On Fri, Aug 21, 2020 at 05:30:54PM -0400, Peter Geis wrote: > On Fri, Aug 21, 2020 at 5:04 PM Tom Rini <trini@xxxxxxxxxxxx> wrote: > > > > On Fri, Aug 21, 2020 at 04:17:24PM -0400, Peter Geis wrote: > > > On Mon, Jul 6, 2020 at 3:48 PM Peter Geis <pgwipeout@xxxxxxxxx> wrote: > > > > > > > > On Mon, Jul 6, 2020 at 1:04 PM Stephen Warren <swarren@xxxxxxxxxxxxx> wrote: > > > > > > > > > > On 7/3/20 6:32 AM, Peter Geis wrote: > > > > > > Good Morning, > > > > > > > > > > > > I am attempting to expand on the work for chainloading U-Boot on the > > > > > > nyan-big in order to chainload U-Boot on the Ouya Tegra30 device from fastboot. > > > > > > I have so far been unsuccessful at getting any output from U-Boot > > > > > > through this method. > > > > > > > > > > I assume that fastboot executes the loaded code on the main CPU not on > > > > > the boot CPU (AVP). U-Boot SPL on Tegra30 expects to start running on > > > > > the AVP though; you would have to disable SPL to make this all work, and > > > > > perhaps fix U-Boot to work without SPL present. I'm not sure what, if > > > > > any, changes would be required to support that. > > > > > > > > > > For background, see: > > > > > https://http.download.nvidia.com/tegra-public-appnotes/index.html > > > > > > > > Apologies for the resend, I realized I didn't reply to the list. > > > > > > > > I admit I'm still extremely new to U-Boot, but this is the way I > > > > understand the boot flow. > > > > ROM does extremely low level init, then loads U-boot SPL. > > > > U-Boot SPL does basic init, ram, cpu and required peripherals, then > > > > loads U-Boot.bin. > > > > U-Boot.bin is U-Boot proper, with the full interface. > > > > > > > > By loading U-Boot.bin as the nyan instructions indicated, I'm > > > > bypassing the SPL code as if it was already complete. > > > > The issue I have is I'm not sure what modifications were done to the > > > > T124 code to allow nyan to do this. > > > > I've compared the nyan configs to the cardhu configs and I don't see > > > > anything that sticks out to me. > > > > I've also dug through the nyan git log and I don't see anything that > > > > was specifically changed to allow chainloading on T124. > > > > > > > > I also am unsure of where fastboot is loading the kernel in order to > > > > set the text base correctly. > > > > > > For anyone interested, I succeeded at chainloading u-boot on the Ouya. > > > > Nice work. > > > > > The Linux Kernel with low level debugging enabled in the decompressor > > > will print the load address. > > > > > > Jumping to kernel at:4861 ms > > > > > > C:0x80A000C0-0x8112BA40->0x8152C700-0x81C58080 > > > Uncompressing Linux... > > > > > > So by setting the u-boot text base to 0x80A00000 u-boot now executes, > > > but it would then immediately silently reboot. > > > Turns out I needed to define the console in the device-tree, which > > > isn't defined in the u-boot tegra30-cardhu.dts. > > > It would then freeze at relocation time, as it was trying to overwrite > > > the trustzone ram space. > > > #define CONFIG_PRAM 2048 solves that issue. > > > > > > I'd like to know if u-boot can read the reserved-memory device-tree > > > node and use it instead of CONFIG_PRAM? > > > > Honestly, this is what CONFIG_PRAM is for. We could possibly add > > something to get this from device-tree, but we might need to do that > > early enough that it becomes a tricky thing to do. > > Thank you, that makes sense. > > > > > > Otherwise the only issue it seems to have it is does not read the > > > nvidia proprietary partition table. > > > Is there a way to force u-boot to read the backup gpt table similar to > > > the android kernel's method? > > > > Some tangential experiments the other day and I saw that U-Boot would > > read the backup GPT if it's at the expected place. But that might be > > only after you do something like "part list mmc 0", so there might in > > turn be places that we need to be a bit more robust in our checking. > > Unfortunately running <part list mmc 0> returns "## Unknown partition > table type 0" > > This is the result of the gpt guid command: > Tegra30 (Ouya) # gpt guid mmc 0 > GUID Partition Table Header signature is wrong: 0x1000 != 0x5452415020494645 > find_valid_gpt: *** ERROR: Invalid GPT *** > find_valid_gpt: *** Using Backup GPT *** > 00000000-0000-0000-0000-000000000000 > success! > > The backup GPT is a valid GPT, and linux will pull the partition table > from it if forced to look there. > The android kernel handled this by adding "gpt gpt_sector=15073279" to > the command line. Ah, interesting. And where is that sector in relation to where the backup should be? I'm not sure off-hand how easy it would be to make backup location easy to run-time configure, but if it's lba - 2 instead of lba - 1 or something, we could add a build-time "also check.." thing, if it's a consistent offset, and probably is. Similarly, we could add something kinda ugly to allow overriding GPT_PRIMARY_PARTITION_TABLE_LBA with where that is instead. Other-otherwise, I know there's patches in progress to support "tegra partition table" for Linux and doing that for U-Boot could be handy and fix this problem as well? -- Tom
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