dtc,petitboot: Sort device tree properties by unit number

Currently, dtc will output nodes unordered, which may cause issues when
assigning CPU numbers to NUMA nodes.

This change incorporates a pre-kexec hook to sort the device tree, and
a fix for dtc to order nodes by their unit number, to get a proper
sort ordering.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 110 insertions, 0 deletions

diff --git a/openpower/custom/patches/dtc/dtc-0001-sort-unit-addresses-by-number.patch b/openpower/custom/patches/dtc/dtc-0001-sort-unit-addresses-by-number.patch
new file mode 100644
index 00000000..6f49dbc4
--- /dev/null
+++ b/openpower/custom/patches/dtc/dtc-0001-sort-unit-addresses-by-number.patch
@@ -0,0 +1,110 @@
+Date: Tue, 21 Jan 2014 13:49:35 +1100
+From: Anton Blanchard <anton@samba.org>
+Subject: [PATCH] dtc: Sort unit addresses by number
+
+The sort option in dtc treats unit addresses as strings. This causes
+cpu nodes to end up out of order:
+
+# dtc -s -I fs -O dts /proc/device-tree | grep PowerPC,POWER7
+
+		PowerPC,POWER7@30 {
+		PowerPC,POWER7@68 {
+		PowerPC,POWER7@70 {
+		PowerPC,POWER7@828 {
+		PowerPC,POWER7@860 {
+		PowerPC,POWER7@868 {
+		PowerPC,POWER7@8a0 {
+		PowerPC,POWER7@8b0 {
+		PowerPC,POWER7@8f0 {
+		PowerPC,POWER7@a0 {
+		PowerPC,POWER7@a8 {
+		PowerPC,POWER7@e0 {
+
+If we use this device tree for a kexec boot we end up with a confusing
+layout of logical CPUs:
+
+node 0 cpus: 0-23 72-95
+node 0 size: 32633 MB
+
+node 1 cpus: 24-71
+node 1 size: 32631 MB
+
+The reason for this is that we allocate logical CPU ids as we walk
+through the device tree.
+
+In cmp_subnode, if both nodes have a hex unit address and the
+basenames match, then compare by number.
+
+This fixes the issue:
+
+# dtc -s -I fs -O dts /proc/device-tree | grep PowerPC,POWER7
+		PowerPC,POWER7@30 {
+		PowerPC,POWER7@68 {
+		PowerPC,POWER7@70 {
+		PowerPC,POWER7@a0 {
+		PowerPC,POWER7@a8 {
+		PowerPC,POWER7@e0 {
+		PowerPC,POWER7@828 {
+		PowerPC,POWER7@860 {
+		PowerPC,POWER7@868 {
+		PowerPC,POWER7@8a0 {
+		PowerPC,POWER7@8b0 {
+		PowerPC,POWER7@8f0 {
+
+And the CPU layout is as expected:
+
+node 0 cpus: 0-47
+node 0 size: 32633 MB
+
+node 1 cpus: 48-95
+node 1 size: 32631 MB
+
+Signed-off-by: Anton Blanchard <anton@samba.org>
+--
+
+Index: b/livetree.c
+===================================================================
+--- a/livetree.c
++++ b/livetree.c
+@@ -656,12 +656,38 @@ static void sort_properties(struct node
+ 	free(tbl);
+ }
+ 
++static bool is_hex(const char *str)
++{
++	while (*str) {
++		if (!isxdigit(*str++))
++			return false;
++	}
++
++	return true;
++}
++
+ static int cmp_subnode(const void *ax, const void *bx)
+ {
+-	const struct node *a, *b;
++	struct node *a, *b;
++	const char *a_unit, *b_unit;
++
++	a = *((struct node * const *)ax);
++	b = *((struct node * const *)bx);
++
++	a_unit = get_unitname(a);
++	b_unit = get_unitname(b);
++
++	/* Sort hex unit addresses by number */
++	if (a_unit && b_unit && (a->basenamelen == b->basenamelen) &&
++	    !strncmp(a->name, b->name, a->basenamelen) &&
++	    is_hex(a_unit) && is_hex(b_unit)) {
++		unsigned long long a_num, b_num;
++
++		a_num = strtoull(a_unit, NULL, 16);
++		b_num = strtoull(b_unit, NULL, 16);
+ 
+-	a = *((const struct node * const *)ax);
+-	b = *((const struct node * const *)bx);
++		return (a_num > b_num) - (a_num < b_num);
++	}
+ 
+ 	return strcmp(a->name, b->name);
+ }