ASoC: Intel: avs: D0ix power state support

Audio DSP device supports D0 substates in form of D0ix, allowing for
preserving more power even when device is still considered active (D0).
When entered, certain domains which are not being currently used become
power gated. Entering and leaving D0ix is a complex process and differs
between firmware generations.

Conditions that disallow D0i3 and require immediate D0i0 transition
include but may not be limited to: IPC traffic, firmware tracing and
SRAM I/O. To make D0ix toggling sane, delay D0i3 transition and refresh
the timer each time an IPC is requested.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220516101116.190192-9-cezary.rojewski@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 120 insertions, 1 deletions

diff --git a/sound/soc/intel/avs/ipc.c b/sound/soc/intel/avs/ipc.c
index feb900ba1db9..2cf4cb4f0c56 100644
--- a/sound/soc/intel/avs/ipc.c
+++ b/sound/soc/intel/avs/ipc.c
@@ -13,6 +13,82 @@
 #include "registers.h"
 
 #define AVS_IPC_TIMEOUT_MS	300
+#define AVS_D0IX_DELAY_MS	300
+
+static int
+avs_dsp_set_d0ix(struct avs_dev *adev, bool enable)
+{
+	struct avs_ipc *ipc = adev->ipc;
+	int ret;
+
+	/* Is transition required? */
+	if (ipc->in_d0ix == enable)
+		return 0;
+
+	ret = avs_dsp_op(adev, set_d0ix, enable);
+	if (ret) {
+		/* Prevent further d0ix attempts on conscious IPC failure. */
+		if (ret == -AVS_EIPC)
+			atomic_inc(&ipc->d0ix_disable_depth);
+
+		ipc->in_d0ix = false;
+		return ret;
+	}
+
+	ipc->in_d0ix = enable;
+	return 0;
+}
+
+static void avs_dsp_schedule_d0ix(struct avs_dev *adev, struct avs_ipc_msg *tx)
+{
+	if (atomic_read(&adev->ipc->d0ix_disable_depth))
+		return;
+
+	mod_delayed_work(system_power_efficient_wq, &adev->ipc->d0ix_work,
+			 msecs_to_jiffies(AVS_D0IX_DELAY_MS));
+}
+
+static void avs_dsp_d0ix_work(struct work_struct *work)
+{
+	struct avs_ipc *ipc = container_of(work, struct avs_ipc, d0ix_work.work);
+
+	avs_dsp_set_d0ix(to_avs_dev(ipc->dev), true);
+}
+
+static int avs_dsp_wake_d0i0(struct avs_dev *adev, struct avs_ipc_msg *tx)
+{
+	struct avs_ipc *ipc = adev->ipc;
+
+	if (!atomic_read(&ipc->d0ix_disable_depth)) {
+		cancel_delayed_work_sync(&ipc->d0ix_work);
+		return avs_dsp_set_d0ix(adev, false);
+	}
+
+	return 0;
+}
+
+int avs_dsp_disable_d0ix(struct avs_dev *adev)
+{
+	struct avs_ipc *ipc = adev->ipc;
+
+	/* Prevent PG only on the first disable. */
+	if (atomic_add_return(1, &ipc->d0ix_disable_depth) == 1) {
+		cancel_delayed_work_sync(&ipc->d0ix_work);
+		return avs_dsp_set_d0ix(adev, false);
+	}
+
+	return 0;
+}
+
+int avs_dsp_enable_d0ix(struct avs_dev *adev)
+{
+	struct avs_ipc *ipc = adev->ipc;
+
+	if (atomic_dec_and_test(&ipc->d0ix_disable_depth))
+		queue_delayed_work(system_power_efficient_wq, &ipc->d0ix_work,
+				   msecs_to_jiffies(AVS_D0IX_DELAY_MS));
+	return 0;
+}
 
 static void avs_dsp_recovery(struct avs_dev *adev)
 {
@@ -88,6 +164,8 @@ static void avs_dsp_exception_caught(struct avs_dev *adev, union avs_notify_msg
 
 	dev_crit(adev->dev, "communication severed, rebooting dsp..\n");
 
