[PATCH v8 0/3] firmware: ti_sci: Introduce system suspend support

[PATCH v8 0/3] firmware: ti_sci: Introduce system suspend support

[Markus Schneider-Pargmann]

Abstract
********

This series introduces necessary ti_sci driver functionality to support
various Suspend-to-RAM modes on TI AM62 family of devices. These Low
Power Modes include Deep Sleep and MCU Only as described in section
"6.2.4 Power Modes" of the AM62x Technical Reference Manual [0].

Summary
*******

This series is a restructuring and rebase of the patch series by
Dave Gerlach [1] and Dhruva Gole [2]. It applies on top of Linux
6.11-rc1.

The kernel triggers entry to Low Power Mode through the mem suspend
transition with the following:

* At the bootloader stage, one is expected to package the TIFS stub
  which then gets pulled into the Tightly coupled memory of the Device Mgr
  (DM) R5 when it starts up. If using U-Boot, then it requires tispl.bin
  to contain the TIFS stub. Refer to ti-u-boot patch [3] for further
  details. The supported firmware version is from TI Processor SDK
  >= 10.00 ie. tag 10.00.04 from ti-linux-firmware [4].

* Use a TF-A binary that supports PSCI_SYSTEM_SUSPEND call. This causes
  system to use PSCI system suspend as last step of mem sleep.

* The firmware requires that the OS sends a TISCI_MSG_PREPARE_SLEEP
  message in order to provide details about suspend, so we must add the
  ability to send this message. We also add the remaining TISCI Low Power
  Mode messages required for inquiring wake reason, enabling I/O
  isolation, and managing LPM constraints as part of a new PM ops. These
  messages are part of the TISCI PM Low Power Mode API [5]. (Patch 1)

* We add support for the TISCI_MSG_QUERY_FW_CAPS message, used to retrieve
  the firmware capabilities of the currently running system firmware [6].
  Sysfw version >= 10.00.04 support LPM_DM_MANAGED capability, where
  Device Mgr firmware now manages which low power mode is chosen. Going
  forward, this is the default configuration supported for TI AM62 family
  of devices. The state chosen by the DM can be influenced by sending
  constraints using the new LPM constraint APIs. (Patch 2)

* Finally, the ti_sci driver must actually send TISCI_MSG_PREPARE_SLEEP
  message to firmware with the above information included, which it
  does during the driver suspend handler when PM_MEM_SUSPEND is the
  determined state being entered. The mode being sent depends on whether
  firmware capabilities have support for LPM_DM_MANAGED feature. Legacy
  firmware or those supporting other modes can extend the mode selection
  logic as needed. (Patch 3)

Testing
*******

This series can for example be tested with a am62a-lp-sk board.

For am62a-lp-sk all usb nodes have to be disabled at the moment (usbss0,
usb0, usbss1 and usb1). There is currently an issue with USB Link Power
Management and turning off the USB device which is being worked on.

Once booted suspend/resume can be tested with rtcwake:
  $ rtcwake -m mem -s 10 -d /dev/rtc0

Make sure /dev/rtc0 corresponds to rtc-ti-k3:
  $ dmesg | grep rtc-ti-k3
  rtc-ti-k3 2b1f0000.rtc: registered as rtc0

Base commit:
************

v6.11-rc1

Changelog:
**********

v8:
- Restructuring of code to include all TISCI PM LPM ops
- Removing malloc related to TIFS Stub as it is managed by DM
- Dropping has_lpm check as suggested by Nishanth
- Using LPM_DM_MANAGED capability for mode selection
- Updating the suspend and resume callback handlers

v7:
- Address Andrew's concerns on SYSFW fw_caps API
- Remove all the unused functions and variables including
  set_io_isolation and wake_reason calls
- use dma_free_attrs
- remove IO isolation related code from linux side,

v6:
- link to v6 [5]
- Loading of FS Stub from linux no longer needed, hence drop that patch,
- Drop 1/6 and 5/6 from the previous series [4].
- Add system suspend resume callbacks which were removed in
commit 9225bcdedf16297a346082e7d23b0e8434aa98ed ("firmware: ti_sci: Use
system_state to determine polling")
- Use IO isolation while putting the system in suspend to RAM

v5:
- Add support (patch 3) for detecting the low power modes (LPM) of the
  FW/SoC with a recently introduced core TISCI_MSG_QUERY_FW_CAPS message.
- Use TISCI_MSG_QUERY_FW_CAPS instead of misusing the
  TISCI_MSG_PREPARE_SLEEP to detect the FW/SoC low power caps (patch 4).
- Take into account the supported LPMs in ti_sci_prepare_system_suspend()
  and handle the case when CONFIG_SUSPEND is not enabled (patch 6) that
  was reported by Roger Quadros and LKP.
- Pick up Rob Herring's "Reviewed-by" tag for the binding patch.

v4:
- Fix checkpacth warnings in patches 2 and 3.
- Drop the links with anchors in patch 2.

v3:
- Fix the compile warnings on 32-bit platforms reported by the kernel
  test robot in patches (3,5).
- Pick up Roger's "Tested-by" tags.

v2:
- Addressed comments received for v1 series [1].
- Updated v1 patch 5 to use pm notifier to avoid firmware loading
  issues.
- Dropped the reserved region requirement and allocate DMA memory
  instead. The reserved region binding patch is also removed.
- Introduce two more TISCI LPM messages that are supported in SysFW.
- Fixes in error handling.

