firmware: xilinx: Add debugfs support for PM_GET_NODE_STATUS

Add new debug interface to support PM_GET_NODE_STATUS to get the node
information like requirements and usage.

The debugfs firmware driver interface is only meant for testing and
debugging EEMI APIs. Hence, it is by-default disabled in production
systems.

Signed-off-by: Madhav Bhatt <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Michal Simek <[e-mail]>

drivers/firmware/xilinx/zynqmp-debug.c

···
  * Xilinx Zynq MPSoC Firmware layer for debugfs APIs
  *
  *  Copyright (C) 2014-2018 Xilinx, Inc.
+ *  Copyright (C) 2022 - 2025 Advanced Micro Devices, Inc.
  *
  *  Michal Simek <[e-mail]>
  *  Davorin Mista <[e-mail]>
···
 	PM_API(PM_RELEASE_NODE),
 	PM_API(PM_SET_REQUIREMENT),
 	PM_API(PM_GET_API_VERSION),
+	PM_API(PM_GET_NODE_STATUS),
 	PM_API(PM_REGISTER_NOTIFIER),
 	PM_API(PM_RESET_ASSERT),
 	PM_API(PM_RESET_GET_STATUS),
···
 						pm_api_arg[2] : 0,
 						pm_api_arg[3] ? pm_api_arg[3] :
 						ZYNQMP_PM_REQUEST_ACK_BLOCKING);
+		break;
+	case PM_GET_NODE_STATUS:
+		ret = zynqmp_pm_get_node_status(pm_api_arg[0],
+						&pm_api_ret[0],
+						&pm_api_ret[1],
+						&pm_api_ret[2]);
+		if (!ret)
+			sprintf(debugfs_buf,
+				"GET_NODE_STATUS:\n\tNodeId: %llu\n\tStatus: %u\n\tRequirements: %u\n\tUsage: %u\n",
+				pm_api_arg[0], pm_api_ret[0],
+				pm_api_ret[1], pm_api_ret[2]);
 		break;
 	case PM_REGISTER_NOTIFIER:
 		ret = zynqmp_pm_register_notifier(pm_api_arg[0],

drivers/firmware/xilinx/zynqmp.c

···
  * Xilinx Zynq MPSoC Firmware layer
  *
  *  Copyright (C) 2014-2022 Xilinx, Inc.
- *  Copyright (C) 2022 - 2024, Advanced Micro Devices, Inc.
+ *  Copyright (C) 2022 - 2025 Advanced Micro Devices, Inc.
  *
  *  Michal Simek <[e-mail]>
  *  Davorin Mista <[e-mail]>
···
 				   (u32)tcm_mode);
 }
 EXPORT_SYMBOL_GPL(zynqmp_pm_set_tcm_config);
+
+/**
+ * zynqmp_pm_get_node_status - PM call to request a node's current power state
+ * @node:		ID of the component or sub-system in question
+ * @status:		Current operating state of the requested node
+ * @requirements:	Current requirements asserted on the node,
+ *			used for slave nodes only.
+ * @usage:		Usage information, used for slave nodes only:
+ *			PM_USAGE_NO_MASTER	- No master is currently using
+ *						  the node
+ *			PM_USAGE_CURRENT_MASTER	- Only requesting master is
+ *						  currently using the node
+ *			PM_USAGE_OTHER_MASTER	- Only other masters are
+ *						  currently using the node
+ *			PM_USAGE_BOTH_MASTERS	- Both the current and at least
+ *						  one other master is currently
+ *						  using the node
+ *
+ * Return:		Returns status, either success or error+reason
+ */
+int zynqmp_pm_get_node_status(const u32 node, u32 *const status,
+			      u32 *const requirements, u32 *const usage)
+{
+	u32 ret_payload[PAYLOAD_ARG_CNT];
+	int ret;
+
+	if (!status || !requirements || !usage)
+		return -EINVAL;
+
+	ret = zynqmp_pm_invoke_fn(PM_GET_NODE_STATUS, ret_payload, 1, node);
+	if (ret_payload[0] == XST_PM_SUCCESS) {
+		*status = ret_payload[1];
+		*requirements = ret_payload[2];
+		*usage = ret_payload[3];
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(zynqmp_pm_get_node_status);
 
 /**
  * zynqmp_pm_force_pwrdwn - PM call to request for another PU or subsystem to

include/linux/firmware/xlnx-zynqmp.h

···
  * Xilinx Zynq MPSoC Firmware layer
  *
  *  Copyright (C) 2014-2021 Xilinx
- *  Copyright (C) 2022 - 2024, Advanced Micro Devices, Inc.
+ *  Copyright (C) 2022 - 2025 Advanced Micro Devices, Inc.
  *
  *  Michal Simek <[e-mail]>
  *  Davorin Mista <[e-mail]>
···
 enum pm_api_id {
 	PM_API_FEATURES = 0,
 	PM_GET_API_VERSION = 1,
+	PM_GET_NODE_STATUS = 3,
 	PM_REGISTER_NOTIFIER = 5,
 	PM_FORCE_POWERDOWN = 8,
 	PM_REQUEST_WAKEUP = 10,
···
 int zynqmp_pm_get_rpu_mode(u32 node_id, enum rpu_oper_mode *rpu_mode);
 int zynqmp_pm_set_rpu_mode(u32 node_id, enum rpu_oper_mode rpu_mode);
 int zynqmp_pm_set_tcm_config(u32 node_id, enum rpu_tcm_comb tcm_mode);
+int zynqmp_pm_get_node_status(const u32 node, u32 *const status,
+			      u32 *const requirements, u32 *const usage);
 int zynqmp_pm_set_sd_config(u32 node, enum pm_sd_config_type config, u32 value);
 int zynqmp_pm_set_gem_config(u32 node, enum pm_gem_config_type config,
 			     u32 value);
···
 }
 
 static inline int zynqmp_pm_set_tcm_config(u32 node_id, enum rpu_tcm_comb tcm_mode)
+{
+	return -ENODEV;
+}
+
+static inline int zynqmp_pm_get_node_status(const u32 node, u32 *const status,
+					    u32 *const requirements,
+					    u32 *const usage)
 {
 	return -ENODEV;
 }