diff options
| -rw-r--r-- | drivers/firmware/arm_scmi/driver.c | 93 | ||||
| -rw-r--r-- | drivers/firmware/arm_scmi/protocols.h | 4 |
2 files changed, 81 insertions, 16 deletions
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 5caa9191a8d1..094cfcf51d28 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -2113,6 +2113,76 @@ static int scmi_protocol_version_negotiate(struct scmi_protocol_handle *ph) } /** + * scmi_protocol_version_initialize - Initialize protocol version + * @dev: A device reference. + * @pi: A reference to the protocol instance being initialized + * + * At first retrieve the newest protocol version supported by the platform for + * this specific protoocol. + * + * Negotiation is attempted only when the platform advertised a protocol + * version newer than the most recent version known to this agent, since + * backward compatibility is NOT assured in general between versions. + * + * Failing to negotiate a fallback version or to query supported version at + * all will result in an attempt to use the newest version known to this agent + * even though compatibility is NOT assured. + * + * Versions are defined as: + * + * pi->version: the version supported by the platform as returned by the query. + * pi->proto->supported_version: the newest version supported by this agent + * for this protocol. + * pi->negotiated_version: The version successfully negotiated with the platform. + * ph->version: The final version effectively chosen for this session. + */ +static void scmi_protocol_version_initialize(struct device *dev, + struct scmi_protocol_instance *pi) +{ + struct scmi_protocol_handle *ph = &pi->ph; + int ret; + + /* + * Query and store platform supported protocol version: this is usually + * the newest version the platfom can support. + */ + ret = version_get(ph, &pi->version); + if (ret) { + dev_warn(dev, + "Failed to query supported version for protocol 0x%X.\n", + pi->proto->id); + goto best_effort; + } + + /* Need to negotiate at all ? */ + if (pi->version <= pi->proto->supported_version) { + ph->version = pi->version; + return; + } + + /* Attempt negotiation */ + ret = scmi_protocol_version_negotiate(ph); + if (!ret) { + ph->version = pi->negotiated_version; + dev_info(dev, + "Protocol 0x%X successfully negotiated version 0x%X\n", + pi->proto->id, ph->version); + return; + } + + dev_warn(dev, + "Detected UNSUPPORTED higher version 0x%X for protocol 0x%X.\n", + pi->version, pi->proto->id); + +best_effort: + /* Fallback to use newest version known to this agent */ + ph->version = pi->proto->supported_version; + dev_warn(dev, + "Trying version 0x%X. Backward compatibility is NOT assured.\n", + ph->version); +} + +/** * scmi_alloc_init_protocol_instance - Allocate and initialize a protocol * instance descriptor. * @info: The reference to the related SCMI instance. @@ -2157,6 +2227,13 @@ scmi_alloc_init_protocol_instance(struct scmi_info *info, pi->ph.set_priv = scmi_set_protocol_priv; pi->ph.get_priv = scmi_get_protocol_priv; refcount_set(&pi->users, 1); + + /* + * Initialize effectively used protocol version performing any + * possibly needed negotiations. + */ + scmi_protocol_version_initialize(handle->dev, pi); + /* proto->init is assured NON NULL by scmi_protocol_register */ ret = pi->proto->instance_init(&pi->ph); if (ret) @@ -2184,22 +2261,6 @@ scmi_alloc_init_protocol_instance(struct scmi_info *info, devres_close_group(handle->dev, pi->gid); dev_dbg(handle->dev, "Initialized protocol: 0x%X\n", pi->proto->id); - if (pi->version > proto->supported_version) { - ret = scmi_protocol_version_negotiate(&pi->ph); - if (!ret) { - dev_info(handle->dev, - "Protocol 0x%X successfully negotiated version 0x%X\n", - proto->id, pi->negotiated_version); - } else { - dev_warn(handle->dev, - "Detected UNSUPPORTED higher version 0x%X for protocol 0x%X.\n", - pi->version, pi->proto->id); - dev_warn(handle->dev, - "Trying version 0x%X. Backward compatibility is NOT assured.\n", - pi->proto->supported_version); - } - } - return pi; clean: diff --git a/drivers/firmware/arm_scmi/protocols.h b/drivers/firmware/arm_scmi/protocols.h index d62c4469d1fd..2766c2b822b5 100644 --- a/drivers/firmware/arm_scmi/protocols.h +++ b/drivers/firmware/arm_scmi/protocols.h @@ -159,6 +159,9 @@ struct scmi_proto_helpers_ops; * struct scmi_protocol_handle - Reference to an initialized protocol instance * * @dev: A reference to the associated SCMI instance device (handle->dev). + * @version: The protocol version currently effectively in use by this + * initialized instance of the protocol as determined at the end of + * any possibly needed negotiations performed by the core. * @xops: A reference to a struct holding refs to the core xfer operations that * can be used by the protocol implementation to generate SCMI messages. * @set_priv: A method to set protocol private data for this instance. @@ -177,6 +180,7 @@ struct scmi_proto_helpers_ops; */ struct scmi_protocol_handle { struct device *dev; + unsigned int version; const struct scmi_xfer_ops *xops; const struct scmi_proto_helpers_ops *hops; int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv, |