Re: [PATCH v6 00/52] Introduce memory interconnect for NVIDIA Tegra SoCs

[Krzysztof Kozlowski <krzk@kernel.org>]

On Mon, Oct 26, 2020 at 01:16:43AM +0300, Dmitry Osipenko wrote:
> Hello,
> 
> This series brings initial support for memory interconnect to Tegra20,
> Tegra30 and Tegra124 SoCs.
> 
> For the starter only display controllers and devfreq devices are getting
> interconnect API support, others could be supported later on. The display
> controllers have the biggest demand for interconnect API right now because
> dynamic memory frequency scaling can't be done safely without taking into
> account bandwidth requirement from the displays. In particular this series
> fixes distorted display output on T30 Ouya and T124 TK1 devices.

Hi,

You introduced in v6 multiple new patches. Could you describe the
dependencies, if any?

Best regards,
Krzysztof

> Changelog:
> 
> v6: - This series was massively reworked in comparison to v5, most of the
>       patches that previously got r-b need a new round of a review (!).
> 
>     - Added missed clk-rounding to the set() callback of EMC ICC providers.
>       Now clk_set_min_rate() doesn't error out on rate overflow.
> 
>     - Now peak bandwidth is properly taken into account by the set() callback
>       of EMC ICC providers.
> 
>     - EMC runs at 2x of the DRAM bus only on Tegra20, this now taken in account
>       properly by the EMC ICC set() callbacks.
> 
>     - ICC drivers use new icc_sync_state() and xlate_extended().
> 
>     - ICC drivers support new TEGRA_MC_ICC_TAG_ISO for ICC paths, which
>       conveys to ICC driver that memory path uses isochronous transfers.
> 
>     - Added support for memory latency scaling to Tegra30 ICC provider.
>       It's required for fixing display FIFO underflows on T30.
> 
>     - Added basic interconnect support to Tegra124 drivers.
> 
>     - Tegra20/30/124 EMC drivers now support voltage scaling using generic
>       OPP API.
> 
>     - The display bandwidth management is reworked and improved. It now
>       supports both bandwidth and latency allocations. The nv-display is
>       now also taken into account properly, i.e. it's kept untouched.
>       The extra bandwidth reservation required for ISO clients is moved
>       from DC driver to the ICC drivers.
> 
>     - Dropped patch that tuned T20 display controller memory client because
>       turned out that it kills ~30% of memory bandwidth. It should be possible
>       to support client tuning, but it's too complicated for now.
> 
>     - Corrected display's cursor and winb-vfilter ICC clients.
>       The winb-vfilter was erroneously used in place of cursor's client
>       in device-trees.
> 
>     - Added devm_tegra_get_memory_controller() and switched drivers to
>       use it.
> 
>     - Device-tree OPP tables are now supported by memory and devfreq
>       drivers.
> 
>     - Tegra20-devfeq driver is reworked and now uses EMC-stats instead
>       of IMC-stats (which are nearly identical modules) because previously
>       I failed to understand how EMC-stats work and succeeded this time,
>       thinking that it simply doesn't work. This removes a bit icky dependency
>       on using both EMC and MC drivers simultaneously by the devfreq driver.
> 
>     - Tegra20-devfeq driver now is a sub-device of the EMC, it also now uses
>       interconnect API for driving memory bandwidth.
> 
>     - Tegra30-devfreq got interconnect support.
> 
>     - Devfreq patches now use dev_err_probe(), which was suggested by
>       Chanwoo Choi.
> 
>     - Added acks from Chanwoo Choi and Rob Herring to the reviewed and
>       unchanged patches.
> 
>     - Added tested-by from Peter Geis and Nicolas Chauvet, who tested this
>       series on Ouya and TK1 devices, reporting that it fixes display
>       corruption on these devices which happened due to insufficient memory
>       bandwidth.
> 
>     - Added patches to fix T20 EMC registers size.
> 
>     - Fixed missing LA entry for PTC in the Tegra MC drivers.
> 
>     - New and updated patches in v6:
> 
>         dt-bindings: memory: tegra20: emc: Correct registers range in example
>         dt-bindings: memory: tegra20: emc: Document nvidia,memory-controller property
>         dt-bindings: memory: tegra20: emc: Document OPP table and voltage regulator
>         dt-bindings: memory: tegra20: emc: Document mfd-simple compatible and statistics sub-device
>         dt-bindings: memory: tegra30: emc: Document OPP table and voltage regulator
>         dt-bindings: memory: tegra124: mc: Document new interconnect property
>         dt-bindings: memory: tegra124: emc: Document new interconnect property
>         dt-bindings: memory: tegra124: emc: Document OPP table and voltage regulator
>         dt-bindings: tegra30-actmon: Document OPP and interconnect properties
>         dt-bindings: memory: tegra124: Add memory client IDs
>         ARM: tegra: Correct EMC registers size in Tegra20 device-tree
>         ARM: tegra: Add interconnect properties to Tegra124 device-tree
>         ARM: tegra: Add nvidia,memory-controller phandle to Tegra20 EMC device-tree
>         ARM: tegra: Add DVFS properties to Tegra20 EMC device-tree node
>         ARM: tegra: Add DVFS properties to Tegra30 EMC and ACTMON device-tree nodes
>         ARM: tegra: Add DVFS properties to Tegra124 EMC and ACTMON device-tree nodes
>         memory: tegra: Add and use devm_tegra_get_memory_controller()
>         memory: tegra-mc: Add interconnect framework
>         memory: tegra20: Support interconnect framework
>         memory: tegra20-emc: Skip parsing of emc-stats DT sub-node
>         memory: tegra: Add missing latency allowness entry for Page Table Cache
>         memory: tegra: Add FIFO sizes to Tegra30 memory clients
>         memory: tegra30: Support interconnect framework
>         memory: tegra124-emc: Make driver modular
>         memory: tegra124: Support interconnect framework
>         memory: tegra: Remove superfluous error messages around platform_get_irq()
>         drm/tegra: dc: Support memory bandwidth management
>         drm/tegra: dc: Extend debug stats with total number of events
>         PM / devfreq: tegra20: Convert to EMC_STAT driver, support interconnect and device-tree
>         PM / devfreq: tegra30: Support interconnect and OPPs from device-tree
>         PM / devfreq: tegra30: Separate configurations per-SoC generation
>         opp: Put interconnect paths outside of opp_table_lock