[PATCH 0/4] DT printf format specifiers

[PATCH 0/4] DT printf format specifiers

[Rob Herring]

This resurrects an old patch[1] from Pantelis adding printf format 
specifiers for DT nodes. The previous versions didn't get applied after 
debate about the what character(s) to use. Grant suggested %pO for 
base kobject and %pOF for struct device_node. Everyone agreed, but no 
new version was posted.

I ended up re-writing the core implementation to be more inline with how 
other format specifiers are written which allowed removing #define code 
fragments. The other 3 patches convert the core DT code to use %pOF and 
prepare for changing device_node.full_name to stop storing the full path 
for every node.

My plan is to merge this series for v4.13 and post follow-up patches to 
convert all arches and subsystems to %pOF for v4.14. The full series is 
available here[2]. I tested this on QEMU running the DT unittests.

Rob

[1] https://patchwork.kernel.org/patch/6127521/
[2] git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git dt-printf

Pantelis Antoniou (1):
  of: Custom printk format specifier for device node

Rob Herring (3):
  of: use kbasename instead of open coding
  of: find_node_by_full_name rewrite to compare each level
  of: Convert to using %pOF instead of full_name

 Documentation/printk-formats.txt |  31 +++++++++
 drivers/of/address.c             |  21 +++---
 drivers/of/base.c                |  76 ++++++++++++----------
 drivers/of/device.c              |   2 +-
 drivers/of/dynamic.c             |  33 +++++-----
 drivers/of/irq.c                 |  10 +--
 drivers/of/of_mdio.c             |  10 +--
 drivers/of/of_pci.c              |  29 ++++-----
 drivers/of/of_private.h          |   3 +
 drivers/of/overlay.c             |  21 +++---
 drivers/of/platform.c            |  34 +++++-----
 drivers/of/resolver.c            |  34 ++--------
 drivers/of/unittest.c            |  66 +++++++++++--------
 lib/vsprintf.c                   | 135 ++++++++++++++++++++++++++++++++++++++-
 scripts/checkpatch.pl            |   2 +-
 15 files changed, 331 insertions(+), 176 deletions(-)

-- 
2.11.0

[PATCH 1/4] of: use kbasename instead of open coding

[Rob Herring]

Several places in DT code open code the equivalent of kbasename.
Replace them.

The behavior for root nodes in node_name_cmp will be slightly different.
Instead of comparing "/", "" will be compared. The comparison will be
the same.

Signed-off-by: Rob Herring <robh@kernel.org>
---
 drivers/of/base.c     | 5 +----
 drivers/of/platform.c | 2 +-
 drivers/of/resolver.c | 4 ++--
 3 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 28d5f53bc631..054159ccd5f8 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -773,10 +773,7 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent,
 		return NULL;
 
 	__for_each_child_of_node(parent, child) {
-		const char *name = strrchr(child->full_name, '/');
-		if (WARN(!name, "malformed device_node %s\n", child->full_name))
-			continue;
-		name++;
+		const char *name = kbasename(child->full_name);
 		if (strncmp(path, name, len) == 0 && (strlen(name) == len))
 			return child;
 	}
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 71fecc2debfc..8f73413fa243 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -99,7 +99,7 @@ static void of_device_make_bus_id(struct device *dev)
 
 		/* format arguments only used if dev_name() resolves to NULL */
 		dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
-			     strrchr(node->full_name, '/') + 1, dev_name(dev));
+			     kbasename(node->full_name), dev_name(dev));
 		node = node->parent;
 	}
 }
diff --git a/drivers/of/resolver.c b/drivers/of/resolver.c
index 771f4844c781..63626d7d9adb 100644
--- a/drivers/of/resolver.c
+++ b/drivers/of/resolver.c
@@ -165,8 +165,8 @@ static int update_usages_of_a_phandle_reference(struct device_node *overlay,
 static int node_name_cmp(const struct device_node *dn1,
 		const struct device_node *dn2)
 {
-	const char *n1 = strrchr(dn1->full_name, '/') ? : "/";
-	const char *n2 = strrchr(dn2->full_name, '/') ? : "/";
+	const char *n1 = kbasename(dn1->full_name);
+	const char *n2 = kbasename(dn2->full_name);
 
 	return of_node_cmp(n1, n2);
 }
-- 
2.11.0

[PATCH 2/4] of: find_node_by_full_name rewrite to compare each level

[Rob Herring]

find_node_by_full_name() does the same thing as of_find_node_by_path(),
but takes no locks and doesn't work on aliases. Refactor
of_find_node_opts_by_path() into __of_find_node_by_full_path() and
replace find_node_by_full_name() with it.

Signed-off-by: Rob Herring <robh@kernel.org>
---
 drivers/of/base.c       | 29 +++++++++++++++++++----------
 drivers/of/of_private.h |  3 +++
 drivers/of/resolver.c   | 30 +++---------------------------
 3 files changed, 25 insertions(+), 37 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 054159ccd5f8..02be991a29c5 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -780,6 +780,24 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent,
 	return NULL;
 }
 
+struct device_node *__of_find_node_by_full_path(struct device_node *node,
+						const char *path)
+{
+	const char *separator = strchr(path, ':');
+
+	while (node && *path == '/') {
+		struct device_node *tmp = node;
+
+		path++; /* Increment past '/' delimiter */
+		node = __of_find_node_by_path(node, path);
+		of_node_put(tmp);
+		path = strchrnul(path, '/');
+		if (separator && separator < path)
+			break;
+	}
+	return node;
+}
+
 /**
  *	of_find_node_opts_by_path - Find a node matching a full OF path
  *	@path: Either the full path to match, or if the path does not
@@ -839,16 +857,7 @@ struct device_node *of_find_node_opts_by_path(const char *path, const char **opt
 	raw_spin_lock_irqsave(&devtree_lock, flags);
 	if (!np)
 		np = of_node_get(of_root);
-	while (np && *path == '/') {
-		struct device_node *tmp = np;
-
-		path++; /* Increment past '/' delimiter */
-		np = __of_find_node_by_path(np, path);
-		of_node_put(tmp);
-		path = strchrnul(path, '/');
-		if (separator && separator < path)
-			break;
-	}
+	np =__of_find_node_by_full_path(np, path);
 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 	return np;
 }
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index 4ebb0149d118..e7bbfa3e9632 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -77,6 +77,9 @@ extern void *__unflatten_device_tree(const void *blob,
 struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags);
 __printf(2, 3) struct device_node *__of_node_dup(const struct device_node *np, const char *fmt, ...);
 
+struct device_node *__of_find_node_by_full_path(struct device_node *node,
+						const char *path);
+
 extern const void *__of_get_property(const struct device_node *np,
 				     const char *name, int *lenp);
 extern int __of_add_property(struct device_node *np, struct property *prop);
diff --git a/drivers/of/resolver.c b/drivers/of/resolver.c
index 63626d7d9adb..b3f987c1301b 100644
--- a/drivers/of/resolver.c
+++ b/drivers/of/resolver.c
@@ -20,35 +20,11 @@
 #include <linux/errno.h>
 #include <linux/slab.h>
 
+#include "of_private.h"
+
 /* illegal phandle value (set when unresolved) */
 #define OF_PHANDLE_ILLEGAL	0xdeadbeef
 
-/**
- * Find a node with the give full name by recursively following any of
- * the child node links.
- */
-static struct device_node *find_node_by_full_name(struct device_node *node,
-		const char *full_name)
-{
-	struct device_node *child, *found;
-
-	if (!node)
-		return NULL;
-
-	if (!of_node_cmp(node->full_name, full_name))
-		return of_node_get(node);
-
-	for_each_child_of_node(node, child) {
-		found = find_node_by_full_name(child, full_name);
-		if (found != NULL) {
-			of_node_put(child);
-			return found;
-		}
-	}
-
-	return NULL;
-}
-
 static phandle live_tree_max_phandle(void)
 {
 	struct device_node *node;
@@ -138,7 +114,7 @@ static int update_usages_of_a_phandle_reference(struct device_node *overlay,
 		if (err)
 			goto err_fail;
 
-		refnode = find_node_by_full_name(overlay, node_path);
+		refnode = __of_find_node_by_full_path(overlay, node_path);
 		if (!refnode)
 			continue;
 
-- 
2.11.0

[PATCH 3/4] of: Custom printk format specifier for device node

[Rob Herring]

From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>

90% of the usage of device node's full_name is printing it out
in a kernel message. Preparing for the eventual delayed allocation
introduce a custom printk format specifier that is both more
compact and more pleasant to the eye.

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);

More fine-grained control of formatting includes printing the name,
flag, path-spec name, reference count 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.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Signed-off-by: Rob Herring <robh@kernel.org>
---
 Documentation/printk-formats.txt |  31 +++++++++
 lib/vsprintf.c                   | 135 ++++++++++++++++++++++++++++++++++++++-
 scripts/checkpatch.pl            |   2 +-
 3 files changed, 166 insertions(+), 2 deletions(-)

diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 5962949944fd..07bc088ba5f5 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -275,6 +275,37 @@ struct va_format:
 
 	Passed by reference.
 
