Summary
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=======
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The README is for the boot procedure on the ipam390 board
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In the context of U-Boot, the board is booted in three stages. The initial
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bootloader which executes upon reset is the ROM Boot Loader (RBL) and sits
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in the internal ROM. The RBL initializes the internal memory and then
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depending on the exact board and pin configurations will initialize another
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controller (such as NAND) to continue the boot process by loading
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the secondary program loader (SPL). The SPL will initialize the system
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further (some clocks, SDRAM). As on this board is used the falcon boot
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mode, now 2 ways are possible depending on the GPIO 7_14 input pin,
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connected with the "soft reset switch"
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If this pin is logical 1 (high level):
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spl code starts the kernel image without delay
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If this pin is logical 0 (low level):
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spl code starts the u-boot image
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AIS is an image format defined by TI for the images that are to be loaded
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to memory by the RBL. The image is divided into a series of sections and
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the image's entry point is specified. Each section comes with meta data
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like the target address the section is to be copied to and the size of the
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section, which is used by the RBL to load the image. At the end of the
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image the RBL jumps to the image entry point. The AIS format allows for
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other things such as programming the clocks and SDRAM if the header is
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programmed for it. We do not take advantage of this and instead use SPL as
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it allows for additional flexibility (run-time detect of board revision,
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loading the next image from a different media, etc).
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Compilation
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===========
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run "tools/buildman/buildman -k ipam390" in the u-boot source tree.
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Once this build completes you will have a ../current/ipam390/u-boot.ais file
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that needs to be written to the nand flash.
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Flashing the images to NAND
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==========================
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The AIS image can be written to NAND flash using the following commands.
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Assuming that the network is configured and enabled and the u-boot.ais file
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is tftp'able.
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U-Boot > print upd_uboot
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upd_uboot=tftp c0000000 ${u-boot};nand erase.part u-boot;nand write c0000000 20000 ${filesize}
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U-Boot >
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U-Boot > run upd_uboot
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Using DaVinci-EMAC device
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TFTP from server 192.168.1.1; our IP address is 192.168.20.71
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Filename '/tftpboot/ipam390/u-boot.ais'.
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Load address: 0xc0000000
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Loading: ##################################
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1.5 MiB/s
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done
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Bytes transferred = 493716 (78894 hex)
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NAND erase.part: device 0 offset 0x20000, size 0x160000
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Erasing at 0x160000 -- 100% complete.
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OK
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NAND write: device 0 offset 0x20000, size 0x78894
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493716 bytes written: OK
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U-Boot >
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Recovery
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========
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In the case of a "bricked" board, you need to use the TI tools found
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here[1] to create an uboot-uart-ais.bin file
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- cd to the u-boot source tree
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- compile the u-boot for the ipam390 board:
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$ tools/buildman/buildman -k ipam390
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-> Now we shall have u-boot.bin
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- Create u-boot-uart-ais.bin
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$ mono HexAIS_OMAP-L138.exe -entrypoint 0xC1080000 -ini ipam390-ais-uart.cfg \
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-o ../current/ipam390/uboot-uart-ais.bin ./u-boot.bin@0xC1080000;
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Note: The ipam390-ais-uart.cfg is found in the board directory
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for the ipam390 board, u-boot:/board/Barix/ipam390/ipam390-ais-uart.cfg
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- We can now run bootloader on IPAM390 via UART using the command below:
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$ mono ./slh_OMAP-L138.exe -waitForDevice -v -p /dev/tty.UC-232AC uboot-uart-ais.bin
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NOTE: Do not cancel the command execution! The command takes 20+ seconds
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to upload u-boot over serial and run it!
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Outcome:
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Waiting for the OMAP-L138...
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(AIS Parse): Read magic word 0x41504954.
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(AIS Parse): Waiting for BOOTME... (power on or reset target now)
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(AIS Parse): BOOTME received!
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(AIS Parse): Performing Start-Word Sync...
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(AIS Parse): Performing Ping Opcode Sync...
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(AIS Parse): Processing command 0: 0x5853590D.
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(AIS Parse): Performing Opcode Sync...
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(AIS Parse): Executing function...
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(AIS Parse): Processing command 1: 0x5853590D.
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(AIS Parse): Performing Opcode Sync...
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(AIS Parse): Executing function...
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(AIS Parse): Processing command 2: 0x5853590D.
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(AIS Parse): Performing Opcode Sync...
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(AIS Parse): Executing function...
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(AIS Parse): Processing command 3: 0x5853590D.
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(AIS Parse): Performing Opcode Sync...
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(AIS Parse): Executing function...
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(AIS Parse): Processing command 4: 0x5853590D.
