| Interface between kernel and boot loaders on Exynos boards |
| ========================================================== |
| |
| Author: Krzysztof Kozlowski |
| Date : 6 June 2015 |
| |
| The document tries to describe currently used interface between Linux kernel |
| and boot loaders on Samsung Exynos based boards. This is not a definition |
| of interface but rather a description of existing state, a reference |
| for information purpose only. |
| |
| In the document "boot loader" means any of following: U-boot, proprietary |
| SBOOT or any other firmware for ARMv7 and ARMv8 initializing the board before |
| executing kernel. |
| |
| |
| 1. Non-Secure mode |
| |
| Address: sysram_ns_base_addr |
| Offset Value Purpose |
| ============================================================================= |
| 0x08 exynos_cpu_resume_ns, mcpm_entry_point System suspend |
| 0x0c 0x00000bad (Magic cookie) System suspend |
| 0x1c exynos4_secondary_startup Secondary CPU boot |
| 0x1c + 4*cpu exynos4_secondary_startup (Exynos4412) Secondary CPU boot |
| 0x20 0xfcba0d10 (Magic cookie) AFTR |
| 0x24 exynos_cpu_resume_ns AFTR |
| 0x28 + 4*cpu 0x8 (Magic cookie, Exynos3250) AFTR |
| |
| |
| 2. Secure mode |
| |
| Address: sysram_base_addr |
| Offset Value Purpose |
| ============================================================================= |
| 0x00 exynos4_secondary_startup Secondary CPU boot |
| 0x04 exynos4_secondary_startup (Exynos542x) Secondary CPU boot |
| 4*cpu exynos4_secondary_startup (Exynos4412) Secondary CPU boot |
| 0x20 exynos_cpu_resume (Exynos4210 r1.0) AFTR |
| 0x24 0xfcba0d10 (Magic cookie, Exynos4210 r1.0) AFTR |
| |
| Address: pmu_base_addr |
| Offset Value Purpose |
| ============================================================================= |
| 0x0800 exynos_cpu_resume AFTR, suspend |
| 0x0800 mcpm_entry_point (Exynos542x with MCPM) AFTR, suspend |
| 0x0804 0xfcba0d10 (Magic cookie) AFTR |
| 0x0804 0x00000bad (Magic cookie) System suspend |
| 0x0814 exynos4_secondary_startup (Exynos4210 r1.1) Secondary CPU boot |
| 0x0818 0xfcba0d10 (Magic cookie, Exynos4210 r1.1) AFTR |
| 0x081C exynos_cpu_resume (Exynos4210 r1.1) AFTR |
| |
| |
| 3. Other (regardless of secure/non-secure mode) |
| |
| Address: pmu_base_addr |
| Offset Value Purpose |
| ============================================================================= |
| 0x0908 Non-zero Secondary CPU boot up indicator |
| on Exynos3250 and Exynos542x |
| |
| |
| 4. Glossary |
| |
| AFTR - ARM Off Top Running, a low power mode, Cortex cores and many other |
| modules are power gated, except the TOP modules |
| MCPM - Multi-Cluster Power Management |