| Porting UEFI to a ARM platform : | |
| -------------------------------- | |
| 1. Create the new platform directory under ArmPlatformPkg | |
| 2. Create its DSC and FDF files into this new directory. These files can be copied from ArmVExpress-CTA9x4.dsc and ArmVExpress-CTA9x4.fdf; and adapted following the requirement of your platform. | |
| 3. Set up the PCDs required by ArmPlatformPkg in your FDF or DSC files | |
| 4. Implement 'ArmPlatformLib' for your platform following the interface defined by ArmPlatformPkg\Include\Library\ArmPlatformLib.h. | |
| PCDs Description : | |
| ------------------- | |
| # Firmware Device / Volume | |
| gArmTokenSpaceGuid.PcdSecureFdBaseAddress : Base address of your Secure Firmware Device | |
| gArmTokenSpaceGuid.PcdSecureFdSize : Size in byte of your Secure Firmware Device. | |
| gArmTokenSpaceGuid.PcdFdBaseAddress : Base Address of your Non-Secure/Normal World Firmware Device. | |
| gArmTokenSpaceGuid.PcdFdSize : Size in bytes of your Non-Secure/Normal World Firmware Device | |
| # Stacks | |
| gArmPlatformTokenSpaceGuid.PcdCPUCoresSecStackBase : Base of Secure Stack for Secure World | |
| gArmPlatformTokenSpaceGuid.PcdCPUCoreSecPrimaryStackSize : Size of the stack for the Primary Core in Secure World | |
| gArmPlatformTokenSpaceGuid.PcdCPUCoreSecSecondaryStackSize : Size of the stack for the Secondary Cores in Secure World | |
| gArmPlatformTokenSpaceGuid.PcdCPUCoresSecMonStackBase : Base of Stack for Monitor World | |
| gArmPlatformTokenSpaceGuid.PcdCPUCoreSecMonStackSize : Size of the stack for each cores | |
| gArmPlatformTokenSpaceGuid.PcdCPUCoresStackBase : Base of SEC Stack for Normal World | |
| gArmPlatformTokenSpaceGuid.PcdCPUCorePrimaryStackSize : Size of the stack for the Primary Core | |
| gArmPlatformTokenSpaceGuid.PcdCPUCoreSecondaryStackSize : Size of the stack for the Secondary Core | |
| # CPU / Architectural controllers | |
| gArmTokenSpaceGuid.PcdGicDistributorBase : Base address of the Distributor of your General Interrupt Controller | |
| gArmTokenSpaceGuid.PcdGicInterruptInterfaceBase : Base address of the Interface of your General Interrupt Controller | |
| # Memory Regions | |
| gArmPlatformTokenSpaceGuid.PcdSystemMemoryUefiRegionSize : Size of the region reserve for PI & UEFI | |
| gArmTokenSpaceGuid.PcdSystemMemoryBase : Base Address of the System Memory (DRAM) | |
| gArmTokenSpaceGuid.PcdSystemMemorySize : Size of the System Memory (DRAM) | |
| # Features | |
| gArmPlatformTokenSpaceGuid.PcdSystemMemoryInitializeInSec : TRUE if System Memory initialized by the SEC phase | |
| gArmPlatformTokenSpaceGuid.PcdSendSgiToBringUpSecondaryCores : TRUE if the PrePi or PrePeiCore modules have to send an SGI to resume the excution of the secondary cores | |
| # Boot Manager | |
| gArmPlatformTokenSpaceGuid.PcdDefaultBootDescription : Description of the Default Boot Entry | |
| gArmPlatformTokenSpaceGuid.PcdDefaultBootDevicePath : DevicePath of the Default Boot Entry | |
| gArmPlatformTokenSpaceGuid.PcdDefaultBootArgument : Argument for the Default Boot Entry | |
| gArmPlatformTokenSpaceGuid.PcdDefaultBootType : Define the binary type of the Default Boot Entry (0=EFI application, 1=Linux kernel with ATAG support, 2=Linux Kernel with FDT support) | |
| gArmPlatformTokenSpaceGuid.PcdPlatformBootTimeOut : Timeout before booting on the Device Boot entry (by default the auto boot is skipped) | |
| gArmPlatformTokenSpaceGuid.PcdDefaultConInPaths : List of Device Path use for the Console Input | |
| gArmPlatformTokenSpaceGuid.PcdDefaultConOutPaths : List of Device Path use for the Console Output | |
| FAQ : | |
| ----- | |
| # When to use PrePi or PrePeiCore ? | |
| - PrePi: when the memory has already been initialized by the first stage boot loader | |
| Boot sequence: PlatformFirmware/PrePi/Dxe/Bds | |
| Example: Beagle Board | |
| - PrePeiCore: when the firmware is started from XIP memory and in Secure world. The PeiCore shadows the firmware itself in System Memory (DRAM) | |
| Boot sequence: Sec/PrePiCore/PeiCore/Dxe/Bds | |
| Example: ARM Versatile Express | |
| See: | |
| - ArmPlatformPkg/Documentation/ARM-EDK2-Overview.png | |
| - ArmPlatformPkg/Documentation/ArmPlatformLib-Full-Boot.png | |
| - ArmPlatformPkg/Documentation/ArmPlatformLib-2nd-Stage.png | |
| # What is the PcdStandalone | |
| gArmPlatformTokenSpaceGuid.PcdStandalone=FALSE is used on ARM Development Platforms during the development stage. | |
| To avoid to reflash the NOR Flash after each build, the SEC (in NOR Flash) intializes thd DRAM and wait until the Normal World firmware is copied into the DRAM. | |
| Copying the firmware in DRAM is much faster than reflashing the NOR Flash. It is also more convenient to debug the firmware form DRAM than NOR Flash (eg: use of software breakpoint) | |