[PATCH 0/6 v2] of: Implement iterator for phandles

[PATCH 0/6 v2] of: Implement iterator for phandles

[Joerg Roedel]

Hi,

here is a new version of the implementation of the iterator
over phandles concept which Rob Herring suggested to me some
time ago. My approach is a little bit different from what
the diff showed back then, but it gets rid of the allocation
and 'struct of_phandle_args' misuse.

I also converted the arm-smmu driver to make use of the
iterator. The resulting kernel boots on my AMD Seattle
system and fixes the warning triggered there. The patches
now also pass all dt-unittests in my kvm environment.

Patches are based on v4.6-rc2

Thanks,

	Joerg

Changes since v1:

* Rebased to v4.6-rc2

* Removed the 'if (i == 0)...' hunk from the last patch

* Tested again with DT unit-tests and on the seattle system

Changes since RFC post:

* Reordered members of 'struct of_phandle_iterator' and did
  some renaming

* Removed index counting from the iterator

* Split up iterator implementation into multiple patches

* Fixed the code to survive all dt-unittests, tested with each
  patch in this series

* Re-added and updated some comments which got lost during the
  conversion.

* Added of_for_each_phandle macro for easier handling

* Moved the counting special-case from __of_parse_phandle_with_args
  directly to of_count_phandle_with_args for code
  simplification

* Removed some iterator helper functions

* Formatting and style changes

Joerg Roedel (6):
  of: Introduce struct of_phandle_iterator
  of: Move phandle walking to of_phandle_iterator_next()
  of: Remove counting special case from __of_parse_phandle_with_args()
  of: Introduce of_for_each_phandle() helper macro
  of: Introduce of_phandle_iterator_args()
  iommu/arm-smmu: Make use of phandle iterators in device-tree parsing

 drivers/iommu/arm-smmu.c |  38 +++++++--
 drivers/of/base.c        | 206 ++++++++++++++++++++++++++++++-----------------
 include/linux/of.h       |  56 +++++++++++++
 3 files changed, 219 insertions(+), 81 deletions(-)

-- 
1.9.1

[PATCH 1/6] of: Introduce struct of_phandle_iterator

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

This struct carrys all necessary information to iterate over
a list of phandles and extract the arguments. Add an
init-function for the iterator and make use of it in
__of_parse_phandle_with_args().

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Rob Herring <robh@kernel.org>
---
 drivers/of/base.c  | 99 +++++++++++++++++++++++++++++++++---------------------
 include/linux/of.h | 33 ++++++++++++++++++
 2 files changed, 93 insertions(+), 39 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index b299de2..1c6f43b 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1440,35 +1440,56 @@ void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
 	printk("\n");
 }
 
+int of_phandle_iterator_init(struct of_phandle_iterator *it,
+		const struct device_node *np,
+		const char *list_name,
+		const char *cells_name,
+		int cell_count)
+{
+	const __be32 *list;
+	int size;
+
+	memset(it, 0, sizeof(*it));
+
+	list = of_get_property(np, list_name, &size);
+	if (!list)
+		return -ENOENT;
+
+	it->cells_name = cells_name;
+	it->cell_count = cell_count;
+	it->parent = np;
+	it->list_end = list + size / sizeof(*list);
+	it->phandle_end = list;
+	it->cur = list;
+
+	return 0;
+}
+
 static int __of_parse_phandle_with_args(const struct device_node *np,
 					const char *list_name,
 					const char *cells_name,
 					int cell_count, int index,
 					struct of_phandle_args *out_args)
 {
-	const __be32 *list, *list_end;
-	int rc = 0, size, cur_index = 0;
-	uint32_t count = 0;
-	struct device_node *node = NULL;
-	phandle phandle;
+	struct of_phandle_iterator it;
+	int rc, cur_index = 0;
 
-	/* Retrieve the phandle list property */
-	list = of_get_property(np, list_name, &size);
-	if (!list)
-		return -ENOENT;
-	list_end = list + size / sizeof(*list);
+	rc = of_phandle_iterator_init(&it, np, list_name,
+				      cells_name, cell_count);
+	if (rc)
+		return rc;
 
