Documentation/arm/Samsung-S3C24XX/Overview.txt - kernel/msm - Gitiles

 			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, S3C2440, S3C2442 and S3C2443 devices are supported.

   Support for the S3C2400 and S3C24A0 series are 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.


 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.txt


 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.


 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, (c) 2004-2005,2006 Simtec Electronics
	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, S3C2440, S3C2442 and S3C2443 devices are supported.

	Support for the S3C2400 and S3C24A0 series are 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.


	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.txt


	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.


	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, (c) 2004-2005,2006 Simtec Electronics