From: Arınç ÜNAL arinc.unal@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/81d24bbce7d99524d0771a8bdb2d... Fixes: 7ef6f6f8d237 ("net: dsa: mt7530: Add MT7621 TRGMII mode support") Cc: stable@vger.kernel.org Tested-by: Bartel Eerdekens bartel.eerdekens@constell8.be Tested-by: Arınç ÜNAL arinc.unal@arinc9.com Signed-off-by: Arınç ÜNAL arinc.unal@arinc9.com --- drivers/net/dsa/mt7530.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c index c680873819b0..7d9f9563dbda 100644 --- a/drivers/net/dsa/mt7530.c +++ b/drivers/net/dsa/mt7530.c @@ -426,9 +426,9 @@ mt7530_pad_clk_setup(struct dsa_switch *ds, phy_interface_t interface) else ssc_delta = 0x87; if (priv->id == ID_MT7621) { - /* PLL frequency: 150MHz: 1.2GBit */ + /* PLL frequency: 125MHz: 1.0GBit */ if (xtal == HWTRAP_XTAL_40MHZ) - ncpo1 = 0x0780; + ncpo1 = 0x0640; if (xtal == HWTRAP_XTAL_25MHZ) ncpo1 = 0x0a00; } else { /* PLL frequency: 250MHz: 2.0Gbit */