1 2 U-Boot for ARM Integrator Development Platforms 3 4 Peter Pearse, ARM Ltd. 5 peter.pearse (a] arm.com 6 www.arm.com 7 8 Manuals available from :- 9 http://www.arm.com/products/DevTools/Hardware_Platforms.html 10 11 Overview : 12 -------- 13 There are two Integrator variants - Integrator/AP and Integrator/CP. 14 Each may be fitted with a variety of core modules (CMs). 15 Each CM consists of a ARM processor core and associated hardware e.g 16 FPGA implementing various controllers and/or register 17 SSRAM 18 SDRAM 19 RAM controllers 20 clock generators etc. 21 CMs may be fitted with varying amounts of SDRAM using a DIMM socket. 22 23 Boot Methods : 24 ------------ 25 Integrator platforms can be configured to use U-Boot in at least three ways :- 26 a) Run ARM boot monitor, manually run U-Boot image from flash 27 b) Run ARM boot monitor, automatically run U-Boot image from flash 28 c) Run U-Boot image direct from flash. 29 30 In cases a) and b) the ARM boot monitor will have configured the CM and mapped 31 writeable memory to 0x00000000 in the Integrator address space. 32 U-Boot has to carry out minimal configration before standard code is run. 33 34 In case c) it may be necessary for U-Boot to perform CM dependent initialization. 35 36 Configuring U-Boot : 37 ------------------ 38 The makefile contains targets for Integrator platforms of both types 39 fitted with all current variants of CM. If these targets are to be used with 40 boot process c) above then CONFIG_INIT_CRITICAL may need to be defined to ensure 41 that the CM is correctly configured. 42 43 There are also targets independent of CM. These may not be suitable for 44 boot process c) above. They have been preserved for backward compatibility with 45 existing build processes. 46 47 Code Hierarchy Applied : 48 ---------------------- 49 Code specific to initialization of a particular ARM processor has been placed in 50 cpu/arm<>/start.S so that it may be used by other boards. 51 52 However, to avoid duplicating code through all processor files, a generic core 53 for ARM Integrator CMs has been added 54 55 arch/arm/cpu/arm_intcm 56 57 Otherwise. for example, the standard CM reset via the CM control register would 58 need placing in each CM processor file...... 59 60 Code specific to the initialization of the CM, rather than the cpu, and initialization 61 of the Integrator board itself, has been placed in 62 63 board/integrator<>/platform.S 64 board/integrator<>/integrator<>.c 65 66 Targets 67 ======= 68 The U-Boot make targets map to the available core modules as below. 69 70 Integrator/AP is no longer available from ARM. 71 Core modules marked ** are also no longer available. 72 73 ap720t_config ** CM720T 74 ap920t_config ** CM920T 75 ap926ejs_config Integrator Core Module for ARM926EJ-STM 76 ap946es_config Integrator Core Module for ARM946E-STM 77 cp920t_config ** CM920T 78 cp926ejs_config Integrator Core Module for ARM926EJ-STM 79 cp946es_config Integrator Core Module for ARM946E-STM 80 cp1136_config Integrator Core Module ARM1136JF-S TM 81 82 The final groups of targets are for core modules where no explicit cpu 83 code has yet been added to U-Boot i.e. they all use the same U-Boot binary 84 using the generic "arm_intcm" core: 85 86 ap966_config Integrator Core Module for ARM966E-S TM 87 ap922_config Integrator Core Module for ARM922T TM with ETM 88 ap922_XA10_config Integrator Core Module for ARM922T using Altera Excalibur 89 ap7_config ** CM7TDMI 90 integratorap_config 91 ap_config 92 93 94 cp966_config Integrator Core Module for ARM966E-S TM 95 cp922_config Integrator Core Module for ARM922T TM with ETM 96 cp922_XA10_config Integrator Core Module for ARM922T using Altera Excalibur 97 cp1026_config Integrator Core Module ARM1026EJ-S TM 98 integratorcp_config 99 cp_config 100 101 The Makefile targets call board/integrator<>/split_by_variant.sh 102 to configure various defines in include/configs/integrator<>.h 103 to indicate the core module & core configuration and ensure that 104 board/integrator<>/u-boot.lds loads the cpu object first in the U-Boot image. 105 106 ********************************* 107 Because of this mechanism 108 > make clean 109 must be run before each change in configuration 110 ********************************* 111
