[PATCH v2 16/29] net: add support for nvmem to eth_platform_get_mac_address()

From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Jonathan Corbet <corbet@lwn.net>, Sekhar Nori <nsekhar@ti.com>,
	Kevin Hilman <khilman@kernel.org>,
	Russell King <linux@armlinux.org.uk>,
	Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Brian Norris <computersforpeace@gmail.com>,
	Boris Brezillon <boris.brezillon@bootlin.com>,
	Marek Vasut <marek.vasut@gmail.com>,
	Richard Weinberger <richard@nod.at>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	"David S . Miller" <davem@davemloft.net>,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	Naren <naren.kernel@gmail.com>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Lukas Wunner <lukas@wunner.de>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>,
	Sven Van Asbroeck <svendev@arcx.com>,
	Paolo Abeni <pabeni@redhat.com>, Alban Bedel <albeu@free.fr>,
	Rob Herring <robh@kernel.org>,
	David Lechner <david@lechnology.com>,
	Andrew Lunn <andrew@lunn.ch>
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org,
	linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org,
	netdev@vger.kernel.org,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: [PATCH v2 16/29] net: add support for nvmem to eth_platform_get_mac_address()
Date: Fri, 10 Aug 2018 10:05:13 +0200	[thread overview]
Message-ID: <20180810080526.27207-17-brgl@bgdev.pl> (raw)
In-Reply-To: <20180810080526.27207-1-brgl@bgdev.pl>

From: Bartosz Golaszewski <bgolaszewski@baylibre.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@baylibre.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

