accel/ivpu/40xx: Capture D0i3 entry host and device timestamps

The driver needs to capture the D0i3 entry timestamp to
calculate D0i3 residency time.

The D0i3 residency time and the VPU timestamp are passed
to the firmware at D0i3 exit (warm boot).
Signed-off-by: Andrzej Kacprowski <andrzej.kacprowski@linux.intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231028133415.1169975-8-stanislaw.gruszka@linux.intel.com

drivers/accel/ivpu/ivpu_hw_40xx.c

@@ -879,10 +879,18 @@ static bool ivpu_hw_40xx_is_idle(struct ivpu_device *vdev)
 	       REG_TEST_FLD(VPU_40XX_BUTTRESS_VPU_STATUS, IDLE, val);
 }
 
+static void ivpu_hw_40xx_save_d0i3_entry_timestamp(struct ivpu_device *vdev)
+{
+	vdev->hw->d0i3_entry_host_ts = ktime_get_boottime();
+	vdev->hw->d0i3_entry_vpu_ts = REGV_RD64(VPU_40XX_CPU_SS_TIM_PERF_EXT_FREE_CNT);
+}
+
 static int ivpu_hw_40xx_power_down(struct ivpu_device *vdev)
 {
 	int ret = 0;
 
+	ivpu_hw_40xx_save_d0i3_entry_timestamp(vdev);
+
 	if (!ivpu_hw_40xx_is_idle(vdev) && ivpu_hw_40xx_reset(vdev))
 		ivpu_warn(vdev, "Failed to reset the VPU\n");