[v6] usb: typec: tcpm: Migrate workqueue to RT priority for processing events

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 3ef37202ee37..dc4d18630f4f 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -8,8 +8,10 @@ 
 #include <linux/completion.h>
 #include <linux/debugfs.h>
 #include <linux/device.h>
+#include <linux/hrtimer.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
+#include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/power_supply.h>
@@ -28,7 +30,8 @@ 
 #include <linux/usb/role.h>
 #include <linux/usb/tcpm.h>
 #include <linux/usb/typec_altmode.h>
-#include <linux/workqueue.h>
+
+#include <uapi/linux/sched/types.h>
 
 #define FOREACH_STATE(S)			\
 	S(INVALID_STATE),			\
@@ -203,7 +206,7 @@  struct tcpm_port {
 	struct device *dev;
 
 	struct mutex lock;		/* tcpm state machine lock */
-	struct workqueue_struct *wq;
+	struct kthread_worker *wq;
 
 	struct typec_capability typec_caps;
 	struct typec_port *typec_port;
@@ -247,15 +250,17 @@  struct tcpm_port {
 	enum tcpm_state prev_state;
 	enum tcpm_state state;
 	enum tcpm_state delayed_state;
-	unsigned long delayed_runtime;
+	ktime_t delayed_runtime;
 	unsigned long delay_ms;
 
 	spinlock_t pd_event_lock;
 	u32 pd_events;
 
-	struct work_struct event_work;
-	struct delayed_work state_machine;
-	struct delayed_work vdm_state_machine;
+	struct kthread_work event_work;
+	struct hrtimer state_machine_timer;
+	struct kthread_work state_machine;
+	struct hrtimer vdm_state_machine_timer;
+	struct kthread_work vdm_state_machine;
 	bool state_machine_running;
 
 	struct completion tx_complete;
@@ -340,7 +345,7 @@  struct tcpm_port {
 };
 
 struct pd_rx_event {
-	struct work_struct work;
+	struct kthread_work work;
 	struct tcpm_port *port;
 	struct pd_message msg;
 };
@@ -914,6 +919,27 @@  static int tcpm_pd_send_sink_caps(struct tcpm_port *port)
 	return tcpm_pd_transmit(port, TCPC_TX_SOP, &msg);
 }
 
+static void mod_tcpm_delayed_work(struct tcpm_port *port, unsigned int delay_ms)
+{
+	if (delay_ms) {
+		hrtimer_start(&port->state_machine_timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
+	} else {
+		hrtimer_cancel(&port->state_machine_timer);
+		kthread_queue_work(port->wq, &port->state_machine);
+	}
+}
+
+static void mod_vdm_delayed_work(struct tcpm_port *port, unsigned int delay_ms)
+{
+	if (delay_ms) {
+		hrtimer_start(&port->vdm_state_machine_timer, ms_to_ktime(delay_ms),
+			      HRTIMER_MODE_REL);
+	} else {
+		hrtimer_cancel(&port->vdm_state_machine_timer);
+		kthread_queue_work(port->wq, &port->vdm_state_machine);
+	}
+}
+
 static void tcpm_set_state(struct tcpm_port *port, enum tcpm_state state,
 			   unsigned int delay_ms)
 {
@@ -922,9 +948,8 @@  static void tcpm_set_state(struct tcpm_port *port, enum tcpm_state state,
 			 tcpm_states[port->state], tcpm_states[state],
 			 delay_ms);
 		port->delayed_state = state;
-		mod_delayed_work(port->wq, &port->state_machine,
-				 msecs_to_jiffies(delay_ms));
-		port->delayed_runtime = jiffies + msecs_to_jiffies(delay_ms);
+		mod_tcpm_delayed_work(port, delay_ms);
+		port->delayed_runtime = ktime_add(ktime_get(), ms_to_ktime(delay_ms));
 		port->delay_ms = delay_ms;
 	} else {
 		tcpm_log(port, "state change %s -> %s",
@@ -939,7 +964,7 @@  static void tcpm_set_state(struct tcpm_port *port, enum tcpm_state state,
 		 * machine.
 		 */
 		if (!port->state_machine_running)
-			mod_delayed_work(port->wq, &port->state_machine, 0);
+			mod_tcpm_delayed_work(port, 0);
 	}
 }
 
@@ -960,7 +985,7 @@  static void tcpm_queue_message(struct tcpm_port *port,
 			       enum pd_msg_request message)
 {
 	port->queued_message = message;
-	mod_delayed_work(port->wq, &port->state_machine, 0);
+	mod_tcpm_delayed_work(port, 0);
 }
 
 /*
@@ -981,7 +1006,7 @@  static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header,
 	port->vdm_retries = 0;
 	port->vdm_state = VDM_STATE_READY;
 
