[PATCH 1/3] soc: qcom: Introduce Protection Domain Restart helpers

[Sibi Sankar]

Qualcomm SoCs (starting with MSM8998) allow for multiple protection domains
to run on the same Q6 sub-system. This allows for services like ATH10K WLAN
FW to have their own separate address space and crash/recover without
disrupting the modem and other PDs running on the same sub-system. The PDR
helpers introduces an abstraction that allows for tracking/controlling the
life cycle of protection domains running on various Q6 sub-systems.

Signed-off-by: Sibi Sankar <sibis@xxxxxxxxxxxxxx>
---
 drivers/soc/qcom/Kconfig         |   5 +
 drivers/soc/qcom/Makefile        |   1 +
 drivers/soc/qcom/pdr_interface.c | 685 +++++++++++++++++++++++++++++++
 drivers/soc/qcom/pdr_internal.h  | 375 +++++++++++++++++
 include/linux/soc/qcom/pdr.h     | 102 +++++
 include/linux/soc/qcom/qmi.h     |   1 +
 6 files changed, 1169 insertions(+)
 create mode 100644 drivers/soc/qcom/pdr_interface.c
 create mode 100644 drivers/soc/qcom/pdr_internal.h
 create mode 100644 include/linux/soc/qcom/pdr.h

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 79d826553ac82..5c4e76837f59b 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -76,6 +76,11 @@ config QCOM_OCMEM
           requirements. This is typically used by the GPU, camera/video, and
           audio components on some Snapdragon SoCs.
 
+config QCOM_PDR_HELPERS
+	tristate
+	depends on ARCH_QCOM || COMPILE_TEST
+	select QCOM_QMI_HELPERS
+
 config QCOM_PM
 	bool "Qualcomm Power Management"
 	depends on ARCH_QCOM && !ARM64
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 9fb35c8a495e1..5d6b83dc58e82 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_QCOM_GLINK_SSR) +=	glink_ssr.o
 obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
 obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
 obj-$(CONFIG_QCOM_OCMEM)	+= ocmem.o
+obj-$(CONFIG_QCOM_PDR_HELPERS)	+= pdr_interface.o
 obj-$(CONFIG_QCOM_PM)	+=	spm.o
 obj-$(CONFIG_QCOM_QMI_HELPERS)	+= qmi_helpers.o
 qmi_helpers-y	+= qmi_encdec.o qmi_interface.o
diff --git a/drivers/soc/qcom/pdr_interface.c b/drivers/soc/qcom/pdr_interface.c
new file mode 100644
index 0000000000000..2df8167663c85
--- /dev/null
+++ b/drivers/soc/qcom/pdr_interface.c
@@ -0,0 +1,685 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/completion.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/qrtr.h>
+#include <linux/string.h>
+#include <linux/workqueue.h>
+
+#include "pdr_internal.h"
+
+struct pdr_list_node {
+	u16 transaction_id;
+	struct pdr_service *pds;
+	struct list_head node;
+};
+
+static int servreg_locator_new_server(struct qmi_handle *qmi,
+				      struct qmi_service *svc)
+{
+	struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
+					      servloc_client);
+
+	/* Create a Local client port for QMI communication */
+	pdr->servloc_addr.sq_family = AF_QIPCRTR;
+	pdr->servloc_addr.sq_node = svc->node;
+	pdr->servloc_addr.sq_port = svc->port;
+
+	complete_all(&pdr->locator_available);
+
+	return 0;
+}
+
+static void servreg_locator_del_server(struct qmi_handle *qmi,
+				       struct qmi_service *svc)
+{
+	struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
+					      servloc_client);
+
+	reinit_completion(&pdr->locator_available);
+}
+
+static struct qmi_ops service_locator_ops = {
+	.new_server = servreg_locator_new_server,
+	.del_server = servreg_locator_del_server,
+};
+
+static int pdr_register_listener(struct pdr_handle *pdr,
+				 struct pdr_service *pds,
+				 bool enable)
+{
+	struct servreg_register_listener_resp resp;
+	struct servreg_register_listener_req req;
+	struct qmi_txn txn;
+	int ret;
+
+	ret = qmi_txn_init(&pdr->servreg_client, &txn,
+			   servreg_register_listener_resp_ei,
+			   &resp);
+
+	if (ret < 0)
+		return ret;
+
+	req.enable = enable;
+	strcpy(req.service_path, pds->service_path);
+
+	ret = qmi_send_request(&pdr->servreg_client, &pdr->servreg_addr,
