1========================== 2S3C24XX ARM Linux Overview 3========================== 4 5 6 7Introduction 8------------ 9 10 The Samsung S3C24XX range of ARM9 System-on-Chip CPUs are supported 11 by the 's3c2410' architecture of ARM Linux. Currently the S3C2410, 12 S3C2412, S3C2413, S3C2416, S3C2440, S3C2442, S3C2443 and S3C2450 devices 13 are supported. 14 15 Support for the S3C2400 and S3C24A0 series was never completed and the 16 corresponding code has been removed after a while. If someone wishes to 17 revive this effort, partial support can be retrieved from earlier Linux 18 versions. 19 20 The S3C2416 and S3C2450 devices are very similar and S3C2450 support is 21 included under the arch/arm/mach-s3c2416 directory. Note, while core 22 support for these SoCs is in, work on some of the extra peripherals 23 and extra interrupts is still ongoing. 24 25 26Configuration 27------------- 28 29 A generic S3C2410 configuration is provided, and can be used as the 30 default by `make s3c2410_defconfig`. This configuration has support 31 for all the machines, and the commonly used features on them. 32 33 Certain machines may have their own default configurations as well, 34 please check the machine specific documentation. 35 36 37Layout 38------ 39 40 The core support files are located in the platform code contained in 41 arch/arm/plat-s3c24xx with headers in include/asm-arm/plat-s3c24xx. 42 This directory should be kept to items shared between the platform 43 code (arch/arm/plat-s3c24xx) and the arch/arm/mach-s3c24* code. 44 45 Each cpu has a directory with the support files for it, and the 46 machines that carry the device. For example S3C2410 is contained 47 in arch/arm/mach-s3c2410 and S3C2440 in arch/arm/mach-s3c2440 48 49 Register, kernel and platform data definitions are held in the 50 arch/arm/mach-s3c2410 directory./include/mach 51 52arch/arm/plat-s3c24xx: 53 54 Files in here are either common to all the s3c24xx family, 55 or are common to only some of them with names to indicate this 56 status. The files that are not common to all are generally named 57 with the initial cpu they support in the series to ensure a short 58 name without any possibility of confusion with newer devices. 59 60 As an example, initially s3c244x would cover s3c2440 and s3c2442, but 61 with the s3c2443 which does not share many of the same drivers in 62 this directory, the name becomes invalid. We stick to s3c2440-<x> 63 to indicate a driver that is s3c2440 and s3c2442 compatible. 64 65 This does mean that to find the status of any given SoC, a number 66 of directories may need to be searched. 67 68 69Machines 70-------- 71 72 The currently supported machines are as follows: 73 74 Simtec Electronics EB2410ITX (BAST) 75 76 A general purpose development board, see EB2410ITX.txt for further 77 details 78 79 Simtec Electronics IM2440D20 (Osiris) 80 81 CPU Module from Simtec Electronics, with a S3C2440A CPU, nand flash 82 and a PCMCIA controller. 83 84 Samsung SMDK2410 85 86 Samsung's own development board, geared for PDA work. 87 88 Samsung/Aiji SMDK2412 89 90 The S3C2412 version of the SMDK2440. 91 92 Samsung/Aiji SMDK2413 93 94 The S3C2412 version of the SMDK2440. 95 96 Samsung/Meritech SMDK2440 97 98 The S3C2440 compatible version of the SMDK2440, which has the 99 option of an S3C2440 or S3C2442 CPU module. 100 101 Thorcom VR1000 102 103 Custom embedded board 104 105 HP IPAQ 1940 106 107 Handheld (IPAQ), available in several varieties 108 109 HP iPAQ rx3715 110 111 S3C2440 based IPAQ, with a number of variations depending on 112 features shipped. 113 114 Acer N30 115 116 A S3C2410 based PDA from Acer. There is a Wiki page at 117 http://handhelds.org/moin/moin.cgi/AcerN30Documentation . 118 119 AML M5900 120 121 American Microsystems' M5900 122 123 Nex Vision Nexcoder 124 Nex Vision Otom 125 126 Two machines by Nex Vision 127 128 129Adding New Machines 130------------------- 131 132 The architecture has been designed to support as many machines as can 133 be configured for it in one kernel build, and any future additions 134 should keep this in mind before altering items outside of their own 135 machine files. 136 137 Machine definitions should be kept in linux/arch/arm/mach-s3c2410, 138 and there are a number of examples that can be looked at. 139 140 Read the kernel patch submission policies as well as the 141 Documentation/arm directory before submitting patches. The 142 ARM kernel series is managed by Russell King, and has a patch system 143 located at http://www.arm.linux.org.uk/developer/patches/ 144 as well as mailing lists that can be found from the same site. 145 146 As a courtesy, please notify <ben-linux@fluff.org> of any new 147 machines or other modifications. 