[PATCH] Add MPC8641 HPCN Device Tree Source file.

Signed-off-by: Jon Loeliger <redacted>
---

As per list discussion, let's add device tree source files
under powerpc/boot/dts.  If nothing else, it is a starting point.

 arch/powerpc/boot/dts/mpc8641_hpcn.dts |  338 ++++++++++++++++++++++++++++++++
 1 files changed, 338 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/boot/dts/mpc8641_hpcn.dts b/arch/powerpc/boot/dts/mpc8641_hpcn.dts
new file mode 100644
index 0000000..55a8167
--- /dev/null
+++ b/arch/powerpc/boot/dts/mpc8641_hpcn.dts

@@ -0,0 +1,338 @@
+/*
+ * MPC8641 HPCN Device Tree Source
+ *
+ * Copyright 2006 Freescale Semiconductor Inc.
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+
+/ {
+	model = "MPC8641HPCN";
+	compatible = "mpc86xx";
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	cpus {
+		#cpus = <2>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		PowerPC,8641@0 {
+			device_type = "cpu";
+			reg = <0>;
+			d-cache-line-size = <20>;	// 32 bytes
+			i-cache-line-size = <20>;	// 32 bytes
+			d-cache-size = <8000>;		// L1, 32K
+			i-cache-size = <8000>;		// L1, 32K
+			timebase-frequency = <0>;	// 33 MHz, from uboot
+			bus-frequency = <0>;		// From uboot
+			clock-frequency = <0>;		// From uboot
+			32-bit;
+			linux,boot-cpu;
+		};
+		PowerPC,8641@1 {
+			device_type = "cpu";
+			reg = <1>;
+			d-cache-line-size = <20>;	// 32 bytes
+			i-cache-line-size = <20>;	// 32 bytes
+			d-cache-size = <8000>;		// L1, 32K
+			i-cache-size = <8000>;		// L1, 32K
+			timebase-frequency = <0>;	// 33 MHz, from uboot
+			bus-frequency = <0>;		// From uboot
+			clock-frequency = <0>;		// From uboot
+			32-bit;
+		};
+	};
+
+	memory {
+		device_type = "memory";
+		reg = <00000000 40000000>;	// 1G at 0x0
+	};
+
+	soc8641@f8000000 {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		#interrupt-cells = <2>;
+		device_type = "soc";
+		ranges = <0 f8000000 00100000>;
+		reg = <f8000000 00100000>;	// CCSRBAR 1M
+		bus-frequency = <0>;
+
+		i2c@3000 {
+			device_type = "i2c";
+			compatible = "fsl-i2c";
+			reg = <3000 100>;
+			interrupts = <2b 2>;
+			interrupt-parent = <40000>;
+			dfsrr;
+		};
+
+		i2c@3100 {
+			device_type = "i2c";
+			compatible = "fsl-i2c";
+			reg = <3100 100>;
+			interrupts = <2b 2>;
+			interrupt-parent = <40000>;
+			dfsrr;
+		};
+
+		mdio@24520 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "mdio";
+			compatible = "gianfar";
+			reg = <24520 20>;
+			linux,phandle = <24520>;
+			ethernet-phy@0 {
+				linux,phandle = <2452000>;
+				interrupt-parent = <40000>;
+				interrupts = <4a 1>;
+				reg = <0>;
+				device_type = "ethernet-phy";
+			};
+			ethernet-phy@1 {
+				linux,phandle = <2452001>;
+				interrupt-parent = <40000>;
+				interrupts = <4a 1>;
+				reg = <1>;
+				device_type = "ethernet-phy";
+			};
+			ethernet-phy@2 {
+				linux,phandle = <2452002>;
+				interrupt-parent = <40000>;
+				interrupts = <4a 1>;
+				reg = <2>;
+				device_type = "ethernet-phy";
+			};
+			ethernet-phy@3 {
+				linux,phandle = <2452003>;
+				interrupt-parent = <40000>;
+				interrupts = <4a 1>;
+				reg = <3>;
+				device_type = "ethernet-phy";
+			};
+		};
+
+		ethernet@24000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <24000 1000>;
+			address = [ 00 E0 0C 00 73 00 ];
+			interrupts = <1d 2 1e 2 22 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452000>;
+		};
+
+		ethernet@25000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <25000 1000>;
+			address = [ 00 E0 0C 00 73 01 ];
+			interrupts = <23 2 24 2 28 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452001>;
+		};
+		
+		ethernet@26000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <26000 1000>;
+			address = [ 00 E0 0C 00 02 FD ];
+			interrupts = <1F 2 20 2 21 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452002>;
+		};
+