References:
***********

[0] https://www.ti.com/lit/pdf/spruiv7
[1] https://lore.kernel.org/lkml/20220421203659.27853-1-d-gerlach@ti.com
[2] https://lore.kernel.org/lkml/20230804115037.754994-1-d-gole@ti.com
[3] https://git.ti.com/cgit/ti-u-boot/ti-u-boot/commit/?h=ti-u-boot-2023.04&id=91886b68025c7ad121e62d1fc1fa4601eeb736cd
[4] https://git.ti.com/cgit/processor-firmware/ti-linux-firmware/commit/?h=10.00.06&id=193f7d7570583a41ddc50a221e37c32be6be583e
[5] https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/pm/lpm.html
[6] https://downloads.ti.com/tisci/esd/latest/2_tisci_msgs/general/core.html#tisci-msg-query-fw-caps

Dave Gerlach (1):
  firmware: ti_sci: Introduce Power Management Ops

Georgi Vlaev (1):
  firmware: ti_sci: Add support for querying the firmware caps

Vibhore Vardhan (1):
  firmware: ti_sci: Add system suspend and resume call

 drivers/firmware/ti_sci.c              | 438 ++++++++++++++++++++++++-
 drivers/firmware/ti_sci.h              | 137 +++++++-
 include/linux/soc/ti/ti_sci_protocol.h |  46 +++
 3 files changed, 619 insertions(+), 2 deletions(-)

-- 
2.45.2

[PATCH v8 1/3] firmware: ti_sci: Introduce Power Management Ops

[Markus Schneider-Pargmann]

From: Dave Gerlach <d-gerlach@ti.com>

Introduce power management ops supported by the TISCI
Low Power Mode API [1].

1) TISCI_MSG_PREPARE_SLEEP
Prepare the SOC for entering into a low power mode and
provide details to firmware about the state being entered.

2) TISCI_MSG_LPM_WAKE_REASON
Get which wake up source woke the SoC from Low Power Mode.
The wake up source IDs will be common for all K3 platforms.

3) TISCI_MSG_SET_IO_ISOLATION
Control the IO isolation for Low Power Mode.

4) TISCI_MSG_LPM_SET_DEVICE_CONSTRAINT
Set LPM constraint on behalf of a device. By setting a constraint, the
device ensures that it will not be powered off or reset in the selected
mode.

5) TISCI_MSG_LPM_SET_LATENCY_CONSTRAINT
Set LPM resume latency constraint. By setting a constraint, the host
ensures that the resume time from selected mode will be less than the
constraint value.

[1] https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/pm/lpm.html

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
[g-vlaev@ti.com: LPM_WAKE_REASON and IO_ISOLATION support]
Signed-off-by: Georgi Vlaev <g-vlaev@ti.com>
[a-kaur@ti.com: SET_DEVICE_CONSTRAINT support]
Signed-off-by: Akashdeep Kaur <a-kaur@ti.com>
[vibhore@ti.com: SET_LATENCY_CONSTRAINT support]
Signed-off-by: Vibhore Vardhan <vibhore@ti.com>
Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
---
 drivers/firmware/ti_sci.c              | 283 ++++++++++++++++++++++++-
 drivers/firmware/ti_sci.h              | 115 +++++++++-
 include/linux/soc/ti/ti_sci_protocol.h |  46 ++++
 3 files changed, 442 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 160968301b1f..3599aeecef86 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -2,7 +2,7 @@
 /*
  * Texas Instruments System Control Interface Protocol Driver
  *
- * Copyright (C) 2015-2022 Texas Instruments Incorporated - https://www.ti.com/
+ * Copyright (C) 2015-2024 Texas Instruments Incorporated - https://www.ti.com/
  *	Nishanth Menon
  */
 
@@ -1651,6 +1651,284 @@ static int ti_sci_cmd_clk_get_freq(const struct ti_sci_handle *handle,
 	return ret;
 }
 