+	cancel_delayed_work_sync(&ipc->d0ix_work);
+	ipc->in_d0ix = false;
 	/* Re-enabled on recovery completion. */
 	pm_runtime_disable(adev->dev);
 
@@ -393,10 +471,35 @@ exit:
 	return ret;
 }
 
+static int avs_dsp_send_msg_sequence(struct avs_dev *adev, struct avs_ipc_msg *request,
+				     struct avs_ipc_msg *reply, int timeout, bool wake_d0i0,
+				     bool schedule_d0ix)
+{
+	int ret;
+
+	if (wake_d0i0) {
+		ret = avs_dsp_wake_d0i0(adev, request);
+		if (ret)
+			return ret;
+	}
+
+	ret = avs_dsp_do_send_msg(adev, request, reply, timeout);
+	if (ret)
+		return ret;
+
+	if (schedule_d0ix)
+		avs_dsp_schedule_d0ix(adev, request);
+
+	return 0;
+}
+
 int avs_dsp_send_msg_timeout(struct avs_dev *adev, struct avs_ipc_msg *request,
 			     struct avs_ipc_msg *reply, int timeout)
 {
-	return avs_dsp_do_send_msg(adev, request, reply, timeout);
+	bool wake_d0i0 = avs_dsp_op(adev, d0ix_toggle, request, true);
+	bool schedule_d0ix = avs_dsp_op(adev, d0ix_toggle, request, false);
+
+	return avs_dsp_send_msg_sequence(adev, request, reply, timeout, wake_d0i0, schedule_d0ix);
 }
 
 int avs_dsp_send_msg(struct avs_dev *adev, struct avs_ipc_msg *request,
@@ -405,6 +508,19 @@ int avs_dsp_send_msg(struct avs_dev *adev, struct avs_ipc_msg *request,
 	return avs_dsp_send_msg_timeout(adev, request, reply, adev->ipc->default_timeout_ms);
 }
 
+int avs_dsp_send_pm_msg_timeout(struct avs_dev *adev, struct avs_ipc_msg *request,
+				struct avs_ipc_msg *reply, int timeout, bool wake_d0i0)
+{
+	return avs_dsp_send_msg_sequence(adev, request, reply, timeout, wake_d0i0, false);
+}
+
+int avs_dsp_send_pm_msg(struct avs_dev *adev, struct avs_ipc_msg *request,
+			struct avs_ipc_msg *reply, bool wake_d0i0)
+{
+	return avs_dsp_send_pm_msg_timeout(adev, request, reply, adev->ipc->default_timeout_ms,
+					   wake_d0i0);
+}
+
 static int avs_dsp_do_send_rom_msg(struct avs_dev *adev, struct avs_ipc_msg *request, int timeout)
 {
 	struct avs_ipc *ipc = adev->ipc;
@@ -465,6 +581,7 @@ int avs_ipc_init(struct avs_ipc *ipc, struct device *dev)
 	ipc->ready = false;
 	ipc->default_timeout_ms = AVS_IPC_TIMEOUT_MS;
 	INIT_WORK(&ipc->recovery_work, avs_dsp_recovery_work);
+	INIT_DELAYED_WORK(&ipc->d0ix_work, avs_dsp_d0ix_work);
 	init_completion(&ipc->done_completion);
 	init_completion(&ipc->busy_completion);
 	spin_lock_init(&ipc->rx_lock);
@@ -477,4 +594,6 @@ void avs_ipc_block(struct avs_ipc *ipc)
 {
 	ipc->ready = false;
 	cancel_work_sync(&ipc->recovery_work);
+	cancel_delayed_work_sync(&ipc->d0ix_work);
+	ipc->in_d0ix = false;
 }