Commit ce4fecf1 authored by Pantelis Antoniou's avatar Pantelis Antoniou Committed by Rob Herring

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: default avatarPantelis Antoniou <pantelis.antoniou@konsulko.com>
Acked-by: default avatarJoe Perches <joe@perches.com>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
parent 27497e11
......@@ -275,6 +275,42 @@ struct va_format:
Passed by reference.
kobjects:
%pO
Base specifier for kobject based structs. Must be followed with
character for specific type of kobject as listed below:
Device tree nodes:
%pOF[fnpPcCF]
For printing device tree nodes. The optional arguments are:
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
Without any arguments prints full_name (same as %pOFf)
The separator when using multiple arguments is ':'
Examples:
%pOF /foo/bar@0 - Node full name
%pOFf /foo/bar@0 - Same as above
%pOFfp /foo/bar@0:10 - Node full name + phandle
%pOFfcF /foo/bar@0:foo,device:--P- - Node full name +
major compatible string +
node flags
D - dynamic
d - detached
P - Populated
B - Populated bus
Passed by reference.
struct clk:
%pC pll1
......
......@@ -26,7 +26,9 @@ test-device@1 {
#size-cells = <0>;
dev@100 {
compatible = "test-sub-device";
compatible = "test-sub-device",
"test-compat2",
"test-compat3";
reg = <0x100>;
};
};
......
......@@ -239,6 +239,63 @@ static void __init of_unittest_check_tree_linkage(void)
pr_debug("allnodes list size (%i); sibling lists size (%i)\n", allnode_count, child_count);
}
static void __init of_unittest_printf_one(struct device_node *np, const char *fmt,
const char *expected)
{
unsigned char buf[strlen(expected)+10];
int size, i;
/* Baseline; check conversion with a large size limit */
memset(buf, 0xff, sizeof(buf));
size = snprintf(buf, sizeof(buf) - 2, fmt, np);
/* use strcmp() instead of strncmp() here to be absolutely sure strings match */
unittest((strcmp(buf, expected) == 0) && (buf[size+1] == 0xff),
"sprintf failed; fmt='%s' expected='%s' rslt='%s'\n",
fmt, expected, buf);
/* Make sure length limits work */
size++;
for (i = 0; i < 2; i++, size--) {
/* Clear the buffer, and make sure it works correctly still */
memset(buf, 0xff, sizeof(buf));
snprintf(buf, size+1, fmt, np);
unittest(strncmp(buf, expected, size) == 0 && (buf[size+1] == 0xff),
"snprintf failed; size=%i fmt='%s' expected='%s' rslt='%s'\n",
size, fmt, expected, buf);
}
}
static void __init of_unittest_printf(void)
{
struct device_node *np;
const char *full_name = "/testcase-data/platform-tests/test-device@1/dev@100";
char phandle_str[16] = "";
np = of_find_node_by_path(full_name);
if (!np) {
unittest(np, "testcase data missing\n");
return;
}
num_to_str(phandle_str, sizeof(phandle_str), np->phandle);
of_unittest_printf_one(np, "%pOF", full_name);
of_unittest_printf_one(np, "%pOFf", full_name);
of_unittest_printf_one(np, "%pOFp", phandle_str);
of_unittest_printf_one(np, "%pOFP", "dev@100");
of_unittest_printf_one(np, "ABC %pOFP ABC", "ABC dev@100 ABC");
of_unittest_printf_one(np, "%10pOFP", " dev@100");
of_unittest_printf_one(np, "%-10pOFP", "dev@100 ");
of_unittest_printf_one(of_root, "%pOFP", "/");
of_unittest_printf_one(np, "%pOFF", "----");
of_unittest_printf_one(np, "%pOFPF", "dev@100:----");
of_unittest_printf_one(np, "%pOFPFPc", "dev@100:----:dev@100:test-sub-device");
of_unittest_printf_one(np, "%pOFc", "test-sub-device");
of_unittest_printf_one(np, "%pOFC",
"\"test-sub-device\",\"test-compat2\",\"test-compat3\"");
}
struct node_hash {
struct hlist_node node;
struct device_node *np;
......@@ -2269,6 +2326,7 @@ static int __init of_unittest(void)
of_unittest_find_node_by_name();
of_unittest_dynamic();
of_unittest_parse_phandle_with_args();
of_unittest_printf();
of_unittest_property_string();
of_unittest_property_copy();
of_unittest_changeset();
......
......@@ -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 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
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 @@ int kptr_restrict __read_mostly;
* 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 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
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) {
......
......@@ -5709,7 +5709,7 @@ sub process {
for (my $count = $linenr; $count <= $lc; $count++) {
my $fmt = get_quoted_string($lines[$count - 1], raw_line($count, 0));
$fmt =~ s/%%//g;
if ($fmt =~ /(\%[\*\d\.]*p(?![\WFfSsBKRraEhMmIiUDdgVCbGN]).)/) {
if ($fmt =~ /(\%[\*\d\.]*p(?![\WFfSsBKRraEhMmIiUDdgVCbGNO]).)/) {
$bad_extension = $1;
last;
}
......
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