+/**
+ * ti_sci_cmd_prepare_sleep() - Prepare system for system suspend
+ * @handle:		pointer to TI SCI handle
+ * @mode:		Device identifier
+ * @ctx_lo:		Low part of address for context save
+ * @ctx_hi:		High part of address for context save
+ * @debug_flags:	Debug flags to pass to firmware
+ *
+ * Return: 0 if all went well, else returns appropriate error value.
+ */
+static int ti_sci_cmd_prepare_sleep(const struct ti_sci_handle *handle, u8 mode,
+				    u32 ctx_lo, u32 ctx_hi, u32 debug_flags)
+{
+	struct ti_sci_info *info;
+	struct ti_sci_msg_req_prepare_sleep *req;
+	struct ti_sci_msg_hdr *resp;
+	struct ti_sci_xfer *xfer;
+	struct device *dev;
+	int ret = 0;
+
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	if (!handle)
+		return -EINVAL;
+
+	info = handle_to_ti_sci_info(handle);
+	dev = info->dev;
+
+	xfer = ti_sci_get_one_xfer(info, TI_SCI_MSG_PREPARE_SLEEP,
+				   TI_SCI_FLAG_REQ_ACK_ON_PROCESSED,
+				   sizeof(*req), sizeof(*resp));
+	if (IS_ERR(xfer)) {
+		ret = PTR_ERR(xfer);
+		dev_err(dev, "Message alloc failed(%d)\n", ret);
+		return ret;
+	}
+
+	req = (struct ti_sci_msg_req_prepare_sleep *)xfer->xfer_buf;
+	req->mode = mode;
+	req->ctx_lo = ctx_lo;
+	req->ctx_hi = ctx_hi;
+	req->debug_flags = debug_flags;
+
+	ret = ti_sci_do_xfer(info, xfer);
+	if (ret) {
+		dev_err(dev, "Mbox send fail %d\n", ret);
+		goto fail;
+	}
+
+	resp = (struct ti_sci_msg_hdr *)xfer->xfer_buf;
+
+	ret = ti_sci_is_response_ack(resp) ? 0 : -ENODEV;
+
+fail:
+	ti_sci_put_one_xfer(&info->minfo, xfer);
+
+	return ret;
+}
+
+/**
+ * ti_sci_msg_cmd_lpm_wake_reason() - Get the wakeup source from LPM
+ * @handle:		Pointer to TI SCI handle
+ * @source:		The wakeup source that woke the SoC from LPM
+ * @timestamp:		Timestamp of the wakeup event
+ *
+ * Return: 0 if all went well, else returns appropriate error value.
+ */
+static int ti_sci_msg_cmd_lpm_wake_reason(const struct ti_sci_handle *handle,
+					  u32 *source, u64 *timestamp)
+{
+	struct ti_sci_info *info;
+	struct ti_sci_xfer *xfer;
+	struct ti_sci_msg_resp_lpm_wake_reason *resp;
+	struct device *dev;
+	int ret = 0;
+
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	if (!handle)
+		return -EINVAL;
+
+	info = handle_to_ti_sci_info(handle);
+	dev = info->dev;
+
+	xfer = ti_sci_get_one_xfer(info, TI_SCI_MSG_LPM_WAKE_REASON,
+				   TI_SCI_FLAG_REQ_ACK_ON_PROCESSED,
+				   sizeof(struct ti_sci_msg_hdr),
+				   sizeof(*resp));
+	if (IS_ERR(xfer)) {
+		ret = PTR_ERR(xfer);
+		dev_err(dev, "Message alloc failed(%d)\n", ret);
+		return ret;
+	}
+
+	ret = ti_sci_do_xfer(info, xfer);
+	if (ret) {
+		dev_err(dev, "Mbox send fail %d\n", ret);
+		goto fail;
+	}
+
+	resp = (struct ti_sci_msg_resp_lpm_wake_reason *)xfer->xfer_buf;
+
+	if (!ti_sci_is_response_ack(resp)) {
+		ret = -ENODEV;
+		goto fail;
+	}
+
+	if (source)
+		*source = resp->wake_source;
+	if (timestamp)
+		*timestamp = resp->wake_timestamp;
+
+fail:
+	ti_sci_put_one_xfer(&info->minfo, xfer);
+
+	return ret;
+}
+
+/**
+ * ti_sci_cmd_set_io_isolation() - Enable IO isolation in LPM
+ * @handle:		Pointer to TI SCI handle
+ * @state:		The desired state of the IO isolation
+ *
+ * Return: 0 if all went well, else returns appropriate error value.
+ */
+static int ti_sci_cmd_set_io_isolation(const struct ti_sci_handle *handle,
+				       u8 state)
+{
+	struct ti_sci_info *info;
+	struct ti_sci_msg_req_set_io_isolation *req;
+	struct ti_sci_msg_hdr *resp;
+	struct ti_sci_xfer *xfer;
+	struct device *dev;
+	int ret = 0;
+
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	if (!handle)
+		return -EINVAL;
+
+	info = handle_to_ti_sci_info(handle);
+	dev = info->dev;
+
+	xfer = ti_sci_get_one_xfer(info, TI_SCI_MSG_SET_IO_ISOLATION,
+				   TI_SCI_FLAG_REQ_ACK_ON_PROCESSED,
+				   sizeof(*req), sizeof(*resp));
+	if (IS_ERR(xfer)) {
+		ret = PTR_ERR(xfer);
+		dev_err(dev, "Message alloc failed(%d)\n", ret);
+		return ret;
+	}
+	req = (struct ti_sci_msg_req_set_io_isolation *)xfer->xfer_buf;
+	req->state = state;
+
+	ret = ti_sci_do_xfer(info, xfer);
+	if (ret) {
+		dev_err(dev, "Mbox send fail %d\n", ret);
+		goto fail;
+	}
+
+	resp = (struct ti_sci_msg_hdr *)xfer->xfer_buf;
+
+	ret = ti_sci_is_response_ack(resp) ? 0 : -ENODEV;
+
+fail:
+	ti_sci_put_one_xfer(&info->minfo, xfer);
+
+	return ret;
+}
+
+/**
+ * ti_sci_cmd_set_device_constraint() - Set LPM constraint on behalf of a device
+ * @handle:	pointer to TI SCI handle
+ * @id:	Device identifier
+ * @state:	The desired state of device constraint: set or clear
+ *
+ * Return: 0 if all went well, else returns appropriate error value.
+ */
+static int ti_sci_cmd_set_device_constraint(const struct ti_sci_handle *handle,
+					    u32 id, u8 state)
+{
+	struct ti_sci_info *info;
+	struct ti_sci_msg_req_lpm_set_device_constraint *req;
+	struct ti_sci_msg_hdr *resp;
+	struct ti_sci_xfer *xfer;
+	struct device *dev;
+	int ret = 0;
+
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	if (!handle)
+		return -EINVAL;
+
+	info = handle_to_ti_sci_info(handle);
+	dev = info->dev;
+
+	xfer = ti_sci_get_one_xfer(info, TI_SCI_MSG_LPM_SET_DEVICE_CONSTRAINT,
+				   TI_SCI_FLAG_REQ_ACK_ON_PROCESSED,
+				   sizeof(*req), sizeof(*resp));
+	if (IS_ERR(xfer)) {
+		ret = PTR_ERR(xfer);
+		dev_err(dev, "Message alloc failed(%d)\n", ret);
+		return ret;
+	}
+	req = (struct ti_sci_msg_req_lpm_set_device_constraint *)xfer->xfer_buf;
+	req->id = id;
+	req->state = state;
+
+	ret = ti_sci_do_xfer(info, xfer);
+	if (ret) {
+		dev_err(dev, "Mbox send fail %d\n", ret);
+		goto fail;
+	}
+
+	resp = (struct ti_sci_msg_hdr *)xfer->xfer_buf;
+
+	ret = ti_sci_is_response_ack(resp) ? 0 : -ENODEV;
+
+fail:
+	ti_sci_put_one_xfer(&info->minfo, xfer);
+
+	return ret;
+}
+
+/**
+ * ti_sci_cmd_set_latency_constraint() - Set LPM resume latency constraint
+ * @handle:	pointer to TI SCI handle
+ * @latency:	maximum acceptable latency (in ms) to wake up from LPM
+ * @state:	The desired state of latency constraint: set or clear
+ *
+ * Return: 0 if all went well, else returns appropriate error value.
+ */
+static int ti_sci_cmd_set_latency_constraint(const struct ti_sci_handle *handle,
+					     u16 latency, u8 state)
+{
+	struct ti_sci_info *info;
+	struct ti_sci_msg_req_lpm_set_latency_constraint *req;
+	struct ti_sci_msg_hdr *resp;
+	struct ti_sci_xfer *xfer;
+	struct device *dev;
+	int ret = 0;
+
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	if (!handle)
+		return -EINVAL;
+
+	info = handle_to_ti_sci_info(handle);
+	dev = info->dev;
+
+	xfer = ti_sci_get_one_xfer(info, TI_SCI_MSG_LPM_SET_LATENCY_CONSTRAINT,
+				   TI_SCI_FLAG_REQ_ACK_ON_PROCESSED,
+				   sizeof(*req), sizeof(*resp));
+	if (IS_ERR(xfer)) {
+		ret = PTR_ERR(xfer);
+		dev_err(dev, "Message alloc failed(%d)\n", ret);
+		return ret;
+	}
+	req = (struct ti_sci_msg_req_lpm_set_latency_constraint *)xfer->xfer_buf;
+	req->latency = latency;
+	req->state = state;
+
+	ret = ti_sci_do_xfer(info, xfer);
+	if (ret) {
+		dev_err(dev, "Mbox send fail %d\n", ret);
+		goto fail;
+	}
+
+	resp = (struct ti_sci_msg_hdr *)xfer->xfer_buf;
+
+	ret = ti_sci_is_response_ack(resp) ? 0 : -ENODEV;
+
+fail:
+	ti_sci_put_one_xfer(&info->minfo, xfer);
+
+	return ret;
+}
+
 static int ti_sci_cmd_core_reboot(const struct ti_sci_handle *handle)
 {
 	struct ti_sci_info *info;
@@ -2793,6 +3071,7 @@ static void ti_sci_setup_ops(struct ti_sci_info *info)
 	struct ti_sci_core_ops *core_ops = &ops->core_ops;
 	struct ti_sci_dev_ops *dops = &ops->dev_ops;
 	struct ti_sci_clk_ops *cops = &ops->clk_ops;
+	struct ti_sci_pm_ops *pmops = &ops->pm_ops;
 	struct ti_sci_rm_core_ops *rm_core_ops = &ops->rm_core_ops;
 	struct ti_sci_rm_irq_ops *iops = &ops->rm_irq_ops;
 	struct ti_sci_rm_ringacc_ops *rops = &ops->rm_ring_ops;
@@ -2832,6 +3111,8 @@ static void ti_sci_setup_ops(struct ti_sci_info *info)
 	cops->set_freq = ti_sci_cmd_clk_set_freq;
 	cops->get_freq = ti_sci_cmd_clk_get_freq;
 
