vsprintf: Add %p extension "%pOF" for device tree
90% of the usage of device node's full_name is printing it out in a
kernel message. However, storing the full path for every node is
wasteful and redundant. With a custom format specifier, we can generate
the full path at run-time and eventually remove the full path from every
node.
For instance typical use is:
pr_info("Frobbing node %s\n", node->full_name);
Which can be written now as:
pr_info("Frobbing node %pOF\n", node);
'%pO' is the base specifier to represent kobjects with '%pOF'
representing struct device_node. Currently, struct device_node is the
only supported type of kobject.
More fine-grained control of formatting includes printing the name,
flags, path-spec name and others, explained in the documentation entry.
Originally written by Pantelis, but pretty much rewrote the core
function using existing string/number functions. The 2 passes were
unnecessary and have been removed. Also, updated the checkpatch.pl
check. The unittest code was written by Grant Likely.
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 2d41de3..ff8f126 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -31,6 +31,7 @@
#include <linux/dcache.h>
#include <linux/cred.h>
#include <linux/uuid.h>
+#include <linux/of.h>
#include <net/addrconf.h>
#ifdef CONFIG_BLOCK
#include <linux/blkdev.h>
@@ -1470,6 +1471,126 @@
return format_flags(buf, end, flags, names);
}
+static const char *device_node_name_for_depth(const struct device_node *np, int depth)
+{
+ for ( ; np && depth; depth--)
+ np = np->parent;
+
+ return kbasename(np->full_name);
+}
+
+static noinline_for_stack
+char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
+{
+ int depth;
+ const struct device_node *parent = np->parent;
+ static const struct printf_spec strspec = {
+ .field_width = -1,
+ .precision = -1,
+ };
+
+ /* special case for root node */
+ if (!parent)
+ return string(buf, end, "/", strspec);
+
+ for (depth = 0; parent->parent; depth++)
+ parent = parent->parent;
+
+ for ( ; depth >= 0; depth--) {
+ buf = string(buf, end, "/", strspec);
+ buf = string(buf, end, device_node_name_for_depth(np, depth),
+ strspec);
+ }
+ return buf;
+}
+
+static noinline_for_stack
+char *device_node_string(char *buf, char *end, struct device_node *dn,
+ struct printf_spec spec, const char *fmt)
+{
+ char tbuf[sizeof("xxxx") + 1];
+ const char *p;
+ int ret;
+ char *buf_start = buf;
+ struct property *prop;
+ bool has_mult, pass;
+ static const struct printf_spec num_spec = {
+ .flags = SMALL,
+ .field_width = -1,
+ .precision = -1,
+ .base = 10,
+ };
+
+ struct printf_spec str_spec = spec;
+ str_spec.field_width = -1;
+
+ if (!IS_ENABLED(CONFIG_OF))
+ return string(buf, end, "(!OF)", spec);
+
+ if ((unsigned long)dn < PAGE_SIZE)
+ return string(buf, end, "(null)", spec);
+
+ /* simple case without anything any more format specifiers */
+ fmt++;
+ if (fmt[0] == '\0' || strcspn(fmt,"fnpPFcC") > 0)
+ fmt = "f";
+
+ for (pass = false; strspn(fmt,"fnpPFcC"); fmt++, pass = true) {
+ if (pass) {
+ if (buf < end)
+ *buf = ':';
+ buf++;
+ }
+
+ switch (*fmt) {
+ case 'f': /* full_name */
+ buf = device_node_gen_full_name(dn, buf, end);
+ break;
+ case 'n': /* name */
+ buf = string(buf, end, dn->name, str_spec);
+ break;
+ case 'p': /* phandle */
+ buf = number(buf, end, (unsigned int)dn->phandle, num_spec);
+ break;
+ case 'P': /* path-spec */
+ p = kbasename(of_node_full_name(dn));
+ if (!p[1])
+ p = "/";
+ buf = string(buf, end, p, str_spec);
+ break;
+ case 'F': /* flags */
+ tbuf[0] = of_node_check_flag(dn, OF_DYNAMIC) ? 'D' : '-';
+ tbuf[1] = of_node_check_flag(dn, OF_DETACHED) ? 'd' : '-';
+ tbuf[2] = of_node_check_flag(dn, OF_POPULATED) ? 'P' : '-';
+ tbuf[3] = of_node_check_flag(dn, OF_POPULATED_BUS) ? 'B' : '-';
+ tbuf[4] = 0;
+ buf = string(buf, end, tbuf, str_spec);
+ break;
+ case 'c': /* major compatible string */
+ ret = of_property_read_string(dn, "compatible", &p);
+ if (!ret)
+ buf = string(buf, end, p, str_spec);
+ break;
+ case 'C': /* full compatible string */
+ has_mult = false;
+ of_property_for_each_string(dn, "compatible", prop, p) {
+ if (has_mult)
+ buf = string(buf, end, ",", str_spec);
+ buf = string(buf, end, "\"", str_spec);
+ buf = string(buf, end, p, str_spec);
+ buf = string(buf, end, "\"", str_spec);
+
+ has_mult = true;
+ }
+ break;
+ default:
+ break;
+ }
+ }
+
+ return widen_string(buf, buf - buf_start, end, spec);
+}
+
int kptr_restrict __read_mostly;
/*
@@ -1566,6 +1687,16 @@
* p page flags (see struct page) given as pointer to unsigned long
* g gfp flags (GFP_* and __GFP_*) given as pointer to gfp_t
* v vma flags (VM_*) given as pointer to unsigned long
+ * - 'O' For a kobject based struct. Must be one of the following:
+ * - 'OF[fnpPcCF]' For a device tree object
+ * Without any optional arguments prints the full_name
+ * f device node full_name
+ * n device node name
+ * p device node phandle
+ * P device node path spec (name + @unit)
+ * F device node flags
+ * c major compatible string
+ * C full compatible string
*
* ** Please update also Documentation/printk-formats.txt when making changes **
*
@@ -1721,6 +1852,11 @@
case 'G':
return flags_string(buf, end, ptr, fmt);
+ case 'O':
+ switch (fmt[1]) {
+ case 'F':
+ return device_node_string(buf, end, ptr, spec, fmt + 1);
+ }
}
spec.flags |= SMALL;
if (spec.field_width == -1) {