diff mbox series

[v2,01/13] of: property: add port base loop

Message ID 87ede1klgr.wl-kuninori.morimoto.gx@renesas.com
State New
Headers show
Series [v2,01/13] of: property: add port base loop | expand

Commit Message

Kuninori Morimoto Jan. 29, 2024, 12:54 a.m. UTC 
We have endpoint base functions
	- of_graph_get_next_endpoint()
	- of_graph_get_endpoint_count()
	- for_each_endpoint_of_node()

Here, for_each_endpoint_of_node() loop finds each endpoints

	ports {
		port@0 {
(1)			endpoint {...};
		};
		port@1 {
(2)			endpoint {...};
		};
		...
	};

In above case, for_each_endpoint_of_node() loop finds endpoint as
(1) -> (2) -> ...

Basically, user/driver knows which port is used for what, but not in
all cases. For example on flexible/generic driver case, how many ports
are used is not fixed.

For example Sound Generic Card driver which is used from many venders
can't know how many ports are used. Because the driver is very
flexible/generic, it is impossible to know how many ports are used,
it depends on each vender SoC and/or its used board.

And more, the port can have multi endpoints. For example Generic Sound
Card case, it supports many type of connection between CPU / Codec, and
some of them uses multi endpoint in one port.
Then, Generic Sound Card want to handle each connection via "port"
instead of "endpoint".
But, it is very difficult to handle each "port" by
for_each_endpoint_of_node(). Getting "port" by using of_get_parent()
from "endpoint" doesn't work. see below.

	ports {
		port@0 {
(1)			endpoint@0 {...};
(2)			endpoint@1 {...};
		};
		port@1 {
(3)			endpoint {...};
		};
		...
	};

Add "port" base functions.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
 drivers/of/property.c    | 48 ++++++++++++++++++++++++++++++++++++++++
 include/linux/of_graph.h | 21 ++++++++++++++++++
 2 files changed, 69 insertions(+)

Comments

Rob Herring (Arm) Jan. 31, 2024, 6:52 p.m. UTC | #1 
On Mon, Jan 29, 2024 at 12:54:44AM +0000, Kuninori Morimoto wrote:
> We have endpoint base functions
> 	- of_graph_get_next_endpoint()
> 	- of_graph_get_endpoint_count()
> 	- for_each_endpoint_of_node()
> 
> Here, for_each_endpoint_of_node() loop finds each endpoints
> 
> 	ports {
> 		port@0 {
> (1)			endpoint {...};
> 		};
> 		port@1 {
> (2)			endpoint {...};
> 		};
> 		...
> 	};
> 
> In above case, for_each_endpoint_of_node() loop finds endpoint as
> (1) -> (2) -> ...
> 
> Basically, user/driver knows which port is used for what, but not in
> all cases. For example on flexible/generic driver case, how many ports
> are used is not fixed.
> 
> For example Sound Generic Card driver which is used from many venders
> can't know how many ports are used. Because the driver is very
> flexible/generic, it is impossible to know how many ports are used,
> it depends on each vender SoC and/or its used board.
> 
> And more, the port can have multi endpoints. For example Generic Sound
> Card case, it supports many type of connection between CPU / Codec, and
> some of them uses multi endpoint in one port.
> Then, Generic Sound Card want to handle each connection via "port"
> instead of "endpoint".
> But, it is very difficult to handle each "port" by
> for_each_endpoint_of_node(). Getting "port" by using of_get_parent()
> from "endpoint" doesn't work. see below.
> 
> 	ports {
> 		port@0 {
> (1)			endpoint@0 {...};
> (2)			endpoint@1 {...};
> 		};
> 		port@1 {
> (3)			endpoint {...};
> 		};
> 		...
> 	};
> 
> Add "port" base functions.
> 
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> ---
>  drivers/of/property.c    | 48 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/of_graph.h | 21 ++++++++++++++++++
>  2 files changed, 69 insertions(+)
> 
> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index afdaefbd03f6..9e670e99dbbb 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -631,6 +631,42 @@ struct device_node *of_graph_get_port_by_id(struct device_node *parent, u32 id)
>  }
>  EXPORT_SYMBOL(of_graph_get_port_by_id);
>  
> +/**
> + * of_graph_get_next_port() - get next port node
> + * @parent: pointer to the parent device node
> + * @port: current port node, or NULL to get first
> + *
> + * Return: An 'port' node pointer with refcount incremented. Refcount
> + * of the passed @prev node is decremented.
> + */
> +struct device_node *of_graph_get_next_port(const struct device_node *parent,
> +					   struct device_node *port)
> +{
> +	if (!parent)
> +		return NULL;
> +
> +	if (!port) {
> +		struct device_node *node;
> +
> +		node = of_get_child_by_name(parent, "ports");
> +		if (node) {
> +			parent = node;
> +			of_node_put(node);

The original code had this right, but here you have it wrong.

You are releasing ports here, but then using it...

> +		}
> +
> +		return of_get_child_by_name(parent, "port");

...here. You have to get the child before you can put the parent.

