| Message ID | 87le1aw8lw.wl-kuninori.morimoto.gx@renesas.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | of: property: add of_graph_get_next_port/port_endpoint() | expand |
On 06/08/2024 07:58, Kuninori Morimoto wrote: > We have endpoint base functions > - of_graph_get_next_device_endpoint() > - of_graph_get_device_endpoint_count() > - for_each_of_graph_device_endpoint() > > Here, for_each_of_graph_device_endpoint() loop finds each endpoints > > ports { > port@0 { > (1) endpoint {...}; > }; > port@1 { > (2) endpoint {...}; > }; > ... > }; > > In above case, it 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" via > for_each_of_graph_device_endpoint(). 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 {...}; > }; > ... > }; > > In the same time, same reason, we want to handle "ports" same as "port". > > node { > => ports@0 { > port@0 { > endpoint@0 {...}; > endpoint@1 {...}; > ... > }; > port@1 { > endpoint@0 {...}; > endpoint@1 {...}; > ... > }; > ... > }; > => ports@1 { > ... > }; > }; > > Add "ports" / "port" base functions. > For above case, we can use > > for_each_of_graph_ports(node, ports) { > for_each_of_graph_port(ports, port) { > ... > } > } > > This loop works in case of "node" doesn't have "ports" also. > > Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> > --- > drivers/of/property.c | 86 ++++++++++++++++++++++++++++++++++++++++ > include/linux/of_graph.h | 47 ++++++++++++++++++++++ > 2 files changed, 133 insertions(+) > > diff --git a/drivers/of/property.c b/drivers/of/property.c > index 164d77cb9445..3b2d09c0376a 100644 > --- a/drivers/of/property.c > +++ b/drivers/of/property.c > @@ -625,8 +625,76 @@ 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_ports() - get next ports node. > + * @parent: pointer to the parent device node > + * @ports: current ports node, or NULL to get first > + * > + * Return: A 'ports' node pointer with refcount incremented. Refcount > + * of the passed @prev node is decremented. No "prev" argument in the code. The of_graph_get_next_endpoint() function uses "previous" as the argument name (well, the function declaration uses "previous", the implementation uses "prev"...), and I would use the same naming here. Also of_graph_get_next_endpoint() talks about "previous endpoint node", whereas here it's "current ports node". I'd use the same style here, so "previous ports node". The same comments for the of_graph_get_next_port(). > + */ > +struct device_node *of_graph_get_next_ports(struct device_node *parent, > + struct device_node *ports) > +{ > + if (!parent) > + return NULL; > + > + if (!ports) { > + ports = of_get_child_by_name(parent, "ports"); > + > + /* use parent as its ports of this device if it not exist */ I think this needs to be described in the kernel doc. I understand the need for this, but it's somewhat counter-intuitive that this returns the parent node if there are no ports nodes, so it must be highlighted in the documentation. I wonder if a bit more complexity here would be good... I think here we could: - If there are no 'ports' nodes in the parent, but there is a 'port' node in the parent, return the parent node - If there are no 'ports' nor 'port' nodes in the parent, return NULL > + if (!ports) { > + ports = parent; > + of_node_get(ports); > + } You could just do "ports = of_node_get(parent);" > + > + return ports; > + } > + > + do { > + ports = of_get_next_child(parent, ports); > + if (!ports) > + break; > + } while (!of_node_name_eq(ports, "ports")); > + > + return ports; > +} > +EXPORT_SYMBOL(of_graph_get_next_ports); > + > +/** > + * 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: A 'port' node pointer with refcount incremented. Refcount > + * of the passed @prev node is decremented. > + */ > +struct device_node *of_graph_get_next_port(struct device_node *parent, > + struct device_node *port) > +{ > + if (!parent) > + return NULL; > + > + if (!port) { > + struct device_node *ports __free(device_node) = > + of_graph_get_next_ports(parent, NULL); > + > + return of_get_child_by_name(ports, "port"); > + } > + > + do { > + port = of_get_next_child(parent, port); > + if (!port) > + break; > + } while (!of_node_name_eq(port, "port")); > + > + return port; > +} Hmm... So if I call this with of_graph_get_next_port(dev_node, NULL) (dev_node being the device node of the device), it'll give me the first port in the first ports node, or the first port in the dev_node if there are no ports nodes? And if I then continue iterating with of_graph_get_next_port(dev_node, prev_port)... The call will return NULL if the dev_node contains "ports" node (because the dev_node does not contain any "port" nodes)? So