Merge tag 'scmi-updates-6.17' of https://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into soc/drivers

Arm SCMI updates for v6.17

1. A fix is introduced to correct turbo frequency marking for 64-bit
   devices with sustained frequencies over 4GHz, ensuring accurate turbo
   frequency identification.

2. Debug capabilities are being improved by introducing in-flight transfer
   tracking using debug counters, which help diagnose transfer congestion
   and behavior. Additional tracepoints are added to log in-flight counts
   at transfer begin and end, offering better runtime insight. The debug
   counters now support decrement operations using a newly added
   scmi_dec_count helper, making counter tracking symmetric and more robust.

3. A race condition in suspend-resume logic is being resolved by ensuring
   SCMI_SYSPOWER_IDLE state is set early during resume, improving suspend
   reliability under certain conditions. New suspend and resume operations
   are added to the scmi_bus_type to enable finer power management control
   for SCMI-based devices.

4. Finally enhancements are also made to avoid registering notifiers for
   events that a platform does not support, reducing unnecessary overhead
   by checking for unsupported event types during protocolinitialization.

* tag 'scmi-updates-6.17' of https://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  firmware: arm_scmi: Convert to SYSTEM_SLEEP_PM_OPS
  firmware: arm_scmi: Avoid notifier registration for unsupported events
  firmware: arm_scmi: power_control: Ensure SCMI_SYSPOWER_IDLE is set early during resume
  firmware: arm_scmi: Add power management operations to SCMI bus
  include: trace:  Add tracepoint support for inflight xfer count
  firmware: arm_scmi: Track number of inflight SCMI transfers
  firmware: arm_scmi: Add support for debug counter decrement
  firmware: arm_scmi: Fix up turbo frequencies selection

Link: https://lore.kernel.org/r/20250709122907.1171913-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/firmware/arm_scmi/bus.c

@@ -323,6 +323,31 @@ static struct attribute *scmi_device_attributes_attrs[] = {
 };
 ATTRIBUTE_GROUPS(scmi_device_attributes);
 
+static int scmi_pm_suspend(struct device *dev)
+{
+	const struct device_driver *drv = dev->driver;
+
+	if (drv && drv->pm && drv->pm->suspend)
+		return drv->pm->suspend(dev);
+
+	return 0;
+}
+
+static int scmi_pm_resume(struct device *dev)
+{
+	const struct device_driver *drv = dev->driver;
+
+	if (drv && drv->pm && drv->pm->resume)
+		return drv->pm->resume(dev);
+
+	return 0;
+}
+
+static const struct dev_pm_ops scmi_dev_pm_ops = {
+	.suspend = pm_sleep_ptr(scmi_pm_suspend),
+	.resume = pm_sleep_ptr(scmi_pm_resume),
+};
+
 const struct bus_type scmi_bus_type = {
 	.name =	"scmi_protocol",
 	.match = scmi_dev_match,
@@ -330,6 +355,7 @@ const struct bus_type scmi_bus_type = {
 	.remove = scmi_dev_remove,
 	.uevent	= scmi_device_uevent,
 	.dev_groups = scmi_device_attributes_groups,
+	.pm = &scmi_dev_pm_ops,
 };
 EXPORT_SYMBOL_GPL(scmi_bus_type);
 

drivers/firmware/arm_scmi/common.h

@@ -305,6 +305,7 @@ enum debug_counters {
 	ERR_MSG_INVALID,
 	ERR_MSG_NOMEM,
 	ERR_PROTOCOL,
+	XFERS_INFLIGHT,
 	SCMI_DEBUG_COUNTERS_LAST
 };
 
@@ -314,6 +315,12 @@ static inline void scmi_inc_count(atomic_t *arr, int stat)
 		atomic_inc(&arr[stat]);
 }
 
