linux-kernel - [PATCH v2 3/5] iommu/mediatek: Remove the power status checking in tlb flush all

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Message-Id: <20211208120744.2415-4-dafna.hirschfeld@collabora.com>
Date:   Wed,  8 Dec 2021 14:07:42 +0200
From:   Dafna Hirschfeld <dafna.hirschfeld@...labora.com>
To:     iommu@...ts.linux-foundation.org, Yong Wu <yong.wu@...iatek.com>,
        Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        linux-mediatek@...ts.infradead.org (moderated list:MEDIATEK IOMMU
        DRIVER),
        linux-arm-kernel@...ts.infradead.org (moderated list:ARM/Mediatek SoC
        support), linux-kernel@...r.kernel.org (open list),
        dafna.hirschfeld@...labora.com, kernel@...labora.com,
        linux-media@...r.kernel.org, sebastian.reichel@...labora.com
Subject: [PATCH v2 3/5] iommu/mediatek: Remove the power status checking in tlb flush all

From: Yong Wu <yong.wu@...iatek.com>

To simplify the code, Remove the power status checking in the
tlb_flush_all, remove this:
   if (pm_runtime_get_if_in_use(data->dev) <= 0)
	    continue;

The mtk_iommu_tlb_flush_all is called from
a) isr
b) tlb flush range fail case
c) iommu_create_device_direct_mappings

In first two cases, the power and clock are always enabled.
In the third case tlb flush is unnecessary because in a later patch
in the series a full flush from the pm_runtime_resume callback is added.

In addition, writing the tlb control register when the iommu is not resumed
is ok and the write is ignored.

Signed-off-by: Yong Wu <yong.wu@...iatek.com>
[refactor commit log]
Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@...labora.com>
---
 drivers/iommu/mtk_iommu.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index dd2c08c54df4..e30ac68fab48 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -210,15 +210,10 @@ static struct mtk_iommu_domain *to_mtk_domain(struct iommu_domain *dom)
 
 static void mtk_iommu_tlb_flush_all(struct mtk_iommu_data *data)
 {
-	if (pm_runtime_get_if_in_use(data->dev) <= 0)
-		return;
-
 	writel_relaxed(F_INVLD_EN1 | F_INVLD_EN0,
 		       data->base + data->plat_data->inv_sel_reg);
 	writel_relaxed(F_ALL_INVLD, data->base + REG_MMU_INVALIDATE);
 	wmb(); /* Make sure the tlb flush all done */
-
-	pm_runtime_put(data->dev);
 }
 
 static void mtk_iommu_tlb_flush_range_sync(unsigned long iova, size_t size,
-- 
2.17.1