Documentation/arm/Samsung-S3C24XX/Overview.txt

   1                         S3C24XX ARM Linux Overview
   2                         ==========================
   3
   4
   5
   6 Introduction
   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
  25 Configuration
  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
  36 Layout
  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
  51 arch/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
  68 Machines
  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
 128 Adding 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
 154 I2C
 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
 161 RTC
 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
 171 Watchdog
 172 --------
 173
 174   The onchip watchdog is available via the standard watchdog
 175   interface.
 176
 177
 178 NAND
 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
 188 SD/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
 199 Serial
 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
 212 GPIO
 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
 229 Clock 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
 237 Suspend 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
 246 SPI
 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
 254 LEDs
 255 ----
 256
 257   There is support for GPIO based LEDs via a platform driver
 258   in the LED subsystem.
 259
 260
 261 Platform 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
 299 Port 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
 315 Document Author
 316 ---------------
 317
 318 Ben Dooks, Copyright 2004-2006 Simtec Electronics