This is a simple ACPI patch. I'm submitting a revised version to
linux-acpi per Rafael Wysocki and linux-cxl per Dan Williams.
The patch has been moved to the message body and a Signed-off-by tag has
been added. Thunderbird has added CRs so "patch -p1 -l" is needed. To
address other points:
Q. Dan Williams said: Yes, although I don't see much incremental benefit
to developers publishing a root only raw table... So, not opposed to the
patch, but I want to direct you to the sysfs representation of the CEDT
and CFMWS in /sys/bus/cxl/devices... Platform firmware CXL details are
modeled as "CXL root" objects in the /sys/bus/cxl device model.
A. The patch is being submitted in connection with work on a CXL bridge.
The developers would like to express appreciation for the "sysfs" point.
They find it useful to be able to do initialization through the table
but will look at the "sysfs" approach.
Q. Rafael J. Wysocki said: I'm not sure why the #ifdef is needed.
A. I reviewed cxl-next and decided to add the #ifdef to ensure that the
code would compile regardless of the direction that the codebase takes.
==== start of patch ====
Subject: Make ACPI subsystem provide CEDT table
Signed-off-by: Robert Kiraly <me@xxxxxxxxxxxxx>
This is a simple patch to the ACPI subsystem. The patch adds ACPI
_SIG_CEDT to table_sigs[] in "drivers/acpi/tables.c".
Presently, CXL code isn't able to make use of the CEDT table at
the initrd stage. Subsequent to the change, the CEDT table can be
used.
If a developer plans to use the CEDT table to program the CXL
ports, this change is needed. Otherwise, it isn't expected to
make a difference.
I certify compliance with Developer’s Certificate of Origin 1.1
as listed in:
https://www.kernel.org/doc/html/v4.10/process/submitting-patches.
html
--- linux-5.16.old/drivers/acpi/tables.c
+++ linux-5.16/drivers/acpi/tables.c
@@ -500,6 +500,9 @@
ACPI_SIG_WDDT, ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT,
ACPI_SIG_PSDT, ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT,
ACPI_SIG_IORT, ACPI_SIG_NFIT, ACPI_SIG_HMAT, ACPI_SIG_PPTT,
+#ifdef ACPI_SIG_CEDT
+ ACPI_SIG_CEDT,
+#endif
ACPI_SIG_NHLT };
#define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
==== end of patch ====
