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| author | Will Deacon <will.deacon@arm.com> | 2014-07-14 20:47:39 +0200 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2014-09-16 20:13:48 +0200 |
| commit | 4cf740b0b6628bda1e5c9201ae0d4f56fc6c06a5 (patch) | |
| tree | ccd54c982e334efced7eb7888149683d106da18e /drivers/iommu/arm-smmu.c | |
| parent | Linux 3.17-rc5 (diff) | |
| download | linux-4cf740b0b6628bda1e5c9201ae0d4f56fc6c06a5.tar.xz linux-4cf740b0b6628bda1e5c9201ae0d4f56fc6c06a5.zip | |
iommu/arm-smmu: allow translation stage to be forced on the cmdline
When debugging and testing code on an SMMU that supports nested
translation, it can be useful to restrict the driver to a particular
stage of translation.
This patch adds a module parameter to the ARM SMMU driver to allow this
by restricting the ability of the probe() code to detect support for
only the specified stage.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/iommu/arm-smmu.c')
| -rw-r--r-- | drivers/iommu/arm-smmu.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index a83cc2a2a2ca..958ae8194afe 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -326,6 +326,11 @@ #define FSYNR0_WNR (1 << 4) +static int force_stage; +module_param_named(force_stage, force_stage, int, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(force_stage, + "Force SMMU mappings to be installed at a particular stage of translation. A value of '1' or '2' forces the corresponding stage. All other values are ignored (i.e. no stage is forced). Note that selecting a specific stage will disable support for nested translation."); + struct arm_smmu_smr { u8 idx; u16 mask; @@ -1716,6 +1721,13 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu) return -ENODEV; } #endif + + /* Restrict available stages based on module parameter */ + if (force_stage == 1) + id &= ~(ID0_S2TS | ID0_NTS); + else if (force_stage == 2) + id &= ~(ID0_S1TS | ID0_NTS); + if (id & ID0_S1TS) { smmu->features |= ARM_SMMU_FEAT_TRANS_S1; dev_notice(smmu->dev, "\tstage 1 translation\n"); @@ -1732,8 +1744,7 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu) } if (!(smmu->features & - (ARM_SMMU_FEAT_TRANS_S1 | ARM_SMMU_FEAT_TRANS_S2 | - ARM_SMMU_FEAT_TRANS_NESTED))) { + (ARM_SMMU_FEAT_TRANS_S1 | ARM_SMMU_FEAT_TRANS_S2))) { dev_err(smmu->dev, "\tno translation support!\n"); return -ENODEV; } |