lib: sbi_timer: Add support for timer events

Currently, the sbi_timer only supports timer events configured via
SBI calls. Introduce struct sbi_timer_event and related functions
to allow configuring timer events from any part of OpenSBI.

Signed-off-by: Anup Patel <[email protected]>
Reviewed-by: Nicholas Piggin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Anup Patel <[email protected]>

1 files changed, 62 insertions, 3 deletions

diff --git a/include/sbi/sbi_timer.h b/include/sbi/sbi_timer.h
index 2e1a7879..914a5f12 100644
--- a/include/sbi/sbi_timer.h
+++ b/include/sbi/sbi_timer.h
@@ -10,7 +10,60 @@
 #ifndef __SBI_TIMER_H__
 #define __SBI_TIMER_H__
 
-#include <sbi/sbi_types.h>
+#include <sbi/sbi_list.h>
+
+/** Timer event re-start details */
+struct sbi_timer_event_restart {
+	/** Flag indicating whether event re-start is required */
+	bool required;
+	/** Next time stamp for event if re-start is required */
+	u64 next_event;
+};
+
+/** Timer event abstraction */
+struct sbi_timer_event {
+	/** List head for per-HART event list (Internal) */
+	struct sbi_dlist head;
+
+	/** Hart on which the event is started / running (Internal) */
+	int hart_index;
+
+	/** Time stamp when the event expires (Internal) */
+	u64 time_stamp;
+
+	/**
+	 * Event callback to be called upon expiry.
+	 *
+	 * If the callback wants to re-start the event then
+	 * it must update the event re-start details.
+	 *
+	 * NOTE: This will be called with the per-HART timer
+	 * event list lock held.
+	 */
+	void (*callback)(struct sbi_timer_event *ev,
+			 struct sbi_timer_event_restart *restart);
+
+	/**
+	 * Event cleanup to be called upon sbi_timer_exit()
+	 *
+	 * NOTE: This will be called with per-HART timer
+	 * event list lock held.
+	 */
+	void (*cleanup)(struct sbi_timer_event *ev);
+
+	/** Event specific private data */
+	void *priv;
+};
+
+#define SBI_INIT_TIMER_EVENT(__ptr, __callback, __cleanup, __priv)	\
+do {									\
+	SBI_INIT_LIST_HEAD(&(__ptr)->head);				\
+	(__ptr)->hart_index = -1;					\
+	(__ptr)->time_stamp = 0;					\
+	(__ptr)->callback = (__callback); 				\
+	(__ptr)->cleanup = (__cleanup); 				\
+	(__ptr)->priv = (__priv); 					\
+} while (0)
 
 /** Timer hardware device */
 struct sbi_timer_device {
@@ -86,8 +139,14 @@ void sbi_timer_set_delta(ulong delta);
 void sbi_timer_set_delta_upper(ulong delta_upper);
 #endif
 
-/** Start timer event for current HART */
-void sbi_timer_event_start(u64 next_event);
+/** Start timer event on current HART */
+void sbi_timer_event_start(struct sbi_timer_event *ev, u64 next_event);
+
+/** Stop timer event on current HART */
+void sbi_timer_event_stop(struct sbi_timer_event *ev);
+
+/** Start supervisor timer event on current HART */
+void sbi_timer_smode_event_start(u64 next_event);
 
 /** Process timer event for current HART */
 void sbi_timer_process(void);