Messages in this thread | | | Date | Mon, 7 Aug 2023 11:05:48 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH v8 6/8] nvmem: core: Rework layouts to become platform devices |
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On Mon, Aug 07, 2023 at 10:24:17AM +0200, Miquel Raynal wrote: > Current layout support was initially written without modules support in > mind. When the requirement for module support rose, the existing base > was improved to adopt modularization support, but kind of a design flaw > was introduced. With the existing implementation, when a storage device > registers into NVMEM, the core tries to hook a layout (if any) and > populates its cells immediately. This means, if the hardware description > expects a layout to be hooked up, but no driver was provided for that, > the storage medium will fail to probe and try later from > scratch. Technically, the layouts are more like a "plus" and, even we > consider that the hardware description shall be correct, we could still > probe the storage device (especially if it contains the rootfs). > > One way to overcome this situation is to consider the layouts as > devices, and leverage the existing notifier mechanism. When a new NVMEM > device is registered, we can: > - populate its nvmem-layout child, if any > - try to modprobe the relevant driver, if relevant > - try to hook the NVMEM device with a layout in the notifier > And when a new layout is registered: > - try to hook all the existing NVMEM devices which are not yet hooked to > a layout with the new layout > This way, there is no strong order to enforce, any NVMEM device creation > or NVMEM layout driver insertion will be observed as a new event which > may lead to the creation of additional cells, without disturbing the > probes with costly (and sometimes endless) deferrals.
This is good, but why are you using a platform device here? Is it a real platform device, or just a "fake" one you created? If a fake one, please don't do that, use a real device, or a virtual device. Platform devices should ONLY represent actual, real, platform devices (i.e. ones descibed by the firmware).
Sorry but I couldn't answer this question by looking at this patch, the device creation path isn't exactly obvious :)
thanks,
greg k-h
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