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
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