| ========================== |
| 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, |
| S3C2412, S3C2413, S3C2416, S3C2440, S3C2442, S3C2443 and S3C2450 devices |
| are supported. |
| |
| Support for the S3C2400 and S3C24A0 series was never completed and the |
| corresponding code has been removed after a while. If someone wishes to |
| revive this effort, partial support can be retrieved from earlier Linux |
| versions. |
| |
| The S3C2416 and S3C2450 devices are very similar and S3C2450 support is |
| included under the arch/arm/mach-s3c2416 directory. Note, while core |
| support for these SoCs is in, work on some of the extra peripherals |
| and extra interrupts is still ongoing. |
| |
| |
| 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. |
| |
| |
| Layout |
| ------ |
| |
| The core support files are located in the platform code contained in |
| arch/arm/plat-s3c24xx with headers in include/asm-arm/plat-s3c24xx. |
| This directory should be kept to items shared between the platform |
| code (arch/arm/plat-s3c24xx) and the arch/arm/mach-s3c24* code. |
| |
| Each cpu has a directory with the support files for it, and the |
| machines that carry the device. For example S3C2410 is contained |
| in arch/arm/mach-s3c2410 and S3C2440 in arch/arm/mach-s3c2440 |
| |
| Register, kernel and platform data definitions are held in the |
| arch/arm/mach-s3c2410 directory./include/mach |
| |
| arch/arm/plat-s3c24xx: |
| |
| Files in here are either common to all the s3c24xx family, |
| or are common to only some of them with names to indicate this |
| status. The files that are not common to all are generally named |
| with the initial cpu they support in the series to ensure a short |
| name without any possibility of confusion with newer devices. |
| |
| As an example, initially s3c244x would cover s3c2440 and s3c2442, but |
| with the s3c2443 which does not share many of the same drivers in |
| this directory, the name becomes invalid. We stick to s3c2440-<x> |
| to indicate a driver that is s3c2440 and s3c2442 compatible. |
| |
| This does mean that to find the status of any given SoC, a number |
| of directories may need to be searched. |
| |
| |
| 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/Aiji SMDK2412 |
| |
| The S3C2412 version of the SMDK2440. |
| |
| Samsung/Aiji SMDK2413 |
| |
| The S3C2412 version of the SMDK2440. |
| |
| Samsung/Meritech SMDK2440 |
| |
| The S3C2440 compatible version of the SMDK2440, which has the |
| option of an S3C2440 or S3C2442 CPU module. |
| |
| 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 . |
| |
| AML M5900 |
| |
| American Microsystems' M5900 |
| |
| Nex Vision Nexcoder |
| Nex Vision Otom |
| |
| Two machines by Nex Vision |
| |
| |
| Adding New Machines |
| ------------------- |
| |
| The architecture 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 <ben-linux@fluff.org> 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. |
| |
| This has recently been upgraded to use the new RTC core, |
| and the module has been renamed to rtc-s3c to fit in with |
| the new rtc naming scheme. |
| |
| |
| 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 |
| code can be found from http://www.linux-mtd.infradead.org/ |
| |
| For more information see Documentation/arm/samsung-s3c24xx/nand.rst |
| |
| |
| SD/MMC |
| ------ |
| |
| The SD/MMC hardware pre S3C2443 is supported in the current |
| kernel, the driver is drivers/mmc/host/s3cmci.c and supports |
| 1 and 4 bit SD or MMC cards. |
| |
| The SDIO behaviour of this driver has not been fully tested. There is no |
| current support for hardware SDIO interrupts. |
| |
| |
| 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. |
| |
| Newer kernels carry GPIOLIB, and support is being moved towards |
| this with some of the older support in line to be removed. |
| |
| As of v2.6.34, the move towards using gpiolib support is almost |
| complete, and very little of the old calls are left. |
| |
| See Documentation/arm/samsung-s3c24xx/gpio.rst for the S3C24XX specific |
| support and Documentation/arm/samsung/gpio.rst for the core Samsung |
| implementation. |
| |
| |
| 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. |
| |
| |
| SPI |
| --- |
| |
| SPI drivers are available for both the in-built hardware |
| (although there is no DMA support yet) and a generic |
| GPIO based solution. |
| |
| |
| LEDs |
| ---- |
| |
| There is support for GPIO based LEDs via a platform driver |
| in the LED subsystem. |
| |
| |
| 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 Author |
| --------------- |
| |
| Ben Dooks, Copyright 2004-2006 Simtec Electronics |
