Platform/RPi: Make 3GB/4GB a runtime (BIOS setup) choice

Currently some OSes (e.g FreeBSD) can make full use of the maximum
4 GB of RAM a Raspberry Pi 4 can offer, whereas others (e.g. Linux)
must be restricted to only the first 3 GB.

Previously this was a compile-time choice chosen by PcdAcpiBasicMode,
and now we make it user-selectable. The default is a 3 GB limit.

Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c

@@ -11,11 +11,13 @@
 #include <Library/AcpiLib.h>
 #include <Library/HiiLib.h>
 #include <Library/DebugLib.h>
+#include <Library/DxeServicesTableLib.h>
 #include <Library/IoLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/UefiRuntimeServicesTableLib.h>
 #include <Library/DevicePathLib.h>
 #include <IndustryStandard/RpiMbox.h>
+#include <IndustryStandard/Bcm2711.h>
 #include <IndustryStandard/Bcm2836.h>
 #include <IndustryStandard/Bcm2836Gpio.h>
 #include <Library/GpioLib.h>
@@ -26,6 +28,8 @@ extern UINT8 ConfigDxeHiiBin[];
 extern UINT8 ConfigDxeStrings[];
 
 STATIC RASPBERRY_PI_FIRMWARE_PROTOCOL *mFwProtocol;
+STATIC UINT32 mModelFamily = 0;
+STATIC UINT32 mModelInstalledMB = 0;
 
 /*
  * The GUID inside Platform/RaspberryPi/RPi3/AcpiTables/AcpiTables.inf and
@@ -129,6 +133,24 @@ SetupVariables (
     PcdSet32 (PcdCustomCpuClock, PcdGet32 (PcdCustomCpuClock));
   }
 
+  if (mModelFamily >= 4 && mModelInstalledMB > 3 * 1024) {
+    /*
+     * This allows changing PcdRamLimitTo3GB in forms.
+     */
+    PcdSet32 (PcdRamMoreThan3GB, 1);
+
+    Size = sizeof (UINT32);
+    Status = gRT->GetVariable (L"RamLimitTo3GB",
+                               &gConfigDxeFormSetGuid,
+                               NULL, &Size, &Var32);
+    if (EFI_ERROR (Status)) {
+      PcdSet32 (PcdRamLimitTo3GB, PcdGet32 (PcdRamLimitTo3GB));
+    }
+  } else {
+    PcdSet32 (PcdRamMoreThan3GB, 0);
+    PcdSet32 (PcdRamLimitTo3GB, 0);
+  }
+
   Size = sizeof (UINT32);
   Status = gRT->GetVariable (L"SdIsArasan",
                   &gConfigDxeFormSetGuid,
@@ -224,7 +246,7 @@ ApplyVariables (
   UINT32 CpuClock = PcdGet32 (PcdCpuClock);
   UINT32 CustomCpuClock = PcdGet32 (PcdCustomCpuClock);
   UINT32 Rate = 0;
-  UINT32 ModelFamily = 0;
+  UINT64 SystemMemorySize;
 
   if (CpuClock != 0) {
     if (CpuClock == 2) {
@@ -258,15 +280,31 @@ ApplyVariables (
     DEBUG ((DEBUG_INFO, "Current CPU speed is %uHz\n", Rate));
   }
 
-  Status = mFwProtocol->GetModelFamily (&ModelFamily);
-  if (Status != EFI_SUCCESS) {
-    DEBUG ((DEBUG_ERROR, "Couldn't get the Raspberry Pi model family: %r\n", Status));
-  } else {
-    DEBUG ((DEBUG_INFO, "Current Raspberry Pi model family is 0x%x\n", ModelFamily));
-  }
+  if (mModelFamily >= 4 && PcdGet32 (PcdRamLimitTo3GB) == 0) {
+    /*
+     * Similar to how we compute the > 3 GB RAM segment's size in PlatformLib/
+     * RaspberryPiMem.c, with some overlap protection for the Bcm2xxx register
+     * spaces. This computation should also work for models with more than 4 GB
+     * RAM, if there ever exist ones.
+     */
+    SystemMemorySize = (UINT64)mModelInstalledMB * SIZE_1MB;
+    ASSERT (SystemMemorySize > 3UL * SIZE_1GB);
+    SystemMemorySize = MIN(SystemMemorySize, BCM2836_SOC_REGISTERS);
+    if (BCM2711_SOC_REGISTERS > 0) {
+      SystemMemorySize = MIN(SystemMemorySize, BCM2711_SOC_REGISTERS);
+    }
 
