TISCI PM Low Power Mode API Documentation¶
Note
This document is applicable to AM62x, AM62Ax and AM62Px devices.
Introduction¶
This document describes the TISCI API for entering different low power modes supported by the SOC.
Supported low power modes¶
TISCI_MSG_VALUE_SLEEP_MODE_DEEP_SLEEP 0x0U
Sleep mode in which complete SOC except the wakeup domain is turned off.
TISCI_MSG_VALUE_SLEEP_MODE_MCU_ONLY 0x1U
Sleep mode in which complete SOC except the wakeup and MCU domain is turned off.
TISCI_MSG_VALUE_SLEEP_MODE_IO_ONLY_PLUS_DDR 0x2U
Sleep mode in which complete SOC except the DDR memory and CAN IOs is turned off.
TISCI_MSG_VALUE_SLEEP_MODE_PARTIAL_IO 0x3U
Sleep mode in which complete SOC except the CAN IOs is turned off.
TISCI_MSG_VALUE_SLEEP_MODE_STANDBY 0x4U
Sleep mode in which software is in low power mode but the hardware remains on.
| Low power mode | Supported by |
|---|---|
| DEEP_SLEEP | am62x, am62ax, am62px |
| MCU_ONLY | am62x, am62ax, am62px |
| IO_ONLY_PLUS_DDR | am62ax, am62px |
| PARTIAL_IO | am62x, am62ax, am62px |
| STANDBY | None |
Intermediate mode values¶
TISCI_MSG_VALUE_SLEEP_MODE_DM_MANAGED 0xFDU
Value passed to request device manager for low power mode selection.
TISCI_MSG_VALUE_SLEEP_MODE_NOT_SELECTED 0xFEU
Value returned if device manager has not yet selected the low power mode.
TISCI_MSG_VALUE_SLEEP_MODE_INVALID 0xFFU
Value returned if low power mode entered is invalid.
Device configuration and control APIs¶
| TISCI Message ID | Message Name |
|---|---|
| 0x0300 | TISCI_MSG_PREPARE_SLEEP |
| 0x0301 | TISCI_MSG_ENTER_SLEEP |
| 0x0306 | TISCI_MSG_LPM_WAKE_REASON |
| 0x0307 | TISCI_MSG_SET_IO_ISOLATION |
| 0x0308 | TISCI_MSG_MIN_CONTEXT_RESTORE |
| 0x0309 | TISCI_MSG_LPM_SET_DEVICE_CONSTRAINT |
| 0x030A | TISCI_MSG_LPM_SET_LATENCY_CONSTRAINT |
| 0x030B | TISCI_MSG_LPM_GET_DEVICE_CONSTRAINT |
| 0x030C | TISCI_MSG_LPM_GET_LATENCY_CONSTRAINT |
| 0x030D | TISCI_MSG_LPM_GET_NEXT_SYS_MODE |
| 0x030E | TISCI_MSG_LPM_GET_NEXT_HOST_STATE |
Macros Used in this Document¶
TISCI_MSG_VALUE_IO_ENABLE 1U
Used by TISCI_MSG_SET_IO_ISOLATION to enable IO isolation
TISCI_MSG_VALUE_IO_DISABLE 0U
Used by TISCI_MSG_SET_IO_ISOLATION to disable IO isolation
TISCI_MSG_VALUE_HOST_STATE_ON 1U
Used by TISCI_MSG_GET_NEXT_HOST_STATE to return remote core’s state as on
TISCI_MSG_VALUE_HOST_STATE_OFF 0U
Used by TISCI_MSG_GET_NEXT_HOST_STATE to return remote core’s state as off
TISCI_MSG_VALUE_HOST_STATE_INVALID 0xFFU
Used by TISCI_MSG_GET_NEXT_HOST_STATE to return remote core’s state as invalid
TISCI_MSG_VALUE_STATE_SET 1U
Used by set and get constraints APIs to set/get constraint for device/latency
TISCI_MSG_VALUE_STATE_CLEAR 0U
Used by set and get constraints APIs to clear/get constraint for device/latency
TISCI_MSG_VALUE_LPM_WAKE_PIN_INVALID 0xFFU
Used by TISCI_MSG_LPM_WAKE_REASON to return wake pin number as invalid
TISCI_MSG_PREPARE_SLEEP¶
Objective¶
Prepare the SOC for entering into a low power mode.
