linux-kernel - [PATCH v2 1/5] iommu/arm-smmu: Make all valid stream mappings BYPASS

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Message-Id: <20200717001619.325317-2-bjorn.andersson@linaro.org>
Date:   Thu, 16 Jul 2020 17:16:15 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Laurentiu Tudor <laurentiu.tudor@....com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Jonathan Marek <jonathan@...ek.ca>,
        linux-arm-msm@...r.kernel.org,
        John Stultz <john.stultz@...aro.org>,
        Vinod Koul <vkoul@...nel.org>
Subject: [PATCH v2 1/5] iommu/arm-smmu: Make all valid stream mappings BYPASS

Turn all stream mappings marked as valid into BYPASS. This allows the
platform specific implementation to configure stream mappings to match
the boot loader's configuration for e.g. display to continue to function
through the reset of the SMMU.

Tested-by: John Stultz <john.stultz@...aro.org>
Tested-by: Vinod Koul <vkoul@...nel.org>
Suggested-by: Robin Murphy <robin.murphy@....com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
---

Changes since v1:
- Mark arm_smmu_setup_identity() static
- Picked up tested-by tags

 drivers/iommu/arm-smmu.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 243bc4cb2705..fb85e716ae9a 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1924,6 +1924,22 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
 	return 0;
 }
 
+static int arm_smmu_setup_identity(struct arm_smmu_device *smmu)
+{
+	int i;
+
+	for (i = 0; i < smmu->num_mapping_groups; i++) {
+		if (smmu->smrs[i].valid) {
+			smmu->s2crs[i].type = S2CR_TYPE_BYPASS;
+			smmu->s2crs[i].privcfg = S2CR_PRIVCFG_DEFAULT;
+			smmu->s2crs[i].cbndx = 0xff;
+			smmu->s2crs[i].count++;
+		}
+	}
+
+	return 0;
+}
+
 struct arm_smmu_match_data {
 	enum arm_smmu_arch_version version;
 	enum arm_smmu_implementation model;
@@ -2181,6 +2197,10 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 	if (err)
 		return err;
 
+	err = arm_smmu_setup_identity(smmu);
+	if (err)
+		return err;
+
 	if (smmu->version == ARM_SMMU_V2) {
 		if (smmu->num_context_banks > smmu->num_context_irqs) {
 			dev_err(dev,
-- 
2.26.2