+static inline void scmi_dec_count(atomic_t *arr, int stat)
+{
+	if (IS_ENABLED(CONFIG_ARM_SCMI_DEBUG_COUNTERS))
+		atomic_dec(&arr[stat]);
+}
+
 enum scmi_bad_msg {
 	MSG_UNEXPECTED = -1,
 	MSG_INVALID = -2,
@@ -498,4 +505,5 @@ static struct platform_driver __drv = {					       \
 void scmi_notification_instance_data_set(const struct scmi_handle *handle,
 					 void *priv);
 void *scmi_notification_instance_data_get(const struct scmi_handle *handle);
+int scmi_inflight_count(const struct scmi_handle *handle);
 #endif /* _SCMI_COMMON_H */

drivers/firmware/arm_scmi/driver.c

@@ -190,6 +190,7 @@ struct scmi_info {
 };
 
 #define handle_to_scmi_info(h)	container_of(h, struct scmi_info, handle)
+#define tx_minfo_to_scmi_info(h) container_of(h, struct scmi_info, tx_minfo)
 #define bus_nb_to_scmi_info(nb)	container_of(nb, struct scmi_info, bus_nb)
 #define req_nb_to_scmi_info(nb)	container_of(nb, struct scmi_info, dev_req_nb)
 
@@ -603,9 +604,14 @@ static inline void
 scmi_xfer_inflight_register_unlocked(struct scmi_xfer *xfer,
 				     struct scmi_xfers_info *minfo)
 {
+	/* In this context minfo will be tx_minfo due to the xfer pending */
+	struct scmi_info *info = tx_minfo_to_scmi_info(minfo);
+
 	/* Set in-flight */
 	set_bit(xfer->hdr.seq, minfo->xfer_alloc_table);
 	hash_add(minfo->pending_xfers, &xfer->node, xfer->hdr.seq);
+	scmi_inc_count(info->dbg->counters, XFERS_INFLIGHT);
+
 	xfer->pending = true;
 }
 
@@ -807,9 +813,13 @@ __scmi_xfer_put(struct scmi_xfers_info *minfo, struct scmi_xfer *xfer)
 	spin_lock_irqsave(&minfo->xfer_lock, flags);
 	if (refcount_dec_and_test(&xfer->users)) {
 		if (xfer->pending) {
+			struct scmi_info *info = tx_minfo_to_scmi_info(minfo);
+
 			scmi_xfer_token_clear(minfo, xfer);
 			hash_del(&xfer->node);
 			xfer->pending = false;
+
+			scmi_dec_count(info->dbg->counters, XFERS_INFLIGHT);
 		}
 		hlist_add_head(&xfer->node, &minfo->free_xfers);
 	}
@@ -1433,7 +1443,8 @@ static int do_xfer(const struct scmi_protocol_handle *ph,
 
 	trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id,
 			      xfer->hdr.protocol_id, xfer->hdr.seq,
-			      xfer->hdr.poll_completion);
+			      xfer->hdr.poll_completion,
+			      scmi_inflight_count(&info->handle));
 
 	/* Clear any stale status */
 	xfer->hdr.status = SCMI_SUCCESS;
@@ -1469,7 +1480,8 @@ static int do_xfer(const struct scmi_protocol_handle *ph,
 		info->desc->ops->mark_txdone(cinfo, ret, xfer);
 
 	trace_scmi_xfer_end(xfer->transfer_id, xfer->hdr.id,
-			    xfer->hdr.protocol_id, xfer->hdr.seq, ret);
+			    xfer->hdr.protocol_id, xfer->hdr.seq, ret,
+			    scmi_inflight_count(&info->handle));
 
 	return ret;
 }
@@ -2912,6 +2924,7 @@ static const char * const dbg_counter_strs[] = {
 	"err_msg_invalid",
 	"err_msg_nomem",
 	"err_protocol",
+	"xfers_inflight",
 };
 
 static ssize_t reset_all_on_write(struct file *filp, const char __user *buf,
@@ -3405,6 +3418,17 @@ static struct dentry *scmi_debugfs_init(void)
 	return d;
 }
 
