linux/drivers/platform
Shyam Sundar S K 7c45534afa platform/x86/amd/pmf: Add support for PMF Policy Binary
PMF Policy binary is a encrypted and signed binary that will be part
of the BIOS. PMF driver via the ACPI interface checks the existence
of Smart PC bit. If the advertised bit is found, PMF driver walks
the acpi namespace to find out the policy binary size and the address
which has to be passed to the TA during the TA init sequence.

The policy binary is comprised of inputs (or the events) and outputs
(or the actions). With the PMF ecosystem, OEMs generate the policy
binary (or could be multiple binaries) that contains a supported set
of inputs and outputs which could be specifically carved out for each
usage segment (or for each user also) that could influence the system
behavior either by enriching the user experience or/and boost/throttle
power limits.

Once the TA init command succeeds, the PMF driver sends the changing
events in the current environment to the TA for a constant sampling
frequency time (the event here could be a lid close or open) and
if the policy binary has corresponding action built within it, the
TA sends the action for it in the subsequent enact command.

If the inputs sent to the TA has no output defined in the policy
binary generated by OEMs, there will be no action to be performed
by the PMF driver.

Example policies:

1) if slider is performance ; set the SPL to 40W
Here PMF driver registers with the platform profile interface and
when the slider position is changed, PMF driver lets the TA know
about this. TA sends back an action to update the Sustained
Power Limit (SPL). PMF driver updates this limit via the PMFW mailbox.

2) if user_away ; then lock the system
Here PMF driver hooks to the AMD SFH driver to know the user presence
and send the inputs to TA and if the condition is met, the TA sends
the action of locking the system. PMF driver generates a uevent and
based on the udev rule in the userland the system gets locked with
systemctl.

The intent here is to provide the OEM's to make a policy to lock the
system when the user is away ; but the userland can make a choice to
ignore it.

The OEMs will have an utility to create numerous such policies and
the policies shall be reviewed by AMD before signing and encrypting
them. Policies are shared between operating systems to have seemless user
experience.

Since all this action has to happen via the "amdtee" driver, currently
there is no caller for it in the kernel which can load the amdtee driver.
Without amdtee driver loading onto the system the "tee" calls shall fail
from the PMF driver. Hence an explicit MODULE_SOFTDEP has been added
to address this.

Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20231212014705.2017474-5-Shyam-sundar.S-k@amd.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2023-12-18 12:47:46 +01:00
..
chrome USB/Thunderbolt changes for 6.7-rc1 2023-11-03 16:00:42 -10:00
goldfish platform: goldfish: pipe: Use platform_get_irq() to get the interrupt 2022-03-18 13:55:21 +01:00
loongarch platform/loongarch: laptop: Fix possible UAF and simplify generic_acpi_laptop_init() 2022-10-29 16:29:31 +08:00
mellanox platform-drivers-x86 for v6.7-3 2023-12-11 11:22:02 +01:00
mips platform/mips: Adjust Kconfig to keep consistency 2022-12-08 11:51:52 +01:00
olpc platform/olpc: olpc-xo175-ec: Use SPI device ID data to bind device 2023-03-20 14:43:35 +01:00
surface platform/surface: aggregator: fix recv_buf() return value 2023-11-29 11:07:02 +02:00
x86 platform/x86/amd/pmf: Add support for PMF Policy Binary 2023-12-18 12:47:46 +01:00
Kconfig platform/mips: Adjust Kconfig to keep consistency 2022-12-08 11:51:52 +01:00
Makefile LoongArch: Add ACPI-based generic laptop driver 2022-10-12 16:36:20 +08:00