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 <[email protected]>
   8  * Copyright 2017 Google Inc.
   9  * Copyright 2017 Samuel Holland <[email protected]>
  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         if (!fb->physical_address)
  40                 return -ENODEV;
  41
  42         for (i = 0; i < ARRAY_SIZE(formats); ++i) {
  43                 if (fb->bits_per_pixel     == formats[i].bits_per_pixel &&
  44                     fb->red_mask_pos       == formats[i].red.offset &&
  45                     fb->red_mask_size      == formats[i].red.length &&
  46                     fb->green_mask_pos     == formats[i].green.offset &&
  47                     fb->green_mask_size    == formats[i].green.length &&
  48                     fb->blue_mask_pos      == formats[i].blue.offset &&
  49                     fb->blue_mask_size     == formats[i].blue.length)
  50                         pdata.format = formats[i].name;
  51         }
  52         if (!pdata.format)
  53                 return -ENODEV;
  54
  55         memset(&res, 0, sizeof(res));
  56         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  57         res.name = "Coreboot Framebuffer";
  58         res.start = fb->physical_address;
  59         length = PAGE_ALIGN(fb->y_resolution * fb->bytes_per_line);
  60         res.end = res.start + length - 1;
  61         if (res.end <= res.start)
  62                 return -EINVAL;
  63
  64         pdev = platform_device_register_resndata(&dev->dev,
  65                                                  "simple-framebuffer", 0,
  66                                                  &res, 1, &pdata,
  67                                                  sizeof(pdata));
  68         if (IS_ERR(pdev))
  69                 pr_warn("coreboot: could not register framebuffer\n");
  70         else
  71                 dev_set_drvdata(&dev->dev, pdev);
  72
  73         return PTR_ERR_OR_ZERO(pdev);
  74 }
  75
  76 static void framebuffer_remove(struct coreboot_device *dev)
  77 {
  78         struct platform_device *pdev = dev_get_drvdata(&dev->dev);
  79
  80         platform_device_unregister(pdev);
  81 }
  82
  83 static const struct coreboot_device_id framebuffer_ids[] = {
  84         { .tag = CB_TAG_FRAMEBUFFER },
  85         { /* sentinel */ }
  86 };
  87 MODULE_DEVICE_TABLE(coreboot, framebuffer_ids);
  88
  89 static struct coreboot_driver framebuffer_driver = {
  90         .probe = framebuffer_probe,
  91         .remove = framebuffer_remove,
  92         .drv = {
  93                 .name = "framebuffer",
  94         },
  95         .id_table = framebuffer_ids,
  96 };
  97 module_coreboot_driver(framebuffer_driver);
  98
  99 MODULE_AUTHOR("Samuel Holland <[email protected]>");
 100 MODULE_DESCRIPTION("Memory based framebuffer accessed through coreboot table");
 101 MODULE_LICENSE("GPL");