-	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
+	mod_vdm_delayed_work(port, 0);
 }
 
 static void tcpm_queue_vdm_unlocked(struct tcpm_port *port, const u32 header,
@@ -1244,8 +1269,7 @@  static void tcpm_handle_vdm_request(struct tcpm_port *port,
 			port->vdm_state = VDM_STATE_WAIT_RSP_BUSY;
 			port->vdo_retry = (p[0] & ~VDO_CMDT_MASK) |
 				CMDT_INIT;
-			mod_delayed_work(port->wq, &port->vdm_state_machine,
-					 msecs_to_jiffies(PD_T_VDM_BUSY));
+			mod_vdm_delayed_work(port, PD_T_VDM_BUSY);
 			return;
 		}
 		port->vdm_state = VDM_STATE_DONE;
@@ -1390,8 +1414,7 @@  static void vdm_run_state_machine(struct tcpm_port *port)
 			port->vdm_retries = 0;
 			port->vdm_state = VDM_STATE_BUSY;
 			timeout = vdm_ready_timeout(port->vdo_data[0]);
-			mod_delayed_work(port->wq, &port->vdm_state_machine,
-					 timeout);
+			mod_vdm_delayed_work(port, timeout);
 		}
 		break;
 	case VDM_STATE_WAIT_RSP_BUSY:
@@ -1420,10 +1443,9 @@  static void vdm_run_state_machine(struct tcpm_port *port)
 	}
 }
 
-static void vdm_state_machine_work(struct work_struct *work)
+static void vdm_state_machine_work(struct kthread_work *work)
 {
-	struct tcpm_port *port = container_of(work, struct tcpm_port,
-					      vdm_state_machine.work);
+	struct tcpm_port *port = container_of(work, struct tcpm_port, vdm_state_machine);
 	enum vdm_states prev_state;
 
 	mutex_lock(&port->lock);
@@ -1591,6 +1613,7 @@  static int tcpm_altmode_vdm(struct typec_altmode *altmode,
 	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
 
 	tcpm_queue_vdm_unlocked(port, header, data, count - 1);
+
 	return 0;
 }
 
@@ -2005,7 +2028,7 @@  static void tcpm_pd_ext_msg_request(struct tcpm_port *port,
 	}
 }
 
-static void tcpm_pd_rx_handler(struct work_struct *work)
+static void tcpm_pd_rx_handler(struct kthread_work *work)
 {
 	struct pd_rx_event *event = container_of(work,
 						 struct pd_rx_event, work);
@@ -2067,10 +2090,10 @@  void tcpm_pd_receive(struct tcpm_port *port, const struct pd_message *msg)
 	if (!event)
 		return;
 
-	INIT_WORK(&event->work, tcpm_pd_rx_handler);
+	kthread_init_work(&event->work, tcpm_pd_rx_handler);
 	event->port = port;
 	memcpy(&event->msg, msg, sizeof(*msg));
-	queue_work(port->wq, &event->work);
+	kthread_queue_work(port->wq, &event->work);
 }
 EXPORT_SYMBOL_GPL(tcpm_pd_receive);
 
@@ -2123,9 +2146,9 @@  static bool tcpm_send_queued_message(struct tcpm_port *port)
 	} while (port->queued_message != PD_MSG_NONE);
 
 	if (port->delayed_state != INVALID_STATE) {
-		if (time_is_after_jiffies(port->delayed_runtime)) {
-			mod_delayed_work(port->wq, &port->state_machine,
-					 port->delayed_runtime - jiffies);
+		if (ktime_after(port->delayed_runtime, ktime_get())) {
+			mod_tcpm_delayed_work(port, ktime_to_ms(ktime_sub(port->delayed_runtime,
+									  ktime_get())));
 			return true;
 		}
 		port->delayed_state = INVALID_STATE;
@@ -3258,10 +3281,9 @@  static void run_state_machine(struct tcpm_port *port)
 	case SNK_DISCOVERY_DEBOUNCE_DONE:
 		if (!tcpm_port_is_disconnected(port) &&
 		    tcpm_port_is_sink(port) &&
-		    time_is_after_jiffies(port->delayed_runtime)) {
+		    ktime_after(port->delayed_runtime, ktime_get())) {
 			tcpm_set_state(port, SNK_DISCOVERY,
-				       jiffies_to_msecs(port->delayed_runtime -
-							jiffies));
+				       ktime_to_ms(ktime_sub(port->delayed_runtime, ktime_get())));
 			break;
 		}
 		tcpm_set_state(port, unattached_state(port), 0);
@@ -3656,10 +3678,9 @@  static void run_state_machine(struct tcpm_port *port)
 	}
 }
 
-static void tcpm_state_machine_work(struct work_struct *work)
+static void tcpm_state_machine_work(struct kthread_work *work)
 {
-	struct tcpm_port *port = container_of(work, struct tcpm_port,
-					      state_machine.work);
+	struct tcpm_port *port = container_of(work, struct tcpm_port, state_machine);
 	enum tcpm_state prev_state;
 
 	mutex_lock(&port->lock);
@@ -4019,7 +4040,7 @@  static void _tcpm_pd_hard_reset(struct tcpm_port *port)
 		       0);
 }
 