+			       &txn, SERVREG_REGISTER_LISTENER_REQ,
+			       SERVREG_REGISTER_LISTENER_REQ_LEN,
+			       servreg_register_listener_req_ei,
+			       &req);
+	if (ret < 0) {
+		qmi_txn_cancel(&txn);
+		return ret;
+	}
+
+	ret = qmi_txn_wait(&txn, 5 * HZ);
+	if (ret < 0) {
+		pr_err("PDR: %s register listener txn wait failed: %d\n",
+		       pds->service_path, ret);
+		return ret;
+	}
+
+	/* Check the response */
+	if (resp.resp.result != QMI_RESULT_SUCCESS_V01) {
+		pr_err("PDR: %s register listener failed: 0x%x\n",
+		       pds->service_path, resp.resp.error);
+		return ret;
+	}
+
+	if ((int)resp.curr_state < INT_MIN || (int)resp.curr_state > INT_MAX)
+		pr_err("PDR: %s notification state invalid: 0x%x\n",
+		       pds->service_path, resp.curr_state);
+
+	pds->state = resp.curr_state;
+
+	return 0;
+}
+
+static void pdr_servreg_work(struct work_struct *work)
+{
+	struct pdr_handle *pdr = container_of(work, struct pdr_handle,
+					      servreg_work);
+	struct pdr_list_node *servreg, *tmp;
+	struct pdr_service *pds;
+
+	list_for_each_entry_safe(servreg, tmp, &pdr->servreg_list, node) {
+		pds = servreg->pds;
+		pdr_register_listener(pdr, pds, true);
+		pdr->status(pdr, pds);
+		list_del(&servreg->node);
+		kfree(servreg);
+	}
+}
+
+static int servreg_notifier_new_server(struct qmi_handle *qmi,
+				       struct qmi_service *svc)
+{
+	struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
+					      servreg_client);
+	struct pdr_list_node *servreg;
+	struct pdr_service *pds, *tmp;
+
+	/* Create a Local client port for QMI communication */
+	pdr->servreg_addr.sq_family = AF_QIPCRTR;
+	pdr->servreg_addr.sq_node = svc->node;
+	pdr->servreg_addr.sq_port = svc->port;
+
+	servreg = kzalloc(sizeof(*servreg), GFP_KERNEL);
+	if (!servreg)
+		return -ENOMEM;
+
+	list_for_each_entry_safe(pds, tmp, &pdr->lookups, node) {
+		if (pds->service == svc->service &&
+		    pds->instance == svc->instance) {
+			pds->service_connected = true;
+			servreg->pds = pds;
+			mutex_lock(&pdr->list_lock);
+			list_add_tail(&servreg->node, &pdr->servreg_list);
+			mutex_unlock(&pdr->list_lock);
+			break;
+		}
+	}
+
+	queue_work(pdr->servreg_wq, &pdr->servreg_work);
+
+	return 0;
+}
+
+static void pdr_servdel_work(struct work_struct *work)
+{
+	struct pdr_handle *pdr = container_of(work, struct pdr_handle,
+					      servdel_work);
+	struct pdr_list_node *servreg, *tmp;
+	struct pdr_service *pds;
+
+	list_for_each_entry_safe(servreg, tmp, &pdr->servdel_list, node) {
+		pds = servreg->pds;
+		pds->service_connected = false;
+		pds->state = SERVREG_SERVICE_STATE_DOWN;
+		pdr->status(pdr, pds);
+		list_del(&servreg->node);
+		kfree(servreg);
+	}
+}
+
+static void servreg_notifier_del_server(struct qmi_handle *qmi,
+					struct qmi_service *svc)
+{
+	struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
+					      servreg_client);
+	struct pdr_list_node *servreg;
+	struct pdr_service *pds, *tmp;
+
+	servreg = kzalloc(sizeof(*servreg), GFP_KERNEL);
+	if (!servreg)
+		return;
+
+	list_for_each_entry_safe(pds, tmp, &pdr->lookups, node) {
+		if (pds->service == svc->service &&
+		    pds->instance == svc->instance) {
+			servreg->pds = pds;
+			mutex_lock(&pdr->list_lock);
+			list_add_tail(&servreg->node, &pdr->servdel_list);
+			mutex_unlock(&pdr->list_lock);
+			break;
+		}
+	}
+
+	queue_work(pdr->servreg_wq, &pdr->servdel_work);
+}
+
+static struct qmi_ops service_notifier_ops = {
+	.new_server = servreg_notifier_new_server,
+	.del_server = servreg_notifier_del_server,
+};
+
+static int pdr_send_indack_msg(struct pdr_handle *pdr, struct pdr_service *pds,
+			       u16 tid)
+{
+	struct servreg_set_ack_resp resp;
+	struct servreg_set_ack_req req;
+	struct qmi_txn txn;
+	int ret;
+
+	ret = qmi_txn_init(&pdr->servreg_client, &txn, servreg_set_ack_resp_ei,
+			   &resp);
+	if (ret < 0)
+		return ret;
+
+	req.transaction_id = tid;
