Messages in this thread | | | Subject | Re: [PATCH v2 1/2] EDAC: add EDAC driver for DMC520 | From | James Morse <> | Date | Mon, 25 Mar 2019 18:27:52 +0000 |
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Hi guys,
On 23/03/2019 09:23, Borislav Petkov wrote: > On Thu, Mar 07, 2019 at 01:24:01AM +0000, Rui Zhao wrote: >> From: Rui Zhao <ruizhao@microsoft.com> >> >> New driver supports error detection and correction on >> the devices with ARM DMC-520 memory controller.
A question/suggestion on the direction...
Could we avoid probing the driver based on the root hardware compatible? Could we use the device/chip/platform specific one instead?
We want to avoid per-function edac drivers. If ${my_chip} has edac support for L3 and memory, I should have a ${my_chip}_edac driver that pulls in the appropriate L3 and memory code, and presents a sensible view to edac_core.
Thinking out loud...
You have:
>> +static const struct of_device_id dmc520_edac_driver_id[] = { >> + { .compatible = "arm,dmc-520", }, >> + { /* end of table */ } >> +}; >> +
If you wanted to add another device with edac support, we'd ask you to create ${your_chip}_edac driver and pull in the DMC520 and the other device.
But probing the 'arm,dmc-520' compatible like this leaves us in a tricky place if someone else does this: ${their_device} probes the dmc520 like this too, but they can't stop it on their platform as it will break yours...
It's normal to have a specific compatible, vexpress has: | compatible = "arm,vexpress,v2f-2xv6,ca7x3", "arm,vexpress,v2f-2xv6", "arm,vexpress";
Could we do the same here: | compatible = "vendor,soc-name-dmc520", "arm,dmc-520";
or even: | compatible = "microsoft,product-name-dmc520", "arm,dmc-520"; if there is some firmware/board configuration that means vendor/soc isn't precise enough.
Then we always probe the driver from "vendor,soc-name-dmc520", never from "arm,dmc520".
This means we grow a list of vendor/soc-name that are using this driver, but if one of them wants to support a second edac device, we can remove their vendor/soc-name from the list without affecting anyone else.
Thanks,
James
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