Hello,
This series brings initial support for memory interconnect to Tegra20 and Tegra30 SoCs.
For the starter only display controllers 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.
Changelog:
v5: - The devfreq drivers now won't probe if memory timings aren't specified in a device-tree, like was suggested by Chanwoo Choi in a review comment to v4. Initially I wanted to always probe the driver even with a single fixed memory freq, but after a closer look turned out it can't be done easily for Tegra20 driver.
- The "interconnect: Relax requirement in of_icc_get_from_provider()" patch was already applied, hence one less patch in comparison to v4.
- Renamed display interconnect paths in accordance to the names that were used by Thierry Reding in one of his recent patches that supposed to update the Host1x's DT binding.
- Added acks from Chanwoo Choi.
- Added clarifying comment to tegra_mc_icc_set() about why it's a dummy function, this is done in a response to the review comment made by Georgi Djakov to v4.
v4: - All drivers that use interconnect API now select it in the Kconfig in order to properly express the build dependency.
- The IS_ENABLED(CONFIG_INTERCONNECT) is dropped now from all patches.
- Added MODULE_AUTHOR() to the modularized drivers, for completeness.
- Added missed TEGRA_MC Kconfig dependency for the Tegra20 EMC driver.
- Added more acks from Rob Herring that I accidentally missed to add in v3.
v3: - Added acks from Rob Herring that were given to some of the v2 patches.
- Specified name of the TRM documentation chapter in the patch "dt-bindings: host1x: Document new interconnect properties", which was suggested by Rob Herring in the review comment to v2.
- Added patches that allow EMC drivers to be compiled as a loadable kernel modules. This came up during of the v2 review when Georgi Djakov pointed out that interconnect-core could be compiled as a kernel module. Please note that the Tegra124 EMC driver is compile-tested only, I don't have Tegra124 HW.
- In the review comment to [1] Stephen Boyd suggested that it will be better not to make changes to clk API, which was needed in order to avoid clashing of the interconnect driver with the devfreq in regards to memory clk-rate rounding.
[1] https://patchwork.ozlabs.org/project/linux-tegra/patch/20200330231617.17079-...
Stephen Boyd suggested that instead we should provide OPP table via DT. I tried to investigate whether this could be done and turned out it's a bit complicated. Technically it should be doable, but:
1. For now we don't fully support voltage scaling of the CORE regulator and so OPP table in the DT isn't really needed today. We can generate table from the memory timings, which is what Tegra devfreq drivers already do.
2. The OPP table should be defined in the DT for the Memory Controller node and then its usage somehow should be shared by both interconnect and devfreq drivers. It's not obvious what's the best way to do it.
So, it will be much better to postpone the DT OPP table addition until these questions are resolved. We can infer OPPs from the memory timings and we could get the memory rates from the memory driver directly, avoiding the problems induced by the clk API usage. This idea is implemented in v3, see these patches:
PM / devfreq: tegra20: Use MC timings for building OPP table PM / devfreq: tegra30: Use MC timings for building OPP table
v2: - Instead of a single dma-mem interconnect path, the paths are now defined per memory client.
- The EMC provider now uses #interconnect-cells=<0>.
- Dropped Tegra124 because there is no enough information about how to properly calculate required EMC clock rate for it and I don't have hardware for testing. Somebody else will have to work on it.
- Moved interconnect providers code into drivers/memory/tegra/*.
- Added "Create tegra20-devfreq device" patch because interconnect is not very usable without the devfreq memory auto-scaling since memory freq will be fixed to the display's requirement.
