linux-toradex.git/drivers/pmdomain/ti, branch master

pmdomain: ti-sci: Set PD on/off state according to the HW state

2025-09-12T12:27:15+00:00

At the moment the driver sets the power state of all the PDs it creates
to off, regardless of the actual HW state. This has two drawbacks:

1) The kernel cannot disable unused PDs automatically for power saving,
   as it thinks they are off already

2) A more specific case (but perhaps applicable to other scenarios
   also): bootloader enabled splash-screen cannot be kept on the screen.

The issue in 2) is that the driver framework automatically enables the
device's PD before calling probe() and disables it after the probe().
This means that when the display subsystem (DSS) driver probes, but e.g.
fails due to deferred probing, the DSS PD gets turned off and the driver
cannot do anything to affect that.

Solving the 2) requires more changes to actually keep the PD on during
the boot, but a prerequisite for it is to have the correct power state
for the PD.

The downside with this patch is that it takes time to call the 'is_on'
op, and we need to call it for each PD. In my tests with AM62 SK, using
defconfig, I see an increase from ~3.5ms to ~7ms. However, the added
feature is valuable, so in my opinion it's worth it.

The performance could probably be improved with a new firmware API which
returns the power states of all the PDs.

There's also a related HW issue at play here: if the DSS IP is enabled
and active, and its PD is turned off without first disabling the DSS
display outputs, the DSS IP will hang and causes the kernel to halt if
and when the DSS driver accesses the DSS registers the next time.

With the current upstream kernel, with this patch applied, this means
that if the bootloader enables the display, and the DSS driver is
compiled as a module, the kernel will at some point disable unused PDs,
including the DSS PD. When the DSS module is later loaded, it will hang
the kernel.

The same issue is already there, even without this patch, as the DSS
driver may hit deferred probing, which causes the PD to be turned off,
and leading to kernel halt when the DSS driver is probed again. This
issue has been made quite rare with some arrangements in the DSS
driver's probe, but it's still there.

With recent change from Ulf (e.g. commit 13a4b7fb6260 ("pmdomain: core:
Leave powered-on genpds on until late_initcall_sync")), the sync state
mechanism comes to rescue. It will keep the power domains enabled, until
the drivers have probed, or the sync-state is triggered via some other
mechanism (e.g. manually by the boot scripts).

Reviewed-by: Kevin Hilman 
Tested-by: Kevin Hilman 
Signed-off-by: Tomi Valkeinen 
Signed-off-by: Ulf Hansson

pmdomain: ti: Select PM_GENERIC_DOMAINS

2025-07-15T14:08:19+00:00

Select PM_GENERIC_DOMAINS instead of depending on it to ensure
it is always enabled when TI_SCI_PM_DOMAINS is selected.
Since PM_GENERIC_DOMAINS is an implicit symbol, it can only be enabled
through 'select' and cannot be explicitly enabled in configuration.
This simplifies the dependency chain and prevents build issues

Signed-off-by: Guillaume La Roque 
Reviewed-by: Nishanth Menon 
Link: https://lore.kernel.org/r/20250715-depspmdomain-v2-1-6f0eda3ce824@baylibre.com
Signed-off-by: Ulf Hansson

pmdomain: ti: Fix STANDBY handling of PER power domain

2025-05-19T14:11:05+00:00

Per AM335x TRM[1](section 8.1.4.3 Power mode), in case of STANDBY,
PER domain should be ON. So, fix the PER power domain handling on standby.

[1] https://www.ti.com/lit/ug/spruh73q/spruh73q.pdf

Signed-off-by: Sukrut Bellary 
Reviewed-by: Kevin Hilman 
Tested-by: Judith Mendez 
Link: https://lore.kernel.org/r/20250318230042.3138542-3-sbellary@baylibre.com
Signed-off-by: Ulf Hansson

pmdomain: ti: Use of_property_present() for non-boolean properties

2025-02-13T13:43:02+00:00

On BeagleBone Black:

    OF: /ocp: Read of boolean property 'clocks' with a value.
    OF: /ocp/interconnect@44c00000: Read of boolean property 'clocks' with a value.
    OF: /ocp/interconnect@48000000: Read of boolean property 'clocks' with a value.
    OF: /ocp/interconnect@4a000000: Read of boolean property 'clocks' with a value.

The use of of_property_read_bool() for non-boolean properties is
deprecated in favor of of_property_present() when testing for property
presence.

Signed-off-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/r/accb12bd6d048d95bd1feea07dd1a799ad3f8b31.1737532423.git.geert+renesas@glider.be
Signed-off-by: Ulf Hansson

pmdomain: ti_sci: handle wake IRQs for IO daisy chain wakeups

2024-12-10T11:37:26+00:00

When a device supports IO daisy-chain wakeups, it uses a dedicated
wake IRQ.  Devices with IO daisy-chain wakeups enabled should not set
wakeup constraints since these can happen even from deep power states,
so should not prevent the DM from picking deep power states.

