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Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/Documentation/arm/Samsung/Bootloader-interface.txt b/Documentation/arm/Samsung/Bootloader-interface.txt
new file mode 100644
index 0000000..ed494ac
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+ 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