patch-2.4.10 linux/Documentation/arm/SA1100/Assabet

• Lines: 296
• Date: Fri Sep 7 09:28:38 2001
• Orig file: v2.4.9/linux/Documentation/arm/SA1100/Assabet
• Orig date: Fri May 12 11:21:20 2000

diff -u --recursive --new-file v2.4.9/linux/Documentation/arm/SA1100/Assabet linux/Documentation/arm/SA1100/Assabet
@@ -9,38 +9,268 @@
 http://www.cs.cmu.edu/~wearable/software/assabet.html
 
 
-To build the kernel:
+Building the kernel
+-------------------
+
+To build the kernel with current defaults:
 
 	make assabet_config
-	make config
-	[accept all defaults]
+	make oldconfig
 	make dep
 	make zImage
 
-Typically, you'll need angelboot to load the kernel.
-The following angelboot.opt file should be used:
+The resulting kernel image should be available in linux/arch/arm/boot/zImage.
+
+
+Installing a bootloader
+-----------------------
+
+A couple of bootloaders able to boot Linux on Assabet are available:
+
+BLOB (http://www.lart.tudelft.nl/lartware/blob/)
+
+   BLOB is a bootloader used within the LART project.  Some contributed
+   patches were merged into BLOB to add support for Assabet.
+
+Compaq's Bootldr + John Dorsey's patch for Assabet support
+(http://www.handhelds.org/Compaq/bootldr.html)
+(http://www.wearablegroup.org/software/bootldr/)
+
+   Bootldr is the bootloader developed by Compaq for the iPAQ Pocket PC.
+   John Dorsey has produced add-on patches to add support for Assabet and
+   the JFFS filesystem.
+
+RedBoot (http://sources.redhat.com/redboot/)
+
+   RedBoot is a bootloader developed by Red Hat based on the eCos RTOS
+   hardware abstraction layer.  It supports Assabet amongst many other
+   hardware platforms.
+
+RedBoot is currently the recommended choice since it's the only one to have
+networking support, and is the most actively maintained.
+
+Brief examples on how to boot Linux with RedBoot are shown below.  But first
+you need to have RedBoot installed in your flash memory.  A known to work
+precompiled RedBoot binary is available from the following location:
+
+ftp://ftp.netwinder.org/users/n/nico/
+ftp://ftp.arm.linux.org.uk/pub/linux/arm/people/nico/
+ftp://ftp.handhelds.org/pub/linux/arm/sa-1100-patches/
+
+Look for redboot-assabet*.tgz.  Some installation infos are provided in
+redboot-assabet*.txt.
+
+
+Initial RedBoot configuration
+-----------------------------
+
+The commands used here are explained in The RedBoot User's Guide available
+on-line at http://sources.redhat.com/ecos/docs-latest/redboot/redboot.html.
+Please refer to it for explanations.
+
+If you have a CF network card (my Assabet kit contained a CF+ LP-E from
+Socket Communications Inc.), you should strongly consider using it for TFTP
+file transfers.  You must insert it before RedBoot runs since it can't detect
+it dynamically.
+
+To initialize the flash directory:
+
+	fis init -f
+
+To initialize the non-volatile settings, like whether you want to use BOOTP or
+a static IP address, etc, use this command:
+
+	fconfig -i
+
+
+Writing a kernel image into flash
+---------------------------------
+
+First, the kernel image must be loaded into RAM.  If you have the zImage file
+available on a TFTP server:
+
+	load zImage -r -b 0x100000
+
+If you rather want to use Y-Modem upload over the serial port:
+
+	load -m ymodem -r -b 0x100000
+
+To write it to flash:
+
+	fis create "Linux kernel" -b 0x100000 -l 0xc0000
+
+
+Booting the kernel
+------------------
+
+The kernel still requires a filesystem to boot.  A ramdisk image can be loaded
+as follows:
+
+	load ramdisk_image.gz -r -b 0x800000
+
+Again, Y-Modem upload can be used instead of TFTP by replacing the file name
+by '-y ymodem'.
+
+Now the kernel can be retrieved from flash like this:
+
+	fis load "Linux kernel"
+
+or loaded as described previously.  To boot the kernel:
+
+	exec -b 0x100000 -l 0xc0000
+
+The ramdisk image could be stored into flash as well, but there are better
+solutions for on-flash filesystems as mentioned below.
+
+
+Using JFFS2
+-----------
+
+Using JFFS2 (the Second Journaling Flash File System) is probably the most
+convenient way to store a writable filesystem into flash.  JFFS2 is used in
+conjunction with the MTD layer which is responsible for low-level flash
+management.  More information on the Linux MTD can be found on-line at:
+http://www.linux-mtd.infradead.org/.  A JFFS howto with some infos about
+creating JFFS/JFFS2 images is available from the same site.
+
+For instance, a sample JFFS2 image can be retrieved from the same FTP sites
+mentioned below for the precompiled RedBoot image.
+
+To load this file:
+
+	load sample_img.jffs2 -r -b 0x100000
+
+The result should look like:
+
+RedBoot> load sample_img.jffs2 -r -b 0x100000