+Device tree nodes:
+
+	%pOF[fnpPcCFr]
+
+	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
+            r node reference count
+	Without any arguments prints full_name (same as %pOf)
+	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
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 2d41de3f98a1..80b3e237f8d1 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>
@@ -650,7 +651,7 @@ char *bdev_name(char *buf, char *end, struct block_device *bdev,
 		struct printf_spec spec, const char *fmt)
 {
 	struct gendisk *hd = bdev->bd_disk;
-	
+
 	buf = string(buf, end, hd->disk_name, spec);
 	if (bdev->bd_part->partno) {
 		if (isdigit(hd->disk_name[strlen(hd->disk_name)-1])) {
@@ -1470,6 +1471,123 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
 	return format_flags(buf, end, flags, names);
 }
 
+static noinline_for_stack
+char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
+{
+	int len, ret;
+
+	if (!np || !np->parent)
+		return buf;
+
+	buf = device_node_gen_full_name(np->parent, buf, end);
+
+	if (buf < end)
+		len = end - buf;
+	else
+		len = 0;
+	ret = snprintf(buf, len, "/%s", kbasename(np->full_name));
+	if (ret <= 0)
+		return buf;
+	else if (len == 0 || ret < len)
+		return buf + ret;
+	return buf + len;
+}
+
+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("xxxxxxxxxx") + 1];
+	const char *fmtp, *p;
+	int ret;
+	char *buf_start = buf;
+	struct property *prop;
+	bool has_mult, pass;
+	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 */
+	if (fmt[1] == '\0' || strcspn(fmt + 1,"fnpPFcCr") > 0)
+		fmt = "Ff";
+
+	for (fmtp = fmt + 1, pass = false; strspn(fmtp,"fnpPFcCr"); fmtp++, pass = true) {
+		if (pass && (*fmtp != 'f')) {
+			if (buf < end)
+				*buf = '|';
+			buf++;
+		}
+
+		switch (*fmtp) {
+		case 'f':	/* full_name */
+			if (pass) {
+				if (buf < end)
+					*buf = ':';
+				buf++;
+			}
+			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 */
+			buf = string(buf, end, kbasename(of_node_full_name(dn)), str_spec);
+			break;
+		case 'F':	/* flags */
+			snprintf(tbuf, sizeof(tbuf), "%c%c%c%c",
+				of_node_check_flag(dn, OF_DYNAMIC) ?
+					'D' : '-',
+				of_node_check_flag(dn, OF_DETACHED) ?
+					'd' : '-',
+				of_node_check_flag(dn, OF_POPULATED) ?
+					'P' : '-',
+				of_node_check_flag(dn,
+					OF_POPULATED_BUS) ?  'B' : '-');
+			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;
+		case 'r':	/* node reference count */
+			buf = number(buf, end, refcount_read(&dn->kobj.kref.refcount), num_spec);
+			break;
+		default:
+			break;
+		}
+	}
+
+	return widen_string(buf, buf - buf_start, end, spec);
+}
+
 int kptr_restrict __read_mostly;
 
 /*
@@ -1566,6 +1684,16 @@ 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
+ * - 'OF[fnpPcCFr]' For an DT device node
+ *                  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
+ *                  r node reference count
  *
  * ** Please update also Documentation/printk-formats.txt when making changes **
  *
@@ -1721,6 +1849,11 @@ 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) {
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 4b9569fa931b..411f2098fa6b 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -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;
 				}
-- 
2.11.0

[PATCH 4/4] of: Convert to using %pOF instead of full_name

[Rob Herring]

Now that we have a custom printf format specifier, convert users of
full_name to use %pOF instead. This is preparation to remove storing
of the full path string for each node.

Signed-off-by: Rob Herring <robh@kernel.org>
---
 drivers/of/address.c  | 21 ++++++++--------
 drivers/of/base.c     | 42 ++++++++++++++++----------------
 drivers/of/device.c   |  2 +-
 drivers/of/dynamic.c  | 33 +++++++++++++-------------
 drivers/of/irq.c      | 10 ++++----
 drivers/of/of_mdio.c  | 10 ++++----
 drivers/of/of_pci.c   | 29 +++++++++++-----------
 drivers/of/overlay.c  | 21 ++++++++--------
 drivers/of/platform.c | 32 ++++++++++++-------------
 drivers/of/unittest.c | 66 +++++++++++++++++++++++++++++----------------------
 10 files changed, 136 insertions(+), 130 deletions(-)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 72914cdfce2a..6cce3c750a8f 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -559,7 +559,7 @@ static u64 __of_translate_address(struct device_node *dev,
 	int na, ns, pna, pns;
 	u64 result = OF_BAD_ADDR;
 
-	pr_debug("** translation for device %s **\n", of_node_full_name(dev));
+	pr_debug("** translation for device %pOF **\n", dev);
 
 	/* Increase refcount at current level */
 	of_node_get(dev);
@@ -573,13 +573,13 @@ static u64 __of_translate_address(struct device_node *dev,
 	/* Count address cells & copy address locally */
 	bus->count_cells(dev, &na, &ns);
 	if (!OF_CHECK_COUNTS(na, ns)) {
-		pr_debug("Bad cell count for %s\n", of_node_full_name(dev));
+		pr_debug("Bad cell count for %pOF\n", dev);
 		goto bail;
 	}
 	memcpy(addr, in_addr, na * 4);
 
-	pr_debug("bus is %s (na=%d, ns=%d) on %s\n",
-	    bus->name, na, ns, of_node_full_name(parent));
+	pr_debug("bus is %s (na=%d, ns=%d) on %pOF\n",
+	    bus->name, na, ns, parent);
 	of_dump_addr("translating address:", addr, na);
 
 	/* Translate */
@@ -600,13 +600,12 @@ static u64 __of_translate_address(struct device_node *dev,
 		pbus = of_match_bus(parent);
 		pbus->count_cells(dev, &pna, &pns);
 		if (!OF_CHECK_COUNTS(pna, pns)) {
-			pr_err("Bad cell count for %s\n",
-			       of_node_full_name(dev));
+			pr_err("Bad cell count for %pOF\n", dev);
 			break;
 		}
 
-		pr_debug("parent bus is %s (na=%d, ns=%d) on %s\n",
-		    pbus->name, pna, pns, of_node_full_name(parent));
+		pr_debug("parent bus is %s (na=%d, ns=%d) on %pOF\n",
+		    pbus->name, pna, pns, parent);
 
 		/* Apply bus translation */
 		if (of_translate_one(dev, bus, pbus, addr, na, ns, pna, rprop))
@@ -855,7 +854,7 @@ int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *siz
 	}
 
 	if (!ranges) {
-		pr_debug("no dma-ranges found for node(%s)\n", np->full_name);
+		pr_debug("no dma-ranges found for node(%pOF)\n", np);
 		ret = -ENODEV;
 		goto out;
 	}
@@ -872,8 +871,8 @@ int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *siz
 	dmaaddr = of_read_number(ranges, naddr);
 	*paddr = of_translate_dma_address(np, ranges);
 	if (*paddr == OF_BAD_ADDR) {
-		pr_err("translation of DMA address(%pad) to CPU address failed node(%s)\n",
-		       dma_addr, np->full_name);
+		pr_err("translation of DMA address(%pad) to CPU address failed node(%pOF)\n",
+		       dma_addr, np);
 		ret = -EINVAL;
 		goto out;
 	}
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 02be991a29c5..bbbaf1d080c2 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -160,7 +160,7 @@ int __of_add_property_sysfs(struct device_node *np, struct property *pp)
 	pp->attr.read = of_node_property_read;
 
 	rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
-	WARN(rc, "error adding attribute %s to node %s\n", pp->name, np->full_name);
+	WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
 	return rc;
 }
 
@@ -1142,8 +1142,8 @@ int of_property_count_elems_of_size(const struct device_node *np,
 		return -ENODATA;
 
 	if (prop->length % elem_size != 0) {
-		pr_err("size of %s in node %s is not a multiple of %d\n",
-		       propname, np->full_name, elem_size);
+		pr_err("size of %s in node %pOF is not a multiple of %d\n",
+		       propname, np, elem_size);
 		return -EINVAL;
 	}
 
@@ -1574,7 +1574,7 @@ EXPORT_SYMBOL_GPL(of_property_read_string_helper);
 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
 {
 	int i;
-	printk("%s %s", msg, of_node_full_name(args->np));
+	printk("%s %pOF", msg, args->np);
 	for (i = 0; i < args->args_count; i++) {
 		const char delim = i ? ',' : ':';
 
@@ -1635,17 +1635,17 @@ int of_phandle_iterator_next(struct of_phandle_iterator *it)
 
 		if (it->cells_name) {
 			if (!it->node) {
-				pr_err("%s: could not find phandle\n",
-				       it->parent->full_name);
+				pr_err("%pOF: could not find phandle\n",
+				       it->parent);
 				goto err;
 			}
 
 			if (of_property_read_u32(it->node, it->cells_name,
 						 &count)) {
-				pr_err("%s: could not get %s for %s\n",
-				       it->parent->full_name,
+				pr_err("%pOF: could not get %s for %pOF\n",
+				       it->parent,
 				       it->cells_name,
-				       it->node->full_name);
+				       it->node);
 				goto err;
 			}
 		} else {
@@ -1657,8 +1657,8 @@ int of_phandle_iterator_next(struct of_phandle_iterator *it)
 		 * property data length
 		 */
 		if (it->cur + count > it->list_end) {
-			pr_err("%s: arguments longer than property\n",
-			       it->parent->full_name);
+			pr_err("%pOF: arguments longer than property\n",
+			       it->parent);
 			goto err;
 		}
 	}
@@ -2089,8 +2089,8 @@ static void of_alias_add(struct alias_prop *ap, struct device_node *np,
 	strncpy(ap->stem, stem, stem_len);
 	ap->stem[stem_len] = 0;
 	list_add_tail(&ap->link, &aliases_lookup);
-	pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
-		 ap->alias, ap->stem, ap->id, of_node_full_name(np));
+	pr_debug("adding DT alias:%s: stem=%s id=%i node=%pOF\n",
+		 ap->alias, ap->stem, ap->id, np);
 }
 
 /**
@@ -2344,8 +2344,8 @@ int of_graph_parse_endpoint(const struct device_node *node,
 {
 	struct device_node *port_node = of_get_parent(node);
 
-	WARN_ONCE(!port_node, "%s(): endpoint %s has no parent node\n",
-		  __func__, node->full_name);
+	WARN_ONCE(!port_node, "%s(): endpoint %pOF has no parent node\n",
+		  __func__, node);
 
 	memset(endpoint, 0, sizeof(*endpoint));
 