+int scmi_inflight_count(const struct scmi_handle *handle)
+{
+	if (IS_ENABLED(CONFIG_ARM_SCMI_DEBUG_COUNTERS)) {
+		struct scmi_info *info = handle_to_scmi_info(handle);
+
+		return atomic_read(&info->dbg->counters[XFERS_INFLIGHT]);
+	} else {
+		return 0;
+	}
+}
+
 static int __init scmi_driver_init(void)
 {
 	scmi_quirks_initialize();

drivers/firmware/arm_scmi/notify.c

@@ -318,6 +318,9 @@ struct scmi_registered_events_desc {
  *	    customized event report
  * @num_sources: The number of possible sources for this event as stated at
  *		 events' registration time
+ * @not_supported_by_platform: A flag to indicate that not even one source was
+ *			       found to be supported by the platform for this
+ *			       event
  * @sources: A reference to a dynamically allocated array used to refcount the
  *	     events' enable requests for all the existing sources
  * @sources_mtx: A mutex to serialize the access to @sources
@@ -334,6 +337,7 @@ struct scmi_registered_event {
 	const struct scmi_event	*evt;
 	void		*report;
 	u32		num_sources;
+	bool		not_supported_by_platform;
 	refcount_t	*sources;
 	/* locking to serialize the access to sources */
 	struct mutex	sources_mtx;
@@ -811,10 +815,19 @@ int scmi_register_protocol_events(const struct scmi_handle *handle, u8 proto_id,
 		if (!r_evt->report)
 			return -ENOMEM;
 
-		for (id = 0; id < r_evt->num_sources; id++)
-			if (ee->ops->is_notify_supported &&
-			    !ee->ops->is_notify_supported(ph, r_evt->evt->id, id))
-				refcount_set(&r_evt->sources[id], NOTIF_UNSUPP);
+		if (ee->ops->is_notify_supported) {
+			int supported = 0;
+
+			for (id = 0; id < r_evt->num_sources; id++) {
+				if (!ee->ops->is_notify_supported(ph, r_evt->evt->id, id))
+					refcount_set(&r_evt->sources[id], NOTIF_UNSUPP);
+				else
+					supported++;
+			}
+
+			/* Not even one source has been found to be supported */
+			r_evt->not_supported_by_platform = !supported;
+		}
 
 		pd->registered_events[i] = r_evt;
 		/* Ensure events are updated */
@@ -936,6 +949,11 @@ static inline int scmi_bind_event_handler(struct scmi_notify_instance *ni,
 	 * of protocol instance.
 	 */
 	hash_del(&hndl->hash);
+
+	/* Bailout if event is not supported at all */
+	if (r_evt->not_supported_by_platform)
+		return -EOPNOTSUPP;
+
 	/*
 	 * Acquire protocols only for NON pending handlers, so as NOT to trigger
 	 * protocol initialization when a notifier is registered against a still
@@ -1060,6 +1078,9 @@ __scmi_event_handler_get_ops(struct scmi_notify_instance *ni,
 	r_evt = SCMI_GET_REVT(ni, KEY_XTRACT_PROTO_ID(evt_key),
 			      KEY_XTRACT_EVT_ID(evt_key));
 
+	if (r_evt && r_evt->not_supported_by_platform)
+		return ERR_PTR(-EOPNOTSUPP);
+
 	mutex_lock(&ni->pending_mtx);
 	/* Search registered events at first ... if possible at all */
 	if (r_evt) {
@@ -1087,7 +1108,7 @@ __scmi_event_handler_get_ops(struct scmi_notify_instance *ni,
 				hndl->key);
 			/* this hndl can be only a pending one */
 			scmi_put_handler_unlocked(ni, hndl);
-			hndl = NULL;
+			hndl = ERR_PTR(-EINVAL);
 		}
 	}
 	mutex_unlock(&ni->pending_mtx);
@@ -1370,8 +1391,8 @@ static int scmi_notifier_register(const struct scmi_handle *handle,
 	evt_key = MAKE_HASH_KEY(proto_id, evt_id,
 				src_id ? *src_id : SRC_ID_MASK);
 	hndl = scmi_get_or_create_handler(ni, evt_key);
-	if (!hndl)
-		return -EINVAL;
+	if (IS_ERR(hndl))
+		return PTR_ERR(hndl);
 
 	blocking_notifier_chain_register(&hndl->chain, nb);
 
