[U-Boot] [PATCH v2 2/2] net: eth-uclass: Support device tree MAC addresses

Thierry Reding thierry.reding at gmail.com
Wed Apr 17 15:03:41 UTC 2019


On Wed, Apr 17, 2019 at 02:49:22PM +0300, Grygorii Strashko wrote:
> 
> 
> On 16.04.19 19:24, Thierry Reding wrote:
> > From: Thierry Reding <treding at nvidia.com>
> > 
> > Add the standard Ethernet device tree bindings (imported from v5.0 of
> > the Linux kernel) and implement support for reading the MAC address for
> > Ethernet devices in the Ethernet uclass. If the "mac-address" property
> > exists, the MAC address will be parsed from that. If that property does
> > not exist, the "local-mac-address" property will be tried as fallback.
> > 
> > MAC addresses from device tree take precedence over the ones stored in
> > a network interface card's ROM.
> > 
> > Acked-by: Joe Hershberger <joe.hershberger at ni.com>
> > Signed-off-by: Thierry Reding <treding at nvidia.com>
> > ---
> > Changes in v2:
> > - use dev_read_u8_array_ptr()
> > 
> >  .../devicetree/bindings/net/ethernet.txt      | 66 +++++++++++++++++++
> >  net/eth-uclass.c                              | 26 +++++++-
> >  2 files changed, 89 insertions(+), 3 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/net/ethernet.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/net/ethernet.txt b/Documentation/devicetree/bindings/net/ethernet.txt
> > new file mode 100644
> > index 000000000000..cfc376bc977a
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/net/ethernet.txt
> > @@ -0,0 +1,66 @@
> > +The following properties are common to the Ethernet controllers:
> > +
> > +NOTE: All 'phy*' properties documented below are Ethernet specific. For the
> > +generic PHY 'phys' property, see
> > +Documentation/devicetree/bindings/phy/phy-bindings.txt.
> > +
> > +- local-mac-address: array of 6 bytes, specifies the MAC address that was
> > +  assigned to the network device;
> > +- mac-address: array of 6 bytes, specifies the MAC address that was last used by
> > +  the boot program; should be used in cases where the MAC address assigned to
> > +  the device by the boot program is different from the "local-mac-address"
> > +  property;
> > +- nvmem-cells: phandle, reference to an nvmem node for the MAC address;
> > +- nvmem-cell-names: string, should be "mac-address" if nvmem is to be used;
> > +- max-speed: number, specifies maximum speed in Mbit/s supported by the device;
> > +- max-frame-size: number, maximum transfer unit (IEEE defined MTU), rather than
> > +  the maximum frame size (there's contradiction in the Devicetree
> > +  Specification).
> > +- phy-mode: string, operation mode of the PHY interface. This is now a de-facto
> > +  standard property; supported values are:
> > +  * "internal"
> > +  * "mii"
> > +  * "gmii"
> > +  * "sgmii"
> > +  * "qsgmii"
> > +  * "tbi"
> > +  * "rev-mii"
> > +  * "rmii"
> > +  * "rgmii" (RX and TX delays are added by the MAC when required)
> > +  * "rgmii-id" (RGMII with internal RX and TX delays provided by the PHY, the
> > +     MAC should not add the RX or TX delays in this case)
> > +  * "rgmii-rxid" (RGMII with internal RX delay provided by the PHY, the MAC
> > +     should not add an RX delay in this case)
> > +  * "rgmii-txid" (RGMII with internal TX delay provided by the PHY, the MAC
> > +     should not add an TX delay in this case)
> > +  * "rtbi"
> > +  * "smii"
> > +  * "xgmii"
> > +  * "trgmii"
> > +  * "2000base-x",
> > +  * "2500base-x",
> > +  * "rxaui"
> > +  * "xaui"
> > +  * "10gbase-kr" (10GBASE-KR, XFI, SFI)
> > +- phy-connection-type: the same as "phy-mode" property but described in the
> > +  Devicetree Specification;
> > +- phy-handle: phandle, specifies a reference to a node representing a PHY
> > +  device; this property is described in the Devicetree Specification and so
> > +  preferred;
> > +- phy: the same as "phy-handle" property, not recommended for new bindings.
> > +- phy-device: the same as "phy-handle" property, not recommended for new
> > +  bindings.
> > +- rx-fifo-depth: the size of the controller's receive fifo in bytes. This
> > +  is used for components that can have configurable receive fifo sizes,
> > +  and is useful for determining certain configuration settings such as
> > +  flow control thresholds.
> > +- tx-fifo-depth: the size of the controller's transmit fifo in bytes. This
> > +  is used for components that can have configurable fifo sizes.
> > +- managed: string, specifies the PHY management type. Supported values are:
> > +  "auto", "in-band-status". "auto" is the default, it usess MDIO for
> > +  management if fixed-link is not specified.
> > +
> > +Child nodes of the Ethernet controller are typically the individual PHY devices
> > +connected via the MDIO bus (sometimes the MDIO bus controller is separate).
> > +They are described in the phy.txt file in this same directory.
> > +For non-MDIO PHY management see fixed-link.txt.
> > diff --git a/net/eth-uclass.c b/net/eth-uclass.c
> > index 4225aabf1fa1..c6d5ec013bd8 100644
> > --- a/net/eth-uclass.c
> > +++ b/net/eth-uclass.c
> > @@ -455,6 +455,23 @@ static int eth_pre_unbind(struct udevice *dev)
> >  	return 0;
> >  }
> >  
> > +static bool eth_dev_get_mac_address(struct udevice *dev, u8 mac[ARP_HLEN])
> > +{
> > +	const uint8_t *p;
> > +
> > +	p = dev_read_u8_array_ptr(dev, "mac-address", ARP_HLEN);
> > +	if (!p)
> > +		p = dev_read_u8_array_ptr(dev, "local-mac-address", ARP_HLEN);
> > +
> > +	if (!p) {
> > +		memset(mac, 0, ARP_HLEN);
> > +		return false;
> > +	}
> > +
> > +	memcpy(mac, p, ARP_HLEN);
> > +	return true;
> > +}
> 
> There are set of DT files in u-boot which have
> mac-address = [ 00 00 00 00 00 00 ];
> 
> How will it work for them? 
> Wouldn't cause unexpected skipping eth_get_ops(dev)->read_rom_hwaddr(dev) call?