Usage¶
| Message Type | Normal |
| Secure Queue Only? | No |
TISCI Message ID¶
TISCI_MSG_PREPARE_SLEEP (0x0300U)
Message Data Structures¶
struct tisci_msg_prepare_sleep_req
Request for TISCI_MSG_PREPARE_SLEEP.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| mode | u8 | Low power mode to enter. |
| ctx_lo | u32 | Low 32-bits of physical pointer to address to use for context save. |
| ctx_hi | u32 | High 32-bits of physical pointer to address to use for context save. |
| debug_flags | u32 | Flags that can be set to halt the sequence during suspend or resume to allow JTAG connection and debug. |
This message is used as the first step of entering a low power mode. It allows configurable information, including which state to enter to be easily shared from the application, as this is a non-secure message and therefore can be sent by anyone. Notes: Mode is defined as one of TISCI_MSG_VALUE_SLEEP_MODE_x macros. Mode parameter should be equal to partial IO low power mode for partial IO mode entry. In this mode, ctx_lo and ctx_hi are unused. There is no requirement of “carve out” in DDR. Mode parameter should be equal to intermediate value “DM managed” if mode selection logic has to be applied. In this case, ctx_lo and ctx_hi are reserved for internal use (DM application should allocate “carve out” for LPM) For mode value not equal to “DM managed” or partial IO, ctx_lo and ctx_hi should be a reserved memory region as decided on by the HLOS. This region should be a carve out in DDR and valid for use with DMA. Otherwise there are no constraints on this memory. An encrypted blob will be placed here and only a valid blob can be decrypted and authenticated, which eliminates risk of tampering.
struct tisci_msg_prepare_sleep_resp
Response for TISCI_MSG_PREPARE_SLEEP.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
TISCI_MSG_ENTER_SLEEP¶
Objective¶
Enter into a low power mode.
Note
Before calling the TISCI_MSG_ENTER_SLEEP, TISCI_MSG_PREPARE_SLEEP should be called to prepare for the low power mode.
Usage¶
| Message Type | Normal |
| Secure Queue Only? | Yes |
TISCI Message ID¶
TISCI_MSG_ENTER_SLEEP (0x0301U)
Message Data Structures¶
struct tisci_msg_enter_sleep_req
Request for TISCI_MSG_ENTER_SLEEP.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| mode | u8 | Low power mode to enter. |
| proc_id | u8 | Processor id to be used for restoring boot vector and debug status upon resume. |
| core_resume_lo | u32 | Low 32-bits of physical pointer to address for core to begin execution upon resume. |
| core_resume_hi | u32 | High 32-bits of physical pointer to address for core to begin execution upon resume. |
This message is to be sent after TISCI_MSG_PREPARE_SLEEP and actually triggers entry into the previously selected low power mode.
struct tisci_msg_enter_sleep_resp
Response for TISCI_MSG_ENTER_SLEEP.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| status | u32 | Value that gives information about what happened during LPM cycle. |
TISCI_MSG_LPM_WAKE_REASON¶
Objective¶
Get the last entered low power mode, wake up source and pin (if applicable) that woke the soc.
Wake up sources¶
| Wake Up Source | Source ID |
|---|---|
| WKUP_I2C0 | 0x00 |
| WKUP_UART0 | 0x10 |
| MCU_GPIO0 | 0x20 |
| WKUP_ICEMELTER0 | 0x30 |
| WKUP_TIMER0 | 0x40 |
| WKUP_TIMER1 | 0x41 |
| WKUP_RTC0 | 0x50 |
| RESET | 0x60 |
| USB0 | 0x70 |
| USB1 | 0x71 |
| MAIN_IO | 0x80 |
| MCU_IO | 0x81 |
| CAN_IO | 0x82 |
| MCU_IPC | 0x90 |
| INVALID | 0xFF |
Wake up pin¶
Refer to the Pad Configuration PADCONFIG Registers in Registers chapter in the TRM to get information about pad number.
Note
In case of wakeup event on multiple pins simultaneously/concurrently, the smaller padcfg number will be returned.
Usage¶
| Message Type | Normal |
| Secure Queue Only? | No |
TISCI Message ID¶
TISCI_MSG_LPM_WAKE_REASON (0x0306U)
Message Data Structures¶
struct tisci_msg_lpm_wake_reason_req
Request for TISCI_MSG_LPM_WAKE_REASON.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
This message is used to query the wake up source from low power mode.
struct tisci_msg_lpm_wake_reason_resp
Response for TISCI_MSG_LPM_WAKE_REASON.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| wake_source | u32 | The wake up source that woke soc from LPM. |
| wake_timestamp | u64 | Timestamp at which soc woke. |
| wake_pin | u8 | The pin that has triggered wake up. |
| mode | u8 | The last entered low power mode. |
| rsvd_0 | u32 | Reserved for future use. |
| rsvd_1 | u32 | Reserved for future use. |
TISCI_MSG_SET_IO_ISOLATION¶
Objective¶
Enable and disable IO isolation
Usage¶
| Message Type | Normal |
| Secure Queue Only? | No |
TISCI Message ID¶
TISCI_MSG_SET_IO_ISOLATION (0x0307U)
Message Data Structures¶
struct tisci_msg_set_io_isolation_req
Request for TISCI_MSG_SET_IO_ISOLATION.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| state | u8 | The desired state of the IO isolation. |
This message is used to enable/disable IO isolation for low power modes.
struct tisci_msg_set_io_isolation_resp
Response for TISCI_MSG_SET_IO_ISOLATION.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
TISCI_MSG_MIN_CONTEXT_RESTORE¶
Objective¶
Restore the minimal context saved during lpm entry.
