Re: [PATCH net-next v4 2/2] of: net: fix of_get_mac_addr_nvmem() for non-platform devices

[Rob Herring <robh+dt@kernel.org>]

On Fri, Apr 16, 2021 at 2:30 AM Michael Walle <michael@walle.cc> wrote:
>
> Am 2021-04-16 05:24, schrieb Benjamin Herrenschmidt:
> > On Mon, 2021-04-12 at 19:47 +0200, Michael Walle wrote:
> >>
> >>  /**
> >>   * of_get_phy_mode - Get phy mode for given device_node
> >> @@ -59,15 +60,39 @@ static int of_get_mac_addr(struct device_node *np,
> >> const char *name, u8 *addr)
> >>  static int of_get_mac_addr_nvmem(struct device_node *np, u8 *addr)
> >>  {
> >>         struct platform_device *pdev = of_find_device_by_node(np);
> >> +       struct nvmem_cell *cell;
> >> +       const void *mac;
> >> +       size_t len;
> >>         int ret;
> >>
> >> -       if (!pdev)
> >> -               return -ENODEV;
> >> +       /* Try lookup by device first, there might be a
> >> nvmem_cell_lookup
> >> +        * associated with a given device.
> >> +        */
> >> +       if (pdev) {
> >> +               ret = nvmem_get_mac_address(&pdev->dev, addr);
> >> +               put_device(&pdev->dev);
> >> +               return ret;
> >> +       }
> >> +
> >
> > This smells like the wrong band aid :)
> >
> > Any struct device can contain an OF node pointer these days.
>
> But not all nodes might have an associated device, see DSA for example.

I believe what Ben is saying and what I said earlier is going from dev
-> OF node is right and OF node -> dev is wrong. If you only have an
OF node, then use an of_* function.

> And as the name suggests of_get_mac_address() operates on a node. So
> if a driver calls of_get_mac_address() it should work on the node. What
> is wrong IMHO, is that the ethernet drivers where the corresponding
> board
> has a nvmem_cell_lookup registered is calling of_get_mac_address(node).
> It should rather call eth_get_mac_address(dev) in the first place.
>
> One would need to figure out if there is an actual device (with an
> assiciated of_node), then call eth_get_mac_address(dev) and if there
> isn't a device call of_get_mac_address(node).

Yes, I think we're all in agreement.

> But I don't know if that is easy to figure out. Well, one could start
> with just the device where nvmem_cell_lookup is used. Then we could
> drop the workaround above.

Start with the ones just passing dev.of_node directly:

$ git grep 'of_get_mac_address(.*of_node)'
drivers/net/ethernet/aeroflex/greth.c:          addr =
of_get_mac_address(ofdev->dev.of_node);
drivers/net/ethernet/altera/altera_tse_main.c:  macaddr =
of_get_mac_address(pdev->dev.of_node);
drivers/net/ethernet/arc/emac_main.c:   mac_addr =
of_get_mac_address(dev->of_node);
drivers/net/ethernet/broadcom/bgmac-bcma.c:             mac =
of_get_mac_address(bgmac->dev->of_node);
drivers/net/ethernet/cavium/octeon/octeon_mgmt.c:       mac =
of_get_mac_address(pdev->dev.of_node);
drivers/net/ethernet/ethoc.c:           mac =
of_get_mac_address(pdev->dev.of_node);
drivers/net/ethernet/ezchip/nps_enet.c: mac_addr =
of_get_mac_address(dev->of_node);
drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c:  mac_addr =
of_get_mac_address(ofdev->dev.of_node);
drivers/net/ethernet/marvell/pxa168_eth.c:              mac_addr =
of_get_mac_address(pdev->dev.of_node);
drivers/net/ethernet/marvell/sky2.c:    iap =
of_get_mac_address(hw->pdev->dev.of_node);
drivers/net/ethernet/mediatek/mtk_eth_soc.c:    mac_addr =
of_get_mac_address(mac->of_node);
drivers/net/ethernet/microchip/lan743x_main.c:  mac_addr =
of_get_mac_address(pdev->dev.of_node);
drivers/net/ethernet/qualcomm/qca_spi.c:        mac =
of_get_mac_address(spi->dev.of_node);
drivers/net/ethernet/qualcomm/qca_uart.c:       mac =
of_get_mac_address(serdev->dev.of_node);
drivers/net/ethernet/wiznet/w5100-spi.c:        const void *mac =
of_get_mac_address(spi->dev.of_node);
drivers/net/ethernet/xilinx/xilinx_axienet_main.c:      mac_addr =
of_get_mac_address(pdev->dev.of_node);
drivers/net/ethernet/xilinx/xilinx_emaclite.c:  mac_address =
of_get_mac_address(ofdev->dev.of_node);
drivers/net/wireless/ralink/rt2x00/rt2x00dev.c: mac_addr =
of_get_mac_address(rt2x00dev->dev->of_node);
drivers/staging/octeon/ethernet.c:              mac =
of_get_mac_address(priv->of_node);
drivers/staging/wfx/main.c:             macaddr =
of_get_mac_address(wdev->dev->of_node);
net/ethernet/eth.c:             addr = of_get_mac_address(dev->of_node);

Then this will find most of the rest:
git grep -W 'of_get_mac_address([a-z]*)'| grep -E '(node|np)'

Rob