@@ -2428,14 +2428,14 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 		of_node_put(node);
 
 		if (!port) {
-			pr_err("graph: no port node found in %s\n",
-			       parent->full_name);
+			pr_err("graph: no port node found in %pOF\n",
+			       parent);
 			return NULL;
 		}
 	} else {
 		port = of_get_parent(prev);
-		if (WARN_ONCE(!port, "%s(): endpoint %s has no parent node\n",
-			      __func__, prev->full_name))
+		if (WARN_ONCE(!port, "%s(): endpoint %pOF has no parent node\n",
+			      __func__, prev))
 			return NULL;
 	}
 
@@ -2551,8 +2551,8 @@ struct device_node *of_graph_get_remote_node(const struct device_node *node,
 
 	endpoint_node = of_graph_get_endpoint_by_regs(node, port, endpoint);
 	if (!endpoint_node) {
-		pr_debug("no valid endpoint (%d, %d) for node %s\n",
-			 port, endpoint, node->full_name);
+		pr_debug("no valid endpoint (%d, %d) for node %pOF\n",
+			 port, endpoint, node);
 		return NULL;
 	}
 
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 9416d052cb89..cce2f48c92be 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -294,7 +294,7 @@ void of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 		return;
 
 	add_uevent_var(env, "OF_NAME=%s", dev->of_node->name);
-	add_uevent_var(env, "OF_FULLNAME=%s", dev->of_node->full_name);
+	add_uevent_var(env, "OF_FULLNAME=%pOF", dev->of_node);
 	if (dev->of_node->type && strcmp("<NULL>", dev->of_node->type) != 0)
 		add_uevent_var(env, "OF_TYPE=%s", dev->of_node->type);
 
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 888fdbc09992..4ee1bd9bd79c 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -98,14 +98,14 @@ int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
 	switch (action) {
 	case OF_RECONFIG_ATTACH_NODE:
 	case OF_RECONFIG_DETACH_NODE:
-		pr_debug("notify %-15s %s\n", action_names[action],
-			pr->dn->full_name);
+		pr_debug("notify %-15s %pOF\n", action_names[action],
+			pr->dn);
 		break;
 	case OF_RECONFIG_ADD_PROPERTY:
 	case OF_RECONFIG_REMOVE_PROPERTY:
 	case OF_RECONFIG_UPDATE_PROPERTY:
-		pr_debug("notify %-15s %s:%s\n", action_names[action],
-			pr->dn->full_name, pr->prop->name);
+		pr_debug("notify %-15s %pOF:%s\n", action_names[action],
+			pr->dn, pr->prop->name);
 		break;
 
 	}
@@ -328,11 +328,10 @@ void of_node_release(struct kobject *kobj)
 
 	/* We should never be releasing nodes that haven't been detached. */
 	if (!of_node_check_flag(node, OF_DETACHED)) {
-		pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
+		pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
 		dump_stack();
 		return;
 	}
-
 	if (!of_node_check_flag(node, OF_DYNAMIC))
 		return;
 
@@ -462,13 +461,13 @@ static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
 	case OF_RECONFIG_ADD_PROPERTY:
 	case OF_RECONFIG_REMOVE_PROPERTY:
 	case OF_RECONFIG_UPDATE_PROPERTY:
-		pr_debug("cset<%p> %-15s %s/%s\n", ce, action_names[ce->action],
-			ce->np->full_name, ce->prop->name);
+		pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
+			ce->np, ce->prop->name);
 		break;
 	case OF_RECONFIG_ATTACH_NODE:
 	case OF_RECONFIG_DETACH_NODE:
-		pr_debug("cset<%p> %-15s %s\n", ce, action_names[ce->action],
-			ce->np->full_name);
+		pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
+			ce->np);
 		break;
 	}
 }
@@ -539,7 +538,7 @@ static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool reve
 	}
 
 	if (ret)
-		pr_err("changeset notifier error @%s\n", ce->np->full_name);
+		pr_err("changeset notifier error @%pOF\n", ce->np);
 }
 
 static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
@@ -570,8 +569,8 @@ static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
 
 		ret = __of_add_property(ce->np, ce->prop);
 		if (ret) {
-			pr_err("changeset: add_property failed @%s/%s\n",
-				ce->np->full_name,
+			pr_err("changeset: add_property failed @%pOF/%s\n",
+				ce->np,
 				ce->prop->name);
 			break;
 		}
@@ -579,8 +578,8 @@ static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
 	case OF_RECONFIG_REMOVE_PROPERTY:
 		ret = __of_remove_property(ce->np, ce->prop);
 		if (ret) {
-			pr_err("changeset: remove_property failed @%s/%s\n",
-				ce->np->full_name,
+			pr_err("changeset: remove_property failed @%pOF/%s\n",
+				ce->np,
 				ce->prop->name);
 			break;
 		}
@@ -598,8 +597,8 @@ static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
 
 		ret = __of_update_property(ce->np, ce->prop, &old_prop);
 		if (ret) {
-			pr_err("changeset: update_property failed @%s/%s\n",
-				ce->np->full_name,
+			pr_err("changeset: update_property failed @%pOF/%s\n",
+				ce->np,
 				ce->prop->name);
 			break;
 		}
diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 6ce72aa65425..9c4b32522bc2 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -131,7 +131,7 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
 		goto fail;
 	}
 
-	pr_debug("of_irq_parse_raw: ipar=%s, size=%d\n", of_node_full_name(ipar), intsize);
+	pr_debug("of_irq_parse_raw: ipar=%pOF, size=%d\n", ipar, intsize);
 
 	if (out_irq->args_count != intsize)
 		goto fail;
@@ -269,7 +269,7 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
 	skiplevel:
 		/* Iterate again with new parent */
 		out_irq->np = newpar;
-		pr_debug(" -> new parent: %s\n", of_node_full_name(newpar));
+		pr_debug(" -> new parent: %pOF\n", newpar);
 		of_node_put(ipar);
 		ipar = newpar;
 		newpar = NULL;
@@ -301,7 +301,7 @@ int of_irq_parse_one(struct device_node *device, int index, struct of_phandle_ar
 	u32 intsize, intlen;
 	int i, res;
 
-	pr_debug("of_irq_parse_one: dev=%s, index=%d\n", of_node_full_name(device), index);
+	pr_debug("of_irq_parse_one: dev=%pOF, index=%d\n", device, index);
 
 	/* OldWorld mac stuff is "special", handle out of line */
 	if (of_irq_workarounds & OF_IMAP_OLDWORLD_MAC)
@@ -555,8 +555,8 @@ void __init of_irq_init(const struct of_device_id *matches)
 
 			of_node_set_flag(desc->dev, OF_POPULATED);
 
-			pr_debug("of_irq_init: init %s (%p), parent %p\n",
-				 desc->dev->full_name,
+			pr_debug("of_irq_init: init %pOF (%p), parent %p\n",
+				 desc->dev,
 				 desc->dev, desc->interrupt_parent);
 			ret = desc->irq_init_cb(desc->dev,
 						desc->interrupt_parent);
diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
index 7e4c80f9b6cd..f0a32be9cc61 100644
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -126,14 +126,14 @@ int of_mdio_parse_addr(struct device *dev, const struct device_node *np)
 
 	ret = of_property_read_u32(np, "reg", &addr);
 	if (ret < 0) {
-		dev_err(dev, "%s has invalid PHY address\n", np->full_name);
+		dev_err(dev, "%pOF has invalid PHY address\n", np);
 		return ret;
 	}
 
 	/* A PHY must have a reg property in the range [0-31] */
 	if (addr >= PHY_MAX_ADDR) {
-		dev_err(dev, "%s PHY address %i is too large\n",
-			np->full_name, addr);
+		dev_err(dev, "%pOF PHY address %i is too large\n",
+			np, addr);
 		return -EINVAL;
 	}
 
@@ -188,8 +188,8 @@ static bool of_mdiobus_child_is_phy(struct device_node *child)
 
 	if (of_match_node(whitelist_phys, child)) {
 		pr_warn(FW_WARN
-			"%s: Whitelisted compatible string. Please remove\n",
-			child->full_name);
+			"%pOF: Whitelisted compatible string. Please remove\n",
+			child);
 		return true;
 	}
 
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index c9d4d3a7b0fe..3d4cb7090878 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -204,15 +204,15 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 	if (!bus_range)
 		return -ENOMEM;
 
-	pr_info("host bridge %s ranges:\n", dev->full_name);
+	pr_info("host bridge %pOF ranges:\n", dev);
 
 	err = of_pci_parse_bus_range(dev, bus_range);
 	if (err) {
 		bus_range->start = busno;
 		bus_range->end = bus_max;
 		bus_range->flags = IORESOURCE_BUS;
-		pr_info("  No bus range found for %s, using %pR\n",
-			dev->full_name, bus_range);
+		pr_info("  No bus range found for %pOF, using %pR\n",
+			dev, bus_range);
 	} else {
 		if (bus_range->end > bus_range->start + bus_max)
 			bus_range->end = bus_range->start + bus_max;
@@ -258,14 +258,14 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 
 		if (resource_type(res) == IORESOURCE_IO) {
 			if (!io_base) {
-				pr_err("I/O range found for %s. Please provide an io_base pointer to save CPU base address\n",
-					dev->full_name);
+				pr_err("I/O range found for %pOF. Please provide an io_base pointer to save CPU base address\n",
+					dev);
 				err = -EINVAL;
 				goto conversion_failed;
 			}
 			if (*io_base != (resource_size_t)OF_BAD_ADDR)
-				pr_warn("More than one I/O resource converted for %s. CPU base address for old range lost!\n",
-					dev->full_name);
+				pr_warn("More than one I/O resource converted for %pOF. CPU base address for old range lost!\n",
+					dev);
 			*io_base = range.cpu_addr;
 		}
 
