On 4/12/2023 1:09 AM, Krzysztof Kozlowski wrote:
On 11/04/2023 18:59, Jim Quinlan wrote:
Regarding "brcm,enable-l1ss":
The Broadcom STB/CM PCIe HW -- a core that is also used by RPi SOCs --
requires the driver probe() to deliberately place the HW one of three
CLKREQ# modes:
(a) CLKREQ# driven by the RC unconditionally
(b) CLKREQ# driven by the EP for ASPM L0s, L1
(c) Bidirectional CLKREQ#, as used for L1 Substates (L1SS).
The HW+driver can tell the difference between downstream devices that
need (a) and (b), but does not know when to configure (c). Further, the
HW may cause a CPU abort on boot if guesses wrong regarding the need for
(c). So we introduce the boolean "brcm,enable-l1ss" property to indicate
that (c) is desired. Setting this property only makes sense when the
downstream device is L1SS-capable and the OS is configured to activate
this mode (e.g. policy==superpowersave).
This property is already present in the Raspian version of Linux, but the
upstream driver implementaion that will follow adds more details and
typo, implementation
discerns between (a) and (b).
Regarding "brcm,completion-timeout-us"
Our HW will cause a CPU abort if the L1SS exit time is longer than the
PCIe transaction completion abort timeout. We've been asked to make this
configurable, so we are introducing "brcm,completion-timeout-us".
Signed-off-by: Jim Quinlan <jim2101024@xxxxxxxxx>
What happened here? Where is the changelog?
It is in the cover letter:
https://lore.kernel.org/all/20230411165919.23955-1-jim2101024@xxxxxxxxx/
but it does not look like the cover letter was copied to you or Rob.
--
Florian
