ASoC: SOF: Move DSP power state transitions to platform-specific ops

The DSP device substates such as D0I0/D0I3
are platform-specific. Therefore, the d0_substate
field of struct snd_sof_dev is replaced
with the dsp_power_state field which represents the current
state of the DSP. This field holds both the device state
and the platform-specific substate values.

With the DSP device substates being platform-specific,
the DSP power state transitions need to be performed in
the platform-specific suspend/resume ops as well.

In order to achieve this, the ops signature has to be
modified to pass the target device state as an
argument. The target substate will be determined by
the platform-specific ops before performing the transition.
For example, in the case of the system suspending to S0IX,
the top-level SOF device suspend callback needs to
only determine if the DSP will be entering
D3 or remain in D0. The target substate in case the device
needs to remain in D0 (D0I0 or D0I3) will be determined
by the platform-specific suspend op.

With the addition of the extended set of power states for the DSP,
the set_power_state op for HDA platforms has to be extended
to handle only the appropriate state transitions. So, the
implementation for the Intel HDA platforms is also modified.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200129220726.31792-6-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

2 files changed, 213 insertions, 20 deletions

diff --git a/sound/soc/sof/intel/hda-dsp.c b/sound/soc/sof/intel/hda-dsp.c
index fddf2c48904f..8c00e128a7b0 100644
--- a/sound/soc/sof/intel/hda-dsp.c
+++ b/sound/soc/sof/intel/hda-dsp.c
@@ -338,13 +338,10 @@ static int hda_dsp_send_pm_gate_ipc(struct snd_sof_dev *sdev, u32 flags)
 				  sizeof(pm_gate), &reply, sizeof(reply));
 }
 
-int hda_dsp_set_power_state(struct snd_sof_dev *sdev,
-			    enum sof_d0_substate d0_substate)
+static int hda_dsp_update_d0i3c_register(struct snd_sof_dev *sdev, u8 value)
 {
 	struct hdac_bus *bus = sof_to_bus(sdev);
-	u32 flags;
 	int ret;
-	u8 value;
 
 	/* Write to D0I3C after Command-In-Progress bit is cleared */
 	ret = hda_dsp_wait_d0i3c_done(sdev);
@@ -354,7 +351,6 @@ int hda_dsp_set_power_state(struct snd_sof_dev *sdev,
 	}
 
 	/* Update D0I3C register */
-	value = d0_substate == SOF_DSP_D0I3 ? SOF_HDA_VS_D0I3C_I3 : 0;
 	snd_hdac_chip_updateb(bus, VS_D0I3C, SOF_HDA_VS_D0I3C_I3, value);
 
 	/* Wait for cmd in progress to be cleared before exiting the function */
@@ -367,20 +363,160 @@ int hda_dsp_set_power_state(struct snd_sof_dev *sdev,
 	dev_vdbg(bus->dev, "D0I3C updated, register = 0x%x\n",
 		 snd_hdac_chip_readb(bus, VS_D0I3C));
 
-	if (d0_substate == SOF_DSP_D0I0)
-		flags = HDA_PM_PPG;/* prevent power gating in D0 */
-	else
-		flags = HDA_PM_NO_DMA_TRACE;/* disable DMA trace in D0I3*/
+	return 0;
+}
 
