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SubjectRe: [PATCH v2 2/3] net: add support for nvmem to eth_platform_get_mac_address()
2018-07-19 14:37 GMT+02:00 Dan Carpenter <dan.carpenter@oracle.com>:
> On Thu, Jul 19, 2018 at 12:06:51PM +0200, Bartosz Golaszewski wrote:
>> It looks simpler as long as you don't add all the new routines
>> resulting from this approach. I've just tried to quickly implement
>> this solution and it resulted in much bigger and duplicated code
>> (checking the validity of mac_addr, copying it etc.). I would prefer
>> the current approach and would like to read someone else's opinion on
>> that.
>
> It's not too bad. There is two extra ether_addr_copy() calls and one
> extra is_valid_ether_addr(). There are two extra alen declarations and
> one extra addr declaration. The functions don't share *that* much code.
>
> regards,
> dan carpenter
>
> diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
> index fd8faa0dfa61..8ab7289a5069 100644
> --- a/net/ethernet/eth.c
> +++ b/net/ethernet/eth.c
> @@ -54,6 +54,8 @@
> #include <linux/if_ether.h>
> #include <linux/of_net.h>
> #include <linux/pci.h>
> +#include <linux/nvmem-consumer.h>
> +#include <linux/mtd/mtd.h>
> #include <net/dst.h>
> #include <net/arp.h>
> #include <net/sock.h>
> @@ -525,7 +527,7 @@ unsigned char * __weak arch_get_platform_mac_address(void)
> return NULL;
> }
>
> -int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
> +static int of_eth_get_mac_address(struct device *dev, u8 *mac_addr)
> {
> const unsigned char *addr;
> struct device_node *dp;
> @@ -547,4 +549,82 @@ int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
> ether_addr_copy(mac_addr, addr);
> return 0;
> }
> +
> +static int nvmem_eth_get_mac_address(struct device *dev, u8 *mac_addr)
> +{
> + struct nvmem_cell *nvmem;
> + unsigned char *addr;
> + size_t alen;
> + int ret = 0;
> +
> + nvmem = nvmem_cell_get(dev, "mac-address");
> + if (PTR_ERR(nvmem) == -EPROBE_DEFER)
> + /* We may have a lookup registered for MAC address but the
> + * corresponding nvmem provider hasn't been registered yet.
> + */
> + return -EPROBE_DEFER;
> + if (IS_ERR(nvmem))
> + return PTR_ERR(nvmem);
> + addr = nvmem_cell_read(nvmem, &alen);
> + if (IS_ERR(addr)) {
> + ret = PTR_ERR(addr);
> + goto put_nvmem;
> + }
> + if (alen != ETH_ALEN || !is_valid_ether_addr(addr)) {
> + ret = -EINVAL;
> + goto free_addr;
> + }
> + ether_addr_copy(mac_addr, addr);
> +free_addr:
> + kfree(addr);
> +put_nvmem:
> + nvmem_cell_put(nvmem);
> + return ret;
> +}
> +
> +static int mtd_eth_get_mac_address(struct device *dev, u8 *mac_addr)
> +{
> + struct mtd_info *mtd;
> + u8 addrbuf[ETH_ALEN];
> + size_t alen;
> + int ret;
> +
> + /* This function should go away as soon as MTD gets nvmem support. */
> + if (!IS_ENABLED(CONFIG_MTD))
> + return -ENODEV;
> +
> + mtd = get_mtd_device_nm("MAC-Address");
> + if (IS_ERR(mtd))
> + return PTR_ERR(mtd);
> + ret = mtd_read(mtd, 0, ETH_ALEN, &alen, addrbuf);
> + if (ret)
> + goto put_mtd;
> + if (!is_valid_ether_addr(addrbuf)) {
> + ret = -EINVAL;
> + goto put_mtd;
> + }
> + ether_addr_copy(mac_addr, addrbuf);
> +put_mtd:
> + put_mtd_device(mtd);
> + return ret;
> +}
> +
> +int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
> +{
> + int ret;
> +
> + ret = of_eth_get_mac_address(dev, mac_addr);
> + if (!ret)
> + return 0;
> + ret = nvmem_eth_get_mac_address(dev, mac_addr);
> + if (ret == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> + if (!ret)
> + return 0;
> + ret = mtd_eth_get_mac_address(dev, mac_addr);
> + if (!ret)
> + return 0;
> +
> + return -ENODEV;
> +}
> EXPORT_SYMBOL(eth_platform_get_mac_address);

Please take a look at v3 - I did it a bit differently but the idea is the same.

Bart

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