linux-kernel - [PATCH 5/5] iommu/sun50i: Invalidate iova at map and unmap

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Message-Id: <20221013181221.3247429-6-jernej.skrabec@gmail.com>
Date:   Thu, 13 Oct 2022 20:12:20 +0200
From:   Jernej Skrabec <jernej.skrabec@...il.com>
To:     maxime@...no.tech, joro@...tes.org, will@...nel.org,
        robin.murphy@....com, wens@...e.org, samuel@...lland.org
Cc:     iommu@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org,
        linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Jernej Skrabec <jernej.skrabec@...il.com>
Subject: [PATCH 5/5] iommu/sun50i: Invalidate iova at map and unmap

Mapped and unmapped iova addresses needs to be invalidated immediately
or otherwise they might or might not work when used by master device.

This was discovered when running video decoder conformity test with
Cedrus. Some videos were now and then decoded incorrectly and generated
page faults.

Fixes: 4100b8c229b3 ("iommu: Add Allwinner H6 IOMMU driver")
Signed-off-by: Jernej Skrabec <jernej.skrabec@...il.com>
---
 drivers/iommu/sun50i-iommu.c | 51 ++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
index 7c3b2ac552da..21e47ce6946a 100644
--- a/drivers/iommu/sun50i-iommu.c
+++ b/drivers/iommu/sun50i-iommu.c
@@ -518,6 +518,53 @@ static u32 *sun50i_dte_get_page_table(struct sun50i_iommu_domain *sun50i_domain,
 	return page_table;
 }
 
+static void sun50i_iommu_zap_iova(struct sun50i_iommu *iommu, unsigned long iova)
+{
+	unsigned long flags;
+	u32 reg;
+	int ret;
+
+	spin_lock_irqsave(&iommu->iommu_lock, flags);
+
+	iommu_write(iommu, IOMMU_AUTO_GATING_REG, 0);
+
+	iommu_write(iommu, IOMMU_TLB_IVLD_ADDR_REG, iova);
+	iommu_write(iommu, IOMMU_TLB_IVLD_ADDR_MASK_REG, GENMASK(11, 0));
+	iommu_write(iommu, IOMMU_TLB_IVLD_ENABLE_REG, IOMMU_TLB_IVLD_ENABLE_ENABLE);
+
+	ret = readl_poll_timeout_atomic(iommu->base + IOMMU_TLB_IVLD_ENABLE_REG,
+					reg, !reg, 1, 2000);
+	if (ret)
+		dev_warn(iommu->dev, "TLB invalidation timed out!\n");
+
+	iommu_write(iommu, IOMMU_AUTO_GATING_REG, IOMMU_AUTO_GATING_ENABLE);
+
+	spin_unlock_irqrestore(&iommu->iommu_lock, flags);
+}
+
+static void sun50i_iommu_zap_ptw_cache(struct sun50i_iommu *iommu, unsigned long iova)
+{
+	unsigned long flags;
+	u32 reg;
+	int ret;
+
+	spin_lock_irqsave(&iommu->iommu_lock, flags);
+
+	iommu_write(iommu, IOMMU_AUTO_GATING_REG, 0);
+
+	iommu_write(iommu, IOMMU_PC_IVLD_ADDR_REG, iova);
+	iommu_write(iommu, IOMMU_PC_IVLD_ENABLE_REG, IOMMU_PC_IVLD_ENABLE_ENABLE);
+
+	ret = readl_poll_timeout_atomic(iommu->base + IOMMU_PC_IVLD_ENABLE_REG,
+					reg, !reg, 1, 2000);
+	if (ret)
+		dev_warn(iommu->dev, "PTW cache invalidation timed out!\n");
+
+	iommu_write(iommu, IOMMU_AUTO_GATING_REG, IOMMU_AUTO_GATING_ENABLE);
+
+	spin_unlock_irqrestore(&iommu->iommu_lock, flags);
+}
+
 static int sun50i_iommu_map(struct iommu_domain *domain, unsigned long iova,
 			    phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 {
@@ -546,6 +593,8 @@ static int sun50i_iommu_map(struct iommu_domain *domain, unsigned long iova,
 
 	*pte_addr = sun50i_mk_pte(paddr, prot);
 	sun50i_table_flush(sun50i_domain, pte_addr, 1);
+	sun50i_iommu_zap_iova(iommu, iova);
+	sun50i_iommu_zap_ptw_cache(iommu, iova);
 
 out:
 	return ret;
@@ -571,6 +620,8 @@ static size_t sun50i_iommu_unmap(struct iommu_domain *domain, unsigned long iova
 
 	memset(pte_addr, 0, sizeof(*pte_addr));
 	sun50i_table_flush(sun50i_domain, pte_addr, 1);
+	sun50i_iommu_zap_iova(sun50i_domain->iommu, iova);
+	sun50i_iommu_zap_ptw_cache(sun50i_domain->iommu, iova);
 
 	return SZ_4K;
 }
-- 
2.38.0