[v2 PATCH] of/flattree: Fix unhandled OF_DT_NOP tag when unflattening the device tree

[v2 PATCH] of/flattree: Fix unhandled OF_DT_NOP tag when unflattening the device tree

[Grant Likely]

From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>

NOPs within the property section are skipped, but NOPs between
OF_DT_END_NODE and OF_DT_BEGIN_NODE were not. My firmware NOPs out
entire nodes depending on various environment parameters.

of_scan_flat_dt already handles NOP more generally.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
v2 - adapted to new location of unflatten_dt_node().

Jason, please test against 2.6.34-rc1

 drivers/of/fdt.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 406757a..dee4fb5 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -376,8 +376,11 @@ unsigned long __init unflatten_dt_node(unsigned long mem,
 		if (!np->type)
 			np->type = "<NULL>";
 	}
-	while (tag == OF_DT_BEGIN_NODE) {
-		mem = unflatten_dt_node(mem, p, np, allnextpp, fpsize);
+	while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
+		if (tag == OF_DT_NOP)
+			*p += 4;
+		else
+			mem = unflatten_dt_node(mem, p, np, allnextpp, fpsize);
 		tag = be32_to_cpup((__be32 *)(*p));
 	}
 	if (tag != OF_DT_END_NODE) {

Re: [v2 PATCH] of/flattree: Fix unhandled OF_DT_NOP tag when unflattening the device tree

[David Gibson]

On Fri, Mar 19, 2010 at 02:01:49PM -0600, Grant Likely wrote:
> From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
> 
> NOPs within the property section are skipped, but NOPs between
> OF_DT_END_NODE and OF_DT_BEGIN_NODE were not. My firmware NOPs out
> entire nodes depending on various environment parameters.
> 
> of_scan_flat_dt already handles NOP more generally.

Fwiw, there's a test program in the libfdt/dtc tree called "nopulate"
which will liberally spread NOPs through a device tree blob (one
between every other tag), which might be useful for testing this

-- 
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