Dmitry Osipenko (36): clk: Export clk_hw_reparent() clk: tegra: Remove Memory Controller lock clk: tegra: Export Tegra20 EMC kernel symbols memory: tegra20-emc: Make driver modular memory: tegra30-emc: Make driver modular memory: tegra124-emc: Make driver modular memory: tegra124-emc: Use devm_platform_ioremap_resource soc/tegra: fuse: Export tegra_read_ram_code() memory: tegra20-emc: Initialize MC timings PM / devfreq: tegra20: Silence deferred probe error PM / devfreq: tegra30: Silence deferred probe error PM / devfreq: tegra20: Use MC timings for building OPP table PM / devfreq: tegra30: Use MC timings for building OPP table PM / devfreq: tegra20: Add error messages to tegra_devfreq_target() PM / devfreq: tegra30: Add error messages to tegra_devfreq_target() PM / devfreq: tegra20: Adjust clocks conversion ratio and polling interval PM / devfreq: tegra20: Relax Kconfig dependency dt-bindings: memory: tegra20: mc: Document new interconnect property dt-bindings: memory: tegra20: emc: Document new interconnect property dt-bindings: memory: tegra30: mc: Document new interconnect property dt-bindings: memory: tegra30: emc: Document new interconnect property dt-bindings: host1x: Document new interconnect properties dt-bindings: memory: tegra20: Add memory client IDs dt-bindings: memory: tegra30: Add memory client IDs ARM: tegra: Add interconnect properties to Tegra20 device-tree ARM: tegra: Add interconnect properties to Tegra30 device-tree memory: tegra-mc: Register as interconnect provider memory: tegra20-emc: Use devm_platform_ioremap_resource memory: tegra20-emc: Continue probing if timings are missing in device-tree memory: tegra20-emc: Register as interconnect provider memory: tegra20-emc: Create tegra20-devfreq device memory: tegra30-emc: Continue probing if timings are missing in device-tree memory: tegra30-emc: Register as interconnect provider drm/tegra: dc: Support memory bandwidth management drm/tegra: dc: Tune up high priority request controls for Tegra20 drm/tegra: dc: Extend debug stats with total number of events
.../display/tegra/nvidia,tegra20-host1x.txt | 68 +++++ .../memory-controllers/nvidia,tegra20-emc.txt | 2 + .../memory-controllers/nvidia,tegra20-mc.txt | 3 + .../nvidia,tegra30-emc.yaml | 6 + .../memory-controllers/nvidia,tegra30-mc.yaml | 5 + arch/arm/boot/dts/tegra20.dtsi | 22 +- arch/arm/boot/dts/tegra30.dtsi | 23 +- drivers/clk/clk.c | 1 + drivers/clk/tegra/clk-divider.c | 4 +- drivers/clk/tegra/clk-tegra114.c | 6 +- drivers/clk/tegra/clk-tegra124-emc.c | 63 ++-- drivers/clk/tegra/clk-tegra124.c | 8 +- drivers/clk/tegra/clk-tegra20-emc.c | 3 + drivers/clk/tegra/clk-tegra20.c | 3 +- drivers/clk/tegra/clk-tegra30.c | 3 +- drivers/clk/tegra/clk.h | 14 +- drivers/devfreq/Kconfig | 2 +- drivers/devfreq/tegra20-devfreq.c | 50 +-- drivers/devfreq/tegra30-devfreq.c | 110 +++++-- drivers/gpu/drm/tegra/Kconfig | 1 + drivers/gpu/drm/tegra/dc.c | 289 +++++++++++++++++- drivers/gpu/drm/tegra/dc.h | 13 + drivers/gpu/drm/tegra/drm.c | 19 ++ drivers/gpu/drm/tegra/plane.c | 1 + drivers/gpu/drm/tegra/plane.h | 4 +- drivers/memory/tegra/Kconfig | 9 +- drivers/memory/tegra/mc.c | 121 ++++++++ drivers/memory/tegra/mc.h | 8 + drivers/memory/tegra/tegra124-emc.c | 36 ++- drivers/memory/tegra/tegra20-emc.c | 222 ++++++++++++-- drivers/memory/tegra/tegra30-emc.c | 156 ++++++++-- drivers/soc/tegra/fuse/tegra-apbmisc.c | 2 + include/dt-bindings/memory/tegra20-mc.h | 53 ++++ include/dt-bindings/memory/tegra30-mc.h | 67 ++++ include/linux/clk/tegra.h | 11 + include/soc/tegra/emc.h | 16 - include/soc/tegra/mc.h | 3 + 37 files changed, 1228 insertions(+), 199 deletions(-) delete mode 100644 include/soc/tegra/emc.h