Re: imx7d enable second core

[Giorgio Dal Molin <giorgio.nicole@arcor.de>]

Hi Ahmad,

thanks for answering,

actually I've already done some tests with the 'smc' DEBUG command but I think
and the results I got are not the expected ones.

(I must admit I'm not really an expert upon this PSCI subsystem of the imx7, so
I could be making some trivial errors...)

For example, if I directly execute 'smc -c' or a 'smc -i' just after barebox
booted up I get a crash:

imx7: / smc -c
prefetch abort
pc : [<10fc388c>]    lr : [<bfe4a438>]
sp : bffefe10  ip : bffefe20  fp : 00000000
r10: 00000000  r9 : bfe4a55c  r8 : bfe5a0f0
r7 : 00000000  r6 : 00000000  r5 : 00000000  r4 : 00000000
r3 : 00000000  r2 : bfe4a55c  r1 : 00000001  r0 : 84000003
Flags: nZCv  IRQs off  FIQs off  Mode UK6_32

no stack data available

I think this is OK because the secure monitor is still not installed.

Executing first a 'smc -n' I have:

Hit any key to stop autoboot:    4
imx7: / smc -n
imx7: / smc -i
found psci version 1.0
imx7: / 

That's OK, I think.

Now I can try a 'smc -c' to enable the second core:

imx7: / smc -c
imx7: / 

at this point I would expect to see the debug line generated by the
'psci_printf("2nd CPU online, now turn off again\n");' present in the funtion
'second_entry(void)'. Instead I just don't see anything.
Is this the expected behavior of 'smc -c' ?

giorgio

> On October 15, 2019 at 1:37 PM Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
> 
> 
> On 10/15/19 1:29 PM, Giorgio Dal Molin wrote:
> > Hi,
> > 
> > can anyone please confirm that a recent barebox version (v2019.10 or v2019.09)
> > is able to boot a linux kernel so that it can enable the second cpu core ?
> 
> If you #define DEBUG in arch/arm/cpu/psci.c, a smc command is enabled that can
> be used to test ARM_PSCI_0_2_CPU_ON. This might aid you in your debug effort.
> 
> Cheers
> Ahmad
> 
> > It actually used to work in the past but now I only get one core running:
> > 
> > Loading ARM Linux zImage '/mnt/boot/kernel.img'
> > Loading devicetree from '/mnt/boot/devtree.dtb'
> > commandline: console=ttymxc0,115200n8 ip=11.0.0.4::11.0.0.2:255.0.0.0:armgdm:eth0: root=PARTUUID=abd2f9f6-88e5-4657-a5fb-aeb2cc6fde7e rootwait video=HDMI-A-1:1024x768M@60 console=tty1
> > Starting kernel in nonsecure mode
> > [    0.000000] 000: Booting Linux on physical CPU 0x0
> > [    0.000000] 000: Linux version 5.2.19-rt11-00268-g0308d71d8410-dirty (giorgio@BVblfs) (gcc version 9.2.1 20190813 (OSELAS.Toolchain 9.2.1)) #1 SMP PREEMPT RT Thu Oct 10 07:50:01 CEST 2019
> > [    0.000000] 000: CPU: ARMv7 Processor [410fc075] revision 5 (ARMv7), cr=10c5387d
> > [    0.000000] 000: CPU: div instructions available: patching division code
> > [    0.000000] 000: CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
> > [    0.000000] 000: OF: fdt: Machine model: Freescale i.MX7 SabreSD Board
> > [    0.000000] 000: Memory policy: Data cache writealloc
> > [    0.000000] 000: cma: Reserved 64 MiB at 0xac000000
> > [    0.000000] 000: percpu: Embedded 10 pages/cpu s19296 r0 d21664 u40960
> > [    0.000000] 000: Built 1 zonelists, mobility grouping on.  Total pages: 260608
> > [    0.000000] 000: Kernel command line: console=ttymxc0,115200n8 ip=11.0.0.4::11.0.0.2:255.0.0.0:armgdm:eth0: root=PARTUUID=abd2f9f6-88e5-4657-a5fb-aeb2cc6fde7e rootwait video=HDMI-A-1:1024x768M@60 console=tty1
> > [    0.000000] 000: Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes)
> > [    0.000000] 000: Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
> > [    0.000000] 000: Memory: 958252K/1048576K available (9216K kernel code, 403K rwdata, 2308K rodata, 1024K init, 719K bss, 24788K reserved, 65536K cma-reserved, 261700K highmem)
> > [    0.000000] 000: SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=1
> > [    0.000000] 000: rcu: Preemptible hierarchical RCU implementation.
> > [    0.000000] 000: rcu:        RCU priority boosting: priority 1 delay 500 ms.
> > [    0.000000] 000: rcu:        RCU_SOFTIRQ processing moved to rcuc kthreads.
> > [    0.000000] 000:     No expedited grace period (rcu_normal_after_boot).
> > [    0.000000] 000:     Tasks RCU enabled.
> > [    0.000000] 000: rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
> > [    0.000000] 000: NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
> > [    0.000000] 000: rcu:        Offload RCU callbacks from CPUs: (none).
> > [    0.000000] 000: arch_timer: cp15 timer(s) running at 8.00MHz (virt).
> > [    0.000000] 000: clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x1d854df40, max_idle_ns: 440795202120 ns
> > [    0.000001] 000: sched_clock: 56 bits at 8MHz, resolution 125ns, wraps every 2199023255500ns
> > [    0.000012] 000: Switching to timer-based delay loop, resolution 125ns
> > [    0.000433] 000: Switching to timer-based delay loop, resolution 41ns
> > [    0.000445] 000: sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
> > [    0.000456] 000: clocksource: mxc_timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns
> > [    0.001625] 000: Console: colour dummy device 80x30
> > [    0.001638] 000: printk: console [tty1] enabled
> > [    0.001673] 000: Calibrating delay loop (skipped), value calculated using timer frequency.. 48.00 BogoMIPS (lpj=240000)
> > [    0.001680] 000: pid_max: default: 32768 minimum: 301
> > [    0.001816] 000: Mount-cache hash table entries: 2048 (order: 1, 8192 bytes)
> > [    0.001833] 000: Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes)
> > [    0.002543] 000: CPU: Testing write buffer coherency: ok
> > [    0.002896] 000: CPU0: update cpu_capacity 1024
> > [    0.002908] 000: CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
> > [    0.060000] 000: Setting up static identity map for 0x80100000 - 0x8010003c
> > [    0.079971] 000: rcu: Hierarchical SRCU implementation.
> > [    0.160105] 000: smp: Bringing up secondary CPUs ...
> > [    0.280352] 000: smp: Brought up 1 node, 1 CPU
> > [    0.280362] 000: SMP: Total of 1 processors activated (48.00 BogoMIPS).
> > [    0.280370] 000: CPU: All CPU(s) started in SVC mode.
> > [    0.281280] 000: devtmpfs: initialized
> > 
> > giorgio
> > 
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> 
> 
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