[PATCHv2 0/3] OF phandle nexus support + GPIO nexus

[PATCHv2 0/3] OF phandle nexus support + GPIO nexus

[Stephen Boyd]

This is one small chunk of work related to DT overlays for expansion
boards. It would be good to have a way to expose #<list>-cells types of
providers through a connector in a standard way. So we introduce a way
to make "nexus" nodes for these types of properties to remap the consumer
number space to the other side of the connector's number space. It's
basically a copy of the interrupt nexus implementation, but without
the address space matching design and interrupt-parent walking.

The first patch implements a generic method to do this, and the second patch
adds a unit test for it. The third patch is more of an example than anything
else. It shows how we would modify frameworks to use the new API.

I wasn't certain what more to document, but I

Changes since v1:
 * Addition of optional pass-thru parameter
 * Reduction of strings passed to 1 instead of 3 (or 4 now)
 * Updated gpio patch for the new function signature
 * Updated test-case for new funciton signature and pass-thru parameter
 * Updated kernel-doc to be correct and highlighted difference between
   this API and of_parse_phandle_with_args()

Stephen Boyd (3):
  of: Support parsing phandle argument lists through a nexus node
  of: unittest: Add phandle remapping test
  gpio: Support gpio nexus dt bindings

 drivers/gpio/gpiolib-of.c                   |   4 +-
 drivers/of/base.c                           | 186 ++++++++++++++++++++++++++++
 drivers/of/unittest-data/testcases.dts      |  11 ++
 drivers/of/unittest-data/tests-phandle.dtsi |  25 ++++
 drivers/of/unittest.c                       | 120 ++++++++++++++++++
 include/linux/of.h                          |  12 ++
 6 files changed, 356 insertions(+), 2 deletions(-)

-- 
2.10.0.297.gf6727b0

[PATCHv2 0/3] OF phandle nexus support + GPIO nexus

[Stephen Boyd]

This is one small chunk of work related to DT overlays for expansion
boards. It would be good to have a way to expose #<list>-cells types of
providers through a connector in a standard way. So we introduce a way
to make "nexus" nodes for these types of properties to remap the consumer
number space to the other side of the connector's number space. It's
basically a copy of the interrupt nexus implementation, but without
the address space matching design and interrupt-parent walking.

The first patch implements a generic method to do this, and the second patch
adds a unit test for it. The third patch is more of an example than anything
else. It shows how we would modify frameworks to use the new API.

I wasn't certain what more to document, but I

Changes since v1:
 * Addition of optional pass-thru parameter
 * Reduction of strings passed to 1 instead of 3 (or 4 now)
 * Updated gpio patch for the new function signature
 * Updated test-case for new funciton signature and pass-thru parameter
 * Updated kernel-doc to be correct and highlighted difference between
   this API and of_parse_phandle_with_args()

Stephen Boyd (3):
  of: Support parsing phandle argument lists through a nexus node
  of: unittest: Add phandle remapping test
  gpio: Support gpio nexus dt bindings

 drivers/gpio/gpiolib-of.c                   |   4 +-
 drivers/of/base.c                           | 186 ++++++++++++++++++++++++++++
 drivers/of/unittest-data/testcases.dts      |  11 ++
 drivers/of/unittest-data/tests-phandle.dtsi |  25 ++++
 drivers/of/unittest.c                       | 120 ++++++++++++++++++
 include/linux/of.h                          |  12 ++
 6 files changed, 356 insertions(+), 2 deletions(-)

-- 
2.10.0.297.gf6727b0

[PATCH v2 1/3] of: Support parsing phandle argument lists through a nexus node

[Stephen Boyd]

Platforms like 96boards have a standardized connector/expansion
slot that exposes signals like GPIOs to expansion boards in an
SoC agnostic way. We'd like the DT overlays for the expansion
boards to be written once without knowledge of the SoC on the
other side of the connector. This avoids the unscalable
combinatorial explosion of a different DT overlay for each
expansion board and SoC pair.

We need a way to describe the GPIOs routed through the connector
in an SoC agnostic way. Let's introduce nexus property parsing
into the OF core to do this. This is largely based on the
interrupt nexus support we already have. This allows us to remap
a phandle list in a consumer node (e.g. reset-gpios) through a
connector in a generic way (e.g. via gpio-map). Do this in a
generic routine so that we can remap any sort of variable length
phandle list.

Taking GPIOs as an example, the connector would be a GPIO nexus,
supporting the remapping of a GPIO specifier space to multiple
GPIO providers on the SoC. DT would look as shown below, where
'soc_gpio1' and 'soc_gpio2' are inside the SoC, 'connector' is an
expansion port where boards can be plugged in, and
'expansion_device' is a device on the expansion board.

	soc {
		soc_gpio1: gpio-controller1 {
			#gpio-cells = <2>;
		};

		soc_gpio2: gpio-controller2 {
			#gpio-cells = <2>;
		};
	};

	connector: connector {
		#gpio-cells = <2>;
		gpio-map = <0 0 &soc_gpio1 1 0>,
			   <1 0 &soc_gpio2 4 0>,
			   <2 0 &soc_gpio1 3 0>,
			   <3 0 &soc_gpio2 2 0>;
		gpio-map-mask = <0xf 0x0>;
		gpio-map-pass-thru = <0x0 0x1>
	};

	expansion_device {
		reset-gpios = <&connector 2 GPIO_ACTIVE_LOW>;
	};

The GPIO core would use of_parse_phandle_with_args_map() instead
of of_parse_phandle_with_args() and arrive at the same type of
result, a phandle and argument list. The difference is that the
phandle and arguments will be remapped through the nexus node to
the underlying SoC GPIO controller node. In the example above,
we would remap 'reset-gpios' from <&connector 2 GPIO_ACTIVE_LOW>
to <&soc_gpio1 3 GPIO_ACTIVE_LOW>.

Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
---
 drivers/of/base.c  | 186 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h |  12 ++++
 2 files changed, 198 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index d4bea3c797d6..277a81ff0479 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1775,6 +1775,192 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
 EXPORT_SYMBOL(of_parse_phandle_with_args);
 
 /**
+ * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
+ * @np:		pointer to a device tree node containing a list
+ * @list_name:	property name that contains a list
+ * @stem_name:	stem of property names that specify phandles' arguments count
+ * @index:	index of a phandle to parse out
+ * @out_args:	optional pointer to output arguments structure (will be filled)
+ *
+ * This function is useful to parse lists of phandles and their arguments.
+ * Returns 0 on success and fills out_args, on error returns appropriate errno
+ * value. The difference between this function and of_parse_phandle_with_args()
+ * is that this API remaps a phandle if the node the phandle points to has
+ * a <@stem_name>-map property.
+ *
+ * Caller is responsible to call of_node_put() on the returned out_args->np
+ * pointer.
+ *
+ * Example:
+ *
+ * phandle1: node1 {
+ *	#list-cells = <2>;
+ * }
+ *
+ * phandle2: node2 {
+ *	#list-cells = <1>;
+ * }
+ *
+ * phandle3: node3 {
+ * 	#list-cells = <1>;
+ * 	list-map = <0 &phandle2 3>,
+ * 		   <1 &phandle2 2>,
+ * 		   <2 &phandle1 5 1>;
+ *	list-map-mask = <0x3>;
+ * };
+ *
+ * node4 {
+ *	list = <&phandle1 1 2 &phandle3 0>;
+ * }
+ *
+ * To get a device_node of the `node2' node you may call this:
+ * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
+ */
+int of_parse_phandle_with_args_map(const struct device_node *np,
+				   const char *list_name,
+				   const char *stem_name,
+				   int index, struct of_phandle_args *out_args)
+{
+	char *cells_name, *map_name = NULL, *mask_name = NULL;
+	char *pass_name = NULL;
+	struct device_node *cur, *new = NULL;
+	const __be32 *map, *mask, *pass, *tmp;
+	const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
+	const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
+	__be32 initial_match_array[MAX_PHANDLE_ARGS];
+	const __be32 *match_array = initial_match_array;
+	int i, ret, map_len, match;
+	u32 list_size, new_size;
+
+	if (index < 0)
+		return -EINVAL;
+
+	cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
+	if (!cells_name)
+		return -ENOMEM;
+
+	ret = -ENOMEM;
+	map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
+	if (!map_name)
+		goto free;
+
+	mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
+	if (!mask_name)
+		goto free;
+
+	pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
+	if (!pass_name)
+		goto free;
+
+	ret = __of_parse_phandle_with_args(np, list_name, cells_name, 0, index,
+					   out_args);
+	if (ret)
+		goto free;
+
+	/* Get the #<list>-cells property */
+	cur = out_args->np;
+	ret = of_property_read_u32(cur, cells_name, &list_size);
+	if (ret < 0)
+		goto put;
+
+	/* Precalculate the match array - this simplifies match loop */
+	for (i = 0; i < list_size; i++)
+		initial_match_array[i] = cpu_to_be32(out_args->args[i]);
+
+	ret = -EINVAL;
+	while (cur) {
+		/* Get the <list>-map property */
+		map = of_get_property(cur, map_name, &map_len);
+		if (!map) {
+			ret = 0;
+			goto free;
+		}
+		map_len /= sizeof(u32);
+
+		/* Get the <list>-map-mask property (optional) */
+		mask = of_get_property(cur, mask_name, NULL);
+		if (!mask)
+			mask = dummy_mask;
+		/* Iterate through <list>-map property */
+		match = 0;
+		while (map_len > (list_size + 1) && !match) {
+			/* Compare specifiers */
+			match = 1;
+			for (i = 0; i < list_size; i++, map_len--)
+				match &= !((match_array[i] ^ *map++) & mask[i]);
+
+			of_node_put(new);
+			new = of_find_node_by_phandle(be32_to_cpup(map));
+			map++;
+			map_len--;
+
+			/* Check if not found */
+			if (!new)
+				goto put;
+
+			if (!of_device_is_available(new))
+				match = 0;
+
+			tmp = of_get_property(new, cells_name, NULL);
+			if (!tmp)
+				goto put;
+
+			new_size = be32_to_cpu(*tmp);
+
+			/* Check for malformed properties */
+			if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
+				goto put;
+			if (map_len < new_size)
+				goto put;
+
+			/* Move forward by new node's #<list>-cells amount */
+			map += new_size;
+			map_len -= new_size;
+		}
+		if (!match)
+			goto put;
+
+		/* Get the <list>-map-pass-thru property (optional) */
+		pass = of_get_property(cur, pass_name, NULL);
+		if (!pass)
+			pass = dummy_pass;
+
+		/*
+		 * Successfully parsed a <list>-map translation; copy new
+		 * specifier into the out_args structure, keeping the
+		 * bits specified in <list>-map-pass-thru.
+		 */
+		match_array = map - new_size;
+		for (i = 0; i < new_size; i++) {
+			__be32 val = *(map - new_size + i);
+
+			if (i < list_size) {
+				val &= ~pass[i];
+				val |= cpu_to_be32(out_args->args[i]) & pass[i];
+			}
+
+			out_args->args[i] = be32_to_cpu(val);
+		}
+		out_args->args_count = list_size = new_size;
+		/* Iterate again with new provider */
+		out_args->np = new;
+		of_node_put(cur);
+		cur = new;
+	}
+put:
+	of_node_put(cur);
+	of_node_put(new);
+free:
+	kfree(mask_name);
+	kfree(map_name);
+	kfree(cells_name);
+	kfree(pass_name);
+
+	return ret;
+}
+EXPORT_SYMBOL(of_parse_phandle_with_args_map);
+
+/**
  * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
  * @np:		pointer to a device tree node containing a list
  * @list_name:	property name that contains a list
diff --git a/include/linux/of.h b/include/linux/of.h
index 011c4984cdf5..f22d4a83ca07 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -344,6 +344,9 @@ extern struct device_node *of_parse_phandle(const struct device_node *np,
 extern int of_parse_phandle_with_args(const struct device_node *np,
 	const char *list_name, const char *cells_name, int index,
 	struct of_phandle_args *out_args);
+extern int of_parse_phandle_with_args_map(const struct device_node *np,
+	const char *list_name, const char *stem_name, int index,
+	struct of_phandle_args *out_args);
 extern int of_parse_phandle_with_fixed_args(const struct device_node *np,
 	const char *list_name, int cells_count, int index,
 	struct of_phandle_args *out_args);
@@ -738,6 +741,15 @@ static inline int of_parse_phandle_with_args(const struct device_node *np,
 	return -ENOSYS;
 }
 
