Merge tag 'scmi-updates-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into soc/drivers

Arm SCMI updates for v6.8

Few minor updates:

1. Addition of protocol versioning checks to warn if the firmware version
   is newer or greater than the version supported by the kernel driver

2. Increment of the maximum OPP count in the perf protocol from 16 to 32
   as needed by a few recent/future qualcomm platforms

3. Optimisation of set performance operations by returning error
   immediately and avoiding to send the command to the platform(which
   would return error eventually) if the domain doesn't support perf
   operations. Similarly, the fastchannel handling is also optimised by
   avoiding to initialise the corresponding set operations fastchannels.

4. Extension of extended names helper to accomodate recently added new
   flags parameter to be able to properly configure the command used to
   query the extended name of a resource.

* tag 'scmi-updates-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  firmware: arm_scmi: Add protocol versioning checks
  firmware: arm_scmi: Increase the maximum opp count in the perf protocol
  firmware: arm_scmi: Fix NULL pointer dereference during fastchannel init
  firmware: arm_scmi: Add optional flags to extended names helper
  firmware: arm_scmi: Populate fastchannel info only if set operations are allowed
  firmware: arm_scmi: Check beforehand if the perf domain set operations are allowed

Link: https://lore.kernel.org/r/20231213115953.3578115-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Author: arndb

drivers/firmware/arm_scmi/base.c

@@ -13,6 +13,9 @@
 #include "common.h"
 #include "notify.h"
 
+/* Updated only after ALL the mandatory features for that version are merged */
+#define SCMI_PROTOCOL_SUPPORTED_VERSION		0x20000
+
 #define SCMI_BASE_NUM_SOURCES		1
 #define SCMI_BASE_MAX_CMD_ERR_COUNT	1024
 
@@ -385,7 +388,7 @@ static int scmi_base_protocol_init(const struct scmi_protocol_handle *ph)
 
 	rev->major_ver = PROTOCOL_REV_MAJOR(version),
 	rev->minor_ver = PROTOCOL_REV_MINOR(version);
-	ph->set_priv(ph, rev);
+	ph->set_priv(ph, rev, version);
 
 	ret = scmi_base_attributes_get(ph);
 	if (ret)
@@ -423,6 +426,7 @@ static const struct scmi_protocol scmi_base = {
 	.instance_init = &scmi_base_protocol_init,
 	.ops = NULL,
 	.events = &base_protocol_events,
+	.supported_version = SCMI_PROTOCOL_SUPPORTED_VERSION,
 };
 
 DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(base, scmi_base)

drivers/firmware/arm_scmi/clock.c

@@ -12,6 +12,9 @@
 #include "protocols.h"
 #include "notify.h"
 
+/* Updated only after ALL the mandatory features for that version are merged */
+#define SCMI_PROTOCOL_SUPPORTED_VERSION		0x20001
+
 enum scmi_clock_protocol_cmd {
 	CLOCK_ATTRIBUTES = 0x3,
 	CLOCK_DESCRIBE_RATES = 0x4,
@@ -318,7 +321,7 @@ static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
 	if (!ret && PROTOCOL_REV_MAJOR(version) >= 0x2) {
 		if (SUPPORTS_EXTENDED_NAMES(attributes))
 			ph->hops->extended_name_get(ph, CLOCK_NAME_GET, clk_id,
-						    clk->name,
+						    NULL, clk->name,
 						    SCMI_MAX_STR_SIZE);
 
 		if (SUPPORTS_RATE_CHANGED_NOTIF(attributes))
@@ -961,7 +964,7 @@ static int scmi_clock_protocol_init(const struct scmi_protocol_handle *ph)
 	}
 
 	cinfo->version = version;
-	return ph->set_priv(ph, cinfo);
+	return ph->set_priv(ph, cinfo, version);
 }
 
 static const struct scmi_protocol scmi_clock = {
@@ -970,6 +973,7 @@ static const struct scmi_protocol scmi_clock = {
 	.instance_init = &scmi_clock_protocol_init,
 	.ops = &clk_proto_ops,
 	.events = &clk_protocol_events,
+	.supported_version = SCMI_PROTOCOL_SUPPORTED_VERSION,
 };
 
 DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(clock, scmi_clock)

drivers/firmware/arm_scmi/driver.c

@@ -85,6 +85,7 @@ struct scmi_xfers_info {
  * @gid: A reference for per-protocol devres management.
  * @users: A refcount to track effective users of this protocol.
  * @priv: Reference for optional protocol private data.
+ * @version: Protocol version supported by the platform as detected at runtime.
  * @ph: An embedded protocol handle that will be passed down to protocol
  *	initialization code to identify this instance.
  *
@@ -97,6 +98,7 @@ struct scmi_protocol_instance {
 	void				*gid;
 	refcount_t			users;
 	void				*priv;
+	unsigned int			version;
 	struct scmi_protocol_handle	ph;
 };
 
@@ -1392,15 +1394,17 @@ static int version_get(const struct scmi_protocol_handle *ph, u32 *version)
  *
  * @ph: A reference to the protocol handle.
  * @priv: The private data to set.
+ * @version: The detected protocol version for the core to register.
  *
  * Return: 0 on Success
  */
 static int scmi_set_protocol_priv(const struct scmi_protocol_handle *ph,
-				  void *priv)
+				  void *priv, u32 version)
 {
 	struct scmi_protocol_instance *pi = ph_to_pi(ph);
 
 	pi->priv = priv;
+	pi->version = version;
 
 	return 0;
 }
@@ -1438,26 +1442,30 @@ struct scmi_msg_resp_domain_name_get {
  * @ph: A protocol handle reference.
  * @cmd_id: The specific command ID to use.
  * @res_id: The specific resource ID to use.
+ * @flags: A pointer to specific flags to use, if any.
  * @name: A pointer to the preallocated area where the retrieved name will be
  *	  stored as a NULL terminated string.
  * @len: The len in bytes of the @name char array.
  *
  * Return: 0 on Succcess
  */
 static int scmi_common_extended_name_get(const struct scmi_protocol_handle *ph,
-					 u8 cmd_id, u32 res_id, char *name,
-					 size_t len)
+					 u8 cmd_id, u32 res_id, u32 *flags,
+					 char *name, size_t len)
 {
 	int ret;
+	size_t txlen;
 	struct scmi_xfer *t;
 	struct scmi_msg_resp_domain_name_get *resp;
 
-	ret = ph->xops->xfer_get_init(ph, cmd_id, sizeof(res_id),
-				      sizeof(*resp), &t);
+	txlen = !flags ? sizeof(res_id) : sizeof(res_id) + sizeof(*flags);
+	ret = ph->xops->xfer_get_init(ph, cmd_id, txlen, sizeof(*resp), &t);
 	if (ret)
 		goto out;
 
 	put_unaligned_le32(res_id, t->tx.buf);
+	if (flags)
+		put_unaligned_le32(*flags, t->tx.buf + sizeof(res_id));
 	resp = t->rx.buf;
 
 	ret = ph->xops->do_xfer(ph, t);
@@ -1845,6 +1853,12 @@ 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)
+		dev_warn(handle->dev,
+			 "Detected UNSUPPORTED higher version 0x%X for protocol 0x%X."
+			 "Backward compatibility is NOT assured.\n",
+			 pi->version, pi->proto->id);
+
 	return pi;
 
 clean:

drivers/firmware/arm_scmi/perf.c

@@ -24,7 +24,10 @@
 #include "protocols.h"
 #include "notify.h"
 
-#define MAX_OPPS		16
+/* Updated only after ALL the mandatory features for that version are merged */
+#define SCMI_PROTOCOL_SUPPORTED_VERSION		0x40000
+
+#define MAX_OPPS		32
 
 enum scmi_performance_protocol_cmd {
 	PERF_DOMAIN_ATTRIBUTES = 0x3,
@@ -288,7 +291,7 @@ scmi_perf_domain_attributes_get(const struct scmi_protocol_handle *ph,
 	if (!ret && PROTOCOL_REV_MAJOR(version) >= 0x3 &&
 	    SUPPORTS_EXTENDED_NAMES(flags))
 		ph->hops->extended_name_get(ph, PERF_DOMAIN_NAME_GET,
-					    dom_info->id, dom_info->info.name,
+					    dom_info->id, NULL, dom_info->info.name,
 					    SCMI_MAX_STR_SIZE);
 
 	if (dom_info->level_indexing_mode) {
@@ -504,6 +507,9 @@ static int scmi_perf_limits_set(const struct scmi_protocol_handle *ph,
 	if (IS_ERR(dom))
 		return PTR_ERR(dom);
 
+	if (!dom->set_limits)
+		return -EOPNOTSUPP;
+
 	if (PROTOCOL_REV_MAJOR(pi->version) >= 0x3 && !max_perf && !min_perf)
 		return -EINVAL;
 
@@ -654,6 +660,9 @@ static int scmi_perf_level_set(const struct scmi_protocol_handle *ph,
 	if (IS_ERR(dom))
 		return PTR_ERR(dom);
 