+		ethernet@27000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <27000 1000>;
+			address = [ 00 E0 0C 00 03 FD ];
+			interrupts = <25 2 26 2 27 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452003>;
+		};
+		serial@4500 {
+			device_type = "serial";
+			compatible = "ns16550";
+			reg = <4500 100>;
+			clock-frequency = <0>;
+			interrupts = <2a 2>;
+			interrupt-parent = <40000>;
+		};
+
+		serial@4600 {
+			device_type = "serial";
+			compatible = "ns16550";
+			reg = <4600 100>;
+			clock-frequency = <0>;
+			interrupts = <1c 2>;
+			interrupt-parent = <40000>;
+		};
+
+		pci@8000 {
+			compatible = "86xx";
+			device_type = "pci";
+			#interrupt-cells = <1>;
+			#size-cells = <2>;
+			#address-cells = <3>;
+			reg = <8000 1000>;
+			bus-range = <0 fe>;
+			ranges = <02000000 0 80000000 80000000 0 20000000
+				  01000000 0 00000000 e2000000 0 00100000>;
+			clock-frequency = <1fca055>;
+			interrupt-parent = <40000>;
+			interrupts = <18 2>;
+			interrupt-map-mask = <f800 0 0 7>;
+			interrupt-map = <
+				/* IDSEL 0x11 */
+				8800 0 0 1 4d0 3 2
+				8800 0 0 2 4d0 4 2
+				8800 0 0 3 4d0 5 2
+				8800 0 0 4 4d0 6 2
+
+				/* IDSEL 0x12 */
+				9000 0 0 1 4d0 4 2
+				9000 0 0 2 4d0 5 2
+				9000 0 0 3 4d0 6 2
+				9000 0 0 4 4d0 3 2
+
+				/* IDSEL 0x13 */
+				9800 0 0 1 4d0 0 0
+				9800 0 0 2 4d0 0 0
+				9800 0 0 3 4d0 0 0
+				9800 0 0 4 4d0 0 0
+
+				/* IDSEL 0x14 */
+				a000 0 0 1 4d0 0 0
+				a000 0 0 2 4d0 0 0
+				a000 0 0 3 4d0 0 0
+				a000 0 0 4 4d0 0 0
+
+				/* IDSEL 0x15 */
+				a800 0 0 1 4d0 0 0
+				a800 0 0 2 4d0 0 0
+				a800 0 0 3 4d0 0 0
+				a800 0 0 4 4d0 0 0
+
+				/* IDSEL 0x16 */
+				b000 0 0 1 4d0 0 0
+				b000 0 0 2 4d0 0 0
+				b000 0 0 3 4d0 0 0
+				b000 0 0 4 4d0 0 0
+
+				/* IDSEL 0x17 */
+				b800 0 0 1 4d0 0 0
+				b800 0 0 2 4d0 0 0
+				b800 0 0 3 4d0 0 0
+				b800 0 0 4 4d0 0 0
+
+				/* IDSEL 0x18 */
+				c000 0 0 1 4d0 0 0
+				c000 0 0 2 4d0 0 0
+				c000 0 0 3 4d0 0 0
+				c000 0 0 4 4d0 0 0
+
+				/* IDSEL 0x19 */
+				c800 0 0 1 4d0 0 0
+				c800 0 0 2 4d0 0 0
+				c800 0 0 3 4d0 0 0
+				c800 0 0 4 4d0 0 0
+
+				/* IDSEL 0x1a */
+				d000 0 0 1 4d0 6 2
+				d000 0 0 2 4d0 3 2
+				d000 0 0 3 4d0 4 2
+				d000 0 0 4 4d0 5 2
+
+
+				/* IDSEL 0x1b */
+				d800 0 0 1 4d0 5 2
+				d800 0 0 2 4d0 0 0
+				d800 0 0 3 4d0 0 0
+				d800 0 0 4 4d0 0 0
+
+				/* IDSEL 0x1c */
+				e000 0 0 1 4d0 9 2
+				e000 0 0 2 4d0 a 2
+				e000 0 0 3 4d0 c 2
+				e000 0 0 4 4d0 7 2
+
+				/* IDSEL 0x1d */
+				e800 0 0 1 4d0 9 2
+				e800 0 0 2 4d0 a 2
+				e800 0 0 3 4d0 b 2
+				e800 0 0 4 4d0 0 0
+
+				/* IDSEL 0x1e */
+				f000 0 0 1 4d0 c 2
+				f000 0 0 2 4d0 0 0
+				f000 0 0 3 4d0 0 0
+				f000 0 0 4 4d0 0 0
+
+				/* IDSEL 0x1f */
+				f800 0 0 1 4d0 6 2
+				f800 0 0 2 4d0 0 0
+				f800 0 0 3 4d0 0 0
+				f800 0 0 4 4d0 0 0
+				>;
+			i8259@4d0 {
+				clock-frequency = <0>;
+				interrupt-controller;
+				device_type = "interrupt-controller";
+				#address-cells = <0>;
+				#interrupt-cells = <2>;
+				built-in;
+				compatible = "chrp,iic";
+                	        big-endian;
+				interrupts = <49 2>;
+				interrupt-parent = <40000>;
+			};
+
+		};
+		pic@40000 {
+			linux,phandle = <40000>;
+			clock-frequency = <0>;
+			interrupt-controller;
+			#address-cells = <0>;
+			#interrupt-cells = <2>;
+			reg = <40000 40000>;
+			built-in;
+			compatible = "chrp,open-pic";
+			device_type = "open-pic";
+                        big-endian;
+			interrupts = <
+				10 2 11 2 12 2 13 2
+				14 2 15 2 16 2 17 2
+				18 2 19 2 1a 2 1b 2
+				1c 2 1d 2 1e 2 1f 2
+				20 2 21 2 22 2 23 2
+				24 2 25 2 26 2 27 2
+				28 2 29 2 2a 2 2b 2
+				2c 2 2d 2 2e 2 2f 2
+				30 2 31 2 32 2 33 2
+				34 2 35 2 36 2 37 2
+				38 2 39 2 2a 2 3b 2
+				3c 2 3d 2 3e 2 3f 2
+				48 1 49 2 4a 1
+				>;
+			interrupt-parent = <40000>;
+		};
+	};
+};

