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of_net: Implement of_get_nvmem_mac_address helper

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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@topic.nl>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mike Looijmans 2018-03-29 07:29:48 +02:00 committed by David S. Miller
parent 64e828dfc4
commit 9217e566bd
3 changed files with 48 additions and 0 deletions
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2
Documentation/devicetree/bindings/net/ethernet.txt
View File

@ -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

40
drivers/of/of_net.c
View File

@ -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 < ETH_ALEN || !is_valid_ether_addr(mac)) {
ret = -EINVAL;
} else {
ether_addr_copy(addr, mac);
ret = 0;
}
kfree(mac);
return ret;
}
EXPORT_SYMBOL(of_get_nvmem_mac_address);

6
include/linux/of_net.h
View File

@ -13,6 +13,7 @@
struct net_device;
extern int of_get_phy_mode(struct device_node *np);
extern const void *of_get_mac_address(struct device_node *np);
extern int of_get_nvmem_mac_address(struct device_node *np, void *addr);
extern struct net_device *of_find_net_device_by_node(struct device_node *np);
#else
static inline int of_get_phy_mode(struct device_node *np)
@ -25,6 +26,11 @@ static inline const void *of_get_mac_address(struct device_node *np)
return NULL;
}
static inline int of_get_nvmem_mac_address(struct device_node *np, void *addr)
{
return -ENODEV;
}
static inline struct net_device *of_find_net_device_by_node(struct device_node *np)
{
return NULL;