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2015-10-23Documentation: EXYNOS: Update bootloader interface on exynos542xKrzysztof Kozlowski
Update the documentation about: 1. Usage of PMU_SPARE2 register. Bootloaders on Exynos542x-based boards often use the register PMU_SPARE2 (0x908) in the same way as on Exynos3250: as a indicator the secondary CPU was booted on. The bootloader will set this value to non-zero, after sucessfull power up of secondary CPU. In the same time this booted CPU will stuck (spin) waiting for software reset. 2. Exynos542x entry address for secondary CPU boot up after system suspend (with MCPM enabled and in non-secure mode). See arch/arm/mach-exynos/mcpm-exynos.c for source code. Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Kukjin Kim <kgene@kernel.org>
2015-07-10Documentation: ARM: EXYNOS: Extend boot loader interface documentationKrzysztof Kozlowski
Extend the kernel-bootloader interface documentation with usage of register INFORM1 (0x0804) and different CPU resume address on Exynos542x family (with Multi-Cluster Power Management enabled). Additionally add glossary and reformat section titles. Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-06-08Documentation: ARM: EXYNOS: Describe boot loaders interfaceKrzysztof Kozlowski
Various boot loaders for Exynos based boards use certain memory addresses during booting for different purposes. Mostly this is one of following : 1. as a CPU boot address, 2. for storing magic cookie related to low power mode (AFTR, sleep). The document, based solely on kernel source code, tries to group the information scattered over different files. This would help in the future when adding support for new SoC or when extending features related to low power modes. Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>