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(AIS Parse): Performing Opcode Sync...
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(AIS Parse): Executing function...
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(AIS Parse): Processing command 5: 0x58535901.
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(AIS Parse): Performing Opcode Sync...
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(AIS Parse): Loading section...
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(AIS Parse): Loaded 326516-Byte section to address 0xC1080000.
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(AIS Parse): Processing command 6: 0x58535906.
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(AIS Parse): Performing Opcode Sync...
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(AIS Parse): Performing jump and close...
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(AIS Parse): AIS complete. Jump to address 0xC1080000.
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(AIS Parse): Waiting for DONE...
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(AIS Parse): Boot completed successfully.
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Operation completed successfully.
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Falcon Bootmode (boot linux without booting U-Boot)
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===================================================
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The Falcon Mode extends this way allowing to start the Linux kernel directly
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from SPL. A new command is added to U-Boot to prepare the parameters that SPL
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must pass to the kernel, using ATAGS or Device Tree.
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In normal mode, these parameters are generated each time before
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loading the kernel, passing to Linux the address in memory where
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the parameters can be read.
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With Falcon Mode, this snapshot can be saved into persistent storage and SPL is
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informed to load it before running the kernel.
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To boot the kernel, these steps under a Falcon-aware U-Boot are required:
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1. Boot the board into U-Boot.
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Use the "spl export" command to generate the kernel parameters area or the DT.
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U-Boot runs as when it boots the kernel, but stops before passing the control
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to the kernel.
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Here the command sequence for the ipam390 board:
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- load the linux kernel image into ram:
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U-Boot > nand read c0100000 2 200000 400000
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NAND read: device 0 offset 0x200000, size 0x400000
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4194304 bytes read: OK
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- generate the bootparms image:
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U-Boot > spl export atags c0100000
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## Booting kernel from Legacy Image at c0100000 ...
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Image Name: Linux-3.5.1
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Image Type: ARM Linux Kernel Image (uncompressed)
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Data Size: 2504280 Bytes = 2.4 MiB
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Load Address: c0008000
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Entry Point: c0008000
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Verifying Checksum ... OK
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Loading Kernel Image ... OK
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subcommand not supported
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subcommand not supported
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Argument image is now in RAM at: 0xc0000100
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- copy the bootparms image into nand:
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U-Boot > mtdparts
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device nand0 <davinci_nand.0>, # parts = 6
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#: name size offset mask_flags
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0: u-boot-env 0x00020000 0x00000000 0
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1: u-boot 0x00160000 0x00020000 0
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2: bootparms 0x00020000 0x00180000 0
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3: factory-info 0x00060000 0x001a0000 0
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4: kernel 0x00400000 0x00200000 0
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5: rootfs 0x07a00000 0x00600000 0
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active partition: nand0,0 - (u-boot-env) 0x00020000 @ 0x00000000
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defaults:
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mtdids : nand0=davinci_nand.0
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mtdparts: mtdparts=davinci_nand.0:128k(u-boot-env),1408k(u-boot),128k(bootparms),384k(factory-info),4M(kernel),-(rootfs)
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U-Boot > nand erase.part bootparms
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NAND erase.part: device 0 offset 0x180000, size 0x20000
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Erasing at 0x180000 -- 100% complete.
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OK
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U-Boot > nand write c0000100 180000 20000
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NAND write: device 0 offset 0x180000, size 0x20000
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131072 bytes written: OK
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U-Boot >
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You can use also the predefined U-Boot Environment variable "setbootparms",
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which will do all the above steps in one command:
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U-Boot > print setbootparms
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setbootparms=nand read c0100000 200000 400000;spl export atags c0100000;nand erase.part bootparms;nand write c0000100 180000 20000
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U-Boot > run setbootparms
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NAND read: device 0 offset 0x200000, size 0x400000
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4194304 bytes read: OK
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## Booting kernel from Legacy Image at c0100000 ...
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Image Name: Linux-3.5.1
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Image Type: ARM Linux Kernel Image (uncompressed)
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Data Size: 2504280 Bytes = 2.4 MiB
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Load Address: c0008000
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Entry Point: c0008000
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Verifying Checksum ... OK
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Loading Kernel Image ... OK
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subcommand not supported
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subcommand not supported
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Argument image is now in RAM at: 0xc0000100
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NAND erase.part: device 0 offset 0x180000, size 0x20000
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Erasing at 0x180000 -- 100% complete.
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OK
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NAND write: device 0 offset 0x180000, size 0x20000
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131072 bytes written: OK
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U-Boot >
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Links
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=====
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[1]
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http://sourceforge.net/projects/dvflashutils/files/OMAP-L138/
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