+	if (!dom->info.set_perf)
+		return -EOPNOTSUPP;
+
 	if (dom->level_indexing_mode) {
 		struct scmi_opp *opp;
 
@@ -753,7 +762,7 @@ static int scmi_perf_level_limits_notify(const struct scmi_protocol_handle *ph,
 }
 
 static void scmi_perf_domain_init_fc(const struct scmi_protocol_handle *ph,
-				     u32 domain, struct scmi_fc_info **p_fc)
+				     struct perf_dom_info *dom)
 {
 	struct scmi_fc_info *fc;
 
@@ -762,24 +771,26 @@ static void scmi_perf_domain_init_fc(const struct scmi_protocol_handle *ph,
 		return;
 
 	ph->hops->fastchannel_init(ph, PERF_DESCRIBE_FASTCHANNEL,
-				   PERF_LEVEL_SET, 4, domain,
-				   &fc[PERF_FC_LEVEL].set_addr,
-				   &fc[PERF_FC_LEVEL].set_db);
-
-	ph->hops->fastchannel_init(ph, PERF_DESCRIBE_FASTCHANNEL,
-				   PERF_LEVEL_GET, 4, domain,
+				   PERF_LEVEL_GET, 4, dom->id,
 				   &fc[PERF_FC_LEVEL].get_addr, NULL);
 
 	ph->hops->fastchannel_init(ph, PERF_DESCRIBE_FASTCHANNEL,
-				   PERF_LIMITS_SET, 8, domain,
-				   &fc[PERF_FC_LIMIT].set_addr,
-				   &fc[PERF_FC_LIMIT].set_db);
-
-	ph->hops->fastchannel_init(ph, PERF_DESCRIBE_FASTCHANNEL,
-				   PERF_LIMITS_GET, 8, domain,
+				   PERF_LIMITS_GET, 8, dom->id,
 				   &fc[PERF_FC_LIMIT].get_addr, NULL);
 
-	*p_fc = fc;
+	if (dom->info.set_perf)
+		ph->hops->fastchannel_init(ph, PERF_DESCRIBE_FASTCHANNEL,
+					   PERF_LEVEL_SET, 4, dom->id,
+					   &fc[PERF_FC_LEVEL].set_addr,
+					   &fc[PERF_FC_LEVEL].set_db);
+
+	if (dom->set_limits)
+		ph->hops->fastchannel_init(ph, PERF_DESCRIBE_FASTCHANNEL,
+					   PERF_LIMITS_SET, 8, dom->id,
+					   &fc[PERF_FC_LIMIT].set_addr,
+					   &fc[PERF_FC_LIMIT].set_db);
+
+	dom->fc_info = fc;
 }
 
 static int scmi_dvfs_device_opps_add(const struct scmi_protocol_handle *ph,
@@ -1089,14 +1100,14 @@ static int scmi_perf_protocol_init(const struct scmi_protocol_handle *ph)
 		scmi_perf_describe_levels_get(ph, dom, version);
 
 		if (dom->perf_fastchannels)
-			scmi_perf_domain_init_fc(ph, dom->id, &dom->fc_info);
+			scmi_perf_domain_init_fc(ph, dom);
 	}
 
 	ret = devm_add_action_or_reset(ph->dev, scmi_perf_xa_destroy, pinfo);
 	if (ret)
 		return ret;
 
-	return ph->set_priv(ph, pinfo);
+	return ph->set_priv(ph, pinfo, version);
 }
 
 static const struct scmi_protocol scmi_perf = {
@@ -1105,6 +1116,7 @@ static const struct scmi_protocol scmi_perf = {
 	.instance_init = &scmi_perf_protocol_init,
 	.ops = &perf_proto_ops,
 	.events = &perf_protocol_events,
+	.supported_version = SCMI_PROTOCOL_SUPPORTED_VERSION,
 };
 
 DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(perf, scmi_perf)

drivers/firmware/arm_scmi/power.c

@@ -13,6 +13,9 @@
 #include "protocols.h"
 #include "notify.h"
 
+/* Updated only after ALL the mandatory features for that version are merged */
+#define SCMI_PROTOCOL_SUPPORTED_VERSION		0x30000
+
 enum scmi_power_protocol_cmd {
 	POWER_DOMAIN_ATTRIBUTES = 0x3,
 	POWER_STATE_SET = 0x4,
@@ -133,7 +136,7 @@ scmi_power_domain_attributes_get(const struct scmi_protocol_handle *ph,
 	if (!ret && PROTOCOL_REV_MAJOR(version) >= 0x3 &&
 	    SUPPORTS_EXTENDED_NAMES(flags)) {
 		ph->hops->extended_name_get(ph, POWER_DOMAIN_NAME_GET,
-					    domain, dom_info->name,
+					    domain, NULL, dom_info->name,
 					    SCMI_MAX_STR_SIZE);
 	}
 