Wake IRQs are set with dev_pm_set_wake_irq() or
dev_pm_set_dedicated_wake_irq().  The latter is used by the serial
driver used on K3 platforms (drivers/tty/serial/8250/8250_omap.c)
when the interrupts-extended property is used to describe the
dedicated wakeup interrupt.

Detect these wake IRQs in the suspend path, and if set, skip sending
constraint.

Tested-by: Dhruva Gole 
Signed-off-by: Kevin Hilman 
Reviewed-by: Dhruva Gole 
Message-ID: <20241206-lpm-v6-10-constraints-pmdomain-v6-3-833980158c68@baylibre.com>
Signed-off-by: Ulf Hansson

pmdomain: ti_sci: add wakeup constraint management

2024-12-10T11:37:26+00:00

During system-wide suspend, check all devices connected to PM domain
to see if they are wakeup-enabled.  If so, set a TI SCI device
constraint.

Note: DM firmware clears all constraints on resume.

Co-developed-by: Vibhore Vardhan 
Signed-off-by: Vibhore Vardhan 
Reviewed-by: Ulf Hansson 
Tested-by: Dhruva Gole 
Signed-off-by: Kevin Hilman 
Reviewed-by: Dhruva Gole 
Message-ID: <20241206-lpm-v6-10-constraints-pmdomain-v6-2-833980158c68@baylibre.com>
Signed-off-by: Ulf Hansson

pmdomain: ti_sci: add per-device latency constraint management

2024-12-10T11:37:26+00:00

For each device in a TI SCI PM domain, check whether the device has
any resume latency constraints set via per-device PM QoS.  If
constraints are set, send them to DM via the new SCI constraints API.

Checking for constraints happen for each device before system-wide
suspend (via ->suspend() hook.)

An important detail here is that the PM domain driver inserts itself
into the path of both the ->suspend() and ->resume() hook path
of *all* devices in the PM domain.  This allows generic PM domain code
to handle the constraint management and communication with TI SCI.

Further, this allows device drivers to use existing PM QoS APIs to
add/update constraints.

DM firmware clears constraints during its resume, so Linux has
to check/update/send constraints each time system suspends.

Also note that the PM QoS framework uses usecs as the units for
latency whereas the TI SCI firmware uses msecs, so a conversion is
needed before passing to TI SCI.

Co-developed-by: Vibhore Vardhan 
Signed-off-by: Vibhore Vardhan 
Reviewed-by: Markus Schneider-Pargmann 
Reviewed-by: Ulf Hansson 
Tested-by: Dhruva Gole 
Signed-off-by: Kevin Hilman 
Reviewed-by: Dhruva Gole 
Message-ID: <20241206-lpm-v6-10-constraints-pmdomain-v6-1-833980158c68@baylibre.com>
Signed-off-by: Ulf Hansson

pmdomain: ti-sci: Use scope based of_node_put() to simplify code.

2024-10-31T10:30:57+00:00

Use scope based of_node_put() to simplify the code logic, and we don't
need to call of_node_put(). Besides, put of_parse_phandle_with_args() in
the while loop to make code more simple.

Signed-off-by: Zhang Zekun 
Reviewed-by: Dhruva Gole 
Message-ID: <20241024030442.119506-3-zhangzekun11@huawei.com>
Signed-off-by: Ulf Hansson

pmdomain: ti-sci: Add missing of_node_put() for args.np

2024-10-31T10:30:57+00:00

of_parse_phandle_with_args() needs to call of_node_put() to decrement
the refcount of args.np. So, Add the missing of_node_put() in the loop.

Fixes: efa5c01cd7ee ("soc: ti: ti_sci_pm_domains: switch to use multiple genpds instead of one")
Signed-off-by: Zhang Zekun 
Reviewed-by: Dhruva Gole 
Message-ID: <20241024030442.119506-2-zhangzekun11@huawei.com>
Signed-off-by: Ulf Hansson

pmdomain: ti-sci: set the GENPD_FLAG_ACTIVE_WAKEUP flag for all PM domains

2024-10-30T16:14:00+00:00

With this flag, if a device is marked on the wakeup path, the corresponding
PM domain is kept powered on.

This commit fixes the no_console_suspend support for some TI platforms
(tested on J7200). In case of no_console_suspend the serial core marks the
device on the wakeup path, but without this patch the power domain is
powered off anyway.

Suggested-by: Théo Lebrun 
Signed-off-by: Thomas Richard 
Reviewed-by: Kevin Hilman 
Link: https://lore.kernel.org/r/20241022-8250-omap-no-console-suspend-v2-1-cc3d102b8a1e@bootlin.com
Signed-off-by: Ulf Hansson