[PATCH v5 4/4] drivers: firmware: xilinx: Add debugfs interface

[Jolly Shah]

Firmware-debug provides debugfs interface to all APIs.
Debugfs can be used to call firmware APIs with required
parameters.

Usage:
* Calling firmware API through debugfs:
  # echo "<api-name> <arg1> .. <argn>" > /sys/kernel/debug/zynqmp-firmware/pm

* Read output of last called firmware API:
  # cat /sys/kernel/debug/zynqmp-firmware/pm

Refer ug1200 for more information on these APIs:
  * https://www.xilinx.com/support/documentation/user_guides/ug1200-eemi-api.pdf

Below are supported debugfs APIs:
    * PM_REQUEST_SUSPEND
    * PM_SELF_SUSPEND
    * PM_FORCE_POWERDOWN
    * PM_ABORT_SUSPEND
    * PM_REQUEST_WAKEUP
    * PM_SET_WAKEUP_SOURCE
    * PM_SYSTEM_SHUTDOWN
    * PM_REQUEST_NODE
    * PM_RELEASE_NODE
    * PM_SET_REQUIREMENT
    * PM_SET_MAX_LATENCY
    * PM_GET_API_VERSION
    * PM_SET_CONFIGURATION
    * PM_GET_NODE_STATUS
    * PM_GET_OPERATING_CHARACTERISTIC
    * PM_REGISTER_NOTIFIER
    * PM_RESET_ASSERT
    * PM_RESET_GET_STATUS
    * PM_GET_CHIPID
    * PM_PINCTRL_GET_FUNCTION
    * PM_PINCTRL_SET_FUNCTION
    * PM_PINCTRL_CONFIG_PARAM_GET
    * PM_PINCTRL_CONFIG_PARAM_SET
    * PM_IOCTL
    * PM_CLOCK_ENABLE
    * PM_CLOCK_DISABLE
    * PM_CLOCK_GETSTATE
    * PM_CLOCK_SETDIVIDER
    * PM_CLOCK_GETDIVIDER
    * PM_CLOCK_SETRATE
    * PM_CLOCK_GETRATE
    * PM_CLOCK_SETPARENT
    * PM_CLOCK_GETPARENT
    * PM_QUERY_DATA

Signed-off-by: Jolly Shah <jollys@xxxxxxxxxx>
Signed-off-by: Rajan Vaja <rajanv@xxxxxxxxxx>
---
 drivers/firmware/xilinx/zynqmp/Kconfig             |   7 +
 drivers/firmware/xilinx/zynqmp/Makefile            |   1 +
 drivers/firmware/xilinx/zynqmp/firmware-debug.c    | 482 +++++++++++++++++++++
 drivers/firmware/xilinx/zynqmp/firmware.c          |   7 +-
 .../linux/firmware/xilinx/zynqmp/firmware-debug.h  |  22 +
 5 files changed, 518 insertions(+), 1 deletion(-)
 create mode 100644 drivers/firmware/xilinx/zynqmp/firmware-debug.c
 create mode 100644 include/linux/firmware/xilinx/zynqmp/firmware-debug.h

diff --git a/drivers/firmware/xilinx/zynqmp/Kconfig b/drivers/firmware/xilinx/zynqmp/Kconfig
index 5054b80..5c22aba 100644
--- a/drivers/firmware/xilinx/zynqmp/Kconfig
+++ b/drivers/firmware/xilinx/zynqmp/Kconfig
@@ -13,4 +13,11 @@ config ZYNQMP_FIRMWARE
 	  Say yes to enable ZynqMP firmware interface driver.
 	  In doubt, say N
 
+config ZYNQMP_FIRMWARE_DEBUG
+	bool "Enable Xilinx Zynq MPSoC firmware debug APIs"
+	depends on ZYNQMP_FIRMWARE && DEBUG_FS
+	help
+	  Say yes to enable ZynqMP firmware interface debug APIs.
+	  In doubt, say N
+
 endmenu
diff --git a/drivers/firmware/xilinx/zynqmp/Makefile b/drivers/firmware/xilinx/zynqmp/Makefile
index 6629781..02f0c9a 100644
--- a/drivers/firmware/xilinx/zynqmp/Makefile
+++ b/drivers/firmware/xilinx/zynqmp/Makefile
@@ -2,3 +2,4 @@
 # Makefile for Xilinx firmwares
 
