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The Tegra EMC scaling support code is not a clock provider, but merely a
clock consumer, and thus does not need to include
<linux/clk-provider.h>.
Fixes: 0bf368c5b2cf ("memory: tegra: Add EMC scaling support code for Tegra210")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Thierry Reding <treding@nvidia.com>
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Derated timings are used to ensure that the memory chips keep operating
correctly at high temperatures. This adds code to support polling of the
chip operating state when high temperatures are measured on the chip and
change the refresh mode accordingly. Under very high temperatures, the
driver will switch to the derated tables to ensure proper operation of
the memory chips.
Signed-off-by: Thierry Reding <treding@nvidia.com>
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This patch includes the sequence for clock tuning and the dynamic
training mechanism for the clock above 800MHz.
And historically there have been different sequences to change the EMC
clock. The sequence to be used is specified in the EMC table.
However, for the currently supported upstreaming platform, only the most
recent sequence is used. So only support that in this patch.
Based on the work of Peter De Schrijver <pdeschrijver@nvidia.com>.
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
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This is the initial patch for Tegra210 EMC frequency scaling. It has the
code to program various aspects of the EMC that are standardized, but it
does not yet include the specific programming sequence needed for clock
scaling.
The driver is designed to support LPDDR4 SDRAM. Devices that use LPDDR4
need to perform training of the RAM before it can be used. Firmware will
perform this training during early boot and pass a table of supported
frequencies to the kernel via device tree.
For the frequencies above 800 MHz, periodic retraining is needed to
compensate for changes in timing. This periodic training will have to be
performed until the frequency drops back to or below 800 MHz.
This driver provides helpers used during this runtime retraining that
will be used by the sequence specific code in a follow-up patch.
Based on work by Peter De Schrijver <pdeschrijver@nvidia.com>.
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
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