Messages in this thread | | | Date | Thu, 21 May 2020 08:07:38 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCH v4 7/7] firmware: smccc: Add ARCH_SOC_ID support |
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On Wed, May 20, 2020 at 11:51:47PM +0200, Arnd Bergmann wrote: > On Mon, May 18, 2020 at 1:55 PM Sudeep Holla <sudeep.holla@arm.com> wrote: > > > > On Mon, May 18, 2020 at 11:30:21AM +0200, Arnd Bergmann wrote: > > > On Mon, May 18, 2020 at 11:12 AM Sudeep Holla <sudeep.holla@arm.com> wrote: > > > > > > > +static ssize_t > > > > +jep106_cont_bank_code_show(struct device *dev, struct device_attribute *attr, > > > > + char *buf) > > > > +{ > > > > + return sprintf(buf, "0x%02x\n", JEP106_BANK_CONT_CODE(soc_id_version)); > > > > +} > > > > + > > > > +static DEVICE_ATTR_RO(jep106_cont_bank_code); > > > > + > > > > +static ssize_t > > > > +jep106_identification_code_show(struct device *dev, > > > > + struct device_attribute *attr, char *buf) > > > > +{ > > > > + return sprintf(buf, "0x%02x\n", JEP106_ID_CODE(soc_id_version)); > > > > +} > > > > > > I think we should try hard to avoid nonstandard attributes for the soc device. > > > > > > > I agree with that in general but this is bit different for below mentioned > > reason. > > > > > Did you run into a problem with finding one of the existing attributes > > > that can be used to hold the fields? > > > > > > > Not really! The 2 JEP106 codes can be used to derive the manufacturer which > > could match one of the existing attributes. However doing so might require > > importing the huge JEP106 list as it needs to be maintained and updated > > in the kernel. Also that approach will have the compatibility issue and > > that is the reason for introducing these attributes representing raw > > values for userspace. > > I was thinking they codes could just be part of the normal strings rather > than get translated. Can you give an example what they would look like > with your current code? >
Sure. Couple of example: Cont Code Identifier Manufacturer 0 0x1 AMD 0 0x0e Freescale (Motorola) 4 0x3b ARM
I initially thought of value like "jep106-0-1" for AMD "jep-4-3b" for ARM,..etc for the standard attribute family or machine. But I was not convinced fully on that approach as it will be deviation from normal values in those attributes. Further this represents the vendor name rather than the family or machine.
> If you think they should be standard attributes, how about adding them > to the default list, and hardcoding them in the other soc device drivers > based on the information we have available there? >
That may be possible, I can take a look at the existing drivers and check if that is feasible(which I think should be). Thanks for that suggestion.
-- Regards, Sudeep
[1] https://github.com/skottler/memtest86/blob/master/jedec_id.h
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