of: net: pass the dst buffer to of_get_mac_address()

of_get_mac_address() returns a "const void*" pointer to a MAC address.
Lately, support to fetch the MAC address by an NVMEM provider was added.
But this will only work with platform devices. It will not work with
PCI devices (e.g. of an integrated root complex) and esp. not with DSA
ports.

There is an of_* variant of the nvmem binding which works without
devices. The returned data of a nvmem_cell_read() has to be freed after
use. On the other hand the return of_get_mac_address() points to some
static data without a lifetime. The trick for now, was to allocate a
device resource managed buffer which is then returned. This will only
work if we have an actual device.

Change it, so that the caller of of_get_mac_address() has to supply a
buffer where the MAC address is written to. Unfortunately, this will
touch all drivers which use the of_get_mac_address().

Usually the code looks like:

  const char *addr;
  addr = of_get_mac_address(np);
  if (!IS_ERR(addr))
    ether_addr_copy(ndev->dev_addr, addr);

This can then be simply rewritten as:

  of_get_mac_address(np, ndev->dev_addr);

Sometimes is_valid_ether_addr() is used to test the MAC address.
of_get_mac_address() already makes sure, it just returns a valid MAC
address. Thus we can just test its return code. But we have to be
careful if there are still other sources for the MAC address before the
of_get_mac_address(). In this case we have to keep the
is_valid_ether_addr() call.

The following coccinelle patch was used to convert common cases to the
new style. Afterwards, I've manually gone over the drivers and fixed the
return code variable: either used a new one or if one was already
available use that. Mansour Moufid, thanks for that coccinelle patch!

<spml>
@a@
identifier x;
expression y, z;
@@
- x = of_get_mac_address(y);
+ x = of_get_mac_address(y, z);
  <...
- ether_addr_copy(z, x);
  ...>

@@
identifier a.x;
@@
- if (<+... x ...+>) {}

@@
identifier a.x;
@@
  if (<+... x ...+>) {
      ...
  }
- else {}

@@
identifier a.x;
expression e;
@@
- if (<+... x ...+>@e)
-     {}
- else
+ if (!(e))
      {...}

@@
expression x, y, z;
@@
- x = of_get_mac_address(y, z);
+ of_get_mac_address(y, z);
  ... when != x
</spml>

All drivers, except drivers/net/ethernet/aeroflex/greth.c, were
compile-time tested.

Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 12 insertions, 27 deletions

diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c
index ca1681aa951a..d207bfcaf31d 100644
--- a/drivers/net/ethernet/marvell/mv643xx_eth.c
+++ b/drivers/net/ethernet/marvell/mv643xx_eth.c
@@ -2702,7 +2702,6 @@ static int mv643xx_eth_shared_of_add_port(struct platform_device *pdev,
 	struct platform_device *ppdev;
 	struct mv643xx_eth_platform_data ppd;
 	struct resource res;
-	const char *mac_addr;
 	int ret;
 	int dev_num = 0;
 
@@ -2733,9 +2732,7 @@ static int mv643xx_eth_shared_of_add_port(struct platform_device *pdev,
 		return -EINVAL;
 	}
 
-	mac_addr = of_get_mac_address(pnp);
-	if (!IS_ERR(mac_addr))
-		ether_addr_copy(ppd.mac_addr, mac_addr);
+	of_get_mac_address(pnp, ppd.mac_addr);
 
 	mv643xx_eth_property(pnp, "tx-queue-size", ppd.tx_queue_size);
 	mv643xx_eth_property(pnp, "tx-sram-addr", ppd.tx_sram_addr);
diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index f20dfd1d7a6b..7d5cd9bc6c99 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -5141,7 +5141,6 @@ static int mvneta_probe(struct platform_device *pdev)
 	struct net_device *dev;
 	struct phylink *phylink;
 	struct phy *comphy;
-	const char *dt_mac_addr;
 	char hw_mac_addr[ETH_ALEN];
 	phy_interface_t phy_mode;
 	const char *mac_from;
@@ -5237,10 +5236,9 @@ static int mvneta_probe(struct platform_device *pdev)
 		goto err_free_ports;
 	}
 
