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 are in progress.
  15
  16   The S3C2416 and S3C2450 devices are very similar and S3C2450 support is
  17   included under the arch/arm/mach-s3c2416 directory. Note, whilst core
  18   support for these SoCs is in, work on some of the extra peripherals
  19   and extra interrupts is still ongoing.
  20
  21
  22 Configuration
  23 -------------
  24
  25   A generic S3C2410 configuration is provided, and can be used as the
  26   default by `make s3c2410_defconfig`. This configuration has support
  27   for all the machines, and the commonly used features on them.
  28
  29   Certain machines may have their own default configurations as well,
  30   please check the machine specific documentation.
  31
  32
  33 Layout
  34 ------
  35
  36   The core support files are located in the platform code contained in
  37   arch/arm/plat-s3c24xx with headers in include/asm-arm/plat-s3c24xx.
  38   This directory should be kept to items shared between the platform
  39   code (arch/arm/plat-s3c24xx) and the arch/arm/mach-s3c24* code.
  40
  41   Each cpu has a directory with the support files for it, and the
  42   machines that carry the device. For example S3C2410 is contained
  43   in arch/arm/mach-s3c2410 and S3C2440 in arch/arm/mach-s3c2440
  44
  45   Register, kernel and platform data definitions are held in the
  46   arch/arm/mach-s3c2410 directory./include/mach
  47
  48 arch/arm/plat-s3c24xx:
  49
  50   Files in here are either common to all the s3c24xx family,
  51   or are common to only some of them with names to indicate this
  52   status. The files that are not common to all are generally named
  53   with the initial cpu they support in the series to ensure a short
  54   name without any possibility of confusion with newer devices.
  55
  56   As an example, initially s3c244x would cover s3c2440 and s3c2442, but
  57   with the s3c2443 which does not share many of the same drivers in
  58   this directory, the name becomes invalid. We stick to s3c2440-<x>
  59   to indicate a driver that is s3c2440 and s3c2442 compatible.
  60
  61   This does mean that to find the status of any given SoC, a number
  62   of directories may need to be searched.
  63
  64
  65 Machines
  66 --------
  67
  68   The currently supported machines are as follows:
  69
  70   Simtec Electronics EB2410ITX (BAST)
  71
  72     A general purpose development board, see EB2410ITX.txt for further
  73     details
  74
  75   Simtec Electronics IM2440D20 (Osiris)
  76
  77     CPU Module from Simtec Electronics, with a S3C2440A CPU, nand flash
  78     and a PCMCIA controller.
  79
  80   Samsung SMDK2410
  81
  82     Samsung's own development board, geared for PDA work.
  83
  84   Samsung/Aiji SMDK2412
  85
  86     The S3C2412 version of the SMDK2440.
  87
  88   Samsung/Aiji SMDK2413
  89
  90     The S3C2412 version of the SMDK2440.
  91
  92   Samsung/Meritech SMDK2440
  93
  94     The S3C2440 compatible version of the SMDK2440, which has the
  95     option of an S3C2440 or S3C2442 CPU module.
  96
  97   Thorcom VR1000
  98
  99     Custom embedded board
 100
 101   HP IPAQ 1940
 102
 103     Handheld (IPAQ), available in several varieties
 104
 105   HP iPAQ rx3715
 106
 107     S3C2440 based IPAQ, with a number of variations depending on
 108     features shipped.
 109
 110   Acer N30
 111
 112     A S3C2410 based PDA from Acer.  There is a Wiki page at
 113     http://handhelds.org/moin/moin.cgi/AcerN30Documentation .
 114
 115   AML M5900
 116
 117     American Microsystems' M5900
 118
 119   Nex Vision Nexcoder
 120   Nex Vision Otom
 121
 122     Two machines by Nex Vision
 123
 124
 125 Adding New Machines
 126 -------------------
 127
 128   The architecture has been designed to support as many machines as can
 129   be configured for it in one kernel build, and any future additions
 130   should keep this in mind before altering items outside of their own
 131   machine files.
 132
 133   Machine definitions should be kept in linux/arch/arm/mach-s3c2410,
 134   and there are a number of examples that can be looked at.
 135
 136   Read the kernel patch submission policies as well as the
 137   Documentation/arm directory before submitting patches. The
 138   ARM kernel series is managed by Russell King, and has a patch system
 139   located at http://www.arm.linux.org.uk/developer/patches/
 140   as well as mailing lists that can be found from the same site.
 141
 142   As a courtesy, please notify <ben-linux@fluff.org> of any new
 143   machines or other modifications.
 144
 145   Any large scale modifications, or new drivers should be discussed
 146   on the ARM kernel mailing list (linux-arm-kernel) before being
 147   attempted. See http://www.arm.linux.org.uk/mailinglists/ for the
 148   mailing list information.
 149
 150
 151 I2C
 152 ---
 153
 154   The hardware I2C core in the CPU is supported in single master
 155   mode, and can be configured via platform data.