 	/* Loop over the phandles until all the requested entry is found */
-	while (list < list_end) {
+	while (it.cur < it.list_end) {
 		rc = -EINVAL;
-		count = 0;
+		it.cur_count = 0;
 
 		/*
 		 * If phandle is 0, then it is an empty entry with no
 		 * arguments.  Skip forward to the next entry.
 		 */
-		phandle = be32_to_cpup(list++);
-		if (phandle) {
+		it.phandle = be32_to_cpup(it.cur++);
+		if (it.phandle) {
 			/*
 			 * Find the provider node and parse the #*-cells
 			 * property to determine the argument length.
@@ -1478,34 +1499,34 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 			 * except when we're going to return the found node
 			 * below.
 			 */
-			if (cells_name || cur_index == index) {
-				node = of_find_node_by_phandle(phandle);
-				if (!node) {
+			if (it.cells_name || cur_index == index) {
+				it.node = of_find_node_by_phandle(it.phandle);
+				if (!it.node) {
 					pr_err("%s: could not find phandle\n",
-						np->full_name);
+						it.parent->full_name);
 					goto err;
 				}
 			}
 
-			if (cells_name) {
-				if (of_property_read_u32(node, cells_name,
-							 &count)) {
+			if (it.cells_name) {
+				if (of_property_read_u32(it.node, it.cells_name,
+							 &it.cur_count)) {
 					pr_err("%s: could not get %s for %s\n",
-						np->full_name, cells_name,
-						node->full_name);
+						it.parent->full_name, it.cells_name,
+						it.node->full_name);
 					goto err;
 				}
 			} else {
-				count = cell_count;
+				it.cur_count = it.cell_count;
 			}
 
 			/*
 			 * Make sure that the arguments actually fit in the
 			 * remaining property data length
 			 */
-			if (list + count > list_end) {
+			if (it.cur + it.cur_count > it.list_end) {
 				pr_err("%s: arguments longer than property\n",
-					 np->full_name);
+					 it.parent->full_name);
 				goto err;
 			}
 		}
@@ -1518,28 +1539,28 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 		 */
 		rc = -ENOENT;
 		if (cur_index == index) {
-			if (!phandle)
+			if (!it.phandle)
 				goto err;
 
 			if (out_args) {
 				int i;
-				if (WARN_ON(count > MAX_PHANDLE_ARGS))
-					count = MAX_PHANDLE_ARGS;
-				out_args->np = node;
-				out_args->args_count = count;
-				for (i = 0; i < count; i++)
-					out_args->args[i] = be32_to_cpup(list++);
+				if (WARN_ON(it.cur_count > MAX_PHANDLE_ARGS))
+					it.cur_count = MAX_PHANDLE_ARGS;
+				out_args->np = it.node;
+				out_args->args_count = it.cur_count;
+				for (i = 0; i < it.cur_count; i++)
+					out_args->args[i] = be32_to_cpup(it.cur++);
 			} else {
-				of_node_put(node);
+				of_node_put(it.node);
 			}
 
 			/* Found it! return success */
 			return 0;
 		}
 
-		of_node_put(node);
-		node = NULL;
-		list += count;
+		of_node_put(it.node);
+		it.node = NULL;
+		it.cur += it.cur_count;
 		cur_index++;
 	}
 
@@ -1551,8 +1572,8 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 	 */
 	rc = index < 0 ? cur_index : -ENOENT;
  err:
-	if (node)
-		of_node_put(node);
+	if (it.node)
+		of_node_put(it.node);
 	return rc;
 }
 
diff --git a/include/linux/of.h b/include/linux/of.h
index 7fcb681..0f187db 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -75,6 +75,23 @@ struct of_phandle_args {
 	uint32_t args[MAX_PHANDLE_ARGS];
 };
 
+struct of_phandle_iterator {
+	/* Common iterator information */
+	const char *cells_name;
+	int cell_count;
+	const struct device_node *parent;
+
+	/* List size information */
+	const __be32 *list_end;
+	const __be32 *phandle_end;
+
+	/* Current position state */
+	const __be32 *cur;
+	uint32_t cur_count;
+	phandle phandle;
+	struct device_node *node;
+};
+
 struct of_reconfig_data {
 	struct device_node	*dn;
 	struct property		*prop;
@@ -334,6 +351,13 @@ extern int of_parse_phandle_with_fixed_args(const struct device_node *np,
 extern int of_count_phandle_with_args(const struct device_node *np,
 	const char *list_name, const char *cells_name);
 
