On Wed, Jul 18, 2018 at 06:10:34PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
>
> Many non-DT platforms read the MAC address from EEPROM. Usually it's
> either done with callbacks defined in board files or from SoC-specific
> ethernet drivers.
>
> In order to generalize this, try to read the MAC from nvmem in
> eth_platform_get_mac_address() using a standard lookup name:
> "mac-address".
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> ---
> net/ethernet/eth.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
> index 6b64586fd2af..adf5bd03851f 100644
> --- a/net/ethernet/eth.c
> +++ b/net/ethernet/eth.c
> @@ -54,6 +54,7 @@
> #include <linux/if_ether.h>
> #include <linux/of_net.h>
> #include <linux/pci.h>
> +#include <linux/nvmem-consumer.h>
> #include <net/dst.h>
> #include <net/arp.h>
> #include <net/sock.h>
> @@ -530,7 +531,10 @@ int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
> struct device_node *dp = dev_is_pci(dev) ?
> pci_device_to_OF_node(to_pci_dev(dev)) : dev->of_node;
> const unsigned char *addr = NULL;
> + unsigned char addrbuf[ETH_ALEN];
> + struct nvmem_cell *nvmem;
> const char *from = NULL;
> + size_t alen;
>
> if (dp) {
> addr = of_get_mac_address(dp);
> @@ -544,6 +548,31 @@ int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
> from = "arch callback";
> }
>
> + if (!addr) {
> + nvmem = nvmem_cell_get(dev, "mac-address");
> + if (IS_ERR(nvmem) && PTR_ERR(nvmem) == -EPROBE_DEFER)
How does EPROBE_DEFER work here? You say the use case is
Non-DT. Without having DT, how do you know the cell should exist, but
does not yet exist? I might be looking at old code, but i only see
-EPROBE_DEFER inside the if (np) case.
> + /* We may have a lookup registered for MAC address but
> + * the corresponding nvmem provider hasn't been
> + * registered yet.
> + */
> + return -EPROBE_DEFER;
You really should return real errors. If i'm reading
__nvmem_device_get() right, it will return a NULL pointer when the
cell does not exist. NULL is not an error, so IS_ERR() will return
false. So you should return all errors from nvmem_cell_get().
Andrew
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