| Pantelis Antoniou | d80162c | 2017-09-04 23:12:18 +0300 | [diff] [blame^] | 1 | U-Boot FDT Overlay usage (without FIT images) |
| 2 | ============================================= |
| 3 | |
| 4 | FDT overlays are now available for use even without FIT images. |
| 5 | It is not as automagic as with FIT images though and require a few |
| 6 | manual steps. |
| 7 | |
| 8 | 1. Figure out where to place both the base device tree blob and the |
| 9 | overlay. Make sure you have enough space to grow the base tree without |
| 10 | overlapping anything. |
| 11 | |
| 12 | => setenv fdtaddr 0x87f00000 |
| 13 | => setenv fdtovaddr 0x87fc0000 |
| 14 | |
| 15 | 2. Load the base blob and overlay blobs |
| 16 | |
| 17 | => load ${devtype} ${bootpart} ${fdtaddr} ${bootdir}/base.dtb |
| 18 | => load ${devtype} ${bootpart} ${fdtovaddr} ${bootdir}/overlay.dtb |
| 19 | |
| 20 | 3. Set it as the working fdt tree. |
| 21 | |
| 22 | => fdtaddr $fdtaddr |
| 23 | |
| 24 | 4. Grow it enough so it can 'fit' all the applied overlays |
| 25 | |
| 26 | => fdt resize 8192 |
| 27 | |
| 28 | 5. You are now ready to apply the overlay. |
| 29 | |
| 30 | => fdt apply $fdtovaddr |
| 31 | |
| 32 | Please note that in case of an error, both the base and overlays are going |
| 33 | to be invalidated, so keep copies to avoid reloading. |
| 34 | |
| 35 | Pantelis Antoniou |
| 36 | pantelis.antoniou@konsulko.com |
| 37 | 11/7/2017 |