linux/Documentation/arm/Samsung-S3C24XX/Overview.txt
<<
>>
Prefs
   1                        S3C24XX ARM Linux Overview
   2                        ==========================
   3
   4
   5
   6Introduction
   7------------
   8
   9  The Samsung S3C24XX range of ARM9 System-on-Chip CPUs are supported
  10  by the 's3c2410' architecture of ARM Linux. Currently the S3C2410,
  11  S3C2412, S3C2413, S3C2416, S3C2440, S3C2442, S3C2443 and S3C2450 devices
  12  are supported.
  13
  14  Support for the S3C2400 and S3C24A0 series was never completed and the
  15  corresponding code has been removed after a while.  If someone wishes to
  16  revive this effort, partial support can be retrieved from earlier Linux
  17  versions.
  18
  19  The S3C2416 and S3C2450 devices are very similar and S3C2450 support is
  20  included under the arch/arm/mach-s3c2416 directory. Note, whilst core
  21  support for these SoCs is in, work on some of the extra peripherals
  22  and extra interrupts is still ongoing.
  23
  24
  25Configuration
  26-------------
  27
  28  A generic S3C2410 configuration is provided, and can be used as the
  29  default by `make s3c2410_defconfig`. This configuration has support
  30  for all the machines, and the commonly used features on them.
  31
  32  Certain machines may have their own default configurations as well,
  33  please check the machine specific documentation.
  34
  35
  36Layout
  37------
  38
  39  The core support files are located in the platform code contained in
  40  arch/arm/plat-s3c24xx with headers in include/asm-arm/plat-s3c24xx.
  41  This directory should be kept to items shared between the platform
  42  code (arch/arm/plat-s3c24xx) and the arch/arm/mach-s3c24* code.
  43
  44  Each cpu has a directory with the support files for it, and the
  45  machines that carry the device. For example S3C2410 is contained
  46  in arch/arm/mach-s3c2410 and S3C2440 in arch/arm/mach-s3c2440
  47
  48  Register, kernel and platform data definitions are held in the
  49  arch/arm/mach-s3c2410 directory./include/mach
  50
  51arch/arm/plat-s3c24xx:
  52
  53  Files in here are either common to all the s3c24xx family,
  54  or are common to only some of them with names to indicate this
  55  status. The files that are not common to all are generally named
  56  with the initial cpu they support in the series to ensure a short
  57  name without any possibility of confusion with newer devices.
  58
  59  As an example, initially s3c244x would cover s3c2440 and s3c2442, but
  60  with the s3c2443 which does not share many of the same drivers in
  61  this directory, the name becomes invalid. We stick to s3c2440-<x>
  62  to indicate a driver that is s3c2440 and s3c2442 compatible.
  63
  64  This does mean that to find the status of any given SoC, a number
  65  of directories may need to be searched.
  66
  67
  68Machines
  69--------
  70
  71  The currently supported machines are as follows:
  72
  73  Simtec Electronics EB2410ITX (BAST)
  74
  75    A general purpose development board, see EB2410ITX.txt for further
  76    details
  77
  78  Simtec Electronics IM2440D20 (Osiris)
  79
  80    CPU Module from Simtec Electronics, with a S3C2440A CPU, nand flash
  81    and a PCMCIA controller.
  82
  83  Samsung SMDK2410
  84
  85    Samsung's own development board, geared for PDA work.
  86
  87  Samsung/Aiji SMDK2412
  88
  89    The S3C2412 version of the SMDK2440.
  90
  91  Samsung/Aiji SMDK2413
  92
  93    The S3C2412 version of the SMDK2440.
  94
  95  Samsung/Meritech SMDK2440
  96
  97    The S3C2440 compatible version of the SMDK2440, which has the
  98    option of an S3C2440 or S3C2442 CPU module.
  99
 100  Thorcom VR1000
 101
 102    Custom embedded board
 103
 104  HP IPAQ 1940
 105
 106    Handheld (IPAQ), available in several varieties
 107
 108  HP iPAQ rx3715
 109
 110    S3C2440 based IPAQ, with a number of variations depending on
 111    features shipped.
 112
 113  Acer N30
 114
 115    A S3C2410 based PDA from Acer.  There is a Wiki page at
 116    http://handhelds.org/moin/moin.cgi/AcerN30Documentation .
 117
 118  AML M5900
 119
 120    American Microsystems' M5900
 121
 122  Nex Vision Nexcoder
 123  Nex Vision Otom
 124
 125    Two machines by Nex Vision
 126
 127
 128Adding New Machines
 129-------------------
 130
 131  The architecture has been designed to support as many machines as can
 132  be configured for it in one kernel build, and any future additions
 133  should keep this in mind before altering items outside of their own
 134  machine files.
 135
 136  Machine definitions should be kept in linux/arch/arm/mach-s3c2410,
 137  and there are a number of examples that can be looked at.
 138
 139  Read the kernel patch submission policies as well as the
 140  Documentation/arm directory before submitting patches. The
 141  ARM kernel series is managed by Russell King, and has a patch system
 142  located at http://www.arm.linux.org.uk/developer/patches/
 143  as well as mailing lists that can be found from the same site.
 144
 145  As a courtesy, please notify <ben-linux@fluff.org> of any new
 146  machines or other modifications.
