About 15 questions UBOOT, LINUX kernel compiled, the root file system

(1) run default kernel load address and address where to set?

(2) to find the kernel and root file system from what address FLASH, UBOOT where to set?

(3) UBOOT the root file system and kernel copied to RAM, where where to set the start?

(4) How UBOOT know the format and size of the kernel and root file system?

(5) the kernel boot parameters UBOOT where specified at compile time?

How to post (6) kernel know where to start to find the root file system to mount in SDRAM? How do we know the root file system size and format?

How (7) For the kernel knows UBOOT parameters passed to the kernel in the SDRAM Where?

(8) running kernel compile time where the specified address? The kernel is position-independent code do?

(9) instructions friendly arm MINI2440 wrote:
Since the present system uses a read-write file system yaffs (in embedded systems, specifically the Flash memory management
A document system), it can be easily stored dynamic data, It will not be lost after power failure. After power-running serial terminal
the following command: #cp / shanghaitan.mp3 / home / plg this time will be copied in / home under / fa a directory of the same file, and then shut down and re-open system, you can view
the / home / plg directory file still exists.

----- root file system is not already in RAM transported to the? COPY file is in RAM FLASH Lane wrote ah how will it?


(10) the kernel when the kernel boot configuration parameters can be selected. BOOTLOADER can pass parameters. These two parameters are complementary relationship, or who preferred relationship (if there is a conflict)?

(11) friendly board SUPERVIVI / UBOOT boot from NOR file can then be programmed to NAND, but can not start then program the file from NAND to NOR ---- burn files to a NOR need HJTAG or JLINK, BOOTLOADER, as there is support UBOOT Writing NOR do?



If you already have if the top (12) configure the kernel (or VIVI) with a good run MAKE MENUCONFIG specially set .config, make will automatically be transferred to .config configuration, but if there is no .config shows which default values in accordance with it?

(13) LINUX kernel and root file system image information start address and size of the NAND is, is not to UBOOT coded into the program, this is the case, for a particular version of UBOOT, LINUX kernel and root filesystem It can not be programmed anywhere in the NAND. Still, the location and size of the kernel and root file system in NAND are variable, can intelligently detect these information in order to start with a normal version of linux UBOOT?

(14) to modify the code so that UBOOT UBOOT support "JFFS2 / CRAMFS / YAFFS" -------- What does it mean? uboot is not the role of the FLASH in the root file system handling to SDRAM in it? Whether it is able to COPY what format to SDRAM soon the line yet?

(15) It is said lINUX kernel can also be loaded into memory to run local FLASH, UBOOT is which way? Compile UBOOT can choose which way to use it?

1. see "Embedded LINUX application development entirely manual" 302
2. UBOOT there are environmental variables, UBOOT after the start, the command will be executed according to bootcmd this environment variable. It was in this environment variable states: where to read kernel;
file systems where the kernel is determined, it is recommended that you press the order of a good read.
3. Start UBOOT not copy the root file system, the kernel where to copy, see bootcmd environment variables
4. UBOOT regardless of the file system, the kernel is the image that can be run directly, nothing special format
5. UBOOT see that their own chapter
6. After the kernel boot, not looking for the file system in SDRAM, but to find on FLASH, you see kernel porting, the root file system that Chapter 2
7. UBOOT see the chapter
8. See the chapter kernel, the kernel starts a small portion of the code is position independent
9. RAM with no relationship
parameter 10. the transmission priority
11, the present UBOOT forum can be directly programmed NOR
12. try to know
13. UBOOT just where the kernel, this address can be set by command, not hard-coded;
the file system to find the kernel, the address is usually hard-coded in the kernel
14. support the programming of these types of file system image file
15. the kernel can run directly on the NOR, which now UBOOT okay, UBOOT only responsible for what hardware initialization, and then if possible, the kernel is copied to the SDRAM, and then start the kernel;
if the kernel is running, then finish the hardware initialization after UBOOT directly boot the kernel on NOR