Re: [PATCH v3 12/23] dt-bindings: ata: ahci: Add platform capability properties

From: Hannes Reinecke
Date: Thu May 12 2022 - 02:58:06 EST


On 5/12/22 01:17, Serge Semin wrote:
In case if the platform doesn't have BIOS or a comprehensive firmware
installed then the HBA capability flags will be left uninitialized. As a
good alternative we can define a set AHCI DT-node properties to describe
all of HW-init capabilities flags. Luckily there aren't too many of them.
SSS - Staggered Spin-up support and MPS - Mechanical Presence Switch
support determine the corresponding feature availability for whole HBA by
means of the "hba-sss" and "hba-smps" properties. Each port can have the
"hba-{hpcp,mpsp,cpd,esp,fbscp}" defined indicatating that the port
supports the next functionality: HPCP - HotPlug capable port, MPSP -
Mechanical Presence Switch attached to a port, CPD - Cold Plug detection,
ESP - External SATA Port (eSATA), FBSCP - FIS-based switching capable
port.

Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>

---

Alternatively we could define them as a bitfield, but having a set of
boolean properties seemed a better idea since in that case we can
implement a simple inter-dependency rules for them, which can't be done
should we take the bitfields path.
---
.../devicetree/bindings/ata/ahci-common.yaml | 66 +++++++++++++++++++
.../bindings/ata/ahci-platform.yaml | 11 ++++
2 files changed, 77 insertions(+)

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
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