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

Dmitry Osipenko
2020-10-25T22:17:56Z

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.

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

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/20200330231617.17079-3-digetx@gmail.com/

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 (52):
clk: tegra: Export Tegra20 EMC kernel symbols
soc/tegra: fuse: Export tegra_read_ram_code()
dt-bindings: memory: tegra20: emc: Correct registers range in example
dt-bindings: memory: tegra20: emc: Document nvidia,memory-controller
property
dt-bindings: memory: tegra20: mc: Document new interconnect property
dt-bindings: memory: tegra20: emc: Document new interconnect 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: mc: Document new interconnect property
dt-bindings: memory: tegra30: emc: Document new interconnect property
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: host1x: Document new interconnect properties
dt-bindings: memory: tegra20: Add memory client IDs
dt-bindings: memory: tegra30: Add memory client IDs
dt-bindings: memory: tegra124: Add memory client IDs
ARM: tegra: Correct EMC registers size in Tegra20 device-tree
ARM: tegra: Add interconnect properties to Tegra20 device-tree
ARM: tegra: Add interconnect properties to Tegra30 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-emc: Make driver modular
memory: tegra20-emc: Use devm_platform_ioremap_resource()
memory: tegra20-emc: Continue probing if timings are missing in
device-tree
memory: tegra20: Support interconnect framework
memory: tegra20-emc: Don't parse emc-stats node
memory: tegra: Add missing latency allowness entry for Page Table
Cache
memory: tegra: Add FIFO sizes to Tegra30 memory clients
memory: tegra30-emc: Make driver modular
memory: tegra30-emc: Continue probing if timings are missing in
device-tree
memory: tegra30: Support interconnect framework
memory: tegra124-emc: Make driver modular
memory: tegra124-emc: Use devm_platform_ioremap_resource()
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
opp: Put interconnect paths outside of opp_table_lock
PM / devfreq: tegra20: Silence deferred probe error
PM / devfreq: tegra20: Relax Kconfig dependency
PM / devfreq: tegra20: Convert to EMC_STAT driver, support
interconnect and device-tree
PM / devfreq: tegra30: Silence deferred probe error
PM / devfreq: tegra30: Support interconnect and OPPs from device-tree
PM / devfreq: tegra30: Separate configurations per-SoC generation

.../arm/tegra/nvidia,tegra30-actmon.txt | 25 ++
.../display/tegra/nvidia,tegra20-host1x.txt | 68 +++
.../nvidia,tegra124-emc.yaml | 18 +
.../nvidia,tegra124-mc.yaml | 5 +
.../memory-controllers/nvidia,tegra20-emc.txt | 63 ++-
.../memory-controllers/nvidia,tegra20-mc.txt | 3 +
.../nvidia,tegra30-emc.yaml | 18 +
.../memory-controllers/nvidia,tegra30-mc.yaml | 5 +
arch/arm/boot/dts/tegra124-apalis-emc.dtsi | 8 +
.../arm/boot/dts/tegra124-jetson-tk1-emc.dtsi | 8 +
arch/arm/boot/dts/tegra124-nyan-big-emc.dtsi | 10 +
.../boot/dts/tegra124-peripherals-opp.dtsi | 419 ++++++++++++++++++
arch/arm/boot/dts/tegra124.dtsi | 31 ++
.../boot/dts/tegra20-acer-a500-picasso.dts | 12 +
arch/arm/boot/dts/tegra20-colibri.dtsi | 8 +
arch/arm/boot/dts/tegra20-paz00.dts | 10 +
.../arm/boot/dts/tegra20-peripherals-opp.dtsi | 181 ++++++++
arch/arm/boot/dts/tegra20.dtsi | 42 +-
.../tegra30-asus-nexus7-grouper-common.dtsi | 16 +
.../arm/boot/dts/tegra30-peripherals-opp.dtsi | 383 ++++++++++++++++
arch/arm/boot/dts/tegra30.dtsi | 33 +-
drivers/clk/tegra/Makefile | 2 +-
drivers/clk/tegra/clk-tegra124-emc.c | 41 +-
drivers/clk/tegra/clk-tegra124.c | 27 +-
drivers/clk/tegra/clk-tegra20-emc.c | 3 +
drivers/clk/tegra/clk.h | 16 +-
drivers/devfreq/Kconfig | 3 +-
drivers/devfreq/tegra20-devfreq.c | 186 ++++----
drivers/devfreq/tegra30-devfreq.c | 166 ++++---
drivers/gpu/drm/tegra/Kconfig | 1 +
drivers/gpu/drm/tegra/dc.c | 340 ++++++++++++++
drivers/gpu/drm/tegra/dc.h | 11 +
drivers/gpu/drm/tegra/drm.c | 14 +
drivers/gpu/drm/tegra/hub.c | 3 +
drivers/gpu/drm/tegra/plane.c | 122 +++++
drivers/gpu/drm/tegra/plane.h | 15 +
drivers/memory/tegra/Kconfig | 12 +-
drivers/memory/tegra/mc.c | 184 +++++++-
drivers/memory/tegra/mc.h | 20 +
drivers/memory/tegra/tegra114.c | 6 +
drivers/memory/tegra/tegra124-emc.c | 235 ++++++++--
drivers/memory/tegra/tegra124.c | 37 ++
drivers/memory/tegra/tegra20-emc.c | 244 ++++++++--
drivers/memory/tegra/tegra20.c | 34 ++
drivers/memory/tegra/tegra210-emc-core.c | 39 +-
drivers/memory/tegra/tegra30-emc.c | 245 ++++++++--
drivers/memory/tegra/tegra30.c | 191 ++++++++
drivers/opp/core.c | 21 +-
drivers/soc/tegra/fuse/tegra-apbmisc.c | 2 +
include/dt-bindings/memory/tegra124-mc.h | 68 +++
include/dt-bindings/memory/tegra20-mc.h | 53 +++
include/dt-bindings/memory/tegra30-mc.h | 67 +++
include/linux/clk/tegra.h | 9 +
include/soc/tegra/emc.h | 16 -
include/soc/tegra/mc.h | 26 ++
55 files changed, 3477 insertions(+), 348 deletions(-)
create mode 100644 arch/arm/boot/dts/tegra124-peripherals-opp.dtsi
create mode 100644 arch/arm/boot/dts/tegra20-peripherals-opp.dtsi
create mode 100644 arch/arm/boot/dts/tegra30-peripherals-opp.dtsi
delete mode 100644 include/soc/tegra/emc.h

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2.27.0