Hi Rob,
On 4/16/19 5:29 PM, Florian Fainelli wrote:
>
>
> On 16/04/2019 13:05, Petr Štetiar wrote:
>> From: John Crispin <john@xxxxxxxxxxx>
>>
>> Many embedded devices have information such as MAC addresses stored
>> inside MTD devices. This patch allows us to add a property inside a node
>> describing a network interface. The new property points at a MTD
>> partition with an offset where the MAC address can be found.
>>
>> This patch has originated in OpenWrt some time ago, so in order to
>> consider usefulness of this patch, here are some real-world numbers
>> which hopefully speak for themselves:
>>
>> * mtd-mac-address used 497 times in 357 device tree files
>> * mtd-mac-address-increment used 74 times in 58 device tree files
>> * mtd-mac-address-increment-byte used 1 time in 1 device tree file
>>
>> Signed-off-by: John Crispin <john@xxxxxxxxxxx>
>> Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
>> [cleanup of the patch for upstream submission]
>> Signed-off-by: Petr Štetiar <ynezz@xxxxxxx>
>> ---
>
> [snip]
>
>> +static const void *of_get_mac_address_mtd(struct device_node *np)
>> +{
>> +#ifdef CONFIG_MTD
>> + void *addr;
>> + size_t retlen;
>> + int size, ret;
>> + u8 mac[ETH_ALEN];
>> + phandle phandle;
>> + const char *part;
>> + const __be32 *list;
>> + struct mtd_info *mtd;
>> + struct property *prop;
>> + u32 mac_inc = 0;
>> + u32 inc_idx = ETH_ALEN-1;
>> + struct device_node *mtd_np = NULL;
>
> Reverse christmas tree would look a bit nicer here.
Do we a variable declaration format preference for drivers/of/*?
-Frank
>
>> +
>> + list = of_get_property(np, "mtd-mac-address", &size);
>> + if (!list || (size != (2 * sizeof(*list))))
>> + return NULL;
>> +
>> + phandle = be32_to_cpup(list++);
>> + if (phandle)
>> + mtd_np = of_find_node_by_phandle(phandle);
>> +
>> + if (!mtd_np)
>> + return NULL;
>> +
>> + part = of_get_property(mtd_np, "label", NULL);
>> + if (!part)
>> + part = mtd_np->name;
>> +
>> + mtd = get_mtd_device_nm(part);
>> + if (IS_ERR(mtd))
>> + return NULL;
>> +
>> + ret = mtd_read(mtd, be32_to_cpup(list), ETH_ALEN, &retlen, mac);
>> + put_mtd_device(mtd);
>> +
>> + of_property_read_u32(np, "mtd-mac-address-increment-byte", &inc_idx);
>
> of_property_read_u8() would probably be good here since this can't be bigger than 5 anyway.
>
>> + if (inc_idx > ETH_ALEN-1)
>> + return NULL; >
>> + if (!of_property_read_u32(np, "mtd-mac-address-increment", &mac_inc))
>> + mac[inc_idx] += mac_inc;
>
> If I use a number greater than and included 128; this will cause a roll over, should this be range checked? Similarly, using of_property_read_u8() might be a better fit?
>
> Other than those, LGTM
