From: Sebastian Reichel <sebastian.reichel@collabora.com>
Date: Wed, 8 Dec 2021 14:07:41 +0200
Subject: iommu/mediatek: Always check runtime PM status in tlb flush range
 callback
Git-commit: 4ea794452ae7220bb02ad950d77d86adcbb86b10
Patch-mainline: v5.18-rc1
References: bsc#1205701

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@collabora.com>
Reviewed-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Yong Wu <yong.wu@mediatek.com>
Link: https://lore.kernel.org/r/20211208120744.2415-3-dafna.hirschfeld@collabora.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 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 1356137f91f9..bcf1f5e11fbd 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -225,16 +225,13 @@ 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,
@@ -259,8 +256,7 @@ 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);
 	}
 }