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SubjectRe: [PATCH v2 09/10] coresight: Cleanup coresight DT bindings
Hello,

On Thu, Jul 19, 2018 at 11:55:13AM +0100, Suzuki K Poulose wrote:
> The coresight drivers relied on default bindings for graph
> in DT, while reusing the "reg" field of the "ports" to indicate
> the actual hardware port number for the connections. This can
> cause duplicate ports with same addresses, but different
> direction. However, with the rules getting stricter w.r.t to the

It's only a matter of time before someone calls you out on the "w.r.t". Better
to simply spell it out.

> address mismatch with the label, it is no longer possible to use
> the port address field for the hardware port number.
>
> This patch introduces new DT binding rules for coresight
> components, based on the same generic DT graph bindings, but
> avoiding the address duplication.
>
> - All output ports must be specified under a child node with
> name "out-ports".
> - All input ports must be specified under a childe node with
> name "in-ports".
> - Port address should match the hardware port number.
>
> The support for legacy bindings is retained, with a warning.
>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: Rob Herring <robh@kernel.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> .../devicetree/bindings/arm/coresight.txt | 91 ++++++++++----------
> drivers/hwtracing/coresight/of_coresight.c | 97 +++++++++++++++++++---
> 2 files changed, 129 insertions(+), 59 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
> index 8e21512..f39d2c6 100644
> --- a/Documentation/devicetree/bindings/arm/coresight.txt
> +++ b/Documentation/devicetree/bindings/arm/coresight.txt
> @@ -104,19 +104,9 @@ The connections must be described via generic DT graph bindings as described
> by the "bindings/graph.txt", where each "port" along with an "endpoint"
> component represents a hardware port and the connection.
>
> -Since it is possible to have multiple connections for any coresight component
> -with a specific direction of data flow, each connection must define the
> -following properties to uniquely identify the connection details.
> -
> - * Direction of the data flow w.r.t the component :

Same here.

With those changes:

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> - Each input port must have the following property defined at the "endpoint"
> - for the port.
> - "slave-mode"
> -
> - * Hardware Port number at the component:
> - - The hardware port number is assumed to be the address of the "port"
> - component.
> -
> + * All output ports must be listed inside a child node named "out-ports"
> + * All input ports must be listed inside a child node named "in-ports".
> + * Port address must match the hardware port number.
>
> Example:
>
> @@ -127,10 +117,11 @@ Example:
>
> clocks = <&oscclk6a>;
> clock-names = "apb_pclk";
> - port {
> - etb_in_port: endpoint@0 {
> - slave-mode;
> - remote-endpoint = <&replicator_out_port0>;
> + in-ports {
> + port {
> + etb_in_port: endpoint@0 {
> + remote-endpoint = <&replicator_out_port0>;
> + };
> };
> };
> };
> @@ -141,10 +132,11 @@ Example:
>
> clocks = <&oscclk6a>;
> clock-names = "apb_pclk";
> - port {
> - tpiu_in_port: endpoint@0 {
> - slave-mode;
> - remote-endpoint = <&replicator_out_port1>;
> + out-ports {
> + port {
> + tpiu_in_port: endpoint@0 {
> + remote-endpoint = <&replicator_out_port1>;
> + };
> };
> };
> };
> @@ -185,7 +177,7 @@ Example:
> */
> compatible = "arm,coresight-replicator";
>
> - ports {
> + out-ports {
> #address-cells = <1>;
> #size-cells = <0>;
>
> @@ -203,12 +195,11 @@ Example:
> remote-endpoint = <&tpiu_in_port>;
> };
> };
> + };
>
> - /* replicator input port */
> - port@2 {
> - reg = <0>;
> + in-ports {
> + port {
> replicator_in_port0: endpoint {
> - slave-mode;
> remote-endpoint = <&funnel_out_port0>;
> };
> };
> @@ -221,40 +212,36 @@ Example:
>
> clocks = <&oscclk6a>;
> clock-names = "apb_pclk";
> - ports {
> - #address-cells = <1>;
> - #size-cells = <0>;
> -
> - /* funnel output port */
> - port@0 {
> - reg = <0>;
> + out-ports {
> + port {
> funnel_out_port0: endpoint {
> remote-endpoint =
> <&replicator_in_port0>;
> };
> };
> + };
>
> - /* funnel input ports */
> - port@1 {
> + in-ports {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + port@0 {
> reg = <0>;
> funnel_in_port0: endpoint {
> - slave-mode;
> remote-endpoint = <&ptm0_out_port>;
> };
> };
>
> - port@2 {
> + port@1 {
> reg = <1>;
> funnel_in_port1: endpoint {
> - slave-mode;
> remote-endpoint = <&ptm1_out_port>;
> };
> };
>
> - port@3 {
> + port@2 {
> reg = <2>;
> funnel_in_port2: endpoint {
> - slave-mode;
> remote-endpoint = <&etm0_out_port>;
> };
> };
> @@ -270,9 +257,11 @@ Example:
> cpu = <&cpu0>;
> clocks = <&oscclk6a>;
> clock-names = "apb_pclk";
> - port {
> - ptm0_out_port: endpoint {
> - remote-endpoint = <&funnel_in_port0>;
> + out-ports {
> + port {
> + ptm0_out_port: endpoint {
> + remote-endpoint = <&funnel_in_port0>;
> + };
> };
> };
> };
> @@ -284,9 +273,11 @@ Example:
> cpu = <&cpu1>;
> clocks = <&oscclk6a>;
> clock-names = "apb_pclk";
> - port {
> - ptm1_out_port: endpoint {
> - remote-endpoint = <&funnel_in_port1>;
> + out-ports {
> + port {
> + ptm1_out_port: endpoint {
> + remote-endpoint = <&funnel_in_port1>;
> + };
> };
> };
> };
> @@ -300,9 +291,11 @@ Example:
>
> clocks = <&soc_smc50mhz>;
> clock-names = "apb_pclk";
> - port {
> - stm_out_port: endpoint {
> - remote-endpoint = <&main_funnel_in_port2>;
> + out-ports {
> + port {
> + stm_out_port: endpoint {
> + remote-endpoint = <&main_funnel_in_port2>;
> + };
> };
> };
> };
> diff --git a/drivers/hwtracing/coresight/of_coresight.c b/drivers/hwtracing/coresight/of_coresight.c
> index f9e2169..2178734 100644
> --- a/drivers/hwtracing/coresight/of_coresight.c
> +++ b/drivers/hwtracing/coresight/of_coresight.c
> @@ -45,13 +45,13 @@ of_coresight_get_endpoint_device(struct device_node *endpoint)
> endpoint, of_dev_node_match);
> }
>
> -static inline bool of_coresight_ep_is_input(struct device_node *ep)
> +static inline bool of_coresight_legacy_ep_is_input(struct device_node *ep)
> {
> return of_property_read_bool(ep, "slave-mode");
> }
>
> -static void of_coresight_get_ports(const struct device_node *node,
> - int *nr_inport, int *nr_outport)
> +static void of_coresight_get_ports_legacy(const struct device_node *node,
> + int *nr_inport, int *nr_outport)