+/* phandle iterator functions */
+extern int of_phandle_iterator_init(struct of_phandle_iterator *it,
+				    const struct device_node *np,
+				    const char *list_name,
+				    const char *cells_name,
+				    int cell_count);
+
 extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));
 extern int of_alias_get_id(struct device_node *np, const char *stem);
 extern int of_alias_get_highest_id(const char *stem);
@@ -608,6 +632,15 @@ static inline int of_count_phandle_with_args(struct device_node *np,
 	return -ENOSYS;
 }
 
+static inline int of_phandle_iterator_init(struct of_phandle_iterator *it,
+					   const struct device_node *np,
+					   const char *list_name,
+					   const char *cells_name,
+					   int cell_count)
+{
+	return -ENOSYS;
+}
+
 static inline int of_alias_get_id(struct device_node *np, const char *stem)
 {
 	return -ENOSYS;
-- 
1.9.1

[PATCH 2/6] of: Move phandle walking to of_phandle_iterator_next()

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

Move the code to walk over the phandles out of the loop in
__of_parse_phandle_with_args() to a separate function that
just works with the iterator handle: of_phandle_iterator_next().

Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/of/base.c  | 130 ++++++++++++++++++++++++++++++-----------------------
 include/linux/of.h |   7 +++
 2 files changed, 81 insertions(+), 56 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 1c6f43b..69286ec 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1465,6 +1465,75 @@ int of_phandle_iterator_init(struct of_phandle_iterator *it,
 	return 0;
 }
 
+int of_phandle_iterator_next(struct of_phandle_iterator *it)
+{
+	uint32_t count = 0;
+
+	if (it->node) {
+		of_node_put(it->node);
+		it->node = NULL;
+	}
+
+	if (!it->cur || it->phandle_end >= it->list_end)
+		return -ENOENT;
+
+	it->cur = it->phandle_end;
+
+	/* If phandle is 0, then it is an empty entry with no arguments. */
+	it->phandle = be32_to_cpup(it->cur++);
+
+	if (it->phandle) {
+
+		/*
+		 * Find the provider node and parse the #*-cells property to
+		 * determine the argument length.
+		 */
+		it->node = of_find_node_by_phandle(it->phandle);
+
+		if (it->cells_name) {
+			if (!it->node) {
+				pr_err("%s: could not find phandle\n",
+				       it->parent->full_name);
+				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,
+				       it->cells_name,
+				       it->node->full_name);
+				goto err;
+			}
+		} else {
+			count = it->cell_count;
+		}
+
+		/*
+		 * Make sure that the arguments actually fit in the remaining
+		 * property data length
+		 */
+		if (it->cur + count > it->list_end) {
+			pr_err("%s: arguments longer than property\n",
+			       it->parent->full_name);
+			goto err;
+		}
+	}
+
+	it->phandle_end = it->cur + count;
+	it->cur_count = count;
+
+	return 0;
+
+err:
+	if (it->node) {
+		of_node_put(it->node);
+		it->node = NULL;
+	}
+
+	return -EINVAL;
+}
+
 static int __of_parse_phandle_with_args(const struct device_node *np,
 					const char *list_name,
 					const char *cells_name,
@@ -1480,59 +1549,9 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 		return rc;
 