if I understand right, of_graph_get_next_port() must always be called with a parent that contains port nodes. Sometimes that's the device's node (if there's just one port) and sometimes that's ports node. If it's called with a parent that contains ports node, it will not work correctly. If the above is right, then should this just return "of_get_child_by_name(parent, "port")" if !port, instead of calling of_graph_get_next_ports()? Or maybe I'm just getting confused here. But in any case, I think it would be very good to describe the behavior on the kernel doc for the different ports/port structure cases (also for of_graph_get_next_ports()), and be clear on what the parameters can be, i.e. what kind of device nodes can be given as parent, and how the function iterates over the ports. > +EXPORT_SYMBOL(of_graph_get_next_port); > + > /** > * of_graph_get_next_endpoint() - get next endpoint node > + * Extra change. > * @parent: pointer to the parent device node > * @prev: previous endpoint node, or NULL to get first > * > @@ -823,6 +891,24 @@ unsigned int of_graph_get_endpoint_count(const struct device_node *np) > } > EXPORT_SYMBOL(of_graph_get_endpoint_count); > > +/** > + * of_graph_get_port_count() - get count of port Perhaps "get the number of port nodes". > + * @np: pointer to the parent device node > + * > + * Return: count of port of this device node > + */ > +unsigned int of_graph_get_port_count(struct device_node *np) > +{ > + struct device_node *port = NULL; > + int num = 0; > + > + for_each_of_graph_port(np, port) > + num++; > + > + return num; > +} I my analysis above is right, calling of_graph_get_port_count(dev_node) will return 1, if the dev_node contains "ports" node which contains one or more "port" nodes. > +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 a4bea62bfa29..30169b50b042 100644 > --- a/include/linux/of_graph.h > +++ b/include/linux/of_graph.h > @@ -37,14 +37,42 @@ struct of_endpoint { > for (child = of_graph_get_next_endpoint(parent, NULL); child != NULL; \ > child = of_graph_get_next_endpoint(parent, child)) > > +/** > + * for_each_of_graph_ports - iterate over every ports in a device node > + * @parent: parent device node containing ports > + * @child: loop variable pointing to the current ports node > + * > + * When breaking out of the loop, of_node_put(child) has to be called manually. > + */ > +#define for_each_of_graph_ports(parent, child) \ > + for (child = of_graph_get_next_ports(parent, NULL); child != NULL; \ > + child = of_graph_get_next_ports(parent, child)) > + > +/** > + * for_each_of_graph_port - iterate over every port in a device or ports node > + * @parent: parent device or ports node containing 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_of_graph_port(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); > + Extra change. > unsigned int of_graph_get_endpoint_count(const struct device_node *np); > +unsigned int of_graph_get_port_count(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_ports(struct device_node *parent, > + struct device_node *ports); > +struct device_node *of_graph_get_next_port(struct device_node *parent, > + struct device_node *port); > 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( > @@ -73,6 +101,11 @@ static inline unsigned int of_graph_get_endpoint_count(const struct device_node > return 0; > } > > +static inline unsigned int of_graph_get_port_count(struct device_node *np) > +{ > + return 0; > +} > + > static inline struct device_node *of_graph_get_port_by_id( > struct device_node *node, u32 id) > { > @@ -86,6 +119,20 @@ static inline struct device_node *of_graph_get_next_endpoint( > return NULL; > } > > +static inline struct device_node *of_graph_get_next_ports( > + struct device_node *parent, > + struct device_node *previous) > +{ > + return NULL; > +} > + > +static inline struct device_node *of_graph_get_next_port( > + 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) > { Tomi
Hi Tomi Thank you for your review > > +/** > > + * of_graph_get_next_ports() - get next ports node. > > + * @parent: pointer to the parent device node > > + * @ports: current ports node, or NULL to get first > > + * > > + * Return: A 'ports' node pointer with refcount incremented. Refcount > > + * of the passed @prev node is decremented. > > No "prev" argument in the code. > > The of_graph_get_next_endpoint() function uses "previous" as the > argument name (well, the function declaration uses "previous", the > implementation uses "prev"...), and I would use the same naming here. > > Also of_graph_get_next_endpoint() talks about "previous endpoint node", > whereas here it's "current ports node". I'd use the same