[U-Boot] [PATCH] dm: fdtdec: Check full path for alias

[Michal Simek]

Fix fdtdec_get_alias_seq() which is not checking full path to certain
node and it incorrectly provides incorrect seq number.
Checking full path ensure that if alias is present correct seq number is
return.
This problem was found on ZynqMP zcu102 where are several I2C muxes
where the first bus name is i2c at 0 and for following muxes incorrect seq
numbers are return.

Signed-off-by: Michal Simek <michal.simek at xilinx.com>
---

I am not sure if there is any macro for max alias length which I can use
instead of new macro.

Before:
ZynqMP> i2c bus
Bus 0:  i2c at ff020000
   20: gpio at 20, offset len 1, flags 0
   21: gpio at 21, offset len 1, flags 0
   75: i2cswitch at 75, offset len 1, flags 0
Bus 750:        i2c at 0
Bus 751:        i2c at 1
Bus 752:        i2c at 2
Bus 1:  i2c at ff030000
   74: i2cswitch at 74, offset len 1, flags 0
   75: i2cswitch at 75, offset len 1, flags 0
Bus 750:        i2c at 0
Bus 751:        i2c at 1
Bus 752:        i2c at 2
Bus 1743:       i2c at 3
Bus 1744:       i2c at 4
Bus 750:        i2c at 0
Bus 751:        i2c at 1
Bus 752:        i2c at 2
Bus 1743:       i2c at 3
Bus 1744:       i2c at 4
Bus 1755:       i2c at 5
Bus 1756:       i2c at 6
Bus 1757:       i2c at 7

After:
ZynqMP> i2c bus
Bus 0:	i2c at ff020000
   20: gpio at 20, offset len 1, flags 0
   21: gpio at 21, offset len 1, flags 0
   75: i2cswitch at 75, offset len 1, flags 0
Bus 750:	i2c at 0
Bus 751:	i2c at 1
Bus 752:	i2c at 2
Bus 1:	i2c at ff030000
   74: i2cswitch at 74, offset len 1, flags 0
   75: i2cswitch at 75, offset len 1, flags 0
Bus 1740:	i2c at 0
Bus 1741:	i2c at 1
Bus 1742:	i2c at 2
Bus 1743:	i2c at 3
Bus 1744:	i2c at 4
Bus 1750:	i2c at 0
Bus 1751:	i2c at 1
Bus 1752:	i2c at 2
Bus 1753:	i2c at 3
Bus 1754:	i2c at 4
Bus 1755:	i2c at 5
Bus 1756:	i2c at 6
Bus 1757:	i2c at 7

Which reflects my aliases
i2c0 = &i2c0;
i2c750 = &i2c0_75_0;
i2c751 = &i2c0_75_1;
i2c752 = &i2c0_75_2;
i2c1 = &i2c1;
i2c1740 = &i2c1_74_0;
i2c1741 = &i2c1_74_1;
i2c1742 = &i2c1_74_2;
i2c1743 = &i2c1_74_3;
i2c1744 = &i2c1_74_4;
i2c1750 = &i2c1_75_0;
i2c1751 = &i2c1_75_1;
i2c1752 = &i2c1_75_2;
i2c1753 = &i2c1_75_3;
i2c1754 = &i2c1_75_4;
i2c1755 = &i2c1_75_5;
i2c1756 = &i2c1_75_6;
i2c1757 = &i2c1_75_7;

---
 lib/fdtdec.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 70acc29c924d..79efcf0cd6b0 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -506,6 +506,8 @@ int fdtdec_add_aliases_for_id(const void *blob, const char *name,
 	return num_found;
 }
 
+#define FDT_ALIAS_PATH_LEN	64
+
 int fdtdec_get_alias_seq(const void *blob, const char *base, int offset,
 			 int *seqp)
 {
@@ -514,9 +516,13 @@ int fdtdec_get_alias_seq(const void *blob, const char *base, int offset,
 	int find_namelen;
 	int prop_offset;
 	int aliases;
+	char buf[FDT_ALIAS_PATH_LEN];
+
+	fdt_get_path(blob, offset, buf, sizeof(buf));
 
 	find_name = fdt_get_name(blob, offset, &find_namelen);
-	debug("Looking for '%s' at %d, name %s\n", base, offset, find_name);
+	debug("Looking for '%s' at %d, name %s, buf %s\n",
+	      base, offset, find_name, buf);
 
 	aliases = fdt_path_offset(blob, "/aliases");
 	for (prop_offset = fdt_first_property_offset(blob, aliases);
@@ -533,6 +539,13 @@ int fdtdec_get_alias_seq(const void *blob, const char *base, int offset,
 		    strncmp(name, base, base_len))
 			continue;
 
+		if (len >= FDT_ALIAS_PATH_LEN)
+			printf("Too long path in aliases node\n");
+
+		/* Check full path first not to point to incorrect alias */
+		if (strncmp(prop, buf, min(len, FDT_ALIAS_PATH_LEN)))
+			continue;
+
 		slash = strrchr(prop, '/');
 		if (strcmp(slash + 1, find_name))
 			continue;
-- 
1.9.1