var, &fbdev->info, mode_option,
312 NULL, 0, &default_mode, 16)) {
313 dev_err(&pdev->dev, "No valid video modes found\n");
314 return -EINVAL;
315 }
316 ocfb_init_var(fbdev);
317 ocfb_init_fix(fbdev);
318
319 fbdev->regs = devm_platform_ioremap_resource(pdev, 0);
320 if (IS_ERR(fbdev->regs))
321 return PTR_ERR(fbdev->regs);
322
323 /* Allocate framebuffer memory */
324 fbsize = fbdev->info.fix.smem_len;
325 fbdev->fb_virt = dma_alloc_coherent(&pdev->dev, PAGE_ALIGN(fbsize),
326 &fbdev->fb_phys, GFP_KERNEL);
327 if (!fbdev->fb_virt) {
328 dev_err(&pdev->dev,
329 "Frame buffer memory allocation failed\n");
330 return -ENOMEM;
331 }
332 fbdev->info.fix.smem_start = fbdev->fb_phys;
333 fbdev->info.screen_base = fbdev->fb_virt;
334 fbdev->info.pseudo_palette = fbdev->pseudo_palette;
335
336 /* Clear framebuffer */
337 memset_io(fbdev->fb_virt, 0, fbsize);
338
339 /* Setup and enable the framebuffer */
340 ocfb_setupfb(fbdev);
341
342 if (fbdev->little_endian)
343 fbdev->info.flags |= FBINFO_FOREIGN_ENDIAN;
344
345 /* Allocate color map */
346 ret = fb_alloc_cmap(&fbdev->info.cmap, PALETTE_SIZE, 0);
347 if (ret) {
348 dev_err(&pdev->dev, "Color map allocation failed\n");
349 goto err_dma_free;
350 }
351
352 /* Register framebuffer */
353 ret = register_framebuffer(&fbdev->info);
354 if (ret) {
355 dev_err(&pdev->dev, "Framebuffer registration failed\n");
356 goto err_dealloc_cmap;
357 }
358
359 return 0;
360
361err_dealloc_cmap:
362 fb_dealloc_cmap(&fbdev->info.cmap);
363
364err_dma_free:
365 dma_free_coherent(&pdev->dev, PAGE_ALIGN(fbsize), fbdev->fb_virt,
366 fbdev->fb_phys);
367
368 return ret;
369}
370
371static void ocfb_remove(struct platform_device *pdev)
372{
373 struct ocfb_dev *fbdev = platform_get_drvdata(pdev);
374
375 unregister_framebuffer(&fbdev->info);
376 fb_dealloc_cmap(&fbdev->info.cmap);
377 dma_free_coherent(&pdev->dev, PAGE_ALIGN(fbdev->info.fix.smem_len),
378 fbdev->fb_virt, fbdev->fb_phys);
379
380 /* Disable display */
381 ocfb_writereg(fbdev, OCFB_CTRL, 0);
382
383 platform_set_drvdata(pdev, NULL);
384}
385
386static const struct of_device_id ocfb_match[] = {
387 { .compatible = "opencores,ocfb", },
388 {},
389};
390MODULE_DEVICE_TABLE(of, ocfb_match);
391
392static struct platform_driver ocfb_driver = {
393 .probe = ocfb_probe,
394 .remove = ocfb_remove,
395 .driver = {
396 .name = "ocfb_fb",
397 .of_match_table = ocfb_match,
398 }
399};
400
401/*
402 * Init and exit routines
403 */
404static int __init ocfb_init(void)
405{
406#ifndef MODULE
407 char *option = NULL;
408
409 if (fb_get_options("ocfb", &option))
410 return -ENODEV;
411 ocfb_setup(option);
412#endif
413 return platform_driver_register(&ocfb_driver);
414}
415
416static void __exit ocfb_exit(void)
417{
418 platform_driver_unregister(&ocfb_driver);
419}
420
421module_init(ocfb_init);
422module_exit(ocfb_exit);
423
424MODULE_AUTHOR("Stefan Kristiansson <[email protected]>");
425MODULE_DESCRIPTION("OpenCores VGA/LCD 2.0 frame buffer driver");
426MODULE_LICENSE("GPL v2");
427module_param(mode_option, charp, 0);
428MODULE_PARM_DESC(mode_option, "Video mode ('<xres>x<yres>[-<bpp>][@refresh]')");