kboot: Hide the notch

Signed-off-by: Hector Martin <[email protected]>

src/kboot.c

@@ -36,6 +36,42 @@ static size_t initrd_size = 0;
         goto err;                                                                                  \
     } while (0)
 
+void get_notchless_fb(u64 *fb_base, u64 *fb_height)
+{
+    *fb_base = cur_boot_args.video.base;
+    *fb_height = cur_boot_args.video.height;
+
+    int node = adt_path_offset(adt, "/product");
+
+    if (node < 0) {
+        printf("FDT: /product node not found\n");
+        return;
+    }
+
+    u32 val;
+
+    if (ADT_GETPROP(adt, node, "partially-occluded-display", &val) < 0 || !val) {
+        printf("FDT: No notch detected\n");
+        return;
+    }
+
+    u64 hfrac = cur_boot_args.video.height * 16 / cur_boot_args.video.width;
+    u64 new_height = cur_boot_args.video.width * hfrac / 16;
+
+    if (new_height == cur_boot_args.video.height) {
+        printf("FDT: Notch detected, but display aspect is already 16:%lu?\n", hfrac);
+        return;
+    }
+
+    u64 offset = cur_boot_args.video.height - new_height;
+
+    printf("display: Hiding notch, %lux%lu -> %lux%lu (+%lu, 16:%lu)\n", cur_boot_args.video.width,
+           cur_boot_args.video.height, cur_boot_args.video.width, new_height, offset, hfrac);
+
+    *fb_base += cur_boot_args.video.stride * offset;
+    *fb_height = new_height;
+}
+
 static int dt_set_chosen(void)
 {
 
@@ -69,8 +105,9 @@ static int dt_set_chosen(void)
         if (fb < 0)
             bail("FDT: /chosen node not found in devtree\n");
 
-        u64 fb_base = cur_boot_args.video.base;
-        u64 fb_size = cur_boot_args.video.stride * cur_boot_args.video.height;
+        u64 fb_base, fb_height;
+        get_notchless_fb(&fb_base, &fb_height);
+        u64 fb_size = cur_boot_args.video.stride * fb_height;
         u64 fbreg[2] = {cpu_to_fdt64(fb_base), cpu_to_fdt64(fb_size)};
         char fbname[32];
 
@@ -85,7 +122,7 @@ static int dt_set_chosen(void)
         if (fdt_setprop_u32(dt, fb, "width", cur_boot_args.video.width))
             bail("FDT: couldn't set framebuffer width\n");
 
-        if (fdt_setprop_u32(dt, fb, "height", cur_boot_args.video.height))
+        if (fdt_setprop_u32(dt, fb, "height", fb_height))
             bail("FDT: couldn't set framebuffer height\n");
 
         if (fdt_setprop_u32(dt, fb, "stride", cur_boot_args.video.stride))