Not sure. Are devices with mac-address set to all zeros in the DT
expected to have a ROM from which the address could be read? Seems like
if the MAC address can be read from ROM there shouldn't be a need to
have an extra mac-address property in device tree.

That said, if this really is a problem, I suppose we could add an
additional check to see if the MAC address read from DT is all zeros,
and if so attempt to read the ROM anyway.

Thierry

> 
> > +
> >  static int eth_post_probe(struct udevice *dev)
> >  {
> >  	struct eth_device_priv *priv = dev->uclass_priv;
> > @@ -489,9 +506,12 @@ static int eth_post_probe(struct udevice *dev)
> >  
> >  	priv->state = ETH_STATE_INIT;
> >  
> > -	/* Check if the device has a MAC address in ROM */
> > -	if (eth_get_ops(dev)->read_rom_hwaddr)
> > -		eth_get_ops(dev)->read_rom_hwaddr(dev);
> > +	/* Check if the device has a MAC address in device tree */
> > +	if (!eth_dev_get_mac_address(dev, pdata->enetaddr)) {
> > +		/* Check if the device has a MAC address in ROM */
> > +		if (eth_get_ops(dev)->read_rom_hwaddr)
> > +			eth_get_ops(dev)->read_rom_hwaddr(dev);
> > +	}
> >  
> >  	eth_env_get_enetaddr_by_index("eth", dev->seq, env_enetaddr);
> >  	if (!is_zero_ethaddr(env_enetaddr)) {
> > 
> 
> -- 
> Best regards,
> grygorii
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