> +	}
> +
> +	do {
> +		port = of_get_next_child(parent, port);
> +		if (!port)
> +			break;
> +	} while (!of_node_name_eq(port, "port"));
> +
> +	return port;
> +}
> +EXPORT_SYMBOL(of_graph_get_next_port);
> +
Kuninori Morimoto Jan. 31, 2024, 11:25 p.m. UTC | #2 
Hi Rob

Thank you for review

> > +/**
> > + * of_graph_get_next_port() - get next port node
> > + * @parent: pointer to the parent device node
> > + * @port: current port node, or NULL to get first
> > + *
> > + * Return: An 'port' node pointer with refcount incremented. Refcount
> > + * of the passed @prev node is decremented.
> > + */
> > +struct device_node *of_graph_get_next_port(const struct device_node *parent,
> > +					   struct device_node *port)
> > +{
> > +	if (!parent)
> > +		return NULL;
> > +
> > +	if (!port) {
> > +		struct device_node *node;
> > +
> > +		node = of_get_child_by_name(parent, "ports");
> > +		if (node) {
> > +			parent = node;
> > +			of_node_put(node);
> 
> The original code had this right, but here you have it wrong.
> 
> You are releasing ports here, but then using it...
> 
> > +		}
> > +
> > +		return of_get_child_by_name(parent, "port");
> 
> ...here. You have to get the child before you can put the parent.

You are reviewing v2, and it was already fixed in v3

Thank you for your help !!

Best regards
---
Renesas Electronics
Ph.D. Kuninori Morimoto
diff mbox series

Patch

diff --git a/drivers/of/property.c b/drivers/of/property.c
index afdaefbd03f6..9e670e99dbbb 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -631,6 +631,42 @@  struct device_node *of_graph_get_port_by_id(struct device_node *parent, u32 id)
 }
 EXPORT_SYMBOL(of_graph_get_port_by_id);
 
+/**
+ * of_graph_get_next_port() - get next port node
+ * @parent: pointer to the parent device node
+ * @port: current port node, or NULL to get first
+ *
+ * Return: An 'port' node pointer with refcount incremented. Refcount
+ * of the passed @prev node is decremented.
+ */
+struct device_node *of_graph_get_next_port(const struct device_node *parent,
+					   struct device_node *port)
+{
+	if (!parent)
+		return NULL;
+
+	if (!port) {
+		struct device_node *node;
+
+		node = of_get_child_by_name(parent, "ports");
+		if (node) {
+			parent = node;
+			of_node_put(node);
+		}
+
+		return of_get_child_by_name(parent, "port");
+	}
+
+	do {
+		port = of_get_next_child(parent, port);
+		if (!port)
+			break;
+	} while (!of_node_name_eq(port, "port"));
+
+	return port;
+}
+EXPORT_SYMBOL(of_graph_get_next_port);
+
 /**
  * of_graph_get_next_endpoint() - get next endpoint node
  * @parent: pointer to the parent device node
@@ -823,6 +859,18 @@  int of_graph_get_endpoint_count(const struct device_node *np)
 }
 EXPORT_SYMBOL(of_graph_get_endpoint_count);
 
+int of_graph_get_port_count(const struct device_node *np)
+{
+	struct device_node *port;
+	int num = 0;
+
+	for_each_port_of_node(np, port)
+		num++;
+
+	return num;
+}
+EXPORT_SYMBOL(of_graph_get_port_count);
+
 /**
  * of_graph_get_remote_node() - get remote parent device_node for given port/endpoint
  * @node: pointer to parent device_node containing graph port/endpoint
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
index 4d7756087b6b..fff598640e93 100644
--- a/include/linux/of_graph.h
+++ b/include/linux/of_graph.h
@@ -37,14 +37,28 @@  struct of_endpoint {
 	for (child = of_graph_get_next_endpoint(parent, NULL); child != NULL; \
 	     child = of_graph_get_next_endpoint(parent, child))
 
+/**
+ * for_each_port_of_node - iterate over every port in a device node
+ * @parent: parent device node containing ports/port
+ * @child: loop variable pointing to the current port node
+ *
+ * When breaking out of the loop, of_node_put(child) has to be called manually.
+ */
+#define for_each_port_of_node(parent, child)			\
+	for (child = of_graph_get_next_port(parent, NULL); child != NULL; \
+	     child = of_graph_get_next_port(parent, child))
+
 #ifdef CONFIG_OF
 bool of_graph_is_present(const struct device_node *node);
 int of_graph_parse_endpoint(const struct device_node *node,
 				struct of_endpoint *endpoint);
 int of_graph_get_endpoint_count(const struct device_node *np);
+int of_graph_get_port_count(const struct device_node *np);
 struct device_node *of_graph_get_port_by_id(struct device_node *node, u32 id);
 struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 					struct device_node *previous);
+struct device_node *of_graph_get_next_port(const struct device_node *parent,
+					   struct device_node *previous);
 struct device_node *of_graph_get_endpoint_by_regs(
 		const struct device_node *parent, int port_reg, int reg);
 struct device_node *of_graph_get_remote_endpoint(
@@ -86,6 +100,13 @@  static inline struct device_node *of_graph_get_next_endpoint(
 	return NULL;
 }
 
+static inline struct device_node *of_graph_get_next_port(
+					const struct device_node *parent,
+					struct device_node *previous)
+{
+	return NULL;
+}
+
 static inline struct device_node *of_graph_get_endpoint_by_regs(
 		const struct device_node *parent, int port_reg, int reg)
 {