[U-Boot] [PATCH 2/4] fdt: Introduce fdtdec_get_alias_highest_id()

[Michal Simek]

On 31. 01. 19 11:04, Simon Glass wrote:
> Hi Michal,
> 
> On Fri, 18 Jan 2019 at 08:13, Michal Simek <michal.simek at xilinx.com> wrote:
>>
>> Find out the highest alias ID used for certain subsystem.
>> This call will be used for alocating IDs for i2c buses which are not
>> described in DT.
>>
>> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
>> ---
>>
>>  include/fdtdec.h | 13 +++++++++++++
>>  lib/fdtdec.c     | 33 +++++++++++++++++++++++++++++++++
>>  2 files changed, 46 insertions(+)
>>
>> diff --git a/include/fdtdec.h b/include/fdtdec.h
>> index f1bcbf837ffb..c2dd87ede226 100644
>> --- a/include/fdtdec.h
>> +++ b/include/fdtdec.h
>> @@ -626,6 +626,19 @@ int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
>>                          int *seqp);
>>
>>  /**
>> + * Get the highest alias number for susbystem.
>> + *
>> + * It parses all aliases and find out highest recorded alias for subsystem.
>> + * Aliases are of the form <base><num> where <num> is the sequence number.
>> + *
>> + * @param blob         Device tree blob (if NULL, then error is returned)
>> + * @param base         Base name for alias susbystem (before the number)
>> + *
>> + * @return 0 highest alias ID, -1 if not found
>> + */
>> +int fdtdec_get_alias_highest_id(const void *blob, const char *base);
>> +
>> +/**
>>   * Get a property from the /chosen node
>>   *
>>   * @param blob         Device tree blob (if NULL, then NULL is returned)
>> diff --git a/lib/fdtdec.c b/lib/fdtdec.c
>> index 18663ce6bdac..55811975ef54 100644
>> --- a/lib/fdtdec.c
>> +++ b/lib/fdtdec.c
>> @@ -549,6 +549,39 @@ int fdtdec_get_alias_seq(const void *blob, const char *base, int offset,
>>         return -ENOENT;
>>  }
>>
>> +int fdtdec_get_alias_highest_id(const void *blob, const char *base)
>> +{
>> +       int base_len = strlen(base);
>> +       int prop_offset;
>> +       int aliases;
>> +       int max = -1;
>> +
>> +       debug("Looking for highest alias id for '%s'\n", base);
>> +
>> +       aliases = fdt_path_offset(blob, "/aliases");
>> +       for (prop_offset = fdt_first_property_offset(blob, aliases);
>> +            prop_offset > 0;
>> +            prop_offset = fdt_next_property_offset(blob, prop_offset)) {
>> +               const char *prop;
>> +               const char *name;
>> +               int len, val;
>> +
>> +               prop = fdt_getprop_by_offset(blob, prop_offset, &name, &len);
>> +               debug("   - %s, %s\n", name, prop);
>> +               if (*prop != '/' || prop[len - 1] ||
>> +                   strncmp(name, base, base_len))
>> +                       continue;
>> +
>> +               val = trailing_strtol(name);
>> +               if (val > max) {
>> +                       debug("Found seq %d\n", val);
>> +                       max = val;
>> +               }
>> +       }
>> +
>> +       return max;
> 
> This looks right to me. Can you please add a test that calls this for
> a few sandbox aliases?

let's see how this can be done.

M