Documentation/arm/Samsung/Bootloader-interface.txt

   1       Interface between kernel and boot loaders on Exynos boards
   2       ==========================================================
   3
   4 Author: Krzysztof Kozlowski
   5 Date  : 6 June 2015
   6
   7 The document tries to describe currently used interface between Linux kernel
   8 and boot loaders on Samsung Exynos based boards. This is not a definition
   9 of interface but rather a description of existing state, a reference
  10 for information purpose only.
  11
  12 In the document "boot loader" means any of following: U-boot, proprietary
  13 SBOOT or any other firmware for ARMv7 and ARMv8 initializing the board before
  14 executing kernel.
  15
  16
  17 1. Non-Secure mode
  18
  19 Address:      sysram_ns_base_addr
  20 Offset        Value                                        Purpose
  21 =============================================================================
  22 0x08          exynos_cpu_resume_ns, mcpm_entry_point       System suspend
  23 0x0c          0x00000bad (Magic cookie)                    System suspend
  24 0x1c          exynos4_secondary_startup                    Secondary CPU boot
  25 0x1c + 4*cpu  exynos4_secondary_startup (Exynos4412)       Secondary CPU boot
  26 0x20          0xfcba0d10 (Magic cookie)                    AFTR
  27 0x24          exynos_cpu_resume_ns                         AFTR
  28 0x28 + 4*cpu  0x8 (Magic cookie, Exynos3250)               AFTR
  29
  30
  31 2. Secure mode
  32
  33 Address:      sysram_base_addr
  34 Offset        Value                                        Purpose
  35 =============================================================================
  36 0x00          exynos4_secondary_startup                    Secondary CPU boot
  37 0x04          exynos4_secondary_startup (Exynos542x)       Secondary CPU boot
  38 4*cpu         exynos4_secondary_startup (Exynos4412)       Secondary CPU boot
  39 0x20          exynos_cpu_resume (Exynos4210 r1.0)          AFTR
  40 0x24          0xfcba0d10 (Magic cookie, Exynos4210 r1.0)   AFTR
  41
  42 Address:      pmu_base_addr
  43 Offset        Value                                        Purpose
  44 =============================================================================
  45 0x0800        exynos_cpu_resume                            AFTR, suspend
  46 0x0800        mcpm_entry_point (Exynos542x with MCPM)      AFTR, suspend
  47 0x0804        0xfcba0d10 (Magic cookie)                    AFTR
  48 0x0804        0x00000bad (Magic cookie)                    System suspend
  49 0x0814        exynos4_secondary_startup (Exynos4210 r1.1)  Secondary CPU boot
  50 0x0818        0xfcba0d10 (Magic cookie, Exynos4210 r1.1)   AFTR
  51 0x081C        exynos_cpu_resume (Exynos4210 r1.1)          AFTR
  52
  53
  54 3. Other (regardless of secure/non-secure mode)
  55
  56 Address:      pmu_base_addr
  57 Offset        Value                           Purpose
  58 =============================================================================
  59 0x0908        Non-zero                        Secondary CPU boot up indicator
  60                                               on Exynos3250 and Exynos542x
  61
  62
  63 4. Glossary
  64
  65 AFTR - ARM Off Top Running, a low power mode, Cortex cores and many other
  66 modules are power gated, except the TOP modules
  67 MCPM - Multi-Cluster Power Management