 	/* Loop over the phandles until all the requested entry is found */
-	while (it.cur < it.list_end) {
-		rc = -EINVAL;
-		it.cur_count = 0;
-
-		/*
-		 * If phandle is 0, then it is an empty entry with no
-		 * arguments.  Skip forward to the next entry.
-		 */
-		it.phandle = be32_to_cpup(it.cur++);
-		if (it.phandle) {
-			/*
-			 * Find the provider node and parse the #*-cells
-			 * property to determine the argument length.
-			 *
-			 * This is not needed if the cell count is hard-coded
-			 * (i.e. cells_name not set, but cell_count is set),
-			 * except when we're going to return the found node
-			 * below.
-			 */
-			if (it.cells_name || cur_index == index) {
-				it.node = of_find_node_by_phandle(it.phandle);
-				if (!it.node) {
-					pr_err("%s: could not find phandle\n",
-						it.parent->full_name);
-					goto err;
-				}
-			}
-
-			if (it.cells_name) {
-				if (of_property_read_u32(it.node, it.cells_name,
-							 &it.cur_count)) {
-					pr_err("%s: could not get %s for %s\n",
-						it.parent->full_name, it.cells_name,
-						it.node->full_name);
-					goto err;
-				}
-			} else {
-				it.cur_count = it.cell_count;
-			}
-
-			/*
-			 * Make sure that the arguments actually fit in the
-			 * remaining property data length
-			 */
-			if (it.cur + it.cur_count > it.list_end) {
-				pr_err("%s: arguments longer than property\n",
-					 it.parent->full_name);
-				goto err;
-			}
-		}
-
+	while ((rc = of_phandle_iterator_next(&it)) == 0) {
 		/*
-		 * All of the error cases above bail out of the loop, so at
+		 * All of the error cases bail out of the loop, so at
 		 * this point, the parsing is successful. If the requested
 		 * index matches, then fill the out_args structure and return,
 		 * or return -ENOENT for an empty entry.
@@ -1558,9 +1577,6 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 			return 0;
 		}
 
-		of_node_put(it.node);
-		it.node = NULL;
-		it.cur += it.cur_count;
 		cur_index++;
 	}
 
@@ -1570,7 +1586,9 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 	 * -EINVAL : parsing error on data
 	 * [1..n]  : Number of phandle (count mode; when index = -1)
 	 */
-	rc = index < 0 ? cur_index : -ENOENT;
+	if (rc == -ENOENT && index < 0)
+		rc = cur_index;
+
  err:
 	if (it.node)
 		of_node_put(it.node);
diff --git a/include/linux/of.h b/include/linux/of.h
index 0f187db..1f5e108 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -358,6 +358,8 @@ extern int of_phandle_iterator_init(struct of_phandle_iterator *it,
 				    const char *cells_name,
 				    int cell_count);
 
+extern int of_phandle_iterator_next(struct of_phandle_iterator *it);
+
 extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));
 extern int of_alias_get_id(struct device_node *np, const char *stem);
 extern int of_alias_get_highest_id(const char *stem);
@@ -641,6 +643,11 @@ static inline int of_phandle_iterator_init(struct of_phandle_iterator *it,
 	return -ENOSYS;
 }
 
+static inline int of_phandle_iterator_next(struct of_phandle_iterator *it)
+{
+	return -ENOSYS;
+}
+
 static inline int of_alias_get_id(struct device_node *np, const char *stem)
 {
 	return -ENOSYS;
-- 
1.9.1

[PATCH 3/6] of: Remove counting special case from __of_parse_phandle_with_args()

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

The index = -1 case in __of_parse_phandle_with_args() is
used to just return the number of phandles. That special
case needs extra handling, so move it to the place where it
is needed: of_count_phandle_with_args().

This allows to further simplify __of_parse_phandle_with_args()
later on.

Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/of/base.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 69286ec..fcff2b6 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1584,10 +1584,7 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 	 * Unlock node before returning result; will be one of:
 	 * -ENOENT : index is for empty phandle
 	 * -EINVAL : parsing error on data
-	 * [1..n]  : Number of phandle (count mode; when index = -1)
 	 */
-	if (rc == -ENOENT && index < 0)
-		rc = cur_index;
 
  err:
 	if (it.node)
@@ -1723,8 +1720,20 @@ EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
 				const char *cells_name)
 {
-	return __of_parse_phandle_with_args(np, list_name, cells_name, 0, -1,
-					    NULL);
+	struct of_phandle_iterator it;
+	int rc, cur_index = 0;
+
+	rc = of_phandle_iterator_init(&it, np, list_name, cells_name, 0);
+	if (rc)
+		return rc;
+
+	while ((rc = of_phandle_iterator_next(&it)) == 0)
+		cur_index += 1;
+
+	if (rc != -ENOENT)
+		return rc;
+
+	return cur_index;
 }
 EXPORT_SYMBOL(of_count_phandle_with_args);
 
-- 
1.9.1

[PATCH 4/6] of: Introduce of_for_each_phandle() helper macro

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

With this macro any user can easily iterate over a list of
phandles. The patch also converts __of_parse_phandle_with_args()
to make use of the macro.

