firmware: arm_scmi: Add SCMI v3.1 System Power extensions

Add support for SCMIv3.1 System Power optional timeout field while
dispatching SYSTEM_POWER_STATE_NOTIFIER notification.

Link: https://lore.kernel.org/r/20220704101933.2981635-3-cristian.marussi@arm.comSigned-off-by: NCristian Marussi <cristian.marussi@arm.com>
Signed-off-by: NSudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/system.c

@@ -27,10 +27,12 @@ struct scmi_system_power_state_notifier_payld {
 	__le32 agent_id;
 	__le32 flags;
 	__le32 system_state;
+	__le32 timeout;
 };
 
 struct scmi_system_info {
 	u32 version;
+	bool graceful_timeout_supported;
 };
 
 static int scmi_system_request_notify(const struct scmi_protocol_handle *ph,
@@ -72,17 +74,27 @@ scmi_system_fill_custom_report(const struct scmi_protocol_handle *ph,
 			       const void *payld, size_t payld_sz,
 			       void *report, u32 *src_id)
 {
+	size_t expected_sz;
 	const struct scmi_system_power_state_notifier_payld *p = payld;
 	struct scmi_system_power_state_notifier_report *r = report;
+	struct scmi_system_info *pinfo = ph->get_priv(ph);
 
+	expected_sz = pinfo->graceful_timeout_supported ?
+			sizeof(*p) : sizeof(*p) - sizeof(__le32);
 	if (evt_id != SCMI_EVENT_SYSTEM_POWER_STATE_NOTIFIER ||
-	    sizeof(*p) != payld_sz)
+	    payld_sz != expected_sz)
 		return NULL;
 
 	r->timestamp = timestamp;
 	r->agent_id = le32_to_cpu(p->agent_id);
 	r->flags = le32_to_cpu(p->flags);
 	r->system_state = le32_to_cpu(p->system_state);
+	if (pinfo->graceful_timeout_supported &&
+	    r->system_state == SCMI_SYSTEM_SHUTDOWN &&
+	    SCMI_SYSPOWER_IS_REQUEST_GRACEFUL(r->flags))
+		r->timeout = le32_to_cpu(p->timeout);
+	else
+		r->timeout = 0x00;
 	*src_id = 0;
 
 	return r;
@@ -129,6 +141,9 @@ static int scmi_system_protocol_init(const struct scmi_protocol_handle *ph)
 		return -ENOMEM;
 
 	pinfo->version = version;
+	if (PROTOCOL_REV_MAJOR(pinfo->version) >= 0x2)
+		pinfo->graceful_timeout_supported = true;
+
 	return ph->set_priv(ph, pinfo);
 }
 

include/linux/scmi_protocol.h

@@ -781,8 +781,10 @@ struct scmi_clock_rate_notif_report {
 struct scmi_system_power_state_notifier_report {
 	ktime_t		timestamp;
 	unsigned int	agent_id;
+#define SCMI_SYSPOWER_IS_REQUEST_GRACEFUL(flags)	((flags) & BIT(0))
 	unsigned int	flags;
 	unsigned int	system_state;
+	unsigned int	timeout;
 };
 
 struct scmi_perf_limits_report {