So . . .
On Fri, Dec 23, 2016 at 3:50 PM, Robert Nelson <[email protected]>
wrote:
> Okay, i have a version of u-boot with overlays enabled, ready for some
> basic testing..
>
> *************Background***************************************
>
> in u-boot we are doing:
>
> dtb= is loaded at ${fdtaddr}
>
> We read /boot/uEnv.txt for (dtb_overlay=<path/file.dtbo>)
>
> then load it, into ${rdaddr} #(no reason that specific address)
>
> Then we must run thru this routine:
>
> fdt addr ${fdtaddr}
> fdt resize;
> fdt apply ${rdaddr}
> fdt resize;
>
> Without the "fdt resize, the jump to kernel bomb's in bootz."
>
> *****************************************************************
>
> *************Actual testing...***************************************
>
> Step 1: Do you have a usb serial adapter to monitor the boot process?
>
> no = stop reading now... till you have one in hand...
> yes = please continue
>
> Step 2: Remove /uEnv.txt (i forgot to code that path in this test)
>
> rm /uEnv.txt
>
> Step 3: Update u-boot to v2017.01-rc2
>
> cd /opt/scripts/tools/developers/
> git pull
> ./update_bootloader.sh --use-beta-bootloader
>
> On reboot, it should show:
>
> U-Boot SPL 2017.01-rc2-00002-g52b3c56009 (Dec 23 2016 - 16:22:21)
> Trying to boot from MMC1
>
> U-Boot 2017.01-rc2-00002-g52b3c56009 (Dec 23 2016 - 16:22:21 -0600),
> Build: jenkins-github_Bootloader-Builder-493
>
> If not, eMMC probably messing with you..
>
> dd if=/dev/zero of=/dev/mmcblk1 bs=1M count=10
>
What ?!?
>
> Step 4: /boot/uEnv.txt
>
> remove "cape_universal=enable" we dont want any false posititves...
>
> dtb_overlay=/lib/firmware/BB-UART2-00A0.dtbo
>
> before:
> kernel:
> root@beaglebone:~# dmesg | grep serial
> [ 2.082007] 44e09000.serial: ttyS0 at MMIO 0x44e09000 (irq = 158,
> base_baud = 3000000) is a 8250
> [ 2.096583] 481a6000.serial: ttyS3 at MMIO 0x481a6000 (irq = 159,
> base_baud = 3000000) is a 8250
> [ 20.106023] systemd[1]: Created slice system-serial\x2dgetty.slice.
>
> after:
> U-Boot:
> loading /boot/dtbs/4.4.39-ti-r75/am335x-boneblack-wireless.dtb ...
> 64988 bytes read in 163 ms (388.7 KiB/s)
> debug: [dtb_overlay=/lib/firmware/BB-UART2-00A0.dtbo] ...
> loading /lib/firmware/BB-UART2-00A0.dtbo ...
> 883 bytes read in 276 ms (2.9 KiB/s)
>
> kernel:
> root@beaglebone:~# dmesg | grep serial
> [ 2.081559] 44e09000.serial: ttyS0 at MMIO 0x44e09000 (irq = 158,
> base_baud = 3000000) is a 8250
> [ 2.095942] 48024000.serial: ttyS2 at MMIO 0x48024000 (irq = 159,
> base_baud = 3000000) is a 8250
> [ 2.096807] 481a6000.serial: ttyS3 at MMIO 0x481a6000 (irq = 160,
> base_baud = 3000000) is a 8250
> [ 20.316939] systemd[1]: Created slice system-serial\x2dgetty.slice.
>
> Step 5: Profit!!! ;)
>
> *****************************************************************
>
> I know it's a little limited, but something for testing over Christmas. ;)
>
> FAQ:
>
> What does this solve? Lots of random kernel races... (looking at
> video/emmc/etc)... As U-Boot updates the final *.dtb and not the
> kernel...
>
> What about 2+ overlays? Maybe next week, for Christmas you get one.. ;)
>
> Does this replace the current method? No it just improves things..
>
> What have you tested it on? Just BB-UART2-00A0.dtbo and then i wrote
> this email up and got ready to go home...
>
> Will it read the eeprom and auto load the correct overlay? Sure,
> sometime between next week and the start of the new year... ;)
>
> Will this fix the issue with the painful out of box experience with
> LCD3/LCD4/LCD7? Correct, as long as they have an eeprom. ;)
>
> How do i actually test things?
>
> Easiest, /boot/uEnv.txt
>
> dtb=am335x-boneblack-overlay.dtb
> dtb_overlay=/lib/firmware/xyz.dtbo
>
>
Ok, so I have zero problems testing. But what I do have problems with is
understanding how to get from point A to point B
Exact steps, with no "mumbo jumbo" in between.
So first, will this work with the latest "stable" image ? If so, why would
I want to destroy the partition table of the only boot-able partition ? I
would actually want the partition table intact so I can make these changes
while reflecting those same changes.on the boot able "image" / file system.
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