Re: [PATCH] fdtdec: use full path in fdtdec_get_alias_seq comparison

Hi Vladimir,

On Fri, 27 Mar 2020 at 11:29, Vladimir Oltean olteanv@gmail.com wrote:

From: Vladimir Oltean vladimir.oltean@nxp.com

Currently fdtdec_get_alias_seq() calls fdt_get_name() which returns only the name of the leaf node. So it needs to also trim the path of the alias to the leaf name only, leading to imperfect matches.

This means that the following aliases:

/aliases {
    eth0 = "/dspi@2120000/ethernet-switch@0/ports/port@0";
    eth1 = "/pcie@1f0000000/pci@0,5/ports/port@0";
};

will make fdtdec_get_alias_seq to return a seq of zero for both aliases, as the match will only take place on the "port@0" portion.

Fix this by calling fdt_get_path and comparing the full path of the alias.

Fixes: 5c33c9fdbb3f ("fdt: Add a function to get the alias sequence of a node") Signed-off-by: Vladimir Oltean vladimir.oltean@nxp.com

---

lib/fdtdec.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/lib/fdtdec.c b/lib/fdtdec.c index eb11fc898e30..55c1b36e823b 100644 --- a/lib/fdtdec.c +++ b/lib/fdtdec.c @@ -455,13 +455,14 @@ int fdtdec_get_alias_seq(const void *blob, const char *base, int offset, int *seqp) { int base_len = strlen(base);

•   const char *find_name;
  

•   int find_namelen;
    int prop_offset;
  

•   char path[64];
  

•   int path_len;
    int aliases;
  
  

•   find_name = fdt_get_name(blob, offset, &find_namelen);
  

•   debug("Looking for '%s' at %d, name %s\n", base, offset, find_name);
  

•   fdt_get_path(blob, offset, path, sizeof(path));
  

This is really slow. I would prefer not to change this for what seems like an odd case.

Can you enable CONFIG_OF_LIVE instead?

•   path_len = strlen(path);
  

•   debug("Looking for '%s' at %d, path %s\n", base, offset, path);
  
    aliases = fdt_path_offset(blob, "/aliases");
    for (prop_offset = fdt_first_property_offset(blob, aliases);
  

@@ -469,17 +470,15 @@ int fdtdec_get_alias_seq(const void *blob, const char *base, int offset, prop_offset = fdt_next_property_offset(blob, prop_offset)) { const char *prop; const char *name;

•           const char *slash;
            int len, val;
  
            prop = fdt_getprop_by_offset(blob, prop_offset, &name, &len);
            debug("   - %s, %s\n", name, prop);
  

•           if (len < find_namelen || *prop != '/' || prop[len - 1] ||
  

•           if (len < path_len || *prop != '/' || prop[len - 1] ||
                strncmp(name, base, base_len))
                    continue;
  
  

•           slash = strrchr(prop, '/');
  

•           if (strcmp(slash + 1, find_name))
  

•           if (strcmp(prop, path))
                    continue;
            val = trailing_strtol(name);
            if (val != -1) {
  

-- 2.17.1

Regards, Simon