+    Status = gDS->AddMemorySpace (EfiGcdMemoryTypeSystemMemory, 3UL * BASE_1GB,
+                    SystemMemorySize - (3UL * SIZE_1GB),
+                    EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT | EFI_MEMORY_WB);
+    ASSERT_EFI_ERROR (Status);
+    Status = gDS->SetMemorySpaceAttributes (3UL * BASE_1GB,
+                    SystemMemorySize - (3UL * SIZE_1GB),
+                    EFI_MEMORY_WB);
+    ASSERT_EFI_ERROR (Status);
+  }
 
-  if (ModelFamily == 3) {
+  if (mModelFamily == 3) {
     /*
      * Pi 3: either Arasan or SdHost goes to SD card.
      *
@@ -316,7 +354,7 @@ ApplyVariables (
     GpioPinFuncSet (52, Gpio48Group);
     GpioPinFuncSet (53, Gpio48Group);
 
-  } else if (ModelFamily == 4) {
+  } else if (mModelFamily == 4) {
     /*
      * Pi 4: either Arasan or eMMC2 goes to SD card.
      */
@@ -352,7 +390,7 @@ ApplyVariables (
       GpioPinFuncSet (39, GPIO_FSEL_ALT3);
     }
   } else {
-    DEBUG ((DEBUG_ERROR, "Model Family %d not supported...\n", ModelFamily));
+    DEBUG ((DEBUG_ERROR, "Model Family %d not supported...\n", mModelFamily));
   }
 
   /*
@@ -400,6 +438,20 @@ ConfigInitialize (
     return Status;
   }
 
+  Status = mFwProtocol->GetModelFamily (&mModelFamily);
+  if (Status != EFI_SUCCESS) {
+    DEBUG ((DEBUG_ERROR, "Couldn't get the Raspberry Pi model family: %r\n", Status));
+  } else {
+    DEBUG ((DEBUG_INFO, "Current Raspberry Pi model family is %d\n", mModelFamily));
+  }
+
+  Status = mFwProtocol->GetModelInstalledMB (&mModelInstalledMB);
+  if (Status != EFI_SUCCESS) {
+    DEBUG ((DEBUG_ERROR, "Couldn't get the Raspberry Pi installed RAM size: %r\n", Status));
+  } else {
+    DEBUG ((DEBUG_INFO, "Current Raspberry Pi installed RAM size is %d MB\n", mModelInstalledMB));
+  }
+
   Status = SetupVariables ();
   if (Status != EFI_SUCCESS) {
     DEBUG ((DEBUG_ERROR, "Couldn't not setup NV vars: %r\n", Status));

Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.inf

@@ -33,6 +33,7 @@
   ArmPlatformPkg/ArmPlatformPkg.dec
   MdePkg/MdePkg.dec
   MdeModulePkg/MdeModulePkg.dec
+  Silicon/Broadcom/Bcm27xx/Bcm27xx.dec
   Silicon/Broadcom/Bcm283x/Bcm283x.dec
   Platform/RaspberryPi/RaspberryPi.dec
   EmbeddedPkg/EmbeddedPkg.dec
@@ -53,10 +54,11 @@
   gConfigDxeFormSetGuid
 
 [Protocols]
-  gRaspberryPiFirmwareProtocolGuid ## CONSUMES
+  gRaspberryPiFirmwareProtocolGuid      ## CONSUMES
   gRaspberryPiConfigAppliedProtocolGuid ## PRODUCES
 
