linux-kernel - [PATCH v5 6/7] iommu/mediatek: Get rid of the pgtlock

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Date:   Mon, 4 Nov 2019 15:01:07 +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 6/7] iommu/mediatek: Get rid of the pgtlock

Now we have tlb_lock for the HW tlb flush, then pgtable code hasn't
needed the external "pgtlock" for a while. this patch remove the
"pgtlock".

Signed-off-by: Yong Wu <yong.wu@...iatek.com>
---
 drivers/iommu/mtk_iommu.c | 25 +++----------------------
 1 file changed, 3 insertions(+), 22 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 0e5f41f..c2b7ed5 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -101,8 +101,6 @@
 #define MTK_M4U_TO_PORT(id)		((id) & 0x1f)
 
 struct mtk_iommu_domain {
-	spinlock_t			pgtlock; /* lock for page table */
-
 	struct io_pgtable_cfg		cfg;
 	struct io_pgtable_ops		*iop;
 
@@ -295,8 +293,6 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom)
 {
 	struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
 
-	spin_lock_init(&dom->pgtlock);
-
 	dom->cfg = (struct io_pgtable_cfg) {
 		.quirks = IO_PGTABLE_QUIRK_ARM_NS |
 			IO_PGTABLE_QUIRK_NO_PERMS |
@@ -395,18 +391,13 @@ static int mtk_iommu_map(struct iommu_domain *domain, unsigned long iova,
 {
 	struct mtk_iommu_domain *dom = to_mtk_domain(domain);
 	struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
-	unsigned long flags;
-	int ret;
 
 	/* The "4GB mode" M4U physically can not use the lower remap of Dram. */
 	if (data->enable_4GB)
 		paddr |= BIT_ULL(32);
 
-	spin_lock_irqsave(&dom->pgtlock, flags);
-	ret = dom->iop->map(dom->iop, iova, paddr, size, prot);
-	spin_unlock_irqrestore(&dom->pgtlock, flags);
-
-	return ret;
+	/* Synchronize with the tlb_lock */
+	return dom->iop->map(dom->iop, iova, paddr, size, prot);
 }
 
 static size_t mtk_iommu_unmap(struct iommu_domain *domain,
@@ -414,14 +405,8 @@ static size_t mtk_iommu_unmap(struct iommu_domain *domain,
 			      struct iommu_iotlb_gather *gather)
 {
 	struct mtk_iommu_domain *dom = to_mtk_domain(domain);
-	unsigned long flags;
-	size_t unmapsz;
-
-	spin_lock_irqsave(&dom->pgtlock, flags);
-	unmapsz = dom->iop->unmap(dom->iop, iova, size, gather);
-	spin_unlock_irqrestore(&dom->pgtlock, flags);
 
-	return unmapsz;
+	return dom->iop->unmap(dom->iop, iova, size, gather);
 }
 
 static void mtk_iommu_flush_iotlb_all(struct iommu_domain *domain)
@@ -447,13 +432,9 @@ static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
 {
 	struct mtk_iommu_domain *dom = to_mtk_domain(domain);
 	struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
-	unsigned long flags;
 	phys_addr_t pa;
 
-	spin_lock_irqsave(&dom->pgtlock, flags);
 	pa = dom->iop->iova_to_phys(dom->iop, iova);
-	spin_unlock_irqrestore(&dom->pgtlock, flags);
-
 	if (data->enable_4GB && pa >= MTK_IOMMU_4GB_MODE_REMAP_BASE)
 		pa &= ~BIT_ULL(32);
 
-- 
1.9.1