El vie, 17 mar 2023 a las 17:41, Florian Fainelli (<f.fainelli@xxxxxxxxx>) escribió: > > On 3/17/23 09:23, Álvaro Fernández Rojas wrote: > > El vie, 17 mar 2023 a las 15:29, Vladimir Oltean (<olteanv@xxxxxxxxx>) escribió: > >> > >> On Fri, Mar 17, 2023 at 03:17:12PM +0100, Álvaro Fernández Rojas wrote: > >>>> The proposed solution is too radical for a problem that was not properly > >>>> characterized yet, so this patch set has my temporary NACK. > >>> > >>> Forgive me, but why do you consider this solution too radical? > >> > >> Because it involves changing device tree bindings (stable ABI) in an > >> incompatible way. > >> > >>>> > >>>>> But maybe Florian or Jonas can give some more details about the issue... > >>>> > >>>> I think you also have the tools necessary to investigate this further. > >>>> We need to know what resource belonging to the switch is it that the > >>>> MDIO mux needs. Where is the earliest place you can add the call to > >>>> b53_mmap_mdiomux_init() such that your board works reliably? Note that > >>>> b53_switch_register() indirectly calls b53_setup(). By placing this > >>>> function where you have, the entirety of b53_setup() has finished > >>>> execution, and we don't know exactly what is it from there that is > >>>> needed. > >>> > >>> In the following link you will find different bootlogs related to > >>> different scenarios all of them with the same result: any attempt of > >>> calling b53_mmap_mdiomux_init() earlier than b53_switch_register() > >>> will either result in a kernel panic or a device hang: > >>> https://gist.github.com/Noltari/b0bd6d5211160ac7bf349d998d21e7f7 > >>> > >>> 1. before b53_switch_register(): > >>> > >>> 2. before dsa_register_switch(): > >>> > >>> 3. before b53_switch_init(): > >> > >> Did you read what I said? > > > > Yes, but I didn't get your point, sorry for that. > > > >> > >> | Note that b53_switch_register() indirectly calls b53_setup(). By placing > >> | this function where you have, the entirety of b53_setup() has finished > >> | execution, and we don't know exactly what is it from there that is > >> | needed. > >> > >> Can you place the b53_mmap_mdiomux_init() in various places within > >> b53_setup() to restrict the search further? > > > > I tried and these are the results: > > https://gist.github.com/Noltari/d5bdba66b8f2e392c9e4c2759661d862 > > > > All of them hang when dsa_tree_setup() is called for DSA tree 1 > > (external switch) without having completely setup DSA tree 0 (internal > > switch): > > [ 1.471345] b53-switch 10e00000.switch: found switch: BCM63xx, rev 0 > > [ 1.481099] bcm6368-enetsw 1000d800.ethernet: IRQ tx not found > > [ 1.506752] bcm6368-enetsw 1000d800.ethernet: mtd mac 4c:60:de:86:52:12 > > [ 1.594365] bcm7038-wdt 1000005c.watchdog: Registered BCM7038 Watchdog > > [ 1.612008] NET: Registered PF_INET6 protocol family > > [ 1.645617] Segment Routing with IPv6 > > [ 1.649547] In-situ OAM (IOAM) with IPv6 > > [ 1.653948] NET: Registered PF_PACKET protocol family > > [ 1.659984] 8021q: 802.1Q VLAN Support v1.8 > > [ 1.699193] b53-switch 10e00000.switch: found switch: BCM63xx, rev 0 > > [ 2.124257] bcm53xx 0.1:1e: found switch: BCM53125, rev 4 > > *** Device hang *** > > > > I don't know if there's a way to defer the probe of DSA tree 1 (the > > external switch) until DSA tree 0 (the internal switch) is completely > > setup, because that would probably be the only alternative way of > > fixing this. > > Could you find out which part is hanging? It looks like there is a busy > waiting operation that we never complete? I don't think so, but I will try to debug the exact issue and report back. > > DSA should be perfectly capable of dealing with disjoint trees being > cascaded to one another, as this is entirely within how the framework is > designed. > > What I suspect might be happening is a "double programming" effect, > similar or identical to what was described in this commit: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b8c6cd1d316f3b01ae578d8e29179f6396c0eaa2 Thanks for the info, I will look into this. > > using the MDIO mux would properly isolate the pseudo PHYs of the switch > such that a given MDIO write does not end up programming *both* the > internal and external switches. It could also be a completely different > problem. > -- > Florian >
