| Message ID | 20240311135112.2642491-4-enachman@marvell.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Fix prestera driver fail to probe twice | expand |
On 3/11/24 14:51, Elad Nachman wrote: > From: Elad Nachman <enachman@marvell.com> > > Since each switchport MAC address uses the switch base mac address > and adds the physical port number to it, > Force the last byte of the switch base mac address to be at > least 128, so when adding to it, we will not wrap around the to be at *most* 128 > previous (more significant) mac address byte, resulting in a > warning message. > > Signed-off-by: Elad Nachman <enachman@marvell.com> > --- > drivers/net/ethernet/marvell/prestera/prestera_main.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/marvell/prestera/prestera_main.c b/drivers/net/ethernet/marvell/prestera/prestera_main.c > index bcaa8ea27b49..e17b1a24fe18 100644 > --- a/drivers/net/ethernet/marvell/prestera/prestera_main.c > +++ b/drivers/net/ethernet/marvell/prestera/prestera_main.c > @@ -859,7 +859,9 @@ static int prestera_switch_set_base_mac_addr(struct prestera_switch *sw) > if (sw->np) > ret = of_get_mac_address(sw->np, sw->base_mac); > if (!is_valid_ether_addr(sw->base_mac) || ret) { > - eth_random_addr(sw->base_mac); > + do { > + eth_random_addr(sw->base_mac); > + } while (sw->base_mac[5] > 0x80); Instead of this loop, that uses 6 bytes of random data at each step, I would just fix the last byte. Either by calling get_random_u8() in a loop, or perhaps better, just toggle of MSB unconditionally: sw->base_mac[5] &= ~0x80; // or '&= 127' what would change your condition in commit message to "to be at most 127", but I think that should be fine, granted simpler code. > dev_info(prestera_dev(sw), "using random base mac address\n"); > } >
On Mon, Mar 11, 2024 at 03:51:12PM +0200, Elad Nachman wrote: > From: Elad Nachman <enachman@marvell.com> > > Since each switchport MAC address uses the switch base mac address > and adds the physical port number to it, > Force the last byte of the switch base mac address to be at > least 128, so when adding to it, we will not wrap around the > previous (more significant) mac address byte, resulting in a > warning message. It is not clear to me what the real problem is here. Does the hardware require that the MAC addresses always have the same upper 5 bytes? Andrew
diff --git a/drivers/net/ethernet/marvell/prestera/prestera_main.c b/drivers/net/ethernet/marvell/prestera/prestera_main.c index bcaa8ea27b49..e17b1a24fe18 100644 --- a/drivers/net/ethernet/marvell/prestera/prestera_main.c +++ b/drivers/net/ethernet/marvell/prestera/prestera_main.c @@ -859,7 +859,9 @@ static int prestera_switch_set_base_mac_addr(struct prestera_switch *sw) if (sw->np) ret = of_get_mac_address(sw->np, sw->base_mac); if (!is_valid_ether_addr(sw->base_mac) || ret) { - eth_random_addr(sw->base_mac); + do { + eth_random_addr(sw->base_mac); + } while (sw->base_mac[5] > 0x80); dev_info(prestera_dev(sw), "using random base mac address\n"); }