 obj-$(CONFIG_ZYNQMP_FIRMWARE) += firmware.o firmware-ggs.o
+obj-$(CONFIG_ZYNQMP_FIRMWARE_DEBUG) += firmware-debug.o
diff --git a/drivers/firmware/xilinx/zynqmp/firmware-debug.c b/drivers/firmware/xilinx/zynqmp/firmware-debug.c
new file mode 100644
index 0000000..5dd0d90
--- /dev/null
+++ b/drivers/firmware/xilinx/zynqmp/firmware-debug.c
@@ -0,0 +1,482 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Xilinx Zynq MPSoC Firmware layer for debugfs APIs
+ *
+ *  Copyright (C) 2014-2018 Xilinx, Inc.
+ *
+ *  Michal Simek <michal.simek@xxxxxxxxxx>
+ *  Davorin Mista <davorin.mista@xxxxxxxxxx>
+ *  Jolly Shah <jollys@xxxxxxxxxx>
+ *  Rajan Vaja <rajanv@xxxxxxxxxx>
+ */
+
+#include <linux/compiler.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/firmware/xilinx/zynqmp/firmware.h>
+#include <linux/firmware/xilinx/zynqmp/firmware-debug.h>
+
+#define PM_API_NAME_LEN			50
+
+struct pm_api_info {
+	u32 api_id;
+	char api_name[PM_API_NAME_LEN];
+	char api_name_len;
+};
+
+static char debugfs_buf[PAGE_SIZE];
+
+#define PM_API(id)		 {id, #id, strlen(#id)}
+static struct pm_api_info pm_api_list[] = {
+	PM_API(PM_REQUEST_SUSPEND),
+	PM_API(PM_SELF_SUSPEND),
+	PM_API(PM_FORCE_POWERDOWN),
+	PM_API(PM_ABORT_SUSPEND),
+	PM_API(PM_REQUEST_WAKEUP),
+	PM_API(PM_SET_WAKEUP_SOURCE),
+	PM_API(PM_SYSTEM_SHUTDOWN),
+	PM_API(PM_REQUEST_NODE),
+	PM_API(PM_RELEASE_NODE),
+	PM_API(PM_SET_REQUIREMENT),
+	PM_API(PM_SET_MAX_LATENCY),
+	PM_API(PM_GET_API_VERSION),
+	PM_API(PM_SET_CONFIGURATION),
+	PM_API(PM_GET_NODE_STATUS),
+	PM_API(PM_GET_OPERATING_CHARACTERISTIC),
+	PM_API(PM_REGISTER_NOTIFIER),
+	PM_API(PM_RESET_ASSERT),
+	PM_API(PM_RESET_GET_STATUS),
+	PM_API(PM_GET_CHIPID),
+	PM_API(PM_PINCTRL_GET_FUNCTION),
+	PM_API(PM_PINCTRL_SET_FUNCTION),
+	PM_API(PM_PINCTRL_CONFIG_PARAM_GET),
+	PM_API(PM_PINCTRL_CONFIG_PARAM_SET),
+	PM_API(PM_IOCTL),
+	PM_API(PM_CLOCK_ENABLE),
+	PM_API(PM_CLOCK_DISABLE),
+	PM_API(PM_CLOCK_GETSTATE),
+	PM_API(PM_CLOCK_SETDIVIDER),
+	PM_API(PM_CLOCK_GETDIVIDER),
+	PM_API(PM_CLOCK_SETRATE),
+	PM_API(PM_CLOCK_GETRATE),
+	PM_API(PM_CLOCK_SETPARENT),
+	PM_API(PM_CLOCK_GETPARENT),
+	PM_API(PM_QUERY_DATA),
+};
+
+/**
+ * zynqmp_pm_self_suspend - PM call for master to suspend itself
+ * @node:	Node ID of the master or subsystem
+ * @latency:	Requested maximum wakeup latency (not supported)
+ * @state:	Requested state (not supported)
+ *
+ * Return:	Returns status, either success or error+reason
+ */
+static int zynqmp_pm_self_suspend(const u32 node, const u32 latency,
+				  const u32 state)
+{
+	return zynqmp_pm_invoke_fn(PM_SELF_SUSPEND, node, latency,
+				   state, 0, NULL);
+}
+
+/**
+ * zynqmp_pm_abort_suspend - PM call to announce that a prior suspend request
+ *				is to be aborted.
+ * @reason:	Reason for the abort
+ *
+ * Return:	Returns status, either success or error+reason
+ */
+static int zynqmp_pm_abort_suspend(const enum zynqmp_pm_abort_reason reason)
+{
+	return zynqmp_pm_invoke_fn(PM_ABORT_SUSPEND, reason, 0, 0, 0, NULL);
+}
+
+/**
+ * zynqmp_pm_register_notifier - Register the PU to be notified of PM events
+ * @node:	Node ID of the slave
+ * @event:	The event to be notified about
+ * @wake:	Wake up on event
+ * @enable:	Enable or disable the notifier
+ *
+ * Return:	Returns status, either success or error+reason
+ */
+static int zynqmp_pm_register_notifier(const u32 node, const u32 event,
+				       const u32 wake, const u32 enable)
+{
+	return zynqmp_pm_invoke_fn(PM_REGISTER_NOTIFIER, node, event,
+				   wake, enable, NULL);
+}
+
+/**
