1 ARM Linux 2.4 2 ============= 3 4 Please check ftp.arm.linux.org.uk:/pub/armlinux for latest updates. 5 6Compilation of kernel 7--------------------- 8 9 In order to compile ARM Linux, you will need a compiler capable of 10 generating ARM ELF code with GNU extensions. GCC 2.95.1 and EGCS 1.1.2 11 are good compilers. 12 13 To build ARM Linux natively, you shouldn't have to alter the ARCH = line 14 in the top level Makefile. However, if you don't have the ARM Linux ELF 15 tools installed as default, then you should change the CROSS_COMPILE 16 line as detailed below. 17 18 If you wish to cross-compile, then alter the following lines in the top 19 level make file: 20 21 ARCH = <whatever> 22 with 23 ARCH = arm 24 25 and 26 27 CROSS_COMPILE= 28 to 29 CROSS_COMPILE=<your-path-to-your-compiler-without-gcc> 30 eg. 31 CROSS_COMPILE=arm-linux- 32 33 Do a 'make config', followed by 'make dep', and finally 'make Image' to 34 build the kernel (arch/arm/boot/Image). A compressed image can be built 35 by doing a 'make zImage' instead of 'make Image'. 36 37 38Bug reports etc 39--------------- 40 41 Please send patches to the patch system. For more information, see 42 http://www.arm.linux.org.uk/patches/info.html Always include some 43 explanation as to what the patch does and why it is needed. 44 45 Bug reports should be sent to linux-arm-kernel@lists.arm.linux.org.uk, 46 or submitted through the web form at 47 http://www.arm.linux.org.uk/forms/solution.shtml 48 49 When sending bug reports, please ensure that they contain all relevant 50 information, eg. the kernel messages that were printed before/during 51 the problem, what you were doing, etc. 52 53 54Include files 55------------- 56 57 Several new include directories have been created under include/asm-arm, 58 which are there to reduce the clutter in the top-level directory. These 59 directories, and their purpose is listed below: 60 61 arch-* machine/platform specific header files 62 hardware driver-internal ARM specific data structures/definitions 63 mach descriptions of generic ARM to specific machine interfaces 64 proc-* processor dependent header files (currently only two 65 categories) 66 67 68Machine/Platform support 69------------------------ 70 71 The ARM tree contains support for a lot of different machine types. To 72 continue supporting these differences, it has become necessary to split 73 machine-specific parts by directory. For this, the machine category is 74 used to select which directories and files get included (we will use 75 $(MACHINE) to refer to the category) 76 77 To this end, we now have arch/arm/mach-$(MACHINE) directories which are 78 designed to house the non-driver files for a particular machine (eg, PCI, 79 memory management, architecture definitions etc). For all future 80 machines, there should be a corresponding include/asm-arm/arch-$(MACHINE) 81 directory. 82 83 84Modules 85------- 86 87 Although modularisation is supported (and required for the FP emulator), 88 each module on an ARM2/ARM250/ARM3 machine when is loaded will take 89 memory up to the next 32k boundary due to the size of the pages. 90 Therefore, modularisation on these machines really worth it? 91 92 However, ARM6 and up machines allow modules to take multiples of 4k, and 93 as such Acorn RiscPCs and other architectures using these processors can 94 make good use of modularisation. 95 96 97ADFS Image files 98---------------- 99 100 You can access image files on your ADFS partitions by mounting the ADFS 101 partition, and then using the loopback device driver. You must have 102 losetup installed. 103 104 Please note that the PCEmulator DOS partitions have a partition table at 105 the start, and as such, you will have to give '-o offset' to losetup. 106 107 108Request to developers 109--------------------- 110 111 When writing device drivers which include a separate assembler file, please 112 include it in with the C file, and not the arch/arm/lib directory. This 113 allows the driver to be compiled as a loadable module without requiring 114 half the code to be compiled into the kernel image. 115 116 In general, try to avoid using assembler unless it is really necessary. It 117 makes drivers far less easy to port to other hardware. 118 119 120ST506 hard drives 121----------------- 122 123 The ST506 hard drive controllers seem to be working fine (if a little 124 slowly). At the moment they will only work off the controllers on an 125 A4x0's motherboard, but for it to work off a Podule just requires 126 someone with a podule to add the addresses for the IRQ mask and the 127 HDC base to the source. 128 129 As of 31/3/96 it works with two drives (you should get the ADFS 130 *configure harddrive set to 2). I've got an internal 20MB and a great 131 big external 5.25" FH 64MB drive (who could ever want more :-) ). 132 133 I've just got 240K/s off it (a dd with bs=128k); thats about half of what 134 RiscOS gets; but it's a heck of a lot better than the 50K/s I was getting 135 last week :-) 136 137 Known bug: Drive data errors can cause a hang; including cases where 138 the controller has fixed the error using ECC. (Possibly ONLY 139 in that case...hmm). 140 141 1421772 Floppy 143----------- 144 This also seems to work OK, but hasn't been stressed much lately. It 145 hasn't got any code for disc change detection in there at the moment which 146 could be a bit of a problem! Suggestions on the correct way to do this 147 are welcome. 148 149 150Kernel entry (head-armv.S) 151-------------------------- 152 The initial entry into the kernel made via head-armv.S uses architecture 153 independent code. The architecture is selected by the value of 'r1' on 154 entry, which must be kept unique. You can register a new architecture 155 by mailing the following details to rmk@arm.linux.org.uk Please give 156 the mail a subject of 'Register new architecture': 157 158 Name: <name of your architecture> 159 ArchDir: <name of include/asm-arm/arch-* directory> 160 Type: <MACH_TYPE_* macro name> 161 Description: 162 <description of your architecture> 163 164 Please follow this format - it is an automated system. You should 165 receive a reply in short order. 166 167--- 168Russell King (26/01/2001) 169