38 lines
1 KiB
Text
38 lines
1 KiB
Text
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U-Boot FDT Overlay usage (without FIT images)
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=============================================
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FDT overlays are now available for use even without FIT images.
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It is not as automagic as with FIT images though and require a few
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manual steps.
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1. Figure out where to place both the base device tree blob and the
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overlay. Make sure you have enough space to grow the base tree without
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overlapping anything.
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=> setenv fdtaddr 0x87f00000
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=> setenv fdtovaddr 0x87fc0000
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2. Load the base blob and overlay blobs
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=> load ${devtype} ${bootpart} ${fdtaddr} ${bootdir}/base.dtb
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=> load ${devtype} ${bootpart} ${fdtovaddr} ${bootdir}/overlay.dtb
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3. Set it as the working fdt tree.
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=> fdtaddr $fdtaddr
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4. Grow it enough so it can 'fit' all the applied overlays
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=> fdt resize 8192
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5. You are now ready to apply the overlay.
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=> fdt apply $fdtovaddr
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Please note that in case of an error, both the base and overlays are going
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to be invalidated, so keep copies to avoid reloading.
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Pantelis Antoniou
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pantelis.antoniou@konsulko.com
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11/7/2017
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