28 lines
1.2 KiB
Plaintext
28 lines
1.2 KiB
Plaintext
-------------- omap4_usb_booting --------------
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omap4 processors have support for booting from the usb port. To be able to fully
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use this feature you will need to enable the following:
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OMAP4_USBBOOT
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This CONFIG_ option adds the required infrastructure.
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DRIVER_SERIAL_OMAP4_USBBOOT
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This adds console support over the same usb port used for booting.
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FS_OMAP4_USBBOOT
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This adds filesystem support over the same usb port used for booting.
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To send the bootloader to the processor, execute the utility omap4_usbboot which
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can be found in the scripts subdirectory.
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omap4_usbboot takes two parameters:
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the bootloader image
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a directory name which will be the root for the guest system
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Once omap4_usbboot is running it will wait for enumeration of the omap4 cpu on
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the host usb subsystem. Then power on or reset the cpu with the correct sys_boot
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or SAR memory configuration.
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If everything works, barebox's first stage will boot and afterwards it will load
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the second stage found at "/barebox.bin".
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Barebox's second stage will still have access to the usb filesystem, so an
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initrd and a zImage can be loaded.
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Overall this procedure frees the developer of continously be changing the SD
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card or other boot media from host to target.
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