Am 27.05.2014 22:02, schrieb Grant Likely:

On Mon, 19 May 2014 14:35:49 +0200, Alexander Holler [off-list ref] wrote:

quoted

What's still questionable about the patches for dtc is if dependencies 
to devices and not just drivers should be included in the new property 
dependencies too. My current assumption is that all devices belonging to 
one and the same driver don't have dependencies between each other. In 
other words the order in which devices will be attached to one and the 
same driver isn't important. If that assumption is correct it would be 
possible to just attach all devices belonging to a driver after the 
driver was loaded (also I haven't that done in my patches).

There aren't really any guarantees here. It is perfectly valid to have
two of the same device depending on the other, or even a device with a
different driver between the two.

There's always going to be corner cases on the dependency chain. The
question is whether or not it is worth trying to solve every concievable
order, or if a partway solution is good enough.

Solving dependencies always happens automatically, with or without
dependencies inbetween devices. I just ignored dependencies between pure
devices (instead changed them into dependencies between drivers) because
I'm still not sure how to handle devices at all. Below is a diff ontop
my dtc-patches to include dependencies between devices too. As said, the
changes to do so are minimal. Of course, the graphs are a bit more
complex, because they then include devices too, but that isn't any
problem for the solving algorithm at all.

diff --git a/scripts/dtc/dependencies.c b/scripts/dtc/dependencies.c
index 06f447b..602ec01 100644
--- a/scripts/dtc/dependencies.c
+++ b/scripts/dtc/dependencies.c

@@ -66,8 +66,10 @@ static void add_deps(struct node *dt, struct node

*node, struct property *prop)
 			continue;
 		}

-		source = find_compatible_not_disabled(node);
-		target = find_compatible_not_disabled(refnode);
+		//source = find_compatible_not_disabled(node);
+		//target = find_compatible_not_disabled(refnode);
+		source = node;
+		target = refnode;
 		if (!source || !target || source == target ||
 				is_parent_of(source, target) ||
 				is_parent_of(target, source))

@@ -385,9 +387,9 @@ static int __init add_deps_lnx(struct device_node

*parent,

 	if (!__of_device_is_available(node))
 		return 0;
-	if (__of_get_property(node, "compatible", NULL)) {
+//	if (__of_get_property(node, "compatible", NULL)) {
 		if (!parent->phandle) {
-			if (__of_get_property(parent, "compatible", NULL))
+//			if (__of_get_property(parent, "compatible", NULL))
 				parent->phandle = 1 + order.max_phandle++;
 		}
 		if (!node->phandle)

@@ -425,7 +427,7 @@ static int __init add_deps_lnx(struct device_node

*parent,
 		if (unlikely(rc))
 			return rc;
 		parent = node; /* change the parent only if node is a driver */
-	}
+//	}
 	for_each_child_of_node(node, child) {
 		rc = add_deps_lnx(parent, child, print_dot);
 		if (unlikely(rc))
-- 
1.8.3.2



To make it easier to see devices in the produced order, here is another
patch on top:

@@ -464,6 +467,8 @@ void __init of_init_print_order(const char *name)
                if (order.order[i]->full_name)
                        pr_cont(" (%s)", order.order[i]->full_name);
                prop = get_property(order.order[i], "compatible");
+               if (!prop)
+                       pr_cont(" -");
                for (cp = of_prop_next_string(prop, NULL); cp;
                     cp = of_prop_next_string(prop, cp))
                        pr_cont(" %s", cp);

With that patch one can do e.g. dtc -t |  grep ' - ' to see which device
nodes are included which don't have a compatible property. For the
omap3-beagle this produces the following 21 additional entries in the
init-order:

aholler at laptopahbt ~/Source/aholler/dtc.git $ dts/make_dtb.sh
dts/omap3-beagle.dts -t | grep ' - '
init 4 0xe4 pinmux_twl4030_pins
(/ocp/pinmux at 48002030/pinmux_twl4030_pins) - (parent 0x14b)
init 10 0x107 clocks (/ocp/cm at 48004000/clocks) - (parent 0x106)
init 17 0x101 clocks (/ocp/prm at 48306000/clocks) - (parent 0x100)
init 226 0x143 clocks (/ocp/scrm at 48002000/clocks) - (parent 0x142)
init 237 0xe1 pinmux_hsusb2_pins
(/ocp/pinmux at 48002030/pinmux_hsusb2_pins) - (parent 0x14b)
init 239 0xe2 pinmux_gpio1_pins (/ocp/pinmux at 48002a00/pinmux_gpio1_pins)
- (parent 0x14d)
init 251 0xec pinmux_hsusb2_2_pins
(/ocp/pinmux at 480025d8/pinmux_hsusb2_2_pins) - (parent 0x18e)
init 255 0xf4 chosen (/chosen) - (parent 0xf3)
init 256 0xf5 aliases (/aliases) - (parent 0xf3)
init 257 0xf6 memory (/memory) - (parent 0xf3)
init 258 0xf7 cpus (/cpus) - (parent 0xf3)
init 269 0x105 clockdomains (/ocp/prm at 48306000/clockdomains) - (parent
0x100)
init 311 0x131 clockdomains (/ocp/cm at 48004000/clockdomains) - (parent 0x106)
init 333 0x149 clockdomains (/ocp/scrm at 48002000/clockdomains) - (parent
0x142)
init 335 0x14c pinmux_uart3_pins
(/ocp/pinmux at 48002030/pinmux_uart3_pins) - (parent 0x14b)
init 343 0x157 codec (/ocp/i2c at 48070000/twl at 48/audio/codec) - (parent 0xf1)
init 398 0x18f choosen (/choosen) - (parent 0xf3)
init 400 0x191 pmu_stat (/leds/pmu_stat) - (parent 0x190)
init 401 0x192 heartbeat (/leds/heartbeat) - (parent 0x190)
init 402 0x193 mmc (/leds/mmc) - (parent 0x190)
init 405 0x196 user (/gpio_keys/user) - (parent 0x195)


Regards,

Alexander Holler