Messages in this thread | | | Date | Tue, 30 Aug 2022 11:36:55 +0100 | From | "Russell King (Oracle)" <> | Subject | Re: [PATCH v2] ARM: Add sanity check for dev->periphid in amba_probe() |
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On Tue, Aug 30, 2022 at 06:31:14PM +0800, Leizhen (ThunderTown) wrote: > On 2022/8/30 18:07, Russell King (Oracle) wrote: > > For an amba driver, drv->bus will always be pointing at amba_bustype. > > That always has a "match" operation. Therefore, the default of '1' > > above will *never* be used for an AMBA driver. > > > > If drv->bus does not point at amba_bustype, then amba_probe() will > > not be called for "drv". > > > > Therefore, amba_match() must always be called before amba_probe(). > > Oh, I was careless. I think it's drv->match. But the processing flow > will continue to go to "dev->bus->probe". > > __driver_attach(): > ret = driver_match_device(drv, dev); > if (ret == 0) { > /* no match */ > return 0; > } else if (ret == -EPROBE_DEFER) { <------no return in this branch > dev_dbg(dev, "Device match requests probe deferral\n"); > dev->can_match = true; > driver_deferred_probe_add(dev); > } else if (ret < 0) { > dev_dbg(dev, "Bus failed to match device: %d\n", ret); > return ret; > } /* ret > 0 means positive match */ > > ... ... > driver_probe_device(drv, dev); > ...... > dev->bus->probe
And that makes no sense, is an already known issue, and there is a patch to fix it:
https://lore.kernel.org/all/20220817184026.3468620-1-isaacmanjarres@google.com/
-- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
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