@@ -325,7 +325,7 @@ int of_pci_map_rid(struct device_node *np, u32 rid,
 	}
 
 	if (!map_len || map_len % (4 * sizeof(*map))) {
-		pr_err("%s: Error: Bad %s length: %d\n", np->full_name,
+		pr_err("%pOF: Error: Bad %s length: %d\n", np,
 			map_name, map_len);
 		return -EINVAL;
 	}
@@ -349,8 +349,8 @@ int of_pci_map_rid(struct device_node *np, u32 rid,
 		u32 rid_len = be32_to_cpup(map + 3);
 
 		if (rid_base & ~map_mask) {
-			pr_err("%s: Invalid %s translation - %s-mask (0x%x) ignores rid-base (0x%x)\n",
-				np->full_name, map_name, map_name,
+			pr_err("%pOF: Invalid %s translation - %s-mask (0x%x) ignores rid-base (0x%x)\n",
+				np, map_name, map_name,
 				map_mask, rid_base);
 			return -EFAULT;
 		}
@@ -375,14 +375,13 @@ int of_pci_map_rid(struct device_node *np, u32 rid,
 		if (id_out)
 			*id_out = masked_rid - rid_base + out_base;
 
-		pr_debug("%s: %s, using mask %08x, rid-base: %08x, out-base: %08x, length: %08x, rid: %08x -> %08x\n",
-			np->full_name, map_name, map_mask, rid_base, out_base,
+		pr_debug("%pOF: %s, using mask %08x, rid-base: %08x, out-base: %08x, length: %08x, rid: %08x -> %08x\n",
+			np, map_name, map_mask, rid_base, out_base,
 			rid_len, rid, *id_out);
 		return 0;
 	}
 
-	pr_err("%s: Invalid %s translation - no match for rid 0x%x on %s\n",
-		np->full_name, map_name, rid,
-		target && *target ? (*target)->full_name : "any target");
+	pr_err("%pOF: Invalid %s translation - no match for rid 0x%x on %pOF\n",
+		np, map_name, rid, target && *target ? *target : NULL);
 	return -EFAULT;
 }
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 7827786718d8..5948eac07f34 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -137,7 +137,7 @@ static int of_overlay_apply_single_device_node(struct of_overlay *ov,
 		of_node_put(tchild);
 	} else {
 		/* create empty tree as a target */
-		tchild = __of_node_dup(child, "%s/%s", target->full_name, cname);
+		tchild = __of_node_dup(child, "%pOF/%s", target, cname);
 		if (!tchild)
 			return -ENOMEM;
 
@@ -173,8 +173,8 @@ static int of_overlay_apply_one(struct of_overlay *ov,
 	for_each_property_of_node(overlay, prop) {
 		ret = of_overlay_apply_single_property(ov, target, prop);
 		if (ret) {
-			pr_err("Failed to apply prop @%s/%s\n",
-			       target->full_name, prop->name);
+			pr_err("Failed to apply prop @%pOF/%s\n",
+			       target, prop->name);
 			return ret;
 		}
 	}
@@ -182,8 +182,8 @@ static int of_overlay_apply_one(struct of_overlay *ov,
 	for_each_child_of_node(overlay, child) {
 		ret = of_overlay_apply_single_device_node(ov, target, child);
 		if (ret != 0) {
-			pr_err("Failed to apply single node @%s/%s\n",
-			       target->full_name, child->name);
+			pr_err("Failed to apply single node @%pOF/%s\n",
+			       target, child->name);
 			of_node_put(child);
 			return ret;
 		}
@@ -211,7 +211,7 @@ static int of_overlay_apply(struct of_overlay *ov)
 
 		err = of_overlay_apply_one(ov, ovinfo->target, ovinfo->overlay);
 		if (err != 0) {
-			pr_err("apply failed '%s'\n", ovinfo->target->full_name);
+			pr_err("apply failed '%pOF'\n", ovinfo->target);
 			return err;
 		}
 	}
@@ -396,8 +396,8 @@ int of_overlay_create(struct device_node *tree)
 	/* build the overlay info structures */
 	err = of_build_overlay_info(ov, tree);
 	if (err) {
-		pr_err("of_build_overlay_info() failed for tree@%s\n",
-		       tree->full_name);
+		pr_err("of_build_overlay_info() failed for tree@%pOF\n",
+		       tree);
 		goto err_free_idr;
 	}
 
@@ -476,9 +476,8 @@ static int overlay_is_topmost(struct of_overlay *ov, struct device_node *dn)
 		/* check against each subtree affected by this overlay */
 		list_for_each_entry(ce, &ovt->cset.entries, node) {
 			if (overlay_subtree_check(ce->np, dn)) {
-				pr_err("%s: #%d clashes #%d @%s\n",
-					__func__, ov->id, ovt->id,
-					dn->full_name);
+				pr_err("%s: #%d clashes #%d @%pOF\n",
+					__func__, ov->id, ovt->id, dn);
 				return 0;
 			}
 		}
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 8f73413fa243..09045265b1b9 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -228,7 +228,7 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
 	const void *prop;
 	int i, ret;
 
-	pr_debug("Creating amba device %s\n", node->full_name);
+	pr_debug("Creating amba device %pOF\n", node);
 
 	if (!of_device_is_available(node) ||
 	    of_node_test_and_set_flag(node, OF_POPULATED))
@@ -259,15 +259,15 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
 
 	ret = of_address_to_resource(node, 0, &dev->res);
 	if (ret) {
-		pr_err("amba: of_address_to_resource() failed (%d) for %s\n",
-		       ret, node->full_name);
+		pr_err("amba: of_address_to_resource() failed (%d) for %pOF\n",
+		       ret, node);
 		goto err_free;
 	}
 
 	ret = amba_device_add(dev, &iomem_resource);
 	if (ret) {
-		pr_err("amba_device_add() failed (%d) for %s\n",
-		       ret, node->full_name);
+		pr_err("amba_device_add() failed (%d) for %pOF\n",
+		       ret, node);
 		goto err_free;
 	}
 
@@ -310,7 +310,7 @@ static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *l
 		if (!of_address_to_resource(np, 0, &res))
 			if (res.start != auxdata->phys_addr)
 				continue;
-		pr_debug("%s: devname=%s\n", np->full_name, auxdata->name);
+		pr_debug("%pOF: devname=%s\n", np, auxdata->name);
 		return auxdata;
 	}
 
@@ -323,7 +323,7 @@ static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *l
 		if (!of_device_is_compatible(np, auxdata->compatible))
 			continue;
 		if (!auxdata->phys_addr && !auxdata->name) {
-			pr_debug("%s: compatible match\n", np->full_name);
+			pr_debug("%pOF: compatible match\n", np);
 			return auxdata;
 		}
 	}
@@ -356,14 +356,14 @@ static int of_platform_bus_create(struct device_node *bus,
 
 	/* Make sure it has a compatible property */
 	if (strict && (!of_get_property(bus, "compatible", NULL))) {
-		pr_debug("%s() - skipping %s, no compatible prop\n",
-			 __func__, bus->full_name);
+		pr_debug("%s() - skipping %pOF, no compatible prop\n",
+			 __func__, bus);
 		return 0;
 	}
 
 	if (of_node_check_flag(bus, OF_POPULATED_BUS)) {
-		pr_debug("%s() - skipping %s, already populated\n",
-			__func__, bus->full_name);
+		pr_debug("%s() - skipping %pOF, already populated\n",
+			__func__, bus);
 		return 0;
 	}
 
@@ -387,7 +387,7 @@ static int of_platform_bus_create(struct device_node *bus,
 		return 0;
 
 	for_each_child_of_node(bus, child) {
-		pr_debug("   create child: %s\n", child->full_name);
+		pr_debug("   create child: %pOF\n", child);
 		rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
 		if (rc) {
 			of_node_put(child);
@@ -419,7 +419,7 @@ int of_platform_bus_probe(struct device_node *root,
 		return -EINVAL;
 
 	pr_debug("%s()\n", __func__);
-	pr_debug(" starting at: %s\n", root->full_name);
+	pr_debug(" starting at: %pOF\n", root);
 
 	/* Do a self check of bus type, if there's a match, create children */
 	if (of_match_node(matches, root)) {
@@ -471,7 +471,7 @@ int of_platform_populate(struct device_node *root,
 		return -EINVAL;
 
 	pr_debug("%s()\n", __func__);
-	pr_debug(" starting at: %s\n", root->full_name);
+	pr_debug(" starting at: %pOF\n", root);
 
 	for_each_child_of_node(root, child) {
 		rc = of_platform_bus_create(child, matches, lookup, parent, true);
@@ -659,8 +659,8 @@ static int of_platform_notify(struct notifier_block *nb,
 		of_dev_put(pdev_parent);
 
 		if (pdev == NULL) {
-			pr_err("%s: failed to create for '%s'\n",
-					__func__, rd->dn->full_name);
+			pr_err("%s: failed to create for '%pOF'\n",
+					__func__, rd->dn);
 			/* of_platform_device_create tosses the error code */
 			return notifier_from_errno(-EINVAL);
 		}
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 987a1530282a..038fec3e3463 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -46,46 +46,54 @@ static struct unittest_results {
 static void __init of_unittest_find_node_by_name(void)
 {
 	struct device_node *np;
-	const char *options;
+	const char *options, *name;
 
 	np = of_find_node_by_path("/testcase-data");
-	unittest(np && !strcmp("/testcase-data", np->full_name),
+	name = kasprintf(GFP_KERNEL, "%pOF", np);
+	unittest(np && !strcmp("/testcase-data", name),
 		"find /testcase-data failed\n");
 	of_node_put(np);
+	kfree(name);
 
