arch: fw: sof-zephyr dmic io driver

dmic io driver architecture chapter

Signed-off-by: Michal Wasko <[email protected]>

Author: mwasko

architectures/firmware/sof-zephyr/rtos_layer/io_drivers/dmic/dmic_driver.rst

@@ -0,0 +1,44 @@
+.. _dmic_driver:
+
+DMIC IO Driver
+##############
+
+.. uml:: images/dmic_diagram.pu
+   :caption: DMIC IO Driver overview
+
+Gateway Initialization
+**********************
+
+.. uml:: images/dmic_gateway_init.pu
+   :caption: DMIC Input Gateway Initialization
+
+DMIC HW is initialized as follows:
+
+  1. Mute microphones.
+  2. Enable clock on microphones (also enable CIC and FIRs).
+  3. Wait for clock stabilization (SoC defined delay).
+  4. Unmute microphones using a curved ramp until the DC offset is gone and
+     replaced with the live stream.
+
+Configuration BLOB
+******************
+
+DMIC IO Driver is prepared for the configuration BLOB to come in context of any
+instance of the DmicInput at any time. The configuration may be rejected if the
+current state of PDM controllers and FIFOs is inappropriate. Accepting the
+configuration does not always mean that it is immediately programmed to the HW.
+The configuration is global, so when sent by an instance of DmicInput while
+another instance is already running it is just compared with already programmed
+data for the sake of consistency.
+
+Gateway Release
+***************
+
+.. uml:: images/dmic_gateway_release.pu
+   :caption: DMIC Input Gateway Release
+
+State Transitions
+*****************
+
+.. uml:: images/dmic_gateway_state_transitions.pu
+   :caption: DMIC Input Gateway State Transition

architectures/firmware/sof-zephyr/rtos_layer/io_drivers/dmic/images/dmic_diagram.pu

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+@startuml
+
+hide methods
+hide attributes
+
+component Zephyr {
+	class DmicDriver
+	interface dai_dmic_ops
+	interface dai_driver_api
+}
+
+component MPP {
+	interface Gateway
+
+	interface IoDriver
+	class DmicManager
+	class DmicInput
+}
+
+DmicDriver -up- dai_dmic_ops
+
+dai_dmic_ops -left-|> dai_driver_api : implements
+
+DmicManager -up- IoDriver
+DmicManager -left-> DmicInput : manages
+DmicInput -up- Gateway
+DmicInput -down-> dai_dmic_ops : calls
+DmicDriver --* DmicInput
+
+@enduml

architectures/firmware/sof-zephyr/rtos_layer/io_drivers/dmic/images/dmic_gateway_init.pu

@@ -0,0 +1,23 @@
+@startuml
+
+participant "DMIC Manager" as dmic_manager
+participant "Zephyr PM Subsystem" as zephyr_pm
+participant "DMIC Driver" as dmic_driver
+
+-> dmic_manager : gateway_allocate()
+	activate dmic_manager
+	dmic_manager -> zephyr_pm : pm_runtime_device_get (dmic)
+
+		activate zephyr_pm
+		zephyr_pm -> zephyr_pm : increase usage count
+		opt if usage == 1
+		zephyr_pm -> dmic_driver : pm_device_resume
+			activate dmic_driver
+			return
+		end
+		return
+
+	deactivate dmic_manager
+<-- dmic_manager
+
+@enduml

architectures/firmware/sof-zephyr/rtos_layer/io_drivers/dmic/images/dmic_gateway_release.pu

@@ -0,0 +1,23 @@
+@startuml
+
+participant "DMIC Manager" as dmic_manager
+participant "Zephyr PM Subsystem" as zephyr_pm
+participant "DMIC Driver" as dmic_driver
+
+-> dmic_manager : gateway_release()
+	activate dmic_manager
+	dmic_manager -> zephyr_pm : pm_runtime_device_put (dmic)
+
+		activate zephyr_pm
+		zephyr_pm -> zephyr_pm : decrease usage count
+		opt if usage == 0
+		zephyr_pm -> dmic_driver : pm_device_suspend
+			activate dmic_driver
+			return
+		end
+		return
+
+	deactivate dmic_manager
+<-- dmic_manager
+
+@enduml

architectures/firmware/sof-zephyr/rtos_layer/io_drivers/dmic/images/dmic_gateway_state_transitions.pu

@@ -0,0 +1,19 @@
+
+participant "Dmic Input\nGateway" as dmic_input
+participant "DMA" as dma
+
+== Dmic Input : STOPPED ==
+
+-> dmic_input : STOPPED
+	dmic_input -> dma : stop()
+
+== Dmic Input : PAUSED ==
+
+-> dmic_input : PAUSED
+	dmic_input -> dma : init_transfer()
+	dmic_input -> dma : pause()
+
+== Dmic Input : RUNNING ==
+
+-> dmic_input : RUNNING
+	dmic_input -> dma : start()

architectures/firmware/sof-zephyr/rtos_layer/io_drivers/index.rst

@@ -28,3 +28,4 @@ Drivers
 
    hda/hda_driver
    i2s/i2s_driver
+   dmic/dmic_driver