[U-Boot] [PATCH 18/26] net: mt7628-eth: add support to isolate LAN/WAN ports

[Weijie Gao <weijie.gao@mediatek.com>]

On Wed, 2019-08-28 at 15:46 +0200, Stefan Roese wrote:
> On 28.08.19 08:38, Weijie Gao wrote:
> > This patch add support for mt7628-eth to isolate LAN/WAN ports mainly to
> 
> Nitpicking:
> 
> s/add/adds
> 
> > prevent LAN devices from getting IP address from WAN.
> > 
> > Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
> > ---
> >   drivers/net/mt7628-eth.c | 32 ++++++++++++++++++++++++++++++++
> >   1 file changed, 32 insertions(+)
> > 
> > diff --git a/drivers/net/mt7628-eth.c b/drivers/net/mt7628-eth.c
> > index 8ca2c66edb..1215b24eaf 100644
> > --- a/drivers/net/mt7628-eth.c
> > +++ b/drivers/net/mt7628-eth.c
> > @@ -57,6 +57,11 @@
> >   /* Ethernet switch register */
> >   #define MT7628_SWITCH_FCT0	0x0008
> >   #define MT7628_SWITCH_PFC1	0x0014
> > +#define MT7628_SWITCH_PVIDC0	0x0040
> > +#define MT7628_SWITCH_PVIDC1	0x0044
> > +#define MT7628_SWITCH_PVIDC2	0x0048
> > +#define MT7628_SWITCH_PVIDC3	0x004c
> > +#define MT7628_SWITCH_VMSC0	0x0070
> >   #define MT7628_SWITCH_FPA	0x0084
> >   #define MT7628_SWITCH_SOCPC	0x008c
> >   #define MT7628_SWITCH_POC0	0x0090
> > @@ -137,6 +142,8 @@ struct mt7628_eth_dev {
> >   	int tx_dma_idx;
> >   
> >   	struct reset_ctl	rst_ephy;
> > +
> > +	int wan_port;
> >   };
> >   
> >   static int mt7628_eth_free_pkt(struct udevice *dev, uchar *packet, int length);
> > @@ -269,6 +276,9 @@ static void mt7628_ephy_init(struct mt7628_eth_dev *priv)
> >   static void rt305x_esw_init(struct mt7628_eth_dev *priv)
> >   {
> >   	void __iomem *base = priv->eth_sw_base;
> > +	void __iomem *reg;
> > +	u32 val = 0, pvid;
> > +	int i;
> >   
> >   	/*
> >   	 * FC_RLS_TH=200, FC_SET_TH=160
> > @@ -290,6 +300,25 @@ static void rt305x_esw_init(struct mt7628_eth_dev *priv)
> >   	/* 1us cycle number=125 (FE's clock=125Mhz) */
> >   	writel(0x7d000000, base + MT7628_SWITCH_BMU_CTRL);
> >   
> > +	/* LAN/WAN partition, WAN port will be unusable in u-boot network */
> > +	if (priv->wan_port >= 0 && priv->wan_port < 6) {
> > +		for (i = 0; i < 8; i++) {
> > +			pvid = i == priv->wan_port ? 2 : 1;
> > +			reg = base + MT7628_SWITCH_PVIDC0 + (i / 2) * 4;
> > +			if (i % 2 == 0) {
> > +				val = pvid;
> > +			} else {
> > +				val |= (pvid << 12);
> > +				writel(val, reg);
> > +			}
> > +		}
> > +
> > +		val = 0xffff407f;
> > +		val |= 1 << (8 + priv->wan_port);
> > +		val &= ~(1 << priv->wan_port);
> > +		writel(val, base + MT7628_SWITCH_VMSC0);
> > +	}
> > +
> >   	/* Reset PHY */
> >   	reset_assert(&priv->rst_ephy);
> >   	reset_deassert(&priv->rst_ephy);
> > @@ -529,6 +558,9 @@ static int mt7628_eth_probe(struct udevice *dev)
> >   		return ret;
> >   	}
> >   
> > +	/* WAN port will be isolated from LAN ports */
> > +	priv->wan_port = dev_read_u32_default(dev, "mediatek,wan-port", -1);
> 
> Where is this DT property documented? I can't find it in Linux either. We should
> find some other way to reference the ports. Perhaps something like done in
> Linux DSA?
> 
> What is your reasoning for this change? Which board / target are you supporting
> with this new code?
> 
> Thanks,
> Stefan

This is for the situation mt76x8 used as a router with more than one
ethernet ports.

The mt76x8 has one switch, both LAN ports and WAN port come from it.
By default the switch is in dumb switch mode after power on, which means
any packet can be broadcast to any port with out restriction.

If a router powered on with both LAN cable and WAN cable plugged in, the
LAN device may get IP address from upstream before the kernel setting
the correct VLAN. However the IP address which is supposed to be get by
the router itself. This is what we don't want to be happened.

If we're using a switch like mt7530, we can use the port matrix to
isolate each port to solve this problem perfectly. You can refer to
mtk_eth.c, at the end of mt7530_setup().

However mt76x8 switch core does not have the port matrix functionality,
that means the VLAN must be used.

Considering you are using OpenWrt. The switch registers a switch object
to swconfig (OpenWrt's switch framework). So the VLAN is set by
swconfig, not the ethernet driver.

However u-boot does not have a switch framework, I have to add this
directly to the ethernet driver.

The WAN port, depending on the design of the router, can be any ports
from 0 to 4. So I use "mediatek,wan-port" to specify the WAN port.

If "mediatek,wan-port" is set, the WAN port is isolated from the switch.
Otherwise all ports are interconnected.

Weijie