+static inline int of_parse_phandle_with_args_map(const struct device_node *np,
+						 const char *list_name,
+						 const char *stem_name,
+						 int index,
+						 struct of_phandle_args *out_args)
+{
+	return -ENOSYS;
+}
+
 static inline int of_parse_phandle_with_fixed_args(const struct device_node *np,
 	const char *list_name, int cells_count, int index,
 	struct of_phandle_args *out_args)
-- 
2.10.0.297.gf6727b0

[PATCH v2 1/3] of: Support parsing phandle argument lists through a nexus node

[Stephen Boyd]

Platforms like 96boards have a standardized connector/expansion
slot that exposes signals like GPIOs to expansion boards in an
SoC agnostic way. We'd like the DT overlays for the expansion
boards to be written once without knowledge of the SoC on the
other side of the connector. This avoids the unscalable
combinatorial explosion of a different DT overlay for each
expansion board and SoC pair.

We need a way to describe the GPIOs routed through the connector
in an SoC agnostic way. Let's introduce nexus property parsing
into the OF core to do this. This is largely based on the
interrupt nexus support we already have. This allows us to remap
a phandle list in a consumer node (e.g. reset-gpios) through a
connector in a generic way (e.g. via gpio-map). Do this in a
generic routine so that we can remap any sort of variable length
phandle list.

Taking GPIOs as an example, the connector would be a GPIO nexus,
supporting the remapping of a GPIO specifier space to multiple
GPIO providers on the SoC. DT would look as shown below, where
'soc_gpio1' and 'soc_gpio2' are inside the SoC, 'connector' is an
expansion port where boards can be plugged in, and
'expansion_device' is a device on the expansion board.

	soc {
		soc_gpio1: gpio-controller1 {
			#gpio-cells = <2>;
		};

		soc_gpio2: gpio-controller2 {
			#gpio-cells = <2>;
		};
	};

	connector: connector {
		#gpio-cells = <2>;
		gpio-map = <0 0 &soc_gpio1 1 0>,
			   <1 0 &soc_gpio2 4 0>,
			   <2 0 &soc_gpio1 3 0>,
			   <3 0 &soc_gpio2 2 0>;
		gpio-map-mask = <0xf 0x0>;
		gpio-map-pass-thru = <0x0 0x1>
	};

	expansion_device {
		reset-gpios = <&connector 2 GPIO_ACTIVE_LOW>;
	};

The GPIO core would use of_parse_phandle_with_args_map() instead
of of_parse_phandle_with_args() and arrive at the same type of
result, a phandle and argument list. The difference is that the
phandle and arguments will be remapped through the nexus node to
the underlying SoC GPIO controller node. In the example above,
we would remap 'reset-gpios' from <&connector 2 GPIO_ACTIVE_LOW>
to <&soc_gpio1 3 GPIO_ACTIVE_LOW>.

Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
---
 drivers/of/base.c  | 186 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h |  12 ++++
 2 files changed, 198 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index d4bea3c797d6..277a81ff0479 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1775,6 +1775,192 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
 EXPORT_SYMBOL(of_parse_phandle_with_args);
 
 /**
+ * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
+ * @np:		pointer to a device tree node containing a list
+ * @list_name:	property name that contains a list
+ * @stem_name:	stem of property names that specify phandles' arguments count
+ * @index:	index of a phandle to parse out
+ * @out_args:	optional pointer to output arguments structure (will be filled)
+ *
+ * This function is useful to parse lists of phandles and their arguments.
+ * Returns 0 on success and fills out_args, on error returns appropriate errno
+ * value. The difference between this function and of_parse_phandle_with_args()
+ * is that this API remaps a phandle if the node the phandle points to has
+ * a <@stem_name>-map property.
+ *
+ * Caller is responsible to call of_node_put() on the returned out_args->np
+ * pointer.
+ *
+ * Example:
+ *
+ * phandle1: node1 {
+ *	#list-cells = <2>;
+ * }
+ *
+ * phandle2: node2 {
+ *	#list-cells = <1>;
+ * }
+ *
+ * phandle3: node3 {
+ * 	#list-cells = <1>;
+ * 	list-map = <0 &phandle2 3>,
+ * 		   <1 &phandle2 2>,
+ * 		   <2 &phandle1 5 1>;
+ *	list-map-mask = <0x3>;
+ * };
+ *
+ * node4 {
+ *	list = <&phandle1 1 2 &phandle3 0>;
+ * }
+ *
+ * To get a device_node of the `node2' node you may call this:
+ * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
+ */
+int of_parse_phandle_with_args_map(const struct device_node *np,
+				   const char *list_name,
+				   const char *stem_name,
+				   int index, struct of_phandle_args *out_args)
+{
+	char *cells_name, *map_name = NULL, *mask_name = NULL;
+	char *pass_name = NULL;
+	struct device_node *cur, *new = NULL;
+	const __be32 *map, *mask, *pass, *tmp;
+	const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
+	const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
+	__be32 initial_match_array[MAX_PHANDLE_ARGS];
+	const __be32 *match_array = initial_match_array;
+	int i, ret, map_len, match;
+	u32 list_size, new_size;
+
+	if (index < 0)
+		return -EINVAL;
+
+	cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
+	if (!cells_name)
+		return -ENOMEM;
+
+	ret = -ENOMEM;
+	map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
+	if (!map_name)
+		goto free;
+
+	mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
+	if (!mask_name)
+		goto free;
+
+	pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
+	if (!pass_name)
+		goto free;
+
+	ret = __of_parse_phandle_with_args(np, list_name, cells_name, 0, index,
+					   out_args);
+	if (ret)
+		goto free;
+
+	/* Get the #<list>-cells property */
+	cur = out_args->np;
+	ret = of_property_read_u32(cur, cells_name, &list_size);
+	if (ret < 0)
+		goto put;
+
+	/* Precalculate the match array - this simplifies match loop */
+	for (i = 0; i < list_size; i++)
+		initial_match_array[i] = cpu_to_be32(out_args->args[i]);
+
+	ret = -EINVAL;
+	while (cur) {
+		/* Get the <list>-map property */
+		map = of_get_property(cur, map_name, &map_len);
+		if (!map) {
+			ret = 0;
+			goto free;
+		}
+		map_len /= sizeof(u32);
+
+		/* Get the <list>-map-mask property (optional) */
+		mask = of_get_property(cur, mask_name, NULL);
+		if (!mask)
+			mask = dummy_mask;
+		/* Iterate through <list>-map property */
+		match = 0;
+		while (map_len > (list_size + 1) && !match) {
+			/* Compare specifiers */
+			match = 1;
+			for (i = 0; i < list_size; i++, map_len--)
+				match &= !((match_array[i] ^ *map++) & mask[i]);
+
+			of_node_put(new);
+			new = of_find_node_by_phandle(be32_to_cpup(map));
+			map++;
+			map_len--;
+
+			/* Check if not found */
+			if (!new)
+				goto put;
+
+			if (!of_device_is_available(new))
+				match = 0;
+
+			tmp = of_get_property(new, cells_name, NULL);
+			if (!tmp)
+				goto put;
+
+			new_size = be32_to_cpu(*tmp);
+
+			/* Check for malformed properties */
+			if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
+				goto put;
+			if (map_len < new_size)
+				goto put;
+
+			/* Move forward by new node's #<list>-cells amount */
+			map += new_size;
+			map_len -= new_size;
+		}
+		if (!match)
+			goto put;
+
+		/* Get the <list>-map-pass-thru property (optional) */
+		pass = of_get_property(cur, pass_name, NULL);
+		if (!pass)
+			pass = dummy_pass;
+
+		/*
+		 * Successfully parsed a <list>-map translation; copy new
+		 * specifier into the out_args structure, keeping the
+		 * bits specified in <list>-map-pass-thru.
+		 */
+		match_array = map - new_size;
+		for (i = 0; i < new_size; i++) {
+			__be32 val = *(map - new_size + i);
+
+			if (i < list_size) {
+				val &= ~pass[i];
+				val |= cpu_to_be32(out_args->args[i]) & pass[i];
+			}
+
+			out_args->args[i] = be32_to_cpu(val);
+		}
+		out_args->args_count = list_size = new_size;
+		/* Iterate again with new provider */
+		out_args->np = new;
+		of_node_put(cur);
+		cur = new;
+	}
+put:
+	of_node_put(cur);
+	of_node_put(new);
+free:
+	kfree(mask_name);
+	kfree(map_name);
+	kfree(cells_name);
+	kfree(pass_name);
+
+	return ret;
+}
+EXPORT_SYMBOL(of_parse_phandle_with_args_map);
+
+/**
  * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
  * @np:		pointer to a device tree node containing a list
  * @list_name:	property name that contains a list
diff --git a/include/linux/of.h b/include/linux/of.h
index 011c4984cdf5..f22d4a83ca07 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -344,6 +344,9 @@ extern struct device_node *of_parse_phandle(const struct device_node *np,
 extern int of_parse_phandle_with_args(const struct device_node *np,
 	const char *list_name, const char *cells_name, int index,
 	struct of_phandle_args *out_args);
+extern int of_parse_phandle_with_args_map(const struct device_node *np,
+	const char *list_name, const char *stem_name, int index,
+	struct of_phandle_args *out_args);
 extern int of_parse_phandle_with_fixed_args(const struct device_node *np,
 	const char *list_name, int cells_count, int index,
 	struct of_phandle_args *out_args);
@@ -738,6 +741,15 @@ static inline int of_parse_phandle_with_args(const struct device_node *np,
 	return -ENOSYS;
 }
 