style here, so > "previous ports node". > > The same comments for the of_graph_get_next_port(). OK, thanks. Will fix in v2 > > +struct device_node *of_graph_get_next_ports(struct device_node *parent, > > + struct device_node *ports) > > +{ > > + if (!parent) > > + return NULL; > > + > > + if (!ports) { > > + ports = of_get_child_by_name(parent, "ports"); > > + > > + /* use parent as its ports of this device if it not exist */ > > I think this needs to be described in the kernel doc. I understand the > need for this, but it's somewhat counter-intuitive that this returns the > parent node if there are no ports nodes, so it must be highlighted in > the documentation. > > I wonder if a bit more complexity here would be good... I think here we > could: > > - If there are no 'ports' nodes in the parent, but there is a 'port' > node in the parent, return the parent node > - If there are no 'ports' nor 'port' nodes in the parent, return NULL Thanks, but unfortunately, get_next_ports() checks only "ports" and doesn't check whether it has "port" node or not. So correct comment here is maybe... If "parent" doesn't have "ports", it returns "parent" itself as "ports" I will add it on v2 > > +/** > > + * 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: A 'port' node pointer with refcount incremented. Refcount > > + * of the passed @prev node is decremented. > > + */ > > +struct device_node *of_graph_get_next_port(struct device_node *parent, > > + struct device_node *port) > > +{ > > + if (!parent) > > + return NULL; > > + > > + if (!port) { > > + struct device_node *ports __free(device_node) = > > + of_graph_get_next_ports(parent, NULL); > > + > > + return of_get_child_by_name(ports, "port"); > > + } > > + > > + do { > > + port = of_get_next_child(parent, port); > > + if (!port) > > + break; > > + } while (!of_node_name_eq(port, "port")); > > + > > + return port; > > +} > > Hmm... So if I call this with of_graph_get_next_port(dev_node, NULL) > (dev_node being the device node of the device), it'll give me the first > port in the first ports node, or the first port in the dev_node if there > are no ports nodes? Yes > And if I then continue iterating with of_graph_get_next_port(dev_node, > prev_port)... The call will return NULL if the dev_node contains "ports" > node (because the dev_node does not contain any "port" nodes)? > > So if I understand right, of_graph_get_next_port() must always be called > with a parent that contains port nodes. Sometimes that's the device's > node (if there's just one port) and sometimes that's ports node. If it's > called with a parent that contains ports node, it will not work correctly. > > If the above is right, then should this just return > "of_get_child_by_name(parent, "port")" if !port, instead of calling > of_graph_get_next_ports()? Hmm ? Do you mean you want access to ports@1 memeber port after ports@0 ? I have tested below in my test environment parent { (X) ports@0 { (A) port@0 { }; (B) port@1 { }; }; (Y) ports@1 { (C) port@0 { }; }; }; In this case, if you call get_next_port() with parent, you can get ports@0 member port. /* use "paramet" and use "ports@0" are same result */ // use parent port = of_graph_get_next_port(parent, NULL); // (A) port = of_graph_get_next_port(parent, port); // (B) port = of_graph_get_next_port(parent, port); // NULl // use ports@0 ports = of_graph_get_next_ports(parent, NULL); // (X) port = of_graph_get_next_port(ports, NULL); // (A) port = of_graph_get_next_port(ports, port); // (B) port = of_graph_get_next_port(ports, port); // NULl If you want to get ports@1 member port, you need to use ports@1. // use ports@1 ports = of_graph_get_next_ports(parent, NULL); // (X) ports = of_graph_get_next_ports(parent, ports); // (Y) port = of_graph_get_next_port(ports, NULL); // (C) I have confirmed in my test environment. But please double check it. Is this clear for you ? > Or maybe I'm just getting confused here. But in any case, I think it > would be very good to describe the behavior on the kernel doc for the > different ports/port structure cases (also for > of_graph_get_next_ports()), and be clear on what the parameters can be, > i.e. what kind of device nodes can be given as parent, and how the > function iterates over the ports. OK, will do in v2 > > + * @np: pointer to the parent device node > > + * > > + * Return: count of port of this device node > > + */ > > +unsigned int of_graph_get_port_count(struct device_node *np) > > +{ > > + struct device_node *port = NULL; > > + int num = 0; > > + > > + for_each_of_graph_port(np, port) > > + num++; > > + > > + return num; > > +} > > I my analysis above is right, calling of_graph_get_port_count(dev_node) > will return 1, if the dev_node contains "ports" node which contains one > or more "port" nodes. In my test, it will be.. parent { ports@0 { port@0 { }; port@1 { }; }; ports@1 { port@0 { }; }; }; of_graph_get_port_count(parent); // 2 = number of ports@0 of_graph_get_port_count(ports0); // 2 = number of ports@0 of_graph_get_port_count(ports1); // 1 = number of ports@1 Thank you for your help !! Best regards --- Kuninori Morimoto
