Re: [PATCH 1/5] arm64: zynqmp: Add firmware DT node

[Michal Simek]

On 09. 12. 19 8:48, Edgar E. Iglesias wrote:
> On Sun, Dec 08, 2019 at 11:19:33PM -0800, Guenter Roeck wrote:
>> On 12/8/19 10:42 PM, Michal Simek wrote:
>>> Hi, +Edgar
>>>
>>>
>>> On 08. 12. 19 23:38, Guenter Roeck wrote:
>>>> On Fri, Oct 18, 2019 at 06:07:31PM +0200, Michael Tretter wrote:
>>>>> From: Rajan Vaja <address@hidden>
>>>>>
>>>>> Add firmware DT node in ZynqMP device tree. This node
>>>>> uses bindings as per new firmware interface driver.
>>>>>
>>>>> Signed-off-by: Rajan Vaja <address@hidden>
>>>>> Signed-off-by: Michal Simek <address@hidden>
>>>>> Signed-off-by: Michael Tretter <address@hidden>
>>>>
>>>> With this patch applied in the mainline kernel, the qemu xlnx-zcu102
>>>> emulation crashes (see below). Any idea what it might take to get
>>>> qemu back to working ?
>>>
>>> Driver talks through ATF to PMU unit(microblaze). I don't think A53+MB
>>> concept is working with mainline qemu. But crash is too hard. It should
> 
> Yes, QEMU doesn't support the Cortex-A53s along with the PMU MicroBlaze.
> 
> My workaround when using upstream QEMU is a modified DT without the PMU 
> firmware
> and with fixed-clock nodes.

IIRC you said that there is still discussion how to upstream this.
Fixed clock should work for u-boot too. But SPL reads that registers
directly. Are you implementing them with any default values?

> 
> 
>>> be no response from PMU and then this panic.
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/firmware/xilinx/zynqmp.c?h=v5.5-rc1#n728
>>>
>>
>> Isn't that a bit harsh too ? Normally one would print an error message
>> and abort driver instantiation.
> 
> I agree, it would be nice if ATF & kernel drivers would somehow handle
> this more gracefully.

Rajan: can you please take a look at it?

Thanks,
Michal