From cefc7ca46235f01d5233e3abd4b79452af01d9e9 Mon Sep 17 00:00:00 2001 From: Erik Kaneda Date: Wed, 9 Jun 2021 20:41:52 -0700 Subject: ACPI: PRM: implement OperationRegion handler for the PlatformRtMechanism subtype Platform Runtime Mechanism (PRM) is a firmware interface that exposes a set of binary executables that can either be called from the AML interpreter or device drivers by bypassing the AML interpreter. This change implements the AML interpreter path. According to the specification [1], PRM services are listed in an ACPI table called the PRMT. This patch parses module and handler information listed in the PRMT and registers the PlatformRtMechanism OpRegion handler before ACPI tables are loaded. Each service is defined by a 16-byte GUID and called from writing a 26-byte ASL buffer containing the identifier to a FieldUnit object defined inside a PlatformRtMechanism OperationRegion. OperationRegion (PRMR, PlatformRtMechanism, 0, 26) Field (PRMR, BufferAcc, NoLock, Preserve) { PRMF, 208 // Write to this field to invoke the OperationRegion Handler } The 26-byte ASL buffer is defined as the following: Byte Offset Byte Length Description ============================================================= 0 1 PRM OperationRegion handler status 1 8 PRM service status 9 1 PRM command 10 16 PRM handler GUID The ASL caller fills out a 26-byte buffer containing the PRM command and the PRM handler GUID like so: /* Local0 is the PRM data buffer */ Local0 = buffer (26){} /* Create byte fields over the buffer */ CreateByteField (Local0, 0x9, CMD) CreateField (Local0, 0x50, 0x80, GUID) /* Fill in the command and data fields of the data buffer */ CMD = 0 // run command GUID = ToUUID("xxxx-xx-xxx-xxxx") /* * Invoke PRM service with an ID that matches GUID and save the * result. */ Local0 = (\_SB.PRMT.PRMF = Local0) Byte offset 0 - 8 are written by the handler as a status passed back to AML and used by ASL like so: /* Create byte fields over the buffer */ CreateByteField (Local0, 0x0, PSTA) CreateQWordField (Local0, 0x1, USTA) In this ASL code, PSTA contains a status from the OperationRegion and USTA contains a status from the PRM service. The 26-byte buffer is recieved by acpi_platformrt_space_handler. This handler will look at the command value and the handler guid and take the approperiate actions. Command value Action ===================================================================== 0 Run the PRM service indicated by the PRM handler GUID (bytes 10-26) 1 Prevent PRM runtime updates from happening to the service's parent module 2 Allow PRM updates from happening to the service's parent module This patch enables command value 0. Link: https://uefi.org/sites/default/files/resources/Platform%20Runtime%20Mechanism%20-%20with%20legal%20notice.pdf # [1] Signed-off-by: Erik Kaneda [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki --- include/linux/acpi.h | 1 + include/linux/prmt.h | 7 +++++++ 2 files changed, 8 insertions(+) create mode 100644 include/linux/prmt.h (limited to 'include/linux') diff --git a/include/linux/acpi.h b/include/linux/acpi.h index c60745f657e9..4c07ac22c6ba 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -132,6 +132,7 @@ enum acpi_address_range_id { union acpi_subtable_headers { struct acpi_subtable_header common; struct acpi_hmat_structure hmat; + struct acpi_prmt_module_header prmt; }; typedef int (*acpi_tbl_table_handler)(struct acpi_table_header *table); diff --git a/include/linux/prmt.h b/include/linux/prmt.h new file mode 100644 index 000000000000..24da8364b919 --- /dev/null +++ b/include/linux/prmt.h @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifdef CONFIG_ACPI_PRMT +void init_prmt(void); +#else +static inline void init_prmt(void) { } +#endif -- cgit v1.2.3-71-gd317 From 60faa8f1ac6e0588d53eb9a345adcdbcc96a8f47 Mon Sep 17 00:00:00 2001 From: Erik Kaneda Date: Wed, 9 Jun 2021 20:41:53 -0700 Subject: ACPI: Add \_SB._OSC bit for PRM Signed-off-by: Erik Kaneda Signed-off-by: Rafael J. Wysocki --- drivers/acpi/bus.c | 1 + include/linux/acpi.h | 1 + 2 files changed, 2 insertions(+) (limited to 'include/linux') diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index 3484497923d5..e8119a9eca28 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -305,6 +305,7 @@ static void acpi_bus_osc_negotiate_platform_control(void) capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_HOTPLUG_OST_SUPPORT; capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PCLPI_SUPPORT; + capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PRM_SUPPORT; #ifdef CONFIG_ARM64 capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_GENERIC_INITIATOR_SUPPORT; diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 4c07ac22c6ba..a618ba698a5c 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -551,6 +551,7 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context); #define OSC_SB_OSLPI_SUPPORT 0x00000100 #define OSC_SB_CPC_DIVERSE_HIGH_SUPPORT 0x00001000 #define OSC_SB_GENERIC_INITIATOR_SUPPORT 0x00002000 +#define OSC_SB_PRM_SUPPORT 0x00020000 #define OSC_SB_NATIVE_USB4_SUPPORT 0x00040000 extern bool osc_sb_apei_support_acked; -- cgit v1.2.3-71-gd317