The of_count_phandle_with_args() function is not converted,
because the macro hides the return value of of_phandle_iterator_init(),
which is needed in there.

Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/of/base.c  | 7 +------
 include/linux/of.h | 6 ++++++
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index fcff2b6..ea5a13d 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1543,13 +1543,8 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 	struct of_phandle_iterator it;
 	int rc, cur_index = 0;
 
-	rc = of_phandle_iterator_init(&it, np, list_name,
-				      cells_name, cell_count);
-	if (rc)
-		return rc;
-
 	/* Loop over the phandles until all the requested entry is found */
-	while ((rc = of_phandle_iterator_next(&it)) == 0) {
+	of_for_each_phandle(&it, rc, np, list_name, cells_name, cell_count) {
 		/*
 		 * All of the error cases bail out of the loop, so at
 		 * this point, the parsing is successful. If the requested
diff --git a/include/linux/of.h b/include/linux/of.h
index 1f5e108..b0b8071 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -908,6 +908,12 @@ static inline int of_property_read_s32(const struct device_node *np,
 	return of_property_read_u32(np, propname, (u32*) out_value);
 }
 
+#define of_for_each_phandle(it, err, np, ln, cn, cc)			\
+	for (of_phandle_iterator_init((it), (np), (ln), (cn), (cc)),	\
+	     err = of_phandle_iterator_next(it);			\
+	     err == 0;							\
+	     err = of_phandle_iterator_next(it))
+
 #define of_property_for_each_u32(np, propname, prop, p, u)	\
 	for (prop = of_find_property(np, propname, NULL),	\
 		p = of_prop_next_u32(prop, NULL, &u);		\
-- 
1.9.1

[PATCH 5/6] of: Introduce of_phandle_iterator_args()

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

This helper function can be used to copy the arguments of a
phandle to an array.

Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/of/base.c  | 29 +++++++++++++++++++++++------
 include/linux/of.h | 10 ++++++++++
 2 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index ea5a13d..e87e21d 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1534,6 +1534,23 @@ err:
 	return -EINVAL;
 }
 
+int of_phandle_iterator_args(struct of_phandle_iterator *it,
+			     uint32_t *args,
+			     int size)
+{
+	int i, count;
+
+	count = it->cur_count;
+
+	if (WARN_ON(size < count))
+		count = size;
+
+	for (i = 0; i < count; i++)
+		args[i] = be32_to_cpup(it->cur++);
+
+	return count;
+}
+
 static int __of_parse_phandle_with_args(const struct device_node *np,
 					const char *list_name,
 					const char *cells_name,
@@ -1557,13 +1574,13 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 				goto err;
 
 			if (out_args) {
-				int i;
-				if (WARN_ON(it.cur_count > MAX_PHANDLE_ARGS))
-					it.cur_count = MAX_PHANDLE_ARGS;
+				int c;
+
+				c = of_phandle_iterator_args(&it,
+							     out_args->args,
+							     MAX_PHANDLE_ARGS);
 				out_args->np = it.node;
-				out_args->args_count = it.cur_count;
-				for (i = 0; i < it.cur_count; i++)
-					out_args->args[i] = be32_to_cpup(it.cur++);
+				out_args->args_count = c;
 			} else {
 				of_node_put(it.node);
 			}
diff --git a/include/linux/of.h b/include/linux/of.h
index b0b8071..71e1c35 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -359,6 +359,9 @@ extern int of_phandle_iterator_init(struct of_phandle_iterator *it,
 				    int cell_count);
 
 extern int of_phandle_iterator_next(struct of_phandle_iterator *it);
+extern int of_phandle_iterator_args(struct of_phandle_iterator *it,
+				    uint32_t *args,
+				    int size);
 
 extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));
 extern int of_alias_get_id(struct device_node *np, const char *stem);
@@ -648,6 +651,13 @@ static inline int of_phandle_iterator_next(struct of_phandle_iterator *it)
 	return -ENOSYS;
 }
 
+static inline int of_phandle_iterator_args(struct of_phandle_iterator *it,
+					   uint32_t *args,
+					   int size)
+{
+	return 0;
+}
+
 static inline int of_alias_get_id(struct device_node *np, const char *stem)
 {
 	return -ENOSYS;
-- 
1.9.1

[PATCH 6/6] iommu/arm-smmu: Make use of phandle iterators in device-tree parsing

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

Remove the usage of of_parse_phandle_with_args() and replace
it by the phandle-iterator implementation so that we can
parse out all of the potentially present 128 stream-ids.

Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
---
 drivers/iommu/arm-smmu.c | 38 ++++++++++++++++++++++++++++++--------
 1 file changed, 30 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 2409e3b..a1c965c 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -49,7 +49,7 @@
 #include "io-pgtable.h"
 
 /* Maximum number of stream IDs assigned to a single device */
-#define MAX_MASTER_STREAMIDS		MAX_PHANDLE_ARGS
+#define MAX_MASTER_STREAMIDS		128
 
 /* Maximum number of context banks per SMMU */
 #define ARM_SMMU_MAX_CBS		128
@@ -357,6 +357,12 @@ struct arm_smmu_domain {
 	struct iommu_domain		domain;
 };
 
+struct arm_smmu_phandle_args {
+	struct device_node *np;
+	int args_count;
+	uint32_t args[MAX_MASTER_STREAMIDS];
+};
+
 static struct iommu_ops arm_smmu_ops;
 
 static DEFINE_SPINLOCK(arm_smmu_devices_lock);
@@ -466,7 +472,7 @@ static int insert_smmu_master(struct arm_smmu_device *smmu,
 
 static int register_smmu_master(struct arm_smmu_device *smmu,
 				struct device *dev,
-				struct of_phandle_args *masterspec)
+				struct arm_smmu_phandle_args *masterspec)
 {
 	int i;
 	struct arm_smmu_master *master;
@@ -1737,7 +1743,8 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
 	struct arm_smmu_device *smmu;
 	struct device *dev = &pdev->dev;
 	struct rb_node *node;
-	struct of_phandle_args masterspec;
+	struct of_phandle_iterator it;
+	struct arm_smmu_phandle_args *masterspec;
 	int num_irqs, i, err;
 
 	smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
@@ -1798,20 +1805,35 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
 
 	i = 0;
 	smmu->masters = RB_ROOT;
-	while (!of_parse_phandle_with_args(dev->of_node, "mmu-masters",
-					   "#stream-id-cells", i,
-					   &masterspec)) {
-		err = register_smmu_master(smmu, dev, &masterspec);
+
+	err = -ENOMEM;
+	/* No need to zero the memory for masterspec */
+	masterspec = kmalloc(sizeof(*masterspec), GFP_KERNEL);
+	if (!masterspec)
+		goto out_put_masters;
+
+	of_for_each_phandle(&it, err, dev->of_node,
+			    "mmu-masters", "#stream-id-cells", 0) {
+		int count = of_phandle_iterator_args(&it, masterspec->args,
+						     MAX_MASTER_STREAMIDS);
+		masterspec->np		= of_node_get(it.node);
+		masterspec->args_count	= count;
+
+		err = register_smmu_master(smmu, dev, masterspec);
 		if (err) {
 			dev_err(dev, "failed to add master %s\n",
-				masterspec.np->name);
+				masterspec->np->name);
+			kfree(masterspec);
 			goto out_put_masters;
 		}
 
 		i++;
 	}
+
 	dev_notice(dev, "registered %d master devices\n", i);
 
+	kfree(masterspec);
+
 	parse_driver_options(smmu);
 
 	if (smmu->version > ARM_SMMU_V1 &&
-- 
1.9.1

Re: [PATCH 6/6] iommu/arm-smmu: Make use of phandle iterators in device-tree parsing

[Will Deacon]

Hi Joerg,

On Mon, Apr 04, 2016 at 05:49:22PM +0200, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
> 
> Remove the usage of of_parse_phandle_with_args() and replace
> it by the phandle-iterator implementation so that we can
> parse out all of the potentially present 128 stream-ids.
> 
> Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
> ---
>  drivers/iommu/arm-smmu.c | 38 ++++++++++++++++++++++++++++++--------
>  1 file changed, 30 insertions(+), 8 deletions(-)

