[PATCH v6 06/12] firmware: arm_scmi: Extend powercap report to include MAI

[Philip Radford <philip.radford@arm.com>]

Extend scmi_powercap_meas_changed_report to include MAI change
notifications.

Signed-off-by: Philip Radford <philip.radford@arm.com>
---
V5->V6
- Re-worded existing comment for POWERCAP_MEASUREMENTS_NOTIFY
- Added define for V2/V3 sizes
- Used new definitions
---
 drivers/firmware/arm_scmi/powercap.c | 28 +++++++++++++++-------------
 include/linux/scmi_protocol.h        |  1 +
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/firmware/arm_scmi/powercap.c b/drivers/firmware/arm_scmi/powercap.c
index 1d1188e98d49..fdfaf03277ab 100644
--- a/drivers/firmware/arm_scmi/powercap.c
+++ b/drivers/firmware/arm_scmi/powercap.c
@@ -11,6 +11,7 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/scmi_protocol.h>
+#include <linux/stddef.h>
 
 #include <trace/events/scmi.h>
 
@@ -21,6 +22,8 @@
 #define SCMI_PROTOCOL_SUPPORTED_VERSION		0x30000
 
 #define CPL0	0
+#define SZ_V2 (sizeof(struct scmi_powercap_meas_changed_notify_payld))
+#define SZ_V3 (SZ_V2 - sizeof(__le32))
 
 enum scmi_powercap_protocol_cmd {
 	POWERCAP_DOMAIN_ATTRIBUTES = 0x3,
@@ -164,6 +167,7 @@ struct scmi_powercap_meas_changed_notify_payld {
 	__le32 agent_id;
 	__le32 domain_id;
 	__le32 power;
+	__le32 mai;
 };
 
 struct scmi_msg_powercap_cpc {
@@ -1201,24 +1205,18 @@ static int scmi_powercap_notify(const struct scmi_protocol_handle *ph,
 		struct scmi_msg_powercap_notify_thresh *notify;
 
 		/*
-		 * Note that we have to pick the most recently configured
-		 * thresholds to build a proper POWERCAP_MEASUREMENTS_NOTIFY
-		 * enable request and we fail, complaining, if no thresholds
-		 * were ever set, since this is an indication the API has been
-		 * used wrongly.
+		 * Build the POWERCAP_MEASUREMENTS_NOTIFY enable request using the
+		 * most recently configured thresholds.
+		 *
+		 * The absence of thresholds is not considered an error:
+		 * notifications can still be generated to report MAI changes, even
+		 * when low and high are set to zero.
 		 */
 		ret = scmi_powercap_measurements_threshold_get(ph, domain,
 							       &low, &high);
 		if (ret)
 			return ret;
 
-		if (enable && !low && !high) {
-			dev_err(ph->dev,
-				"Invalid Measurements Notify thresholds: %u/%u\n",
-				low, high);
-			return -EINVAL;
-		}
-
 		ret = ph->xops->xfer_get_init(ph, message_id,
 					      sizeof(*notify), 0, &t);
 		if (ret)
@@ -1334,13 +1332,17 @@ scmi_powercap_fill_custom_report(const struct scmi_protocol_handle *ph,
 		const struct scmi_powercap_meas_changed_notify_payld *p = payld;
 		struct scmi_powercap_meas_changed_report *r = report;
 
-		if (sizeof(*p) != payld_sz)
+		if (payld_sz != SZ_V2 && payld_sz != SZ_V3)
 			break;
 
 		r->timestamp = timestamp;
 		r->agent_id = le32_to_cpu(p->agent_id);
 		r->domain_id = le32_to_cpu(p->domain_id);
 		r->power = le32_to_cpu(p->power);
+		r->mai = 0;
+		if (payld_sz == SZ_V3 && PROTOCOL_REV_MAJOR(ph->version) >= 0x3)
+			r->mai = le32_to_cpu(p->mai);
+
 		*src_id = r->domain_id;
 		rep = r;
 		break;
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 299fa8499b3f..d0f6c0102559 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -1134,5 +1134,6 @@ struct scmi_powercap_meas_changed_report {
 	unsigned int	agent_id;
 	unsigned int	domain_id;
 	unsigned int	power;
+	unsigned int	mai;
 };
 #endif /* _LINUX_SCMI_PROTOCOL_H */
-- 
2.47.3