-	/* sending pm_gate IPC */
-	ret = hda_dsp_send_pm_gate_ipc(sdev, flags);
+static int hda_dsp_set_D0_state(struct snd_sof_dev *sdev,
+				const struct sof_dsp_power_state *target_state)
+{
+	u32 flags = 0;
+	int ret;
+	u8 value = 0;
+
+	/*
+	 * Sanity check for illegal state transitions
+	 * The only allowed transitions are:
+	 * 1. D3 -> D0I0
+	 * 2. D0I0 -> D0I3
+	 * 3. D0I3 -> D0I0
+	 */
+	switch (sdev->dsp_power_state.state) {
+	case SOF_DSP_PM_D0:
+		/* Follow the sequence below for D0 substate transitions */
+		break;
+	case SOF_DSP_PM_D3:
+		/* Follow regular flow for D3 -> D0 transition */
+		return 0;
+	default:
+		dev_err(sdev->dev, "error: transition from %d to %d not allowed\n",
+			sdev->dsp_power_state.state, target_state->state);
+		return -EINVAL;
+	}
+
+	/* Set flags and register value for D0 target substate */
+	if (target_state->substate == SOF_HDA_DSP_PM_D0I3) {
+		value = SOF_HDA_VS_D0I3C_I3;
+
+		/* disable DMA trace in D0I3 */
+		flags = HDA_PM_NO_DMA_TRACE;
+	} else {
+		/* prevent power gating in D0I0 */
+		flags = HDA_PM_PPG;
+	}
+
+	/* update D0I3C register */
+	ret = hda_dsp_update_d0i3c_register(sdev, value);
 	if (ret < 0)
+		return ret;
+
+	/*
+	 * Notify the DSP of the state change.
+	 * If this IPC fails, revert the D0I3C register update in order
+	 * to prevent partial state change.
+	 */
+	ret = hda_dsp_send_pm_gate_ipc(sdev, flags);
+	if (ret < 0) {
 		dev_err(sdev->dev,
 			"error: PM_GATE ipc error %d\n", ret);
+		goto revert;
+	}
+
+	return ret;
+
+revert:
+	/* fallback to the previous register value */
+	value = value ? 0 : SOF_HDA_VS_D0I3C_I3;
+
+	/*
+	 * This can fail but return the IPC error to signal that
+	 * the state change failed.
+	 */
+	hda_dsp_update_d0i3c_register(sdev, value);
 
 	return ret;
 }
 
+/*
+ * 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,
+ */
+
 static int hda_suspend(struct snd_sof_dev *sdev, bool runtime_suspend)
 {
 	struct sof_intel_hda_dev *hda = sdev->pdata->hw_pdata;
@@ -480,8 +616,22 @@ int hda_dsp_resume(struct snd_sof_dev *sdev)
 {
 	struct sof_intel_hda_dev *hda = sdev->pdata->hw_pdata;
 	struct pci_dev *pci = to_pci_dev(sdev->dev);
+	const struct sof_dsp_power_state target_state = {
+		.state = SOF_DSP_PM_D0,
+		.substate = SOF_HDA_DSP_PM_D0I0,
+	};
+	int ret;
+
+	/* resume from D0I3 */
+	if (sdev->dsp_power_state.state == SOF_DSP_PM_D0) {
+		/* Set DSP power state */
+		ret = hda_dsp_set_power_state(sdev, &target_state);
+		if (ret < 0) {
+			dev_err(sdev->dev, "error: setting dsp state %d substate %d\n",
+				target_state.state, target_state.substate);
+			return ret;
+		}
 
-	if (sdev->system_suspend_target == SOF_SUSPEND_S0IX) {
 		/* restore L1SEN bit */
 		if (hda->l1_support_changed)
 			snd_sof_dsp_update_bits(sdev, HDA_DSP_HDA_BAR,
@@ -495,13 +645,27 @@ int hda_dsp_resume(struct snd_sof_dev *sdev)
 	}
 
 	/* init hda controller. DSP cores will be powered up during fw boot */
-	return hda_resume(sdev, false);
+	ret = hda_resume(sdev, false);
+	if (ret < 0)
+		return ret;
+
+	hda_dsp_set_power_state(sdev, &target_state);
+	return ret;
 }
 
 int hda_dsp_runtime_resume(struct snd_sof_dev *sdev)
 {
+	const struct sof_dsp_power_state target_state = {
+		.state = SOF_DSP_PM_D0,
+	};
+	int ret;
+
 	/* init hda controller. DSP cores will be powered up during fw boot */
-	return hda_resume(sdev, true);
+	ret = hda_resume(sdev, true);
+	if (ret < 0)
+		return ret;
+
+	return hda_dsp_set_power_state(sdev, &target_state);
 }
 