+static inline int of_parse_phandle_with_args_map(const struct device_node *np,
+						 const char *list_name,
+						 const char *stem_name,
+						 int index,
+						 struct of_phandle_args *out_args)
+{
+	return -ENOSYS;
+}
+
 static inline int of_parse_phandle_with_fixed_args(const struct device_node *np,
 	const char *list_name, int cells_count, int index,
 	struct of_phandle_args *out_args)
-- 
2.10.0.297.gf6727b0

[PATCH v2 1/3] of: Support parsing phandle argument lists through a nexus node

[Stephen Boyd]

Platforms like 96boards have a standardized connector/expansion
slot that exposes signals like GPIOs to expansion boards in an
SoC agnostic way. We'd like the DT overlays for the expansion
boards to be written once without knowledge of the SoC on the
other side of the connector. This avoids the unscalable
combinatorial explosion of a different DT overlay for each
expansion board and SoC pair.

We need a way to describe the GPIOs routed through the connector
in an SoC agnostic way. Let's introduce nexus property parsing
into the OF core to do this. This is largely based on the
interrupt nexus support we already have. This allows us to remap
a phandle list in a consumer node (e.g. reset-gpios) through a
connector in a generic way (e.g. via gpio-map). Do this in a
generic routine so that we can remap any sort of variable length
phandle list.

Taking GPIOs as an example, the connector would be a GPIO nexus,
supporting the remapping of a GPIO specifier space to multiple
GPIO providers on the SoC. DT would look as shown below, where
'soc_gpio1' and 'soc_gpio2' are inside the SoC, 'connector' is an
expansion port where boards can be plugged in, and
'expansion_device' is a device on the expansion board.

	soc {
		soc_gpio1: gpio-controller1 {
			#gpio-cells = <2>;
		};

		soc_gpio2: gpio-controller2 {
			#gpio-cells = <2>;
		};
	};

	connector: connector {
		#gpio-cells = <2>;
		gpio-map = <0 0 &soc_gpio1 1 0>,
			   <1 0 &soc_gpio2 4 0>,
			   <2 0 &soc_gpio1 3 0>,
			   <3 0 &soc_gpio2 2 0>;
		gpio-map-mask = <0xf 0x0>;
		gpio-map-pass-thru = <0x0 0x1>
	};

	expansion_device {
		reset-gpios = <&connector 2 GPIO_ACTIVE_LOW>;
	};

The GPIO core would use of_parse_phandle_with_args_map() instead
of of_parse_phandle_with_args() and arrive at the same type of
result, a phandle and argument list. The difference is that the
phandle and arguments will be remapped through the nexus node to
the underlying SoC GPIO controller node. In the example above,
we would remap 'reset-gpios' from <&connector 2 GPIO_ACTIVE_LOW>
to <&soc_gpio1 3 GPIO_ACTIVE_LOW>.

Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
---
 drivers/of/base.c  | 186 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h |  12 ++++
 2 files changed, 198 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index d4bea3c797d6..277a81ff0479 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1775,6 +1775,192 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
 EXPORT_SYMBOL(of_parse_phandle_with_args);
 
 /**
+ * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
+ * @np:		pointer to a device tree node containing a list
+ * @list_name:	property name that contains a list
+ * @stem_name:	stem of property names that specify phandles' arguments count
+ * @index:	index of a phandle to parse out
+ * @out_args:	optional pointer to output arguments structure (will be filled)
+ *
+ * This function is useful to parse lists of phandles and their arguments.
+ * Returns 0 on success and fills out_args, on error returns appropriate errno
+ * value. The difference between this function and of_parse_phandle_with_args()
+ * is that this API remaps a phandle if the node the phandle points to has
+ * a <@stem_name>-map property.
+ *
+ * Caller is responsible to call of_node_put() on the returned out_args->np
+ * pointer.
+ *
+ * Example:
+ *
+ * phandle1: node1 {
+ *	#list-cells = <2>;
+ * }
+ *
+ * phandle2: node2 {
+ *	#list-cells = <1>;
+ * }
+ *
+ * phandle3: node3 {
+ * 	#list-cells = <1>;
+ * 	list-map = <0 &phandle2 3>,
+ * 		   <1 &phandle2 2>,
+ * 		   <2 &phandle1 5 1>;
+ *	list-map-mask = <0x3>;
+ * };
+ *
+ * node4 {
+ *	list = <&phandle1 1 2 &phandle3 0>;
+ * }
+ *
+ * To get a device_node of the `node2' node you may call this:
+ * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
+ */
+int of_parse_phandle_with_args_map(const struct device_node *np,
+				   const char *list_name,
+				   const char *stem_name,
+				   int index, struct of_phandle_args *out_args)
+{
+	char *cells_name, *map_name = NULL, *mask_name = NULL;
+	char *pass_name = NULL;
+	struct device_node *cur, *new = NULL;
+	const __be32 *map, *mask, *pass, *tmp;
+	const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
+	const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
+	__be32 initial_match_array[MAX_PHANDLE_ARGS];
+	const __be32 *match_array = initial_match_array;
+	int i, ret, map_len, match;
+	u32 list_size, new_size;
+
+	if (index < 0)
+		return -EINVAL;
+
+	cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
+	if (!cells_name)
+		return -ENOMEM;
+
+	ret = -ENOMEM;
+	map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
+	if (!map_name)
+		goto free;
+
+	mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
+	if (!mask_name)
+		goto free;
+
+	pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
+	if (!pass_name)
+		goto free;
+
+	ret = __of_parse_phandle_with_args(np, list_name, cells_name, 0, index,
+					   out_args);
+	if (ret)
+		goto free;
+
+	/* Get the #<list>-cells property */
+	cur = out_args->np;
+	ret = of_property_read_u32(cur, cells_name, &list_size);
+	if (ret < 0)
+		goto put;
+
+	/* Precalculate the match array - this simplifies match loop */
+	for (i = 0; i < list_size; i++)
+		initial_match_array[i] = cpu_to_be32(out_args->args[i]);
+
+	ret = -EINVAL;
+	while (cur) {
+		/* Get the <list>-map property */
+		map = of_get_property(cur, map_name, &map_len);
+		if (!map) {
+			ret = 0;
+			goto free;
+		}
+		map_len /= sizeof(u32);
+
+		/* Get the <list>-map-mask property (optional) */
+		mask = of_get_property(cur, mask_name, NULL);
+		if (!mask)
+			mask = dummy_mask;
+		/* Iterate through <list>-map property */
+		match = 0;
+		while (map_len > (list_size + 1) && !match) {
+			/* Compare specifiers */
+			match = 1;
+			for (i = 0; i < list_size; i++, map_len--)
+				match &= !((match_array[i] ^ *map++) & mask[i]);
+
+			of_node_put(new);
+			new = of_find_node_by_phandle(be32_to_cpup(map));
+			map++;
+			map_len--;
+
+			/* Check if not found */
+			if (!new)
+				goto put;
+
+			if (!of_device_is_available(new))
+				match = 0;
+
+			tmp = of_get_property(new, cells_name, NULL);
+			if (!tmp)
+				goto put;
+
+			new_size = be32_to_cpu(*tmp);
+
+			/* Check for malformed properties */
+			if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
+				goto put;
+			if (map_len < new_size)
+				goto put;
+
+			/* Move forward by new node's #<list>-cells amount */
+			map += new_size;
+			map_len -= new_size;
+		}
+		if (!match)
+			goto put;
+
+		/* Get the <list>-map-pass-thru property (optional) */
+		pass = of_get_property(cur, pass_name, NULL);
+		if (!pass)
+			pass = dummy_pass;
+
+		/*
+		 * Successfully parsed a <list>-map translation; copy new
+		 * specifier into the out_args structure, keeping the
+		 * bits specified in <list>-map-pass-thru.
+		 */
+		match_array = map - new_size;
+		for (i = 0; i < new_size; i++) {
+			__be32 val = *(map - new_size + i);
+
+			if (i < list_size) {
+				val &= ~pass[i];
+				val |= cpu_to_be32(out_args->args[i]) & pass[i];
+			}
+
+			out_args->args[i] = be32_to_cpu(val);
+		}
+		out_args->args_count = list_size = new_size;
+		/* Iterate again with new provider */
+		out_args->np = new;
+		of_node_put(cur);
+		cur = new;
+	}
+put:
+	of_node_put(cur);
+	of_node_put(new);
+free:
+	kfree(mask_name);
+	kfree(map_name);
+	kfree(cells_name);
+	kfree(pass_name);
+
+	return ret;
+}
+EXPORT_SYMBOL(of_parse_phandle_with_args_map);
+
+/**
  * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
  * @np:		pointer to a device tree node containing a list
  * @list_name:	property name that contains a list
diff --git a/include/linux/of.h b/include/linux/of.h
index 011c4984cdf5..f22d4a83ca07 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -344,6 +344,9 @@ extern struct device_node *of_parse_phandle(const struct device_node *np,
 extern int of_parse_phandle_with_args(const struct device_node *np,
 	const char *list_name, const char *cells_name, int index,
 	struct of_phandle_args *out_args);
+extern int of_parse_phandle_with_args_map(const struct device_node *np,
+	const char *list_name, const char *stem_name, int index,
+	struct of_phandle_args *out_args);
 extern int of_parse_phandle_with_fixed_args(const struct device_node *np,
 	const char *list_name, int cells_count, int index,
 	struct of_phandle_args *out_args);
@@ -738,6 +741,15 @@ static inline int of_parse_phandle_with_args(const struct device_node *np,
 	return -ENOSYS;
 }
 