Hi, On 09/08/2024 05:10, Kuninori Morimoto wrote: > > Hi Tomi > > Thank you for your review > > >>> +/** >>> + * of_graph_get_next_ports() - get next ports node. >>> + * @parent: pointer to the parent device node >>> + * @ports: current ports node, or NULL to get first >>> + * >>> + * Return: A 'ports' node pointer with refcount incremented. Refcount >>> + * of the passed @prev node is decremented. >> >> No "prev" argument in the code. >> >> The of_graph_get_next_endpoint() function uses "previous" as the >> argument name (well, the function declaration uses "previous", the >> implementation uses "prev"...), and I would use the same naming here. >> >> Also of_graph_get_next_endpoint() talks about "previous endpoint node", >> whereas here it's "current ports node". I'd use the same style here, so >> "previous ports node". >> >> The same comments for the of_graph_get_next_port(). > > OK, thanks. Will fix in v2 > >>> +struct device_node *of_graph_get_next_ports(struct device_node *parent, >>> + struct device_node *ports) >>> +{ >>> + if (!parent) >>> + return NULL; >>> + >>> + if (!ports) { >>> + ports = of_get_child_by_name(parent, "ports"); >>> + >>> + /* use parent as its ports of this device if it not exist */ >> >> I think this needs to be described in the kernel doc. I understand the >> need for this, but it's somewhat counter-intuitive that this returns the >> parent node if there are no ports nodes, so it must be highlighted in >> the documentation. >> >> I wonder if a bit more complexity here would be good... I think here we >> could: >> >> - If there are no 'ports' nodes in the parent, but there is a 'port' >> node in the parent, return the parent node >> - If there are no 'ports' nor 'port' nodes in the parent, return NULL > > Thanks, but unfortunately, get_next_ports() checks only "ports" and > doesn't check whether it has "port" node or not. Yes, my point was if the check should be added. My reasoning is: If we have this, of_graph_get_next_ports() returns the ports@0, and that makes sense: parent { ports@0 { port@0 { }; }; }; If we have this, of_graph_get_next_ports() returns the parent, and that's a bit surprising, but I can see the need, and it just needs to be documented: parent { port { }; }; But if we have this, does it make sense that of_graph_get_next_ports() returns the parent, or should it return NULL: parent { /* No ports or port */ }; > So correct comment here is maybe... > > If "parent" doesn't have "ports", it returns "parent" itself as "ports" > > I will add it on v2 > >>> +/** >>> + * 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: A 'port' node pointer with refcount incremented. Refcount >>> + * of the passed @prev node is decremented. >>> + */ >>> +struct device_node *of_graph_get_next_port(struct device_node *parent, >>> + struct device_node *port) >>> +{ >>> + if (!parent) >>> + return NULL; >>> + >>> + if (!port) { >>> + struct device_node *ports __free(device_node) = >>> + of_graph_get_next_ports(parent, NULL); >>> + >>> + return of_get_child_by_name(ports, "port"); >>> + } >>> + >>> + do { >>> + port = of_get_next_child(parent, port); >>> + if (!port) >>> + break; >>> + } while (!of_node_name_eq(port, "port")); >>> + >>> + return port; >>> +} >> >> Hmm... So if I call this with of_graph_get_next_port(dev_node, NULL) >> (dev_node being the device node of the device), it'll give me the first >> port in the first ports node, or the first port in the dev_node if there >> are no ports nodes? > > Yes > >> And if I then continue iterating with of_graph_get_next_port(dev_node, >> prev_port)... The call will return NULL if the dev_node contains "ports" >> node (because the dev_node does not contain any "port" nodes)? >> >> So if I understand right, of_graph_get_next_port() must always be called >> with a parent that contains port nodes. Sometimes that's the device's >> node (if there's just one port) and sometimes that's ports node. If it's >> called with a parent that contains ports node, it will not work correctly. >> >> If the above is right, then should this just return >> "of_get_child_by_name(parent, "port")" if !port, instead of calling >> of_graph_get_next_ports()? > > Hmm ? Do you mean you want access to