ArmVirtPkg/PrePi: move DRAM discovery code into PrePi

[mirror_edk2.git] / ArmVirtPkg / PrePi / Arm / ModuleEntryPoint.S

diff --git a/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S b/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S
index eebf660acdb20f411a666b6ca8289740c96c45af..a918c191432e83ee1d91f625391f1e1b51cf4be2 100644 (file)
--- a/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S
+++ b/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S
@@ -148,3 +148,74 @@ _GetStackBase:
 \r
 _NeverReturn:\r
   b _NeverReturn\r
+\r
+ASM_PFX(ArmPlatformPeiBootAction):\r
+  //\r
+  // If we are booting from RAM using the Linux kernel boot protocol, r0 will\r
+  // point to the DTB image in memory. Otherwise, use the default value defined\r
+  // by the platform.\r
+  //\r
+  teq   r0, #0\r
+  bne   0f\r
+  LDRL  (r0, PcdGet64 (PcdDeviceTreeInitialBaseAddress))\r
+\r
+0:mov   r11, r14            // preserve LR\r
+  mov   r10, r0             // preserve DTB pointer\r
+  mov   r9, r1              // preserve base of image pointer\r
+\r
+  //\r
+  // The base of the runtime image has been preserved in r1. Check whether\r
+  // the expected magic number can be found in the header.\r
+  //\r
+  ldr   r8, .LArm32LinuxMagic\r
+  ldr   r7, [r1, #0x24]\r
+  cmp   r7, r8\r
+  bne   .Lout\r
+\r
+  //\r
+  //\r
+  // OK, so far so good. We have confirmed that we likely have a DTB and are\r
+  // booting via the ARM Linux boot protocol. Update the base-of-image PCD\r
+  // to the actual relocated value, and add the shift of PcdFdBaseAddress to\r
+  // PcdFvBaseAddress as well\r
+  //\r
+  ADRL  (r8, PcdGet64 (PcdFdBaseAddress))\r
+  ADRL  (r7, PcdGet64 (PcdFvBaseAddress))\r
+  ldr   r6, [r8]\r
+  ldr   r5, [r7]\r
+  sub   r5, r5, r6\r
+  add   r5, r5, r1\r
+  str   r1, [r8]\r
+  str   r5, [r7]\r
+\r
+  //\r
+  // Discover the memory size and offset from the DTB, and record in the\r
+  // respective PCDs. This will also return false if a corrupt DTB is\r
+  // encountered. Since we are calling a C function, use the window at the\r
+  // beginning of the FD image as a temp stack.\r
+  //\r
+  ADRL  (r1, PcdGet64 (PcdSystemMemoryBase))\r
+  ADRL  (r2, PcdGet64 (PcdSystemMemorySize))\r
+  mov   sp, r5\r
+  bl    FindMemnode\r
+  teq   r0, #0\r
+  beq   .Lout\r
+\r
+  //\r
+  // Copy the DTB to the slack space right after the 64 byte arm64/Linux style\r
+  // image header at the base of this image (defined in the FDF), and record the\r
+  // pointer in PcdDeviceTreeInitialBaseAddress.\r
+  //\r
+  ADRL  (r8, PcdGet64 (PcdDeviceTreeInitialBaseAddress))\r
+  add   r9, r9, #0x40\r
+  str   r9, [r8]\r
+\r
+  mov   r0, r9\r
+  mov   r1, r10\r
+  bl    CopyFdt\r
+\r
+.Lout:\r
+  bx    r11\r
+\r
+.LArm32LinuxMagic:\r
+  .byte   0x18, 0x28, 0x6f, 0x01\r