On Mon, 2021-11-22 at 12:44 +0200, Dafna Hirschfeld wrote:
> From: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
>
> In case of v4l2_reqbufs() it is possible, that a TLB flush is done
> without runtime PM being enabled. In that case the "Partial TLB flush
> timed out, falling back to full flush" warning is printed.
>
> Commit c0b57581b73b ("iommu/mediatek: Add power-domain operation")
> introduced has_pm as optimization to avoid checking runtime PM
> when there is no power domain attached. But without the PM domain
> there is still the device driver's runtime PM suspend handler, which
> disables the clock. Thus flushing should also be avoided when there
> is no PM domain involved.
>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
> Reviewed-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
Reviewed-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
> ---
> drivers/iommu/mtk_iommu.c | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 28dc4b95b6d9..b0535fcfd1d7 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -227,16 +227,13 @@ static void
> mtk_iommu_tlb_flush_range_sync(unsigned long iova, size_t size,
> size_t granule,
> struct mtk_iommu_data *data)
> {
> - bool has_pm = !!data->dev->pm_domain;
> unsigned long flags;
> int ret;
> u32 tmp;
>
> for_each_m4u(data) {
> - if (has_pm) {
> - if (pm_runtime_get_if_in_use(data->dev) <= 0)
> - continue;
> - }
> + if (pm_runtime_get_if_in_use(data->dev) <= 0)
> + continue;
>
> spin_lock_irqsave(&data->tlb_lock, flags);
> writel_relaxed(F_INVLD_EN1 | F_INVLD_EN0,
> @@ -261,8 +258,7 @@ static void
> mtk_iommu_tlb_flush_range_sync(unsigned long iova, size_t size,
> writel_relaxed(0, data->base + REG_MMU_CPE_DONE);
> spin_unlock_irqrestore(&data->tlb_lock, flags);
>
> - if (has_pm)
> - pm_runtime_put(data->dev);
> + pm_runtime_put(data->dev);
> }
> }
>