 int hda_dsp_runtime_idle(struct snd_sof_dev *sdev)
@@ -519,18 +683,41 @@ int hda_dsp_runtime_idle(struct snd_sof_dev *sdev)
 
 int hda_dsp_runtime_suspend(struct snd_sof_dev *sdev)
 {
+	const struct sof_dsp_power_state target_state = {
+		.state = SOF_DSP_PM_D3,
+	};
+	int ret;
+
 	/* stop hda controller and power dsp off */
-	return hda_suspend(sdev, true);
+	ret = hda_suspend(sdev, true);
+	if (ret < 0)
+		return ret;
+
+	return hda_dsp_set_power_state(sdev, &target_state);
 }
 
-int hda_dsp_suspend(struct snd_sof_dev *sdev)
+int hda_dsp_suspend(struct snd_sof_dev *sdev, u32 target_state)
 {
 	struct sof_intel_hda_dev *hda = sdev->pdata->hw_pdata;
 	struct hdac_bus *bus = sof_to_bus(sdev);
 	struct pci_dev *pci = to_pci_dev(sdev->dev);
+	const struct sof_dsp_power_state target_dsp_state = {
+		.state = target_state,
+		.substate = target_state == SOF_DSP_PM_D0 ?
+				SOF_HDA_DSP_PM_D0I3 : 0,
+	};
 	int ret;
 
-	if (sdev->system_suspend_target == SOF_SUSPEND_S0IX) {
+	if (target_state == SOF_DSP_PM_D0) {
+		/* Set DSP power state */
+		ret = hda_dsp_set_power_state(sdev, &target_dsp_state);
+		if (ret < 0) {
+			dev_err(sdev->dev, "error: setting dsp state %d substate %d\n",
+				target_dsp_state.state,
+				target_dsp_state.substate);
+			return ret;
+		}
+
 		/* enable L1SEN to make sure the system can enter S0Ix */
 		hda->l1_support_changed =
 			snd_sof_dsp_update_bits(sdev, HDA_DSP_HDA_BAR,
@@ -551,7 +738,7 @@ int hda_dsp_suspend(struct snd_sof_dev *sdev)
 		return ret;
 	}
 
-	return 0;
+	return hda_dsp_set_power_state(sdev, &target_dsp_state);
 }
 
 int hda_dsp_set_hw_params_upon_resume(struct snd_sof_dev *sdev)
diff --git a/sound/soc/sof/intel/hda.h b/sound/soc/sof/intel/hda.h
index 6191d9192fae..02c2a7eadb1b 100644
--- a/sound/soc/sof/intel/hda.h
+++ b/sound/soc/sof/intel/hda.h
@@ -392,6 +392,12 @@ struct sof_intel_dsp_bdl {
 #define SOF_HDA_PLAYBACK		0
 #define SOF_HDA_CAPTURE			1
 
+/* HDA DSP D0 substate */
+enum sof_hda_D0_substate {
+	SOF_HDA_DSP_PM_D0I0,	/* default D0 substate */
+	SOF_HDA_DSP_PM_D0I3,	/* low power D0 substate */
+};
+
 /* represents DSP HDA controller frontend - i.e. host facing control */
 struct sof_intel_hda_dev {
 
@@ -469,9 +475,9 @@ void hda_dsp_ipc_int_enable(struct snd_sof_dev *sdev);
 void hda_dsp_ipc_int_disable(struct snd_sof_dev *sdev);
 
 int hda_dsp_set_power_state(struct snd_sof_dev *sdev,
-			    enum sof_d0_substate d0_substate);
+			    const struct sof_dsp_power_state *target_state);
 
-int hda_dsp_suspend(struct snd_sof_dev *sdev);
+int hda_dsp_suspend(struct snd_sof_dev *sdev, u32 target_state);
 int hda_dsp_resume(struct snd_sof_dev *sdev);
 int hda_dsp_runtime_suspend(struct snd_sof_dev *sdev);
 int hda_dsp_runtime_resume(struct snd_sof_dev *sdev);