-- 
2006_06_07.01.gittree_pull-dirty

On Aug 2, 2006, at 1:48 PM, Jon Loeliger wrote:

Signed-off-by: Jon Loeliger <redacted>
---

As per list discussion, let's add device tree source files
under powerpc/boot/dts.  If nothing else, it is a starting point.

 arch/powerpc/boot/dts/mpc8641_hpcn.dts |  338 +++++++++++++++++++++ 
+++++++++++
 1 files changed, 338 insertions(+), 0 deletions(-)

Do we want to go ahead and fix the mac address field having the wrong  
name?

- kumar

Hello.

Kumar Gala wrote:

Do we want to go ahead and fix the mac address field having the wrong  
name?

    If you mean "address" instead of "local-mac-address" then I guess 
Documentation/powerpc/booting-without-of.txt should also be changed since it 
has "address". And arch/powerpc/sysdev/fsl_soc.c as well..

quoted

+		ethernet@24000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <24000 1000>;
+			address = [ 00 E0 0C 00 73 00 ];
+			interrupts = <1d 2 1e 2 22 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452000>;
+		};
+
+		ethernet@25000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <25000 1000>;
+			address = [ 00 E0 0C 00 73 01 ];
+			interrupts = <23 2 24 2 28 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452001>;
+		};
+		
+		ethernet@26000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <26000 1000>;
+			address = [ 00 E0 0C 00 02 FD ];
+			interrupts = <1F 2 20 2 21 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452002>;
+		};
+
+		ethernet@27000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <27000 1000>;
+			address = [ 00 E0 0C 00 03 FD ];
+			interrupts = <25 2 26 2 27 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452003>;
+		};

WBR, Sergei

On Aug 2, 2006, at 2:33 PM, Sergei Shtylyov wrote:

Hello.

Kumar Gala wrote:

quoted

Do we want to go ahead and fix the mac address field having the  
wrong  name?

   If you mean "address" instead of "local-mac-address" then I  
guess Documentation/powerpc/booting-without-of.txt should also be  
changed since it has "address". And arch/powerpc/sysdev/fsl_soc.c  
as well..

Yeah, fsl_soc.c should be updated to support both forms for a period  
of time.

- kumar

quoted

quoted

+		ethernet@24000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <24000 1000>;
+			address = [ 00 E0 0C 00 73 00 ];
+			interrupts = <1d 2 1e 2 22 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452000>;
+		};
+
+		ethernet@25000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <25000 1000>;
+			address = [ 00 E0 0C 00 73 01 ];
+			interrupts = <23 2 24 2 28 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452001>;
+		};
+		
+		ethernet@26000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <26000 1000>;
+			address = [ 00 E0 0C 00 02 FD ];
+			interrupts = <1F 2 20 2 21 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452002>;
+		};
+
+		ethernet@27000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			device_type = "network";
+			model = "TSEC";
+			compatible = "gianfar";
+			reg = <27000 1000>;
+			address = [ 00 E0 0C 00 03 FD ];
+			interrupts = <25 2 26 2 27 2>;
+			interrupt-parent = <40000>;
+			phy-handle = <2452003>;
+		};