 	/* Test if trailing '/' works */
 	np = of_find_node_by_path("/testcase-data/");
 	unittest(!np, "trailing '/' on /testcase-data/ should fail\n");
 
 	np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a");
-	unittest(np && !strcmp("/testcase-data/phandle-tests/consumer-a", np->full_name),
+	name = kasprintf(GFP_KERNEL, "%pOF", np);
+	unittest(np && !strcmp("/testcase-data/phandle-tests/consumer-a", name),
 		"find /testcase-data/phandle-tests/consumer-a failed\n");
 	of_node_put(np);
+	kfree(name);
 
 	np = of_find_node_by_path("testcase-alias");
-	unittest(np && !strcmp("/testcase-data", np->full_name),
+	name = kasprintf(GFP_KERNEL, "%pOF", np);
+	unittest(np && !strcmp("/testcase-data", name),
 		"find testcase-alias failed\n");
 	of_node_put(np);
+	kfree(name);
 
 	/* Test if trailing '/' works on aliases */
 	np = of_find_node_by_path("testcase-alias/");
 	unittest(!np, "trailing '/' on testcase-alias/ should fail\n");
 
 	np = of_find_node_by_path("testcase-alias/phandle-tests/consumer-a");
-	unittest(np && !strcmp("/testcase-data/phandle-tests/consumer-a", np->full_name),
+	name = kasprintf(GFP_KERNEL, "%pOF", np);
+	unittest(np && !strcmp("/testcase-data/phandle-tests/consumer-a", name),
 		"find testcase-alias/phandle-tests/consumer-a failed\n");
 	of_node_put(np);
+	kfree(name);
 
 	np = of_find_node_by_path("/testcase-data/missing-path");
-	unittest(!np, "non-existent path returned node %s\n", np->full_name);
+	unittest(!np, "non-existent path returned node %pOF\n", np);
 	of_node_put(np);
 
 	np = of_find_node_by_path("missing-alias");
-	unittest(!np, "non-existent alias returned node %s\n", np->full_name);
+	unittest(!np, "non-existent alias returned node %pOF\n", np);
 	of_node_put(np);
 
 	np = of_find_node_by_path("testcase-alias/missing-path");
-	unittest(!np, "non-existent alias with relative path returned node %s\n", np->full_name);
+	unittest(!np, "non-existent alias with relative path returned node %pOF\n", np);
 	of_node_put(np);
 
 	np = of_find_node_opts_by_path("/testcase-data:testoption", &options);
@@ -258,8 +266,8 @@ static void __init of_unittest_check_phandles(void)
 
 		hash_for_each_possible(phandle_ht, nh, node, np->phandle) {
 			if (nh->np->phandle == np->phandle) {
-				pr_info("Duplicate phandle! %i used by %s and %s\n",
-					np->phandle, nh->np->full_name, np->full_name);
+				pr_info("Duplicate phandle! %i used by %pOF and %pOF\n",
+					np->phandle, nh->np, np);
 				dup_count++;
 				break;
 			}
@@ -349,8 +357,8 @@ static void __init of_unittest_parse_phandle_with_args(void)
 			passed = false;
 		}
 
-		unittest(passed, "index %i - data error on node %s rc=%i\n",
-			 i, args.np->full_name, rc);
+		unittest(passed, "index %i - data error on node %pOF rc=%i\n",
+			 i, args.np, rc);
 	}
 
 	/* Check for missing list property */
@@ -533,7 +541,7 @@ static void __init of_unittest_changeset(void)
 
 	/* Make sure node names are constructed correctly */
 	unittest((np = of_find_node_by_path("/testcase-data/changeset/n2/n21")),
-		 "'%s' not added\n", n21->full_name);
+		 "'%pOF' not added\n", n21);
 	of_node_put(np);
 
 	unittest(!of_changeset_revert(&chgset), "revert failed\n");
@@ -564,8 +572,8 @@ static void __init of_unittest_parse_interrupts(void)
 		passed &= (args.args_count == 1);
 		passed &= (args.args[0] == (i + 1));
 
-		unittest(passed, "index %i - data error on node %s rc=%i\n",
-			 i, args.np->full_name, rc);
+		unittest(passed, "index %i - data error on node %pOF rc=%i\n",
+			 i, args.np, rc);
 	}
 	of_node_put(np);
 
@@ -610,8 +618,8 @@ static void __init of_unittest_parse_interrupts(void)
 		default:
 			passed = false;
 		}
-		unittest(passed, "index %i - data error on node %s rc=%i\n",
-			 i, args.np->full_name, rc);
+		unittest(passed, "index %i - data error on node %pOF rc=%i\n",
+			 i, args.np, rc);
 	}
 	of_node_put(np);
 }
@@ -680,8 +688,8 @@ static void __init of_unittest_parse_interrupts_extended(void)
 			passed = false;
 		}
 
-		unittest(passed, "index %i - data error on node %s rc=%i\n",
-			 i, args.np->full_name, rc);
+		unittest(passed, "index %i - data error on node %pOF rc=%i\n",
+			 i, args.np, rc);
 	}
 	of_node_put(np);
 }
@@ -861,7 +869,9 @@ static int attach_node_and_children(struct device_node *np)
 	struct device_node *next, *dup, *child;
 	unsigned long flags;
 
-	dup = of_find_node_by_path(np->full_name);
+	full_name = kasprintf(GFP_KERNEL, "%pOF", np);
+	dup = of_find_node_by_path(full_name);
+	kfree(full_name);
 	if (dup) {
 		update_node_properties(np, dup);
 		return 0;
@@ -966,7 +976,7 @@ static int unittest_probe(struct platform_device *pdev)
 
 	}
 
-	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
+	dev_dbg(dev, "%s for node @%pOF\n", __func__, np);
 
 	of_platform_populate(np, NULL, NULL, &pdev->dev);
 
@@ -978,7 +988,7 @@ static int unittest_remove(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 
-	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
+	dev_dbg(dev, "%s for node @%pOF\n", __func__, np);
 	return 0;
 }
 
@@ -1592,7 +1602,7 @@ static int unittest_i2c_bus_probe(struct platform_device *pdev)
 
 	}
 
-	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
+	dev_dbg(dev, "%s for node @%pOF\n", __func__, np);
 
 	std = devm_kzalloc(dev, sizeof(*std), GFP_KERNEL);
 	if (!std) {
@@ -1630,7 +1640,7 @@ static int unittest_i2c_bus_remove(struct platform_device *pdev)
 	struct device_node *np = dev->of_node;
 	struct unittest_i2c_bus_data *std = platform_get_drvdata(pdev);
 
-	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
+	dev_dbg(dev, "%s for node @%pOF\n", __func__, np);
 	i2c_del_adapter(&std->adap);
 
 	return 0;
@@ -1661,7 +1671,7 @@ static int unittest_i2c_dev_probe(struct i2c_client *client,
 		return -EINVAL;
 	}
 
-	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
+	dev_dbg(dev, "%s for node @%pOF\n", __func__, np);
 
 	return 0;
 };
@@ -1671,7 +1681,7 @@ static int unittest_i2c_dev_remove(struct i2c_client *client)
 	struct device *dev = &client->dev;
 	struct device_node *np = client->dev.of_node;
 
-	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
+	dev_dbg(dev, "%s for node @%pOF\n", __func__, np);
 	return 0;
 }
 
@@ -1706,7 +1716,7 @@ static int unittest_i2c_mux_probe(struct i2c_client *client,
 	struct i2c_mux_core *muxc;
 	u32 reg, max_reg;
 
-	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
+	dev_dbg(dev, "%s for node @%pOF\n", __func__, np);
 
 	if (!np) {
 		dev_err(dev, "No OF node\n");
@@ -1751,7 +1761,7 @@ static int unittest_i2c_mux_remove(struct i2c_client *client)
 	struct device_node *np = client->dev.of_node;
 	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 
-	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
+	dev_dbg(dev, "%s for node @%pOF\n", __func__, np);
 	i2c_mux_del_adapters(muxc);
 	return 0;
 }
-- 
2.11.0

Re: [PATCH 3/4] of: Custom printk format specifier for device node

[Joe Perches]

On Wed, 2017-06-14 at 15:30 -0500, Rob Herring wrote:
> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>

I think the commit subject is wrong.
It adds an "of" specific bit to vsprintf.c.
The subject should be
'vsprintf:  Add %p extension "%pO" for device tree'

> 90% of the usage of device node's full_name is printing it out
> in a kernel message. Preparing for the eventual delayed allocation
> introduce a custom printk format specifier that is both more
> compact and more pleasant to the eye.
> 
> 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);

Somehow I think this example is poor as node->full_name
is a pretty obvious to read use.  %pOF requires you to
look up or know what the output is going to be.

> More fine-grained control of formatting includes printing the name,
> flag, path-spec name, reference count 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.

Some comments about the code.

> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> []
> @@ -1470,6 +1471,123 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
>  	return format_flags(buf, end, flags, names);
>  }
>  
> +static noinline_for_stack
> +char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
> +{
> +	int len, ret;
> +
> +	if (!np || !np->parent)
> +		return buf;
> +
> +	buf = device_node_gen_full_name(np->parent, buf, end);

This is recursive.  How many levels of parents could there be?
Perhaps there should be a recursion limit.

> +
> +	if (buf < end)
> +		len = end - buf;
> +	else
> +		len = 0;
> +	ret = snprintf(buf, len, "/%s", kbasename(np->full_name));
> +	if (ret <= 0)
> +		return buf;
> +	else if (len == 0 || ret < len)
> +		return buf + ret;
> +	return buf + len;
> +}

Does this work with %p<len>OF for a right justified or padded
length string?  Perhaps widen_string should be added.

