On Tue, Oct 29, 2024 at 4:19 AM Dirk Behme <dirk.behme@xxxxxxxxxxxx> wrote:
>
> On 29.10.2024 09:50, Danilo Krummrich wrote:
> > On Tue, Oct 29, 2024 at 08:20:55AM +0100, Dirk Behme wrote:
> >> On 28.10.2024 11:19, Danilo Krummrich wrote:
> >>> On Thu, Oct 24, 2024 at 11:11:50AM +0200, Dirk Behme wrote:
> >>>>> +/// IdTable type for platform drivers.
> >>>>> +pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<of::DeviceId, T>;
> >>>>> +
> >>>>> +/// The platform driver trait.
> >>>>> +///
> >>>>> +/// # Example
> >>>>> +///
> >>>>> +///```
> >>>>> +/// # use kernel::{bindings, c_str, of, platform};
> >>>>> +///
> >>>>> +/// struct MyDriver;
> >>>>> +///
> >>>>> +/// kernel::of_device_table!(
> >>>>> +/// OF_TABLE,
> >>>>> +/// MODULE_OF_TABLE,
> >>>>
> >>>> It looks to me that OF_TABLE and MODULE_OF_TABLE are quite generic names
> >>>> used here. Shouldn't they be somehow driver specific, e.g. OF_TABLE_MYDRIVER
> >>>> and MODULE_OF_TABLE_MYDRIVER or whatever? Same for the other
> >>>> examples/samples in this patch series. Found that while using the *same*
> >>>> somewhere else ;)
> >>>
> >>> I think the names by themselves are fine. They're local to the module. However,
> >>> we stringify `OF_TABLE` in `module_device_table` to build the export name, i.e.
> >>> "__mod_of__OF_TABLE_device_table". Hence the potential duplicate symbols.
> >>>
> >>> I think we somehow need to build the module name into the symbol name as well.
> >>
> >> Something like this?
> >
> > No, I think we should just encode the Rust module name / path, which should make
> > this a unique symbol name.
> >
> > diff --git a/rust/kernel/device_id.rs b/rust/kernel/device_id.rs
> > index 5b1329fba528..63e81ec2d6fd 100644
> > --- a/rust/kernel/device_id.rs
> > +++ b/rust/kernel/device_id.rs
> > @@ -154,7 +154,7 @@ macro_rules! module_device_table {
> > ($table_type: literal, $module_table_name:ident, $table_name:ident) => {
> > #[rustfmt::skip]
> > #[export_name =
> > - concat!("__mod_", $table_type, "__", stringify!($table_name), "_device_table")
> > + concat!("__mod_", $table_type, "__", module_path!(), "_", stringify!($table_name), "_device_table")
> > ]
> > static $module_table_name: [core::mem::MaybeUninit<u8>; $table_name.raw_ids().size()] =
> > unsafe { core::mem::transmute_copy($table_name.raw_ids()) };
> >
> > For the doctests for instance this
> >
> > "__mod_of__OF_TABLE_device_table"
> >
> > becomes
> >
> > "__mod_of__doctests_kernel_generated_OF_TABLE_device_table".
>
>
> What implies *one* OF/PCI_TABLE per path (file)?
It's generally one per module, but it's one per type because it is one
type per driver. So platform (and most other) drivers can have $bus,
DT, and ACPI tables.
While you could have 1 module with N drivers, I don't think I've ever
seen that case and certainly not something we'd encourage. Perhaps it
is just not possible to disallow in C, but we can in rust? That may be
a benefit, not a limitation.
Rob