 156
 157
 158 RTC
 159 ---
 160
 161   Support for the onboard RTC unit, including alarm function.
 162
 163   This has recently been upgraded to use the new RTC core,
 164   and the module has been renamed to rtc-s3c to fit in with
 165   the new rtc naming scheme.
 166
 167
 168 Watchdog
 169 --------
 170
 171   The onchip watchdog is available via the standard watchdog
 172   interface.
 173
 174
 175 NAND
 176 ----
 177
 178   The current kernels now have support for the s3c2410 NAND
 179   controller. If there are any problems the latest linux-mtd
 180   code can be found from http://www.linux-mtd.infradead.org/
 181
 182   For more information see Documentation/arm/Samsung-S3C24XX/NAND.txt
 183
 184
 185 SD/MMC
 186 ------
 187
 188   The SD/MMC hardware pre S3C2443 is supported in the current
 189   kernel, the driver is drivers/mmc/host/s3cmci.c and supports
 190   1 and 4 bit SD or MMC cards.
 191
 192   The SDIO behaviour of this driver has not been fully tested. There is no
 193   current support for hardware SDIO interrupts.
 194
 195
 196 Serial
 197 ------
 198
 199   The s3c2410 serial driver provides support for the internal
 200   serial ports. These devices appear as /dev/ttySAC0 through 3.
 201
 202   To create device nodes for these, use the following commands
 203
 204     mknod ttySAC0 c 204 64
 205     mknod ttySAC1 c 204 65
 206     mknod ttySAC2 c 204 66
 207
 208
 209 GPIO
 210 ----
 211
 212   The core contains support for manipulating the GPIO, see the
 213   documentation in GPIO.txt in the same directory as this file.
 214
 215   Newer kernels carry GPIOLIB, and support is being moved towards
 216   this with some of the older support in line to be removed.
 217
 218   As of v2.6.34, the move towards using gpiolib support is almost
 219   complete, and very little of the old calls are left.
 220
 221   See Documentation/arm/Samsung-S3C24XX/GPIO.txt for the S3C24XX specific
 222   support and Documentation/arm/Samsung/GPIO.txt for the core Samsung
 223   implementation.
 224
 225
 226 Clock Management
 227 ----------------
 228
 229   The core provides the interface defined in the header file
 230   include/asm-arm/hardware/clock.h, to allow control over the
 231   various clock units
 232
 233
 234 Suspend to RAM
 235 --------------
 236
 237   For boards that provide support for suspend to RAM, the
 238   system can be placed into low power suspend.
 239
 240   See Suspend.txt for more information.
 241
 242
 243 SPI
 244 ---
 245
 246   SPI drivers are available for both the in-built hardware
 247   (although there is no DMA support yet) and a generic
 248   GPIO based solution.
 249
 250
 251 LEDs
 252 ----
 253
 254   There is support for GPIO based LEDs via a platform driver
 255   in the LED subsystem.
 256
 257
 258 Platform Data
 259 -------------
 260
 261   Whenever a device has platform specific data that is specified
 262   on a per-machine basis, care should be taken to ensure the
 263   following:
 264
 265     1) that default data is not left in the device to confuse the
 266        driver if a machine does not set it at startup
 267
 268     2) the data should (if possible) be marked as __initdata,
 269        to ensure that the data is thrown away if the machine is
 270        not the one currently in use.
 271
 272        The best way of doing this is to make a function that
 273        kmalloc()s an area of memory, and copies the __initdata
 274        and then sets the relevant device's platform data. Making
 275        the function `__init` takes care of ensuring it is discarded
 276        with the rest of the initialisation code
 277
 278        static __init void s3c24xx_xxx_set_platdata(struct xxx_data *pd)
 279        {
 280            struct s3c2410_xxx_mach_info *npd;
 281
 282            npd = kmalloc(sizeof(struct s3c2410_xxx_mach_info), GFP_KERNEL);
 283            if (npd) {
 284               memcpy(npd, pd, sizeof(struct s3c2410_xxx_mach_info));
 285               s3c_device_xxx.dev.platform_data = npd;
 286            } else {
 287               printk(KERN_ERR "no memory for xxx platform data\n");
 288            }
 289         }
 290
 291         Note, since the code is marked as __init, it should not be
 292         exported outside arch/arm/mach-s3c2410/, or exported to
 293         modules via EXPORT_SYMBOL() and related functions.
 294
 295
 296 Port Contributors
 297 -----------------
 298
 299   Ben Dooks (BJD)
 300   Vincent Sanders
 301   Herbert Potzl
 302   Arnaud Patard (RTP)
 303   Roc Wu
 304   Klaus Fetscher
 305   Dimitry Andric
 306   Shannon Holland
 307   Guillaume Gourat (NexVision)
 308   Christer Weinigel (wingel) (Acer N30)
 309   Lucas Correia Villa Real (S3C2400 port)
 310
 311
 312 Document Author
 313 ---------------
 314
 315 Ben Dooks, Copyright 2004-2006 Simtec Electronics