[S] Change in coreboot[main]: soc/intel/xeon_sp: Use pre-processor to define ASL handler names

[Shuo Liu (Code Review)]

Shuo Liu has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/82133?usp=email )

Change subject: soc/intel/xeon_sp: Use pre-processor to define ASL handler names
......................................................................

soc/intel/xeon_sp: Use pre-processor to define ASL handler names

ASL handler name is 4-byte length ACPI name in the scope of _SB
which is not quite human readable easy to be mixed with other
methods under _SB.

Use pre-processor to define human readable handler names so that
they are well managed in _SB scope.

As to the parameter count of the ASL handler, which is limited to
8 by ACPI specification. It is encouraged to use up the Arg0-7
first. If the need argument exceeds 8, the last Arg (Arg7) could
be passed as a package of more parameters, which could be
extracted into unused local variables in the ASL handler codes.

Here is example,

ASL caller:

acpigen_write_return_namestr(ASL_HANDLER_PATH(AH_XXX));
/* passing the 1st-7th arg */
...
/* the 8th arg is a package, e.g. len = 3 */
acpigen_write_package(3);
acpigen_write_integer(...);
acpigen_write_integer(...);
acpigen_write_integer(...);
acpigen_write_package_end();

ASL callee:

Local0 = DeRefOf(Arg7[0])
Local1 = DeRefOf(Arg7[1])
Local2 = DeRefOf(Arg7[2])

TEST=Build and boot on intel/archercity CRB

Change-Id: I4134b275143d4f52622b864ed202252b2a150dae
Signed-off-by: Shuo Liu 
---
M src/soc/intel/xeon_sp/acpi.c
M src/soc/intel/xeon_sp/acpi/iiostack.asl
A src/soc/intel/xeon_sp/include/soc/asl_handler.h
3 files changed, 23 insertions(+), 7 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/33/82133/1

diff --git a/src/soc/intel/xeon_sp/acpi.c b/src/soc/intel/xeon_sp/acpi.c
index b513d25..7f04588 100644
--- a/src/soc/intel/xeon_sp/acpi.c
+++ b/src/soc/intel/xeon_sp/acpi.c
@@ -3,6 +3,7 @@
 #include <acpi/acpigen.h>
 #include <assert.h>
 #include <intelblocks/acpi.h>
+#include <soc/asl_handler.h>
 #include <soc/chip_common.h>
 #include <soc/pci_devs.h>
 #include <soc/util.h>
@@ -127,7 +128,7 @@
 {
    acpigen_write_method("_OSC", 4);

-	acpigen_write_return_namestr("\_SB.POSC");
+	acpigen_write_return_namestr(ASL_HANDLER_PATH(AH_PCIE_OSC));
    acpigen_emit_byte(ARG0_OP);
    acpigen_emit_byte(ARG1_OP);
    acpigen_emit_byte(ARG2_OP);
diff --git a/src/soc/intel/xeon_sp/acpi/iiostack.asl b/src/soc/intel/xeon_sp/acpi/iiostack.asl
index c943dd5..7cd8848 100644
--- a/src/soc/intel/xeon_sp/acpi/iiostack.asl
+++ b/src/soc/intel/xeon_sp/acpi/iiostack.asl
@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */

+#include <soc/asl_handler.h>
+
 #define PCI_HOST_BRIDGE_OSC_UUID     "33db4d5b-1ff7-401c-9657-7441c03dd766"
 #define CXL_HOST_BRIDGE_OSC_UUID     "68f2d50b-c469-4d8a-bd3d-941a103fd3fc"

@@ -16,7 +18,7 @@
 Scope (_SB)
 {
    /*
-	 * _SB.POSC - OSC handler for PCIe _OSC calls
+	 * AH_PCIE_OSC - ASL handler for PCIe _OSC calls
     *
     * Reference:
     * 6.2.11 in https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/06_Device_Configuration/Device...
@@ -30,9 +32,9 @@
     * Arg1 - Map to _OSC Arg1. An Integer containing a Revision ID of the buffer format
     * Arg2 - Map to _OSC Arg2. An Integer containing a count of entries in Arg3
     * Arg3 - Map to _OSC Arg3. A Buffer containing a list of DWORD capabilities
-	 * Arg4 - GrantedPCIeFeatures
-	 * Arg5 - IsCxlDomain
-	 * Arg6 - GrantedCxlFeatures
+	 * Arg4 - Extra parameter. GrantedPCIeFeatures
+	 * Arg5 - Extra parameter. IsCxlDomain
+	 * Arg6 - Extra parameter. GrantedCxlFeatures
     *
     * _OSC ASL Return Value:
     * A Buffer containing a list of capabilities
@@ -59,9 +61,8 @@
     * OTRC - Dword	Local7	0x10	CXL Features that OS requests for control
    */

-	Method (POSC, 7, NotSerialized)
+	Method (AH_PCIE_OSC, 7, NotSerialized)
    {
-
 #define OscArg0              Arg0
 #define OscArg1              Arg1
 #define OscArg2              Arg2
diff --git a/src/soc/intel/xeon_sp/include/soc/asl_handler.h b/src/soc/intel/xeon_sp/include/soc/asl_handler.h
new file mode 100644
index 0000000..ec90830
--- /dev/null
+++ b/src/soc/intel/xeon_sp/include/soc/asl_handler.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _SOC_ASL_HANDLER_H_
+#define _SOC_ASL_HANDLER_H_
+
+#define _TO_STR(name) #name
+#define TO_STR(name) _TO_STR(name)
+#define _ASL_HANDLER_PATH(scope, name) TO_STR(scope.name)
+#define ASL_HANDLER_PATH(name) _ASL_HANDLER_PATH(\_SB, name)
+
+/* ASL handler name list */
+#define AH_PCIE_OSC	H000
+
+#endif /* _SOC_ASL_HANDLER_H_ */