fdt: Add a function to get the alias sequence of a node

Aliases are used to provide U-Boot's numbering of devices, such as:

aliases {
	spi0 = "/spi@12330000";
}

spi@12330000 {
	...
}

This tells us that the SPI controller at 12330000 is considered to be the
first SPI controller (SPI 0). So we have a numbering for the SPI node.

Add a function that returns the numbering for a node assume that it exists
in the list of aliases.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/include/fdtdec.h b/include/fdtdec.h
index a7e6ee7fdfd9afc2284e71cbdc8ee423aa695bcc..f454f7e21781079e555bdfe1f4be0b504aac89d8 100644 (file)
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -345,6 +345,24 @@ int fdtdec_find_aliases_for_id(const void *blob, const char *name,
 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
                        enum fdt_compat_id id, int *node_list, int maxcount);
 
+/**
+ * Get the alias sequence number of a node
+ *
+ * This works out whether a node is pointed to by an alias, and if so, the
+ * sequence number of that alias. Aliases are of the form <base><num> where
+ * <num> is the sequence number. For example spi2 would be sequence number
+ * 2.
+ *
+ * @param blob         Device tree blob (if NULL, then error is returned)
+ * @param base         Base name for alias (before the underscore)
+ * @param node         Node to look up
+ * @param seqp         This is set to the sequence number if one is found,
+ *                     but otherwise the value is left alone
+ * @return 0 if a sequence was found, -ve if not
+ */
+int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
+                        int *seqp);
+
 /*
  * Get the name for a compatible ID
  *

diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index aaa6620cc37c1471bb3bfdc6464eeb2ab5d93485..1b4ae9f417a4a228fb1b745792fef0be5df7b6a6 100644 (file)
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -5,9 +5,11 @@
 
 #ifndef USE_HOSTCC
 #include <common.h>
+#include <errno.h>
 #include <serial.h>
 #include <libfdt.h>
 #include <fdtdec.h>
+#include <linux/ctype.h>
 
 #include <asm/gpio.h>
 
@@ -319,6 +321,50 @@ int fdtdec_add_aliases_for_id(const void *blob, const char *name,
        return num_found;
 }
 
+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;
+       int aliases;
+
+       find_name = fdt_get_name(blob, offset, &find_namelen);
+       debug("Looking for '%s' at %d, name %s\n", base, offset, find_name);
+
+       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;
+               const char *slash;
+               const char *p;
+               int len;
+
+               prop = fdt_getprop_by_offset(blob, prop_offset, &name, &len);
+               debug("   - %s, %s\n", name, prop);
+               if (len < find_namelen || *prop != '/' || prop[len - 1] ||
+                   strncmp(name, base, base_len))
+                       continue;
+
+               slash = strrchr(prop, '/');
+               if (strcmp(slash + 1, find_name))
+                       continue;
+               for (p = name; *p; p++) {
+                       if (isdigit(*p)) {
+                               *seqp = simple_strtoul(p, NULL, 10);
+                               debug("Found seq %d\n", *seqp);
+                               return 0;
+                       }
+               }
+       }
+
+       debug("Not found\n");
+       return -ENOENT;
+}
+
 int fdtdec_check_fdt(void)
 {
        /*