target/linux/bcm27xx/patches-6.1/950-1035-fbdev-Allow-client-to-request-a-particular-dev-fbN-n.patch

   1 From 0c7fb448e0e0e47c2b3be64e438208682c6a5e61 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 | 24 +++++++++++++++++-------
  12  include/linux/fb.h               |  2 ++
  13  2 files changed, 19 insertions(+), 7 deletions(-)
  14
  15 --- a/drivers/video/fbdev/core/fbmem.c
  16 +++ b/drivers/video/fbdev/core/fbmem.c
  17 @@ -52,6 +52,7 @@ static DEFINE_MUTEX(registration_lock);
  18
  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 @@ -1579,19 +1580,22 @@ static int do_register_framebuffer(struc
  26                 return -ENXIO;
  27
  28         num_registered_fb++;
  29 -       for (i = 0 ; i < FB_MAX; i++)
  30 -               if (!registered_fb[i])
  31 -                       break;
  32 -       fb_info->node = i;
  33 +       if (!fb_info->custom_fb_num || fb_info->node >= FB_MAX || registered_fb[fb_info->node]) {
  34 +               for (i = min_dynamic_fb ; i < FB_MAX; i++)
  35 +                       if (!registered_fb[i])
  36 +                               break;
  37 +               fb_info->node = i;
  38 +       }
  39         refcount_set(&fb_info->count, 1);
  40         mutex_init(&fb_info->lock);
  41         mutex_init(&fb_info->mm_lock);
  42
  43         fb_info->dev = device_create(fb_class, fb_info->device,
  44 -                                    MKDEV(FB_MAJOR, i), NULL, "fb%d", i);
  45 +                                    MKDEV(FB_MAJOR, fb_info->node), NULL, "fb%d", fb_info->node);
  46         if (IS_ERR(fb_info->dev)) {
  47                 /* Not fatal */
  48 -               printk(KERN_WARNING "Unable to create device for framebuffer %d; errno = %ld\n", i, PTR_ERR(fb_info->dev));
  49 +               printk(KERN_WARNING "Unable to create device for framebuffer %d; errno = %ld\n",
  50 +                      fb_info->node, PTR_ERR(fb_info->dev));
  51                 fb_info->dev = NULL;
  52         } else
  53                 fb_init_device(fb_info);
  54 @@ -1624,7 +1628,7 @@ static int do_register_framebuffer(struc
  55
  56         fb_var_to_videomode(&mode, &fb_info->var);
  57         fb_add_videomode(&mode, &fb_info->modelist);
  58 -       registered_fb[i] = fb_info;
  59 +       registered_fb[fb_info->node] = fb_info;
  60
  61  #ifdef CONFIG_GUMSTIX_AM200EPD
  62         {
  63 @@ -1719,6 +1723,12 @@ static int fb_aperture_acquire_for_platf
  64         return ret;
  65  }
  66
  67 +void fb_set_lowest_dynamic_fb(int min_fb_dev)
  68 +{
  69 +       min_dynamic_fb = min_fb_dev;
  70 +}
  71 +EXPORT_SYMBOL(fb_set_lowest_dynamic_fb);
  72 +
  73  /**
  74   *     register_framebuffer - registers a frame buffer device
  75   *     @fb_info: frame buffer info structure
  76 --- a/include/linux/fb.h
  77 +++ b/include/linux/fb.h
  78 @@ -512,6 +512,7 @@ struct fb_info {
  79         } *apertures;
  80
  81         bool skip_vt_switch; /* no VT switch on suspend/resume required */
  82 +       bool custom_fb_num; /* Use value in node as the preferred node number */
  83  };
  84
  85  static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
  86 @@ -614,6 +615,7 @@ extern ssize_t fb_sys_write(struct fb_in
  87                             size_t count, loff_t *ppos);
  88
  89  /* drivers/video/fbmem.c */
  90 +extern void fb_set_lowest_dynamic_fb(int min_fb_dev);
  91  extern int register_framebuffer(struct fb_info *fb_info);
  92  extern void unregister_framebuffer(struct fb_info *fb_info);
  93  extern int fb_prepare_logo(struct fb_info *fb_info, int rotate);