core: nds32: add task_wait_event_mask() function to nds32 core

[task]
1. Copy task_wait_event_mask() function of cortex-m0.
[system]
2. Include host_command.h for host_command_pd_request_hibernate().
[i2c]
3. Update i2c handler to use task_wait_event_mask.

Signed-off-by: Dino Li <dino.li@ite.com.tw>

BRANCH=none
BUG=chromium:435611,chromium:435612
TEST=1. console commands: i2cscan, i2cxfer, and battery.

Change-Id: If5bb4407460d28c0b021ab133ca4b635ff7bc3c9
Reviewed-on: https://chromium-review.googlesource.com/320440
Commit-Ready: Dino Li <dino.li@ite.com.tw>
Tested-by: Dino Li <dino.li@ite.com.tw>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

3 files changed, 32 insertions, 4 deletions

diff --git a/chip/it83xx/i2c.c b/chip/it83xx/i2c.c
index bc10a5970f..fe516bb41f 100644
--- a/chip/it83xx/i2c.c
+++ b/chip/it83xx/i2c.c
@@ -410,7 +410,8 @@ int chip_i2c_xfer(int port, int slave_addr, const uint8_t *out, int out_size,
 	}
 	/* Start transaction */
 	i2c_transaction(port);
-	events = task_wait_event(pd->timeout_us);
+	/* Wait for transfer complete or timeout */
+	events = task_wait_event_mask(TASK_EVENT_I2C_IDLE, pd->timeout_us);
 	/* disable i2c interrupt */
 	task_disable_irq(i2c_ctrl_regs[port].irq);
 	pd->task_waiting = TASK_ID_INVALID;
diff --git a/chip/it83xx/system.c b/chip/it83xx/system.c
index 6019c5f41b..90e234ce86 100644
--- a/chip/it83xx/system.c
+++ b/chip/it83xx/system.c
@@ -9,6 +9,7 @@
 #include "cpu.h"
 #include "ec2i_chip.h"
 #include "flash.h"
+#include "host_command.h"
 #include "registers.h"
 #include "system.h"
 #include "task.h"
diff --git a/core/nds32/task.c b/core/nds32/task.c
index b34e9e9f50..4be65ac913 100644
--- a/core/nds32/task.c
+++ b/core/nds32/task.c
@@ -450,6 +450,34 @@ uint32_t task_wait_event(int timeout_us)
 	return __wait_evt(timeout_us, TASK_ID_IDLE);
 }
 
+uint32_t task_wait_event_mask(uint32_t event_mask, int timeout_us)
+{
+	uint64_t deadline = get_time().val + timeout_us;
+	uint32_t events = 0;
+	int time_remaining_us = timeout_us;
+
+	/* Add the timer event to the mask so we can indicate a timeout */
+	event_mask |= TASK_EVENT_TIMER;
+
+	while (!(events & event_mask)) {
+		/* Collect events to re-post later */
+		events |= __wait_evt(time_remaining_us, TASK_ID_IDLE);
+
+		time_remaining_us = deadline - get_time().val;
+		if (timeout_us > 0 && time_remaining_us <= 0) {
+			/* Ensure we return a TIMER event if we timeout */
+			events |= TASK_EVENT_TIMER;
+			break;
+		}
+	}
+
+	/* Re-post any other events collected */
+	if (events & ~event_mask)
+		atomic_or(&current_task->events, events & ~event_mask);
+
+	return events & event_mask;
+}
+
 uint32_t get_int_mask(void)
 {
 	uint32_t ret;
@@ -577,9 +605,7 @@ void mutex_lock(struct mutex *mtx)
 			/* end of critical section : re-enable interrupts */
 			interrupt_enable();
 			/* Sleep waiting for our turn */
-			/* TODO(crbug.com/435612, crbug.com/435611)
-			 * This discards any pending events! */
-			task_wait_event(0);
+			task_wait_event_mask(TASK_EVENT_MUTEX, 0);
 			/* re-enter critical section */
 			interrupt_disable();
 		}