 [Pcd]
+  gBcm27xxTokenSpaceGuid.PcdBcm27xxRegistersAddress
   gBcm283xTokenSpaceGuid.PcdBcm283xRegistersAddress
   gRaspberryPiTokenSpaceGuid.PcdCpuClock
   gRaspberryPiTokenSpaceGuid.PcdCustomCpuClock
@@ -70,8 +72,8 @@
   gRaspberryPiTokenSpaceGuid.PcdDebugShowUEFIExit
   gRaspberryPiTokenSpaceGuid.PcdDisplayEnableScaledVModes
   gRaspberryPiTokenSpaceGuid.PcdDisplayEnableSShot
-
-[FeaturePcd]
+  gRaspberryPiTokenSpaceGuid.PcdRamMoreThan3GB
+  gRaspberryPiTokenSpaceGuid.PcdRamLimitTo3GB
 
 [Depex]
   gPcdProtocolGuid AND gRaspberryPiFirmwareProtocolGuid

Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxeHii.uni

@@ -35,6 +35,17 @@
 #string STR_CHIPSET_SD_SDHOST        #language en-US "Broadcom SDHOST"
 #string STR_CHIPSET_SD_ARASAN        #language en-US "Arasan SDHCI"
 
+/*
+ * Advanced configuration.
+ */
+
+#string STR_ADVANCED_FORM_TITLE      #language en-US "Advanced Configuration"
+
+#string STR_ADVANCED_3GB_PROMPT      #language en-US "Limit RAM to 3 GB"
+#string STR_ADVANCED_3GB_HELP        #language en-US "OSes not supporting ACPI DMA constraints require a 3 GB limit or face broken xHCI USB"
+#string STR_ADVANCED_3GB_OFF         #language en-US "Disabled"
+#string STR_ADVANCED_3GB_ON          #language en-US "Enabled"
+
 /*
  * MMC/SD configuration.
  */

Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxeHii.vfr

@@ -73,6 +73,18 @@ typedef struct {
   UINT32 Routing;
 } CHIPSET_SD_VARSTORE_DATA;
 
+typedef struct {
+  /*
+   * Always set by ConfigDxe prior to HII init to reflect
+   * platform capability.
+   */
+  UINT32 Supported;
+} ADVANCED_RAM_MORE_THAN_3GB_VARSTORE_DATA;
+
+typedef struct {
+  UINT32 Enabled;
+} ADVANCED_RAM_LIMIT_TO_3GB_VARSTORE_DATA;
+
 typedef struct {
   /*
    * 0 - Don't disable multi-block.
@@ -140,6 +152,16 @@ formset
       name  = SdIsArasan,
       guid  = CONFIGDXE_FORM_SET_GUID;
 
+    efivarstore ADVANCED_RAM_MORE_THAN_3GB_VARSTORE_DATA,
+      attribute = EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_NON_VOLATILE,
+      name  = RamMoreThan3GB,
+      guid  = CONFIGDXE_FORM_SET_GUID;
+
+    efivarstore ADVANCED_RAM_LIMIT_TO_3GB_VARSTORE_DATA,
+      attribute = EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_NON_VOLATILE,
+      name  = RamLimitTo3GB,
+      guid  = CONFIGDXE_FORM_SET_GUID;
+
     efivarstore MMC_DISMULTI_VARSTORE_DATA,
       attribute = EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_NON_VOLATILE,
       name  = MmcDisableMulti,
@@ -193,6 +215,10 @@ formset
            prompt = STRING_TOKEN(STR_CHIPSET_FORM_TITLE),
            help = STRING_TOKEN(STR_NULL_STRING);
 
+        goto 0x1006,
+           prompt = STRING_TOKEN(STR_ADVANCED_FORM_TITLE),
+           help = STRING_TOKEN(STR_NULL_STRING);
+
         goto 0x1003,
            prompt = STRING_TOKEN(STR_MMC_FORM_TITLE),
            help = STRING_TOKEN(STR_NULL_STRING);
@@ -240,6 +266,21 @@ formset
         endoneof;
     endform;
 
