Re: [PATCH v3 1/4] firmware: arm_scmi: Add Voltage Domain Support

From: Etienne Carriere
Date: Thu Oct 29 2020 - 07:22:32 EST

On Wed, 28 Oct 2020 at 21:44, Cristian Marussi <cristian.marussi@xxxxxxx> wrote:
>
> On Wed, Oct 28, 2020 at 03:29:57PM +0100, Etienne Carriere wrote:
> > Hi Cristian,
> >
> > Some remaining minor comments see below.
> > FYI I've successfully tested this series (the 4 patches).
> >
>
> Hi
>
> Thanks a lot !
>
> Replies inline down below.
>
> [snip]
> > > +struct scmi_msg_cmd_config_set {
> > > + __le32 domain_id;
> > > + __le32 config;
> > > +};
> > > +
> > > +struct scmi_msg_cmd_level_set {
> > > + __le32 domain_id;
> > > + __le32 flags;
> > > + __le32 voltage_level;
> > > +};
> > > +
> > > +struct voltage_info {
> > > + u32 version;
> > > + u16 num_domains;
> >
> > Could be an unsigned int.
> >
>
> I tend to use fixed size types matching the protocols messages sizing on
> the internal while exposing non-fixed size types in scmi_protocol.h like
> in scmi_voltage_info, but these indeed are values exposed directly to
> the user afterwards. Any other reason to prefer non-fixed size here ?

I think fixed size should be used where really needed.
Since in this structure you're quite abstracted from the protocol, a generic
type is preferred I think.

