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@xxxxxxxxxxxxx>
>>
>> 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
