S3C24XX ARM Linux Overview ========================== Introduction ------------ The Samsung S3C24XX range of ARM9 System-on-Chip CPUs are supported by the 's3c2410' architecture of ARM Linux. Currently the S3C2410 and the S3C2440 are supported CPUs. Support for the S3C2400 series is in progress. Configuration ------------- A generic S3C2410 configuration is provided, and can be used as the default by `make s3c2410_defconfig`. This configuration has support for all the machines, and the commonly used features on them. Certain machines may have their own default configurations as well, please check the machine specific documentation. Machines -------- The currently supported machines are as follows: Simtec Electronics EB2410ITX (BAST) A general purpose development board, see EB2410ITX.txt for further details Simtec Electronics IM2440D20 (Osiris) CPU Module from Simtec Electronics, with a S3C2440A CPU, nand flash and a PCMCIA controller. Samsung SMDK2410 Samsung's own development board, geared for PDA work. Samsung/Meritech SMDK2440 The S3C2440 compatible version of the SMDK2440 Thorcom VR1000 Custom embedded board HP IPAQ 1940 Handheld (IPAQ), available in several varieties HP iPAQ rx3715 S3C2440 based IPAQ, with a number of variations depending on features shipped. Acer N30 A S3C2410 based PDA from Acer. There is a Wiki page at http://handhelds.org/moin/moin.cgi/AcerN30Documentation . Adding New Machines ------------------- The archicture has been designed to support as many machines as can be configured for it in one kernel build, and any future additions should keep this in mind before altering items outside of their own machine files. Machine definitions should be kept in linux/arch/arm/mach-s3c2410, and there are a number of examples that can be looked at. Read the kernel patch submission policies as well as the Documentation/arm directory before submitting patches. The ARM kernel series is managed by Russell King, and has a patch system located at http://www.arm.linux.org.uk/developer/patches/ as well as mailing lists that can be found from the same site. As a courtesy, please notify of any new machines or other modifications. Any large scale modifications, or new drivers should be discussed on the ARM kernel mailing list (linux-arm-kernel) before being attempted. See http://www.arm.linux.org.uk/mailinglists/ for the mailing list information. I2C --- The hardware I2C core in the CPU is supported in single master mode, and can be configured via platform data. RTC --- Support for the onboard RTC unit, including alarm function. Watchdog -------- The onchip watchdog is available via the standard watchdog interface. NAND ---- The current kernels now have support for the s3c2410 NAND controller. If there are any problems the latest linux-mtd CVS can be found from http://www.linux-mtd.infradead.org/ Serial ------ The s3c2410 serial driver provides support for the internal serial ports. These devices appear as /dev/ttySAC0 through 3. To create device nodes for these, use the following commands mknod ttySAC0 c 204 64 mknod ttySAC1 c 204 65 mknod ttySAC2 c 204 66 GPIO ---- The core contains support for manipulating the GPIO, see the documentation in GPIO.txt in the same directory as this file. Clock Management ---------------- The core provides the interface defined in the header file include/asm-arm/hardware/clock.h, to allow control over the various clock units Suspend to RAM -------------- For boards that provide support for suspend to RAM, the system can be placed into low power suspend. See Suspend.txt for more information. Platform Data ------------- Whenever a device has platform specific data that is specified on a per-machine basis, care should be taken to ensure the following: 1) that default data is not left in the device to confuse the driver if a machine does not set it at startup 2) the data should (if possible) be marked as __initdata, to ensure that the data is thrown away if the machine is not the one currently in use. The best way of doing this is to make a function that kmalloc()s an area of memory, and copies the __initdata and then sets the relevant device's platform data. Making the function `__init` takes care of ensuring it is discarded with the rest of the initialisation code static __init void s3c24xx_xxx_set_platdata(struct xxx_data *pd) { struct s3c2410_xxx_mach_info *npd; npd = kmalloc(sizeof(struct s3c2410_xxx_mach_info), GFP_KERNEL); if (npd) { memcpy(npd, pd, sizeof(struct s3c2410_xxx_mach_info)); s3c_device_xxx.dev.platform_data = npd; } else { printk(KERN_ERR "no memory for xxx platform data\n"); } } Note, since the code is marked as __init, it should not be exported outside arch/arm/mach-s3c2410/, or exported to modules via EXPORT_SYMBOL() and related functions. Port Contributors ----------------- Ben Dooks (BJD) Vincent Sanders Herbert Potzl Arnaud Patard (RTP) Roc Wu Klaus Fetscher Dimitry Andric Shannon Holland Guillaume Gourat (NexVision) Christer Weinigel (wingel) (Acer N30) Lucas Correia Villa Real (S3C2400 port) Document Changes ---------------- 05 Sep 2004 - BJD - Added Document Changes section 05 Sep 2004 - BJD - Added Klaus Fetscher to list of contributors 25 Oct 2004 - BJD - Added Dimitry Andric to list of contributors 25 Oct 2004 - BJD - Updated the MTD from the 2.6.9 merge 21 Jan 2005 - BJD - Added rx3715, added Shannon to contributors 10 Feb 2005 - BJD - Added Guillaume Gourat to contributors 02 Mar 2005 - BJD - Added SMDK2440 to list of machines 06 Mar 2005 - BJD - Added Christer Weinigel 08 Mar 2005 - BJD - Added LCVR to list of people, updated introduction 08 Mar 2005 - BJD - Added section on adding machines 09 Sep 2005 - BJD - Added section on platform data 11 Feb 2006 - BJD - Added I2C, RTC and Watchdog sections 11 Feb 2006 - BJD - Added Osiris machine, and S3C2400 information Document Author --------------- Ben Dooks, (c) 2004-2005,2006 Simtec Electronics