Looks good to me. Given that you probably want to keep this with the
related DT changes:

Acked-by: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>

Thanks,

Will

Re: [PATCH 0/6 v2] of: Implement iterator for phandles

[Rob Herring]

On Mon, Apr 4, 2016 at 10:49 AM, Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org> wrote:
> Hi,
>
> here is a new version of the implementation of the iterator
> over phandles concept which Rob Herring suggested to me some
> time ago. My approach is a little bit different from what
> the diff showed back then, but it gets rid of the allocation
> and 'struct of_phandle_args' misuse.
>
> I also converted the arm-smmu driver to make use of the
> iterator. The resulting kernel boots on my AMD Seattle
> system and fixes the warning triggered there. The patches
> now also pass all dt-unittests in my kvm environment.
>
> Patches are based on v4.6-rc2

Series now applied.

Rob

[PATCH 0/6] of: Implement iterator for phandles

[Joerg Roedel]

Hi,

here is an implementation of the iterator over phandles
concept which Rob Herring suggested to me some time ago. My
approach is a little bit different from what the diff showed
back then, but it gets rid of the allocation and 'struct
'struct of_phandle_args' misuse.

I also converted the arm-smmu driver to make use of the
iterator. The resulting kernel boots on my AMD Seattle
system and fixes the warning triggered there. The patches
now also pass all dt-unittests in my kvm environment.

Please review. Patches are based on v4.5.

Thanks,

	Joerg

Changes since RFC post:

* Reordered members of 'struct of_phandle_iterator' and did
  some renaming

* Removed index counting from the iterator

* Split up iterator implementation into multiple patches

* Fixed the code to survive all dt-unittests, tested with each
  patch in this series

* Re-added and updated some comments which got lost during the
  conversion.

* Added of_for_each_phandle macro for easier handling

* Moved the counting special-case from __of_parse_phandle_with_args
  directly to of_count_phandle_with_args for code
  simplification

* Removed some iterator helper functions

* Formatting and style changes

Joerg Roedel (6):
  of: Introduce struct of_phandle_iterator
  of: Move phandle walking to of_phandle_iterator_next()
  of: Remove counting special case from __of_parse_phandle_with_args()
  of: Introduce of_for_each_phandle() helper macro
  of: Introduce of_phandle_iterator_args()
  iommu/arm-smmu: Make use of phandle iterators in device-tree parsing

 drivers/iommu/arm-smmu.c |  28 +++++--
 drivers/of/base.c        | 206 ++++++++++++++++++++++++++++++-----------------
 include/linux/of.h       |  56 +++++++++++++
 3 files changed, 211 insertions(+), 79 deletions(-)

-- 
1.9.1

[PATCH 2/6] of: Move phandle walking to of_phandle_iterator_next()

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

Move the code to walk over the phandles out of the loop in
__of_parse_phandle_with_args() to a separate function that
just works with the iterator handle: of_phandle_iterator_next().

Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
---
 drivers/of/base.c  | 130 ++++++++++++++++++++++++++++++-----------------------
 include/linux/of.h |   7 +++
 2 files changed, 81 insertions(+), 56 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index bfdb09b..4036512 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1464,6 +1464,75 @@ int of_phandle_iterator_init(struct of_phandle_iterator *it,
 	return 0;
 }
 
+int of_phandle_iterator_next(struct of_phandle_iterator *it)
+{
+	uint32_t count = 0;
+
+	if (it->node) {
+		of_node_put(it->node);
+		it->node = NULL;
+	}
+
+	if (!it->cur || it->phandle_end >= it->list_end)
+		return -ENOENT;
+
+	it->cur = it->phandle_end;
+
+	/* If phandle is 0, then it is an empty entry with no arguments. */
+	it->phandle = be32_to_cpup(it->cur++);
+
+	if (it->phandle) {
+
+		/*
+		 * Find the provider node and parse the #*-cells property to
+		 * determine the argument length.
+		 */
+		it->node = of_find_node_by_phandle(it->phandle);
+
+		if (it->cells_name) {
+			if (!it->node) {
+				pr_err("%s: could not find phandle\n",
+				       it->parent->full_name);
+				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,
+				       it->cells_name,
+				       it->node->full_name);
+				goto err;
+			}
+		} else {
+			count = it->cell_count;
+		}
+
+		/*
+		 * Make sure that the arguments actually fit in the remaining
+		 * property data length
+		 */
+		if (it->cur + count > it->list_end) {
+			pr_err("%s: arguments longer than property\n",
+			       it->parent->full_name);
+			goto err;
+		}
+	}
+
+	it->phandle_end = it->cur + count;
+	it->cur_count = count;
+
+	return 0;
+
+err:
+	if (it->node) {
+		of_node_put(it->node);
+		it->node = NULL;
+	}
+
+	return -EINVAL;
+}
+
 static int __of_parse_phandle_with_args(const struct device_node *np,
 					const char *list_name,
 					const char *cells_name,
@@ -1479,59 +1548,9 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 		return rc;
 
