dt: deps: some tips about how to debug/evaluate this feature

[Alexander Holler]

Hello,

to make it a bit more easier to evaluate or debug this new feature, here 
are some tips:

- To see the initialization order you can use dtc:

	CROSS_COMPILE=arm-linux-gnu- ARCH=arm make foo.dtb
	scripts/dtc/dtc -I dtb -t arch/arm/boot/dts/foo.dtb

- To see that order in dmesg, I've left a commented function
  in patch 2/9. Just enable of_init_print_order() in
  drivers/of/of_dependencies.c

- To see which drivers do call of_platform_populate() theirself
  (which is not necessary when using this new feature) uncomment the
  WARN_ON(np->dev_created); in drivers/of/platform.c (patch 2/9).

- To see which drivers are already "well done" or not, add a small
  debug line to of_init_register_platform_driver() in
  drivers/of/of_dependencies.c:

@@ -416,39 +416,41 @@ int of_init_register_platform_driver(struct 
platform_driver *drv)
 {
        BUG_ON(!is_recording);
        order.platform_drivers[order.count_drivers++] = drv;
+       pr_info("DEPS: recording of drv %s\n", drv->driver.name);
        return 0;
 }

  Now "well done" drivers linked to the kernel will be seen in dmesg as
  beeing recorded. This also shows most drivers which are not "well
  done", they will be started before the recording of drivers (except
  late ones).

- To see when "well done" drivers will be registered (in order) add
  something like that to drivers/of/of_dependencies.c:
@@ -445,8 +445,10 @@ void __init of_init_register_drivers(void)
                        if (of_driver_match_device(dev, &drv->driver)) {
                                if (!driver_find(drv->driver.name,
-                                   drv->driver.bus))
+                                   drv->driver.bus)) {
                                        platform_driver_register(drv);
+                                       pr_info("DEPS: driver %s 
registered\n", drv->name);
+                               }
                                if (dev->parent)
                                        device_lock(dev->parent);
                                rc = device_attach(dev);


Regards,

Alexander Holler
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/