+	pmops->lpm_wake_reason = ti_sci_msg_cmd_lpm_wake_reason;
+
 	rm_core_ops->get_range = ti_sci_cmd_get_resource_range;
 	rm_core_ops->get_range_from_shost =
 				ti_sci_cmd_get_resource_range_from_shost;
diff --git a/drivers/firmware/ti_sci.h b/drivers/firmware/ti_sci.h
index 5846c60220f5..424bc192ce3e 100644
--- a/drivers/firmware/ti_sci.h
+++ b/drivers/firmware/ti_sci.h
@@ -6,7 +6,7 @@
  * The system works in a message response protocol
  * See: https://software-dl.ti.com/tisci/esd/latest/index.html for details
  *
- * Copyright (C)  2015-2016 Texas Instruments Incorporated - https://www.ti.com/
+ * Copyright (C)  2015-2024 Texas Instruments Incorporated - https://www.ti.com/
  */
 
 #ifndef __TI_SCI_H
@@ -35,6 +35,13 @@
 #define TI_SCI_MSG_QUERY_CLOCK_FREQ	0x010d
 #define TI_SCI_MSG_GET_CLOCK_FREQ	0x010e
 
+/* Low Power Mode Requests */
+#define TI_SCI_MSG_PREPARE_SLEEP	0x0300
+#define TI_SCI_MSG_LPM_WAKE_REASON	0x0306
+#define TI_SCI_MSG_SET_IO_ISOLATION	0x0307
+#define TI_SCI_MSG_LPM_SET_DEVICE_CONSTRAINT	0x0309
+#define TI_SCI_MSG_LPM_SET_LATENCY_CONSTRAINT	0x030A
+
 /* Resource Management Requests */
 #define TI_SCI_MSG_GET_RESOURCE_RANGE	0x1500
 
@@ -545,6 +552,112 @@ struct ti_sci_msg_resp_get_clock_freq {
 	u64 freq_hz;
 } __packed;
 
