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| − | CM-T3530 firmware consists of two components: X-Loader and U-Boot. X-Loader is the bootstrap utility invoked by the boot ROM code of OMAP35x processor. X-Loader performs minimal hardware initialization and loads stage two bootloader, namely U-Boot. U-Boot initializes hardware modules necessary for system boot and loads the operating system.
| + | #REDIRECT [[CM-T3x: U-Boot: Firmware Overview]] |
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| − | == X-Loader ==
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| − | X-Loader should reside in the first erase block of the system NAND flash or in a file on MMC/SD card. It is loaded into OMAP35x internal SRAM immediately after system reset. The OMAP35x internal boot ROM determines what storage media to use in accordance with BOOT_SOURCE signal value (pin 65 of connector P1 on CM-T3530). SB-T35 allows easy switch between NAND and MMC/SD boot.
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| − | X-Loader is responsible for initial clock setup, DDR initialization and boot media controller initialization. After basic hardware setup X-Loader loads U-Boot bootloader into the system RAM and transfers control to the U-Boot bootloader.
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| − | == U-Boot ==
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| − | U-Boot is the stage two bootloader used on CM-T3530. It allows flexible selection of operating system boot modes, provides scripting facilities and command line interface through serial port.
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| − | U-Boot should reside in the system NAND flash starting from offset 0x80000. In addition, two blocks at offset 0x260000 are used by the U-Boot environment. In case an MMC/SD card is used as boot media, U-Boot binary should be present in card's root directory and named {{filename|u-boot.bin}}.
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| − | U-Boot allows booting operating system from the on-board NAND flash, MMC/SD card or from network.
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| − | Please consult [[U-Boot quick reference]] and [http://www.denx.de/wiki/U-Boot/Documentation U-Boot project documentation] for U-Boot features and commands description.
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| − | == Boot sources ==
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| − | CM-T3530 can boot either from on-board NAND flash or from MMC/SD card. The boot source can be selected using jumper E6 or button SW1 on SB-T35.
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| − | * To boot the system from the on-board NAND flash make sure that jumper E6 is not present.
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| − | * To boot the system from the MMC/SD card install jumper E6 before power-on or hold button SW1 during system startup.
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| − | Please refer to [[CM-T3530: Linux: Booting from MMC/SD card]] for further details.
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| − | == Default NAND flash mapping ==
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| − | {| cellpadding="3" border="1" style="border: 1px solid rgb(85, 85, 85); border-collapse: collapse;"
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| − | |+ CM-T3530 NAND flash mapping
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| − | |-
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| − | ! Offset
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| − | ! Description
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| − | ! Size (kilobytes)
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| − | |-
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| − | | 0x0
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| − | | X-Loader
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| − | | 512
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| − | |-
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| − | | 0x80000
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| − | | U-Boot
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| − | | 640
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| − | |-
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| − | | 0x12000
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| − | | Reserved
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| − | | 1280
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| − | |-
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| − | | 0x260000
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| − | | U-Boot environment
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| − | | 256
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| − | |-
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| − | | 0x2a0000
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| − | | Linux kernel
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| − | | 4096
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| − | |-
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| − | | 0x6a0000
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| − | | Linux filesystem
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| − | | remaining NAND flash space
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| − | |}
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| − | == Know issues ==
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| − | * If U-Boot environment variable {{parameter|bootdelay}} is set to 0 or an invalid value, automatic OS boot cannot be stopped.
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| − | [[Category:U-Boot|Firmware Overview]]
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| − | [[Category:CM-T3530|U-Boot: Firmware Overview]]
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