summaryrefslogtreecommitdiff
path: root/drivers/memory/tegra/tegra20-emc.c
AgeCommit message (Collapse)Author
2020-06-22memory: tegra20-emc: Poll EMC-CaR handshake instead of waiting for interruptDmitry Osipenko
The memory clock-rate change could be running on a non-boot CPU, while the boot CPU handles the EMC interrupt. This introduces an unnecessary latency since boot CPU should handle the interrupt and then notify the sibling CPU about clock-rate change completion. In some rare cases boot CPU could be in uninterruptible state for a significant time (like in a case of KASAN + NFS root), it could get to the point that completion timeouts before boot CPU gets a chance to handle interrupt. The solution is to get rid of the completion and replace it with interrupt-status polling. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2020-06-22memory: tegra: Make debugfs permissions human-readableDmitry Osipenko
Replace the symbolic permissions with octals in order to make them readable. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2020-03-11memory: tegra: Correct debugfs clk rate-range on Tegra20Dmitry Osipenko
Correctly set clk rate-range if number of available timings is zero. This fixes noisy "invalid range [4294967295, 0]" error messages during boot. Fixes: 8209eefa3d37 ("memory: tegra: Implement EMC debugfs interface on Tegra20") Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2020-01-09memory: tegra: Implement EMC debugfs interface on Tegra20Thierry Reding
A common debugfs interface is already available on Tegra124, Tegra186 and Tegra194. Implement the same interface on Tegra20 to enable testing of the EMC frequency scaling code using a unified interface. Signed-off-by: Thierry Reding <treding@nvidia.com>
2019-11-11memory: tegra: Do not handle error from wait_for_completion_timeout()Dmitry Osipenko
Contrary to its wait_for_completion_timeout_interruptible() sibling, the wait_for_completion_timeout() function does not return an error. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2019-11-11memory: tegra: Increase handshake timeout on Tegra20Dmitry Osipenko
Turned out that it could take over a millisecond under some circumstances, like running on a very low CPU/memory frequency. TRM says that handshake happens when there is a "safe" moment, but not explains exactly what that moment is. Apparently at least memory should be idling and thus the low frequency should be a reasonable cause for a longer handshake delay. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2019-11-11memory: tegra: Print a brief info message about EMC timingsDmitry Osipenko
During boot print how many memory timings got the driver and what's the RAM code. This is a very useful information when something is wrong with boards memory timing. Suggested-by: Marc Dietrich <marvin24@gmx.de> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2019-11-11memory: tegra: Pre-configure debug register on Tegra20Dmitry Osipenko
The driver expects certain debug features to be disabled in order to work properly. Let's disable them explicitly for consistency and to not rely on a boot state. Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2019-11-11memory: tegra: Include io.h instead of iopoll.hDmitry Osipenko
The register polling code was gone, but the included header change was missed. Fix it up for consistency. Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2019-11-11memory: tegra: Adapt for Tegra20 clock driver changesDmitry Osipenko
Now Tegra20 and Tegra30 EMC drivers should provide clock-rounding functionality using the new Tegra clock driver API. Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2019-11-11memory: tegra: Don't set EMC rate to maximum on probe for Tegra20Dmitry Osipenko
The memory frequency scaling will be managed by tegra20-devfreq driver and PM QoS once all the prerequisite patches will get upstreamed. The parent clock is now managed by the clock driver and we also should assume that PLLM rate can't be changed on some devices (Galaxy Tab 10.1 for example). Altogether there is no point in touching of clock's rate from the EMC driver. Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2018-11-08memory: tegra: Introduce Tegra20 EMC driverDmitry Osipenko
Introduce driver for the External Memory Controller (EMC) found on Tegra20 chips, which 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. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com> Signed-off-by: Thierry Reding <treding@nvidia.com>