+/**
+ * struct tisci_msg_req_prepare_sleep - Request for TISCI_MSG_PREPARE_SLEEP.
+ *
+ * @hdr				TISCI header to provide ACK/NAK flags to the host.
+ * @mode			Low power mode to enter.
+ * @ctx_lo			Low 32-bits of physical pointer to address to use for context save.
+ * @ctx_hi			High 32-bits of physical pointer to address to use for context save.
+ * @debug_flags			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.
+ */
+struct ti_sci_msg_req_prepare_sleep {
+	struct ti_sci_msg_hdr	hdr;
+
+#define TISCI_MSG_VALUE_SLEEP_MODE_DM_MANAGED				0xfd
+	u8			mode;
+	u32			ctx_lo;
+	u32			ctx_hi;
+	u32			debug_flags;
+} __packed;
+
+/**
+ * struct ti_sci_msg_resp_lpm_wake_reason - Response for TI_SCI_MSG_LPM_WAKE_REASON.
+ *
+ * @hdr:		Generic header.
+ * @wake_source:	The wake up source that woke soc from LPM.
+ * @wake_timestamp:	Timestamp at which soc woke.
+ *
+ * Response to a generic message with message type TI_SCI_MSG_LPM_WAKE_REASON,
+ * used to query the wake up source from low power mode.
+ */
+struct ti_sci_msg_resp_lpm_wake_reason {
+	struct ti_sci_msg_hdr hdr;
+	u32 wake_source;
+	u64 wake_timestamp;
+} __packed;
+
+/**
+ * struct tisci_msg_set_io_isolation_req - Request for TI_SCI_MSG_SET_IO_ISOLATION.
+ *
+ * @hdr:	Generic header
+ * @state:	The deseared state of the IO isolation.
+ *
+ * This message is used to enable/disable IO isolation for low power modes.
+ * Response is generic ACK / NACK message.
+ */
+struct ti_sci_msg_req_set_io_isolation {
+	struct ti_sci_msg_hdr hdr;
+	u8 state;
+} __packed;
+
+/**
+ * struct ti_sci_msg_req_lpm_set_device_constraint - Request for
+ * TISCI_MSG_LPM_SET_DEVICE_CONSTRAINT.
+ *
+ * @hdr:	TISCI header to provide ACK/NAK flags to the host.
+ * @id:	Device ID of device whose constraint has to be modified.
+ * @state:	The desired state of device constraint: set or clear.
+ * @rsvd:	Reserved for future use.
+ *
+ * This message is used by host to set constraint on the device. This can be
+ * sent anytime after boot before prepare sleep message. 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. Note: Access Restriction: Exclusivity flag of Device will
+ * be honored. If some other host already has constraint on this device ID,
+ * NACK will be returned.
+ */
+struct ti_sci_msg_req_lpm_set_device_constraint {
+	struct ti_sci_msg_hdr hdr;
+	u32 id;
+	u8 state;
+	u32 rsvd[2];
+} __packed;
+
+/**
+ * struct ti_sci_msg_req_lpm_set_latency_constraint - Request for
+ * TISCI_MSG_LPM_SET_LATENCY_CONSTRAINT.
+ *
+ * @hdr:	TISCI header to provide ACK/NAK flags to the host.
+ * @wkup_latency:	The maximum acceptable latency to wake up from low power mode
+ *			in milliseconds. The deeper the state, the higher the latency.
+ * @state:	The desired state of wakeup latency constraint: set or clear.
+ * @rsvd:	Reserved for future use.
+ *
+ * This message is used by host to set wakeup latency from low power mode. This can
+ * be sent anytime after boot before prepare sleep message, and can be sent 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 wakeup latency constraint, the host ensures that the resume time
+ * from selected low power mode will be less than the constraint value.
+ */
+struct ti_sci_msg_req_lpm_set_latency_constraint {
+	struct ti_sci_msg_hdr hdr;
+	u16 latency;
+	u8 state;
+	u32 rsvd;
+} __packed;
+
 #define TI_SCI_IRQ_SECONDARY_HOST_INVALID	0xff
 
 /**
diff --git a/include/linux/soc/ti/ti_sci_protocol.h b/include/linux/soc/ti/ti_sci_protocol.h
index bd0d11af76c5..9f92a8071972 100644
--- a/include/linux/soc/ti/ti_sci_protocol.h
+++ b/include/linux/soc/ti/ti_sci_protocol.h
@@ -195,6 +195,51 @@ struct ti_sci_clk_ops {
 			u64 *current_freq);
 };
 
+/* TISCI LPM wake up sources */
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_WKUP_I2C0	0x00
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_WKUP_UART0	0x10
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_MCU_GPIO0	0x20
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_WKUP_ICEMELTER0	0x30
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_WKUP_TIMER0	0x40
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_WKUP_TIMER1	0x41
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_WKUP_RTC0	0x50
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_RESET		0x60
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_USB0		0x70
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_USB1		0x71
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_MAIN_IO		0x80
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_MCU_IO		0x81
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_CAN_IO		0x82
+#define TISCI_MSG_VALUE_LPM_WAKE_SOURCE_INVALID		0xFF
+
+/* TISCI LPM IO isolation control values */
+#define TISCI_MSG_VALUE_IO_ENABLE			1
+#define TISCI_MSG_VALUE_IO_DISABLE			0
+
+/* TISCI LPM constraint state values */
+#define TISCI_MSG_CONSTRAINT_SET			1
+#define TISCI_MSG_CONSTRAINT_CLR			0
+
+/**
+ * struct ti_sci_pm_ops - Low Power Mode (LPM) control operations
+ * @lpm_wake_reason: Get the wake up source that woke the SoC from LPM
+ *		- source: The wake up source that woke soc from LPM.
+ *		- timestamp: Timestamp at which soc woke.
+ * @set_device_constraint: Set LPM constraint on behalf of a device
+ *		- id: Device Identifier
+ *		- state: The desired state of device constraint: set or clear.
+ * @set_latency_constraint: Set LPM resume latency constraint
+ *		- latency: maximum acceptable latency to wake up from low power mode
+ *		- state: The desired state of latency constraint: set or clear.
+ */
+struct ti_sci_pm_ops {
+	int (*lpm_wake_reason)(const struct ti_sci_handle *handle,
+			       u32 *source, u64 *timestamp);
+	int (*set_device_constraint)(const struct ti_sci_handle *handle,
+				     u32 id, u8 state);
+	int (*set_latency_constraint)(const struct ti_sci_handle *handle,
+				      u16 latency, u8 state);
+};
+
 /**
  * struct ti_sci_resource_desc - Description of TI SCI resource instance range.
  * @start:	Start index of the first resource range.
@@ -539,6 +584,7 @@ struct ti_sci_ops {
 	struct ti_sci_core_ops core_ops;
 	struct ti_sci_dev_ops dev_ops;
 	struct ti_sci_clk_ops clk_ops;
+	struct ti_sci_pm_ops pm_ops;
 	struct ti_sci_rm_core_ops rm_core_ops;
 	struct ti_sci_rm_irq_ops rm_irq_ops;
 	struct ti_sci_rm_ringacc_ops rm_ring_ops;
-- 
2.45.2

