netdev - [PATCH v2 16/29] net: add support for nvmem to eth_platform_get_mac

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Date:   Fri, 10 Aug 2018 10:05:13 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Jonathan Corbet <corbet@....net>, Sekhar Nori <nsekhar@...com>,
        Kevin Hilman <khilman@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Boris Brezillon <boris.brezillon@...tlin.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Richard Weinberger <richard@....at>,
        Grygorii Strashko <grygorii.strashko@...com>,
        "David S . Miller" <davem@...emloft.net>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Naren <naren.kernel@...il.com>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Lukas Wunner <lukas@...ner.de>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>,
        Sven Van Asbroeck <svendev@...x.com>,
        Paolo Abeni <pabeni@...hat.com>, Alban Bedel <albeu@...e.fr>,
        Rob Herring <robh@...nel.org>,
        David Lechner <david@...hnology.com>,
        Andrew Lunn <andrew@...n.ch>
Cc:     linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-i2c@...r.kernel.org,
        linux-mtd@...ts.infradead.org, linux-omap@...r.kernel.org,
        netdev@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: [PATCH v2 16/29] net: add support for nvmem to eth_platform_get_mac_address()

From: Bartosz Golaszewski <bgolaszewski@...libre.com>

Many non-DT platforms read the MAC address from EEPROM. Usually it's
either done with callbacks defined in board files or from SoC-specific
ethernet drivers.

In order to generalize this, try to read the MAC from nvmem in
eth_platform_get_mac_address() using a standard lookup name:
"mac-address".

Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
---
 net/ethernet/eth.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index d01dd55de037..f6f6af05fb58 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -54,6 +54,7 @@
 #include <linux/if_ether.h>
 #include <linux/of_net.h>
 #include <linux/pci.h>
+#include <linux/nvmem-consumer.h>
 #include <net/dst.h>
 #include <net/arp.h>
 #include <net/sock.h>
@@ -557,6 +558,39 @@ static int mac_address_from_arch(u8 *mac_addr)
 	return 0;
 }
 
+static int mac_address_from_nvmem(struct device *dev, u8 *mac_addr)
+{
+	const unsigned char *addr;
+	struct nvmem_cell *cell;
+	size_t alen;
+	int rv = 0;
+
+	cell = nvmem_cell_get(dev, "mac-address");
+	if (IS_ERR(cell))
+		return PTR_ERR(cell);
+
+	addr = nvmem_cell_read(cell, &alen);
+	if (IS_ERR(addr)) {
+		rv = PTR_ERR(addr);
+		goto put_nvmem;
+	}
+
+	if (alen != ETH_ALEN || !is_valid_ether_addr(addr)) {
+		rv = -ENODEV;
+		goto free_addr;
+	}
+
+	ether_addr_copy(mac_addr, addr);
+
+free_addr:
+	kfree(addr);
+
+put_nvmem:
+	nvmem_cell_put(cell);
+
+	return rv;
+}
+
 int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
 {
 	int rv;
@@ -569,6 +603,10 @@ int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
 	if (!rv)
 		return 0;
 
+	rv = mac_address_from_nvmem(dev, mac_addr);
+	if (!rv)
+		return 0;
+
 	return -ENODEV;
 }
 EXPORT_SYMBOL(eth_platform_get_mac_address);
-- 
2.18.0