> {
> struct device_node *ep = NULL;
> int in = 0, out = 0;
> @@ -61,7 +61,7 @@ static void of_coresight_get_ports(const struct device_node *node,
> if (!ep)
> break;
>
> - if (of_coresight_ep_is_input(ep))
> + if (of_coresight_legacy_ep_is_input(ep))
> in++;
> else
> out++;
> @@ -72,6 +72,67 @@ static void of_coresight_get_ports(const struct device_node *node,
> *nr_outport = out;
> }
>
> +static struct device_node *of_coresight_get_port_parent(struct device_node *ep)
> +{
> + struct device_node *parent = of_graph_get_port_parent(ep);
> +
> + /*
> + * Skip one-level up to the real device node, if we
> + * are using the new bindings.
> + */
> + if (!of_node_cmp(parent->name, "in-ports") ||
> + !of_node_cmp(parent->name, "out-ports"))
> + parent = of_get_next_parent(parent);
> +
> + return parent;
> +}
> +
> +static inline struct device_node *
> +of_coresight_get_input_ports_node(const struct device_node *node)
> +{
> + return of_get_child_by_name(node, "in-ports");
> +}
> +
> +static inline struct device_node *
> +of_coresight_get_output_ports_node(const struct device_node *node)
> +{
> + return of_get_child_by_name(node, "out-ports");
> +}
> +
> +static inline int
> +of_coresight_count_ports(struct device_node *port_parent)
> +{
> + int i = 0;
> + struct device_node *ep = NULL;
> +
> + while ((ep = of_graph_get_next_endpoint(port_parent, ep)))
> + i++;
> + return i;
> +}
> +
> +static void of_coresight_get_ports(const struct device_node *node,
> + int *nr_inport, int *nr_outport)
> +{
> + struct device_node *input_ports = NULL, *output_ports = NULL;
> +
> + input_ports = of_coresight_get_input_ports_node(node);
> + output_ports = of_coresight_get_output_ports_node(node);
> +
> + if (input_ports || output_ports) {
> + if (input_ports) {
> + *nr_inport = of_coresight_count_ports(input_ports);
> + of_node_put(input_ports);
> + }
> + if (output_ports) {
> + *nr_outport = of_coresight_count_ports(output_ports);
> + of_node_put(output_ports);
> + }
> + } else {
> + /* Fall back to legacy DT bindings parsing */
> + of_coresight_get_ports_legacy(node, nr_inport, nr_outport);
> + }
> +}
> +
> static int of_coresight_alloc_memory(struct device *dev,
> struct coresight_platform_data *pdata)
> {
> @@ -136,7 +197,7 @@ static int of_coresight_parse_endpoint(struct device *dev,
> rep = of_graph_get_remote_endpoint(ep);
> if (!rep)
> break;
> - rparent = of_graph_get_port_parent(rep);
> + rparent = of_coresight_get_port_parent(rep);
> if (!rparent)
> break;
> if (of_graph_parse_endpoint(rep, &rendpoint))
> @@ -176,6 +237,8 @@ of_get_coresight_platform_data(struct device *dev,
> struct coresight_platform_data *pdata;
> struct coresight_connection *conn;
> struct device_node *ep = NULL;
> + const struct device_node *parent = NULL;
> + bool legacy_binding = false;
>
> pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> if (!pdata)
> @@ -196,14 +259,28 @@ of_get_coresight_platform_data(struct device *dev,
> if (ret)
> return ERR_PTR(ret);
>
> + parent = of_coresight_get_output_ports_node(node);
> + /*
> + * If the DT uses obsoleted bindings, the ports are listed
> + * under the device and we need to filter out the input
> + * ports.
> + */
> + if (!parent) {
> + legacy_binding = true;
> + parent = node;
> + dev_warn_once(dev, "Uses obsolete Coresight DT bindings\n");
> + }
> +
> conn = pdata->conns;
> - /* Iterate through each port to discover topology */
> - while ((ep = of_graph_get_next_endpoint(node, ep))) {
> +
> + /* Iterate through each output port to discover topology */
> + while ((ep = of_graph_get_next_endpoint(parent, ep))) {
> /*
> - * No need to deal with input ports, processing for as
> - * processing for output ports will deal with them.
> + * Legacy binding mixes input/output ports under the
> + * same parent. So, skip the input ports if we are dealing
> + * with legacy binding.
> */
> - if (of_coresight_ep_is_input(ep))
> + if (legacy_binding && of_coresight_legacy_ep_is_input(ep))
> continue;
>
> ret = of_coresight_parse_endpoint(dev, ep, &conn);
> --
> 2.7.4
>

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