PICO-PI iMX7D booted with only 1 CPU at 1.0GHz

Embedded Linux Discussions
1

hello everyone. I just followed the instruction at “https://www.digikey.com/eewiki/display/linuxonarm/PICO-PI-IMX7”, and after several attempts, it finally boot up sucessfully, with wifi and audio working :grinning:.

one remaining issue is, it only use 1 cpu core at 1.0GHz (cat /proc/cpuinfo only show up 1 cpu, and benchmark also confirm this fact), instead of two 1.2GHz CPUs on the board. could you please give me some suggestions how to fix this issue. Thanks.

kernel version: 5.1.18-armv7-lpae-x14.4
rootfs: debian-10.4-minimal-armhf-2020-05-10.tar.xz
u-boot:
U-Boot 2019.07-rc4 (Jul 23 2020 - 13:16:43 +0000)

CPU:   Freescale i.MX7D rev1.2 1000 MHz (running at 792 MHz)
CPU:   Commercial temperature grade (0C to 95C) at 46C
Model: TechNexion PICO-IMX7D Board and PI baseboard
Board: i.MX7D PICOSOM
...
Retrieving file: /boot/dtbs/5.1.18-armv7-lpae-x14.4/imx7d-pico-pi.dtb
...
Starting kernel ...

[    1.401300] spi_imx 30840000.spi: dma setup error -19, use pio
[    1.472111] CPUidle arm: CPU 0 failed to init idle CPU ops
SELinux:  Could not open policy file <= /etc/selinux/targeted/policy/policy.31:  No such file or directory
[    2.763351] mmc1: error -110 whilst initialising SDIO card
...
2

Hi @mimitech, thanks for the report! I’ll take a look at this, i thought i saw two cores when i did my initial v5.1.x work.

Any chance can you give the v5.4.x or v5.8.x branches a quick test?

git checkout origin/v5.4.x -b tmp-v5.4

git checkout origin/v5.8.x -b tmp-v5.8

Regards,

3

Hi, Robert, thanks for your information.I’m just compiling these two kernel version. but I could only test new kernels tomorrow, as the board are runing some non-stop task right now. I’ll come back with the result of new kernels, thanks again.

4

Hi @mimitech, found my board, luckly it wasn’t stuck at work:

debian@arm:~$ dmesg | grep smp
[    0.056143] smp: Bringing up secondary CPUs ...
[    0.088446] smp: Brought up 1 node, 1 CPU
debian@arm:~$ cat /proc/cpuinfo 
processor	: 0
model name	: ARMv7 Processor rev 5 (v7l)
BogoMIPS	: 60.36
Features	: half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm 
CPU implementer	: 0x41
CPU architecture: 7
CPU variant	: 0x0
CPU part	: 0xc07
CPU revision	: 5

Hardware	: Freescale i.MX7 Dual (Device Tree)
Revision	: 0000
Serial		: 0000000000000000
debian@arm:~$ uname -r
5.1.18-armv7-lpae-x14.4

Now digging into it.

Okay, small update, booting u-boot v2020.07 an 5.8.x-rc7 no dice… Looking around i found this bug report:

https://community.nxp.com/thread/460616

We need to figure out what’s missing for PSCI support…

it’s enabled in u-boot:

u-boot$ cat .config| grep PSCI
CONFIG_ARCH_SUPPORT_PSCI=y
CONFIG_ARMV7_PSCI=y
CONFIG_ARMV7_PSCI_NR_CPUS=4

Regards,

5

hi, @RobertCNelson

thanks very much for your information.

I just find out a post here [U-Boot] imx7d: CPU core issue in secure mode, as stated by this post, I just add a u-boot command “setenv bootm_boot_mode nonsec”, then the kernel boot up with two CPU cores :grinning: :smile:

looks like it’s something related to TEE implementation… anyway, it woks.

Regards

6

With the mainline 5.1.x kernel, the max cpu freq is 1.0GHz, instead of 1.2GHz when running TechNexion provided 4.1.15 kernel. not a big issue anyway.

Operating System	Linux 5.1.18-armv7-lpae-x14.4 armv7l
Processor	ARM Freescale @ 996 MHz, 1 processor, 2 threads

VS

Operating System	Ubuntu 16.04.6 LTS 4.1.15_2.0.0-00599-g93b0ae1 armv7l
Processor	ARM Freescale @ 1.20 GHz, 1 processor, 2 threads
7

hi, @RobertCNelson

some minor comments about your offical guide at “https://www.digikey.com/eewiki/display/linuxonarm/PICO-PI-IMX7”, I must skip following steps:

sudo dd if=/dev/zero of=${DISK} bs=1M count=10
sudo dd if=./u-boot/SPL of=${DISK} seek=1 bs=1k
sudo dd if=./u-boot/u-boot-dtb.img of=${DISK} seek=69 bs=1k

or else board didn’t boot, there were no u-boot prompt.

I guess if I skipped these dd commands, I were using SPL/u-boot flashed by dfu-uitls. I also used fdisk instead of sfdisk to create MMC partition, so I’m not very sure which command (‘dd’ or ‘sfdisk’) corrupted the SPL/u-boot.

Thanks very much for your complete guide and help.

Regards

8

hi, @RobertCNelson

I have tested kernel 5.4.x and 5.8.x, with same u-boot 2020.07 version and same rootfs, they all booted, but wifi is not working in both versions, broadcom driver is loaded but not working ,iwlist scan failed. so I have switched back to 5.1.x kernel.

thanks and regards