Re: [PATCH v2] net: davicom: dm9000: allow to pass MAC address through mac_addr module parameter

From: Paul Cercueil
Date: Fri Feb 14 2020 - 13:47:54 EST


Hi Nikolaus,

What I'd suggest is to write a NVMEM driver for the efuse and retrieve the MAC address cleanly with nvmem_get_mac_address().

It shouldn't be hard to do (there's already code for it in the non-upstream 3.18 kernel for the CI20) and you remove the dependency on uboot.

-Paul


Le ven., févr. 14, 2020 at 17:07, H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> a écrit :
The MIPS Ingenic CI20 board is shipped with a quite old u-boot
(ci20-v2013.10 see https://elinux.org/CI20_Dev_Zone). This passes
the MAC address through dm9000.mac_addr=xx:xx:xx:xx:xx:xx
kernel module parameter to give the board a fixed MAC address.

This is not processed by the dm9000 driver which assigns a random
MAC address on each boot, making DHCP assign a new IP address
each time.

So we add a check for the mac_addr module parameter as a last
resort before assigning a random one. This mechanism can also
be used outside of u-boot to provide a value through modprobe
config.

To parse the MAC address in a new function get_mac_addr() we
use an copy adapted from the ksz884x.c driver which provides
the same functionality.

Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
---
drivers/net/ethernet/davicom/dm9000.c | 42 +++++++++++++++++++++++++++
1 file changed, 42 insertions(+)

diff --git a/drivers/net/ethernet/davicom/dm9000.c b/drivers/net/ethernet/davicom/dm9000.c
index 1ea3372775e6..7402030b0352 100644
--- a/drivers/net/ethernet/davicom/dm9000.c
+++ b/drivers/net/ethernet/davicom/dm9000.c
@@ -1409,6 +1409,43 @@ static struct dm9000_plat_data *dm9000_parse_dt(struct device *dev)
return pdata;
}

+static char *mac_addr = ":";
+module_param(mac_addr, charp, 0);
+MODULE_PARM_DESC(mac_addr, "MAC address");
+
+static void get_mac_addr(struct net_device *ndev, char *macaddr)
+{
+ int i = 0;
+ int j = 0;
+ int got_num = 0;
+ int num = 0;
+
+ while (j < ETH_ALEN) {
+ if (macaddr[i]) {
+ int digit;
+
+ got_num = 1;
+ digit = hex_to_bin(macaddr[i]);
+ if (digit >= 0)
+ num = num * 16 + digit;
+ else if (':' == macaddr[i])
+ got_num = 2;
+ else
+ break;
+ } else if (got_num) {
+ got_num = 2;
+ } else {
+ break;
+ }
+ if (got_num == 2) {
+ ndev->dev_addr[j++] = (u8)num;
+ num = 0;
+ got_num = 0;
+ }
+ i++;
+ }
+}
+
/*
* Search DM9000 board, allocate space and register it
*/
@@ -1679,6 +1716,11 @@ dm9000_probe(struct platform_device *pdev)
ndev->dev_addr[i] = ior(db, i+DM9000_PAR);
}

+ if (!is_valid_ether_addr(ndev->dev_addr)) {
+ mac_src = "param";
+ get_mac_addr(ndev, mac_addr);
+ }
+
if (!is_valid_ether_addr(ndev->dev_addr)) {
inv_mac_addr = true;
eth_hw_addr_random(ndev);
--
2.23.0