> +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("xxxxxxxxxx") + 1];
> +	const char *fmtp, *p;
> +	int ret;
> +	char *buf_start = buf;
> +	struct property *prop;
> +	bool has_mult, pass;
> +	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 */
> +	if (fmt[1] == '\0' || strcspn(fmt + 1,"fnpPFcCr") > 0)
> +		fmt = "Ff";
> +
> +	for (fmtp = fmt + 1, pass = false; strspn(fmtp,"fnpPFcCr"); fmtp++, pass = true) {

why not
	while (isalpha(*++fmt))
like ip6 or isalnum like FORMAT_TYPE_PTR uses?

> +		if (pass && (*fmtp != 'f')) {
> +			if (buf < end)
> +				*buf = '|';
> +			buf++;
> +		}
> +
> +		switch (*fmtp) {
> +		case 'f':	/* full_name */
> +			if (pass) {
> +				if (buf < end)
> +					*buf = ':';
> +				buf++;
> +			}
> +			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 */
> +			buf = string(buf, end, kbasename(of_node_full_name(dn)), str_spec);
> +			break;
> +		case 'F':	/* flags */
> +			snprintf(tbuf, sizeof(tbuf), "%c%c%c%c",
> +				of_node_check_flag(dn, OF_DYNAMIC) ?
> +					'D' : '-',
> +				of_node_check_flag(dn, OF_DETACHED) ?
> +					'd' : '-',
> +				of_node_check_flag(dn, OF_POPULATED) ?
> +					'P' : '-',
> +				of_node_check_flag(dn,
> +					OF_POPULATED_BUS) ?  'B' : '-');

I'd try to avoid all uses of snprintf as it's effectively
another fairly
large stack frame.

It's probably better to avoid more recursion stack depth use
and just use *buf++ as appropriate.

Re: [PATCH 4/4] of: Convert to using %pOF instead of full_name

[Joe Perches]

On Wed, 2017-06-14 at 15:30 -0500, Rob Herring wrote:
> Now that we have a custom printf format specifier, convert users of
> full_name to use %pOF instead. This is preparation to remove storing
> of the full path string for each node.

Well, a full_name removal makes my reply in 2/4 less sensible.
Maybe 2/4 should say that full_name is going away.

Re: [PATCH 3/4] of: Custom printk format specifier for device node

[Rob Herring]

On Wed, Jun 14, 2017 at 3:56 PM, Joe Perches <joe@perches.com> wrote:
> On Wed, 2017-06-14 at 15:30 -0500, Rob Herring wrote:
>> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
>
> I think the commit subject is wrong.
> It adds an "of" specific bit to vsprintf.c.
> The subject should be
> 'vsprintf:  Add %p extension "%pO" for device tree'

Okay, but it was good enough for the 2-3 versions Pantelis did before...

>> 90% of the usage of device node's full_name is printing it out
>> in a kernel message. Preparing for the eventual delayed allocation
>> introduce a custom printk format specifier that is both more
>> compact and more pleasant to the eye.
>>
>> 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);
>
> Somehow I think this example is poor as node->full_name
> is a pretty obvious to read use.  %pOF requires you to
> look up or know what the output is going to be.

So %pOFfullname? We've beat this one to death IMO.

>
>> More fine-grained control of formatting includes printing the name,
>> flag, path-spec name, reference count 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.
>
> Some comments about the code.
>
>> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
>> []
>> @@ -1470,6 +1471,123 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
>>       return format_flags(buf, end, flags, names);
>>  }
>>
>> +static noinline_for_stack
>> +char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
>> +{
>> +     int len, ret;
>> +
>> +     if (!np || !np->parent)
>> +             return buf;
>> +
>> +     buf = device_node_gen_full_name(np->parent, buf, end);
>
> This is recursive.  How many levels of parents could there be?
> Perhaps there should be a recursion limit.

2-6 I'd say is typical. The FDT unflattening code limits things to 64
(which is probably way more than needed).

I could re-write it to be non-recursive, but then I'll just have the
max sized array of pointers on the stack.

>
>> +
>> +     if (buf < end)
>> +             len = end - buf;
>> +     else
>> +             len = 0;
>> +     ret = snprintf(buf, len, "/%s", kbasename(np->full_name));

I can replace this one too with a strcat and save some stack space.

>> +     if (ret <= 0)
>> +             return buf;
>> +     else if (len == 0 || ret < len)
>> +             return buf + ret;
>> +     return buf + len;
>> +}
>
> Does this work with %p<len>OF for a right justified or padded
> length string?  Perhaps widen_string should be added.

widen_string is called at the end of device_node_string.

>> +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("xxxxxxxxxx") + 1];
>> +     const char *fmtp, *p;
>> +     int ret;
>> +     char *buf_start = buf;
>> +     struct property *prop;
>> +     bool has_mult, pass;
>> +     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 */
>> +     if (fmt[1] == '\0' || strcspn(fmt + 1,"fnpPFcCr") > 0)
>> +             fmt = "Ff";
>> +
>> +     for (fmtp = fmt + 1, pass = false; strspn(fmtp,"fnpPFcCr"); fmtp++, pass = true) {
>
> why not
>         while (isalpha(*++fmt))
> like ip6 or isalnum like FORMAT_TYPE_PTR uses?

Okay.

>
>> +             if (pass && (*fmtp != 'f')) {
>> +                     if (buf < end)
>> +                             *buf = '|';
>> +                     buf++;
>> +             }
>> +
>> +             switch (*fmtp) {
>> +             case 'f':       /* full_name */
>> +                     if (pass) {
>> +                             if (buf < end)
>> +                                     *buf = ':';
>> +                             buf++;
>> +                     }
>> +                     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 */
>> +                     buf = string(buf, end, kbasename(of_node_full_name(dn)), str_spec);
>> +                     break;
>> +             case 'F':       /* flags */
>> +                     snprintf(tbuf, sizeof(tbuf), "%c%c%c%c",
>> +                             of_node_check_flag(dn, OF_DYNAMIC) ?
>> +                                     'D' : '-',
>> +                             of_node_check_flag(dn, OF_DETACHED) ?
>> +                                     'd' : '-',
>> +                             of_node_check_flag(dn, OF_POPULATED) ?
>> +                                     'P' : '-',
>> +                             of_node_check_flag(dn,
>> +                                     OF_POPULATED_BUS) ?  'B' : '-');
>
> I'd try to avoid all uses of snprintf as it's effectively
> another fairly
> large stack frame.

Okay.

> It's probably better to avoid more recursion stack depth use
> and just use *buf++ as appropriate.

You can't use *buf++ as this code must work and increment buf even
when buf is NULL.

Rob

Re: [PATCH 3/4] of: Custom printk format specifier for device node

[Joe Perches]

On Thu, 2017-06-15 at 07:30 -0500, Rob Herring wrote:
> On Wed, Jun 14, 2017 at 3:56 PM, Joe Perches <joe@perches.com> wrote:
> > On Wed, 2017-06-14 at 15:30 -0500, Rob Herring wrote:
> > > From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> > 
> > I think the commit subject is wrong.
> > It adds an "of" specific bit to vsprintf.c.
> > The subject should be
> > 'vsprintf:  Add %p extension "%pO" for device tree'
> 
> Okay, but it was good enough for the 2-3 versions Pantelis did before...

Which were not applied.

> > > 90% of the usage of device node's full_name is printing it out
> > > in a kernel message. Preparing for the eventual delayed allocation

The "eventual delayed allocation" bit doesn't
mean anything to me.

> > > introduce a custom printk format specifier that is both more
> > > compact and more pleasant to the eye.
> > > 
> > > 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);
> > 
> > Somehow I think this example is poor as node->full_name
> > is a pretty obvious to read use.  %pOF requires you to
> > look up or know what the output is going to be.
> 
> So %pOFfullname? We've beat this one to death IMO.

I don't doubt the utility, just the example.
Just mention that full_name is going away.

> > > More fine-grained control of formatting includes printing the name,
> > > flag, path-spec name, reference count 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.
> > 
> > Some comments about the code.
> > 
> > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> > > []
> > > @@ -1470,6 +1471,123 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
> > >       return format_flags(buf, end, flags, names);
> > >  }
> > > 
> > > +static noinline_for_stack
> > > +char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
> > > +{
> > > +     int len, ret;
> > > +
> > > +     if (!np || !np->parent)
> > > +             return buf;
> > > +
> > > +     buf = device_node_gen_full_name(np->parent, buf, end);
> > 
> > This is recursive.  How many levels of parents could there be?
> > Perhaps there should be a recursion limit.
> 
> 2-6 I'd say is typical. The FDT unflattening code limits things to 64
> (which is probably way more than needed).
> 
> I could re-write it to be non-recursive, but then I'll just have the
> max sized array of pointers on the stack.

Which would be less stack than how many recursive calls?  5?

In any case, 64 * 8 for pointers or 5+ stack
frames is a fair amount of stack.

Maybe too much.

> > > +             case 'F':       /* flags */
> > > +                     snprintf(tbuf, sizeof(tbuf), "%c%c%c%c",
> > > +                             of_node_check_flag(dn, OF_DYNAMIC) ?
> > > +                                     'D' : '-',
> > > +                             of_node_check_flag(dn, OF_DETACHED) ?
> > > +                                     'd' : '-',
> > > +                             of_node_check_flag(dn, OF_POPULATED) ?
> > > +                                     'P' : '-',
> > > +                             of_node_check_flag(dn,
> > > +                                     OF_POPULATED_BUS) ?  'B' : '-');
> > 
> > I'd try to avoid all uses of snprintf as it's effectively
> > another fairly large stack frame.
> 
> Okay.
> 
> > It's probably better to avoid more recursion stack depth use
> > and just use *buf++ as appropriate.
> 
> You can't use *buf++ as this code must work and increment buf even
> when buf is NULL.

tbuf then.

