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The pinmux code for the exynos5250 was all bundled into a single, large function which contained a switch statement that would set up the pins for different peripherals within the SOC. There was also a "flags" parameter, the meaning of which, if any, depended on which peripheral was being set up. There are several problems with that approach. First, the code is inefficient in both time and space. The caller knows which peripheral it wants to set up, but that information is encoded in a constant which has to be unpacked within the function before any action can be taken. If there were a function per peripheral, that information would be implicit. Also, the compiler and linker are forced to include the entire function with all its cases even if most of them are never called. If each peripheral was a function, the unused ones could be garbage collected. Second, it would be possible to try to set up a peripheral which that function doesn't know about, so there has to be additional error checking/handling. If each peripheral had a function, the fact that there was a function to call at all would imply that the call would be understood. Third, the flags parameter is fairly opaque, usually doesn't do anything, and sometimes has to have multiple values embedded in it. By having separate functions, you can have only the parameters you actually want, give them names that make sense, and pass in values directly. Fourth, having one giant function pretends to be a generic, portable API, but in reality, the only way it's useful is to call it with constants which are specific to a particular implementation of that API. It's highly unlikely that a bit of code will need to set up a peripheral but have no idea what that peripheral actually is. Call sights for the prior pinmux API have been updated. Also, pinmux initialization within the i2c driver was moved to be in the board setup code where it really probably belongs. The function block that implements the I2C controller may be shared between multiple SOCs (and in fact is), and those SOCs may have different pinmuxes (which they do). Other places this same sort of change can be made are the pinmux code for the 5420, and the clock configuration code for both the 5250 and the 5420. Change-Id: Ie9133a895e0dd861cb06a6d5f995b8770b6dc8cf Signed-off-by: Gabe Black <gabeblack@chromium.org> Reviewed-on: http://review.coreboot.org/3673 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
------------------------------------------------------------------------------- coreboot README ------------------------------------------------------------------------------- coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload. With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required. coreboot was formerly known as LinuxBIOS. Payloads -------- After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot. See http://www.coreboot.org/Payloads for a list of supported payloads. Supported Hardware ------------------ coreboot supports a wide range of chipsets, devices, and mainboards. For details please consult: * http://www.coreboot.org/Supported_Motherboards * http://www.coreboot.org/Supported_Chipsets_and_Devices Build Requirements ------------------ * gcc / g++ * make Optional: * doxygen (for generating/viewing documentation) * iasl (for targets with ACPI support) * gdb (for better debugging facilities on some targets) * ncurses (for 'make menuconfig') * flex and bison (for regenerating parsers) Building coreboot ----------------- Please consult http://www.coreboot.org/Build_HOWTO for details. Testing coreboot Without Modifying Your Hardware ------------------------------------------------ If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU. Please see http://www.coreboot.org/QEMU for details. Website and Mailing List ------------------------ Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website: http://www.coreboot.org You can contact us directly on the coreboot mailing list: http://www.coreboot.org/Mailinglist Copyright and License --------------------- The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details. coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details. This makes the resulting coreboot images licensed under the GPL, version 2.