Note
This message is registered only if IO Only Plus DDR low power mode exit is detected from MMR read.
Usage¶
| Message Type | Normal |
| Secure Queue Only? | Yes |
TISCI Message ID¶
TISCI_MSG_MIN_CONTEXT_RESTORE (0x0308U)
Message Data Structures¶
struct tisci_msg_min_context_restore_req
Request for TISCI_MSG_MIN_CONTEXT_RESTORE.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| ctx_lo | u32 | Low 32-bits of physical pointer to address to use for context restore. |
| ctx_hi | u32 | High 32-bits of physical pointer to address to use for context restore. |
This message is sent from R5 SPL to TIFS to indicate that DDR is active and TIFS can restore the minimal context from the address provided in the ctx_lo and ctx_hi parameters. This response assumes DDR has been fully restored by R5 SPL before it is sent.
struct tisci_msg_min_context_restore_resp
Response for TISCI_MSG_MIN_CONTEXT_RESTORE.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
This response is sent from the TIFS to the R5 SPL to indicate that now standard firmware can be executed. This response is sent after DDR firewalls have been fully restored by TIFS.
TISCI_MSG_LPM_SET_DEVICE_CONSTRAINT¶
Objective¶
Any device can set a constraint on the low power mode that the SoC can enter.
Note
By setting a constraint, the device ensures that it will not be powered off or reset in the selected mode. Setting constraint on a device does not ensure that the device will be functional in the selected low power mode. Exception: Setting constraint on DDR ensures that DDR will be functional in the selected low power mode. All constraints will be auto cleared at every resume cycle.
Usage¶
| Message Type | Normal |
| Secure Queue Only? | No |
TISCI Message ID¶
TISCI_MSG_LPM_SET_DEVICE_CONSTRAINT (0x0309U)
Message Data Structures¶
struct tisci_msg_lpm_set_device_constraint_req
Request for TISCI_MSG_LPM_SET_DEVICE_CONSTRAINT.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| id | u32 | Device ID of device on which constraint has to be set/cleared. |
| state | u8 | The desired state of constraint: set or clear. |
| rsvd_0 | u32 | Reserved for future use. |
| rsvd_1 | u32 | Reserved for future use. |
This message is used by host to set constraint on a device. This can be sent anytime after boot before prepare sleep message and after current low power mode is exited. Any device can set a constraint on the low power mode that the SoC can enter. It allows configurable information to be easily shared from the application, as this is a non-secure message and therefore can be sent by anyone. By setting a constraint, the device ensures that it will not be powered off or reset in the selected mode. Notes: Access Restriction: Exclusivity flag of Device will be honored for setting constraint. If some other host has exclusive rights on this device, NAK will be returned. Clearing of constraints can be done irrespective of exclusivity.
struct tisci_msg_lpm_set_device_constraint_resp
Response for TISCI_MSG_LPM_SET_DEVICE_CONSTRAINT.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
TISCI_MSG_LPM_SET_LATENCY_CONSTRAINT¶
Objective¶
Any host can set a constraint on the low power mode that the SoC can enter.
Latency Table¶
| Low power mode | Minimum (ms) | Maximum (ms) |
|---|---|---|
| DEEPEST | 251 | X |
| DEEP_SLEEP | 101 | 250 |
| MCU_ONLY | 10 | 100 |
In the above table, DEEPEST is DEEP_SLEEP for am62x and IO_ONLY_PLUS_DDR for am62ax and am62px.
Note
By setting a wakeup latency constraint, the host ensures that the resume time from selected low power mode will be less than the constraint value. For deepest low power mode, there is no upper limit (maximum value) for latency. All constraints will be auto cleared at every resume cycle.
