drivers/firmware/google/framebuffer-coreboot.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * framebuffer-coreboot.c
   4  *
   5  * Memory based framebuffer accessed through coreboot table.
   6  *
   7  * Copyright 2012-2013 David Herrmann <dh.herrmann@gmail.com>
   8  * Copyright 2017 Google Inc.
   9  * Copyright 2017 Samuel Holland <samuel@sholland.org>
  10  */
  11
  12 #include <linux/device.h>
  13 #include <linux/kernel.h>
  14 #include <linux/mm.h>
  15 #include <linux/module.h>
  16 #include <linux/platform_data/simplefb.h>
  17 #include <linux/platform_device.h>
  18
  19 #include "coreboot_table.h"
  20
  21 #define CB_TAG_FRAMEBUFFER 0x12
  22
  23 static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
  24
  25 static int framebuffer_probe(struct coreboot_device *dev)
  26 {
  27         int i;
  28         u32 length;
  29         struct lb_framebuffer *fb = &dev->framebuffer;
  30         struct platform_device *pdev;
  31         struct resource res;
  32         struct simplefb_platform_data pdata = {
  33                 .width = fb->x_resolution,
  34                 .height = fb->y_resolution,
  35                 .stride = fb->bytes_per_line,
  36                 .format = NULL,
  37         };
  38
  39         for (i = 0; i < ARRAY_SIZE(formats); ++i) {
  40                 if (fb->bits_per_pixel     == formats[i].bits_per_pixel &&
  41                     fb->red_mask_pos       == formats[i].red.offset &&
  42                     fb->red_mask_size      == formats[i].red.length &&
  43                     fb->green_mask_pos     == formats[i].green.offset &&
  44                     fb->green_mask_size    == formats[i].green.length &&
  45                     fb->blue_mask_pos      == formats[i].blue.offset &&
  46                     fb->blue_mask_size     == formats[i].blue.length &&
  47                     fb->reserved_mask_pos  == formats[i].transp.offset &&
  48                     fb->reserved_mask_size == formats[i].transp.length)
  49                         pdata.format = formats[i].name;
  50         }
  51         if (!pdata.format)
  52                 return -ENODEV;
  53
  54         memset(&res, 0, sizeof(res));
  55         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  56         res.name = "Coreboot Framebuffer";
  57         res.start = fb->physical_address;
  58         length = PAGE_ALIGN(fb->y_resolution * fb->bytes_per_line);
  59         res.end = res.start + length - 1;
  60         if (res.end <= res.start)
  61                 return -EINVAL;
  62
  63         pdev = platform_device_register_resndata(&dev->dev,
  64                                                  "simple-framebuffer", 0,
  65                                                  &res, 1, &pdata,
  66                                                  sizeof(pdata));
  67         if (IS_ERR(pdev))
  68                 pr_warn("coreboot: could not register framebuffer\n");
  69         else
  70                 dev_set_drvdata(&dev->dev, pdev);
  71
  72         return PTR_ERR_OR_ZERO(pdev);
  73 }
  74
  75 static int framebuffer_remove(struct coreboot_device *dev)
  76 {
  77         struct platform_device *pdev = dev_get_drvdata(&dev->dev);
  78
  79         platform_device_unregister(pdev);
  80
  81         return 0;
  82 }
  83
  84 static struct coreboot_driver framebuffer_driver = {
  85         .probe = framebuffer_probe,
  86         .remove = framebuffer_remove,
  87         .drv = {
  88                 .name = "framebuffer",
  89         },
  90         .tag = CB_TAG_FRAMEBUFFER,
  91 };
  92
  93 static int __init coreboot_framebuffer_init(void)
  94 {
  95         return coreboot_driver_register(&framebuffer_driver);
  96 }
  97
  98 static void coreboot_framebuffer_exit(void)
  99 {
 100         coreboot_driver_unregister(&framebuffer_driver);
 101 }
 102
 103 module_init(coreboot_framebuffer_init);
 104 module_exit(coreboot_framebuffer_exit);
 105
 106 MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
 107 MODULE_LICENSE("GPL");