+/*
+ * All DSP power state transitions are initiated by the driver.
+ * If the requested state change fails, the error is simply returned.
+ * Further state transitions are attempted only when the set_power_save() op
+ * is called again either because of a new IPC sent to the DSP or
+ * during system suspend/resume.
+ */
+int hda_dsp_set_power_state(struct snd_sof_dev *sdev,
+ const struct sof_dsp_power_state *target_state)
+{
+ int ret = 0;
+
+ /* Nothing to do if the DSP is already in the requested state */
+ if (target_state->state == sdev->dsp_power_state.state &&
+ target_state->substate == sdev->dsp_power_state.substate)
+ return 0;
+
+ switch (target_state->state) {
+ case SOF_DSP_PM_D0:
+ ret = hda_dsp_set_D0_state(sdev, target_state);
+ break;
+ case SOF_DSP_PM_D3:
+ /* The only allowed transition is: D0I0 -> D3 */
+ if (sdev->dsp_power_state.state == SOF_DSP_PM_D0 &&
+ sdev->dsp_power_state.substate == SOF_HDA_DSP_PM_D0I0)
+ break;
+
+ dev_err(sdev->dev,
+ "error: transition from %d to %d not allowed\n",
+ sdev->dsp_power_state.state, target_state->state);
+ return -EINVAL;
+ default:
+ dev_err(sdev->dev, "error: target state unsupported %d\n",
+ target_state->state);
+ return -EINVAL;
+ }
+ if (ret < 0) {
+ dev_err(sdev->dev,
+ "failed to set requested target DSP state %d substate %d\n",
+ target_state->state, target_state->substate);
+ return ret;
+ }
+
+ sdev->dsp_power_state = *target_state;
+ dev_dbg(sdev->dev, "New DSP state %d substate %d\n",
+ target_state->state, target_state->substate);
+ return ret;
+}
+
+/*
+ * Audio DSP states may transform as below:-
+ *
+ * D0I3 compatible stream
+ * Runtime +---------------------+ opened only, timeout
+ * suspend | +--------------------+
+ * +------------+ D0(active) | |
+ * | | <---------------+ |
+ * | +--------> | | |
+ * | |Runtime +--^--+---------^--+--+ The last | |
+ * | |resume | | | | opened D0I3 | |
+ * | | | | | | compatible | |
+ * | | resume| | | | stream closed | |
+ * | | from | | D3 | | | |
+ * | | D3 | |suspend | | d0i3 | |
+ * | | | | | |suspend | |
+ * | | | | | | | |
+ * | | | | | | | |
+ * +-v---+-----------+--v-------+ | | +------+----v----+
+ * | | | +-----------> |
+ * | D3 (suspended) | | | D0I3 +-----+
+ * | | +--------------+ | |
+ * | | resume from | | |
+ * +-------------------^--------+ d0i3 suspend +----------------+ |
+ * | |
+ * | D3 suspend |
+ * +------------------------------------------------+
+ *
+ * d0i3_suspend = s0_suspend && D0I3 stream opened,
+ * D3 suspend = !d0i3_suspend,
+ */
+