[PATCH v8 2/3] firmware: ti_sci: Add support for querying the firmware caps

[Markus Schneider-Pargmann]

From: Georgi Vlaev <g-vlaev@ti.com>

Add support for the TISCI_MSG_QUERY_FW_CAPS message, used to retrieve
the firmware capabilities of the currently running system firmware. The
message belongs to the TISCI general core message API [1] and is
available in SysFW version 08.04.03 and above. Currently, the message is
supported on devices with split architecture of the system firmware (DM
+ TIFS) like AM62x. Old revisions or not yet supported platforms will
NACK this request.

We're using this message locally in ti_sci.c to get the low power
featutes of the FW/SoC. As there's no other kernel consumers yet, this
is not added to struct ti_sci_core_ops.

Sysfw version >= 10.00.04 support LPM_DM_MANAGED capability [2], where
Device Mgr firmware now manages which low power mode is chosen. Going
forward, this is the default configuration supported for TI AM62 family
of devices. The state chosen by the DM can be influenced by sending
constraints using the new LPM constraint APIs.

[1] https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/general/core.html
[2] https://downloads.ti.com/tisci/esd/latest/2_tisci_msgs/general/core.html#tisci-msg-query-fw-caps

Signed-off-by: Georgi Vlaev <g-vlaev@ti.com>
[vibhore@ti.com: Support for LPM_DM_MANAGED mode]
Signed-off-by: Vibhore Vardhan <vibhore@ti.com>
Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
---
 drivers/firmware/ti_sci.c | 73 +++++++++++++++++++++++++++++++++++++++
 drivers/firmware/ti_sci.h | 22 ++++++++++++
 2 files changed, 95 insertions(+)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 3599aeecef86..d7a3990a6353 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/soc/ti/ti-msgmgr.h>
 #include <linux/soc/ti/ti_sci_protocol.h>
+#include <linux/sys_soc.h>
 #include <linux/reboot.h>
 
 #include "ti_sci.h"
@@ -98,6 +99,7 @@ struct ti_sci_desc {
  * @minfo:	Message info
  * @node:	list head
  * @host_id:	Host ID
+ * @fw_caps:	FW/SoC low power capabilities
  * @users:	Number of users of this instance
  */
 struct ti_sci_info {
@@ -114,6 +116,7 @@ struct ti_sci_info {
 	struct ti_sci_xfers_info minfo;
 	struct list_head node;
 	u8 host_id;
+	u64 fw_caps;
 	/* protected by ti_sci_list_mutex */
 	int users;
 };
@@ -1929,6 +1932,62 @@ static int ti_sci_cmd_set_latency_constraint(const struct ti_sci_handle *handle,
 	return ret;
 }
 
+/**
+ * ti_sci_msg_cmd_query_fw_caps() - Get the FW/SoC capabilities
+ * @handle:		Pointer to TI SCI handle
+ * @fw_caps:		Each bit in fw_caps indicating one FW/SOC capability
+ *
+ * Return: 0 if all went well, else returns appropriate error value.
+ */
+static int ti_sci_msg_cmd_query_fw_caps(const struct ti_sci_handle *handle,
+					u64 *fw_caps)
+{
+	struct ti_sci_info *info;
+	struct ti_sci_xfer *xfer;
+	struct ti_sci_msg_resp_query_fw_caps *resp;
+	struct device *dev;
+	int ret = 0;
+
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	if (!handle)
+		return -EINVAL;
+
+	info = handle_to_ti_sci_info(handle);
+	dev = info->dev;
+
+	xfer = ti_sci_get_one_xfer(info, TI_SCI_MSG_QUERY_FW_CAPS,
+				   TI_SCI_FLAG_REQ_ACK_ON_PROCESSED,
+				   sizeof(struct ti_sci_msg_hdr),
+				   sizeof(*resp));
+	if (IS_ERR(xfer)) {
+		ret = PTR_ERR(xfer);
+		dev_err(dev, "Message alloc failed(%d)\n", ret);
+		return ret;
+	}
+
+	ret = ti_sci_do_xfer(info, xfer);
+	if (ret) {
+		dev_err(dev, "Mbox send fail %d\n", ret);
+		goto fail;
+	}
+
+	resp = (struct ti_sci_msg_resp_query_fw_caps *)xfer->xfer_buf;
+
+	if (!ti_sci_is_response_ack(resp)) {
+		ret = -ENODEV;
+		goto fail;
+	}
+
+	if (fw_caps)
+		*fw_caps = resp->fw_caps;
+
+fail:
+	ti_sci_put_one_xfer(&info->minfo, xfer);
+
+	return ret;
+}
+
 static int ti_sci_cmd_core_reboot(const struct ti_sci_handle *handle)
 {
 	struct ti_sci_info *info;
@@ -3113,6 +3172,12 @@ static void ti_sci_setup_ops(struct ti_sci_info *info)
 
 	pmops->lpm_wake_reason = ti_sci_msg_cmd_lpm_wake_reason;
 