WBR, Sergei

On Wed, 2006-08-02 at 14:24, Kumar Gala wrote:

On Aug 2, 2006, at 1:48 PM, Jon Loeliger wrote:

quoted

Signed-off-by: Jon Loeliger <redacted>
---

As per list discussion, let's add device tree source files
under powerpc/boot/dts.  If nothing else, it is a starting point.

 arch/powerpc/boot/dts/mpc8641_hpcn.dts |  338 +++++++++++++++++++++ 
+++++++++++
 1 files changed, 338 insertions(+), 0 deletions(-)

Do we want to go ahead and fix the mac address field having the wrong  
name?

- kumar

Yeah, we have lined up Matt to make a comprehensive
update for this.  Can we take my patch as-is?  Matt will
follow up with a clean sweep, including fsl_socl.c, to
fix it all in one swell foop.

quoted

diff --git a/arch/powerpc/boot/dts/mpc8641_hpcn.dts b/arch/powerpc/ 

boot/dts/mpc8641_hpcn.dts
new file mode 100644
index 0000000..55a8167

--- /dev/null
+++ b/arch/powerpc/boot/dts/mpc8641_hpcn.dts

@@ -0,0 +1,338 @@
+/*
+ * MPC8641 HPCN Device Tree Source
+ *

Any chance we can avoid quoting-back the largely irrelevant
parts of a post like this in the future?

Thanks,
jdl

On Aug 2, 2006, at 3:11 PM, Jon Loeliger wrote:

On Wed, 2006-08-02 at 14:24, Kumar Gala wrote:

quoted

On Aug 2, 2006, at 1:48 PM, Jon Loeliger wrote:

quoted

Signed-off-by: Jon Loeliger <redacted>
---

As per list discussion, let's add device tree source files
under powerpc/boot/dts.  If nothing else, it is a starting point.

 arch/powerpc/boot/dts/mpc8641_hpcn.dts |  338 +++++++++++++++++++++
+++++++++++
 1 files changed, 338 insertions(+), 0 deletions(-)

Do we want to go ahead and fix the mac address field having the wrong
name?

- kumar

Yeah, we have lined up Matt to make a comprehensive
update for this.  Can we take my patch as-is?  Matt will
follow up with a clean sweep, including fsl_socl.c, to
fix it all in one swell foop.

I think this is one that is clearly something that should be fixed  
before acceptance.  Since we are talking about a dozen lines of  
modifications.  Especially since at this point having the .dts in the  
tree doesn't really effect anything inside the kernel tree.

- kumar

quoted

quoted

diff --git a/arch/powerpc/boot/dts/mpc8641_hpcn.dts b/arch/powerpc/

boot/dts/mpc8641_hpcn.dts
new file mode 100644
index 0000000..55a8167

--- /dev/null
+++ b/arch/powerpc/boot/dts/mpc8641_hpcn.dts

@@ -0,0 +1,338 @@
+/*
+ * MPC8641 HPCN Device Tree Source
+ *

Any chance we can avoid quoting-back the largely irrelevant
parts of a post like this in the future?

Thanks,
jdl

On Wed, 2006-08-02 at 15:30, Kumar Gala wrote:

quoted

Yeah, we have lined up Matt to make a comprehensive
update for this.  Can we take my patch as-is?  Matt will
follow up with a clean sweep, including fsl_socl.c, to
fix it all in one swell foop.

I think this is one that is clearly something that should be fixed  
before acceptance.  Since we are talking about a dozen lines of  
modifications.  Especially since at this point having the .dts in the  
tree doesn't really effect anything inside the kernel tree.

- kumar

On the other hand, this matches what the kernel implements
today, and is already in use by several people around the
world.  It _does_ have an affect and is based on things
inside the kernel tree today as it is.

Thanks,
jdl

On Aug 2, 2006, at 3:36 PM, Jon Loeliger wrote:

On Wed, 2006-08-02 at 15:30, Kumar Gala wrote:

quoted

quoted

Yeah, we have lined up Matt to make a comprehensive
update for this.  Can we take my patch as-is?  Matt will
follow up with a clean sweep, including fsl_socl.c, to
fix it all in one swell foop.

I think this is one that is clearly something that should be fixed
before acceptance.  Since we are talking about a dozen lines of
modifications.  Especially since at this point having the .dts in the
tree doesn't really effect anything inside the kernel tree.

