[PATCH 0/3] Use Tegra's microsecond counter for udelay()

Stephen Warren swarren at wwwdotorg.org
Mon Jun 16 11:52:10 PDT 2014

On 06/12/2014 09:58 AM, Peter De Schrijver wrote:
> This patchset introduces support for Tegra's microsecond counter as the
> udelay() timer. This is useful on Tegra SoCs which do not have an arch timer
> such as Tegra20 and Tegra30. Using the microsecond counter instead of a delay
> based loop avoids potential problems during cpu frequency changes.
> The set consists of 3 patches:
> Patch 1 introduces a new call which is used by the ARM architecture delay
> timer code to prevent changing the delay timer after calibration is finished
> and thus can be in use.
> Patch 2 adds logic to choose the delay timer with the highest resolution. This
> allows the same registration code to be used on all Tegra SoCs and yet use the
> higher resolution arch timer when available (eg on Tegra114 or Tegra124).
> Patch 3 adds the actual delay timer code.
> Patch set has been verified on ventana (Tegra20), beaver (Tegra30),
> dalmore (Tegra114) and jetson TK1 (Tegra124).

I've applied this series to Tegra's for-3.17/delay-timer branch.

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