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

Grygorii Strashko grygorii.strashko at ti.com
Thu Apr 18 16:30:05 UTC 2019



On 17.04.19 18:03, Thierry Reding wrote:
> 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.


correct, for TI boards it's expected to populate mac address in DT by u-boot,
so linux can use it.

Not sure why there are zero "mac-address" property in DT - probably due to
some historical reasons.


> 
> 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.

I think, the linux code can be used as reference here:

static const void *of_get_mac_addr(struct device_node *np, const char *name)
{
	struct property *pp = of_find_property(np, name, NULL);

	if (pp && pp->length == ETH_ALEN && is_valid_ether_addr(pp->value))

^^^^ there is additional check is_valid_ether_addr()

		return pp->value;
	return NULL;
}



>>
>>> +
>>>  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

-- 
Best regards,
grygorii


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