+ * zynqmp_pm_argument_value - Extract argument value from a PM-API request
+ * @arg:	Entered PM-API argument in string format
+ *
+ * Return:	Argument value in unsigned integer format on success
+ *		0 otherwise
+ */
+static u64 zynqmp_pm_argument_value(char *arg)
+{
+	u64 value;
+
+	if (!arg)
+		return 0;
+
+	if (!kstrtou64(arg, 0, &value))
+		return value;
+
+	return 0;
+}
+
+static int get_pm_api_id(char *pm_api_req, u32 *pm_id)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(pm_api_list) ; i++) {
+		if (!strncasecmp(pm_api_req, pm_api_list[i].api_name,
+				 pm_api_list[i].api_name_len)) {
+			*pm_id = pm_api_list[i].api_id;
+			break;
+		}
+	}
+
+	/* If no name was entered look for PM-API ID instead */
+	if (i == ARRAY_SIZE(pm_api_list) && kstrtouint(pm_api_req, 10, pm_id))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int process_api_request(u32 pm_id, u64 *pm_api_arg, u32 *pm_api_ret)
+{
+	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
+	u32 pm_api_version;
+	u64 rate;
+	int ret;
+
+	if (!eemi_ops)
+		return -ENXIO;
+
+	switch (pm_id) {
+	case PM_GET_API_VERSION:
+		ret = eemi_ops->get_api_version(&pm_api_version);
+		sprintf(debugfs_buf, "PM-API Version = %d.%d\n",
+			pm_api_version >> 16, pm_api_version & 0xffff);
+		break;
+	case PM_REQUEST_SUSPEND:
+		ret = eemi_ops->request_suspend(pm_api_arg[0],
+						pm_api_arg[1] ? pm_api_arg[1] :
+						ZYNQMP_PM_REQUEST_ACK_NO,
+						pm_api_arg[2] ? pm_api_arg[2] :
+						ZYNQMP_PM_MAX_LATENCY, 0);
+		break;
+	case PM_SELF_SUSPEND:
+		ret = zynqmp_pm_self_suspend(pm_api_arg[0],
+					     pm_api_arg[1] ? pm_api_arg[1] :
+					     ZYNQMP_PM_MAX_LATENCY, 0);
+		break;
+	case PM_FORCE_POWERDOWN:
+		ret = eemi_ops->force_powerdown(pm_api_arg[0],
+						pm_api_arg[1] ? pm_api_arg[1] :
+						ZYNQMP_PM_REQUEST_ACK_NO);
+		break;
+	case PM_ABORT_SUSPEND:
+		ret = zynqmp_pm_abort_suspend(pm_api_arg[0] ? pm_api_arg[0] :
+					      ZYNQMP_PM_ABORT_REASON_UNKNOWN);
+		break;
+	case PM_REQUEST_WAKEUP:
+		ret = eemi_ops->request_wakeup(pm_api_arg[0],
+					       pm_api_arg[1], pm_api_arg[2],
+					       pm_api_arg[3] ? pm_api_arg[3] :
+					       ZYNQMP_PM_REQUEST_ACK_NO);
+		break;
+	case PM_SET_WAKEUP_SOURCE:
+		ret = eemi_ops->set_wakeup_source(pm_api_arg[0], pm_api_arg[1],
+						  pm_api_arg[2]);
+		break;
+	case PM_SYSTEM_SHUTDOWN:
+		ret = eemi_ops->system_shutdown(pm_api_arg[0], pm_api_arg[1]);
+		break;
+	case PM_REQUEST_NODE:
+		ret = eemi_ops->request_node(pm_api_arg[0],
+					     pm_api_arg[1] ? pm_api_arg[1] :
+					     ZYNQMP_PM_CAPABILITY_ACCESS,
+					     pm_api_arg[2] ? pm_api_arg[2] : 0,
+					     pm_api_arg[3] ? pm_api_arg[3] :
+					     ZYNQMP_PM_REQUEST_ACK_BLOCKING);
+		break;
+	case PM_RELEASE_NODE:
+		ret = eemi_ops->release_node(pm_api_arg[0]);
+		break;
+	case PM_SET_REQUIREMENT:
+		ret = eemi_ops->set_requirement(pm_api_arg[0],
+						pm_api_arg[1] ? pm_api_arg[1] :
+						ZYNQMP_PM_CAPABILITY_CONTEXT,
+						pm_api_arg[2] ?
+						pm_api_arg[2] : 0,
+						pm_api_arg[3] ? pm_api_arg[3] :
+						ZYNQMP_PM_REQUEST_ACK_BLOCKING);
+		break;
+	case PM_SET_MAX_LATENCY:
+		ret = eemi_ops->set_max_latency(pm_api_arg[0],
+						pm_api_arg[1] ? pm_api_arg[1] :
+						ZYNQMP_PM_MAX_LATENCY);
+		break;
+	case PM_SET_CONFIGURATION:
+		ret = eemi_ops->set_configuration(pm_api_arg[0]);
+		break;
+	case PM_GET_NODE_STATUS:
+		ret = eemi_ops->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_GET_OPERATING_CHARACTERISTIC:
+		ret = eemi_ops->get_operating_characteristic(pm_api_arg[0],
