Hi Simon,

On Sat, 28 Mar 2020 at 22:06, Simon Glass sjg@chromium.org wrote:

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?

No, why would I want to do that? Why is this an odd case? I thought aliases are supposed to match on full path, no?

...

•   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

Regards, -Vladimir

On Sat, 28 Mar 2020 at 23:00, Simon Glass sjg@chromium.org wrote:

Hi Vladimir,

On Sat, 28 Mar 2020 at 14:25, Vladimir Oltean olteanv@gmail.com wrote:

...

Hi Simon,

On Sat, 28 Mar 2020 at 22:06, Simon Glass sjg@chromium.org wrote:

...

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?

No, why would I want to do that?

Because it uses a different algorithm - see of_alias_get_id(). It might already work.

...

Why is this an odd case? I thought aliases are supposed to match on full path, no?

Because we've been using the current algorithm for 5+ years without any comment.

Note that fdt_get_path() likely takes a long time in SPL and before relocation.

Regards, Simon

So we have no disagreement about the fact that the function doesn't do what's written on the box, and that the implementation for CONFIG_OF_LIVE=y and CONFIG_OF_LIVE=n yields different results, however your argument is that we should leave it alone because nobody noticed thus far? Don't I count?

Regards, -Vladimir