linux-kernel - [PATCH v2 11/29] iommu/mediatek: Always pm_runtime

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Message-ID: <20210813065324.29220-12-yong.wu@mediatek.com>
Date:   Fri, 13 Aug 2021 14:53:06 +0800
From:   Yong Wu <yong.wu@...iatek.com>
To:     Joerg Roedel <joro@...tes.org>, Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>
CC:     Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Evan Green <evgreen@...omium.org>,
        Tomasz Figa <tfiga@...gle.com>,
        Tomasz Figa <tfiga@...omium.org>,
        <linux-mediatek@...ts.infradead.org>,
        <srv_heupstream@...iatek.com>, <devicetree@...r.kernel.org>,
        <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>, <chao.hao@...iatek.com>
Subject: [PATCH v2 11/29] iommu/mediatek: Always pm_runtime_get while tlb flush

Prepare for 2 HWs that sharing pgtable in different power-domains.

The previous SoC don't have PM. Only mt8192 has power-domain,
and it is display's power-domain which nearly always is enabled.

When there are 2 M4U HWs, it may has problem.
In this function, we get the pm_status via the m4u dev, but it don't
reflect the real power-domain status of the HW since there may be other
HW also use that power-domain.

Currently we could not get the real power-domain status, thus always
pm_runtime_get here.

Prepare for mt8195, thus, no need fix tags here.

This patch may drop the performance, we expect the user could
pm_runtime_get_sync before dma_alloc_attrs which need tlb ops.

Signed-off-by: Yong Wu <yong.wu@...iatek.com>
---
 drivers/iommu/mtk_iommu.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index add23a36a5e2..abc721a1da21 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -238,8 +238,11 @@ static void mtk_iommu_tlb_flush_range_sync(unsigned long iova, size_t size,
 
 	for_each_m4u(data, head) {
 		if (has_pm) {
-			if (pm_runtime_get_if_in_use(data->dev) <= 0)
+			ret = pm_runtime_resume_and_get(data->dev);
+			if (ret < 0) {
+				dev_err(data->dev, "tlb flush: pm get fail %d.\n", ret);
 				continue;
+			}
 		}
 
 		spin_lock_irqsave(&data->tlb_lock, flags);
-- 
2.18.0