linux-toradex.git/drivers/resctrl/mpam_internal.h, branch v6.19-rc2

arm_mpam: Add kunit tests for props_mismatch()

2025-11-19T18:34:24+00:00

When features are mismatched between MSC the way features are combined
to the class determines whether resctrl can support this SoC.

Add some tests to illustrate the sort of thing that is expected to
work, and those that must be removed.

Signed-off-by: James Morse 
Reviewed-by: Ben Horgan 
Reviewed-by: Fenghua Yu 
Reviewed-by: Gavin Shan 
Reviewed-by: Shaopeng Tan 
Tested-by: Fenghua Yu 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Shaopeng Tan 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Add helper to reset saved mbwu state

2025-11-19T18:34:24+00:00

resctrl expects to reset the bandwidth counters when the filesystem
is mounted.

To allow this, add a helper that clears the saved mbwu state. Instead
of cross calling to each CPU that can access the component MSC to
write to the counter, set a flag that causes it to be zero'd on the
the next read. This is easily done by forcing a configuration update.

Signed-off-by: James Morse 
Cc: Peter Newman 
Reviewed-by: Fenghua Yu 
Reviewed-by: Gavin Shan 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Shaopeng Tan 
Tested-by: Fenghua Yu 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Shaopeng Tan 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Probe for long/lwd mbwu counters

2025-11-19T18:34:23+00:00

mpam v0.1 and versions above v1.0 support optional long counter for
memory bandwidth monitoring. The MPAMF_MBWUMON_IDR register has fields
indicating support for long counters.

Probe these feature bits.

The mpam_feat_msmon_mbwu feature is used to indicate that bandwidth
monitors are supported, instead of muddling this with which size of
bandwidth monitors, add an explicit 31 bit counter feature.

Signed-off-by: Rohit Mathew 
[ morse: Added 31bit counter feature to simplify later logic ]
Signed-off-by: James Morse 
Reviewed-by: Ben Horgan 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Gavin Shan 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Fenghua Yu 
Tested-by: Fenghua Yu 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Consider overflow in bandwidth counter state

2025-11-19T18:34:23+00:00

Use the overflow status bit to track overflow on each bandwidth counter
read and add the counter size to the correction when overflow is detected.

This assumes that only a single overflow has occurred since the last read
of the counter. Overflow interrupts, on hardware that supports them could
be used to remove this limitation.

Cc: Zeng Heng 
Reviewed-by: Gavin Shan 
Reviewed-by: Zeng Heng 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Fenghua Yu 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Shaopeng Tan 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Track bandwidth counter state for power management

2025-11-19T18:34:23+00:00

Bandwidth counters need to run continuously to correctly reflect the
bandwidth.

Save the counter state when the hardware is reset due to CPU hotplug.
Add struct mbwu_state to track the bandwidth counter. Support for
tracking overflow with the same structure will be added in a
subsequent commit.

Cc: Zeng Heng 
Reviewed-by: Gavin Shan 
Reviewed-by: Zeng Heng 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Fenghua Yu 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Shaopeng Tan 
Tested-by: Hanjun Guo 
Signed-off-by: James Morse 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Add mpam_msmon_read() to read monitor value

2025-11-19T18:34:23+00:00

Reading a monitor involves configuring what you want to monitor, and
reading the value. Components made up of multiple MSC may need values
from each MSC. MSCs may take time to configure, returning 'not ready'.
The maximum 'not ready' time should have been provided by firmware.

Add mpam_msmon_read() to hide all this. If (one of) the MSC returns
not ready, then wait the full timeout value before trying again.

CC: Shanker Donthineni 
Cc: Shaopeng Tan (Fujitsu) 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Gavin Shan 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Fenghua Yu 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Hanjun Guo 
Signed-off-by: James Morse 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Add helpers to allocate monitors

2025-11-19T18:34:22+00:00

MPAM's MSC support a number of monitors, each of which supports
bandwidth counters, or cache-storage-utilisation counters. To use
a counter, a monitor needs to be configured. Add helpers to allocate
and free CSU or MBWU monitors.

Signed-off-by: James Morse 
Reviewed-by: Ben Horgan 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Gavin Shan 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Fenghua Yu 
Tested-by: Fenghua Yu 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Probe and reset the rest of the features

2025-11-19T18:34:22+00:00

MPAM supports more features than are going to be exposed to resctrl.
For partid other than 0, the reset values of these controls isn't
known.

Discover the rest of the features so they can be reset to avoid any
side effects when resctrl is in use.

PARTID narrowing allows MSC/RIS to support less configuration space than
is usable. If this feature is found on a class of device we are likely
to use, then reduce the partid_max to make it usable. This allows us
to map a PARTID to itself.

CC: Rohit Mathew 
CC: Zeng Heng 
CC: Dave Martin 
Signed-off-by: James Morse 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Gavin Shan 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Fenghua Yu 
Tested-by: Fenghua Yu 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Allow configuration to be applied and restored during cpu online

2025-11-19T18:34:22+00:00

When CPUs come online the MSC's original configuration should be restored.

Add struct mpam_config to hold the configuration. For each component, this
has a bitmap of features that have been changed from the reset values. The
mpam_config is also used on RIS reset where all bits are set to ensure all
features are reset.

Once the maximum partid is known, allocate a configuration array for each
component, and reprogram each RIS configuration from this.

CC: Dave Martin 
Signed-off-by: James Morse 
Cc: Fujitsu Fujitsu 
Cc: Peter Newman peternewman@google.com
Reviewed-by: Gavin Shan 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Fenghua Yu 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Shaopeng Tan 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Use a static key to indicate when mpam is enabled

2025-11-19T18:34:22+00:00

Once all the MSC have been probed, the system wide usable number of
PARTID is known and the configuration arrays can be allocated.

After this point, checking all the MSC have been probed is pointless,
and the cpuhp callbacks should restore the configuration, instead of
just resetting the MSC.

Add a static key to enable this behaviour. This will also allow MPAM
to be disabled in response to an error, and the architecture code to
enable/disable the context switch of the MPAM system registers.

Signed-off-by: James Morse 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Ben Horgan 
Reviewed-by: Fenghua Yu 
Reviewed-by: Gavin Shan 
Reviewed-by: Shaopeng Tan 
Tested-by: Fenghua Yu 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas