linux-kernel - [PATCH v5 7/7] iommu/mediatek: Reduce the tlb flush timeout value

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Message-ID: <1572850868-22315-8-git-send-email-yong.wu@mediatek.com>
Date:   Mon, 4 Nov 2019 15:01:08 +0800
From:   Yong Wu <yong.wu@...iatek.com>
To:     Matthias Brugger <matthias.bgg@...il.com>,
        Joerg Roedel <joro@...tes.org>,
        Will Deacon <will.deacon@....com>
CC:     Evan Green <evgreen@...omium.org>,
        Robin Murphy <robin.murphy@....com>,
        Tomasz Figa <tfiga@...gle.com>,
        <linux-mediatek@...ts.infradead.org>,
        <srv_heupstream@...iatek.com>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <iommu@...ts.linux-foundation.org>, <yong.wu@...iatek.com>,
        <youlin.pei@...iatek.com>, Nicolas Boichat <drinkcat@...omium.org>,
        <anan.sun@...iatek.com>, <cui.zhang@...iatek.com>,
        <chao.hao@...iatek.com>, <edison.hsieh@...iatek.com>
Subject: [PATCH v5 7/7] iommu/mediatek: Reduce the tlb flush timeout value

Reduce the tlb timeout value from 100000us to 1000us. The original value
would make the kernel stuck for 100 ms with interrupts disabled, which
could have other side effects. The flush is expected to always take much
less than 1 ms, so use that instead.

Signed-off-by: Yong Wu <yong.wu@...iatek.com>
---
 drivers/iommu/mtk_iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index c2b7ed5..8ca2e99 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -192,7 +192,7 @@ static void mtk_iommu_tlb_flush_range_sync(unsigned long iova, size_t size,
 
 		/* tlb sync */
 		ret = readl_poll_timeout_atomic(data->base + REG_MMU_CPE_DONE,
-						tmp, tmp != 0, 10, 100000);
+						tmp, tmp != 0, 10, 1000);
 		if (ret) {
 			dev_warn(data->dev,
 				 "Partial TLB flush timed out, falling back to full flush\n");
-- 
1.9.1