Re: [PATCH 3/4] of: Custom printk format specifier for device node

[Rob Herring]

On Wed, Jun 14, 2017 at 01:56:48PM -0700, Joe Perches wrote:
> On Wed, 2017-06-14 at 15:30 -0500, Rob Herring wrote:
> > From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> 
> I think the commit subject is wrong.
> It adds an "of" specific bit to vsprintf.c.
> The subject should be
> 'vsprintf:  Add %p extension "%pO" for device tree'
> 
> > 90% of the usage of device node's full_name is printing it out
> > in a kernel message. Preparing for the eventual delayed allocation
> > introduce a custom printk format specifier that is both more
> > compact and more pleasant to the eye.
> > 
> > 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);
> 
> Somehow I think this example is poor as node->full_name
> is a pretty obvious to read use.  %pOF requires you to
> look up or know what the output is going to be.
> 
> > More fine-grained control of formatting includes printing the name,
> > flag, path-spec name, reference count 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.
> 
> Some comments about the code.
> 
> > diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> > []
> > @@ -1470,6 +1471,123 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
> >  	return format_flags(buf, end, flags, names);
> >  }
> >  
> > +static noinline_for_stack
> > +char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
> > +{
> > +	int len, ret;
> > +
> > +	if (!np || !np->parent)
> > +		return buf;
> > +
> > +	buf = device_node_gen_full_name(np->parent, buf, end);
> 
> This is recursive.  How many levels of parents could there be?
> Perhaps there should be a recursion limit.

Okay, unlike unflattening code, we can easily calculate the depth and 
then allocate an array on the stack. So this is what I've ended up 
with:

static int device_node_calc_depth(const struct device_node *np)
{
	int d;

	for (d = 0; np; d++)
		np = np->parent;

	return d;
}

static noinline_for_stack
char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
{
	int i;
	int depth = device_node_calc_depth(np);
	const struct device_node *nodes[depth];
	const struct printf_spec strspec = {
		.field_width = -1,
		.precision = -1,
	};

	if (!depth)
		return buf;
	/* special case for root node */
	if (depth == 1)
		return string(buf, end, "/", strspec);

	depth--;
	for (i = depth - 1; i >= 0; i--) {
		nodes[i] = np;
		np = np->parent;
	}
	for (i = 0; i < depth; i++) {
		buf = string(buf, end, "/", strspec);
		buf = string(buf, end, kbasename(nodes[i]->full_name), strspec);
	}
	return buf;
}


> > +	/* simple case without anything any more format specifiers */
> > +	if (fmt[1] == '\0' || strcspn(fmt + 1,"fnpPFcCr") > 0)
> > +		fmt = "Ff";
> > +
> > +	for (fmtp = fmt + 1, pass = false; strspn(fmtp,"fnpPFcCr"); fmtp++, pass = true) {
> 
> why not
> 	while (isalpha(*++fmt))
> like ip6 or isalnum like FORMAT_TYPE_PTR uses?

This case is more complicated with the field separators. If we have 
something like %pOFfxyz where xyz are not valid format specifiers, we'd 
end up with extra field separators.

I did simplify things a bit and got rid of fmtp and just use fmt 
instead.

Rob

Re: [PATCH 3/4] of: Custom printk format specifier for device node

[Joe Perches]

On Thu, 2017-06-15 at 16:26 -0500, Rob Herring wrote:
> On Wed, Jun 14, 2017 at 01:56:48PM -0700, Joe Perches wrote:
> > On Wed, 2017-06-14 at 15:30 -0500, Rob Herring wrote:
> > > From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
[]
> > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> > > []
> > > @@ -1470,6 +1471,123 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
> > >  	return format_flags(buf, end, flags, names);
> > >  }
> > >  
> > > +static noinline_for_stack
> > > +char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
> > > +{
> > > +	int len, ret;
> > > +
> > > +	if (!np || !np->parent)
> > > +		return buf;
> > > +
> > > +	buf = device_node_gen_full_name(np->parent, buf, end);
> > 
> > This is recursive.  How many levels of parents could there be?
> > Perhaps there should be a recursion limit.
> 
> Okay, unlike unflattening code, we can easily calculate the depth and 
> then allocate an array on the stack. So this is what I've ended up 
> with:
> 
> static int device_node_calc_depth(const struct device_node *np)
> {
> 	int d;
> 
> 	for (d = 0; np; d++)
> 		np = np->parent;
> 
> 	return d;
> }
> 
> static noinline_for_stack
> char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
> {
> 	int i;
> 	int depth = device_node_calc_depth(np);
> 	const struct device_node *nodes[depth];
> 	const struct printf_spec strspec = {
> 		.field_width = -1,
> 		.precision = -1,
> 	};

static const struct printf_spec strspec = { etc...
and please move strspec above *nodes

> 
> 	if (!depth)
> 		return buf;
> 	/* special case for root node */
> 	if (depth == 1)
> 		return string(buf, end, "/", strspec);
> 
> 	depth--;
> 	for (i = depth - 1; i >= 0; i--) {
> 		nodes[i] = np;
> 		np = np->parent;
> 	}
> 	for (i = 0; i < depth; i++) {
> 		buf = string(buf, end, "/", strspec);
> 		buf = string(buf, end, kbasename(nodes[i]->full_name), strspec);
> 	}
> 	return buf;
> }

Re: [PATCH 1/4] of: use kbasename instead of open coding

[Andy Shevchenko]

On Wed, Jun 14, 2017 at 11:30 PM, Rob Herring <robh@kernel.org> wrote:
> Several places in DT code open code the equivalent of kbasename.
> Replace them.
>
> The behavior for root nodes in node_name_cmp will be slightly different.
> Instead of comparing "/", "" will be compared. The comparison will be
> the same.

Reviewed-by: Andy Shevchenko <andy.shevhchenko@gmail.com>

>
> Signed-off-by: Rob Herring <robh@kernel.org>
> ---
>  drivers/of/base.c     | 5 +----
>  drivers/of/platform.c | 2 +-
>  drivers/of/resolver.c | 4 ++--
>  3 files changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 28d5f53bc631..054159ccd5f8 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -773,10 +773,7 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent,
>                 return NULL;
>
>         __for_each_child_of_node(parent, child) {
> -               const char *name = strrchr(child->full_name, '/');
> -               if (WARN(!name, "malformed device_node %s\n", child->full_name))
> -                       continue;
> -               name++;
> +               const char *name = kbasename(child->full_name);
>                 if (strncmp(path, name, len) == 0 && (strlen(name) == len))
>                         return child;
>         }
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 71fecc2debfc..8f73413fa243 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -99,7 +99,7 @@ static void of_device_make_bus_id(struct device *dev)
>
>                 /* format arguments only used if dev_name() resolves to NULL */
>                 dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
> -                            strrchr(node->full_name, '/') + 1, dev_name(dev));
> +                            kbasename(node->full_name), dev_name(dev));
>                 node = node->parent;
>         }
>  }
> diff --git a/drivers/of/resolver.c b/drivers/of/resolver.c
> index 771f4844c781..63626d7d9adb 100644
> --- a/drivers/of/resolver.c
> +++ b/drivers/of/resolver.c
> @@ -165,8 +165,8 @@ static int update_usages_of_a_phandle_reference(struct device_node *overlay,
>  static int node_name_cmp(const struct device_node *dn1,
>                 const struct device_node *dn2)
>  {
> -       const char *n1 = strrchr(dn1->full_name, '/') ? : "/";
> -       const char *n2 = strrchr(dn2->full_name, '/') ? : "/";
> +       const char *n1 = kbasename(dn1->full_name);
> +       const char *n2 = kbasename(dn2->full_name);
>
>         return of_node_cmp(n1, n2);
>  }
> --
> 2.11.0
>



-- 
With Best Regards,
Andy Shevchenko

[PATCH v2] vsprintf: Add %p extension "%pOF" for device tree

[Rob Herring]

From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>

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);

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>
Signed-off-by: Rob Herring <robh@kernel.org>
---
I missed some comments and changes Grant had done and incorporated them.

v2:
- Change subject
- Rewrite device_node_gen_full_name() to avoid recursion.
- Avoid using sprintf.
- Add unittests Grant L. wrote. 
- Drop ref count printing (from discussion 2 years ago).
- Remove fmtp local var.


 Documentation/printk-formats.txt             |  30 ++++++
 drivers/of/unittest-data/tests-platform.dtsi |   4 +-
 drivers/of/unittest.c                        |  58 +++++++++++
 lib/vsprintf.c                               | 140 +++++++++++++++++++++++++++
 scripts/checkpatch.pl                        |   2 +-
 5 files changed, 232 insertions(+), 2 deletions(-)

diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 5962949944fd..c7af38188f12 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -275,6 +275,36 @@ struct va_format:
 
 	Passed by reference.
 
+Device tree nodes:
+
+	%pOn[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:
+
+	%pOn	/foo/bar@0			- Node full name
+	%pOnf	/foo/bar@0			- Same as above
+	%pOnfp	/foo/bar@0:10			- Node full name + phandle
+	%pOnfcF	/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
diff --git a/drivers/of/unittest-data/tests-platform.dtsi b/drivers/of/unittest-data/tests-platform.dtsi
index eb20eeb2b062..a0c93822aee3 100644
--- a/drivers/of/unittest-data/tests-platform.dtsi
+++ b/drivers/of/unittest-data/tests-platform.dtsi
@@ -26,7 +26,9 @@
 				#size-cells = <0>;
 
 				dev@100 {
-					compatible = "test-sub-device";
+					compatible = "test-sub-device",
+						     "test-compat2",
+						     "test-compat3";
 					reg = <0x100>;
 				};
 			};
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 987a1530282a..8f611e9844db 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -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)
+{
+	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();
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 2d41de3f98a1..2343b2ca47c5 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 +1471,131 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
 	return format_flags(buf, end, flags, names);
 }
 
+static int device_node_calc_depth(const struct device_node *np)
+{
+	int d;
+
+	for (d = 0; np; d++)
+		np = np->parent;
+
+	return d;
+}
+
+static noinline_for_stack
+char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
+{
+	int i;
+	int depth = device_node_calc_depth(np);
+	static const struct printf_spec strspec = {
+		.field_width = -1,
+		.precision = -1,
+	};
+	const struct device_node *nodes[depth];
+
+	if (!depth)
+		return buf;
+	/* special case for root node */
+	if (depth == 1)
+		return string(buf, end, "/", strspec);
+
+	depth--;
+	for (i = depth - 1; i >= 0; i--) {
+		nodes[i] = np;
+		np = np->parent;
+	}
+	for (i = 0; i < depth; i++) {
+		buf = string(buf, end, "/", strspec);
+		buf = string(buf, end, kbasename(nodes[i]->full_name), 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' : '-';
+			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 +1692,15 @@ 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
+ * - '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 +1856,11 @@ 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) {
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 4b9569fa931b..411f2098fa6b 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -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;
 				}
-- 
2.11.0

Re: [PATCH v2] vsprintf: Add %p extension "%pOF" for device tree

[Randy Dunlap]

On 06/22/2017 01:44 PM, Rob Herring wrote:
> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> 
> 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);


isn't OF for flags -- and Of for full name?
Typo or a change in the last 2 years?

