Hi Ahmad, Thank you for all this, there is a solid lot of info for me to go through. I really appreciate it. I'll look at the optee /tf-a situation and start there i think. Cheers Marc On Wednesday, 31 May 2023 3:50:50 PM AEST you wrote: > Hello Marc, > > On 27.05.23 07:35, marc@xxxxxxxxxxxxxxx wrote: > > Hi, > > > > Thanks for responses, some more info: > > - imx8mp based system, 1Gb LPDDR, uses same PMIC as other boards (PCA9450) > > - barebox master > > - u-boot is NXP fork > > - kernel is NXP fork, 5.15.31 > > Keep in mind that, as far as I am aware, most testing, if not all, > of the barebox i.MX8MP support was against the mainline kernel. Certainly > all projects at our side don't use NXP's fork. > > >>> I'm trying to get barebox going for a new imx8mp based board. I can > >>> successfully power on and get to a barebox prompt etc and fiddle with > >>> gpios, files on sd, memtest etc, but when booting to kernel it will > >>> hang. > >>> Note though that the board boots ok with u-boot (using exact same kernel > >>> image). > >> > >> Do you have an example crash dump? Does the kernel crash reproducibly or > >> randomly? > > > > It always hangs at the same point in the kernel boot sequence (see > > "startup- log-barebox.txt"). You can also see "startup-log-u-boot.txt" > > for the output of a complete boot. > > My go-to for hanging boot is > > no_console_suspend pm_debug_messages pd_ignore_unused clk_ignore_unused > > Maybe add maxcpus=1 and see if you get some useful indication what happens > just before hang? > > > If i change some kernel config options the boot progresses further, and > > when CONFIG_ARM_IMX_CPUFREQ_DT=n and CONFIG_IMX_SDMA=n then it will get > > to systemd starting. > > Maybe one of these drivers calls in TF-A? Do you use same TF-A/ATF in both > configurations? > > >>> I'm trying to figure out what is different between booting via uboot and > >>> barebox, I'm new to imx8 so have been going down a few rabbit holes... > > FWIW, here's a FOSDEM talk on how barebox boots the i.MX8M: > https://archive.fosdem.org/2021/schedule/event/from_reset_vector_to_kernel/ > > >>> Disabling various drivers (eg imx-cpufreq-dt) in the kernel will get > >>> past > >>> the hang, but result in a crash later on in the boot sequence. Disabling > >>> that may get further but will result in a crash somewhere else. > >>> My instinct is that its something to do with sdma, but a lot of this is > >>> still a black box to me. > >> > >> SDMA is only used in few devices like UART, I2C, SPI and sound. Apart > >> from > >> sound all devices should work without SDMA, so you could disable the > >> driver. > > > > I was getting (after disabling some things in kernel) crash traces in > > sdma_transfer_init etc, which is what made me suspect it. (see > > startup-log- > > barebox-after-kernel-change1.txt) > > Disabling the driver does indeed avoid this crash. > > Hmm, strange. > > >> PMIC comes to my mind. Does it need some configuration? > > > > The PMIC has the same register/value writes as in the u-boot version. > > Are you sure there are no writes in main U-Boot apart from what SPL sets up? > >> Is the amount of memory detected correctly by barebox? > > > > Barebox detects 1Gb, correct > > > > I did a compare of the startup logs (The cuts are to remove the > > timestamps) > > ```kompare <(diff <(cut -c 15- startup-log-u-boot.txt) <(cut -c 15- > > startup- log-barebox.txt))``` > > > > I noticed some differences in the 'reserved mem' at the start and the > > 'NUMA' early memory node ranges. > > > > When booting from u-boot I get: > > [ 0.000000] Reserved memory: created CMA memory pool at > > > > 0x0000000060000000, size 512 MiB > > > > [ 0.000000] OF: reserved mem: initialized node