[PATCH v4 00/10] memory: tegra: Introduce Tegra30 EMC driver

Dmitry Osipenko
2019-06-16T23:35:41Z

Hello,

This series introduces driver for the External Memory Controller (EMC)
found on Tegra30 chips, it controls the external DRAM on the board. The
purpose of this driver is to program memory timing for external memory on
the EMC clock rate change. The driver was tested using the ACTMON devfreq
driver that performs memory frequency scaling based on memory-usage load.

Changelog:

v4: - Addressed review comments that were made by Peter De Schrijver to v3
by adding fence_udelay() after writes in the "Add custom EMC clock
implementation" patch.

- Added two new minor patches:

memory: tegra: Ensure timing control debug features are disabled
memory: tegra: Consolidate registers definition into one place

The first one is needed to ensure that EMC driver will work
properly regardless of hardware configuration left after boot.
The second patch is just a minor code cleanup.

- The "Introduce Tegra30 EMC driver" got also few very minor changes.
Now every possible error case is handled, nothing is ignored.
The EMC_DBG register is explicitly initialized during probe to be
on the safe side.

v3: - Addressed review comments that were made by Stephen Boyd to v2 by
adding explicit typing for the callback variable, by including
"clk-provider.h" directly in the code and by dropping __clk_lookup
usage where possible.

- Added more patches into this series:

memory: tegra20-emc: Drop setting EMC rate to max on probe
memory: tegra20-emc: Adapt for clock driver changes
memory: tegra20-emc: Include io.h instead of iopoll.h
memory: tegra20-emc: Replace clk_get_sys with devm_clk_get

Initially I was going to include these patches into other patchset,
but changed my mind after rearranging things a tad. The "Adapt for
clock driver changes" patch is directly related to the clock changes
done in the first patch of this series, the rest are minor cleanups
that are fine to include here as well.

- Added some more words to the commit message of "Add binding for NVIDIA
Tegra30 External Memory Controller" patch, clarifying why common DDR
timing device-tree form isn't suitable for Tegra30.

- The Tegra30 EMC driver now explicitly selects the registers access
mode (EMC_DBG mux), not relying on the setting left from bootloader.

v2: - Added support for changing MC clock diver configuration based on
Memory Controller (MC) configuration which is part of the memory
timing.

- Merged the "Add custom EMC clock implementation" patch into this
series because the "Introduce Tegra30 EMC driver" patch directly
depends on it. Please note that Tegra20 EMC driver will need to be
adapted for the clock changes as well, I'll send out the Tegra20
patches after this series will be applied because of some other
dependencies (devfreq) and because the temporary breakage won't
be critical (driver will just error out on probe).

- EMC driver now performs MC configuration validation by checking
that the number of MC / EMC timings matches and that the timings
rate is the same.

- EMC driver now supports timings that want to change the MC clock
configuration.

- Other minor prettifying changes of the code.

Dmitry Osipenko (10):
clk: tegra20/30: Add custom EMC clock implementation
memory: tegra20-emc: Drop setting EMC rate to max on probe
memory: tegra20-emc: Adapt for clock driver changes
memory: tegra20-emc: Include io.h instead of iopoll.h
memory: tegra20-emc: Replace clk_get_sys with devm_clk_get
dt-bindings: memory: Add binding for NVIDIA Tegra30 External Memory
Controller
memory: tegra: Introduce Tegra30 EMC driver
memory: tegra: Ensure timing control debug features are disabled
memory: tegra: Consolidate registers definition into one place
ARM: dts: tegra30: Add External Memory Controller node

.../memory-controllers/nvidia,tegra30-emc.txt | 249 ++++
arch/arm/boot/dts/tegra30.dtsi | 11 +
drivers/clk/tegra/Makefile | 2 +
drivers/clk/tegra/clk-tegra20-emc.c | 305 +++++
drivers/clk/tegra/clk-tegra20.c | 55 +-
drivers/clk/tegra/clk-tegra30.c | 38 +-
drivers/clk/tegra/clk.h | 6 +
drivers/memory/tegra/Kconfig | 10 +
drivers/memory/tegra/Makefile | 1 +
drivers/memory/tegra/mc.c | 42 +-
drivers/memory/tegra/mc.h | 74 +-
drivers/memory/tegra/tegra124.c | 20 -
drivers/memory/tegra/tegra20-emc.c | 94 +-
drivers/memory/tegra/tegra30-emc.c | 1197 +++++++++++++++++
drivers/memory/tegra/tegra30.c | 24 +
include/linux/clk/tegra.h | 14 +
include/soc/tegra/mc.h | 2 +-
17 files changed, 1973 insertions(+), 171 deletions(-)
create mode 100644 Documentation/devicetree/bindings/memory-controllers/nvidia,tegra30-emc.txt
create mode 100644 drivers/clk/tegra/clk-tegra20-emc.c
create mode 100644 drivers/memory/tegra/tegra30-emc.c

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2.22.0