+    form formid = 0x1006,
+        title  = STRING_TOKEN(STR_ADVANCED_FORM_TITLE);
+        subtitle text = STRING_TOKEN(STR_NULL_STRING);
+
+        grayoutif ideqval RamMoreThan3GB.Supported == 0;
+          oneof varid = RamLimitTo3GB.Enabled,
+              prompt      = STRING_TOKEN(STR_ADVANCED_3GB_PROMPT),
+              help        = STRING_TOKEN(STR_ADVANCED_3GB_HELP),
+              flags       = NUMERIC_SIZE_4 | INTERACTIVE | RESET_REQUIRED,
+              option text = STRING_TOKEN(STR_ADVANCED_3GB_OFF), value = 0, flags = DEFAULT;
+              option text = STRING_TOKEN(STR_ADVANCED_3GB_ON), value = 1, flags = 0;
+          endoneof;
+        endif;
+    endform;
+
     form formid = 0x1003,
         title  = STRING_TOKEN(STR_MMC_FORM_TITLE);
         subtitle text = STRING_TOKEN(STR_MMC_FORM_SUBTITLE);

Platform/RaspberryPi/RPi3/RPi3.dsc

@@ -439,6 +439,12 @@
   gRaspberryPiTokenSpaceGuid.PcdDisplayEnableScaledVModes|L"DisplayEnableScaledVModes"|gConfigDxeFormSetGuid|0x0|0xff
   gRaspberryPiTokenSpaceGuid.PcdDisplayEnableSShot|L"DisplayEnableSShot"|gConfigDxeFormSetGuid|0x0|1
 
+  #
+  # Supporting > 3GB of memory.
+  #
+  gRaspberryPiTokenSpaceGuid.PcdRamMoreThan3GB|L"RamMoreThan3GB"|gConfigDxeFormSetGuid|0x0|0
+  gRaspberryPiTokenSpaceGuid.PcdRamLimitTo3GB|L"RamLimitTo3GB"|gConfigDxeFormSetGuid|0x0|0
+
   #
   # Common UEFI ones.
   #

Platform/RaspberryPi/RPi4/RPi4.dsc

@@ -477,6 +477,12 @@
   gRaspberryPiTokenSpaceGuid.PcdDisplayEnableScaledVModes|L"DisplayEnableScaledVModes"|gConfigDxeFormSetGuid|0x0|0xff
   gRaspberryPiTokenSpaceGuid.PcdDisplayEnableSShot|L"DisplayEnableSShot"|gConfigDxeFormSetGuid|0x0|1
 
+  #
+  # Supporting > 3GB of memory.
+  #
+  gRaspberryPiTokenSpaceGuid.PcdRamMoreThan3GB|L"RamMoreThan3GB"|gConfigDxeFormSetGuid|0x0|0
+  gRaspberryPiTokenSpaceGuid.PcdRamLimitTo3GB|L"RamLimitTo3GB"|gConfigDxeFormSetGuid|0x0|1
+
   #
   # Common UEFI ones.
   #

Platform/RaspberryPi/RaspberryPi.dec

@@ -57,6 +57,8 @@
   gRaspberryPiTokenSpaceGuid.PcdCustomCpuClock|0|UINT32|0x00000016
   gRaspberryPiTokenSpaceGuid.PcdDisplayEnableScaledVModes|0|UINT8|0x00000017
   gRaspberryPiTokenSpaceGuid.PcdDisplayEnableSShot|0|UINT32|0x00000018
+  gRaspberryPiTokenSpaceGuid.PcdRamMoreThan3GB|0|UINT32|0x00000019
+  gRaspberryPiTokenSpaceGuid.PcdRamLimitTo3GB|0|UINT32|0x0000001A
 
 [PcdsFeatureFlag.common]
-  gRaspberryPiTokenSpaceGuid.PcdAcpiBasicMode|FALSE|BOOLEAN|0x00000019
+  gRaspberryPiTokenSpaceGuid.PcdAcpiBasicMode|FALSE|BOOLEAN|0x0000001B