Re: [PATCH v5 07/10] PCI/IDE: Add IDE establishment helpers

[<dan.j.williams@intel.com>]

Alexey Kardashevskiy wrote:
[..]
> > +	/*
> > +	 * Now that in use ids are known, grab and assign a free id for idle
> > +	 * streams to remove ambiguity of which key slot is being activated by a
> > +	 * K_SET_GO event (PCIe r7.0 section 6.33.3 IDE Key Management (IDE_KM))
> > +	 */
> > +	reserved_id = find_first_zero_bit(pdev->ide_stream_map, U8_MAX);
> 
> 
> pci_ide_init() is called when PCI is probing and at that point no
> stream is enabled so reserved_id ends up as 0.
> 
> Since my platform only wants 1 stream, should I have called
> pci_ide_init_nr_streams() with "2", not "1"?

Hmm, no I would expect that number only needs to reflect the assignable
id maps.

> pci_ide_stream_alloc() fails to find a stream - fails in:
> 
>   struct stream_index *ep_stream __free(free_stream) = alloc_stream_index(
>           pdev->ide_stream_map, pdev->nr_sel_ide, &__stream[PCI_IDE_EP]);
> 
> as nr_sel_ide==1 (my EP has just one stream). If I go with
> reserved_id==0 and set ide->stream_id=1 in the PSP TSM driver, then
> streamindex#1 gets programmed (which is beyond the end of IDE cap)
> with streamid=0. As if reserved_id is actually reserved_index but the
> device wants me to reserve an ID.

The intent was ID reservation, not index. Will take a look, but first...

> We could simplify it by assigning something like "255" to all
> unused+disabled streams. Thanks,

I thought we were still waiting to to determine if this behavior is a
quirk of a test device, or something that Linux is going to see in
production?

Yes, I want the reserved id to start at 255 (unless BIOS already stole
that id).

In any event I will send out v7 without this, but include it in an
incremental update along with the address association support from
Yilun.