+				pm_api_arg[1] ? pm_api_arg[1] :
+				ZYNQMP_PM_OPERATING_CHARACTERISTIC_POWER,
+				&pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf,
+				"GET_OPERATING_CHARACTERISTIC:\n\tNodeId: %llu\n\tType: %llu\n\tResult: %u\n",
+				pm_api_arg[0], pm_api_arg[1],
+				pm_api_ret[0]);
+		break;
+	case PM_REGISTER_NOTIFIER:
+		ret = zynqmp_pm_register_notifier(pm_api_arg[0],
+						  pm_api_arg[1] ?
+						  pm_api_arg[1] : 0,
+						  pm_api_arg[2] ?
+						  pm_api_arg[2] : 0,
+						  pm_api_arg[3] ?
+						  pm_api_arg[3] : 0);
+		break;
+	case PM_RESET_ASSERT:
+		ret = eemi_ops->reset_assert(pm_api_arg[0], pm_api_arg[1]);
+		break;
+	case PM_RESET_GET_STATUS:
+		ret = eemi_ops->reset_get_status(pm_api_arg[0], &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf, "Reset status: %u\n",
+				pm_api_ret[0]);
+		break;
+	case PM_GET_CHIPID:
+		ret = eemi_ops->get_chipid(&pm_api_ret[0], &pm_api_ret[1]);
+		if (!ret)
+			sprintf(debugfs_buf, "Idcode: %#x, Version:%#x\n",
+				pm_api_ret[0], pm_api_ret[1]);
+		break;
+	case PM_PINCTRL_GET_FUNCTION:
+		ret = eemi_ops->pinctrl_get_function(pm_api_arg[0],
+						     &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf,
+				"Current set function for the pin: %u\n",
+				pm_api_ret[0]);
+		break;
+	case PM_PINCTRL_SET_FUNCTION:
+		ret = eemi_ops->pinctrl_set_function(pm_api_arg[0],
+						     pm_api_arg[1]);
+		break;
+	case PM_PINCTRL_CONFIG_PARAM_GET:
+		ret = eemi_ops->pinctrl_get_config(pm_api_arg[0], pm_api_arg[1],
+						   &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf,
+				"Pin: %llu, Param: %llu, Value: %u\n",
+				pm_api_arg[0], pm_api_arg[1],
+				pm_api_ret[0]);
+		break;
+	case PM_PINCTRL_CONFIG_PARAM_SET:
+		ret = eemi_ops->pinctrl_set_config(pm_api_arg[0],
+						   pm_api_arg[1],
+						   pm_api_arg[2]);
+		break;
+	case PM_IOCTL:
+		ret = eemi_ops->ioctl(pm_api_arg[0], pm_api_arg[1],
+				      pm_api_arg[2], pm_api_arg[3],
+				      &pm_api_ret[0]);
+		if (!ret && (pm_api_arg[1] == IOCTL_GET_RPU_OPER_MODE ||
+			     pm_api_arg[1] == IOCTL_GET_PLL_FRAC_MODE ||
+			     pm_api_arg[1] == IOCTL_GET_PLL_FRAC_DATA ||
+			     pm_api_arg[1] == IOCTL_READ_GGS ||
+			     pm_api_arg[1] == IOCTL_READ_PGGS))
+			sprintf(debugfs_buf, "IOCTL return value: %u\n",
+				pm_api_ret[1]);
+		break;
+	case PM_CLOCK_ENABLE:
+		ret = eemi_ops->clock_enable(pm_api_arg[0]);
+		break;
+	case PM_CLOCK_DISABLE:
+		ret = eemi_ops->clock_disable(pm_api_arg[0]);
+		break;
+	case PM_CLOCK_GETSTATE:
+		ret = eemi_ops->clock_getstate(pm_api_arg[0], &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf, "Clock state: %u\n",
+				pm_api_ret[0]);
+		break;
+	case PM_CLOCK_SETDIVIDER:
+		ret = eemi_ops->clock_setdivider(pm_api_arg[0], pm_api_arg[1]);
+		break;
+	case PM_CLOCK_GETDIVIDER:
+		ret = eemi_ops->clock_getdivider(pm_api_arg[0], &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf, "Divider Value: %d\n",
+				pm_api_ret[0]);
+		break;
+	case PM_CLOCK_SETRATE:
+		ret = eemi_ops->clock_setrate(pm_api_arg[0], pm_api_arg[1]);
+		break;
+	case PM_CLOCK_GETRATE:
+		ret = eemi_ops->clock_getrate(pm_api_arg[0], &rate);
+		if (!ret)
+			sprintf(debugfs_buf, "Clock rate :%llu\n", rate);
+		break;
+	case PM_CLOCK_SETPARENT:
+		ret = eemi_ops->clock_setparent(pm_api_arg[0], pm_api_arg[1]);
+		break;
+	case PM_CLOCK_GETPARENT:
+		ret = eemi_ops->clock_getparent(pm_api_arg[0], &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf,
+				"Clock parent Index: %u\n", pm_api_ret[0]);
+		break;
+	case PM_QUERY_DATA:
+	{
