linux-kernel - [PATCH 2/4] iommu/mediatek: Add iotlb_sync

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Date:   Mon, 19 Oct 2020 19:30:58 +0800
From:   Chao Hao <chao.hao@...iatek.com>
To:     Joerg Roedel <joro@...tes.org>,
        Matthias Brugger <matthias.bgg@...il.com>
CC:     <iommu@...ts.linux-foundation.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>, <wsd_upstream@...iatek.com>,
        Yong Wu <yong.wu@...iatek.com>, FY Yang <fy.yang@...iatek.com>,
        Jun Wen <jun.wen@...iatek.com>,
        Mingyuan Ma <mingyuan.ma@...iatek.com>,
        Chao Hao <chao.hao@...iatek.com>
Subject: [PATCH 2/4] iommu/mediatek: Add iotlb_sync_range() support

MTK_IOMMU driver writes one page entry and does tlb flush at a time
currently. More optimal would be to aggregate the writes and flush
BUS buffer in the end.
For 50MB buffer mapping, if mtk_iommu driver use iotlb_sync_range()
instead of tlb_add_range() and tlb_flush_walk/leaf(), it can increase
50% performance or more(depending on size of every page size) in
comparison to flushing after each page entry update. So we prefer to
use iotlb_sync_range() to replace iotlb_sync(), tlb_add_range() and
tlb_flush_walk/leaf() for MTK platforms.

Signed-off-by: Chao Hao <chao.hao@...iatek.com>
---
 drivers/iommu/mtk_iommu.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 785b228d39a6..d3400c15ff7b 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -224,6 +224,11 @@ static void mtk_iommu_tlb_flush_range_sync(unsigned long iova, size_t size,
 	}
 }
 
+static void __mtk_iommu_tlb_flush_range_sync(unsigned long iova, size_t size)
+{
+	mtk_iommu_tlb_flush_range_sync(iova, size, 0, NULL)
+}
+
 static void mtk_iommu_tlb_flush_page_nosync(struct iommu_iotlb_gather *gather,
 					    unsigned long iova, size_t granule,
 					    void *cookie)
@@ -536,6 +541,7 @@ static const struct iommu_ops mtk_iommu_ops = {
 	.map		= mtk_iommu_map,
 	.unmap		= mtk_iommu_unmap,
 	.flush_iotlb_all = mtk_iommu_flush_iotlb_all,
+	.iotlb_sync_range = __mtk_iommu_tlb_flush_range_sync,
 	.iotlb_sync	= mtk_iommu_iotlb_sync,
 	.iova_to_phys	= mtk_iommu_iova_to_phys,
 	.probe_device	= mtk_iommu_probe_device,
-- 
2.18.0