ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibCTA9x4/CTA9x4Helper.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # ARM VE Entry point. Reset vector in FV header will brach to
   4 # _ModuleEntryPoint.
   5 #
   6 # We use crazy macros, like LoadConstantToReg, since Xcode assembler
   7 # does not support = assembly syntax for ldr.
   8 #
   9 #  Copyright (c) 2011, ARM Limited. All rights reserved.
  10 #
  11 #  This program and the accompanying materials
  12 #  are licensed and made available under the terms and conditions of the BSD License
  13 #  which accompanies this distribution.  The full text of the license may be found at
  14 #  http://opensource.org/licenses/bsd-license.php
  15 #
  16 #  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  17 #  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  18 #
  19 #------------------------------------------------------------------------------
  20
  21 #include <AsmMacroIoLib.h>
  22 #include <Base.h>
  23 #include <Library/PcdLib.h>
  24 #include <Library/ArmPlatformLib.h>
  25 #include <AutoGen.h>
  26
  27 #Start of Code section
  28 .text
  29 .align 3
  30
  31 GCC_ASM_EXPORT(ArmPlatformIsMemoryInitialized)
  32 GCC_ASM_EXPORT(ArmPlatformInitializeBootMemory)
  33 .extern ASM_PFX(InitializeSMC)
  34
  35 /**
  36   Called at the early stage of the Boot phase to know if the memory has already been initialized
  37
  38   Running the code from the reset vector does not mean we start from cold boot. In some case, we
  39   can go through this code with the memory already initialized.
  40   Because this function is called at the early stage, the implementation must not use the stack.
  41   Its implementation must probably done in assembly to ensure this requirement.
  42
  43   @return   Return the condition value into the 'Z' flag
  44
  45 **/
  46 ASM_PFX(ArmPlatformIsMemoryInitialized):
  47   // Check if the memory has been already mapped, if so skipped the memory initialization
  48   LoadConstantToReg (ARM_VE_SYS_CFGRW1_REG ,r0)
  49   ldr   r0, [r0, #0]
  50
  51   // 0x40000000 = Value of Physical Configuration Switch SW[0]
  52   and   r0, r0, #0x40000000
  53   tst   r0, #0x40000000
  54   bx    lr
  55
  56 /**
  57   Initialize the memory where the initial stacks will reside
  58
  59   This memory can contain the initial stacks (Secure and Secure Monitor stacks).
  60   In some platform, this region is already initialized and the implementation of this function can
  61   do nothing. This memory can also represent the Secure RAM.
  62   This function is called before the satck has been set up. Its implementation must ensure the stack
  63   pointer is not used (probably required to use assembly language)
  64
  65 **/
  66 ASM_PFX(ArmPlatformInitializeBootMemory):
  67   mov   r5, lr
  68   // Initialize PL354 SMC
  69   LoadConstantToReg (ARM_VE_SMC_CTRL_BASE, r1)
  70   LoadConstantToReg (ARM_VE_SMB_PERIPH_VRAM, r2)
  71   blx   ASM_PFX(InitializeSMC)
  72   bx    r5
  73
  74 .end