[RFC 1/3] firmware: scmi: add a check against availability of protocols

[Etienne CARRIERE]

Hello Akashi-san,

> From: AKASHI Takahiro <takahiro.akashi at linaro.org>
> Sent: Friday, July 28, 2023 02:33
> Subject: [RFC 1/3] firmware: scmi: add a check against availability of protocols
> 
> Now that we have Base protocol support, we will be able to check if a given
> protocol is really supported by the SCMI server (firmware).
> 
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> ---

Reviewed-by: Etienne Carriere <etienne.carriere at foss.st.com>

>  drivers/firmware/scmi/scmi_agent-uclass.c | 41 +++++++++++++++++++++--
>  1 file changed, 38 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/firmware/scmi/scmi_agent-uclass.c b/drivers/firmware/scmi/scmi_agent-uclass.c
> index 91cb172f3005..9494dca95bca 100644
> --- a/drivers/firmware/scmi/scmi_agent-uclass.c
> +++ b/drivers/firmware/scmi/scmi_agent-uclass.c
> @@ -44,6 +44,38 @@ static const struct error_code scmi_linux_errmap[] = {
>   */
>  struct udevice *scmi_agent;
> 
> +/**
> + * scmi_protocol_is_supported - check availability of protocol
> + * @dev:       SCMI agent device
> + * @proto_id:  Identifier of protocol
> + *
> + * check if the protocol, @proto_id, is provided by the SCMI agent,
> + * @dev.
> + *
> + * Return:     0 on success, error code otherwise
> + */
> +static bool scmi_protocol_is_supported(struct udevice *dev,
> +                                      enum scmi_std_protocol proto_id)
> +{
> +       struct scmi_agent_priv *priv;
> +       int i;
> +
> +       if (proto_id == SCMI_PROTOCOL_ID_BASE)
> +               return true;
> +
> +       priv = dev_get_uclass_plat(dev);
> +       if (!priv) {
> +               dev_err(dev, "No priv data found\n");
> +               return false;
> +       }
> +
> +       for (i = 0; i < priv->num_protocols; i++)
> +               if (priv->protocols[i] == proto_id)
> +                       return true;
> +
> +       return false;
> +}
> +
>  struct udevice *scmi_get_protocol(struct udevice *dev,
>                                   enum scmi_std_protocol id)
>  {
> @@ -372,15 +404,18 @@ static int scmi_bind_protocols(struct udevice *dev)
>                 name = ofnode_get_name(node);
>                 switch (protocol_id) {
>                 case SCMI_PROTOCOL_ID_CLOCK:
> -                       if (CONFIG_IS_ENABLED(CLK_SCMI))
> +                       if (CONFIG_IS_ENABLED(CLK_SCMI) &&
> +                           scmi_protocol_is_supported(dev, protocol_id))
>                                 drv = DM_DRIVER_GET(scmi_clock);
>                         break;
>                 case SCMI_PROTOCOL_ID_RESET_DOMAIN:
> -                       if (IS_ENABLED(CONFIG_RESET_SCMI))
> +                       if (IS_ENABLED(CONFIG_RESET_SCMI) &&
> +                           scmi_protocol_is_supported(dev, protocol_id))
>                                 drv = DM_DRIVER_GET(scmi_reset_domain);
>                         break;
>                 case SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN:
> -                       if (IS_ENABLED(CONFIG_DM_REGULATOR_SCMI)) {
> +                       if (IS_ENABLED(CONFIG_DM_REGULATOR_SCMI) &&
> +                           scmi_protocol_is_supported(dev, protocol_id)) {
>                                 node = ofnode_find_subnode(node, "regulators");
>                                 if (!ofnode_valid(node)) {
>                                         dev_err(dev, "no regulators node\n");
> --
> 2.41.0
> 
>