 147
 148  Any large scale modifications, or new drivers should be discussed
 149  on the ARM kernel mailing list (linux-arm-kernel) before being
 150  attempted. See http://www.arm.linux.org.uk/mailinglists/ for the
 151  mailing list information.
 152
 153
 154I2C
 155---
 156
 157  The hardware I2C core in the CPU is supported in single master
 158  mode, and can be configured via platform data.
 159
 160
 161RTC
 162---
 163
 164  Support for the onboard RTC unit, including alarm function.
 165
 166  This has recently been upgraded to use the new RTC core,
 167  and the module has been renamed to rtc-s3c to fit in with
 168  the new rtc naming scheme.
 169
 170
 171Watchdog
 172--------
 173
 174  The onchip watchdog is available via the standard watchdog
 175  interface.
 176
 177
 178NAND
 179----
 180
 181  The current kernels now have support for the s3c2410 NAND
 182  controller. If there are any problems the latest linux-mtd
 183  code can be found from http://www.linux-mtd.infradead.org/
 184
 185  For more information see Documentation/arm/Samsung-S3C24XX/NAND.txt
 186
 187
 188SD/MMC
 189------
 190
 191  The SD/MMC hardware pre S3C2443 is supported in the current
 192  kernel, the driver is drivers/mmc/host/s3cmci.c and supports
 193  1 and 4 bit SD or MMC cards.
 194
 195  The SDIO behaviour of this driver has not been fully tested. There is no
 196  current support for hardware SDIO interrupts.
 197
 198
 199Serial
 200------
 201
 202  The s3c2410 serial driver provides support for the internal
 203  serial ports. These devices appear as /dev/ttySAC0 through 3.
 204
 205  To create device nodes for these, use the following commands
 206
 207    mknod ttySAC0 c 204 64
 208    mknod ttySAC1 c 204 65
 209    mknod ttySAC2 c 204 66
 210
 211
 212GPIO
 213----
 214
 215  The core contains support for manipulating the GPIO, see the
 216  documentation in GPIO.txt in the same directory as this file.
 217
 218  Newer kernels carry GPIOLIB, and support is being moved towards
 219  this with some of the older support in line to be removed.
 220
 221  As of v2.6.34, the move towards using gpiolib support is almost
 222  complete, and very little of the old calls are left.
 223
 224  See Documentation/arm/Samsung-S3C24XX/GPIO.txt for the S3C24XX specific
 225  support and Documentation/arm/Samsung/GPIO.txt for the core Samsung
 226  implementation.
 227
 228
 229Clock Management
 230----------------
 231
 232  The core provides the interface defined in the header file
 233  include/asm-arm/hardware/clock.h, to allow control over the
 234  various clock units
 235
 236
 237Suspend to RAM
 238--------------
 239
 240  For boards that provide support for suspend to RAM, the
 241  system can be placed into low power suspend.
 242
 243  See Suspend.txt for more information.
 244
 245
 246SPI
 247---
 248
 249  SPI drivers are available for both the in-built hardware
 250  (although there is no DMA support yet) and a generic
 251  GPIO based solution.
 252
 253
 254LEDs
 255----
 256
 257  There is support for GPIO based LEDs via a platform driver
 258  in the LED subsystem.
 259
 260
 261Platform Data
 262-------------
 263
 264  Whenever a device has platform specific data that is specified
 265  on a per-machine basis, care should be taken to ensure the
 266  following:
 267
 268    1) that default data is not left in the device to confuse the
 269       driver if a machine does not set it at startup
 270
 271    2) the data should (if possible) be marked as __initdata,
 272       to ensure that the data is thrown away if the machine is
 273       not the one currently in use.
 274
 275       The best way of doing this is to make a function that
 276       kmalloc()s an area of memory, and copies the __initdata
 277       and then sets the relevant device's platform data. Making
 278       the function `__init` takes care of ensuring it is discarded
 279       with the rest of the initialisation code
 280
 281       static __init void s3c24xx_xxx_set_platdata(struct xxx_data *pd)
 282       {
 283           struct s3c2410_xxx_mach_info *npd;
 284
 285           npd = kmalloc(sizeof(struct s3c2410_xxx_mach_info), GFP_KERNEL);
 286           if (npd) {
 287              memcpy(npd, pd, sizeof(struct s3c2410_xxx_mach_info));
 288              s3c_device_xxx.dev.platform_data = npd;
 289           } else {
 290              printk(KERN_ERR "no memory for xxx platform data\n");
 291           }
 292        }
 293
 294        Note, since the code is marked as __init, it should not be
 295        exported outside arch/arm/mach-s3c2410/, or exported to
 296        modules via EXPORT_SYMBOL() and related functions.
 297
 298
 299Port Contributors
 300-----------------
 301
 302  Ben Dooks (BJD)
 303  Vincent Sanders
 304  Herbert Potzl
 305  Arnaud Patard (RTP)
 306  Roc Wu
 307  Klaus Fetscher
 308  Dimitry Andric
 309  Shannon Holland
 310  Guillaume Gourat (NexVision)
 311  Christer Weinigel (wingel) (Acer N30)
 312  Lucas Correia Villa Real (S3C2400 port)
 313
 314
 315Document Author
 316---------------
 317
 318Ben Dooks, Copyright 2004-2006 Simtec Electronics
 319