Re: Regression on colibri-imx7 due to commit 9c1b13b3fd27 ("cyclic: reduce get_timer_us() calls inside hlist_for_each_entry_safe()")

[Emanuele Ghidoli <ghidoliemanuele@gmail.com>]

On 7/26/26 08:41, Marek Vasut wrote:
> On 7/24/26 9:36 AM, Emanuele Ghidoli wrote:
> 
> Hello everyone,
> 
>>> Regarding the timer, how come the timer is initialized so late on MX7 ?
>> timer_init() called in initcall_run_f().>
>>> The Cortex-A7 should have its own ARM timer, that should be available right
>>> from the beginning. Is that ARM timer in use on your system, or does your
>>> system use GPT timer ?
>> iMX7 uses arch/arm/mach-imx/syscounter.c.
>>
>> udelay() is called in initcall_run_f(), before timer_init().
>> arch_cpu_init() (arch/arm/mach-imx/mx7/soc.c) -> imx_gpcv2_init -> udelay
>> (which runs schedule/cyclic).
> 
> Yikes.
> 
>> And this is interesting, udelay() before timer_init() leads to a 0 us delay,
>> so there is another bug.
>>
>> I have verified that removing this udelay(65) the board boots.
> Can we start the syscounter sooner ? Something like this:
> 
> diff --git a/arch/arm/include/asm/arch-mx6/sys_proto.h b/arch/arm/include/asm/
> arch-mx6/sys_proto.h
> index 7845fa8e569..5f6759a3306 100644
> --- a/arch/arm/include/asm/arch-mx6/sys_proto.h
> +++ b/arch/arm/include/asm/arch-mx6/sys_proto.h
> @@ -36,4 +36,6 @@ static inline void iomuxc_set_rgmii_io_voltage(int io_vol)
>      __raw_writel(io_vol, IOMUXC_SW_PAD_CTL_GRP_DDR_TYPE_RGMII);
>  }
> 
> +void syscounter_init(void);
> +
>  #endif /* __SYS_PROTO_IMX6_ */
> diff --git a/arch/arm/include/asm/arch-mx7/sys_proto.h b/arch/arm/include/asm/
> arch-mx7/sys_proto.h
> index 5da0037b2c6..765764cf1bc 100644
> --- a/arch/arm/include/asm/arch-mx7/sys_proto.h
> +++ b/arch/arm/include/asm/arch-mx7/sys_proto.h
> @@ -11,4 +11,6 @@ struct wdog_regs;
> 
>  void set_wdog_reset(struct wdog_regs *wdog);
> 
> +void syscounter_init(void);
> +
>  #endif /* __SYS_PROTO_IMX7_ */
> diff --git a/arch/arm/mach-imx/mx6/soc.c b/arch/arm/mach-imx/mx6/soc.c
> index 02df86156d4..641b5d813ea 100644
> --- a/arch/arm/mach-imx/mx6/soc.c
> +++ b/arch/arm/mach-imx/mx6/soc.c
> @@ -437,6 +437,8 @@ int arch_cpu_init(void)
>           */
>          if (mxc_get_clock(MXC_ARM_CLK) == 396000000)
>              set_ahb_rate(132000000);
> +    } else {
> +        syscounter_init();
>      }
> 
>      if (is_mx6ul()) {
> diff --git a/arch/arm/mach-imx/mx7/soc.c b/arch/arm/mach-imx/mx7/soc.c
> index e504c1fd52a..82d851b7817 100644
> --- a/arch/arm/mach-imx/mx7/soc.c
> +++ b/arch/arm/mach-imx/mx7/soc.c
> @@ -331,6 +331,8 @@ int arch_cpu_init(void)
> 
>      init_snvs();
> 
> +    syscounter_init();
> +
>      imx_gpcv2_init();
> 
>      enable_ca7_smp();
> diff --git a/arch/arm/mach-imx/syscounter.c b/arch/arm/mach-imx/syscounter.c
> index 96fe2c7c17b..7b902540737 100644
> --- a/arch/arm/mach-imx/syscounter.c
> +++ b/arch/arm/mach-imx/syscounter.c
> @@ -60,7 +60,7 @@ static inline unsigned long long us_to_tick(unsigned long
> long usec)
>  }
> 
>  #if !CONFIG_IS_ENABLED(SKIP_LOWLEVEL_INIT) || IS_ENABLED(CONFIG_XPL_BUILD)
> -int timer_init(void)
> +void syscounter_init(void)
>  {
>      struct sctr_regs *sctr = (struct sctr_regs *)SCTR_BASE_ADDR;
>      unsigned long val, freq;
> @@ -80,6 +80,12 @@ int timer_init(void)
>      gd->arch.tbu = 0;
> 
>      gd->arch.timer_rate_hz = freq;
> +
> +    return 0;
> +}
> +
> +int timer_init(void)
> +{
>      return 0;
>  }
>  #endif

Hello Marek,
thanks for the suggestion.

It works, build and tested on Colibri iMX7.

But imx6 is obviously broken:
/home/emanuele/tdx/u-boot-build/u-boot/arch/arm/mach-imx/mx6/soc.c:441:
undefined reference to `syscounter_init'

Emanuele