Re: [PATCH 2/9] dt-bindings: ata: Convert fsl,pq-sata binding to YAML

J. Neuschäfer
2025-01-31T12:23:13Z

On Mon, Jan 27, 2025 at 08:22:55AM +0900, Damien Le Moal wrote:
> On 1/27/25 03:58, J. Neuschäfer via B4 Relay wrote:
> > From: "J. Neuschäfer" <j.ne@posteo.net>
> >
> > Convert the Freescale PowerQUICC SATA controller binding from text form
> > to YAML. The list of compatible strings reflects current usage.
> >
> > Signed-off-by: J. Neuschäfer <j.ne@posteo.net>
> > ---
> > .../devicetree/bindings/ata/fsl,pq-sata.yaml | 59 ++++++++++++++++++++++
[...]
> > +description: |
> > + SATA nodes are defined to describe on-chip Serial ATA controllers.
> > + Each SATA port should have its own node.
>
> Very unclear. The SATA nodes define ports or controllers ? Normally, a single
> controller can have multiple ports, so the distinction is important.

I'll change it to "Each SATA controller ...", see below.

> > + cell-index:
> > + $ref: /schemas/types.yaml#/definitions/uint32
> > + enum: [1, 2, 3, 4]
> > + description: |
> > + 1 for controller @ 0x18000
> > + 2 for controller @ 0x19000
> > + 3 for controller @ 0x1a000
> > + 4 for controller @ 0x1b000
>
> Are you sure these are different controllers ? Are they not different ports of
> the same controller ? Given that the previous text description define this as
> "controller index", I suspect these are the port offsets and you SATA nodes
> define ports, and not controllers.

They have no shared registers, and each instance has the same register
set (at a different base address).

The MPC8315E reference manual (for example) documents them as:

SATA 1 Controller—Block Base Address 0x1_8000
SATA 2 Controller—Block Base Address 0x1_9000

(table A.24 Serial ATA (SATA) Controller)

Section 15.2 Command Operation implies that each SATA controller
supports a single port:

The SATA controller maintains a queue consisting of up to 16
commands. These commands can be distributed to a single attached
device or, if the system contains a port multiplier, over each
of the attached devices.

So, in conclusion, I'm fairly sure "controller" is the right description.

Best regards,
J. Neuschäfer