 	/* Loop over the phandles until all the requested entry is found */
-	while (it.cur < it.list_end) {
-		rc = -EINVAL;
-		it.cur_count = 0;
-
-		/*
-		 * If phandle is 0, then it is an empty entry with no
-		 * arguments.  Skip forward to the next entry.
-		 */
-		it.phandle = be32_to_cpup(it.cur++);
-		if (it.phandle) {
-			/*
-			 * Find the provider node and parse the #*-cells
-			 * property to determine the argument length.
-			 *
-			 * This is not needed if the cell count is hard-coded
-			 * (i.e. cells_name not set, but cell_count is set),
-			 * except when we're going to return the found node
-			 * below.
-			 */
-			if (it.cells_name || cur_index == index) {
-				it.node = of_find_node_by_phandle(it.phandle);
-				if (!it.node) {
-					pr_err("%s: could not find phandle\n",
-						it.parent->full_name);
-					goto err;
-				}
-			}
-
-			if (it.cells_name) {
-				if (of_property_read_u32(it.node, it.cells_name,
-							 &it.cur_count)) {
-					pr_err("%s: could not get %s for %s\n",
-						it.parent->full_name, it.cells_name,
-						it.node->full_name);
-					goto err;
-				}
-			} else {
-				it.cur_count = it.cell_count;
-			}
-
-			/*
-			 * Make sure that the arguments actually fit in the
-			 * remaining property data length
-			 */
-			if (it.cur + it.cur_count > it.list_end) {
-				pr_err("%s: arguments longer than property\n",
-					 it.parent->full_name);
-				goto err;
-			}
-		}
-
+	while ((rc = of_phandle_iterator_next(&it)) == 0) {
 		/*
-		 * All of the error cases above bail out of the loop, so at
+		 * All of the error cases bail out of the loop, so at
 		 * this point, the parsing is successful. If the requested
 		 * index matches, then fill the out_args structure and return,
 		 * or return -ENOENT for an empty entry.
@@ -1557,9 +1576,6 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 			return 0;
 		}
 
-		of_node_put(it.node);
-		it.node = NULL;
-		it.cur += it.cur_count;
 		cur_index++;
 	}
 
@@ -1569,7 +1585,9 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 	 * -EINVAL : parsing error on data
 	 * [1..n]  : Number of phandle (count mode; when index = -1)
 	 */
-	rc = index < 0 ? cur_index : -ENOENT;
+	if (rc == -ENOENT && index < 0)
+		rc = cur_index;
+
  err:
 	if (it.node)
 		of_node_put(it.node);
diff --git a/include/linux/of.h b/include/linux/of.h
index 70c2bdb..d94388b0 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -358,6 +358,8 @@ extern int of_phandle_iterator_init(struct of_phandle_iterator *it,
 				    const char *cells_name,
 				    int cell_count);
 
+extern int of_phandle_iterator_next(struct of_phandle_iterator *it);
+
 extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));
 extern int of_alias_get_id(struct device_node *np, const char *stem);
 extern int of_alias_get_highest_id(const char *stem);
@@ -641,6 +643,11 @@ static inline int of_phandle_iterator_init(struct of_phandle_iterator *it,
 	return -ENOSYS;
 }
 
+static inline int of_phandle_iterator_next(struct of_phandle_iterator *it)
+{
+	return -ENOSYS;
+}
+
 static inline int of_alias_get_id(struct device_node *np, const char *stem)
 {
 	return -ENOSYS;
-- 
1.9.1