> 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>
> Signed-off-by: Rob Herring <robh@kernel.org>
> ---
> I missed some comments and changes Grant had done and incorporated them.
> 
> v2:
> - Change subject
> - Rewrite device_node_gen_full_name() to avoid recursion.
> - Avoid using sprintf.
> - Add unittests Grant L. wrote. 
> - Drop ref count printing (from discussion 2 years ago).
> - Remove fmtp local var.
> 
> 
>  Documentation/printk-formats.txt             |  30 ++++++
>  drivers/of/unittest-data/tests-platform.dtsi |   4 +-
>  drivers/of/unittest.c                        |  58 +++++++++++
>  lib/vsprintf.c                               | 140 +++++++++++++++++++++++++++
>  scripts/checkpatch.pl                        |   2 +-
>  5 files changed, 232 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
> index 5962949944fd..c7af38188f12 100644
> --- a/Documentation/printk-formats.txt
> +++ b/Documentation/printk-formats.txt
> @@ -275,6 +275,36 @@ struct va_format:
>  
>  	Passed by reference.
>  
> +Device tree nodes:
> +
> +	%pOn[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:
> +
> +	%pOn	/foo/bar@0			- Node full name
> +	%pOnf	/foo/bar@0			- Same as above
> +	%pOnfp	/foo/bar@0:10			- Node full name + phandle
> +	%pOnfcF	/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

-- 
~Randy

Re: [PATCH v2] vsprintf: Add %p extension "%pOF" for device tree

[Joe Perches]

On Thu, 2017-06-22 at 15:44 -0500, Rob Herring wrote:
> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> 
> 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);

I still think this should use another identifier like
%pO for object then another letter for type of object
maybe N for node.

And F is flags, f is name

> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
[]
> @@ -1470,6 +1471,131 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
>  	return format_flags(buf, end, flags, names);
>  }
>  
> +static int device_node_calc_depth(const struct device_node *np)
> +{
> +	int d;
> +
> +	for (d = 0; np; d++)
> +		np = np->parent;
> +
> +	return d;
> +}
> +
> +static noinline_for_stack
> +char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
> +{
> +	int i;
> +	int depth = device_node_calc_depth(np);
> +	static const struct printf_spec strspec = {
> +		.field_width = -1,
> +		.precision = -1,
> +	};
> +	const struct device_node *nodes[depth];
> +
> +	if (!depth)
> +		returnuf;
> +	/* special case for root node */
> +	if (depth == 1)
> +		return string(buf, end, "/", strspec);
> +
> +	depth--;
> +	for (i = depth - 1; i >= 0; i--) {
> +		nodes[i] = np;
> +		np = np->parent;
> +	}
> +	for (i = 0; i < depth; i++) {
> +		buf = string(buf, end, "/", strspec);
> +		buf = string(buf, end, kbasename(nodes[i]->full_name), strspec);
> +	}
> +	return buf;
> +}

I think there should be another function to get
a particular struct device_node * at a particular
depth to avoid all the pointers on stack.

Basically, adapt the for (i = depth - 1 loop to
a function that returns nodes[i]

Re: [PATCH v2] vsprintf: Add %p extension "%pOF" for device tree

[Rob Herring]

On Thu, Jun 22, 2017 at 5:44 PM, Randy Dunlap <rdunlap@infradead.org> wrote:
> On 06/22/2017 01:44 PM, Rob Herring wrote:
>> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
>>
>> 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);
>
>
> isn't OF for flags -- and Of for full name?
> Typo or a change in the last 2 years?

It changed in the discussion 2 years ago. The intent is:

%pO - kobj
%pOF - device_node, defaulting to full name

There's no support of base kobj's, but I guess I should make that
intent clear in the documentation.

Rob

Re: [PATCH v2] vsprintf: Add %p extension "%pOF" for device tree

[Rob Herring]

On Thu, Jun 22, 2017 at 10:01 PM, Joe Perches <joe@perches.com> wrote:
> On Thu, 2017-06-22 at 15:44 -0500, Rob Herring wrote:
>> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
>>
>> 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);
>
> I still think this should use another identifier like
> %pO for object then another letter for type of object
> maybe N for node.

It is. O is for kobj and F is for device node. It doesn't make a much
sense separately, but OF together makes sense as Open Firmware.

>
> And F is flags, f is name
>
>> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> []
>> @@ -1470,6 +1471,131 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
>>       return format_flags(buf, end, flags, names);
>>  }
>>
>> +static int device_node_calc_depth(const struct device_node *np)
>> +{
>> +     int d;
>> +
>> +     for (d = 0; np; d++)
>> +             np = np->parent;
>> +
>> +     return d;
>> +}
>> +
>> +static noinline_for_stack
>> +char *device_node_gen_full_name(const struct device_node *np, char *buf, char *end)
>> +{
>> +     int i;
>> +     int depth = device_node_calc_depth(np);
>> +     static const struct printf_spec strspec = {
>> +             .field_width = -1,
>> +             .precision = -1,
>> +     };
>> +     const struct device_node *nodes[depth];
>> +
>> +     if (!depth)
>> +             returnuf;
>> +     /* special case for root node */
>> +     if (depth == 1)
>> +             return string(buf, end, "/", strspec);
>> +
>> +     depth--;
>> +     for (i = depth - 1; i >= 0; i--) {
>> +             nodes[i] = np;
>> +             np = np->parent;
>> +     }
>> +     for (i = 0; i < depth; i++) {
>> +             buf = string(buf, end, "/", strspec);
>> +             buf = string(buf, end, kbasename(nodes[i]->full_name), strspec);
>> +     }
>> +     return buf;
>> +}
>
> I think there should be another function to get
> a particular struct device_node * at a particular
> depth to avoid all the pointers on stack.
>
> Basically, adapt the for (i = depth - 1 loop to
> a function that returns nodes[i]

Okay.

Rob

[PATCH v3] vsprintf: Add %p extension "%pOF" for device tree

[Rob Herring]

From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>

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>
Signed-off-by: Rob Herring <robh@kernel.org>
---
v3:
- Fix missing documentation updates using '%pOF' as the device_node 
  specifier.
- Update the commit msg and documentation to clearly define '%pO' is the
  base specifier for kobjects.
- Rework device_node_gen_full_name() to avoid creating an array of node
  pointers on the stack.

v2:
- Change subject
- Rewrite device_node_gen_full_name() to avoid recursion.
- Avoid using sprintf.
- Add unittests Grant L. wrote. 
- Drop ref count printing (from discussion 2 years ago).
- Remove fmtp local var.


 Documentation/printk-formats.txt             |  36 +++++++
 drivers/of/unittest-data/tests-platform.dtsi |   4 +-
 drivers/of/unittest.c                        |  58 ++++++++++++
 lib/vsprintf.c                               | 135 +++++++++++++++++++++++++++
 scripts/checkpatch.pl                        |   2 +-
 5 files changed, 233 insertions(+), 2 deletions(-)

diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 5962949944fd..619cdffa5d44 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -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
diff --git a/drivers/of/unittest-data/tests-platform.dtsi b/drivers/of/unittest-data/tests-platform.dtsi
index eb20eeb2b062..a0c93822aee3 100644
--- a/drivers/of/unittest-data/tests-platform.dtsi
+++ b/drivers/of/unittest-data/tests-platform.dtsi
@@ -26,7 +26,9 @@
 				#size-cells = <0>;
 
 				dev@100 {
-					compatible = "test-sub-device";
+					compatible = "test-sub-device",
+						     "test-compat2",
+						     "test-compat3";
 					reg = <0x100>;
 				};
 			};
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 987a1530282a..8f611e9844db 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -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)
+{
+	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();
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 2d41de3f98a1..9e2e9306fd24 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 +1471,125 @@ 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' : '-';
+			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 +1686,16 @@ 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 +1851,11 @@ 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) {
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 4b9569fa931b..411f2098fa6b 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -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;
 				}
-- 
2.11.0

Re: [PATCH v3] vsprintf: Add %p extension "%pOF" for device tree

[Joe Perches]

On Fri, 2017-06-23 at 12:30 -0500, Rob Herring wrote:
> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> 
> 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>
> Signed-off-by: Rob Herring <robh@kernel.org>
> ---
> v3:
> - Fix missing documentation updates using '%pOF' as the device_node 
>   specifier.
> - Update the commit msg and documentation to clearly define '%pO' is the
>   base specifier for kobjects.
> - Rework device_node_gen_full_name() to avoid creating an array of node
>   pointers on the stack.

Thanks Rob.

This all seems sensible to me now.

If you want:

Acked-by: Joe Perches <joe@perches.com>

cheers, Joe