linux-kernel - [PATCH v4 1/4] iommu/arm-smmu: Call configuration impl hook before consuming features

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Message-Id: <20200715070649.18733-2-tn@semihalf.com>
Date:   Wed, 15 Jul 2020 09:06:46 +0200
From:   Tomasz Nowicki <tn@...ihalf.com>
To:     will@...nel.org, robin.murphy@....com, joro@...tes.org,
        gregory.clement@...tlin.com, robh+dt@...nel.org, hannah@...vell.com
Cc:     linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org,
        devicetree@...r.kernel.org, catalin.marinas@....com,
        nadavh@...vell.com, linux-arm-kernel@...ts.infradead.org,
        mw@...ihalf.com, Tomasz Nowicki <tn@...ihalf.com>
Subject: [PATCH v4 1/4] iommu/arm-smmu: Call configuration impl hook before consuming features

'cfg_probe' hook is called at the very end of configuration probing
procedure and therefore features override and workaround may become
complex like for ID register fixups. In preparation for adding Marvell
errata move 'cfg_probe' a bit earlier to have chance to adjust
the detected features before we start consuming them.

Since the Cavium quirk (the only user) does not alter features
it is safe to do so.

Suggested-by: Robin Murphy <robin.murphy@....com>
Signed-off-by: Tomasz Nowicki <tn@...ihalf.com>
---
 drivers/iommu/arm-smmu.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 243bc4cb2705..19f906de6420 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1728,7 +1728,7 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
 	unsigned int size;
 	u32 id;
 	bool cttw_reg, cttw_fw = smmu->features & ARM_SMMU_FEAT_COHERENT_WALK;
-	int i;
+	int i, ret;
 
 	dev_notice(smmu->dev, "probing hardware configuration...\n");
 	dev_notice(smmu->dev, "SMMUv%d with:\n",
@@ -1891,6 +1891,12 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
 			smmu->features |= ARM_SMMU_FEAT_FMT_AARCH64_64K;
 	}
 
+	if (smmu->impl && smmu->impl->cfg_probe) {
+		ret = smmu->impl->cfg_probe(smmu);
+		if (ret)
+			return ret;
+	}
+
 	/* Now we've corralled the various formats, what'll it do? */
 	if (smmu->features & ARM_SMMU_FEAT_FMT_AARCH32_S)
 		smmu->pgsize_bitmap |= SZ_4K | SZ_64K | SZ_1M | SZ_16M;
@@ -1918,9 +1924,6 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
 		dev_notice(smmu->dev, "\tStage-2: %lu-bit IPA -> %lu-bit PA\n",
 			   smmu->ipa_size, smmu->pa_size);
 
-	if (smmu->impl && smmu->impl->cfg_probe)
-		return smmu->impl->cfg_probe(smmu);
-
 	return 0;
 }
 
-- 
2.17.1