+Raw file loaded 0x00100000-0x00377424
+
+Now we must know the size of the unallocated flash:
+
+	fis free
+
+Result:
+
+RedBoot> fis free
+  0x500E0000 .. 0x503C0000
+
+The values above may be different depending on the size of the filesystem and
+the type of flash.  See their usage below as an example and take care of
+substituting yours appropriately.
+
+We must determine some values:
+
+size of unallocated flash:	0x503c0000 - 0x500e0000 = 0x2e0000
+size of the filesystem image:	0x00377424 - 0x00100000 = 0x277424
+
+We want to fit the filesystem image of course, but we also want to give it all
+the remaining flash space as well.  To write it:
+
+	fis unlock -f 0x500E0000 -l 0x2e0000
+	fis erase -f 0x500E0000 -l 0x2e0000
+	fis write -b 0x100000 -l 0x277424 -f 0x500E0000
+	fis create "JFFS2" -n -f 0x500E0000 -l 0x2e0000
+
+Now the filesystem is associated to a MTD "partition" once Linux has discovered
+what they are in the boot process.  From Redboot, the 'fis list' command
+displays them:
+
+RedBoot> fis list
+Name              FLASH addr  Mem addr    Length      Entry point
+RedBoot           0x50000000  0x50000000  0x00020000  0x00000000
+RedBoot config    0x503C0000  0x503C0000  0x00020000  0x00000000
+FIS directory     0x503E0000  0x503E0000  0x00020000  0x00000000
+Linux kernel      0x50020000  0x00100000  0x000C0000  0x00000000
+JFFS2             0x500E0000  0x500E0000  0x002E0000  0x00000000
+
+However Linux should display something like:
+
+SA1100 flash: probing 32-bit flash bus
+SA1100 flash: Found 2 x16 devices at 0x0 in 32-bit mode
+Using RedBoot partition definition
+Creating 5 MTD partitions on "SA1100 flash":
+0x00000000-0x00020000 : "RedBoot"
+0x00020000-0x000e0000 : "Linux kernel"
+0x000e0000-0x003c0000 : "JFFS2"
+0x003c0000-0x003e0000 : "RedBoot config"
+0x003e0000-0x00400000 : "FIS directory"
+
+What's important here is the position of the partition we are interested in,
+which is the third one.  Within Linux, this correspond to /dev/mtdblock2.
+Therefore to boot Linux with the kernel and its root filesystem in flash, we
+need this RedBoot command:
+
+	fis load "Linux kernel"
+	exec -b 0x100000 -l 0xc0000 -c "root=/dev/mtdblock2"
+
+Of course other filesystems than JFFS might be used, like cramfs for example.
+You might want to boot with a root filesystem over NFS, etc.  It is also
+possible, and sometimes more convenient, to flash a filesystem directly from
+within Linux while booted from a ramdisk or NFS.  The Linux MTD repository has
+many tools to deal with flash memory as well, to erase it for example.  JFFS2
+can then be mounted directly on a freshly erased partition and files can be
+copied over directly.  Etc...
+
+
+RedBoot scripting
+-----------------
+
+All the commands above aren't so useful if they have to be typed in every
+time the Assabet is rebooted.  Therefore it's possible to automatize the boot
+process using RedBoot's scripting capability.
+
+For example, I use this to boot Linux with both the kernel and the ramdisk
+images retrieved from a TFTP server on the network:
+
+RedBoot> fconfig
+Run script at boot: false true
+Boot script:
+Enter script, terminate with empty line
+>> load zImage -r -b 0x100000
+>> load ramdisk_ks.gz -r -b 0x800000
+>> exec -b 0x100000 -l 0xc0000
+>>
+Boot script timeout (1000ms resolution): 3
+Use BOOTP for network configuration: true
+GDB connection port: 9000
+Network debug at boot time: false
+Update RedBoot non-volatile configuration - are you sure (y/n)? y
+
+Then, rebooting the Assabet is just a matter of waiting for the login prompt.
+
+
+
+Nicolas Pitre
+nico@cam.org
+June 12, 2001
+
+
+Status of peripherals in -rmk tree
+----------------------------------
+
+Assabet:
+ Serial ports:
+  Radio:	TX, RX, CTS, DSR, DCD, RI
+  COM:		TX, RX, CTS, DSR, DCD, RTS, DTR, PM
+  I2C:		TX, RX
+  L3:		No
+
+ Video:
+  LCD:		PM
+  Video out:	Not fully
+  Touchscreen:	No
+
+ Audio:
+  Codec:	No
+  POTS:		No
+
+ Other:
+  PCMCIA:	Yes
+  USB:		No
 
------ begin angelboot.opt -----
-base 0xc0008000
-entry 0xc0008000
-r0 0x00000000
-r1 0x00000019
-device /dev/ttyS1
-options "9600 8N1"
-baud 115200
-otherfile ramdisk_img.gz
-otherbase 0xc0800000
-exec minicom
------ end angelboot.opt -----
-
-Then load the kernel and ramdisk with:
-
-	angelboot -f angelboot.opt zImage
-
-Here it is assumed that your Assabet is connected to ttyS1 and that
-minicom is preconfigured with /dev/ttyS1, 9600 baud, 8N1, no flow control
-by default.
+Neponset:
+ Serial ports:
+  COM1,2:	TX, RX, CTS, DSR, DCD, RTS, DTR
 
-This is work in progress...
+More stuff can be found in the -np (Nicolas Pitre's) tree.
 
-Please send any patches to nico@cam.org.