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Date: Sun, 13 Sep 2015 14:51:43 -0700
From: Guenter Roeck <linux@roeck-us.net>
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Subject: Re: [Qemu-devel] [PATCH v2] hw/misc/zynq_slcr: Change CPU clock
 rate for Linux boots
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To: Peter Maydell <peter.maydell@linaro.org>, Peter Crosthwaite <crosthwaitepeter@gmail.com>
Cc: Peter Crosthwaite <crosthwaite.peter@gmail.com>, Alistair Francis <alistair.francis@xilinx.com>, "qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>, Nathan Rossi <nathan@nathanrossi.com>

Peter,

On 09/13/2015 01:47 PM, Peter Maydell wrote:
> On 13 September 2015 at 21:22, Peter Crosthwaite
> <crosthwaitepeter@gmail.com> wrote:
>> On Sat, Sep 12, 2015 at 2:06 PM, Guenter Roeck <linux@roeck-us.net> 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 <linux@roeck-us.net>
>>>
>>
>> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
>>
>> 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.
>

Not sure I understand. Is this a NACK ?

Thanks,
Guenter