Re: [Xen-devel] [PATCH v1 3/3] xen/arm: Introduce support for Renesas R-Car Gen2 platform

[Iurii Konovalenko <iurii.konovalenko@xxxxxxxxxxxxxxx>]

On Fri, Jan 16, 2015 at 6:31 PM, Julien Grall <julien.grall@xxxxxxxxxx> wrote:
>
> On 16/01/15 16:17, Iurii Konovalenko wrote:
> > I tried to add instruction: asm volatile("mcr p15, 0, %0, c14, c0, 0" :
> > : "r" (freq));
> > Also I tried to write it via Xen API: WRITE_SYSREG32(freq, CNTFRQ_EL0);
> >
> > But unfortunately Xen fails on both this instructions with "Undefined
> > instruction" exception.
> > You can see log in attachment.
> > Could you please suggest reason, why it happens?
>
> CNTFRQ can only be written in Secure PL1 mode.
>
> I have the feeling CNTFRQ is not update automatically when Xen is
> writing in CNTFID0. So the frequency may mismatch.
>
> Assuming this, I'm wondering if we hit the second part of the if
> sentence [1] and therefore this code useful?
>

Now I understand it.
So I will set up frequency and enable timer in u-boot.
As there is no way to change frequency in Hypervisor mode, I will
remove from board file mode checking and frequency related staff.
So time init function is like:

static int __init shmobile_init_time(void)
{
    void __iomem *tmu;

    /* Remap "armgcnt address map" space */
    tmu = ioremap_nocache(SHMOBILE_ARCH_TIMER_BASE, PAGE_SIZE);
    if ( !tmu )
    {
        dprintk(XENLOG_ERR, "Unable to map TMU\n");
        return -ENOMEM;
    }
    /* Enable the timer if it is not running */
    if ( (readl_relaxed(tmu + SHMOBILE_ARCH_TIMER_CNTCR) & 1) == 0 )
        writel_relaxed(1, tmu + SHMOBILE_ARCH_TIMER_CNTCR);

    iounmap(tmu);

    return 0;
}

Am I right?

> BWT I see in the log:
>
> (XEN) /psci method must be smc, but is: "hvc"
>
> Does it mean your platform support PSCI? Or did you add the PSCI node
> for DOM0?

I added PSCI node to dom0 Device Tree:
    psci {
        compatible = "arm,psci";
        method = "hvc";
        cpu_on = <2>;
    };

>
> Regards,
>
> [1] readl_relaxed(tmu + SHMOBILE_ARCH_TIMER_CNTFID0) != freq
>
> --
> Julien Grall

Best regards.

Iurii Konovalenko | Senior Software Engineer
GlobalLogic
P +3.8044.492.9695 M +38.099.932.2909
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