+	strcpy(req.service_path, pds->service_path);
+
+	ret = qmi_send_request(&pdr->servreg_client, &pdr->servreg_addr,
+			       &txn, SERVREG_SET_ACK_REQ,
+			       SERVREG_SET_ACK_REQ_LEN,
+			       servreg_set_ack_req_ei,
+			       &req);
+	if (ret < 0) {
+		qmi_txn_cancel(&txn);
+		return ret;
+	}
+
+	ret = qmi_txn_wait(&txn, 5 * HZ);
+	if (ret < 0) {
+		pr_err("PDR: %s indication ack txn wait failed: %d\n",
+		       pds->service_path, ret);
+		return ret;
+	}
+
+	/* Check the response */
+	if (resp.resp.result != QMI_RESULT_SUCCESS_V01)
+		pr_err("PDR: %s indication ack failed: 0x%x\n",
+		       pds->service_path, resp.resp.error);
+
+	return 0;
+}
+
+static void pdr_indack_work(struct work_struct *work)
+{
+	struct pdr_handle *pdr = container_of(work, struct pdr_handle,
+					      indack_work);
+	struct pdr_list_node *ind, *tmp;
+	struct pdr_service *pds;
+
+	list_for_each_entry_safe(ind, tmp, &pdr->indack_list, node) {
+		pds = ind->pds;
+		pdr_send_indack_msg(pdr, pds, ind->transaction_id);
+		pdr->status(pdr, pds);
+		list_del(&ind->node);
+		kfree(ind);
+	}
+}
+
+static void pdr_servreg_ind_cb(struct qmi_handle *qmi,
+			       struct sockaddr_qrtr *sq,
+			       struct qmi_txn *txn, const void *data)
+{
+	struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
+					      servreg_client);
+	const struct servreg_state_updated_ind *ind_msg = data;
+	struct pdr_list_node *ind;
+	struct pdr_service *pds;
+
+	if (!ind_msg || !ind_msg->service_path ||
+	    strlen(ind_msg->service_path) > (SERVREG_NAME_LENGTH + 1))
+		return;
+
+	list_for_each_entry(pds, &pdr->lookups, node) {
+		if (!strcmp(pds->service_path, ind_msg->service_path))
+			goto found;
+	}
+	return;
+
+found:
+	pds->state = ind_msg->curr_state;
+
+	ind = kzalloc(sizeof(*ind), GFP_KERNEL);
+	if (!ind)
+		return;
+
+	pr_info("PDR: Indication received from %s, state: 0x%x, trans-id: %d\n",
+		ind_msg->service_path, ind_msg->curr_state,
+		ind_msg->transaction_id);
+
+	ind->transaction_id = ind_msg->transaction_id;
+	ind->pds = pds;
+
+	mutex_lock(&pdr->list_lock);
+	list_add_tail(&ind->node, &pdr->indack_list);
+	mutex_unlock(&pdr->list_lock);
+
+	queue_work(pdr->indack_wq, &pdr->indack_work);
+}
+
+static struct qmi_msg_handler qmi_indication_handler[] = {
+	{
+		.type = QMI_INDICATION,
+		.msg_id = SERVREG_STATE_UPDATED_IND_ID,
+		.ei = servreg_state_updated_ind_ei,
+		.decoded_size = sizeof(struct servreg_state_updated_ind),
+		.fn = pdr_servreg_ind_cb,
+	},
+	{}
+};
+
+static int pdr_get_domain_list(struct servreg_get_domain_list_req *req,
+			       struct servreg_get_domain_list_resp *resp,
+			       struct pdr_handle *pdr)
+{
+	struct qmi_txn txn;
+	int ret;
+
+	ret = qmi_txn_init(&pdr->servloc_client, &txn,
+			   servreg_get_domain_list_resp_ei, resp);
+	if (ret < 0)
+		return ret;
+
+	ret = qmi_send_request(&pdr->servloc_client,
+			       &pdr->servloc_addr,
+			       &txn, SERVREG_GET_DOMAIN_LIST_REQ,
+			       SERVREG_GET_DOMAIN_LIST_REQ_MAX_LEN,
+			       servreg_get_domain_list_req_ei,
+			       req);
+	if (ret < 0) {
+		qmi_txn_cancel(&txn);
+		return ret;
+	}
+
+	ret = qmi_txn_wait(&txn, 5 * HZ);
+	if (ret < 0) {
+		pr_err("PDR: %s get domain list txn wait failed: %d\n",
+		       req->service_name, ret);
+		return ret;
+	}
+
+	/* Check the response */
+	if (resp->resp.result != QMI_RESULT_SUCCESS_V01) {
+		pr_err("PDR: %s get domain list failed: 0x%x\n",
+		       req->service_name, resp->resp.error);
+		return -EREMOTEIO;
+	}
+
+	return ret;
+}
+
+static int pdr_locate_service(struct pdr_handle *pdr, struct pdr_service *pds)
+{
+	struct servreg_get_domain_list_resp *resp = NULL;
+	struct servreg_get_domain_list_req req;
+	int db_rev_count = 0, domains_read = 0;
+	struct servreg_location_entry *entry;
+	int ret, i;
+
+	resp = kzalloc(sizeof(*resp), GFP_KERNEL);
+	if (!resp)
+		return -ENOMEM;
+
+	/* Prepare req message */
