Re: [Qemu-devel] [PATCH v2] hw/misc/zynq_slcr: Change CPU clock rate for Linux boots

[Peter Maydell]

On 13 September 2015 at 21:22, Peter Crosthwaite
<address@hidden> wrote:
> On Sat, Sep 12, 2015 at 2:06 PM, Guenter Roeck <address@hidden> wrote:
>> The Linux kernel only accepts 333334 Khz and 666667 Khz clock rates, and
>> may crash if the actual clock rate is too low. The clock rate used to be
>> (ps-clk-frequency * 26 / 4), which resulted in a CPU frequency of
>> 216666 Khz if ps-clk-frequency was set to 33333333 Hz. Change it to
>> (ps-clk-frequency * 20 / 2) = 333333 Khz for to make Linux happy.
>> Limit the change to Linux boots only.
>>
>> Signed-off-by: Guenter Roeck <address@hidden>
>>
>
> Reviewed-by: Peter Crosthwaite <address@hidden>
>
> Can this go via target-arm? (cc PMM).
>
> There may be more changes worth making on is_linux. I don't have the
> patch with the full list of FSBL-related SLCR changes handy and can't
> seem to find it in any modern Yocto trees. Wondering if Yocto still
> supports booting Zynq without FSBL (Nathan/Alistair may know more)?

I'd prefer us not to propagate lots of "only if Linux boot"
changes into devices. The GIC *must* have these because the
kernel can't configure it otherwise from non-secure mode.
I'm not sure that applies here.

thanks
-- PMM