[PATCH net 1/2] net: dsa: mt7530: fix corrupt frames using trgmii on 40 MHz XTAL MT7621

[Florian Fainelli]

On 5/1/2023 5:15 AM, arinc9.unal at gmail.com wrote:
> From: Arınç ÜNAL <arinc.unal at arinc9.com>
> 
> The multi-chip module MT7530 switch with a 40 MHz oscillator on the
> MT7621AT, MT7621DAT, and MT7621ST SoCs forwards corrupt frames using
> trgmii.
> 
> This is caused by the assumption that MT7621 SoCs have got 150 MHz PLL,
> hence using the ncpo1 value, 0x0780.
> 
> My testing shows this value works on Unielec U7621-06, Bartel's testing
> shows it won't work on Hi-Link HLK-MT7621A and Netgear WAC104. All devices
> tested have got 40 MHz oscillators.
> 
> Using the value for 125 MHz PLL, 0x0640, works on all boards at hand. The
> definitions for 125 MHz PLL exist on the Banana Pi BPI-R2 BSP source code
> whilst 150 MHz PLL don't.
> 
> Forwarding frames using trgmii on the MCM MT7530 switch with a 25 MHz
> oscillator on the said MT7621 SoCs works fine because the ncpo1 value
> defined for it is for 125 MHz PLL.
> 
> Change the 150 MHz PLL comment to 125 MHz PLL, and use the 125 MHz PLL
> ncpo1 values for both oscillator frequencies.
> 
> Link: https://github.com/BPI-SINOVOIP/BPI-R2-bsp/blob/81d24bbce7d99524d0771a8bdb2d6663e4eb4faa/u-boot-mt/drivers/net/rt2880_eth.c#L2195
> Fixes: 7ef6f6f8d237 ("net: dsa: mt7530: Add MT7621 TRGMII mode support")
> Tested-by: Bartel Eerdekens <bartel.eerdekens at constell8.be>
> Tested-by: Arınç ÜNAL <arinc.unal at arinc9.com>
> Signed-off-by: Arınç ÜNAL <arinc.unal at arinc9.com>

Reviewed-by: Florian Fainelli <f.fainelli at gmail.com>
-- 
Florian