+	strcpy(req.service_name, pds->service_name);
+	req.domain_offset_valid = true;
+	req.domain_offset = 0;
+
+	do {
+		req.domain_offset = domains_read;
+		ret = pdr_get_domain_list(&req, resp, pdr);
+		if (ret < 0)
+			goto out;
+
+		if (!domains_read)
+			db_rev_count = resp->db_rev_count;
+
+		if (db_rev_count != resp->db_rev_count) {
+			ret = -EAGAIN;
+			goto out;
+		}
+
+		for (i = domains_read; i < resp->domain_list_len; i++) {
+			entry = &resp->domain_list[i];
+
+			if (strlen(entry->name) > (SERVREG_NAME_LENGTH + 1))
+				continue;
+
+			if (!strcmp(entry->name, pds->service_path)) {
+				pds->service_data_valid = entry->service_data_valid;
+				pds->service_data = entry->service_data;
+				pds->instance = entry->instance;
+				goto out;
+			}
+		}
+
+		/* Update ret to indicate that the service is not yet found */
+		ret = -EINVAL;
+
+		/* Always read total_domains from the response msg */
+		if (resp->domain_list_len >  resp->total_domains)
+			resp->domain_list_len = resp->total_domains;
+
+		domains_read += resp->domain_list_len;
+	} while (domains_read < resp->total_domains);
+out:
+	kfree(resp);
+	return ret;
+}
+
+static void pdr_servloc_work(struct work_struct *work)
+{
+	struct pdr_handle *pdr = container_of(work, struct pdr_handle,
+					      servloc_work);
+	struct pdr_list_node *servloc, *tmp;
+	struct pdr_service *pds;
+	int ret;
+
+	list_for_each_entry_safe(servloc, tmp, &pdr->servloc_list, node) {
+		pds = servloc->pds;
+
+		/* wait for PD Mapper to come up */
+		ret = wait_for_completion_timeout(&pdr->locator_available, 10 * HZ);
+		if (!ret) {
+			pr_err("PDR: SERVICE LOCATOR service wait failed\n");
+			ret = -ETIMEDOUT;
+			goto err;
+		}
+
+		ret = pdr_locate_service(pdr, pds);
+		if (ret < 0) {
+			pr_err("PDR: service lookup for %s failed: %d\n",
+			       pds->service_name, ret);
+			goto err;
+		}
+
+		qmi_add_lookup(&pdr->servreg_client, pds->service, 1,
+			       pds->instance);
+err:
+		list_del(&servloc->node);
+		kfree(servloc);
+
+		/* cleanup pds on error */
+		if (ret < 0) {
+			pds->state = SERVREG_LOCATOR_ERR;
+			pdr->status(pdr, pds);
+			list_del(&pds->node);
+			kfree(pds);
+		}
+	}
+}
+
+/**
+ * pdr_add_lookup() - register a tracking request for a PD
+ * @pdr:		PDR client handle
+ * @service_name:	service name of the tracking request
+ * @service_path:	service path of the tracking request
+ *
+ * Registering a pdr lookup allows for tracking the life cycle of the PD.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int pdr_add_lookup(struct pdr_handle *pdr, const char *service_name,
+		   const char *service_path)
+{
+	struct pdr_service *pds, *pds_iter, *tmp;
+	struct pdr_list_node *servloc;
+	int ret;
+
+	if (!service_name || strlen(service_name) > (SERVREG_NAME_LENGTH + 1) ||
+	    !service_path || strlen(service_path) > (SERVREG_NAME_LENGTH + 1))
+		return -EINVAL;
+
+	servloc = kzalloc(sizeof(*servloc), GFP_KERNEL);
+	if (!servloc)
+		return -ENOMEM;
+
+	pds = kzalloc(sizeof(*pds), GFP_KERNEL);
+	if (!pds) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	pds->service = SERVREG_NOTIFIER_SERVICE;
+	strcpy(pds->service_name, service_name);
+	strcpy(pds->service_path, service_path);
+	servloc->pds = pds;
+
+	mutex_lock(&pdr->list_lock);
+	list_for_each_entry_safe(pds_iter, tmp, &pdr->lookups, node) {
+		if (!strcmp(pds_iter->service_path, service_path)) {
+			mutex_unlock(&pdr->list_lock);
+			ret = -EALREADY;
+			goto err;
+		}
+	}
+
+	list_add(&pds->node, &pdr->lookups);
+	list_add(&servloc->node, &pdr->servloc_list);
+	mutex_unlock(&pdr->list_lock);
+
+	schedule_work(&pdr->servloc_work);
+
+	return 0;
+err:
+	kfree(pds);
+	kfree(servloc);
+
+	return ret;
+}
+EXPORT_SYMBOL(pdr_add_lookup);
+
+/**
+ * pdr_restart_pd() - restart PD
+ * @pdr:		PDR client handle
+ * @service_path:	service path of restart request
+ *