linux,cma, > > compatible id > > > > shared-dma-pool > > > > But when booting from barebox: > > [ 0.000000] OF: reserved mem: failed to allocate memory for node > > > > 'linux,cma' > > > > [ 0.000000] Reserved memory: created DMA memory pool at > > > > 0x0000000055400000, size 1 MiB > > > > > > For the early node ranges: > > from u-boot: > > > > [ 0.000000] NUMA: NODE_DATA [mem 0x5fdba800-0x5fdbcfff] > > [ 0.000000] Zone ranges: > > [ 0.000000] DMA [mem 0x0000000040000000-0x000000007fffffff] > > [ 0.000000] DMA32 empty > > [ 0.000000] Normal empty > > [ 0.000000] Movable zone start for each node > > [ 0.000000] Early memory node ranges > > [ 0.000000] node 0: [mem 0x0000000040000000-0x0000000054ffffff] > > [ 0.000000] node 0: [mem 0x0000000055000000-0x000000005500ffff] > > [ 0.000000] node 0: [mem 0x0000000055010000-0x00000000550fefff] > > [ 0.000000] node 0: [mem 0x00000000550ff000-0x00000000550fffff] > > [ 0.000000] node 0: [mem 0x0000000055100000-0x00000000553fffff] > > [ 0.000000] node 0: [mem 0x0000000055400000-0x00000000554fffff] > > [ 0.000000] node 0: [mem 0x0000000055500000-0x0000000055ffffff] > > [ 0.000000] node 0: [mem 0x0000000058000000-0x000000007fffffff] > > > > > > and from barebox: > > > > [ 0.000000] NUMA: NODE_DATA [mem 0x7fdaa800-0x7fdacfff] > > [ 0.000000] Zone ranges: > > [ 0.000000] DMA [mem 0x0000000040000000-0x000000007fffffff] > > [ 0.000000] DMA32 empty > > [ 0.000000] Normal empty > > [ 0.000000] Movable zone start for each node > > [ 0.000000] Early memory node ranges > > [ 0.000000] node 0: [mem 0x0000000040000000-0x0000000054ffffff] > > [ 0.000000] node 0: [mem 0x0000000055000000-0x000000005500ffff] > > [ 0.000000] node 0: [mem 0x0000000055010000-0x00000000550fefff] > > [ 0.000000] node 0: [mem 0x00000000550ff000-0x00000000550fffff] > > [ 0.000000] node 0: [mem 0x0000000055100000-0x00000000553fffff] > > [ 0.000000] node 0: [mem 0x0000000055400000-0x00000000554fffff] > > [ 0.000000] node 0: [mem 0x0000000055500000-0x000000007fffffff] > > > > Notably there is an range in the u-boot ranges which creates a gap from > > 0x56000000 to 0x57ffffff (32Mb). > > That's probably OP-TEE. That would be in line with startup-log-u-boot > saying: > > [ 1.636240] optee: revision 3.19 (00919403) > > Whether that's a problem depends on where OP-TEE comes from. On i.MX8MQ, > OP-TEE was built into TF-A. On i.MX8MM, it was usually outside. If it's > built into TF-A in your i.MX8MP setup, this would explain your problems. > > > I'm wondering how this difference comes about when both bootloaders are > > booting the same devicetree and kernel image? > > The devicetrees are not the same, because of bootloader fixups: > > - U-Boot inserts OP-TEE nodes for you. barebox can too, but you don't have > that configured (not sure if you need it) > > - NXP U-Boot messes with power domains, e.g. disable specific VPU nodes > _by name_ for stripped down versions of i.MX8MP. barebox also does > disabling, but on the upstream device tree nodes. > > If you want an accurate comparison of the device trees, look in > /proc/devicetree and compare. dtc can make a dts out of the directory. If > it's too flaky with barebox, add some -v to boot/bootm (I think -vv should > suffice) and barebox will print the fixed up device tree to console before > bootup. > > > What seems likely is that OP-TEE is built into the TF-A and you fail > to account for that. If so, try building TF-A yourself without OP-TEE and > see if it's better. The barebox docs for i.MX8MP-EVK have instructions. > > If it is better and you want OP-TEE, have OP-TEE external to TF-A. > This is better anyway, because TF-A+OP-TEE+barebox PBL may get too big in > SRAM in future. > > Let me know how it goes. > > Cheers, > Ahmad > > > Cheers > > Marc
