diff options
| author | Nate Watterson <nwatters@codeaurora.org> | 2017-01-10 14:47:13 -0500 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2017-01-26 18:16:57 +0000 |
| commit | 692c4e422dae023a5247c0c6fc3b7b89305ca974 (patch) | |
| tree | e6e8e9fadbb079dd5c61e9e6b9807a9e762fbfce /drivers/iommu | |
| parent | 810871c57011eb3e89e6768932757f169d666cd2 (diff) | |
| download | linux-692c4e422dae023a5247c0c6fc3b7b89305ca974.tar.bz2 | |
iommu/arm-smmu-v3: limit use of 2-level stream tables
In the current arm-smmu-v3 driver, all smmus that support 2-level
stream tables are being forced to use them. This is suboptimal for
smmus that support fewer stream id bits than would fill in a single
second level table. This patch limits the use of 2-level tables to
smmus that both support the feature and whose first level table can
possibly contain more than a single entry.
Signed-off-by: Nate Watterson <nwatters@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/arm-smmu-v3.c | 21 |
1 files changed, 10 insertions, 11 deletions
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 94f305db8739..947807ca9296 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -1977,17 +1977,9 @@ static int arm_smmu_init_strtab_2lvl(struct arm_smmu_device *smmu) u32 size, l1size; struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg; - /* - * If we can resolve everything with a single L2 table, then we - * just need a single L1 descriptor. Otherwise, calculate the L1 - * size, capped to the SIDSIZE. - */ - if (smmu->sid_bits < STRTAB_SPLIT) { - size = 0; - } else { - size = STRTAB_L1_SZ_SHIFT - (ilog2(STRTAB_L1_DESC_DWORDS) + 3); - size = min(size, smmu->sid_bits - STRTAB_SPLIT); - } + /* Calculate the L1 size, capped to the SIDSIZE. */ + size = STRTAB_L1_SZ_SHIFT - (ilog2(STRTAB_L1_DESC_DWORDS) + 3); + size = min(size, smmu->sid_bits - STRTAB_SPLIT); cfg->num_l1_ents = 1 << size; size += STRTAB_SPLIT; @@ -2498,6 +2490,13 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu) smmu->ssid_bits = reg >> IDR1_SSID_SHIFT & IDR1_SSID_MASK; smmu->sid_bits = reg >> IDR1_SID_SHIFT & IDR1_SID_MASK; + /* + * If the SMMU supports fewer bits than would fill a single L2 stream + * table, use a linear table instead. + */ + if (smmu->sid_bits <= STRTAB_SPLIT) + smmu->features &= ~ARM_SMMU_FEAT_2_LVL_STRTAB; + /* IDR5 */ reg = readl_relaxed(smmu->base + ARM_SMMU_IDR5); |