+ * Restarts the PD tracked by the PDR client handle for a given service path.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int pdr_restart_pd(struct pdr_handle *pdr, const char *service_path)
+{
+	struct servreg_restart_pd_req req;
+	struct servreg_restart_pd_resp resp;
+	struct pdr_service *pds = NULL, *pds_iter, *tmp;
+	struct qmi_txn txn;
+	int ret;
+
+	if (!service_path || strlen(service_path) > (SERVREG_NAME_LENGTH + 1))
+		return -EINVAL;
+
+	list_for_each_entry_safe(pds_iter, tmp, &pdr->lookups, node) {
+		if (!pds_iter->service_connected)
+			continue;
+
+		if (!strcmp(pds_iter->service_path, service_path)) {
+			pds = pds_iter;
+			break;
+		}
+	}
+
+	if (!pds)
+		return -EINVAL;
+
+	/* Prepare req message */
+	strcpy(req.service_path, pds->service_path);
+
+	ret = qmi_txn_init(&pdr->servreg_client, &txn,
+			   servreg_restart_pd_resp_ei,
+			   &resp);
+	if (ret < 0)
+		return ret;
+
+	ret = qmi_send_request(&pdr->servreg_client, &pdr->servreg_addr,
+			       &txn, SERVREG_RESTART_PD_REQ,
+			       SERVREG_RESTART_PD_REQ_MAX_LEN,
+			       servreg_restart_pd_req_ei, &req);
+	if (ret < 0) {
+		qmi_txn_cancel(&txn);
+		return ret;
+	}
+
+	ret = qmi_txn_wait(&txn, 5 * HZ);
+	if (ret < 0) {
+		pr_err("PDR: %s PD restart txn wait failed: %d\n",
+		       pds->service_path, ret);
+		return ret;
+	}
+
+	/* Check response if PDR is disabled */
+	if (resp.resp.result == QMI_RESULT_FAILURE_V01 &&
+	    resp.resp.error == QMI_ERR_DISABLED_V01) {
+		pr_err("PDR: %s PD restart is disabled: 0x%x\n",
+		       pds->service_path, resp.resp.error);
+		return -EOPNOTSUPP;
+	}
+
+	/* Check the response for other error case*/
+	if (resp.resp.result != QMI_RESULT_SUCCESS_V01) {
+		pr_err("PDR: %s request for PD restart failed: 0x%x\n",
+		       pds->service_path, resp.resp.error);
+		return -EREMOTEIO;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(pdr_restart_pd);
+
+/**
+ * pdr_handle_init() - initialize the PDR client handle
+ * @pdr:	PDR client handle
+ * @status:	function to be called on PD state change
+ *
+ * Initializes the PDR client handle to allow for tracking/restart of PDs.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int pdr_handle_init(struct pdr_handle *pdr,
+		    int (*status)(struct pdr_handle *pdr,
+				  struct pdr_service *pds))
+{
+	int ret;
+
+	if (!status)
+		return -EINVAL;
+
+	pdr->status = *status;
+
+	mutex_init(&pdr->list_lock);
+	init_completion(&pdr->locator_available);
+
+	INIT_LIST_HEAD(&pdr->lookups);
+	INIT_LIST_HEAD(&pdr->servloc_list);
+	INIT_LIST_HEAD(&pdr->servreg_list);
+	INIT_LIST_HEAD(&pdr->servdel_list);
+	INIT_LIST_HEAD(&pdr->indack_list);
+
+	INIT_WORK(&pdr->servloc_work, pdr_servloc_work);
+	INIT_WORK(&pdr->servreg_work, pdr_servreg_work);
+	INIT_WORK(&pdr->servdel_work, pdr_servdel_work);
+	INIT_WORK(&pdr->indack_work, pdr_indack_work);
+
+	pdr->servreg_wq = create_singlethread_workqueue("pdr_servreg_wq");
+	if (!pdr->servreg_wq)
+		return -ENOMEM;
+
+	pdr->indack_wq = alloc_ordered_workqueue("pdr_indack_wq", WQ_HIGHPRI);
+	if (!pdr->indack_wq) {
+		ret = -ENOMEM;
+		goto destroy_servreg;
+	}
+
+	ret = qmi_handle_init(&pdr->servloc_client,
+			      SERVREG_GET_DOMAIN_LIST_RESP_MAX_LEN,
+			      &service_locator_ops, NULL);
+	if (ret < 0)
+		goto destroy_indack;
+
+	ret = qmi_handle_init(&pdr->servreg_client,
+			      SERVREG_STATE_UPDATED_IND_MAX_LEN,
+			      &service_notifier_ops, qmi_indication_handler);
+	if (ret < 0)
+		goto release_handle;
+
+	qmi_add_lookup(&pdr->servloc_client, SERVREG_LOCATOR_SERVICE, 1, 1);
+
+	return 0;
+
+release_handle:
+	qmi_handle_release(&pdr->servloc_client);
+destroy_indack:
+	destroy_workqueue(pdr->indack_wq);
+destroy_servreg:
+	destroy_workqueue(pdr->servreg_wq);
+
+	return ret;
+}
+EXPORT_SYMBOL(pdr_handle_init);
+
+/**
+ * pdr_handle_release() - release the PDR client handle
+ * @pdr:	PDR client handle
+ *
+ * Cleans up pending tracking requests and releases the underlying qmi handles.