ports@1 memeber port after ports@0 ? > I have tested below in my test environment > > parent { > (X) ports@0 { > (A) port@0 { }; > (B) port@1 { }; > }; > (Y) ports@1 { > (C) port@0 { }; > }; > }; > > In this case, if you call get_next_port() with parent, > you can get ports@0 member port. > > /* use "paramet" and use "ports@0" are same result */ > > // use parent > port = of_graph_get_next_port(parent, NULL); // (A) > port = of_graph_get_next_port(parent, port); // (B) > port = of_graph_get_next_port(parent, port); // NULl > > // use ports@0 > ports = of_graph_get_next_ports(parent, NULL); // (X) > port = of_graph_get_next_port(ports, NULL); // (A) > port = of_graph_get_next_port(ports, port); // (B) > port = of_graph_get_next_port(ports, port); // NULl > > If you want to get ports@1 member port, you need to use ports@1. > > // use ports@1 > ports = of_graph_get_next_ports(parent, NULL); // (X) > ports = of_graph_get_next_ports(parent, ports); // (Y) > port = of_graph_get_next_port(ports, NULL); // (C) > > I have confirmed in my test environment. > But please double check it. Is this clear for you ? Ah, I see now. I was expecting of_get_next_child() to return children of 'parent', but that's actually not the case. So when you call: port = of_graph_get_next_port(parent, NULL); // (A) the function will call 'ports = of_graph_get_next_ports(parent, NULL)' (ports is (X)) and then return of_get_child_by_name(ports, "port") (which is (A)). This is fine. port = of_graph_get_next_port(parent, port); // (B) Here the function will call 'port = of_get_next_child(parent, port)', where parent is the parent node, and port is (A). The problem is, (A) is not a child of the parent. This seems to work, as of_get_next_child() does not use the 'parent' for anything if 'port' is given, instead if just gives the next sibling of 'port'. port = of_graph_get_next_port(parent, port); // NULl And now when the function calls of_get_next_child(parent, port), it does not give the next child of parent, but instead NULL because 'port' has no more siblings. The documentation for of_get_next_child() doesn't mention if calling of_get_next_child(parent, child) is valid when the given child is actually not a child of the parent. The doc says that 'prev' parameter should be "previous child of the parent node", which is not the case here. So using it like this does not sound right to me. And just looking at the behavior of: > port = of_graph_get_next_port(parent, NULL); // (A) > port = of_graph_get_next_port(parent, port); // (B) > port = of_graph_get_next_port(parent, port); // NULl it does not feel right. Why does of_graph_get_next_port() return only the ports of ports@0? I think it should either return nothing, as there are no 'port' nodes in the parent, or it should return all the port nodes from all the ports nodes. Can we just drop the use of of_graph_get_next_ports() from of_graph_get_next_port()? In other words, make of_graph_get_next_port() iterate the 'port' nodes strictly only in the given parent node. I think we have the same problem in of_graph_get_next_ports(). If we have: parent { port { }; }; And we do: ports = of_graph_get_next_ports(parent, NULL) The returned 'ports' is actually the 'parent'. If we then call: ports = of_graph_get_next_ports(parent, ports) we are effectively calling of_graph_get_next_ports(parent, parent). This results in of_get_next_child(parent, parent). of_get_next_child() will return the next sibling of parent (so, perhaps, a node for some unrelated device). It then checks if the name of that node is 'ports'. So, while unlikely, if we have: bus { /* our display device */ display { port { }; }; /* some odd ports device */ ports { }; }; and you use of_graph_get_next_ports() for display, you'll end up getting the 'ports' node. I have to say, I feel that making the 'ports' node optional in the graph DT bindings was a mistake, but nothing we can do about that... Can you try adding "WARN_ON(node && prev && node != prev->parent)" to of_get_next_child()? >> Or maybe I'm just getting confused here. But in any case, I think it >> would be very good to describe the behavior on the kernel doc for the >> different ports/port structure cases (also for >> of_graph_get_next_ports()), and be clear on what the parameters can be, >> i.e. what kind of device nodes can be given as parent, and how the >> function iterates over the ports. > > OK, will do in v2 > >>> + * @np: pointer to the parent device node >>> + * >>> + * Return: count of port of this device node >>> + */ >>> +unsigned int of_graph_get_port_count(struct device_node *np) >>> +{ >>> + struct device_node *port = NULL; >>> + int num = 