Regards,
Etienne

>
> > > + struct scmi_voltage_info **domains;
> > > +};
> > > +
> > > +static int scmi_protocol_attributes_get(const struct scmi_handle *handle,
> > > + struct voltage_info *vinfo)
> > > +{
> > > + int ret;
> > > + struct scmi_xfer *t;
> > > + struct scmi_msg_resp_protocol_attributes *resp;
> > > +
> > > + ret = scmi_xfer_get_init(handle, PROTOCOL_ATTRIBUTES,
> > > + SCMI_PROTOCOL_VOLTAGE, 0, sizeof(*resp), &t);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + resp = t->rx.buf;
> > > + ret = scmi_do_xfer(handle, t);
> > > + if (!ret)
> > > + vinfo->num_domains =
> > > + NUM_VOLTAGE_DOMAINS(le32_to_cpu(resp->attr));
> > > +
> > > + scmi_xfer_put(handle, t);
> > > + return ret;
> > > +}
> > > +
> > > +static inline int scmi_init_voltage_levels(struct device *dev,
> >
> > Should remove this inline attribute.
> >
>
> Ah right, I removed one and left this. I'll do.
>
> > > + struct scmi_voltage_info *v,
> > > + u32 flags, u32 num_returned,
> > > + u32 num_remaining)
>
> [snip]
>
> > > +DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(SCMI_PROTOCOL_VOLTAGE, voltage)
> > > diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
> > > index 9cd312a1ff92..181fdebc2793 100644
> > > --- a/include/linux/scmi_protocol.h
> > > +++ b/include/linux/scmi_protocol.h
> > > @@ -209,6 +209,64 @@ struct scmi_reset_ops {
> > > int (*deassert)(const struct scmi_handle *handle, u32 domain);
> > > };
> > >
> > > +/**
> > > + * struct scmi_voltage_info - describe one available SCMI Voltage Domain
> > > + *
> > > + * @id: the domain ID as advertised by the platform
> > > + * @segmented: defines the layout of the entries of array @levels_uv.
> > > + * - when True the entries are to be interpreted as triplets,
> > > + * each defining a segment representing a range of equally
> > > + * space voltages: <lowest_volts>, <highest_volt>, <step_uV>
> > > + * - when False the entries simply represent a single discrete
> > > + * supported voltage level
> > > + * @negative_volts_allowed: True if any of the entries of @levels_uv represent
> > > + * a negative voltage.
> > > + * @attributes: represents Voltage Domain advertised attributes
> > > + * @name: name assigned to the Voltage Domain by platform
> > > + * @num_levels: number of total entries in @levels_uv.
> > > + * @levels_uv: array of entries describing the available voltage levels for
> > > + * this domain.
> > > + */
> > > +struct scmi_voltage_info {
> > > + unsigned int id;
> > > + bool segmented;
> > > +#define SCMI_VOLTAGE_SEGMENT_LOW 0
> > > +#define SCMI_VOLTAGE_SEGMENT_HIGH 1
> > > +#define SCMI_VOLTAGE_SEGMENT_STEP 2
> >
> > Maybe move these macros before 'int *level_us;' as these are indices
> > in that array.
> >
>
> Right, I'll do.
>
> Thanks
>
> Cristian
>
> > > + bool negative_volts_allowed;
> > > + unsigned int attributes;
> > > + char name[SCMI_MAX_STR_SIZE];
> > > + unsigned int num_levels;
> > > + int *levels_uv;
> > > +};
> > > +
> > > +/**
> > > + * struct scmi_voltage_ops - represents the various operations provided
> > > + * by SCMI Voltage Protocol
> > > + *
> > > + * @num_domains_get: get the count of voltage domains provided by SCMI
> > > + * @info_get: get the information of the specified domain
> > > + * @config_set: set the config for the specified domain
> > > + * @config_get: get the config of the specified domain
> > > + * @level_set: set the voltage level for the specified domain
> > > + * @level_get: get the voltage level of the specified domain
> > > + */
> > > +struct scmi_voltage_ops {
> > > + int (*num_domains_get)(const struct scmi_handle *handle);
> > > + const struct scmi_voltage_info __must_check *(*info_get)
> > > + (const struct scmi_handle *handle, u32 domain_id);
> > > + int (*config_set)(const struct scmi_handle *handle, u32 domain_id,
> > > + u32 config);
> > > +#define SCMI_VOLTAGE_ARCH_STATE_OFF 0x0
> > > +#define SCMI_VOLTAGE_ARCH_STATE_ON 0x7
> > > + int (*config_get)(const struct scmi_handle *handle, u32 domain_id,
> > > + u32 *config);
> > > + int (*level_set)(const struct scmi_handle *handle, u32 domain_id,
> > > + u32 flags, s32 volt_uV);
> > > + int (*level_get)(const struct scmi_handle *handle, u32 domain_id,
> > > + s32 *volt_uV);
> > > +};
> > > +
> > > /**
> > > * struct scmi_notify_ops - represents notifications' operations provided by
> > > * SCMI core
> > > @@ -262,6 +320,7 @@ struct scmi_notify_ops {
> > > * @clk_ops: pointer to set of clock protocol operations
> > > * @sensor_ops: pointer to set of sensor protocol operations
> > > * @reset_ops: pointer to set of reset protocol operations
> > > + * @voltage_ops: pointer to set of voltage protocol operations
> > > * @notify_ops: pointer to set of notifications related operations
> > > * @perf_priv: pointer to private data structure specific to performance
> > > * protocol(for internal use only)
> > > @@ -273,6 +332,8 @@ struct scmi_notify_ops {
> > > * protocol(for internal use only)
> > > * @reset_priv: pointer to private data structure specific to reset
> > > * protocol(for internal use only)
> > > + * @voltage_priv: pointer to private data structure specific to voltage
> > > + * protocol(for internal use only)
> > > * @notify_priv: pointer to private data structure specific to notifications
> > > * (for internal use only)
> > > */
> > > @@ -284,6 +345,7 @@ struct scmi_handle {
> > > const struct scmi_power_ops *power_ops;
> > > const struct scmi_sensor_ops *sensor_ops;
> > > const struct scmi_reset_ops *reset_ops;
> > > + const struct scmi_voltage_ops *voltage_ops;
> > > const struct scmi_notify_ops *notify_ops;
> > > /* for protocol internal use */
> > > void *perf_priv;
> > > @@ -291,6 +353,7 @@ struct scmi_handle {
> > > void *power_priv;
> > > void *sensor_priv;
> > > void *reset_priv;
> > > + void *voltage_priv;
> > > void *notify_priv;
> > > void *system_priv;
> > > };
> > > @@ -303,6 +366,7 @@ enum scmi_std_protocol {
> > > SCMI_PROTOCOL_CLOCK = 0x14,
> > > SCMI_PROTOCOL_SENSOR = 0x15,
> > > SCMI_PROTOCOL_RESET = 0x16,
> > > + SCMI_PROTOCOL_VOLTAGE = 0x17,
> > > };
> > >
> > > enum scmi_system_events {
> > > --
> > > 2.17.1
> > >