linux-kernel - [PATCH 3/5] iommu/sun50i: Ensure bypass is disabled

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Date:   Wed, 27 Apr 2022 20:03:58 -0500
From:   Samuel Holland <samuel@...lland.org>
To:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        iommu@...ts.linux-foundation.org
Cc:     Heiko Stuebner <heiko@...ech.de>,
        Palmer Dabbelt <palmer@...belt.com>,
        linux-riscv@...ts.infradead.org,
        Samuel Holland <samuel@...lland.org>,
        Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Maxime Ripard <mripard@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-sunxi@...ts.linux.dev
Subject: [PATCH 3/5] iommu/sun50i: Ensure bypass is disabled

The H6 variant of the hardware disables bypass by default. The D1
variant of the hardware enables bypass for all masters by default.

Since the driver expects bypass to be disabled, ensure that is the case.

Signed-off-by: Samuel Holland <samuel@...lland.org>
---

 drivers/iommu/sun50i-iommu.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
index ec07b60016d3..b9e644b93637 100644
--- a/drivers/iommu/sun50i-iommu.c
+++ b/drivers/iommu/sun50i-iommu.c
@@ -374,6 +374,8 @@ static int sun50i_iommu_enable(struct sun50i_iommu *iommu)
 
 	spin_lock_irqsave(&iommu->iommu_lock, flags);
 
+	iommu_write(iommu, IOMMU_BYPASS_REG, 0);
+
 	iommu_write(iommu, IOMMU_TTB_REG, sun50i_domain->dt_dma);
 	iommu_write(iommu, IOMMU_TLB_PREFETCH_REG,
 		    IOMMU_TLB_PREFETCH_MASTER_ENABLE(0) |
-- 
2.35.1