0; >>> + >>> + for_each_of_graph_port(np, port) >>> + num++; >>> + >>> + return num; >>> +} >> >> I my analysis above is right, calling of_graph_get_port_count(dev_node) >> will return 1, if the dev_node contains "ports" node which contains one >> or more "port" nodes. > > In my test, it will be.. > > parent { > ports@0 { > port@0 { }; > port@1 { }; > }; > ports@1 { > port@0 { }; > }; > }; > > of_graph_get_port_count(parent); // 2 = number of ports@0 I think the above is a bit surprising, and in my opinion points that there is a problem. Why does using 'parent' equate to only using 'ports@0'? Again, I would expect either to get 0 (as there are no 'port' nodes in parent, or 3. > of_graph_get_port_count(ports0); // 2 = number of ports@0 > of_graph_get_port_count(ports1); // 1 = number of ports@1 > > > Thank you for your help !! > > Best regards > --- > Kuninori Morimoto Tomi
Hi Tomi Thank you for the feedback, and sorry for my late responce. I was under Summer Vacation > If we have this, of_graph_get_next_ports() returns the ports@0, and that > makes sense: > > parent { > ports@0 { > port@0 { }; > }; > }; > > If we have this, of_graph_get_next_ports() returns the parent, and > that's a bit surprising, but I can see the need, and it just needs to be > documented: > > parent { > port { }; > }; Thank you for understanding the situation > But if we have this, does it make sense that of_graph_get_next_ports() > returns the parent, or should it return NULL: > > parent { > /* No ports or port */ > }; Yeah, it should return NULL in this case. > > port = of_graph_get_next_port(parent, NULL); // (A) > > port = of_graph_get_next_port(parent, port); // (B) > > port = of_graph_get_next_port(parent, port); // NULl > > it does not feel right. Why does of_graph_get_next_port() return only > the ports of ports@0? I think it should either return nothing, as there > are no 'port' nodes in the parent, or it should return all the port > nodes from all the ports nodes. As you also mentioned, having "ports" node is optional, and maybe this is the reason you feel uncomfortable on current code, and I can agree about it. If the driver needs to care about multi "ports", it is obvious that the driver cares "ports" node. My opinion is because having "ports" is optional, we want to handle "port" with/without "ports" by same function, especially if it doesn't need to care about multi "ports". I think your opinion (= "port" nodes strictly only in the given parent node) means driver need to care both with/without "ports" node, but the code will be pointlessly complex if it doesn't need to care multi "ports". > bus { > /* our display device */ > display { > port { }; > }; > > /* some odd ports device */ > ports { > }; > }; > > and you use of_graph_get_next_ports() for display, you'll end up getting > the 'ports' node. This is interesting sample, but feels a little forced. If you need to handle display::port, you call port = of_graph_get_next_port(display, NULL); Indeed we will get "ports" node if it calls of_graph_get_next_ports(), but it needs to use unrelated parameters, I think ? ports = of_graph_get_next_ports(bus, display); > > parent { > > ports@0 { > > port@0 { }; > > port@1 { }; > > }; > > ports@1 { > > port@0 { }; > > }; > > }; > > > > of_graph_get_port_count(parent); // 2 = number of ports@0 > > I think the above is a bit surprising, and in my opinion points that > there is a problem. Why does using 'parent' equate to only using > 'ports@0'? Again, I would expect either to get 0 (as there are no 'port' > nodes in parent, or 3. This feature is for the driver which *doesn't* need to care about "ports". /* CASE1 */ parent { port {...}; }; /* CASE2 */ parent { ports { port {...}; }; }; both case (CASE1/2), we can use of_graph_get_port_count(parent); If the driver need to care multi ports, it should use such code, IMO. nr = 0; for_each_of_graph_ports(parent, ports) { nr += of_graph_get_port_count(ports); But of course we can handle it in v2 patch. /* of_graph_get_port_count() cares multi ports inside */ of_graph_get_port_count(parent); Thank you for your help !! Best regards --- Kuninori Morimoto
