Messages in this thread Patch in this message | | | Date | Wed, 14 May 2014 10:20:43 +0200 | From | Alexander Holler <> | Subject | dt: deps: some tips about how to debug/evaluate this feature |
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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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