@@ -1416,8 +1437,8 @@ static int scmi_notifier_unregister(const struct scmi_handle *handle,
 	evt_key = MAKE_HASH_KEY(proto_id, evt_id,
 				src_id ? *src_id : SRC_ID_MASK);
 	hndl = scmi_get_handler(ni, evt_key);
-	if (!hndl)
-		return -EINVAL;
+	if (IS_ERR(hndl))
+		return PTR_ERR(hndl);
 
 	/*
 	 * Note that this chain unregistration call is safe on its own

drivers/firmware/arm_scmi/perf.c

@@ -892,7 +892,7 @@ static int scmi_dvfs_device_opps_add(const struct scmi_protocol_handle *ph,
 			freq = dom->opp[idx].indicative_freq * dom->mult_factor;
 
 		/* All OPPs above the sustained frequency are treated as turbo */
-		data.turbo = freq > dom->sustained_freq_khz * 1000;
+		data.turbo = freq > dom->sustained_freq_khz * 1000UL;
 
 		data.level = dom->opp[idx].perf;
 		data.freq = freq;

drivers/firmware/arm_scmi/raw_mode.c

@@ -475,7 +475,8 @@ static void scmi_xfer_raw_worker(struct work_struct *work)
 			raw->desc->ops->mark_txdone(rw->cinfo, ret, xfer);
 
 		trace_scmi_xfer_end(xfer->transfer_id, xfer->hdr.id,
-				    xfer->hdr.protocol_id, xfer->hdr.seq, ret);
+				    xfer->hdr.protocol_id, xfer->hdr.seq,
+				    ret, scmi_inflight_count(raw->handle));
 
 		/* Wait also for an async delayed response if needed */
 		if (!ret && xfer->async_done) {
@@ -642,7 +643,8 @@ static int scmi_do_xfer_raw_start(struct scmi_raw_mode_info *raw,
 
 	trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id,
 			      xfer->hdr.protocol_id, xfer->hdr.seq,
-			      xfer->hdr.poll_completion);
+			      xfer->hdr.poll_completion,
+			      scmi_inflight_count(raw->handle));
 
 	ret = raw->desc->ops->send_message(rw->cinfo, xfer);
 	if (ret) {

drivers/firmware/arm_scmi/scmi_power_control.c

@@ -46,6 +46,7 @@
 #include <linux/math.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/pm.h>
 #include <linux/printk.h>
 #include <linux/reboot.h>
 #include <linux/scmi_protocol.h>
@@ -324,12 +325,7 @@ static int scmi_userspace_notifier(struct notifier_block *nb,
 
 static void scmi_suspend_work_func(struct work_struct *work)
 {
-	struct scmi_syspower_conf *sc =
-		container_of(work, struct scmi_syspower_conf, suspend_work);
-
 	pm_suspend(PM_SUSPEND_MEM);
-
-	sc->state = SCMI_SYSPOWER_IDLE;
 }
 
 static int scmi_syspower_probe(struct scmi_device *sdev)
@@ -354,6 +350,7 @@ static int scmi_syspower_probe(struct scmi_device *sdev)
 	sc->required_transition = SCMI_SYSTEM_MAX;
 	sc->userspace_nb.notifier_call = &scmi_userspace_notifier;
 	sc->dev = &sdev->dev;
+	dev_set_drvdata(&sdev->dev, sc);
 
 	INIT_WORK(&sc->suspend_work, scmi_suspend_work_func);
 
@@ -363,6 +360,18 @@ static int scmi_syspower_probe(struct scmi_device *sdev)
 						       NULL, &sc->userspace_nb);
 }
 