+		struct zynqmp_pm_query_data qdata = {0};
+
+		qdata.qid = pm_api_arg[0];
+		qdata.arg1 = pm_api_arg[1];
+		qdata.arg2 = pm_api_arg[2];
+		qdata.arg3 = pm_api_arg[3];
+
+		ret = eemi_ops->query_data(qdata, pm_api_ret);
+		if (!ret)
+			sprintf(debugfs_buf,
+				"data[0] = 0x%08x\ndata[1] = 0x%08x\n data[2] = 0x%08x\ndata[3] = 0x%08x\n",
+				pm_api_ret[0], pm_api_ret[1],
+				pm_api_ret[2], pm_api_ret[3]);
+		break;
+	}
+	default:
+		sprintf(debugfs_buf, "Unsupported PM-API request\n");
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+/**
+ * zynqmp_pm_debugfs_api_write - debugfs write function
+ * @file:	User file structure
+ * @ptr:	User entered PM-API string
+ * @len:	Length of the userspace buffer
+ * @off:	Offset within the file
+ *
+ * Return:	Number of bytes copied if PM-API request succeeds,
+ *		the corresponding error code otherwise
+ *
+ * Used for triggering pm api functions by writing
+ * echo <pm_api_id>	> /sys/kernel/debug/zynqmp_pm/power or
+ * echo <pm_api_name>	> /sys/kernel/debug/zynqmp_pm/power
+ */
+static ssize_t zynqmp_pm_debugfs_api_write(struct file *file,
+					   const char __user *ptr, size_t len,
+					   loff_t *off)
+{
+	char *kern_buff, *tmp_buff;
+	char *pm_api_req;
+	u32 pm_id = 0;
+	u64 pm_api_arg[4] = {0, 0, 0, 0};
+	/* Return values from PM APIs calls */
+	u32 pm_api_ret[4] = {0, 0, 0, 0};
+
+	int ret;
+	int i = 0;
+
+	strcpy(debugfs_buf, "");
+
+	if (*off != 0 || len == 0)
+		return -EINVAL;
+
+	kern_buff = kzalloc(len, GFP_KERNEL);
+	if (!kern_buff)
+		return -ENOMEM;
+
+	tmp_buff = kern_buff;
+
+	ret = strncpy_from_user(kern_buff, ptr, len);
+	if (ret < 0) {
+		ret = -EFAULT;
+		goto err;
+	}
+
+	/* Read the API name from a user request */
+	pm_api_req = strsep(&kern_buff, " ");
+
+	ret = get_pm_api_id(pm_api_req, &pm_id);
+	if (ret < 0)
+		goto err;
+
+	/* Read node_id and arguments from the PM-API request */
+	pm_api_req = strsep(&kern_buff, " ");
+	while ((i < ARRAY_SIZE(pm_api_arg)) && pm_api_req) {
+		pm_api_arg[i++] = zynqmp_pm_argument_value(pm_api_req);
+		pm_api_req = strsep(&kern_buff, " ");
+	}
+
+	ret = process_api_request(pm_id, pm_api_arg, pm_api_ret);
+
+err:
+	kfree(tmp_buff);
+	if (ret)
+		return ret;
+
+	return len;
+}
+
+/**
+ * zynqmp_pm_debugfs_api_read - debugfs read function
+ * @file:	User file structure
+ * @ptr:	Requested pm_api_version string
+ * @len:	Length of the userspace buffer
+ * @off:	Offset within the file
+ *
+ * Return:	Length of the version string on success
+ *		else error code.
+ */
+static ssize_t zynqmp_pm_debugfs_api_read(struct file *file, char __user *ptr,
+					  size_t len, loff_t *off)
+{
+	return simple_read_from_buffer(ptr, len, off, debugfs_buf,
+				       strlen(debugfs_buf));
+}
+
+/* Setup debugfs fops */
+static const struct file_operations fops_zynqmp_pm_dbgfs = {
+	.owner = THIS_MODULE,
+	.write = zynqmp_pm_debugfs_api_write,
+	.read = zynqmp_pm_debugfs_api_read,
+};
+
+/**
+ * zynqmp_pm_api_debugfs_init - Initialize debugfs interface
+ *
+ * Return:	None
+ */
+void zynqmp_pm_api_debugfs_init(void)
+{
+	struct dentry *root_dir;
+
+	/* Initialize debugfs interface */
+	root_dir = debugfs_create_dir("zynqmp-firmware", NULL);
+	debugfs_create_file("pm", 0660, root_dir, NULL,
+			    &fops_zynqmp_pm_dbgfs);
+}
diff --git a/drivers/firmware/xilinx/zynqmp/firmware.c b/drivers/firmware/xilinx/zynqmp/firmware.c
index 02266d9..3bb2c8e 100644
--- a/drivers/firmware/xilinx/zynqmp/firmware.c
+++ b/drivers/firmware/xilinx/zynqmp/firmware.c
@@ -19,6 +19,7 @@
 #include <linux/uaccess.h>
 
