There's currently two approaches being considered for how to allocate the
context buffer passed to PRM handlers:
1. The context buffer is allocated and populated in firmware. As such, the
FW converts all pointers internal to the buffer to virtual memory
addresses at the virtual address change event. A single context buffer
pointer is given to the OS via the PRM ACPI table and the OS converts
this single physical address to a virtual address when it passes the
context buffer as a pointer to PRM handlers.
2. The context buffer is allocated and populated in the OS. The OS gets
all the information needed to populate the context buffer from other
pre-existing resources (mainly physical addresses in the PRM ACPI
table). The OS converts all the physical addresses to virtual addresses,
allocates the context buffer instances, and fills in the information.
The OS passes the context buffer virtual address to PRM handlers.
The prior behavior was (1). The current POR behavior has moved to (2).
Until (2) is used more widely, it can be kept around with fairly minimal
overhead via a build flag in a few places.
So the default behavior is now (2) (the expected permanent behavior) with
(1) easily enabled by defining "ALLOCATE_CONTEXT_BUFFER_IN_FW" in the
compiler defined macros. A DSC define was added in PrmPkg.dsc to set this
compiler macro in the package build.
At some point in the future, all code (and some peripheral code)
surrounded with this build flag can be removed if (2) is fully
decided upon.
Cc: Andrew Fish <afish@apple.com>
Cc: Kang Gao <kang.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Benjamin You <benjamin.you@intel.com>
Cc: Liu Yun <yun.y.liu@intel.com>
Cc: Ankit Sinha <ankit.sinha@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Acked-by: Michael D Kinney <michael.d.kinney@intel.com>
Acked-by: Liming Gao <gaoliming@byosoft.com.cn>
Acked-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Ankit Sinha <ankit.sinha@intel.com>
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3812
This driver serves as a generic PRM configuration driver. Its primary
role is to prepare PRM resources published by PRM module configuration
libraries for OS runtime. As such, it locates all PRM Configuration
Protocol instances and consumes the information to ready those resources.
For example, set runtime memory attributes on MMIO ranges and convert
physical addresses to virtual addresses in PRM buffers.
Cc: Andrew Fish <afish@apple.com>
Cc: Kang Gao <kang.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Benjamin You <benjamin.you@intel.com>
Cc: Liu Yun <yun.y.liu@intel.com>
Cc: Ankit Sinha <ankit.sinha@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Acked-by: Michael D Kinney <michael.d.kinney@intel.com>
Acked-by: Liming Gao <gaoliming@byosoft.com.cn>
Acked-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Ankit Sinha <ankit.sinha@intel.com>
Michael Kubacki