+	if (info->fw_caps & MSG_FLAG_CAPS_LPM_DM_MANAGED) {
+		pr_debug("detected DM managed LPM in fw_caps\n");
+		ops->pm_ops.set_device_constraint = ti_sci_cmd_set_device_constraint;
+		ops->pm_ops.set_latency_constraint = ti_sci_cmd_set_latency_constraint;
+	}
+
 	rm_core_ops->get_range = ti_sci_cmd_get_resource_range;
 	rm_core_ops->get_range_from_shost =
 				ti_sci_cmd_get_resource_range_from_shost;
@@ -3671,6 +3736,14 @@ static int ti_sci_probe(struct platform_device *pdev)
 		goto out;
 	}
 
+	/*
+	 * Check if the firmware supports any optional low power modes.
+	 * Old revisions of TIFS (< 08.04) will NACK the request.
+	 */
+	ret = ti_sci_msg_cmd_query_fw_caps(&info->handle, &info->fw_caps);
+	if (ret || !(info->fw_caps & MSG_FLAG_CAPS_GENERIC))
+		pr_debug("Unable to detect LPM capabilities in fw_caps\n");
+
 	ti_sci_setup_ops(info);
 
 	ret = devm_register_restart_handler(dev, tisci_reboot_handler, info);
diff --git a/drivers/firmware/ti_sci.h b/drivers/firmware/ti_sci.h
index 424bc192ce3e..b8bba5d521d7 100644
--- a/drivers/firmware/ti_sci.h
+++ b/drivers/firmware/ti_sci.h
@@ -19,6 +19,7 @@
 #define TI_SCI_MSG_WAKE_REASON	0x0003
 #define TI_SCI_MSG_GOODBYE	0x0004
 #define TI_SCI_MSG_SYS_RESET	0x0005
+#define TI_SCI_MSG_QUERY_FW_CAPS	0x0022
 
 /* Device requests */
 #define TI_SCI_MSG_SET_DEVICE_STATE	0x0200
@@ -139,6 +140,27 @@ struct ti_sci_msg_req_reboot {
 	struct ti_sci_msg_hdr hdr;
 } __packed;
 
+/**
+ * struct ti_sci_msg_resp_query_fw_caps - Response for query firmware caps
+ * @hdr:	Generic header
+ * @fw_caps:	Each bit in fw_caps indicating one FW/SOC capability
+ *		MSG_FLAG_CAPS_GENERIC: Generic capability (LPM not supported)
+ *		MSG_FLAG_CAPS_LPM_PARTIAL_IO: Partial IO in LPM
+ *		MSG_FLAG_CAPS_LPM_DM_MANAGED: LPM can be managed by DM
+ *
+ * Response to a generic message with message type TI_SCI_MSG_QUERY_FW_CAPS
+ * providing currently available SOC/firmware capabilities. SoC that don't
+ * support low power modes return only MSG_FLAG_CAPS_GENERIC capability.
+ */
+struct ti_sci_msg_resp_query_fw_caps {
+	struct ti_sci_msg_hdr hdr;
+#define MSG_FLAG_CAPS_GENERIC		TI_SCI_MSG_FLAG(0)
+#define MSG_FLAG_CAPS_LPM_PARTIAL_IO	TI_SCI_MSG_FLAG(4)
+#define MSG_FLAG_CAPS_LPM_DM_MANAGED	TI_SCI_MSG_FLAG(5)
+#define MSG_MASK_CAPS_LPM		GENMASK_ULL(4, 1)
+	u64 fw_caps;
+} __packed;
+
 /**
  * struct ti_sci_msg_req_set_device_state - Set the desired state of the device
  * @hdr:		Generic header
-- 
2.45.2

[PATCH v8 3/3] firmware: ti_sci: Add system suspend and resume call

[Markus Schneider-Pargmann]

From: Vibhore Vardhan <vibhore@ti.com>

Introduce system suspend call that enables the ti_sci driver to support
low power mode when the user space issues a suspend to mem.

Also, write a ti_sci_prepare_system_suspend call to be used in the driver
suspend handler to allow the system to identify the low power mode being
entered and if necessary, send TISCI_MSG_PREPARE_SLEEP with information
about the mode being entered.

Sysfw version >= 10.00.04 support LPM_DM_MANAGED capability [2], where
Device Mgr firmware now manages which low power mode is chosen. Going
forward, this is the default configuration supported for TI AM62 family
of devices. The state chosen by the DM can be influenced by sending
constraints using the new LPM constraint APIs.

In case the firmware does not support LPM_DM_MANAGED mode, the mode
selection logic can be extended as needed. If no suspend-to-RAM modes
are supported, return without taking any action.

We're using "pm_suspend_target_state" to map the kernel's target suspend
state to SysFW low power mode. Make sure this is available only when
CONFIG_SUSPEND is enabled.

Suspend has to be split into two parts, ti_sci_suspend() will send
the prepare sleep message to prepare suspend. ti_sci_suspend_noirq()
sets IO isolation which needs to be done as late as possible to avoid
any issues. On resume this has to be done as early as possible.

Co-developed-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Georgi Vlaev <g-vlaev@ti.com>
Signed-off-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Vibhore Vardhan <vibhore@ti.com>
Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
---
 drivers/firmware/ti_sci.c | 82 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index d7a3990a6353..c6544cc12417 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/soc/ti/ti-msgmgr.h>
 #include <linux/soc/ti/ti_sci_protocol.h>
+#include <linux/suspend.h>
 #include <linux/sys_soc.h>
 #include <linux/reboot.h>
 
@@ -3608,6 +3609,84 @@ static int tisci_reboot_handler(struct sys_off_data *data)
 	return NOTIFY_BAD;
 }
 
