Date: Sat, 23 Sep 2023 14:56:08 -0500 From: Mike Karels <mike@karels.net> To: Ronald Klop <ronald@FreeBSD.org> Cc: "Patrick M. Hausen" <pmh@hausen.com>, Mark Millard <marklmi@yahoo.com>, freebsd-arm@freebsd.org Subject: Re: Getting a stable MAC address for a RPI CM3+ with ue0 interface Message-ID: <041A6D22-F0AD-4AB9-B2D3-63BF5526E28D@karels.net> In-Reply-To: <FE9F3D43-4C06-47F5-8700-5A2E6A63EF53@karels.net> References: <3C1032FF-B914-4863-8A03-759A8B4BE216@hausen.com> <77E70D30-8E7D-42DC-A041-3A783E1C6908@yahoo.com> <5205C76E-BAB4-4AB7-8A03-1E8A2D4353BB@hausen.com> <B50A4409-84C0-405D-8099-43692243AE52@hausen.com> <84C20AD4-1F37-414E-8808-60A2C9B621D9@karels.net> <4951c134-39be-43de-0aa7-430a136d8b36@FreeBSD.org> <FE9F3D43-4C06-47F5-8700-5A2E6A63EF53@karels.net>
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On 23 Sep 2023, at 14:50, Mike Karels wrote:
> On 23 Sep 2023, at 14:28, Ronald Klop wrote:
>
>> On 9/20/23 22:02, Mike Karels wrote:
>>> On 20 Sep 2023, at 14:49, Patrick M. Hausen wrote:
>>>
>>>> Hi all,
>>>>
>>>> some more research ...
>>>>
>>>>> Am 20.09.2023 um 21:05 schrieb Patrick M. Hausen <pmh@hausen.com>:
>>>>> No worky.
>>>>> [...]
>>>>
>>>>
>>>> I could not find any code in the network startup routines in userland that
>>>> would generate and configure a random MAC address. So I looked for
>>>> the driver.
>>>>
>>>> Apparently the TuringPi uses smsc(4), and there we have it straight from
>>>> the driver source:
>>>>
>>>> -------------------
>>>> static void
>>>> smsc_attach_post(struct usb_ether *ue)
>>>> {
>>>> [...]
>>>> /* Attempt to get the mac address, if an EEPROM is not attached this
>>>> * will just return FF:FF:FF:FF:FF:FF, so in such cases we invent a MAC
>>>> * address based on urandom.
>>>> */
>>>> [...]
>>>> /* Initialise the chip for the first time */
>>>> smsc_chip_init(sc);
>>>> }
>>>> -------------------
>>>>
>>>> So what we would really need is a tunable - one per driver or possibly a
>>>> common one read and acted upon by all of the USB ethernet drivers ...
>>>
>>> There is a routine called ether_gen_addr(), which will generate an
>>> Ethernet MAC based on the hostid and the interface name, both of which
>>> are reasonably stable. Not very many drivers use it though. It
>>> would probably be an improvement.
>>>
>>>> With no code on our side to perform anything, no wonder the RPI
>>>> config files have no effect.
>>>
>>> It would seem wrong to me to have USB Ethernet drivers using an RPI-specific
>>> mechanism.
>>>
>>>> Dang. That's frustrating. With aarch64 having been promoted to "tier 1"
>>>> I really expected full support for all RPI platforms and related features
>>>> and hardware.
>>>>
>>>> Or am I misreading that? I though that the Pi was *the* aarch64 platform,
>>>> at least in numbers ...
>>>
>>> In numbers, probably. In support, no.
>>>
>>> Mike
>>>
>>>> Kind regards,
>>>> Patrick
>>>
>>
>>
>> Would this work?
>>
>> diff --git a/sys/dev/usb/net/if_smsc.c b/sys/dev/usb/net/if_smsc.c
>> index 0a0268bfa1a2..4a7983a20717 100644
>> --- a/sys/dev/usb/net/if_smsc.c
>> +++ b/sys/dev/usb/net/if_smsc.c
>> @@ -1554,6 +1554,7 @@ static void
>> smsc_attach_post(struct usb_ether *ue)
>> {
>> struct smsc_softc *sc = uether_getsc(ue);
>> + struct ether_addr eaddr;
>> uint32_t mac_h, mac_l;
>> int err;
>> @@ -1589,9 +1590,10 @@ smsc_attach_post(struct usb_ether *ue)
>> err = usb_fdt_get_mac_addr(sc->sc_ue.ue_dev, &sc->sc_ue);
>> #endif
>> if ((err != 0) || (!ETHER_IS_VALID(sc->sc_ue.ue_eaddr))) {
>> - read_random(sc->sc_ue.ue_eaddr, ETHER_ADDR_LEN);
>> - sc->sc_ue.ue_eaddr[0] &= ~0x01; /* unicast */
>> - sc->sc_ue.ue_eaddr[0] |= 0x02; /* locally administered */
>> + device_printf(ue->ue_dev, "No MAC address found. Using ether_gen_addr().\n");
>> + ether_gen_addr(ue->ue_ifp, &eaddr);
>> + for (int i = 0; i < ETHER_ADDR_LEN; i++)
>> + sc->sc_ue.ue_eaddr[i] = eaddr.octet[i];
>> }
>> }
>>
>>
>> I don't have the hardware so I can't test it.
>
> It looks right to me, and seems like a big improvement. I don't have the
> hardware either.
Actually, you could pass sc->sc_ue.ue_eaddr as the second parameter to
ether_gen_addr, and eliminate eaddr.
Mike
>
>> Regards,
>> Ronald.
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