Re: [PATCH v3 1/2] of_net: Implement of_get_nvmem_mac_address helper

[Mike Looijmans]

ïOn 28-03-18 00:50, Florian Fainelli wrote:
> On 03/27/2018 02:52 AM, Mike Looijmans wrote:
> > It's common practice to store MAC addresses for network interfaces into
> > nvmem devices. However the code to actually do this in the kernel lacks,
> > so this patch adds of_get_nvmem_mac_address() for drivers to obtain the
> > address from an nvmem cell provider.
> >
> > This is particulary useful on devices where the ethernet interface cannot
> > be configured by the bootloader, for example because it's in an FPGA.
> >
> > Signed-off-by: Mike Looijmans <mike.looijmans@xxxxxxxx>
> > ---
> >   Documentation/devicetree/bindings/net/ethernet.txt |  2 ++
> >   drivers/of/of_net.c                                | 40 ++++++++++++++++++++++
> >   include/linux/of_net.h                             |  6 ++++
> >   3 files changed, 48 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/net/ethernet.txt b/Documentation/devicetree/bindings/net/ethernet.txt
> > index 2974e63..cfc376b 100644
> > --- a/Documentation/devicetree/bindings/net/ethernet.txt
> > +++ b/Documentation/devicetree/bindings/net/ethernet.txt
> > @@ -10,6 +10,8 @@ Documentation/devicetree/bindings/phy/phy-bindings.txt.
> >     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
> > diff --git a/drivers/of/of_net.c b/drivers/of/of_net.c
> > index d820f3e..1c5d372 100644
> > --- a/drivers/of/of_net.c
> > +++ b/drivers/of/of_net.c
> > @@ -7,6 +7,7 @@
> >    */
> >   #include <linux/etherdevice.h>
> >   #include <linux/kernel.h>
> > +#include <linux/nvmem-consumer.h>
> >   #include <linux/of_net.h>
> >   #include <linux/phy.h>
> >   #include <linux/export.h>
> > @@ -80,3 +81,42 @@ const void *of_get_mac_address(struct device_node *np)
> >   	return of_get_mac_addr(np, "address");
> >   }
> >   EXPORT_SYMBOL(of_get_mac_address);
> > +
> > +/**
> > + * Obtain the MAC address from an nvmem provider named 'mac-address' through
> > + * device tree.
> > + * On success, copies the new address into memory pointed to by addr and
> > + * returns 0. Returns a negative error code otherwise.
> > + * @np:		Device tree node containing the nvmem-cells phandle
> > + * @addr:	Pointer to receive the MAC address using ether_addr_copy()
> > + */
> > +int of_get_nvmem_mac_address(struct device_node *np, void *addr)
> > +{
> > +	struct nvmem_cell *cell;
> > +	const void *mac;
> > +	size_t len;
> > +	int ret;
> > +
> > +	cell = of_nvmem_cell_get(np, "mac-address");
> > +	if (IS_ERR(cell))
> > +		return PTR_ERR(cell);
> > +
> > +	mac = nvmem_cell_read(cell, &len);
> > +
> > +	nvmem_cell_put(cell);
> > +
> > +	if (IS_ERR(mac))
> > +		return PTR_ERR(mac);
> > +
> > +	if (len < 6 || !is_valid_ether_addr(mac)) {
> > +		ret = -EINVAL;
>
> Just one nit here, can you use ETH_ALEN instead of 6? With that fixed:
>
> Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>

Ok, implemented and tested it, and v4 is on the way with that change.


Kind regards,

Mike Looijmans
System Expert

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