+ */
+void pdr_handle_release(struct pdr_handle *pdr)
+{
+	struct pdr_service *pds, *tmp;
+
+	qmi_handle_release(&pdr->servloc_client);
+	qmi_handle_release(&pdr->servreg_client);
+
+	cancel_work_sync(&pdr->servloc_work);
+	cancel_work_sync(&pdr->servreg_work);
+	cancel_work_sync(&pdr->servdel_work);
+	cancel_work_sync(&pdr->indack_work);
+
+	destroy_workqueue(pdr->servreg_wq);
+	destroy_workqueue(pdr->indack_wq);
+
+	list_for_each_entry_safe(pds, tmp, &pdr->lookups, node) {
+		list_del(&pds->node);
+		kfree(pds);
+	}
+}
+EXPORT_SYMBOL(pdr_handle_release);
diff --git a/drivers/soc/qcom/pdr_internal.h b/drivers/soc/qcom/pdr_internal.h
new file mode 100644
index 0000000000000..adaf85d509507
--- /dev/null
+++ b/drivers/soc/qcom/pdr_internal.h
@@ -0,0 +1,375 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/soc/qcom/pdr.h>
+
+#define SERVREG_LOCATOR_SERVICE				0x40
+#define SERVREG_NOTIFIER_SERVICE			0x42
+
+#define SERVREG_REGISTER_LISTENER_REQ			0x20
+#define SERVREG_GET_DOMAIN_LIST_REQ			0x21
+#define SERVREG_STATE_UPDATED_IND_ID			0x22
+#define SERVREG_SET_ACK_REQ				0x23
+#define SERVREG_RESTART_PD_REQ				0x24
+
+#define SERVREG_DOMAIN_LIST_LENGTH			32
+#define SERVREG_RESTART_PD_REQ_MAX_LEN			67
+#define SERVREG_REGISTER_LISTENER_REQ_LEN		71
+#define SERVREG_SET_ACK_REQ_LEN				72
+#define SERVREG_GET_DOMAIN_LIST_REQ_MAX_LEN		74
+#define SERVREG_STATE_UPDATED_IND_MAX_LEN		79
+#define SERVREG_GET_DOMAIN_LIST_RESP_MAX_LEN		2389
+
+struct servreg_location_entry {
+	char name[SERVREG_NAME_LENGTH + 1];
+	u8 service_data_valid;
+	u32 service_data;
+	u32 instance;
+};
+
+struct qmi_elem_info servreg_location_entry_ei[] = {
+	{
+		.data_type      = QMI_STRING,
+		.elem_len       = SERVREG_NAME_LENGTH + 1,
+		.elem_size      = sizeof(char),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0,
+		.offset         = offsetof(struct servreg_location_entry,
+					   name),
+	},
+	{
+		.data_type      = QMI_UNSIGNED_4_BYTE,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0,
+		.offset         = offsetof(struct servreg_location_entry,
+					   instance),
+	},
+	{
+		.data_type      = QMI_UNSIGNED_1_BYTE,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0,
+		.offset         = offsetof(struct servreg_location_entry,
+					   service_data_valid),
+	},
+	{
+		.data_type      = QMI_UNSIGNED_4_BYTE,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0,
+		.offset         = offsetof(struct servreg_location_entry,
+					   service_data),
+	},
+	{}
+};
+
+struct servreg_get_domain_list_req {
+	char service_name[SERVREG_NAME_LENGTH + 1];
+	u8 domain_offset_valid;
+	u32 domain_offset;
+};
+
+struct qmi_elem_info servreg_get_domain_list_req_ei[] = {
+	{
+		.data_type      = QMI_STRING,
+		.elem_len       = SERVREG_NAME_LENGTH + 1,
+		.elem_size      = sizeof(char),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x01,
+		.offset         = offsetof(struct servreg_get_domain_list_req,
+					   service_name),
+	},
+	{
+		.data_type      = QMI_OPT_FLAG,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x10,
+		.offset         = offsetof(struct servreg_get_domain_list_req,
+					   domain_offset_valid),
+	},
+	{
+		.data_type      = QMI_UNSIGNED_4_BYTE,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x10,
+		.offset         = offsetof(struct servreg_get_domain_list_req,
+					   domain_offset),
+	},
+	{}
+};
+
+struct servreg_get_domain_list_resp {
+	struct qmi_response_type_v01 resp;
+	u8 total_domains_valid;
+	u16 total_domains;
+	u8 db_rev_count_valid;
+	u16 db_rev_count;
+	u8 domain_list_valid;
+	u32 domain_list_len;
+	struct servreg_location_entry domain_list[SERVREG_DOMAIN_LIST_LENGTH];
+};
+
+struct qmi_elem_info servreg_get_domain_list_resp_ei[] = {
+	{
+		.data_type      = QMI_STRUCT,
+		.elem_len       = 1,
+		.elem_size      = sizeof(struct qmi_response_type_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x02,
+		.offset         = offsetof(struct servreg_get_domain_list_resp,
+					   resp),
+		.ei_array      = qmi_response_type_v01_ei,
+	},
+	{
+		.data_type      = QMI_OPT_FLAG,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x10,
+		.offset         = offsetof(struct servreg_get_domain_list_resp,
+					   total_domains_valid),
+	},
+	{
+		.data_type      = QMI_UNSIGNED_2_BYTE,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u16),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x10,
+		.offset         = offsetof(struct servreg_get_domain_list_resp,
+					   total_domains),
+	},
+	{
+		.data_type      = QMI_OPT_FLAG,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x11,
+		.offset         = offsetof(struct servreg_get_domain_list_resp,
+					   db_rev_count_valid),
+	},
+	{
+		.data_type      = QMI_UNSIGNED_2_BYTE,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u16),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x11,