Usage¶
| Message Type | Normal |
| Secure Queue Only? | No |
TISCI Message ID¶
TISCI_MSG_LPM_SET_LATENCY_CONSTRAINT (0x030AU)
Message Data Structures¶
struct tisci_msg_lpm_set_latency_constraint_req
Request for TISCI_MSG_LPM_SET_LATENCY_CONSTRAINT.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| resume_latency | u16 | The maximum acceptable latency to wake up from low power mode in milliseconds. The deeper the state, the higher the latency. |
| state | u8 | The desired state of constraint: set or clear. |
| rsvd | u32 | Reserved for future use. |
This message is used by host to set latency for waking up from low power mode. This can be sent anytime after boot before prepare sleep message and after current low power mode is exited. Any host can set a constraint on the low power mode that the SoC can enter. It allows configurable information to be easily shared from the application, as this is a non-secure message and therefore can be sent by anyone. By setting a wakeup latency constraint, the host ensures that the resume time from selected low power mode will be less than the constraint value.
struct tisci_msg_lpm_set_latency_constraint_resp
Response for TISCI_MSG_LPM_SET_LATENCY_CONSTRAINT.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
TISCI_MSG_LPM_GET_DEVICE_CONSTRAINT¶
Objective¶
Get the constraints set by a host on a device.
Usage¶
| Message Type | Normal |
| Secure Queue Only? | No |
TISCI Message ID¶
TISCI_MSG_LPM_GET_DEVICE_CONSTRAINT (0x030BU)
Message Data Structures¶
struct tisci_msg_lpm_get_device_constraint_req
Request for TISCI_MSG_LPM_GET_DEVICE_CONSTRAINT.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| id | u32 | Device ID of device for which constraint value is requested. |
This message is used by host to get constraints that it has put on a device.
struct tisci_msg_lpm_get_device_constraint_resp
Response for TISCI_MSG_LPM_GET_DEVICE_CONSTRAINT.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| state | u8 | The returned state of constraint: set or clear. |
TISCI_MSG_LPM_GET_LATENCY_CONSTRAINT¶
Objective¶
Get the low power mode resume latency value set by a host.
Usage¶
| Message Type | Normal |
| Secure Queue Only? | No |
TISCI Message ID¶
TISCI_MSG_LPM_GET_LATENCY_CONSTRAINT (0x030CU)
Message Data Structures¶
struct tisci_msg_lpm_get_latency_constraint_req
Request for TISCI_MSG_LPM_GET_LATENCY_CONSTRAINT.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
This message is used by the host to get the resume latency it set for waking up from low power mode.
struct tisci_msg_lpm_get_latency_constraint_resp
Response for TISCI_MSG_LPM_GET_LATENCY_CONSTRAINT.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| resume_latency | u16 | The maximum acceptable latency for waking up from low power mode in milliseconds. The deeper the state, the higher the latency. |
| state | u8 | The returned state of constraint: set or clear. |
TISCI_MSG_LPM_GET_NEXT_SYS_MODE¶
Objective¶
Return the next (upcoming) power state of the system. It can be one of the following system modes.
System modes¶
| System mode | Mode ID |
|---|---|
| DEEP_SLEEP | 0x00 |
| MCU_ONLY | 0x01 |
| IO_ONLY_PLUS_DDR | 0x02 |
| PARTIAL_IO | 0x03 |
| STANDBY | 0x04 |
| NOT_SELECTED | 0xFE |
Usage¶
| Message Type | Normal |
| Secure Queue Only? | No |
TISCI Message ID¶
TISCI_MSG_LPM_GET_NEXT_SYS_MODE (0x030DU)
Message Data Structures¶
struct tisci_msg_lpm_get_next_sys_mode_req
Request for TISCI_MSG_LPM_GET_NEXT_SYS_MODE.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
This message is used to enquire DM for selected system wide low power mode.
struct tisci_msg_lpm_get_next_sys_mode_resp
Response for TISCI_MSG_LPM_GET_NEXT_SYS_MODE.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| mode | u8 | The selected system wide low power mode. |
Note: If the mode selection is not yet locked, this API returns “not selected” mode.
TISCI_MSG_LPM_GET_NEXT_HOST_STATE¶
Objective¶
Return the next (upcoming) power state of the requesting host.
Host states¶
| Host state | State ID |
|---|---|
| OFF | 0x00 |
| ON | 0x01 |
| INVALID | 0xFF |
Usage¶
| Message Type | Normal |
| Secure Queue Only? | No |
TISCI Message ID¶
TISCI_MSG_LPM_GET_NEXT_HOST_STATE (0x030EU)
Message Data Structures¶
struct tisci_msg_lpm_get_next_host_state_req
Request for TISCI_MSG_GET_LPM_NEXT_HOST_STATE.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
This message is used by host to enquire DM for its expected state in current low power mode selection - ON or OFF.
struct tisci_msg_lpm_get_next_host_state_resp
Response for TISCI_MSG_LPM_GET_NEXT_HOST_STATE.
| Parameter | Type | Description |
|---|---|---|
| hdr | struct tisci_header | TISCI header to provide ACK/NAK flags to the host. |
| state | u8 | The expected state of host in selected low power mode. |
Note: If the mode selection is not yet locked, this API returns invalid state.