Updated documentation regarding source based ramdisk (buildroot). Clo…

…ses issue RedPitaya#1.

COPYING

@@ -3,6 +3,7 @@ Red Pitaya software is released under BSD license.
 Explicitly, "Red Pitaya software", affected by this license, includes files
 in the following directories recursively:
 - Applications
+- OS/buildroot
 - OS/discovery
 - OS/filesystem
 - Bazaar/nginx/ngx_ext_modules/ngx_http_rp_module

OS/README

@@ -2,55 +2,34 @@ This is the GNU/Linux Operating system for Red Pitaya, an Open-source
 instrument based on Xilinx Zynq.
 
 
-FILESYSTEM
-
-The operating system consists of the following components:
-- BOOT.BIN: U-boot boot loader + initial FPGA image.
-- uImage: Linux kernel.
-- devicetree.dtb: Linux kernel device tree describing the Xilinx Zynq
-                  hardware configuration.
-- uramdisk.image.gz: Initial ramdisk, holding the root ext2 filesystem for
-                     the GNU/Linux OS. It is based on Busybox, but contains
-                     several other pieces of SW like:
-                     + Nginx web server
-                     + WiFi tools
-                     + SSH server
-
-
-Upon boot, the ramdisk image and the root filesystem resides in RAM.
-Although it is writable, its content is lost at next reboot or power cycle.
-This way, better OS robustness to abrupt power loss is achieved.
-
-BUILD
-
-These OS components sould have an automated build from the respective
-sources and configuration with clear versioning. Until this is established,
-these components are staged in the filesystem sub-directory.
-
-The Linux kernel uImage is build from git repository defined by LINUX_GIT build
-valiable. By defaulty local (/var/git/linux-xlnx.git) bare repository is used.
-This can be changed if remote repository is to be used.
-e.g. make clean all LINUX_GIT=git://10.0.1.150/linux-xlnx.git
+DIRECTORIES
 
-TOOLS
+u-boot          U-boot boot loader.
+linux           Linux kernel.
+buildroot       Root filesystem (ramdisk).
+discovery       IP discovery connection agent.
+filesystem      Overlay for SD card filesystem, holding user configurable
+                files.
 
-The tools sub-directory contains the tools to allow for easy manipulation of
-the ramdisk content.
-
-Usage (on any Linux system):
-
-> cd filesystem
-> ../tools/extract_image.sh uramdisk.image.gz
-> sudo mount -t ext2 -o loop ramdisk.img /mnt
+Upon boot, the ramdisk image and thus the root filesystem resides in RAM.
+Although it is writable, its content is lost at next reboot or power cycle.
+This way, better OS robustness to abrupt power loss is achieved, compared 
+to a root filesystem on an SD card partition being mounted in read-write
+mode.
 
-Edit files in /mnt, which represents the Linux root filesystem.
 
-> sudo umount /mnt
-> ../tools/create_image.sh ramdisk.img
+BUILD
 
+All the OS components, including the u-boot, FSBL, FPGA image, devicetree,
+Linux kernel and the ramdisk are built from sources using ../Makefile.
 
+The Linux kernel uImage is built from git repository defined by LINUX_GIT
+build valiable. By defaulty local (/var/git/linux-xlnx.git) bare repository
+is used. This can be changed if remote repository is to be used.
+E.g. make clean all LINUX_GIT=git://<host>/linux-xlnx.git.
 
-INSTALLATION
+The u-boot is built from git repository defined by UBOOT_GIT build valiable.
+By defaulty local (/var/git/u-boot-xlnx.git) bare repository is used.
+This can be changed if remote repository is to be used.
+E.g. make clean all UBOOT_GIT=git://<host>/u-boot-xlnx.git.
 
-Copy the contents of the filesystem sub-directory to the empty first partition 
-of the SD card. The SD partiton must be Windows FAT type (vfat - 0xb).

TODO

@@ -1,12 +1,11 @@
 TODO
 
-1. Fix bugs.
-2. Build  GNU/Linux ramdisk from sources, e.g. use buildroot, Yocto.
-3. Decrease the amount of duplicated code and move common components
-   to shared.
-4. Bring OS & ecosystem sources together as they compose one package.
-5. Comment the code extensively in Doxygen style. Provide Doxygen
-   documentation.
-6. Move FPGA images to specific applications.
-7. Simplify Test/monitor.
+* Fix bugs.
+* Decrease the amount of duplicated code and move common components
+  to shared.
+* Bring OS & ecosystem sources together as they compose one package.
+* Comment the code extensively in Doxygen style. Provide Doxygen
+  documentation.
+* Move FPGA images to specific applications.
+* Simplify Test/monitor.