148 149 Any large scale modifications, or new drivers should be discussed 150 on the ARM kernel mailing list (linux-arm-kernel) before being 151 attempted. See http://www.arm.linux.org.uk/mailinglists/ for the 152 mailing list information. 153 154 155I2C 156--- 157 158 The hardware I2C core in the CPU is supported in single master 159 mode, and can be configured via platform data. 160 161 162RTC 163--- 164 165 Support for the onboard RTC unit, including alarm function. 166 167 This has recently been upgraded to use the new RTC core, 168 and the module has been renamed to rtc-s3c to fit in with 169 the new rtc naming scheme. 170 171 172Watchdog 173-------- 174 175 The onchip watchdog is available via the standard watchdog 176 interface. 177 178 179NAND 180---- 181 182 The current kernels now have support for the s3c2410 NAND 183 controller. If there are any problems the latest linux-mtd 184 code can be found from http://www.linux-mtd.infradead.org/ 185 186 For more information see Documentation/arm/samsung-s3c24xx/nand.rst 187 188 189SD/MMC 190------ 191 192 The SD/MMC hardware pre S3C2443 is supported in the current 193 kernel, the driver is drivers/mmc/host/s3cmci.c and supports 194 1 and 4 bit SD or MMC cards. 195 196 The SDIO behaviour of this driver has not been fully tested. There is no 197 current support for hardware SDIO interrupts. 198 199 200Serial 201------ 202 203 The s3c2410 serial driver provides support for the internal 204 serial ports. These devices appear as /dev/ttySAC0 through 3. 205 206 To create device nodes for these, use the following commands 207 208 mknod ttySAC0 c 204 64 209 mknod ttySAC1 c 204 65 210 mknod ttySAC2 c 204 66 211 212 213GPIO 214---- 215 216 The core contains support for manipulating the GPIO, see the 217 documentation in GPIO.txt in the same directory as this file. 218 219 Newer kernels carry GPIOLIB, and support is being moved towards 220 this with some of the older support in line to be removed. 221 222 As of v2.6.34, the move towards using gpiolib support is almost 223 complete, and very little of the old calls are left. 224 225 See Documentation/arm/samsung-s3c24xx/gpio.rst for the S3C24XX specific 226 support and Documentation/arm/samsung/gpio.rst for the core Samsung 227 implementation. 228 229 230Clock Management 231---------------- 232 233 The core provides the interface defined in the header file 234 include/asm-arm/hardware/clock.h, to allow control over the 235 various clock units 236 237 238Suspend to RAM 239-------------- 240 241 For boards that provide support for suspend to RAM, the 242 system can be placed into low power suspend. 243 244 See Suspend.txt for more information. 245 246 247SPI 248--- 249 250 SPI drivers are available for both the in-built hardware 251 (although there is no DMA support yet) and a generic 252 GPIO based solution. 253 254 255LEDs 256---- 257 258 There is support for GPIO based LEDs via a platform driver 259 in the LED subsystem. 260 261 262Platform Data 263------------- 264 265 Whenever a device has platform specific data that is specified 266 on a per-machine basis, care should be taken to ensure the 267 following: 268 269 1) that default data is not left in the device to confuse the 270 driver if a machine does not set it at startup 271 272 2) the data should (if possible) be marked as __initdata, 273 to ensure that the data is thrown away if the machine is 274 not the one currently in use. 275 276 The best way of doing this is to make a function that 277 kmalloc()s an area of memory, and copies the __initdata 278 and then sets the relevant device's platform data. Making 279 the function `__init` takes care of ensuring it is discarded 280 with the rest of the initialisation code:: 281 282 static __init void s3c24xx_xxx_set_platdata(struct xxx_data *pd) 283 { 284 struct s3c2410_xxx_mach_info *npd; 285 286 npd = kmalloc(sizeof(struct s3c2410_xxx_mach_info), GFP_KERNEL); 287 if (npd) { 288 memcpy(npd, pd, sizeof(struct s3c2410_xxx_mach_info)); 289 s3c_device_xxx.dev.platform_data = npd; 290 } else { 291 printk(KERN_ERR "no memory for xxx platform data\n"); 292 } 293 } 294 295 Note, since the code is marked as __init, it should not be 296 exported outside arch/arm/mach-s3c2410/, or exported to 297 modules via EXPORT_SYMBOL() and related functions. 298 299 300Port Contributors 301----------------- 302 303 Ben Dooks (BJD) 304 Vincent Sanders 305 Herbert Potzl 306 Arnaud Patard (RTP) 307 Roc Wu 308 Klaus Fetscher 309 Dimitry Andric 310 Shannon Holland 311 Guillaume Gourat (NexVision) 312 Christer Weinigel (wingel) (Acer N30) 313 Lucas Correia Villa Real (S3C2400 port) 314 315 316Document Author 317--------------- 318 319Ben Dooks, Copyright 2004-2006 Simtec Electronics 320