On Sat, Jul 11, 2020 at 2:51 PM Yong Wu <yong.wu@xxxxxxxxxxxx> wrote:
>
> In the previous SoC, the M4U HW is in the EMI power domain which is
> always on. the latest M4U is in the display power domain which may be
> turned on/off, thus we have to add pm_runtime interface for it.
>
> we should enable its power before M4U hw initial. and disable it after HW
> initialize.
>
> When the engine work, the engine always enable the power and clocks for
> smi-larb/smi-common, then the M4U's power will always be powered on
> automatically via the device link with smi-common.
>
> Note: we don't enable the M4U power in iommu_map/unmap for tlb flush.
> If its power already is on, of course it is ok. if the power is off,
> the main tlb will be reset while M4U power on, thus the tlb flush while
> m4u power off is unnecessary, just skip it.
>
> Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
> ---
> drivers/iommu/mtk_iommu.c | 54 ++++++++++++++++++++++++++++++++++-----
> 1 file changed, 47 insertions(+), 7 deletions(-)
> ...
> for_each_m4u(data) {
> + /* skip tlb flush when pm is not active */
> + if (pm_runtime_enabled(data->dev) &&
> + !pm_runtime_active(data->dev))
> + continue;
> +
pm_runtime_active(dev) == false implies dev->power.disable_depth == 0,
which implies pm_runtime_enabled(dev) == true, so the
pm_runtime_enabled(data->dev) can be omitted here.
> spin_lock_irqsave(&data->tlb_lock, flags);
> writel_relaxed(F_INVLD_EN1 | F_INVLD_EN0,
> data->base + data->plat_data->inv_sel_reg);
> ...
