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In U-boot, the directory structure, arch/$(ARCH)/cpu/$(CPU)/$(SOC)/ has been adopted except that $(CPU) is missing from some architectures and $(SOC) is missing from some CPUs. This structure did not fit very well in some cases. [1] AT91 AT91 SoC family have been developed across some ARM processor generations. Generally speaking, some IPs are often re-used in the same SoC family (same SoC vendor) even when the main processor is updated. As a result, a SoC-common directory is needed in the upper level. Currently, AT91 source files are placed as follows: arch/arm/cpu/arm920t/at91/* arch/arm/cpu/arm926ejs/at91/* arch/arm/cpu/armv7/at91/* arch/arm/cpu/at91-common/* Once directories are split, the motivation for refactorings across CPU directories is lost. Some files in arm920t/at91/ and arm926ejs/at91/ are so similar that they could be merged. [2] Tegra Tegra is a little bit special case where different CPUs are used for SPL and the main U-boot. To obey the arch/$(ARCH)/cpu/$(CPU)/$(SOC) structure, the source files must be placed across the CPUs, again SoC-common directory is necessary in the upper level. Moreover, there are several families in Tegra: Tegra20, Tegra30, Tegra114, Tegra124. Here again, the tegra-common directory is needed to contain commonly-used files. Tegra directories have been sprinkled in the directory structure. arch/arm/cpu/arm720t/tegra20 arch/arm/cpu/arm720t/tegra30 arch/arm/cpu/arm720t/tegra114 arch/arm/cpu/arm720t/tegra124 arch/arm/cpu/arm720t/tegra-common arch/arm/cpu/armv7/tegra20 arch/arm/cpu/armv7/tegra30 arch/arm/cpu/armv7/tegra114 arch/arm/cpu/armv7/tegra124 arch/arm/cpu/armv7/tegra-common arch/arm/cpu/tegra20-common arch/arm/cpu/tegra30-common arch/arm/cpu/tegra114-common arch/arm/cpu/tegra124-common arch/arm/cpu/tegra-common As you see, splitting SoC code by the CPU is not going well, especially for ARM. Why don't we collect SoC-specific files into a single place? A good example we can follow is Linux's arch/arm/mach-* structure. This item was discussed in the following thread: http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/188548/ Looks like I got some positive responses and we are almost ready to start this movement. This commit prepares arch/arm/Makefile for describing machdirs in it. After this commit, we can move SoC directory to arch/arm/mach-$(SOC) in simple steps although some cases such as AT91 and Tegra need more fixes. What we generally have to do is: [1] Move files arch/arm/cpu/$(CPU)/$(SOC)/* to arch/arm/mach-$(SOC)/* [2] Add machine entry into arch/arm/Makefile [3] Remove "obj-y += $(SOC)" from arch/arm/cpu/$(CPU)/Makefile [4] Fix the Kconfig file path in arch/arm/Kconfig [5] Modify MAINTAINERS if necessary Signed-off-by:
Masahiro Yamada <yamada.m@jp.panasonic.com>
In U-boot, the directory structure, arch/$(ARCH)/cpu/$(CPU)/$(SOC)/ has been adopted except that $(CPU) is missing from some architectures and $(SOC) is missing from some CPUs. This structure did not fit very well in some cases. [1] AT91 AT91 SoC family have been developed across some ARM processor generations. Generally speaking, some IPs are often re-used in the same SoC family (same SoC vendor) even when the main processor is updated. As a result, a SoC-common directory is needed in the upper level. Currently, AT91 source files are placed as follows: arch/arm/cpu/arm920t/at91/* arch/arm/cpu/arm926ejs/at91/* arch/arm/cpu/armv7/at91/* arch/arm/cpu/at91-common/* Once directories are split, the motivation for refactorings across CPU directories is lost. Some files in arm920t/at91/ and arm926ejs/at91/ are so similar that they could be merged. [2] Tegra Tegra is a little bit special case where different CPUs are used for SPL and the main U-boot. To obey the arch/$(ARCH)/cpu/$(CPU)/$(SOC) structure, the source files must be placed across the CPUs, again SoC-common directory is necessary in the upper level. Moreover, there are several families in Tegra: Tegra20, Tegra30, Tegra114, Tegra124. Here again, the tegra-common directory is needed to contain commonly-used files. Tegra directories have been sprinkled in the directory structure. arch/arm/cpu/arm720t/tegra20 arch/arm/cpu/arm720t/tegra30 arch/arm/cpu/arm720t/tegra114 arch/arm/cpu/arm720t/tegra124 arch/arm/cpu/arm720t/tegra-common arch/arm/cpu/armv7/tegra20 arch/arm/cpu/armv7/tegra30 arch/arm/cpu/armv7/tegra114 arch/arm/cpu/armv7/tegra124 arch/arm/cpu/armv7/tegra-common arch/arm/cpu/tegra20-common arch/arm/cpu/tegra30-common arch/arm/cpu/tegra114-common arch/arm/cpu/tegra124-common arch/arm/cpu/tegra-common As you see, splitting SoC code by the CPU is not going well, especially for ARM. Why don't we collect SoC-specific files into a single place? A good example we can follow is Linux's arch/arm/mach-* structure. This item was discussed in the following thread: http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/188548/ Looks like I got some positive responses and we are almost ready to start this movement. This commit prepares arch/arm/Makefile for describing machdirs in it. After this commit, we can move SoC directory to arch/arm/mach-$(SOC) in simple steps although some cases such as AT91 and Tegra need more fixes. What we generally have to do is: [1] Move files arch/arm/cpu/$(CPU)/$(SOC)/* to arch/arm/mach-$(SOC)/* [2] Add machine entry into arch/arm/Makefile [3] Remove "obj-y += $(SOC)" from arch/arm/cpu/$(CPU)/Makefile [4] Fix the Kconfig file path in arch/arm/Kconfig [5] Modify MAINTAINERS if necessary Signed-off-by:
