From 4932c5d80153c336c77dbe8d7af9f8fdd879d01f Mon Sep 17 00:00:00 2001 From: Michael Walle Date: Mon, 12 Apr 2021 19:47:17 +0200 Subject: [PATCH] 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! @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 All drivers, except drivers/net/ethernet/aeroflex/greth.c, were compile-time tested. Suggested-by: Andrew Lunn Signed-off-by: Michael Walle Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller --- eeprom.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/eeprom.c b/eeprom.c index cc74c372d..3873b6a97 100644 --- a/eeprom.c +++ b/eeprom.c @@ -91,15 +91,9 @@ mt76_eeprom_override(struct mt76_phy *phy) { struct mt76_dev *dev = phy->dev; -#ifdef CONFIG_OF struct device_node *np = dev->dev->of_node; - const u8 *mac = NULL; - if (np) - mac = of_get_mac_address(np); - if (!IS_ERR_OR_NULL(mac)) - ether_addr_copy(phy->macaddr, mac); -#endif + of_get_mac_address(np, phy->macaddr); if (!is_valid_ether_addr(phy->macaddr)) { eth_random_addr(phy->macaddr);