git.openwrt.org Git - openwrt/openwrt.git/blob

   1 From e8402a640a37c3a20523a9c95091a86511995b0c Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.com>
   3 Date: Mon, 9 Oct 2023 16:32:45 +0100
   4 Subject: [PATCH] fbdev: Allow client to request a particular /dev/fbN node
   5
   6 Add a flag custom_fb_num to denote that the client has
   7 requested a specific fbdev node number via node.
   8
   9 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
  10 ---
  11  drivers/video/fbdev/core/fbmem.c | 19 ++++++++++++++-----
  12  include/linux/fb.h               |  2 ++
  13  2 files changed, 16 insertions(+), 5 deletions(-)
  14
  15 --- a/drivers/video/fbdev/core/fbmem.c
  16 +++ b/drivers/video/fbdev/core/fbmem.c
  17 @@ -31,6 +31,7 @@ struct class *fb_class;
  18  DEFINE_MUTEX(registration_lock);
  19  struct fb_info *registered_fb[FB_MAX] __read_mostly;
  20  int num_registered_fb __read_mostly;
  21 +int min_dynamic_fb __read_mostly;
  22  #define for_each_registered_fb(i)              \
  23         for (i = 0; i < FB_MAX; i++)            \
  24                 if (!registered_fb[i]) {} else
  25 @@ -399,9 +400,12 @@ static int do_register_framebuffer(struc
  26         if (num_registered_fb == FB_MAX)
  27                 return -ENXIO;
  28
  29 -       for (i = 0 ; i < FB_MAX; i++)
  30 -               if (!registered_fb[i])
  31 -                       break;
  32 +       if (!fb_info->custom_fb_num || fb_info->node >= FB_MAX || registered_fb[fb_info->node]) {
  33 +               for (i = min_dynamic_fb ; i < FB_MAX; i++)
  34 +                       if (!registered_fb[i])
  35 +                               break;
  36 +               fb_info->node = i;
  37 +       }
  38
  39         if (!fb_info->modelist.prev || !fb_info->modelist.next)
  40                 INIT_LIST_HEAD(&fb_info->modelist);
  41 @@ -411,7 +415,6 @@ static int do_register_framebuffer(struc
  42         if (err < 0)
  43                 return err;
  44
  45 -       fb_info->node = i;
  46         refcount_set(&fb_info->count, 1);
  47         mutex_init(&fb_info->lock);
  48         mutex_init(&fb_info->mm_lock);
  49 @@ -442,7 +445,7 @@ static int do_register_framebuffer(struc
  50                 pm_vt_switch_required(fb_info->device, true);
  51
  52         num_registered_fb++;
  53 -       registered_fb[i] = fb_info;
  54 +       registered_fb[fb_info->node] = fb_info;
  55
  56  #ifdef CONFIG_GUMSTIX_AM200EPD
  57         {
  58 @@ -503,6 +506,12 @@ static void do_unregister_framebuffer(st
  59         put_fb_info(fb_info);
  60  }
  61
  62 +void fb_set_lowest_dynamic_fb(int min_fb_dev)
  63 +{
  64 +       min_dynamic_fb = min_fb_dev;
  65 +}
  66 +EXPORT_SYMBOL(fb_set_lowest_dynamic_fb);
  67 +
  68  /**
  69   *     register_framebuffer - registers a frame buffer device
  70   *     @fb_info: frame buffer info structure
  71 --- a/include/linux/fb.h
  72 +++ b/include/linux/fb.h
  73 @@ -511,6 +511,7 @@ struct fb_info {
  74
  75         bool skip_vt_switch; /* no VT switch on suspend/resume required */
  76         bool skip_panic; /* Do not write to the fb after a panic */
  77 +       bool custom_fb_num; /* Use value in node as the preferred node number */
  78  };
  79
  80  /* This will go away
  81 @@ -600,6 +601,7 @@ extern ssize_t fb_sys_write(struct fb_in
  82         .fb_imageblit   = sys_imageblit
  83
  84  /* fbmem.c */
  85 +extern void fb_set_lowest_dynamic_fb(int min_fb_dev);
  86  extern int register_framebuffer(struct fb_info *fb_info);
  87  extern void unregister_framebuffer(struct fb_info *fb_info);
  88  extern int devm_register_framebuffer(struct device *dev, struct fb_info *fb_info);