- kumar

On the other hand, this matches what the kernel implements
today, and is already in use by several people around the
world.  It _does_ have an affect and is based on things
inside the kernel tree today as it is.

True, but the people that are running this dont really care if the  
dts is in the kernel or not. I think having an error in the kernel  
tree that we know about is more of an issue.  Its something we all  
agree needs to be fixed.

Here is the code modification to fsl_soc.c, I'm sure we can get this  
fixed push into 2.6.18 if desired.

if(mac_addr = get_property(np, "address", NULL))
   memcpy(gfar_data.mac_addr, mac_addr, 6);

if(mac_addr = get_property(np, "local-mac-address", NULL);
   memcpy(gfar_data.mac_addr, mac_addr, 6);

- kumar

Hello.

Kumar Gala wrote:

Here is the code modification to fsl_soc.c, I'm sure we can get this  
fixed push into 2.6.18 if desired.

if(mac_addr = get_property(np, "address", NULL))
   memcpy(gfar_data.mac_addr, mac_addr, 6);

if(mac_addr = get_property(np, "local-mac-address", NULL);
   memcpy(gfar_data.mac_addr, mac_addr, 6);

    BTW, doesn't it also have sense to convert gianfar.c to using of_device 
instead of platform_device?

WBR, Sergei

On Aug 3, 2006, at 10:49 AM, Sergei Shtylyov wrote:

Hello.

Kumar Gala wrote:

quoted

Here is the code modification to fsl_soc.c, I'm sure we can get  
this  fixed push into 2.6.18 if desired.

quoted

if(mac_addr = get_property(np, "address", NULL))
   memcpy(gfar_data.mac_addr, mac_addr, 6);
if(mac_addr = get_property(np, "local-mac-address", NULL);
   memcpy(gfar_data.mac_addr, mac_addr, 6);

   BTW, doesn't it also have sense to convert gianfar.c to using  
of_device instead of platform_device?

We can't do that until all consumers from arch/ppc are gone.

- k

On Wed, 2006-08-02 at 14:24 -0500, Kumar Gala wrote:

Do we want to go ahead and fix the mac address field having the wrong
name?

Yes please.

-Hollis

On Wed, 2006-08-02 at 13:48 -0500, Jon Loeliger wrote:

+               PowerPC,8641@0 {
+                       device_type = "cpu";
+                       reg = <0>;
+                       d-cache-line-size = <20>;       // 32 bytes
+                       i-cache-line-size = <20>;       // 32 bytes
+                       d-cache-size = <8000>;          // L1, 32K
+                       i-cache-size = <8000>;          // L1, 32K
+                       timebase-frequency = <0>;       // 33 MHz,
from uboot
+                       bus-frequency = <0>;            // From uboot
+                       clock-frequency = <0>;          // From uboot
+                       32-bit;
+                       linux,boot-cpu;
+               }; 

I need to do something similar for Xen, so I was curious: I guess the
preferred way for runtime software to fill in values is by *overwriting*
bogus values inserted at compile time?

The other alternative would be for the runtime code to insert new
properties (presumably via memmove()), but overwriting definitely seems
simpler.

-Hollis

On Wed, Aug 02, 2006 at 02:50:17PM -0500, Hollis Blanchard wrote:

On Wed, 2006-08-02 at 13:48 -0500, Jon Loeliger wrote:

quoted

+               PowerPC,8641@0 {
+                       device_type = "cpu";
+                       reg = <0>;
+                       d-cache-line-size = <20>;       // 32 bytes
+                       i-cache-line-size = <20>;       // 32 bytes
+                       d-cache-size = <8000>;          // L1, 32K
+                       i-cache-size = <8000>;          // L1, 32K
+                       timebase-frequency = <0>;       // 33 MHz,
from uboot
+                       bus-frequency = <0>;            // From uboot
+                       clock-frequency = <0>;          // From uboot
+                       32-bit;
+                       linux,boot-cpu;
+               }; 

I need to do something similar for Xen, so I was curious: I guess the
preferred way for runtime software to fill in values is by *overwriting*
bogus values inserted at compile time?

The other alternative would be for the runtime code to insert new
properties (presumably via memmove()), but overwriting definitely seems
simpler.

Two reasons you may want to overwrite instead of insert a new one (at
least for now):

1) Strictly opinion: Its nice to be able to see the completely
functional tree and not one that's missing a critical property
that is magically inserted behind the scenes.

2) Strictly practical for now: If you plan on using a zImage with
the fdt patches that are being discussed right now, the fdt code
doesn't currently support inserting a new property, only modifying an
existing one.  Patches always welcome though! :)

Mark