+		.offset         = offsetof(struct servreg_get_domain_list_resp,
+					   db_rev_count),
+	},
+	{
+		.data_type      = QMI_OPT_FLAG,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x12,
+		.offset         = offsetof(struct servreg_get_domain_list_resp,
+					   domain_list_valid),
+	},
+	{
+		.data_type      = QMI_DATA_LEN,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x12,
+		.offset         = offsetof(struct servreg_get_domain_list_resp,
+					   domain_list_len),
+	},
+	{
+		.data_type      = QMI_STRUCT,
+		.elem_len       = SERVREG_DOMAIN_LIST_LENGTH,
+		.elem_size      = sizeof(struct servreg_location_entry),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x12,
+		.offset         = offsetof(struct servreg_get_domain_list_resp,
+					   domain_list),
+		.ei_array      = servreg_location_entry_ei,
+	},
+	{}
+};
+
+struct servreg_register_listener_req {
+	u8 enable;
+	char service_path[SERVREG_NAME_LENGTH + 1];
+};
+
+struct qmi_elem_info servreg_register_listener_req_ei[] = {
+	{
+		.data_type      = QMI_UNSIGNED_1_BYTE,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x01,
+		.offset         = offsetof(struct servreg_register_listener_req,
+					   enable),
+	},
+	{
+		.data_type      = QMI_STRING,
+		.elem_len       = SERVREG_NAME_LENGTH + 1,
+		.elem_size      = sizeof(char),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x02,
+		.offset         = offsetof(struct servreg_register_listener_req,
+					   service_path),
+	},
+	{}
+};
+
+struct servreg_register_listener_resp {
+	struct qmi_response_type_v01 resp;
+	u8 curr_state_valid;
+	enum servreg_service_state curr_state;
+};
+
+struct qmi_elem_info servreg_register_listener_resp_ei[] = {
+	{
+		.data_type      = QMI_STRUCT,
+		.elem_len       = 1,
+		.elem_size      = sizeof(struct qmi_response_type_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x02,
+		.offset         = offsetof(struct servreg_register_listener_resp,
+					   resp),
+		.ei_array      = qmi_response_type_v01_ei,
+	},
+	{
+		.data_type      = QMI_OPT_FLAG,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x10,
+		.offset         = offsetof(struct servreg_register_listener_resp,
+					   curr_state_valid),
+	},
+	{
+		.data_type      = QMI_SIGNED_4_BYTE_ENUM,
+		.elem_len       = 1,
+		.elem_size      = sizeof(enum servreg_service_state),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x10,
+		.offset         = offsetof(struct servreg_register_listener_resp,
+					   curr_state),
+	},
+	{}
+};
+
+struct servreg_restart_pd_req {
+	char service_path[SERVREG_NAME_LENGTH + 1];
+};
+
+struct qmi_elem_info servreg_restart_pd_req_ei[] = {
+	{
+		.data_type      = QMI_STRING,
+		.elem_len       = SERVREG_NAME_LENGTH + 1,
+		.elem_size      = sizeof(char),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x01,
+		.offset         = offsetof(struct servreg_restart_pd_req,
+					   service_path),
+	},
+	{}
+};
+
+struct servreg_restart_pd_resp {
+	struct qmi_response_type_v01 resp;
+};
+
+struct qmi_elem_info servreg_restart_pd_resp_ei[] = {
+	{
+		.data_type      = QMI_STRUCT,
+		.elem_len       = 1,
+		.elem_size      = sizeof(struct qmi_response_type_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x02,
+		.offset         = offsetof(struct servreg_restart_pd_resp,
+					   resp),
+		.ei_array      = qmi_response_type_v01_ei,
+	},
+	{}
+};
+
+struct servreg_state_updated_ind {
+	enum servreg_service_state curr_state;
+	char service_path[SERVREG_NAME_LENGTH + 1];
+	u16 transaction_id;
+};
+
+struct qmi_elem_info servreg_state_updated_ind_ei[] = {
+	{
+		.data_type      = QMI_SIGNED_4_BYTE_ENUM,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x01,
+		.offset         = offsetof(struct servreg_state_updated_ind,
+					   curr_state),
+	},
+	{
+		.data_type      = QMI_STRING,
+		.elem_len       = SERVREG_NAME_LENGTH + 1,
+		.elem_size      = sizeof(char),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x02,
+		.offset         = offsetof(struct servreg_state_updated_ind,
+					   service_path),
+	},
+	{
+		.data_type      = QMI_UNSIGNED_2_BYTE,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u16),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x03,
+		.offset         = offsetof(struct servreg_state_updated_ind,
+					   transaction_id),
+	},
+	{}
+};
+
+struct servreg_set_ack_req {
+	char service_path[SERVREG_NAME_LENGTH + 1];
+	u16 transaction_id;
+};
+
+struct qmi_elem_info servreg_set_ack_req_ei[] = {
+	{
+		.data_type      = QMI_STRING,
+		.elem_len       = SERVREG_NAME_LENGTH + 1,
+		.elem_size      = sizeof(char),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x01,
+		.offset         = offsetof(struct servreg_set_ack_req,
+					   service_path),
+	},
+	{
+		.data_type      = QMI_UNSIGNED_2_BYTE,
+		.elem_len       = 1,