 #include <linux/firmware/xilinx/zynqmp/firmware.h>
+#include <linux/firmware/xilinx/zynqmp/firmware-debug.h>
 
 /**
  * zynqmp_pm_ret_code - Convert PMU-FW error codes to Linux error codes
@@ -1055,9 +1056,13 @@ static int zynqmp_firmware_init(void)
 	int ret;
 
 	ret = zynqmp_pm_ggs_init();
-	if (ret)
+	if (ret) {
 		pr_err("%s() GGS init fail with error %d\n",
 		       __func__, ret);
+		return ret;
+	}
+
+	zynqmp_pm_api_debugfs_init();
 
 	return ret;
 }
diff --git a/include/linux/firmware/xilinx/zynqmp/firmware-debug.h b/include/linux/firmware/xilinx/zynqmp/firmware-debug.h
new file mode 100644
index 0000000..eff5b53
--- /dev/null
+++ b/include/linux/firmware/xilinx/zynqmp/firmware-debug.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Xilinx Zynq MPSoC Firmware layer
+ *
+ *  Copyright (C) 2014-2018 Xilinx
+ *
+ *  Michal Simek <michal.simek@xxxxxxxxxx>
+ *  Davorin Mista <davorin.mista@xxxxxxxxxx>
+ *  Jolly Shah <jollys@xxxxxxxxxx>
+ *  Rajan Vaja <rajanv@xxxxxxxxxx>
+ */
+
+#ifndef __SOC_ZYNQMP_FIRMWARE_DEBUG_H__
+#define __SOC_ZYNQMP_FIRMWARE_DEBUG_H__
+
+#if IS_REACHABLE(CONFIG_ZYNQMP_FIRMWARE_DEBUG)
+void zynqmp_pm_api_debugfs_init(void);
+#else
+static inline void zynqmp_pm_api_debugfs_init(void) { }
+#endif
+
+#endif /* __SOC_ZYNQMP_FIRMWARE_DEBUG_H__ */
-- 
2.7.4