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Diffstat (limited to 'kernel/Documentation/arm/Samsung')
| -rw-r--r-- | kernel/Documentation/arm/Samsung/Bootloader-interface.txt | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/kernel/Documentation/arm/Samsung/Bootloader-interface.txt b/kernel/Documentation/arm/Samsung/Bootloader-interface.txt new file mode 100644 index 000000000..ed494ac0b --- /dev/null +++ b/kernel/Documentation/arm/Samsung/Bootloader-interface.txt @@ -0,0 +1,67 @@ + 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 |