+static inline int of_parse_phandle_with_args_map(const struct device_node *np,
+						 const char *list_name,
+						 const char *stem_name,
+						 int index,
+						 struct of_phandle_args *out_args)
+{
+	return -ENOSYS;
+}
+
 static inline int of_parse_phandle_with_fixed_args(const struct device_node *np,
 	const char *list_name, int cells_count, int index,
 	struct of_phandle_args *out_args)
-- 
2.10.0.297.gf6727b0

[PATCH v2 2/3] of: unittest: Add phandle remapping test

[Stephen Boyd]

Test the functionality of of_parse_phandle_with_args_map().

Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
---
 drivers/of/unittest-data/testcases.dts      |  11 +++
 drivers/of/unittest-data/tests-phandle.dtsi |  25 ++++++
 drivers/of/unittest.c                       | 120 ++++++++++++++++++++++++++++
 3 files changed, 156 insertions(+)

diff --git a/drivers/of/unittest-data/testcases.dts b/drivers/of/unittest-data/testcases.dts
index 12f7c3d649c8..173b96f39cd0 100644
--- a/drivers/of/unittest-data/testcases.dts
+++ b/drivers/of/unittest-data/testcases.dts
@@ -26,12 +26,23 @@
 / { __local_fixups__ {
 	testcase-data {
 		phandle-tests {
+			provider4 {
+				phandle-map = <0x00000008 0x00000018
+					       0x00000024 0x0000003c
+					       0x00000050 0x00000064>;
+			};
 			consumer-a {
 				phandle-list = <0x00000000 0x00000008
 						0x00000018 0x00000028
 						0x00000034 0x00000038>;
 				phandle-list-bad-args = <0x00000000 0x0000000c>;
 			};
+			consumer-b {
+				phandle-list = <0x00000000 0x00000008
+						0x00000018 0x00000024
+						0x00000030 0x00000034>;
+				phandle-list-bad-args = <0x00000000 0x0000000c>;
+			};
 		};
 		interrupts {
 			intmap0 {
diff --git a/drivers/of/unittest-data/tests-phandle.dtsi b/drivers/of/unittest-data/tests-phandle.dtsi
index 5b1527e8a7fb..59e297f497d1 100644
--- a/drivers/of/unittest-data/tests-phandle.dtsi
+++ b/drivers/of/unittest-data/tests-phandle.dtsi
@@ -25,6 +25,18 @@
 				#phandle-cells = <3>;
 			};
 
+			provider4: provider4 {
+				#phandle-cells = <2>;
+				phandle-map = <0 1 &provider1 3>,
+					      <4 0 &provider0>,
+					      <16 5 &provider3 3 5 0>,
+					      <200 8 &provider2 23 6>,
+					      <19 0 &provider2 15 0>,
+					      <2 3 &provider3 2 5 3>;
+				phandle-map-mask = <0xff 0xf>;
+				phandle-map-pass-thru = <0x0 0xf0>;
+			};
+
 			consumer-a {
 				phandle-list =	<&provider1 1>,
 						<&provider2 2 0>,
@@ -43,6 +55,19 @@
 				unterminated-string = [40 41 42 43];
 				unterminated-string-list = "first", "second", [40 41 42 43];
 			};
+
+			consumer-b {
+				phandle-list =	<&provider1 1>,
+						<&provider4 2 3>,
+						<0>,
+						<&provider4 4 0x100>,
+						<&provider4 0 0x61>,
+						<&provider0>,
+						<&provider4 19 0x20>;
+				phandle-list-bad-phandle = <12345678 0 0>;
+				phandle-list-bad-args = <&provider2 1 0>,
+							<&provider4 0>;
+			};
 		};
 	};
 };
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 53c83d66eb7e..5baa40d0d83b 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -386,6 +386,125 @@ static void __init of_unittest_parse_phandle_with_args(void)
 	unittest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);
 }
 
+static void __init of_unittest_parse_phandle_with_args_map(void)
+{
+	struct device_node *np, *p0, *p1, *p2, *p3;
+	struct of_phandle_args args;
+	int i, rc;
+
+	np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-b");
+	if (!np) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	p0 = of_find_node_by_path("/testcase-data/phandle-tests/provider0");
+	if (!p0) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	p1 = of_find_node_by_path("/testcase-data/phandle-tests/provider1");
+	if (!p1) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	p2 = of_find_node_by_path("/testcase-data/phandle-tests/provider2");
+	if (!p2) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	p3 = of_find_node_by_path("/testcase-data/phandle-tests/provider3");
+	if (!p3) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	rc = of_count_phandle_with_args(np, "phandle-list", "#phandle-cells");
+	unittest(rc == 7, "of_count_phandle_with_args() returned %i, expected 7\n", rc);
+
+	for (i = 0; i < 8; i++) {
+		bool passed = true;
+
+		rc = of_parse_phandle_with_args_map(np, "phandle-list",
+						    "phandle", i, &args);
+
+		/* Test the values from tests-phandle.dtsi */
+		switch (i) {
+		case 0:
+			passed &= !rc;
+			passed &= (args.np == p1);
+			passed &= (args.args_count == 1);
+			passed &= (args.args[0] == 1);
+			break;
+		case 1:
+			passed &= !rc;
+			passed &= (args.np == p3);
+			passed &= (args.args_count == 3);
+			passed &= (args.args[0] == 2);
+			passed &= (args.args[1] == 5);
+			passed &= (args.args[2] == 3);
+			break;
+		case 2:
+			passed &= (rc == -ENOENT);
+			break;
+		case 3:
+			passed &= !rc;
+			passed &= (args.np == p0);
+			passed &= (args.args_count == 0);
+			break;
+		case 4:
+			passed &= !rc;
+			passed &= (args.np == p1);
+			passed &= (args.args_count == 1);
+			passed &= (args.args[0] == 3);
+			break;
+		case 5:
+			passed &= !rc;
+			passed &= (args.np == p0);
+			passed &= (args.args_count == 0);
+			break;
+		case 6:
+			passed &= !rc;
+			passed &= (args.np == p2);
+			passed &= (args.args_count == 2);
+			passed &= (args.args[0] == 15);
+			passed &= (args.args[1] == 0x20);
+			break;
+		case 7:
+			passed &= (rc == -ENOENT);
+			break;
+		default:
+			passed = false;
+		}
+
+		unittest(passed, "index %i - data error on node %s rc=%i\n",
+			 i, args.np->full_name, rc);
+	}
+
+	/* Check for missing list property */
+	rc = of_parse_phandle_with_args_map(np, "phandle-list-missing",
+					    "phandle", 0, &args);
+	unittest(rc == -ENOENT, "expected:%i got:%i\n", -ENOENT, rc);
+
+	/* Check for missing cells,map,mask property */
+	rc = of_parse_phandle_with_args_map(np, "phandle-list",
+					    "phandle-missing", 0, &args);
+	unittest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);
+
+	/* Check for bad phandle in list */
+	rc = of_parse_phandle_with_args_map(np, "phandle-list-bad-phandle",
+					    "phandle", 0, &args);
+	unittest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);
+
+	/* Check for incorrectly formed argument list */
+	rc = of_parse_phandle_with_args_map(np, "phandle-list-bad-args",
+					    "phandle", 1, &args);
+	unittest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);
+}
+
 static void __init of_unittest_property_string(void)
 {
 	const char *strings[4];
@@ -1951,6 +2070,7 @@ static int __init of_unittest(void)
 	of_unittest_find_node_by_name();
 	of_unittest_dynamic();
 	of_unittest_parse_phandle_with_args();
+	of_unittest_parse_phandle_with_args_map();
 	of_unittest_property_string();
 	of_unittest_property_copy();
 	of_unittest_changeset();
-- 
2.10.0.297.gf6727b0

[PATCH v2 2/3] of: unittest: Add phandle remapping test

[Stephen Boyd]

Test the functionality of of_parse_phandle_with_args_map().

Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
---
 drivers/of/unittest-data/testcases.dts      |  11 +++
 drivers/of/unittest-data/tests-phandle.dtsi |  25 ++++++
 drivers/of/unittest.c                       | 120 ++++++++++++++++++++++++++++
 3 files changed, 156 insertions(+)

diff --git a/drivers/of/unittest-data/testcases.dts b/drivers/of/unittest-data/testcases.dts
index 12f7c3d649c8..173b96f39cd0 100644
--- a/drivers/of/unittest-data/testcases.dts
+++ b/drivers/of/unittest-data/testcases.dts
@@ -26,12 +26,23 @@
 / { __local_fixups__ {
 	testcase-data {
 		phandle-tests {
+			provider4 {
+				phandle-map = <0x00000008 0x00000018
+					       0x00000024 0x0000003c
+					       0x00000050 0x00000064>;
+			};
 			consumer-a {
 				phandle-list = <0x00000000 0x00000008
 						0x00000018 0x00000028
 						0x00000034 0x00000038>;
 				phandle-list-bad-args = <0x00000000 0x0000000c>;
 			};
+			consumer-b {
+				phandle-list = <0x00000000 0x00000008
+						0x00000018 0x00000024
+						0x00000030 0x00000034>;
+				phandle-list-bad-args = <0x00000000 0x0000000c>;
+			};
 		};
 		interrupts {
 			intmap0 {
diff --git a/drivers/of/unittest-data/tests-phandle.dtsi b/drivers/of/unittest-data/tests-phandle.dtsi
index 5b1527e8a7fb..59e297f497d1 100644
--- a/drivers/of/unittest-data/tests-phandle.dtsi
+++ b/drivers/of/unittest-data/tests-phandle.dtsi
@@ -25,6 +25,18 @@
 				#phandle-cells = <3>;
 			};
 
+			provider4: provider4 {
+				#phandle-cells = <2>;
+				phandle-map = <0 1 &provider1 3>,
+					      <4 0 &provider0>,
+					      <16 5 &provider3 3 5 0>,
+					      <200 8 &provider2 23 6>,
+					      <19 0 &provider2 15 0>,
+					      <2 3 &provider3 2 5 3>;
+				phandle-map-mask = <0xff 0xf>;
+				phandle-map-pass-thru = <0x0 0xf0>;
+			};
+
 			consumer-a {
 				phandle-list =	<&provider1 1>,
 						<&provider2 2 0>,
@@ -43,6 +55,19 @@
 				unterminated-string = [40 41 42 43];
 				unterminated-string-list = "first", "second", [40 41 42 43];
 			};
+
+			consumer-b {
+				phandle-list =	<&provider1 1>,
+						<&provider4 2 3>,
+						<0>,
+						<&provider4 4 0x100>,
+						<&provider4 0 0x61>,
+						<&provider0>,
+						<&provider4 19 0x20>;
+				phandle-list-bad-phandle = <12345678 0 0>;
+				phandle-list-bad-args = <&provider2 1 0>,
+							<&provider4 0>;
+			};
 		};
 	};
 };
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 53c83d66eb7e..5baa40d0d83b 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -386,6 +386,125 @@ static void __init of_unittest_parse_phandle_with_args(void)
 	unittest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);
 }
 
+static void __init of_unittest_parse_phandle_with_args_map(void)
+{
+	struct device_node *np, *p0, *p1, *p2, *p3;
+	struct of_phandle_args args;
+	int i, rc;
+
+	np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-b");
+	if (!np) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	p0 = of_find_node_by_path("/testcase-data/phandle-tests/provider0");
+	if (!p0) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	p1 = of_find_node_by_path("/testcase-data/phandle-tests/provider1");
+	if (!p1) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	p2 = of_find_node_by_path("/testcase-data/phandle-tests/provider2");
+	if (!p2) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	p3 = of_find_node_by_path("/testcase-data/phandle-tests/provider3");
+	if (!p3) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	rc = of_count_phandle_with_args(np, "phandle-list", "#phandle-cells");
+	unittest(rc == 7, "of_count_phandle_with_args() returned %i, expected 7\n", rc);
+
+	for (i = 0; i < 8; i++) {
+		bool passed = true;
+
+		rc = of_parse_phandle_with_args_map(np, "phandle-list",
+						    "phandle", i, &args);
+
+		/* Test the values from tests-phandle.dtsi */
+		switch (i) {
+		case 0:
+			passed &= !rc;
+			passed &= (args.np == p1);
+			passed &= (args.args_count == 1);
+			passed &= (args.args[0] == 1);
+			break;
+		case 1:
+			passed &= !rc;
+			passed &= (args.np == p3);
+			passed &= (args.args_count == 3);
+			passed &= (args.args[0] == 2);
+			passed &= (args.args[1] == 5);
+			passed &= (args.args[2] == 3);
+			break;
+		case 2:
+			passed &= (rc == -ENOENT);
+			break;
+		case 3:
+			passed &= !rc;
+			passed &= (args.np == p0);
+			passed &= (args.args_count == 0);
+			break;
+		case 4:
+			passed &= !rc;
+			passed &= (args.np == p1);
+			passed &= (args.args_count == 1);
+			passed &= (args.args[0] == 3);
+			break;
+		case 5:
+			passed &= !rc;
+			passed &= (args.np == p0);
+			passed &= (args.args_count == 0);
+			break;
+		case 6:
+			passed &= !rc;
+			passed &= (args.np == p2);
+			passed &= (args.args_count == 2);
+			passed &= (args.args[0] == 15);
+			passed &= (args.args[1] == 0x20);
+			break;
+		case 7:
+			passed &= (rc == -ENOENT);
+			break;
+		default:
+			passed = false;
+		}
+
+		unittest(passed, "index %i - data error on node %s rc=%i\n",
+			 i, args.np->full_name, rc);
+	}
+
+	/* Check for missing list property */
+	rc = of_parse_phandle_with_args_map(np, "phandle-list-missing",
+					    "phandle", 0, &args);
+	unittest(rc == -ENOENT, "expected:%i got:%i\n", -ENOENT, rc);
+
+	/* Check for missing cells,map,mask property */
+	rc = of_parse_phandle_with_args_map(np, "phandle-list",
+					    "phandle-missing", 0, &args);
+	unittest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);
+
+	/* Check for bad phandle in list */
+	rc = of_parse_phandle_with_args_map(np, "phandle-list-bad-phandle",
+					    "phandle", 0, &args);
+	unittest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);
+
+	/* Check for incorrectly formed argument list */
+	rc = of_parse_phandle_with_args_map(np, "phandle-list-bad-args",
+					    "phandle", 1, &args);
+	unittest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);
+}
+
 static void __init of_unittest_property_string(void)
 {
 	const char *strings[4];
@@ -1951,6 +2070,7 @@ static int __init of_unittest(void)
 	of_unittest_find_node_by_name();
 	of_unittest_dynamic();
 	of_unittest_parse_phandle_with_args();
+	of_unittest_parse_phandle_with_args_map();
 	of_unittest_property_string();
 	of_unittest_property_copy();
 	of_unittest_changeset();
-- 
2.10.0.297.gf6727b0

[PATCH v2 3/3] gpio: Support gpio nexus dt bindings

[Stephen Boyd]

Platforms like 96boards have a standardized connector/expansion
slot that exposes signals like GPIOs to expansion boards in an
SoC agnostic way. We'd like the DT overlays for the expansion
boards to be written once without knowledge of the SoC on the
other side of the connector. This avoids the unscalable
combinatorial explosion of a different DT overlay for each
expansion board and SoC pair.

Now that we have nexus support in the OF core let's change the
function call here that parses the phandle lists of gpios to use
the nexus variant. This allows us to remap phandles and their
arguments through any number of nexus nodes and end up with the
actual gpio provider being used.

Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
---
 drivers/gpio/gpiolib-of.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 92b185f19232..17bca36d4ebb 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -75,8 +75,8 @@ struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
 	struct gpio_desc *desc;
 	int ret;
 
-	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
-					 &gpiospec);
+	ret = of_parse_phandle_with_args_map(np, propname, "gpio", index,
+					     &gpiospec);
 	if (ret) {
 		pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
 			__func__, propname, np->full_name, index);
-- 
2.10.0.297.gf6727b0

[PATCH v2 3/3] gpio: Support gpio nexus dt bindings

[Stephen Boyd]

Platforms like 96boards have a standardized connector/expansion
slot that exposes signals like GPIOs to expansion boards in an
SoC agnostic way. We'd like the DT overlays for the expansion
boards to be written once without knowledge of the SoC on the
other side of the connector. This avoids the unscalable
combinatorial explosion of a different DT overlay for each
expansion board and SoC pair.

Now that we have nexus support in the OF core let's change the
function call here that parses the phandle lists of gpios to use
the nexus variant. This allows us to remap phandles and their
arguments through any number of nexus nodes and end up with the
actual gpio provider being used.

Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
---
 drivers/gpio/gpiolib-of.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 92b185f19232..17bca36d4ebb 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -75,8 +75,8 @@ struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
 	struct gpio_desc *desc;
 	int ret;
 
-	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
-					 &gpiospec);
+	ret = of_parse_phandle_with_args_map(np, propname, "gpio", index,
+					     &gpiospec);
 	if (ret) {
 		pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
 			__func__, propname, np->full_name, index);
-- 
2.10.0.297.gf6727b0

Re: [PATCH v2 3/3] gpio: Support gpio nexus dt bindings

[Linus Walleij]

On Wed, Jan 18, 2017 at 1:50 AM, Stephen Boyd <stephen.boyd@linaro.org> wrote:

> Platforms like 96boards have a standardized connector/expansion
> slot that exposes signals like GPIOs to expansion boards in an
> SoC agnostic way. We'd like the DT overlays for the expansion
> boards to be written once without knowledge of the SoC on the
> other side of the connector. This avoids the unscalable
> combinatorial explosion of a different DT overlay for each
> expansion board and SoC pair.
>
> Now that we have nexus support in the OF core let's change the
> function call here that parses the phandle lists of gpios to use
> the nexus variant. This allows us to remap phandles and their
> arguments through any number of nexus nodes and end up with the
> actual gpio provider being used.
>
> Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Mark Brown <broonie@kernel.org>
> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Provided that patches 1 & 2 go in reviewed and merged
by DT/device core people, they can merge this on top as well.

