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The NMDK8815 board is distributed by ST Microelectornics. Other (proprietary) code must be run to unlock the CPU before U-Boot runs. doc/README.nmdk8815 outlines the boot sequence. This is the initial port, with basic infrastructure and a working serial port. Signed-off-by: Alessandro Rubini <rubini@unipv.it> Acked-by: Andrea Gallo <andrea.gallo@stnwireless.com> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
23 lines
1.0 KiB
Plaintext
23 lines
1.0 KiB
Plaintext
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The Nomadik 8815 CPU has a "secure" boot mode where no external access
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(not even JTAG) is allowed. The "remap" bits in the evaluation board
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are configured in order to boot from the internal ROM memory (in
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secure mode).
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The boot process as defined by the manufacturer executes external code
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(loaded from NAND or OneNAND) that that disables such "security" in
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order to run u-boot and later the kernel without constraints. Such
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code is a proprietary initial boot loader, called "X-Loader" (in case
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anyone wonders, it has no relations with other loaders with the same
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name and there is no GPL code inside the ST X-Loader).
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SDRAM configuration, PLL setup and initial loading from NAND is
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implemented in the X-Loader, so U-Boot is already running in SDRAM
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when control is handed over to it.
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On www.st.com/nomadik and on www.stnwireless.com there are documents,
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summary data and white papers on Nomadik. The full datasheet for
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STn8815 is not currently available on line but under specific request
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to the local ST sales offices.
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