+		.elem_size      = sizeof(u16),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x02,
+		.offset         = offsetof(struct servreg_set_ack_req,
+					   transaction_id),
+	},
+	{}
+};
+
+struct servreg_set_ack_resp {
+	struct qmi_response_type_v01 resp;
+};
+
+struct qmi_elem_info servreg_set_ack_resp_ei[] = {
+	{
+		.data_type      = QMI_STRUCT,
+		.elem_len       = 1,
+		.elem_size      = sizeof(struct qmi_response_type_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type       = 0x02,
+		.offset         = offsetof(struct servreg_set_ack_resp,
+					   resp),
+		.ei_array       = qmi_response_type_v01_ei,
+	},
+	{}
+};
diff --git a/include/linux/soc/qcom/pdr.h b/include/linux/soc/qcom/pdr.h
new file mode 100644
index 0000000000000..22781e8cca567
--- /dev/null
+++ b/include/linux/soc/qcom/pdr.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __QCOM_PDR_HELPER__
+#define __QCOM_PDR_HELPER__
+
+#include <linux/soc/qcom/qmi.h>
+
+#define SERVREG_NAME_LENGTH	64
+
+enum servreg_service_state {
+	SERVREG_LOCATOR_ERR = 0x1,
+	SERVREG_SERVICE_STATE_DOWN = 0x0FFFFFFF,
+	SERVREG_SERVICE_STATE_UP = 0x1FFFFFFF,
+	SERVREG_SERVICE_STATE_EARLY_DOWN = 0x2FFFFFFF,
+	SERVREG_SERVICE_STATE_UNINIT = 0x7FFFFFFF,
+};
+
+/**
+ * struct pdr_service - context to track lookups/restarts
+ * @service_name:		name of the service running on the PD
+ * @service_path:		service path of the PD
+ * @service_data_valid:		indicates if service_data field has valid data
+ * @service_data:		service data provided by servreg_locator service
+ * @service_connected:		current state of servreg_notifier qmi service
+ * @state:			current state of PD
+ * @service:			servreg_notifer service type
+ * @instance:			instance id of the @service
+ * @priv:			handle for client's use
+ * @node:			list_head for house keeping
+ */
+struct pdr_service {
+	char service_name[SERVREG_NAME_LENGTH + 1];
+	char service_path[SERVREG_NAME_LENGTH + 1];
+
+	u8 service_data_valid;
+	u32 service_data;
+
+	bool service_connected;
+	int state;
+
+	unsigned int instance;
+	unsigned int service;
+
+	void *priv;
+	struct list_head node;
+};
+
+/**
+ * struct pdr_handle - PDR context
+ * @servloc_client:	servreg_locator qmi handle
+ * @servreg_client:	servreg_notifier qmi handle
+ * @servloc_addr:	socket addr of @servloc_client
+ * @servreg_addr:	socket addr of @servreg_client
+ * @lookups:		list of lookup requests
+ * @servloc_list:	list of get domain requests to servreg_locator service
+ * @servreg_list:	list of new messages from servreg_notifer services
+ * @servdel_list:	list of del messages from servreg_notifer services
+ * @indack_list:	list of qmi indications from servreg_notifier services
+ * @list_lock:		lock for modifications of lists
+ * @locator_available:	completion variable to track servreg_locator service
+ * @servloc_work:	work for handling lookup requests
+ * @servreg_work:	work for registering with servreg_notifier service
+ * @servdel_work:	work for notifying PD down service on del server
+ * @indack_work:	work for acking the qmi indications
+ * @servreg_wq:		work queue to post @servreg_work and @servdel_work on
+ * @indack_wq:		work queue to post @indack_work on
+ * @status:		callback to inform the client on PD service state change
+ */
+struct pdr_handle {
+	struct qmi_handle servloc_client;
+	struct qmi_handle servreg_client;
+
+	struct sockaddr_qrtr servloc_addr;
+	struct sockaddr_qrtr servreg_addr;
+
+	struct list_head lookups;
+	struct list_head servloc_list;
+	struct list_head servreg_list;
+	struct list_head servdel_list;
+	struct list_head indack_list;
+
+	/* control access to pdr lists */
+	struct mutex list_lock;
+
+	struct completion locator_available;
+
+	struct work_struct servloc_work;
+	struct work_struct servreg_work;
+	struct work_struct servdel_work;
+	struct work_struct indack_work;
+
+	struct workqueue_struct *servreg_wq;
+	struct workqueue_struct *indack_wq;
+
+	int (*status)(struct pdr_handle *pdr, struct pdr_service *pds);
+};
+
+int pdr_handle_init(struct pdr_handle *pdr, int (*status)(struct pdr_handle *pdr, struct pdr_service *pds));
+int pdr_add_lookup(struct pdr_handle *pdr, const char *service_name, const char *service_path);
+int pdr_restart_pd(struct pdr_handle *pdr, const char *service_path);
+void pdr_handle_release(struct pdr_handle *pdr);
+
+#endif
diff --git a/include/linux/soc/qcom/qmi.h b/include/linux/soc/qcom/qmi.h
index 5efa2b67fa557..e712f94b89fcc 100644
--- a/include/linux/soc/qcom/qmi.h
+++ b/include/linux/soc/qcom/qmi.h
@@ -88,6 +88,7 @@ struct qmi_elem_info {
 #define QMI_ERR_CLIENT_IDS_EXHAUSTED_V01	5
 #define QMI_ERR_INVALID_ID_V01			41
 #define QMI_ERR_ENCODING_V01			58
+#define QMI_ERR_DISABLED_V01                    69
 #define QMI_ERR_INCOMPATIBLE_STATE_V01		90
 #define QMI_ERR_NOT_SUPPORTED_V01		94
 
-- 
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