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 > > > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
