This is really cool. Can be useful in a number of other places down the line (e.g. MAC address via device properties). Reviewed-by: Andrei Warkentin ________________________________ From: Jeremy Linton Sent: Monday, August 31, 2020 12:25 PM To: devel@edk2.groups.io Cc: Jeremy Linton ; Leif Lindholm ; Pete Batard ; Andrei Warkentin ; Ard Biesheuvel ; Samer El-Haj-Mahmoud Subject: [PATCH v4 2/6] Platform/RaspberryPi: Monitor ACPI Table installs Hook the ACPI table install sequence and add some basic conditional and AML NameOp update logic. If a table has a non-zero PCD declared that pcd is checked for a non-zero value before allowing the table to be installed. We also add a table of NameOp to PCD's which will be written into a DSDT/SSDT table as part of its install process. With this change we can declare something in ASL like: Name (VARN, 0x1234) and then add a table entry like: {"VARN", PcdToken(PcdVarn)} and the value of PcdVarn will replace the 0x1234 declared in the ASL above. Cc: Leif Lindholm Cc: Pete Batard Cc: Andrei Warkentin Cc: Ard Biesheuvel Cc: Samer El-Haj-Mahmoud Signed-off-by: Jeremy Linton Reviewed-by: Pete Batard <@pbatard> --- Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c | 153 ++++++++++++++++++++- 1 file changed, 152 insertions(+), 1 deletion(-) diff --git a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c index af54136ade..9e5d9734ca 100644 --- a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c +++ b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c @@ -568,6 +568,156 @@ ApplyVariables ( } +typedef struct { + CHAR8 Name[4]; + UINTN PcdToken; +} AML_NAME_OP_REPLACE; + +typedef struct { + UINT64 OemTableId; + UINTN PcdToken; + AML_NAME_OP_REPLACE *SdtNameOpReplace; +} NAMESPACE_TABLES; + +#define SSDT_PATTERN_LEN 5 +#define AML_NAMEOP_8 0x0A +#define AML_NAMEOP_16 0x0B +#define AML_NAMEOP_32 0x0C +#define AML_NAMEOP_STR 0x0D +/* + * Scan the given namespace table (DSDT/SSDT) for AML NameOps + * listed in the NameOpReplace structure. If one is found then + * update the value in the table from the specified Pcd + * + * This allows us to have conditionals in AML controlled + * by options in the BDS or detected during firmware bootstrap. + * We could extend this concept for strings/etc but due to len + * variations its probably easier to encode the strings + * in the ASL and pick the correct one based off a variable. + */ +STATIC VOID +UpdateSdtNameOps( + EFI_ACPI_DESCRIPTION_HEADER *AcpiTable, + AML_NAME_OP_REPLACE *NameOpReplace + ) +{ + UINTN Idx; + UINTN Index; + CHAR8 Pattern[SSDT_PATTERN_LEN]; + UINTN PcdVal; + UINT8 *SdtPtr; + UINT32 SdtSize; + + SdtSize = AcpiTable->Length; + + if (SdtSize > 0) { + SdtPtr = (UINT8*)AcpiTable; + + for (Idx = 0; NameOpReplace && NameOpReplace[Idx].PcdToken; Idx++) { + /* + * Do a single NameOp variable replacement these are of the + * form 08 XXXX SIZE VAL, where SIZE is 0A=byte, 0B=word, 0C=dword + * and XXXX is the name and VAL is the value + */ + Pattern[0] = 0x08; + Pattern[1] = NameOpReplace[Idx].Name[0]; + Pattern[2] = NameOpReplace[Idx].Name[1]; + Pattern[3] = NameOpReplace[Idx].Name[2]; + Pattern[4] = NameOpReplace[Idx].Name[3]; + + for (Index = 0; Index < (SdtSize - SSDT_PATTERN_LEN); Index++) { + if (CompareMem (SdtPtr + Index, Pattern, SSDT_PATTERN_LEN) == 0) { + PcdVal = LibPcdGet32 (NameOpReplace[Idx].PcdToken); + switch (SdtPtr[Index + SSDT_PATTERN_LEN]) { + case AML_NAMEOP_32: + SdtPtr[Index + SSDT_PATTERN_LEN + 4] = (PcdVal >> 24) & 0xFF; + SdtPtr[Index + SSDT_PATTERN_LEN + 3] = (PcdVal >> 16) & 0xFF; + // Fallthrough + case AML_NAMEOP_16: + SdtPtr[Index + SSDT_PATTERN_LEN + 2] = (PcdVal >> 8) & 0xFF; + // Fallthrough + case AML_NAMEOP_8: + SdtPtr[Index + SSDT_PATTERN_LEN + 1] = PcdVal & 0xFF; + break; + case 0: + case 1: + SdtPtr[Index + SSDT_PATTERN_LEN + 1] = !!PcdVal; + break; + case AML_NAMEOP_STR: + /* + * If the string val is added to the NameOpReplace, we can + * dynamically update things like _HID too as long as the + * string length matches. + */ + break; + } + break; + } + } + } + } +} + + +STATIC BOOLEAN +VerifyUpdateTable( + IN EFI_ACPI_DESCRIPTION_HEADER *AcpiHeader, + IN NAMESPACE_TABLES *SdtTable + ) +{ + BOOLEAN ret; + + ret = TRUE; + if (SdtTable->PcdToken && !LibPcdGet32 (SdtTable->PcdToken)) { + ret = FALSE; + } + if (ret && SdtTable->SdtNameOpReplace) { + UpdateSdtNameOps (AcpiHeader, SdtTable->SdtNameOpReplace); + } + + return ret; +} + + +STATIC NAMESPACE_TABLES SdtTables[] = { + { + SIGNATURE_64 ('R', 'P', 'I', 0, 0, 0, 0, 0), + 0, + NULL + }, + { } +}; + +/* + * Monitor the ACPI tables being installed and when + * a DSDT/SSDT is detected validate that we want to + * install it, and if so update any "NameOp" defined + * variables contained in the table from PCD values + */ +STATIC BOOLEAN +HandleDynamicNamespace ( + IN EFI_ACPI_DESCRIPTION_HEADER *AcpiHeader + ) +{ + UINTN Tables; + + switch (AcpiHeader->Signature) { + case SIGNATURE_32 ('D', 'S', 'D', 'T'): + case SIGNATURE_32 ('S', 'S', 'D', 'T'): + for (Tables = 0; SdtTables[Tables].OemTableId; Tables++) { + if (AcpiHeader->OemTableId == SdtTables[Tables].OemTableId) { + return VerifyUpdateTable (AcpiHeader, &SdtTables[Tables]); + } + } + DEBUG ((DEBUG_ERROR, "Found namespace table not in table list.\n")); + + return FALSE; + } + + return TRUE; +} + + EFI_STATUS EFIAPI ConfigInitialize ( @@ -618,7 +768,8 @@ ConfigInitialize ( if (PcdGet32 (PcdSystemTableMode) == SYSTEM_TABLE_MODE_ACPI || PcdGet32 (PcdSystemTableMode) == SYSTEM_TABLE_MODE_BOTH) { - Status = LocateAndInstallAcpiFromFv (&mAcpiTableFile); + Status = LocateAndInstallAcpiFromFvConditional (&mAcpiTableFile, + &HandleDynamicNamespace); ASSERT_EFI_ERROR (Status); } -- 2.13.7