diff options
Diffstat (limited to 'doc/arch/m68k.rst')
| -rw-r--r-- | doc/arch/m68k.rst | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/doc/arch/m68k.rst b/doc/arch/m68k.rst new file mode 100644 index 0000000000..34b2593eb8 --- /dev/null +++ b/doc/arch/m68k.rst @@ -0,0 +1,170 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +M68K / ColdFire +=============== + +History +------- +* November 02, 2017 Angelo Dureghello <angelo@sysam.it> +* August 08, 2005 Jens Scharsig <esw@bus-elektronik.de> + MCF5282 implementation without preloader +* January 12, 2004 <josef.baumgartner@telex.de> + +This file contains status information for the port of U-Boot to the +Motorola ColdFire series of CPUs. + +Overview +-------- + +The ColdFire instruction set is "assembly source" compatible but an evolution +of the original 68000 instruction set. Some not much used instructions has +been removed. The instructions are only 16, 32, or 48 bits long, a +simplification compared to the 68000 series. + +Bernhard Kuhn ported U-Boot 0.4.0 to the Motorola ColdFire architecture. +The patches of Bernhard support the MCF5272 and MCF5282. A great disadvantage +of these patches was that they needed a pre-bootloader to start U-Boot. +Because of this, a new port was created which no longer needs a first stage +booter. + +Thanks mainly to Freescale but also to several other contributors, U-Boot now +supports nearly the entire range of ColdFire processors and their related +development boards. + + +Supported CPU families +---------------------- + +Please "make menuconfig" with ARCH=m68k, or check arch/m68k/cpu to see the +currently supported processor and families. + + +Supported boards +---------------- + +U-Boot supports actually more than 40 ColdFire based boards. +Board configuration can be done trough include/configs/<boardname>.h but the +current recommended method is to use the new and more friendly approach as +the "make menuconfig" way, very similar to the Linux way. + +To know details as memory map, build targets, default setup, etc, of a +specific board please check: + +* include/configs/<boardname>.h + +and/or + +* configs/<boardname>_defconfig + +It is possible to build all ColdFire boards in a single command-line command, +from u-boot root directory, as:: + + ./tools/buildman/buildman m68k + +Build U-Boot for a specific board +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +A bash script similar to the one below may be used: + +.. code-block:: shell + + #!/bin/bash + + export CROSS_COMPILE=/opt/toolchains/m68k/gcc-4.9.0-nolibc/bin/m68k-linux- + + board=M5475DFE + + make distclean + make ARCH=m68k ${board}_defconfig + make ARCH=m68k KBUILD_VERBOSE=1 + + +Adopted toolchains +------------------ + +Please check: +https://www.denx.de/wiki/U-Boot/ColdFireNotes + + +ColdFire specific configuration options/settings +------------------------------------------------ + +Configuration to use a pre-loader +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +If U-Boot should be loaded to RAM and started by a pre-loader +CONFIG_MONITOR_IS_IN_RAM must be defined. If it is defined the +initial vector table and basic processor initialization will not +be compiled in. The start address of U-Boot must be adjusted in +the boards config header file (CONFIG_SYS_MONITOR_BASE) and Makefile +(CONFIG_SYS_TEXT_BASE) to the load address. + +ColdFire CPU specific options/settings +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To specify a CPU model, some defines shoudl be used, i.e.: + +CONFIG_MCF52x2: + defined for all MCF52x2 CPUs +CONFIG_M5272: + defined for all Motorola MCF5272 CPUs + +Other options, generally set inside include/configs/<boardname>.h, they may +apply to one or more cpu for the ColdFire family: + +CONFIG_SYS_MBAR: + defines the base address of the MCF5272 configuration registers +CONFIG_SYS_ENET_BD_BASE: + defines the base address of the FEC buffer descriptors +CONFIG_SYS_SCR: + defines the contents of the System Configuration Register +CONFIG_SYS_SPR: + defines the contents of the System Protection Register +CONFIG_SYS_MFD: + defines the PLL Multiplication Factor Divider + (see table 9-4 of MCF user manual) +CONFIG_SYS_RFD: + defines the PLL Reduce Frequency Devider + (see table 9-4 of MCF user manual) +CONFIG_SYS_CSx_BASE: + defines the base address of chip select x +CONFIG_SYS_CSx_SIZE: + defines the memory size (address range) of chip select x +CONFIG_SYS_CSx_WIDTH: + defines the bus with of chip select x +CONFIG_SYS_CSx_MASK: + defines the mask for the related chip select x +CONFIG_SYS_CSx_RO: + if set to 0 chip select x is read/write else chip select is read only +CONFIG_SYS_CSx_WS: + defines the number of wait states of chip select x +CONFIG_SYS_CACHE_ICACR: + cache-related registers config +CONFIG_SYS_CACHE_DCACR: + cache-related registers config +CONFIG_SYS_CACHE_ACRX: + cache-related registers config +CONFIG_SYS_SDRAM_BASE: + SDRAM config for SDRAM controller-specific registers +CONFIG_SYS_SDRAM_SIZE: + SDRAM config for SDRAM controller-specific registers +CONFIG_SYS_SDRAM_BASEX: + SDRAM config for SDRAM controller-specific registers +CONFIG_SYS_SDRAM_CFG1: + SDRAM config for SDRAM controller-specific registers +CONFIG_SYS_SDRAM_CFG2: + SDRAM config for SDRAM controller-specific registers +CONFIG_SYS_SDRAM_CTRL: + SDRAM config for SDRAM controller-specific registers +CONFIG_SYS_SDRAM_MODE: + SDRAM config for SDRAM controller-specific registers +CONFIG_SYS_SDRAM_EMOD: + SDRAM config for SDRAM controller-specific registers, please + see arch/m68k/cpu/<specific_cpu>/start.S files to see how + these options are used. +CONFIG_MCFUART: + defines enabling of ColdFire UART driver +CONFIG_SYS_UART_PORT: + defines the UART port to be used (only a single UART can be actually enabled) +CONFIG_SYS_SBFHDR_SIZE: + size of the prepended SBF header, if any |