-static void tcpm_pd_event_handler(struct work_struct *work)
+static void tcpm_pd_event_handler(struct kthread_work *work)
 {
 	struct tcpm_port *port = container_of(work, struct tcpm_port,
 					      event_work);
@@ -4060,7 +4081,7 @@  void tcpm_cc_change(struct tcpm_port *port)
 	spin_lock(&port->pd_event_lock);
 	port->pd_events |= TCPM_CC_EVENT;
 	spin_unlock(&port->pd_event_lock);
-	queue_work(port->wq, &port->event_work);
+	kthread_queue_work(port->wq, &port->event_work);
 }
 EXPORT_SYMBOL_GPL(tcpm_cc_change);
 
@@ -4069,7 +4090,7 @@  void tcpm_vbus_change(struct tcpm_port *port)
 	spin_lock(&port->pd_event_lock);
 	port->pd_events |= TCPM_VBUS_EVENT;
 	spin_unlock(&port->pd_event_lock);
-	queue_work(port->wq, &port->event_work);
+	kthread_queue_work(port->wq, &port->event_work);
 }
 EXPORT_SYMBOL_GPL(tcpm_vbus_change);
 
@@ -4078,7 +4099,7 @@  void tcpm_pd_hard_reset(struct tcpm_port *port)
 	spin_lock(&port->pd_event_lock);
 	port->pd_events = TCPM_RESET_EVENT;
 	spin_unlock(&port->pd_event_lock);
-	queue_work(port->wq, &port->event_work);
+	kthread_queue_work(port->wq, &port->event_work);
 }
 EXPORT_SYMBOL_GPL(tcpm_pd_hard_reset);
 
@@ -4786,6 +4807,22 @@  static int devm_tcpm_psy_register(struct tcpm_port *port)
 	return PTR_ERR_OR_ZERO(port->psy);
 }
 
+static enum hrtimer_restart state_machine_timer_handler(struct hrtimer *timer)
+{
+	struct tcpm_port *port = container_of(timer, struct tcpm_port, state_machine_timer);
+
+	kthread_queue_work(port->wq, &port->state_machine);
+	return HRTIMER_NORESTART;
+}
+
+static enum hrtimer_restart vdm_state_machine_timer_handler(struct hrtimer *timer)
+{
+	struct tcpm_port *port = container_of(timer, struct tcpm_port, vdm_state_machine_timer);
+
+	kthread_queue_work(port->wq, &port->vdm_state_machine);
+	return HRTIMER_NORESTART;
+}
+
 struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
 {
 	struct tcpm_port *port;
@@ -4807,12 +4844,18 @@  struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
 	mutex_init(&port->lock);
 	mutex_init(&port->swap_lock);
 
-	port->wq = create_singlethread_workqueue(dev_name(dev));
-	if (!port->wq)
-		return ERR_PTR(-ENOMEM);
-	INIT_DELAYED_WORK(&port->state_machine, tcpm_state_machine_work);
-	INIT_DELAYED_WORK(&port->vdm_state_machine, vdm_state_machine_work);
-	INIT_WORK(&port->event_work, tcpm_pd_event_handler);
+	port->wq = kthread_create_worker(0, dev_name(dev));
+	if (IS_ERR(port->wq))
+		return ERR_CAST(port->wq);
+	sched_set_fifo(port->wq->task);
+
+	kthread_init_work(&port->state_machine, tcpm_state_machine_work);
+	kthread_init_work(&port->vdm_state_machine, vdm_state_machine_work);
+	kthread_init_work(&port->event_work, tcpm_pd_event_handler);
+	hrtimer_init(&port->state_machine_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	port->state_machine_timer.function = state_machine_timer_handler;
+	hrtimer_init(&port->vdm_state_machine_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	port->vdm_state_machine_timer.function = vdm_state_machine_timer_handler;
 
 	spin_lock_init(&port->pd_event_lock);
 
@@ -4864,7 +4907,7 @@  struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
 	usb_role_switch_put(port->role_sw);
 out_destroy_wq:
 	tcpm_debugfs_exit(port);
-	destroy_workqueue(port->wq);
+	kthread_destroy_worker(port->wq);
 	return ERR_PTR(err);
 }
 EXPORT_SYMBOL_GPL(tcpm_register_port);
@@ -4879,7 +4922,7 @@  void tcpm_unregister_port(struct tcpm_port *port)
 	typec_unregister_port(port->typec_port);
 	usb_role_switch_put(port->role_sw);
 	tcpm_debugfs_exit(port);
-	destroy_workqueue(port->wq);
+	kthread_destroy_worker(port->wq);
 }
 EXPORT_SYMBOL_GPL(tcpm_unregister_port);