diff --git a/drivers/of/property.c b/drivers/of/property.c index 164d77cb9445..3b2d09c0376a 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -625,8 +625,76 @@ 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_ports() - get next ports node. + * @parent: pointer to the parent device node + * @ports: current ports node, or NULL to get first + * + * Return: A 'ports' node pointer with refcount incremented. Refcount + * of the passed @prev node is decremented. + */ +struct device_node *of_graph_get_next_ports(struct device_node *parent, + struct device_node *ports) +{ + if (!parent) + return NULL; + + if (!ports) { + ports = of_get_child_by_name(parent, "ports"); + + /* use parent as its ports of this device if it not exist */ + if (!ports) { + ports = parent; + of_node_get(ports); + } + + return ports; + } + + do { + ports = of_get_next_child(parent, ports); + if (!ports) + break; + } while (!of_node_name_eq(ports, "ports")); + + return ports; +} +EXPORT_SYMBOL(of_graph_get_next_ports); + +/** + * 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: A 'port' node pointer with refcount incremented. Refcount + * of the passed @prev node is decremented. + */ +struct device_node *of_graph_get_next_port(struct device_node *parent, + struct device_node *port) +{ + if (!parent) + return NULL; + + if (!port) { + struct device_node *ports __free(device_node) = + of_graph_get_next_ports(parent, NULL); + + return of_get_child_by_name(ports, "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 * @prev: previous endpoint node, or NULL to get first * @@ -823,6 +891,24 @@ unsigned int of_graph_get_endpoint_count(const struct device_node *np) } EXPORT_SYMBOL(of_graph_get_endpoint_count); +/** + * of_graph_get_port_count() - get count of port + * @np: pointer to the parent device node + * + * Return: count of port of this device node + */ +unsigned int of_graph_get_port_count(struct device_node *np) +{ + struct device_node *port = NULL; + int num = 0; + + for_each_of_graph_port(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 a4bea62bfa29..30169b50b042 100644 --- a/include/linux/of_graph.h +++ b/include/linux/of_graph.h @@ -37,14 +37,42 @@ struct of_endpoint { for (child = of_graph_get_next_endpoint(parent, NULL); child != NULL; \ child = of_graph_get_next_endpoint(parent, child)) +/** + * for_each_of_graph_ports - iterate over every ports in a device node + * @parent: parent device node containing ports + * @child: loop variable pointing to the current ports node + * + * When breaking out of the loop, of_node_put(child) has to be called manually. + */ +#define for_each_of_graph_ports(parent, child) \ + for (child = of_graph_get_next_ports(parent, NULL); child != NULL; \ + child = of_graph_get_next_ports(parent, child)) + +/** + * for_each_of_graph_port - iterate over every port in a device or ports node + * @parent: parent device or ports node containing 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_of_graph_port(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); + unsigned int of_graph_get_endpoint_count(const struct device_node *np); +unsigned int of_graph_get_port_count(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_ports(struct device_node *parent, + struct device_node *ports); +struct device_node *of_graph_get_next_port(struct device_node *parent, + struct device_node *port); 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( @@ -73,6 +101,11 @@ static inline unsigned int of_graph_get_endpoint_count(const struct device_node return 0; } +static inline unsigned int of_graph_get_port_count(struct device_node *np) +{ + return 0; +} + static inline struct device_node *of_graph_get_port_by_id( struct device_node *node, u32 id) { @@ -86,6 +119,20 @@ static inline struct device_node *of_graph_get_next_endpoint( return NULL; } +static inline struct device_node *of_graph_get_next_ports( + struct device_node *parent, + struct device_node *previous) +{ + return NULL; +} + +static inline struct device_node *of_graph_get_next_port( + 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) {
We have endpoint base functions - of_graph_get_next_device_endpoint() - of_graph_get_device_endpoint_count() - for_each_of_graph_device_endpoint() Here, for_each_of_graph_device_endpoint() loop finds each endpoints ports { port@0 { (1) endpoint {...}; }; port@1 { (2) endpoint {...}; }; ... }; In above case, it 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" via for_each_of_graph_device_endpoint(). 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 {...}; }; ... }; In the same time, same reason, we want to handle "ports" same as "port". node { => ports@0 { port@0 { endpoint@0 {...}; endpoint@1 {...}; ... }; port@1 { endpoint@0 {...}; endpoint@1 {...}; ... }; ... }; => ports@1 { ... }; }; Add "ports" / "port" base functions. For above case, we can use for_each_of_graph_ports(node, ports) { for_each_of_graph_port(ports, port) { ... } } This loop works in case of "node" doesn't have "ports" also. Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> --- drivers/of/property.c | 86 ++++++++++++++++++++++++++++++++++++++++ include/linux/of_graph.h | 47 ++++++++++++++++++++++ 2 files changed, 133 insertions(+)