Re: [PATCH] hw/arm/xlnx: Fix PHY address for xilinx-zynq-a9

[Guenter Roeck]

On 5/5/21 6:58 PM, Bin Meng wrote:
> Hi Guenter,
> 
> On Tue, May 4, 2021 at 8:41 PM Guenter Roeck <linux@roeck-us.net> wrote:
>>
>> Commit dfc388797cc4 ("hw/arm: xlnx: Set all boards' GEM 'phy-addr'
>> property value to 23") configured the PHY address for xilinx-zynq-a9
>> to 23. When trying to boot xilinx-zynq-a9 with zynq-zc702.dtb or
>> zynq-zc706.dtb, this results in the following error message when
>> trying to use the Ethernet interface.
>>
>> macb e000b000.ethernet eth0: Could not attach PHY (-19)
>>
>> The devicetree files for ZC702 and ZC706 configure PHY address 7. The
>> documentation for the ZC702 and ZC706 evaluation boards suggest that the
>> PHY address is 7, not 23. Other boards use PHY address 0, 1, 3, or 7.
>> I was unable to find a documentation or a devicetree file suggesting
>> or using PHY address 23.
> 
> I can't find one neither :(
> 
>> The Ethernet interface starts working with
>> zynq-zc702.dtb and zynq-zc706.dtb when setting the PHY address to 7,
>> so let's use it.
>>
>> Cc: Bin Meng <bin.meng@windriver.com>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> ---
>>  hw/arm/xilinx_zynq.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/hw/arm/xilinx_zynq.c b/hw/arm/xilinx_zynq.c
>> index 8db6cfd47f..5ac0294f9e 100644
>> --- a/hw/arm/xilinx_zynq.c
>> +++ b/hw/arm/xilinx_zynq.c
>> @@ -119,7 +119,7 @@ static void gem_init(NICInfo *nd, uint32_t base, 
>> qemu_irq irq)
>>          qemu_check_nic_model(nd, TYPE_CADENCE_GEM);
>>          qdev_set_nic_properties(dev, nd);
>>      }
>> -    object_property_set_int(OBJECT(dev), "phy-addr", 23, &error_abort);
>> +    object_property_set_int(OBJECT(dev), "phy-addr", 7, &error_abort);
>>      s = SYS_BUS_DEVICE(dev);
>>      sysbus_realize_and_unref(s, &error_fatal);
>>      sysbus_mmio_map(s, 0, base);
>> --
> 
> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
> 
> While we are here, could you please create a doc for the target you
> are testing with Linux/U-Boot/etc?
> 
> I was having a hard time booting upstream U-Boot/Linux on QEMU zynqmp before.
> 

Everything I have is in my repository at
    https://github.com/groeck/linux-build-test
My clone of qemu is at
    https://github.com/groeck/qemu

The v6.0.0-local branch in the qemu repository is probably the most relevant.
There are two caveats when trying to boot zynqmp images:
- You may need commit 9bfbe02879 from that branch to boot Linux directly,
  ie without u-boot. That patch was rejected a long time ago (the argument,
  if I recall correctly, was that u-boot should set the clock rates as
  needed).
- Booting zynqmp based images on arm64 with linux 5.6 and later doesn't work
  anymore. This is due to Linux commit 9c8a47b484ed ("arm64: dts: xilinx:
  Add the clock nodes for zynqmp"). Unfortunately, those clocks are tied
  to zynqmq firmware which is not emulated by qemu, so all the drivers
  needed to do anything useful in Linux won't load.

Hope this helps,
Guenter