Yours,
Linus Walleij

Re: [PATCH v2 3/3] gpio: Support gpio nexus dt bindings

[Linus Walleij]

On Wed, Jan 18, 2017 at 1:50 AM, Stephen Boyd <stephen.boyd@linaro.org> wrote:

> Platforms like 96boards have a standardized connector/expansion
> slot that exposes signals like GPIOs to expansion boards in an
> SoC agnostic way. We'd like the DT overlays for the expansion
> boards to be written once without knowledge of the SoC on the
> other side of the connector. This avoids the unscalable
> combinatorial explosion of a different DT overlay for each
> expansion board and SoC pair.
>
> Now that we have nexus support in the OF core let's change the
> function call here that parses the phandle lists of gpios to use
> the nexus variant. This allows us to remap phandles and their
> arguments through any number of nexus nodes and end up with the
> actual gpio provider being used.
>
> Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Mark Brown <broonie@kernel.org>
> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Provided that patches 1 & 2 go in reviewed and merged
by DT/device core people, they can merge this on top as well.

Yours,
Linus Walleij

[PATCH v2 3/3] gpio: Support gpio nexus dt bindings

[Linus Walleij]

On Wed, Jan 18, 2017 at 1:50 AM, Stephen Boyd <stephen.boyd@linaro.org> wrote:

> Platforms like 96boards have a standardized connector/expansion
> slot that exposes signals like GPIOs to expansion boards in an
> SoC agnostic way. We'd like the DT overlays for the expansion
> boards to be written once without knowledge of the SoC on the
> other side of the connector. This avoids the unscalable
> combinatorial explosion of a different DT overlay for each
> expansion board and SoC pair.
>
> Now that we have nexus support in the OF core let's change the
> function call here that parses the phandle lists of gpios to use
> the nexus variant. This allows us to remap phandles and their
> arguments through any number of nexus nodes and end up with the
> actual gpio provider being used.
>
> Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Mark Brown <broonie@kernel.org>
> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Provided that patches 1 & 2 go in reviewed and merged
by DT/device core people, they can merge this on top as well.

Yours,
Linus Walleij

Re: [PATCH v2 1/3] of: Support parsing phandle argument lists through a nexus node

[Rob Herring]

On Tue, Jan 17, 2017 at 6:50 PM, Stephen Boyd <stephen.boyd@linaro.org> wrote:
> Platforms like 96boards have a standardized connector/expansion
> slot that exposes signals like GPIOs to expansion boards in an
> SoC agnostic way. We'd like the DT overlays for the expansion
> boards to be written once without knowledge of the SoC on the
> other side of the connector. This avoids the unscalable
> combinatorial explosion of a different DT overlay for each
> expansion board and SoC pair.
>
> We need a way to describe the GPIOs routed through the connector
> in an SoC agnostic way. Let's introduce nexus property parsing
> into the OF core to do this. This is largely based on the
> interrupt nexus support we already have. This allows us to remap
> a phandle list in a consumer node (e.g. reset-gpios) through a
> connector in a generic way (e.g. via gpio-map). Do this in a
> generic routine so that we can remap any sort of variable length
> phandle list.
>
> Taking GPIOs as an example, the connector would be a GPIO nexus,
> supporting the remapping of a GPIO specifier space to multiple
> GPIO providers on the SoC. DT would look as shown below, where
> 'soc_gpio1' and 'soc_gpio2' are inside the SoC, 'connector' is an
> expansion port where boards can be plugged in, and
> 'expansion_device' is a device on the expansion board.
>
>         soc {
>                 soc_gpio1: gpio-controller1 {
>                         #gpio-cells = <2>;
>                 };
>
>                 soc_gpio2: gpio-controller2 {
>                         #gpio-cells = <2>;
>                 };
>         };
>
>         connector: connector {
>                 #gpio-cells = <2>;
>                 gpio-map = <0 0 &soc_gpio1 1 0>,
>                            <1 0 &soc_gpio2 4 0>,
>                            <2 0 &soc_gpio1 3 0>,
>                            <3 0 &soc_gpio2 2 0>;
>                 gpio-map-mask = <0xf 0x0>;
>                 gpio-map-pass-thru = <0x0 0x1>
>         };
>
>         expansion_device {
>                 reset-gpios = <&connector 2 GPIO_ACTIVE_LOW>;
>         };

This all looks good to me. A few nits below.

>
> The GPIO core would use of_parse_phandle_with_args_map() instead
> of of_parse_phandle_with_args() and arrive at the same type of
> result, a phandle and argument list. The difference is that the
> phandle and arguments will be remapped through the nexus node to
> the underlying SoC GPIO controller node. In the example above,
> we would remap 'reset-gpios' from <&connector 2 GPIO_ACTIVE_LOW>
> to <&soc_gpio1 3 GPIO_ACTIVE_LOW>.
>
> Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Mark Brown <broonie@kernel.org>
> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
> ---
>  drivers/of/base.c  | 186 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/of.h |  12 ++++
>  2 files changed, 198 insertions(+)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index d4bea3c797d6..277a81ff0479 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -1775,6 +1775,192 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
>  EXPORT_SYMBOL(of_parse_phandle_with_args);
>
>  /**
> + * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
> + * @np:                pointer to a device tree node containing a list
> + * @list_name: property name that contains a list
> + * @stem_name: stem of property names that specify phandles' arguments count
> + * @index:     index of a phandle to parse out
> + * @out_args:  optional pointer to output arguments structure (will be filled)
> + *
> + * This function is useful to parse lists of phandles and their arguments.
> + * Returns 0 on success and fills out_args, on error returns appropriate errno
> + * value. The difference between this function and of_parse_phandle_with_args()
> + * is that this API remaps a phandle if the node the phandle points to has
> + * a <@stem_name>-map property.
> + *
> + * Caller is responsible to call of_node_put() on the returned out_args->np
> + * pointer.
> + *
> + * Example:
> + *
> + * phandle1: node1 {
> + *     #list-cells = <2>;
> + * }
> + *
> + * phandle2: node2 {
> + *     #list-cells = <1>;
> + * }
> + *
> + * phandle3: node3 {
> + *     #list-cells = <1>;
> + *     list-map = <0 &phandle2 3>,
> + *                <1 &phandle2 2>,
> + *                <2 &phandle1 5 1>;
> + *     list-map-mask = <0x3>;
> + * };
> + *
> + * node4 {
> + *     list = <&phandle1 1 2 &phandle3 0>;
> + * }
> + *
> + * To get a device_node of the `node2' node you may call this:
> + * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
> + */
> +int of_parse_phandle_with_args_map(const struct device_node *np,
> +                                  const char *list_name,
> +                                  const char *stem_name,
> +                                  int index, struct of_phandle_args *out_args)
> +{
> +       char *cells_name, *map_name = NULL, *mask_name = NULL;
> +       char *pass_name = NULL;
> +       struct device_node *cur, *new = NULL;
> +       const __be32 *map, *mask, *pass, *tmp;

> +       const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
> +       const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };

These could be static and save some stack space.

> +       __be32 initial_match_array[MAX_PHANDLE_ARGS];

We worked to get rid of this MAX_PHANDLE_ARGS limitation. I guess this
is fine as I don't think we'll do an IOMMU thru a connector which is
the main thing having long args list.

> +       const __be32 *match_array = initial_match_array;
> +       int i, ret, map_len, match;
> +       u32 list_size, new_size;
> +
> +       if (index < 0)
> +               return -EINVAL;
> +
> +       cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
> +       if (!cells_name)
> +               return -ENOMEM;
> +
> +       ret = -ENOMEM;
> +       map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
> +       if (!map_name)
> +               goto free;
> +
> +       mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
> +       if (!mask_name)
> +               goto free;
> +
> +       pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
> +       if (!pass_name)
> +               goto free;
> +
> +       ret = __of_parse_phandle_with_args(np, list_name, cells_name, 0, index,
> +                                          out_args);
> +       if (ret)
> +               goto free;
> +
> +       /* Get the #<list>-cells property */
> +       cur = out_args->np;
> +       ret = of_property_read_u32(cur, cells_name, &list_size);
> +       if (ret < 0)
> +               goto put;
> +
> +       /* Precalculate the match array - this simplifies match loop */
> +       for (i = 0; i < list_size; i++)
> +               initial_match_array[i] = cpu_to_be32(out_args->args[i]);
> +
> +       ret = -EINVAL;
> +       while (cur) {
> +               /* Get the <list>-map property */
> +               map = of_get_property(cur, map_name, &map_len);
> +               if (!map) {
> +                       ret = 0;
> +                       goto free;
> +               }
> +               map_len /= sizeof(u32);
> +
> +               /* Get the <list>-map-mask property (optional) */
> +               mask = of_get_property(cur, mask_name, NULL);
> +               if (!mask)
> +                       mask = dummy_mask;
> +               /* Iterate through <list>-map property */
> +               match = 0;
> +               while (map_len > (list_size + 1) && !match) {
> +                       /* Compare specifiers */
> +                       match = 1;
> +                       for (i = 0; i < list_size; i++, map_len--)
> +                               match &= !((match_array[i] ^ *map++) & mask[i]);
> +
> +                       of_node_put(new);
> +                       new = of_find_node_by_phandle(be32_to_cpup(map));
> +                       map++;
> +                       map_len--;
> +
> +                       /* Check if not found */
> +                       if (!new)
> +                               goto put;
> +
> +                       if (!of_device_is_available(new))
> +                               match = 0;
> +

> +                       tmp = of_get_property(new, cells_name, NULL);
> +                       if (!tmp)
> +                               goto put;
> +
> +                       new_size = be32_to_cpu(*tmp);

This can use of_property_read_u32.