+static int scmi_system_power_resume(struct device *dev)
+{
+	struct scmi_syspower_conf *sc = dev_get_drvdata(dev);
+
+	sc->state = SCMI_SYSPOWER_IDLE;
+	return 0;
+}
+
+static const struct dev_pm_ops scmi_system_power_pmops = {
+	SYSTEM_SLEEP_PM_OPS(NULL, scmi_system_power_resume)
+};
+
 static const struct scmi_device_id scmi_id_table[] = {
 	{ SCMI_PROTOCOL_SYSTEM, "syspower" },
 	{ },
@@ -370,6 +379,9 @@ static const struct scmi_device_id scmi_id_table[] = {
 MODULE_DEVICE_TABLE(scmi, scmi_id_table);
 
 static struct scmi_driver scmi_system_power_driver = {
+	.driver	= {
+		.pm = pm_sleep_ptr(&scmi_system_power_pmops),
+	},
 	.name = "scmi-system-power",
 	.probe = scmi_syspower_probe,
 	.id_table = scmi_id_table,

include/trace/events/scmi.h

@@ -36,8 +36,8 @@ TRACE_EVENT(scmi_fc_call,
 
 TRACE_EVENT(scmi_xfer_begin,
 	TP_PROTO(int transfer_id, u8 msg_id, u8 protocol_id, u16 seq,
-		 bool poll),
-	TP_ARGS(transfer_id, msg_id, protocol_id, seq, poll),
+		 bool poll, int inflight),
+	TP_ARGS(transfer_id, msg_id, protocol_id, seq, poll, inflight),
 
 	TP_STRUCT__entry(
 		__field(int, transfer_id)
@@ -45,6 +45,7 @@ TRACE_EVENT(scmi_xfer_begin,
 		__field(u8, protocol_id)
 		__field(u16, seq)
 		__field(bool, poll)
+		__field(int, inflight)
 	),
 
 	TP_fast_assign(
@@ -53,11 +54,12 @@ TRACE_EVENT(scmi_xfer_begin,
 		__entry->protocol_id = protocol_id;
 		__entry->seq = seq;
 		__entry->poll = poll;
+		__entry->inflight = inflight;
 	),
 
-	TP_printk("pt=%02X msg_id=%02X seq=%04X transfer_id=%X poll=%u",
-		__entry->protocol_id, __entry->msg_id, __entry->seq,
-		__entry->transfer_id, __entry->poll)
+	TP_printk("pt=%02X msg_id=%02X seq=%04X transfer_id=%X poll=%u inflight=%d",
+		  __entry->protocol_id, __entry->msg_id, __entry->seq,
+		  __entry->transfer_id, __entry->poll, __entry->inflight)
 );
 
 TRACE_EVENT(scmi_xfer_response_wait,
@@ -90,8 +92,8 @@ TRACE_EVENT(scmi_xfer_response_wait,
 
 TRACE_EVENT(scmi_xfer_end,
 	TP_PROTO(int transfer_id, u8 msg_id, u8 protocol_id, u16 seq,
-		 int status),
-	TP_ARGS(transfer_id, msg_id, protocol_id, seq, status),
+		 int status, int inflight),
+	TP_ARGS(transfer_id, msg_id, protocol_id, seq, status, inflight),
 
 	TP_STRUCT__entry(
 		__field(int, transfer_id)
@@ -99,6 +101,7 @@ TRACE_EVENT(scmi_xfer_end,
 		__field(u8, protocol_id)
 		__field(u16, seq)
 		__field(int, status)
+		__field(int, inflight)
 	),
 
 	TP_fast_assign(
@@ -107,11 +110,12 @@ TRACE_EVENT(scmi_xfer_end,
 		__entry->protocol_id = protocol_id;
 		__entry->seq = seq;
 		__entry->status = status;
+		__entry->inflight = inflight;
 	),
 
-	TP_printk("pt=%02X msg_id=%02X seq=%04X transfer_id=%X s=%d",
-		__entry->protocol_id, __entry->msg_id, __entry->seq,
-		__entry->transfer_id, __entry->status)
+	TP_printk("pt=%02X msg_id=%02X seq=%04X transfer_id=%X s=%d inflight=%d",
+		  __entry->protocol_id, __entry->msg_id, __entry->seq,
+		  __entry->transfer_id, __entry->status, __entry->inflight)
 );
 
 TRACE_EVENT(scmi_rx_done,