Based on kernel version 4.16.1. Page generated on 2018-04-09 11:52 EST.
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