> +
> +                       /* Check for malformed properties */
> +                       if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
> +                               goto put;
> +                       if (map_len < new_size)
> +                               goto put;
> +
> +                       /* Move forward by new node's #<list>-cells amount */
> +                       map += new_size;
> +                       map_len -= new_size;
> +               }
> +               if (!match)
> +                       goto put;
> +
> +               /* Get the <list>-map-pass-thru property (optional) */
> +               pass = of_get_property(cur, pass_name, NULL);
> +               if (!pass)
> +                       pass = dummy_pass;
> +
> +               /*
> +                * Successfully parsed a <list>-map translation; copy new
> +                * specifier into the out_args structure, keeping the
> +                * bits specified in <list>-map-pass-thru.
> +                */
> +               match_array = map - new_size;
> +               for (i = 0; i < new_size; i++) {
> +                       __be32 val = *(map - new_size + i);
> +
> +                       if (i < list_size) {
> +                               val &= ~pass[i];
> +                               val |= cpu_to_be32(out_args->args[i]) & pass[i];
> +                       }
> +
> +                       out_args->args[i] = be32_to_cpu(val);
> +               }
> +               out_args->args_count = list_size = new_size;
> +               /* Iterate again with new provider */
> +               out_args->np = new;
> +               of_node_put(cur);
> +               cur = new;
> +       }
> +put:
> +       of_node_put(cur);
> +       of_node_put(new);
> +free:
> +       kfree(mask_name);
> +       kfree(map_name);
> +       kfree(cells_name);
> +       kfree(pass_name);
> +
> +       return ret;
> +}
> +EXPORT_SYMBOL(of_parse_phandle_with_args_map);
> +
> +/**
>   * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
>   * @np:                pointer to a device tree node containing a list
>   * @list_name: property name that contains a list

Re: [PATCH v2 1/3] of: Support parsing phandle argument lists through a nexus node

[Rob Herring]

On Tue, Jan 17, 2017 at 6:50 PM, Stephen Boyd <stephen.boyd@linaro.org> wrote:
> Platforms like 96boards have a standardized connector/expansion
> slot that exposes signals like GPIOs to expansion boards in an
> SoC agnostic way. We'd like the DT overlays for the expansion
> boards to be written once without knowledge of the SoC on the
> other side of the connector. This avoids the unscalable
> combinatorial explosion of a different DT overlay for each
> expansion board and SoC pair.
>
> We need a way to describe the GPIOs routed through the connector
> in an SoC agnostic way. Let's introduce nexus property parsing
> into the OF core to do this. This is largely based on the
> interrupt nexus support we already have. This allows us to remap
> a phandle list in a consumer node (e.g. reset-gpios) through a
> connector in a generic way (e.g. via gpio-map). Do this in a
> generic routine so that we can remap any sort of variable length
> phandle list.
>
> Taking GPIOs as an example, the connector would be a GPIO nexus,
> supporting the remapping of a GPIO specifier space to multiple
> GPIO providers on the SoC. DT would look as shown below, where
> 'soc_gpio1' and 'soc_gpio2' are inside the SoC, 'connector' is an
> expansion port where boards can be plugged in, and
> 'expansion_device' is a device on the expansion board.
>
>         soc {
>                 soc_gpio1: gpio-controller1 {
>                         #gpio-cells = <2>;
>                 };
>
>                 soc_gpio2: gpio-controller2 {
>                         #gpio-cells = <2>;
>                 };
>         };
>
>         connector: connector {
>                 #gpio-cells = <2>;
>                 gpio-map = <0 0 &soc_gpio1 1 0>,
>                            <1 0 &soc_gpio2 4 0>,
>                            <2 0 &soc_gpio1 3 0>,
>                            <3 0 &soc_gpio2 2 0>;
>                 gpio-map-mask = <0xf 0x0>;
>                 gpio-map-pass-thru = <0x0 0x1>
>         };
>
>         expansion_device {
>                 reset-gpios = <&connector 2 GPIO_ACTIVE_LOW>;
>         };

This all looks good to me. A few nits below.

>
> The GPIO core would use of_parse_phandle_with_args_map() instead
> of of_parse_phandle_with_args() and arrive at the same type of
> result, a phandle and argument list. The difference is that the
> phandle and arguments will be remapped through the nexus node to
> the underlying SoC GPIO controller node. In the example above,
> we would remap 'reset-gpios' from <&connector 2 GPIO_ACTIVE_LOW>
> to <&soc_gpio1 3 GPIO_ACTIVE_LOW>.
>
> Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Mark Brown <broonie@kernel.org>
> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
> ---
>  drivers/of/base.c  | 186 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/of.h |  12 ++++
>  2 files changed, 198 insertions(+)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index d4bea3c797d6..277a81ff0479 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -1775,6 +1775,192 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
>  EXPORT_SYMBOL(of_parse_phandle_with_args);
>
>  /**
> + * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
> + * @np:                pointer to a device tree node containing a list
> + * @list_name: property name that contains a list
> + * @stem_name: stem of property names that specify phandles' arguments count
> + * @index:     index of a phandle to parse out
> + * @out_args:  optional pointer to output arguments structure (will be filled)
> + *
> + * This function is useful to parse lists of phandles and their arguments.
> + * Returns 0 on success and fills out_args, on error returns appropriate errno
> + * value. The difference between this function and of_parse_phandle_with_args()
> + * is that this API remaps a phandle if the node the phandle points to has
> + * a <@stem_name>-map property.
> + *
> + * Caller is responsible to call of_node_put() on the returned out_args->np
> + * pointer.
> + *
> + * Example:
> + *
> + * phandle1: node1 {
> + *     #list-cells = <2>;
> + * }
> + *
> + * phandle2: node2 {
> + *     #list-cells = <1>;
> + * }
> + *
> + * phandle3: node3 {
> + *     #list-cells = <1>;
> + *     list-map = <0 &phandle2 3>,
> + *                <1 &phandle2 2>,
> + *                <2 &phandle1 5 1>;
> + *     list-map-mask = <0x3>;
> + * };
> + *
> + * node4 {
> + *     list = <&phandle1 1 2 &phandle3 0>;
> + * }
> + *
> + * To get a device_node of the `node2' node you may call this:
> + * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
> + */
> +int of_parse_phandle_with_args_map(const struct device_node *np,
> +                                  const char *list_name,
> +                                  const char *stem_name,
> +                                  int index, struct of_phandle_args *out_args)
> +{
> +       char *cells_name, *map_name = NULL, *mask_name = NULL;
> +       char *pass_name = NULL;
> +       struct device_node *cur, *new = NULL;
> +       const __be32 *map, *mask, *pass, *tmp;

> +       const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
> +       const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };

These could be static and save some stack space.

> +       __be32 initial_match_array[MAX_PHANDLE_ARGS];

We worked to get rid of this MAX_PHANDLE_ARGS limitation. I guess this
is fine as I don't think we'll do an IOMMU thru a connector which is
the main thing having long args list.

> +       const __be32 *match_array = initial_match_array;
> +       int i, ret, map_len, match;
> +       u32 list_size, new_size;
> +
> +       if (index < 0)
> +               return -EINVAL;
> +
> +       cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
> +       if (!cells_name)
> +               return -ENOMEM;
> +
> +       ret = -ENOMEM;
> +       map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
> +       if (!map_name)
> +               goto free;
> +
> +       mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
> +       if (!mask_name)
> +               goto free;
> +
> +       pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
> +       if (!pass_name)
> +               goto free;
> +
> +       ret = __of_parse_phandle_with_args(np, list_name, cells_name, 0, index,
> +                                          out_args);
> +       if (ret)
> +               goto free;
> +
> +       /* Get the #<list>-cells property */
> +       cur = out_args->np;
> +       ret = of_property_read_u32(cur, cells_name, &list_size);
> +       if (ret < 0)
> +               goto put;
> +
> +       /* Precalculate the match array - this simplifies match loop */
> +       for (i = 0; i < list_size; i++)
> +               initial_match_array[i] = cpu_to_be32(out_args->args[i]);
> +
> +       ret = -EINVAL;
> +       while (cur) {
> +               /* Get the <list>-map property */
> +               map = of_get_property(cur, map_name, &map_len);
> +               if (!map) {
> +                       ret = 0;
> +                       goto free;
> +               }
> +               map_len /= sizeof(u32);
> +
> +               /* Get the <list>-map-mask property (optional) */
> +               mask = of_get_property(cur, mask_name, NULL);
> +               if (!mask)
> +                       mask = dummy_mask;
> +               /* Iterate through <list>-map property */
> +               match = 0;
> +               while (map_len > (list_size + 1) && !match) {
> +                       /* Compare specifiers */
> +                       match = 1;
> +                       for (i = 0; i < list_size; i++, map_len--)
> +                               match &= !((match_array[i] ^ *map++) & mask[i]);
> +
> +                       of_node_put(new);
> +                       new = of_find_node_by_phandle(be32_to_cpup(map));
> +                       map++;
> +                       map_len--;
> +
> +                       /* Check if not found */
> +                       if (!new)
> +                               goto put;
> +
> +                       if (!of_device_is_available(new))
> +                               match = 0;
> +

> +                       tmp = of_get_property(new, cells_name, NULL);
> +                       if (!tmp)
> +                               goto put;
> +
> +                       new_size = be32_to_cpu(*tmp);

This can use of_property_read_u32.