+#ifdef CONFIG_SUSPEND
+static int ti_sci_prepare_system_suspend(struct ti_sci_info *info)
+{
+	u8 mode;
+
+	/*
+	 * Map and validate the target Linux suspend state to TISCI LPM.
+	 * Default is to let Device Manager select the low power mode.
+	 */
+	switch (pm_suspend_target_state) {
+	case PM_SUSPEND_MEM:
+		if (info->fw_caps & MSG_FLAG_CAPS_LPM_DM_MANAGED)
+			mode = TISCI_MSG_VALUE_SLEEP_MODE_DM_MANAGED;
+		else
+			/* DM Managed is not supported by the firmware. */
+			return -EOPNOTSUPP;
+		break;
+	default:
+		/*
+		 * Do not fail if we don't have action to take for a
+		 * specific suspend mode.
+		 */
+		return 0;
+	}
+
+	return ti_sci_cmd_prepare_sleep(&info->handle, mode, 0, 0, 0);
+}
+
+static int ti_sci_suspend(struct device *dev)
+{
+	struct ti_sci_info *info = dev_get_drvdata(dev);
+	int ret;
+
+	ret = ti_sci_prepare_system_suspend(info);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int ti_sci_suspend_noirq(struct device *dev)
+{
+	struct ti_sci_info *info = dev_get_drvdata(dev);
+	int ret = 0;
+
+	ret = ti_sci_cmd_set_io_isolation(&info->handle, TISCI_MSG_VALUE_IO_ENABLE);
+	if (ret)
+		return ret;
+	dev_dbg(dev, "%s: set isolation: %d\n", __func__, ret);
+
+	return 0;
+}
+
+static int ti_sci_resume_noirq(struct device *dev)
+{
+	struct ti_sci_info *info = dev_get_drvdata(dev);
+	u32 source;
+	u64 time;
+	int ret = 0;
+
+	ret = ti_sci_cmd_set_io_isolation(&info->handle, TISCI_MSG_VALUE_IO_DISABLE);
+	if (ret)
+		return ret;
+	dev_dbg(dev, "%s: disable isolation: %d\n", __func__, ret);
+
+	ti_sci_msg_cmd_lpm_wake_reason(&info->handle, &source, &time);
+	dev_info(dev, "%s: wakeup source: 0x%X\n", __func__, source);
+
+	return 0;
+}
+
+static const struct dev_pm_ops ti_sci_pm_ops = {
+	.suspend = ti_sci_suspend,
+	.suspend_noirq = ti_sci_suspend_noirq,
+	.resume_noirq = ti_sci_resume_noirq,
+};
+#endif  /* CONFIG_SUSPEND */
+
 /* Description for K2G */
 static const struct ti_sci_desc ti_sci_pmmc_k2g_desc = {
 	.default_host_id = 2,
@@ -3777,6 +3856,9 @@ static struct platform_driver ti_sci_driver = {
 		   .name = "ti-sci",
 		   .of_match_table = of_match_ptr(ti_sci_of_match),
 		   .suppress_bind_attrs = true,
+#ifdef CONFIG_SUSPEND
+		   .pm = &ti_sci_pm_ops,
+#endif
 	},
 };
 module_platform_driver(ti_sci_driver);
-- 
2.45.2

Re: [PATCH v8 1/3] firmware: ti_sci: Introduce Power Management Ops

[Nishanth Menon]

On 21:54-20240801, Markus Schneider-Pargmann wrote:
> From: Dave Gerlach <d-gerlach@ti.com>
[...]

> +	pmops->lpm_wake_reason = ti_sci_msg_cmd_lpm_wake_reason;

did you miss populating the rest of the pm ops?
	See https://lore.kernel.org/all/202408031302.28NpPykP-lkp@intel.com/

It might be better to introduce the APIs one at a time?

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D

Re: [PATCH v8 2/3] firmware: ti_sci: Add support for querying the firmware caps

[Nishanth Menon]

On 21:54-20240801, Markus Schneider-Pargmann wrote:
[...]

>  static int ti_sci_cmd_core_reboot(const struct ti_sci_handle *handle)
>  {
>  	struct ti_sci_info *info;
> @@ -3113,6 +3172,12 @@ static void ti_sci_setup_ops(struct ti_sci_info *info)
>  
>  	pmops->lpm_wake_reason = ti_sci_msg_cmd_lpm_wake_reason;
>  
> +	if (info->fw_caps & MSG_FLAG_CAPS_LPM_DM_MANAGED) {
> +		pr_debug("detected DM managed LPM in fw_caps\n");
> +		ops->pm_ops.set_device_constraint = ti_sci_cmd_set_device_constraint;
> +		ops->pm_ops.set_latency_constraint = ti_sci_cmd_set_latency_constraint;
pmops-> ?

Also lpm_wake_reason makes sense only if the flag is set, so
this should probably be the first patch in your series?

> +	}

Side-note: please drop bouncing emails from your patch CC list.

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D

Re: [PATCH v8 1/3] firmware: ti_sci: Introduce Power Management Ops

[Markus Schneider-Pargmann]

Hi Nishanth,

On Tue, Aug 06, 2024 at 10:39:12AM GMT, Nishanth Menon wrote:
> On 21:54-20240801, Markus Schneider-Pargmann wrote:
> > From: Dave Gerlach <d-gerlach@ti.com>
> [...]
> 
> > +	pmops->lpm_wake_reason = ti_sci_msg_cmd_lpm_wake_reason;
> 
> did you miss populating the rest of the pm ops?
> 	See https://lore.kernel.org/all/202408031302.28NpPykP-lkp@intel.com/

No, I didn't miss populating the pmops.

set_latency_constraint() and set_device_constraint() are only added to
pmops once the firmware capabilities are added in the next patch.
set_io_isolation() and prepare_sleep() are not added to pmops as the
usage outside of ti_sci.c is not planned. These are only used for
suspend/resume in the third patch.

I will rearrange the patches and integrate the functions required for
suspend/resume with the suspend/resume patch to avoid any build
warnings.

Best
Markus

> It might be better to introduce the APIs one at a time?
> 
> -- 
> Regards,
> Nishanth Menon
> Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D