@@ -328,7 +331,7 @@ static int scmi_power_protocol_init(const struct scmi_protocol_handle *ph)
 
 	pinfo->version = version;
 
-	return ph->set_priv(ph, pinfo);
+	return ph->set_priv(ph, pinfo, version);
 }
 
 static const struct scmi_protocol scmi_power = {
@@ -337,6 +340,7 @@ static const struct scmi_protocol scmi_power = {
 	.instance_init = &scmi_power_protocol_init,
 	.ops = &power_proto_ops,
 	.events = &power_protocol_events,
+	.supported_version = SCMI_PROTOCOL_SUPPORTED_VERSION,
 };
 
 DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(power, scmi_power)

drivers/firmware/arm_scmi/powercap.c

@@ -17,6 +17,9 @@
 #include "protocols.h"
 #include "notify.h"
 
+/* Updated only after ALL the mandatory features for that version are merged */
+#define SCMI_PROTOCOL_SUPPORTED_VERSION		0x20000
+
 enum scmi_powercap_protocol_cmd {
 	POWERCAP_DOMAIN_ATTRIBUTES = 0x3,
 	POWERCAP_CAP_GET = 0x4,
@@ -270,7 +273,7 @@ scmi_powercap_domain_attributes_get(const struct scmi_protocol_handle *ph,
 	 */
 	if (!ret && SUPPORTS_EXTENDED_NAMES(flags))
 		ph->hops->extended_name_get(ph, POWERCAP_DOMAIN_NAME_GET,
-					    domain, dom_info->name,
+					    domain, NULL, dom_info->name,
 					    SCMI_MAX_STR_SIZE);
 
 	return ret;
@@ -975,7 +978,7 @@ scmi_powercap_protocol_init(const struct scmi_protocol_handle *ph)
 	}
 
 	pinfo->version = version;
-	return ph->set_priv(ph, pinfo);
+	return ph->set_priv(ph, pinfo, version);
 }
 
 static const struct scmi_protocol scmi_powercap = {
@@ -984,6 +987,7 @@ static const struct scmi_protocol scmi_powercap = {
 	.instance_init = &scmi_powercap_protocol_init,
 	.ops = &powercap_proto_ops,
 	.events = &powercap_protocol_events,
+	.supported_version = SCMI_PROTOCOL_SUPPORTED_VERSION,
 };
 
 DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(powercap, scmi_powercap)

drivers/firmware/arm_scmi/protocols.h

@@ -174,7 +174,8 @@ struct scmi_protocol_handle {
 	struct device *dev;
 	const struct scmi_xfer_ops *xops;
 	const struct scmi_proto_helpers_ops *hops;
-	int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv);
+	int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv,
+			u32 version);
 	void *(*get_priv)(const struct scmi_protocol_handle *ph);
 };
 
@@ -256,7 +257,8 @@ struct scmi_fc_info {
  */
 struct scmi_proto_helpers_ops {
 	int (*extended_name_get)(const struct scmi_protocol_handle *ph,
-				 u8 cmd_id, u32 res_id, char *name, size_t len);
+				 u8 cmd_id, u32 res_id, u32 *flags, char *name,
+				 size_t len);
 	void *(*iter_response_init)(const struct scmi_protocol_handle *ph,
 				    struct scmi_iterator_ops *ops,
 				    unsigned int max_resources, u8 msg_id,
@@ -310,6 +312,10 @@ typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *);
  * @ops: Optional reference to the operations provided by the protocol and
  *	 exposed in scmi_protocol.h.
  * @events: An optional reference to the events supported by this protocol.
+ * @supported_version: The highest version currently supported for this
+ *		       protocol by the agent. Each protocol implementation
+ *		       in the agent is supposed to downgrade to match the
+ *		       protocol version supported by the platform.
  */
 struct scmi_protocol {
 	const u8				id;
@@ -318,6 +324,7 @@ struct scmi_protocol {
 	const scmi_prot_init_ph_fn_t		instance_deinit;
 	const void				*ops;
 	const struct scmi_protocol_events	*events;
+	unsigned int				supported_version;
 };
 
 #define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto)	\