> +
> +                       /* Check for malformed properties */
> +                       if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
> +                               goto put;
> +                       if (map_len < new_size)
> +                               goto put;
> +
> +                       /* Move forward by new node's #<list>-cells amount */
> +                       map += new_size;
> +                       map_len -= new_size;
> +               }
> +               if (!match)
> +                       goto put;
> +
> +               /* Get the <list>-map-pass-thru property (optional) */
> +               pass = of_get_property(cur, pass_name, NULL);
> +               if (!pass)
> +                       pass = dummy_pass;
> +
> +               /*
> +                * Successfully parsed a <list>-map translation; copy new
> +                * specifier into the out_args structure, keeping the
> +                * bits specified in <list>-map-pass-thru.
> +                */
> +               match_array = map - new_size;
> +               for (i = 0; i < new_size; i++) {
> +                       __be32 val = *(map - new_size + i);
> +
> +                       if (i < list_size) {
> +                               val &= ~pass[i];
> +                               val |= cpu_to_be32(out_args->args[i]) & pass[i];
> +                       }
> +
> +                       out_args->args[i] = be32_to_cpu(val);
> +               }
> +               out_args->args_count = list_size = new_size;
> +               /* Iterate again with new provider */
> +               out_args->np = new;
> +               of_node_put(cur);
> +               cur = new;
> +       }
> +put:
> +       of_node_put(cur);
> +       of_node_put(new);
> +free:
> +       kfree(mask_name);
> +       kfree(map_name);
> +       kfree(cells_name);
> +       kfree(pass_name);
> +
> +       return ret;
> +}
> +EXPORT_SYMBOL(of_parse_phandle_with_args_map);
> +
> +/**
>   * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
>   * @np:                pointer to a device tree node containing a list
>   * @list_name: property name that contains a list

[PATCH v2 1/3] of: Support parsing phandle argument lists through a nexus node

[Rob Herring]

On Tue, Jan 17, 2017 at 6:50 PM, Stephen Boyd <stephen.boyd@linaro.org> wrote:
> Platforms like 96boards have a standardized connector/expansion
> slot that exposes signals like GPIOs to expansion boards in an
> SoC agnostic way. We'd like the DT overlays for the expansion
> boards to be written once without knowledge of the SoC on the
> other side of the connector. This avoids the unscalable
> combinatorial explosion of a different DT overlay for each
> expansion board and SoC pair.
>
> We need a way to describe the GPIOs routed through the connector
> in an SoC agnostic way. Let's introduce nexus property parsing
> into the OF core to do this. This is largely based on the
> interrupt nexus support we already have. This allows us to remap
> a phandle list in a consumer node (e.g. reset-gpios) through a
> connector in a generic way (e.g. via gpio-map). Do this in a
> generic routine so that we can remap any sort of variable length
> phandle list.
>
> Taking GPIOs as an example, the connector would be a GPIO nexus,
> supporting the remapping of a GPIO specifier space to multiple
> GPIO providers on the SoC. DT would look as shown below, where
> 'soc_gpio1' and 'soc_gpio2' are inside the SoC, 'connector' is an
> expansion port where boards can be plugged in, and
> 'expansion_device' is a device on the expansion board.
>
>         soc {
>                 soc_gpio1: gpio-controller1 {
>                         #gpio-cells = <2>;
>                 };
>
>                 soc_gpio2: gpio-controller2 {
>                         #gpio-cells = <2>;
>                 };
>         };
>
>         connector: connector {
>                 #gpio-cells = <2>;
>                 gpio-map = <0 0 &soc_gpio1 1 0>,
>                            <1 0 &soc_gpio2 4 0>,
>                            <2 0 &soc_gpio1 3 0>,
>                            <3 0 &soc_gpio2 2 0>;
>                 gpio-map-mask = <0xf 0x0>;
>                 gpio-map-pass-thru = <0x0 0x1>
>         };
>
>         expansion_device {
>                 reset-gpios = <&connector 2 GPIO_ACTIVE_LOW>;
>         };

This all looks good to me. A few nits below.

>
> The GPIO core would use of_parse_phandle_with_args_map() instead
> of of_parse_phandle_with_args() and arrive at the same type of
> result, a phandle and argument list. The difference is that the
> phandle and arguments will be remapped through the nexus node to
> the underlying SoC GPIO controller node. In the example above,
> we would remap 'reset-gpios' from <&connector 2 GPIO_ACTIVE_LOW>
> to <&soc_gpio1 3 GPIO_ACTIVE_LOW>.
>
> Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Mark Brown <broonie@kernel.org>
> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
> ---
>  drivers/of/base.c  | 186 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/of.h |  12 ++++
>  2 files changed, 198 insertions(+)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index d4bea3c797d6..277a81ff0479 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -1775,6 +1775,192 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
>  EXPORT_SYMBOL(of_parse_phandle_with_args);
>
>  /**
> + * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
> + * @np:                pointer to a device tree node containing a list
> + * @list_name: property name that contains a list
> + * @stem_name: stem of property names that specify phandles' arguments count
> + * @index:     index of a phandle to parse out
> + * @out_args:  optional pointer to output arguments structure (will be filled)
> + *
> + * This function is useful to parse lists of phandles and their arguments.
> + * Returns 0 on success and fills out_args, on error returns appropriate errno
> + * value. The difference between this function and of_parse_phandle_with_args()
> + * is that this API remaps a phandle if the node the phandle points to has
> + * a <@stem_name>-map property.
> + *
> + * Caller is responsible to call of_node_put() on the returned out_args->np
> + * pointer.
> + *
> + * Example:
> + *
> + * phandle1: node1 {
> + *     #list-cells = <2>;
> + * }
> + *
> + * phandle2: node2 {
> + *     #list-cells = <1>;
> + * }
> + *
> + * phandle3: node3 {
> + *     #list-cells = <1>;
> + *     list-map = <0 &phandle2 3>,
> + *                <1 &phandle2 2>,
> + *                <2 &phandle1 5 1>;
> + *     list-map-mask = <0x3>;
> + * };
> + *
> + * node4 {
> + *     list = <&phandle1 1 2 &phandle3 0>;
> + * }
> + *
> + * To get a device_node of the `node2' node you may call this:
> + * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
> + */
> +int of_parse_phandle_with_args_map(const struct device_node *np,
> +                                  const char *list_name,
> +                                  const char *stem_name,
> +                                  int index, struct of_phandle_args *out_args)
> +{
> +       char *cells_name, *map_name = NULL, *mask_name = NULL;
> +       char *pass_name = NULL;
> +       struct device_node *cur, *new = NULL;
> +       const __be32 *map, *mask, *pass, *tmp;

> +       const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
> +       const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };

These could be static and save some stack space.

> +       __be32 initial_match_array[MAX_PHANDLE_ARGS];

We worked to get rid of this MAX_PHANDLE_ARGS limitation. I guess this
is fine as I don't think we'll do an IOMMU thru a connector which is
the main thing having long args list.

> +       const __be32 *match_array = initial_match_array;
> +       int i, ret, map_len, match;
> +       u32 list_size, new_size;
> +
> +       if (index < 0)
> +               return -EINVAL;
> +
> +       cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
> +       if (!cells_name)
> +               return -ENOMEM;
> +
> +       ret = -ENOMEM;
> +       map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
> +       if (!map_name)
> +               goto free;
> +
> +       mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
> +       if (!mask_name)
> +               goto free;
> +
> +       pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
> +       if (!pass_name)
> +               goto free;
> +
> +       ret = __of_parse_phandle_with_args(np, list_name, cells_name, 0, index,
> +                                          out_args);
> +       if (ret)
> +               goto free;
> +
> +       /* Get the #<list>-cells property */
> +       cur = out_args->np;
> +       ret = of_property_read_u32(cur, cells_name, &list_size);
> +       if (ret < 0)
> +               goto put;
> +
> +       /* Precalculate the match array - this simplifies match loop */
> +       for (i = 0; i < list_size; i++)
> +               initial_match_array[i] = cpu_to_be32(out_args->args[i]);
> +
> +       ret = -EINVAL;
> +       while (cur) {
> +               /* Get the <list>-map property */
> +               map = of_get_property(cur, map_name, &map_len);
> +               if (!map) {
> +                       ret = 0;
> +                       goto free;
> +               }
> +               map_len /= sizeof(u32);
> +
> +               /* Get the <list>-map-mask property (optional) */
> +               mask = of_get_property(cur, mask_name, NULL);
> +               if (!mask)
> +                       mask = dummy_mask;
> +               /* Iterate through <list>-map property */
> +               match = 0;
> +               while (map_len > (list_size + 1) && !match) {
> +                       /* Compare specifiers */
> +                       match = 1;
> +                       for (i = 0; i < list_size; i++, map_len--)
> +                               match &= !((match_array[i] ^ *map++) & mask[i]);
> +
> +                       of_node_put(new);
> +                       new = of_find_node_by_phandle(be32_to_cpup(map));
> +                       map++;
> +                       map_len--;
> +
> +                       /* Check if not found */
> +                       if (!new)
> +                               goto put;
> +
> +                       if (!of_device_is_available(new))
> +                               match = 0;
> +

> +                       tmp = of_get_property(new, cells_name, NULL);
> +                       if (!tmp)
> +                               goto put;
> +
> +                       new_size = be32_to_cpu(*tmp);

This can use of_property_read_u32.

> +
> +                       /* Check for malformed properties */
> +                       if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
> +                               goto put;
> +                       if (map_len < new_size)
> +                               goto put;
> +
> +                       /* Move forward by new node's #<list>-cells amount */
> +                       map += new_size;
> +                       map_len -= new_size;
> +               }
> +               if (!match)
> +                       goto put;
> +
> +               /* Get the <list>-map-pass-thru property (optional) */
> +               pass = of_get_property(cur, pass_name, NULL);
> +               if (!pass)
> +                       pass = dummy_pass;
> +
> +               /*
> +                * Successfully parsed a <list>-map translation; copy new
> +                * specifier into the out_args structure, keeping the
> +                * bits specified in <list>-map-pass-thru.
> +                */
> +               match_array = map - new_size;
> +               for (i = 0; i < new_size; i++) {
> +                       __be32 val = *(map - new_size + i);
> +
> +                       if (i < list_size) {
> +                               val &= ~pass[i];
> +                               val |= cpu_to_be32(out_args->args[i]) & pass[i];
> +                       }
> +
> +                       out_args->args[i] = be32_to_cpu(val);
> +               }
> +               out_args->args_count = list_size = new_size;
> +               /* Iterate again with new provider */
> +               out_args->np = new;
> +               of_node_put(cur);
> +               cur = new;
> +       }
> +put:
> +       of_node_put(cur);
> +       of_node_put(new);
> +free:
> +       kfree(mask_name);
> +       kfree(map_name);
> +       kfree(cells_name);
> +       kfree(pass_name);
> +
> +       return ret;
> +}
> +EXPORT_SYMBOL(of_parse_phandle_with_args_map);
> +
> +/**
>   * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
>   * @np:                pointer to a device tree node containing a list
>   * @list_name: property name that contains a list