drivers/video/fbdev/ocfb.c

   1 /*
   2  * OpenCores VGA/LCD 2.0 core frame buffer driver
   3  *
   4  * Copyright (C) 2013 Stefan Kristiansson, stefan.kristiansson@saunalahti.fi
   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
  50 static char *mode_option;
  51
  52 static 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
  58 struct 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
  70 static 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
  87 static 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
  95 static 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
 103 static 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
 174 static 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
 211 static 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
 230 static 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
 288 static const struct fb_ops ocfb_ops = {
 289         .owner          = THIS_MODULE,
 290         FB_DEFAULT_IOMEM_OPS,
 291         .fb_setcolreg   = ocfb_setcolreg,
 292 };
 293
 294 static 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
 361 err_dealloc_cmap:
 362         fb_dealloc_cmap(&fbdev->info.cmap);
 363
 364 err_dma_free:
 365         dma_free_coherent(&pdev->dev, PAGE_ALIGN(fbsize), fbdev->fb_virt,
 366                           fbdev->fb_phys);
 367
 368         return ret;
 369 }
 370
 371 static 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
 386 static const struct of_device_id ocfb_match[] = {
 387         { .compatible = "opencores,ocfb", },
 388         {},
 389 };
 390 MODULE_DEVICE_TABLE(of, ocfb_match);
 391
 392 static struct platform_driver ocfb_driver = {
 393         .probe  = ocfb_probe,
 394         .remove_new = ocfb_remove,
 395         .driver = {
 396                 .name = "ocfb_fb",
 397                 .of_match_table = ocfb_match,
 398         }
 399 };
 400
 401 /*
 402  * Init and exit routines
 403  */
 404 static 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
 416 static void __exit ocfb_exit(void)
 417 {
 418         platform_driver_unregister(&ocfb_driver);
 419 }
 420
 421 module_init(ocfb_init);
 422 module_exit(ocfb_exit);
 423
 424 MODULE_AUTHOR("Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>");
 425 MODULE_DESCRIPTION("OpenCores VGA/LCD 2.0 frame buffer driver");
 426 MODULE_LICENSE("GPL v2");
 427 module_param(mode_option, charp, 0);
 428 MODULE_PARM_DESC(mode_option, "Video mode ('<xres>x<yres>[-<bpp>][@refresh]')");