doc/README.m68k

   1
   2 U-Boot for Motorola (or Freescale/NXP) ColdFire processors
   3
   4 ===============================================================================
   5 History
   6
   7 November 02, 2017       Angelo Dureghello <angelo@sysam.it>
   8 August   08, 2005       Jens Scharsig <esw@bus-elektronik.de>
   9                         MCF5282 implementation without preloader
  10 January  12, 2004       <josef.baumgartner@telex.de>
  11 ===============================================================================
  12
  13
  14 This file contains status information for the port of U-Boot to the
  15 Motorola ColdFire series of CPUs.
  16
  17
  18 1. Overview
  19
  20 The ColdFire instruction set is "assembly source" compatible but an evolution
  21 of the original 68000 instruction set. Some not much used instructions has
  22 been removed. The instructions are only 16, 32, or 48 bits long, a
  23 simplification compared to the 68000 series.
  24
  25 Bernhard Kuhn ported U-Boot 0.4.0 to the Motorola ColdFire architecture.
  26 The patches of Bernhard support the MCF5272 and MCF5282. A great disadvantage
  27 of these patches was that they needed a pre-bootloader to start U-Boot.
  28 Because of this, a new port was created which no longer needs a first stage
  29 booter.
  30
  31 Thanks mainly to Freescale but also to several other contributors, U-Boot now
  32 supports nearly the entire range of ColdFire processors and their related
  33 development boards.
  34
  35
  36 2. Supported CPU families
  37
  38 Please "make menuconfig" with ARCH=m68k, or check arch/m68k/cpu to see the
  39 currently supported processor and families.
  40
  41
  42 3. Supported boards
  43
  44 U-Boot supports actually more than 40 ColdFire based boards.
  45 Board configuration can be done trough include/configs/<boardname>.h but the
  46 current recommended method is to use the new and more friendly approach as
  47 the "make menuconfig" way, very similar to the Linux way.
  48
  49 To know details as memory map, build targets, default setup, etc, of a
  50 specific board please check:
  51
  52 include/configs/<boardname>.h
  53 and/or
  54 configs/<boardname>_defconfig
  55
  56 It is possible to build all ColdFire boards in a single command-line command,
  57 from u-boot root directory, as:
  58
  59 ./tools/buildman/buildman m68k
  60
  61
  62 3.1. Build U-Boot for a specific board
  63
  64 A bash script similar to the one below may be used:
  65
  66 #!/bin/bash
  67
  68 export CROSS_COMPILE=/opt/toolchains/m68k/gcc-4.9.0-nolibc/bin/m68k-linux-
  69
  70 board=M5475DFE
  71
  72 make distclean
  73 make ARCH=m68k ${board}_defconfig
  74 make ARCH=m68k KBUILD_VERBOSE=1
  75
  76
  77 4. Adopted toolchains
  78
  79 Please check:
  80 https://www.denx.de/wiki/U-Boot/ColdFireNotes
  81
  82
  83 5. ColdFire specific configuration options/settings
  84
  85
  86 5.1. Configuration to use a pre-loader
  87
  88 If U-Boot should be loaded to RAM and started by a pre-loader
  89 CONFIG_MONITOR_IS_IN_RAM must be defined. If it is defined the
  90 initial vector table and basic processor initialization will not
  91 be compiled in. The start address of U-Boot must be adjusted in
  92 the boards config header file (CONFIG_SYS_MONITOR_BASE) and Makefile
  93 (CONFIG_SYS_TEXT_BASE) to the load address.
  94
  95
  96 5.2 ColdFire CPU specific options/settings
  97
  98 To specify a CPU model, some defines shoudl be used, i.e.:
  99
 100 CONFIG_MCF52x2  -- defined for all MCF52x2 CPUs
 101 CONFIG_M5272    -- defined for all Motorola MCF5272 CPUs
 102
 103 Other options, generally set inside include/configs/<boardname>.h, they may
 104 apply to one or more cpu for the ColdFire family:
 105
 106 CONFIG_SYS_MBAR -- defines the base address of the MCF5272 configuration
 107                    registers
 108 CONFIG_SYS_ENET_BD_BASE
 109                 -- defines the base address of the FEC buffer descriptors
 110 CONFIG_SYS_SCR  -- defines the contents of the System Configuration Register
 111 CONFIG_SYS_SPR  -- defines the contents of the System Protection Register
 112 CONFIG_SYS_MFD  -- defines the PLL Multiplication Factor Divider
 113                    (see table 9-4 of MCF user manual)
 114 CONFIG_SYS_RFD  -- defines the PLL Reduce Frequency Devider
 115                    (see table 9-4 of MCF user manual)
 116 CONFIG_SYS_CSx_BASE
 117                 -- defines the base address of chip select x
 118 CONFIG_SYS_CSx_SIZE
 119                 -- defines the memory size (address range) of chip select x
 120 CONFIG_SYS_CSx_WIDTH
 121                 -- defines the bus with of chip select x
 122 CONFIG_SYS_CSx_MASK
 123                 -- defines the mask for the related chip select x
 124 CONFIG_SYS_CSx_RO
 125                 -- if set to 0 chip select x is read/write else chip select
 126                    is read only
 127 CONFIG_SYS_CSx_WS
 128                 -- defines the number of wait states  of chip select x
 129 CONFIG_SYS_CACHE_ICACR
 130 CONFIG_SYS_CACHE_DCACR
 131 CONFIG_SYS_CACHE_ACRX
 132                 -- cache-related registers config
 133 CONFIG_SYS_SDRAM_BASE
 134 CONFIG_SYS_SDRAM_SIZE
 135 CONFIG_SYS_SDRAM_BASEX
 136 CONFIG_SYS_SDRAM_CFG1
 137 CONFIG_SYS_SDRAM_CFG2
 138 CONFIG_SYS_SDRAM_CTRL
 139 CONFIG_SYS_SDRAM_MODE
 140 CONFIG_SYS_SDRAM_EMOD
 141                 -- SDRAM config for SDRAM controller-specific registers, please
 142                    see arch/m68k/cpu/<specific_cpu>/start.S files to see how
 143                    these options are used.
 144 CONFIG_MCFUART
 145                 -- defines enabling of ColdFire UART driver
 146 CONFIG_SYS_UART_PORT
 147                 -- defines the UART port to be used (only a single UART can be
 148                    actually enabled)
 149 CONFIG_SYS_SBFHDR_SIZE
 150                 -- size of the prepended SBF header, if any