Re: imx7d enable second core

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello Giorgio,

On 10/15/19 2:11 PM, Giorgio Dal Molin wrote:
> 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.

Ye, that's expected.

> 
> 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' ?

If ARM_PSCI_DEBUG=y, you should see something, yes.
You could git-bisect and see when it broke.


> 
> 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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>>>
>>
>>
>> -- 
>> Pengutronix e.K.                           |                             |
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> 


-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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