-	dt_mac_addr = of_get_mac_address(dn);
-	if (!IS_ERR(dt_mac_addr)) {
+	err = of_get_mac_address(dn, dev->dev_addr);
+	if (!err) {
 		mac_from = "device tree";
-		ether_addr_copy(dev->dev_addr, dt_mac_addr);
 	} else {
 		mvneta_get_mac_addr(pp, hw_mac_addr);
 		if (is_valid_ether_addr(hw_mac_addr)) {
diff --git a/drivers/net/ethernet/marvell/prestera/prestera_main.c b/drivers/net/ethernet/marvell/prestera/prestera_main.c
index 25dd903a3e92..f08c420a5803 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_main.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_main.c
@@ -456,20 +456,17 @@ static int prestera_switch_set_base_mac_addr(struct prestera_switch *sw)
 {
 	struct device_node *base_mac_np;
 	struct device_node *np;
-	const char *base_mac;
+	int ret;
 
 	np = of_find_compatible_node(NULL, NULL, "marvell,prestera");
 	base_mac_np = of_parse_phandle(np, "base-mac-provider", 0);
 
-	base_mac = of_get_mac_address(base_mac_np);
-	of_node_put(base_mac_np);
-	if (!IS_ERR(base_mac))
-		ether_addr_copy(sw->base_mac, base_mac);
-
-	if (!is_valid_ether_addr(sw->base_mac)) {
+	ret = of_get_mac_address(base_mac_np, sw->base_mac);
+	if (ret) {
 		eth_random_addr(sw->base_mac);
 		dev_info(prestera_dev(sw), "using random base mac address\n");
 	}
+	of_node_put(base_mac_np);
 
 	return prestera_hw_switch_mac_set(sw, sw->base_mac);
 }
diff --git a/drivers/net/ethernet/marvell/pxa168_eth.c b/drivers/net/ethernet/marvell/pxa168_eth.c
index 3712e1786091..e967867828d8 100644
--- a/drivers/net/ethernet/marvell/pxa168_eth.c
+++ b/drivers/net/ethernet/marvell/pxa168_eth.c
@@ -1392,7 +1392,6 @@ static int pxa168_eth_probe(struct platform_device *pdev)
 	struct resource *res;
 	struct clk *clk;
 	struct device_node *np;
-	const unsigned char *mac_addr = NULL;
 	int err;
 
 	printk(KERN_NOTICE "PXA168 10/100 Ethernet Driver\n");
@@ -1435,12 +1434,8 @@ static int pxa168_eth_probe(struct platform_device *pdev)
 
 	INIT_WORK(&pep->tx_timeout_task, pxa168_eth_tx_timeout_task);
 
-	if (pdev->dev.of_node)
-		mac_addr = of_get_mac_address(pdev->dev.of_node);
-
-	if (!IS_ERR_OR_NULL(mac_addr)) {
-		ether_addr_copy(dev->dev_addr, mac_addr);
-	} else {
+	err = of_get_mac_address(pdev->dev.of_node, dev->dev_addr);
+	if (err) {
 		/* try reading the mac address, if set by the bootloader */
 		pxa168_eth_get_mac_address(dev, dev->dev_addr);
 		if (!is_valid_ether_addr(dev->dev_addr)) {
diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c
index 68c154d715d6..222c32367b2c 100644
--- a/drivers/net/ethernet/marvell/sky2.c
+++ b/drivers/net/ethernet/marvell/sky2.c
@@ -4728,7 +4728,7 @@ static struct net_device *sky2_init_netdev(struct sky2_hw *hw, unsigned port,
 {
 	struct sky2_port *sky2;
 	struct net_device *dev = alloc_etherdev(sizeof(*sky2));
-	const void *iap;
+	int ret;
 
 	if (!dev)
 		return NULL;
@@ -4798,10 +4798,8 @@ static struct net_device *sky2_init_netdev(struct sky2_hw *hw, unsigned port,
 	 * 1) from device tree data
 	 * 2) from internal registers set by bootloader
 	 */
-	iap = of_get_mac_address(hw->pdev->dev.of_node);
-	if (!IS_ERR(iap))
-		ether_addr_copy(dev->dev_addr, iap);
-	else
+	ret = of_get_mac_address(hw->pdev->dev.of_node, dev->dev_addr);
+	if (ret)
 		memcpy_fromio(dev->dev_addr, hw->regs + B2_MAC_1 + port * 8,
 			      ETH_ALEN);