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       1                 :            : // SPDX-License-Identifier: GPL-2.0-or-later
       2                 :            : /*
       3                 :            :  * Generic System Framebuffers on x86
       4                 :            :  * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
       5                 :            :  */
       6                 :            : 
       7                 :            : /*
       8                 :            :  * Simple-Framebuffer support for x86 systems
       9                 :            :  * Create a platform-device for any available boot framebuffer. The
      10                 :            :  * simple-framebuffer platform device is already available on DT systems, so
      11                 :            :  * this module parses the global "screen_info" object and creates a suitable
      12                 :            :  * platform device compatible with the "simple-framebuffer" DT object. If
      13                 :            :  * the framebuffer is incompatible, we instead create a legacy
      14                 :            :  * "vesa-framebuffer", "efi-framebuffer" or "platform-framebuffer" device and
      15                 :            :  * pass the screen_info as platform_data. This allows legacy drivers
      16                 :            :  * to pick these devices up without messing with simple-framebuffer drivers.
      17                 :            :  * The global "screen_info" is still valid at all times.
      18                 :            :  *
      19                 :            :  * If CONFIG_X86_SYSFB is not selected, we never register "simple-framebuffer"
      20                 :            :  * platform devices, but only use legacy framebuffer devices for
      21                 :            :  * backwards compatibility.
      22                 :            :  *
      23                 :            :  * TODO: We set the dev_id field of all platform-devices to 0. This allows
      24                 :            :  * other x86 OF/DT parsers to create such devices, too. However, they must
      25                 :            :  * start at offset 1 for this to work.
      26                 :            :  */
      27                 :            : 
      28                 :            : #include <linux/err.h>
      29                 :            : #include <linux/init.h>
      30                 :            : #include <linux/kernel.h>
      31                 :            : #include <linux/mm.h>
      32                 :            : #include <linux/platform_data/simplefb.h>
      33                 :            : #include <linux/platform_device.h>
      34                 :            : #include <linux/screen_info.h>
      35                 :            : #include <asm/sysfb.h>
      36                 :            : 
      37                 :         78 : static __init int sysfb_init(void)
      38                 :            : {
      39                 :         78 :         struct screen_info *si = &screen_info;
      40                 :         78 :         struct simplefb_platform_data mode;
      41                 :         78 :         struct platform_device *pd;
      42                 :         78 :         const char *name;
      43                 :         78 :         bool compatible;
      44                 :         78 :         int ret;
      45                 :            : 
      46                 :         78 :         sysfb_apply_efi_quirks();
      47                 :            : 
      48                 :            :         /* try to create a simple-framebuffer device */
      49         [ +  - ]:         78 :         compatible = parse_mode(si, &mode);
      50                 :         78 :         if (compatible) {
      51                 :            :                 ret = create_simplefb(si, &mode);
      52                 :            :                 if (!ret)
      53                 :            :                         return 0;
      54                 :            :         }
      55                 :            : 
      56                 :            :         /* if the FB is incompatible, create a legacy framebuffer device */
      57         [ +  - ]:         78 :         if (si->orig_video_isVGA == VIDEO_TYPE_EFI)
      58                 :            :                 name = "efi-framebuffer";
      59         [ +  - ]:         78 :         else if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
      60                 :            :                 name = "vesa-framebuffer";
      61                 :            :         else
      62                 :         78 :                 name = "platform-framebuffer";
      63                 :            : 
      64                 :         78 :         pd = platform_device_register_resndata(NULL, name, 0,
      65                 :            :                                                NULL, 0, si, sizeof(*si));
      66         [ -  + ]:         78 :         return PTR_ERR_OR_ZERO(pd);
      67                 :            : }
      68                 :            : 
      69                 :            : /* must execute after PCI subsystem for EFI quirks */
      70                 :            : device_initcall(sysfb_init);