Re: [PATCH v4 00/12] The great interconnecification fixation

[Konrad Dybcio]

+CC Georgi, linux-pm, linux-kernel (thanks git send-email for not including these)

On 14.02.2023 15:37, Konrad Dybcio wrote:
> Hi!
> 
> v3 -> v4 changelog:
> - Drop "Always set QoS params on QNoC", it only causes issues.. this
>   can be investigated another day, as it's not necessary for operation
> 
> - Drop "Add a way to always set QoS registers", same as /\
> 
> - Add a way (and use it) to have no bus_clocks (the ones we set rate on),
>   as at least msm8996 has a bus (A0NoC) that doesn't have any and does
>   all the scaling through RPM requests
> 
> - Promote 8996 icc to core_initcall
> 
> - Introduce keep_alive (see patch [11/12]) (important!, will be used by at least 6375)
> 
> - Allow negative QoS offsets in preparation for introducing 8998 icc [12/12]
> 
> Link to v3: https://lore.kernel.org/linux-arm-msm/20230116132152.405535-1-konrad.dybcio@xxxxxxxxxx/
> 
> v2 -> v3 changelog:
> - Drop "Don't set QoS params before non-zero bw is requested"
> 
> - Rebase on next
> 
> - [1/9] ("..make QoS INVALID default.."): remove unused define for
>   MODE_INVALID_VAL
> 
> - Pick up tags
> 
> v1 -> v2 changelog:
> - reorder "make QoS INVALID default", makes more sense to have it
>   before "Always set QoS params on QNoC"
> 
> - Limit ap_owned-independent QoS setting to QNoC only
> 
> - Add new patches for handling the 8996-and-friends clocks situation
>   and optional BIMC regardless-of-ap_owned QoS programming
> 
> 
> [1] https://lore.kernel.org/linux-arm-msm/14e06574-f95e-8960-0243-8c95a1c294e9@xxxxxxxxxx/T/#m056692bea71d4c272968d5e07afbd9eb07a88123
> [2] https://lore.kernel.org/linux-arm-msm/20230110132202.956619-1-konrad.dybcio@xxxxxxxxxx/
> 
> This series grew quite a bit bigger than the previous [1] attempt, so
> I decided to also add a cover letter.
> 
> Link to v2: [2]
> 
> It addresses a few things that were not quite right:
> 
> - Setting QoS params before a "real" (non-zero) bandwidth request
>   makes little sense (since there's no data supposed to flow through
>   the bus, why would the QoS matter) and (at least newer) downstream
>   prevents that from happening. Do the same in Patch 1.
> 
> - QNoC type buses expect to always have their QoS registers set as long
>   as there's a non-INVALID QoS mode set; ap_owned is not really a thing
>   on these anymore, Patch 3 handles that.
> 
> - The recent MSM8996 boot fix was done quickly and not quite properly,
>   leading to possibly setting the aggregate bus rate on "normal"
>   hardware interface clocks; this series handles that by limiting the
>   number of bus_clocks to 2 (which is the maximum that makes sense,
>   anyway) and handling the rest as "intf_clocks", which are required
>   to access the   hardware at the other end. Patches 5-8 take care of
>   that and Patch 10 reverts the _optional moniker in clk_get_ to make
>   sure we always have the bus scaling clocks, as they're well, kind
>   of important ;)
> 
> - Similarly to QNoC, BIMC on "newer" (which can be loosely approximated
>   by "new enough" == "has only BIMC and QNoC hosts") SoCs expects to
>   always receive QoS programming, whereas BIMC on "older" SoCs cries
>   like a wild boar and crashes the platform when trying to do so
>   unconditionally. Patch 9 adds a way to take care of that for newer
>   SoCs (like SM6375)
> 
> - QoS mode INVALID was assumed by developers before to be the default
>   ("I didn't specify any QoS settings, so the driver can't assume I
>   did.. right? right!?" - wrong, partial struct initialization led to
>   0 being set and 0 corresponded to QoS mode FIXED). Make it so, as
>   that's the logical choice. This allows the "Always set QoS params
>   on QNoC" patch to work without setting tons of what-should-
>   -obviously-be-the-default values everywhere, as well as fixes older
>   drivers that set ap_owned = true but left the QoS mode field unset.
>   Patch 2 cleans that up.
> 
> - Some nodes are physically connected over more than one channel
>   (usually DDR or other high-throughput paths). Patch 4 allows that
>   to be reflected in calculations. This will be required for at least
>   MSM8998 and SM6375 (which will be submitted soon after this lands)
> 
> 
> Konrad Dybcio (12):
>   interconnect: qcom: rpm: make QoS INVALID default, separate out driver
>     data
>   interconnect: qcom: rpm: Add support for specifying channel num
>   interconnect: qcom: Sort kerneldoc entries
>   interconnect: qcom: rpm: Rename icc desc clocks to bus_blocks
>   interconnect: qcom: rpm: Rename icc provider num_clocks to
>     num_bus_clocks
>   interconnect: qcom: rpm: Handle interface clocks
>   interconnect: qcom: icc-rpm: Allow negative num_bus_clocks
>   interconnect: qcom: msm8996: Specify no bus clock scaling on A0NoC
>   interconnect: qcom: rpm: Don't use clk_get_optional for bus clocks
>     anymore
>   interconnect: qcom: msm8996: Promote to core_initcall
>   interconnect: qcom: icc-rpm: Introduce keep_alive
>   interconnect: qcom: icc-rpm: Allow negative QoS offset
> 
>  drivers/interconnect/qcom/icc-rpm.c | 101 ++++++++++++++++++++--------
>  drivers/interconnect/qcom/icc-rpm.h |  41 +++++++----
>  drivers/interconnect/qcom/msm8996.c |  35 ++++++----
>  drivers/interconnect/qcom/sdm660.c  |  16 ++---
>  4 files changed, 126 insertions(+), 67 deletions(-)
>