iommu/tegra-smmu: Parameterize number of TLB lines
The number of TLB lines was increased from 16 on Tegra30 to 32 on
Tegra114 and later. Parameterize the value so that the initial default
can be set accordingly.
On Tegra30, initializing the value to 32 would effectively disable the
TLB and hence cause massive latencies for memory accesses translated
through the SMMU. This is especially noticeable for isochronuous clients
such as display, whose FIFOs would continuously underrun.
Fixes: 891846516317 ("memory: Add NVIDIA Tegra memory controller support")
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 2f1481a..9305964 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -27,6 +27,7 @@
const struct tegra_smmu_soc *soc;
unsigned long pfn_mask;
+ unsigned long tlb_mask;
unsigned long *asids;
struct mutex lock;
@@ -70,7 +71,8 @@
#define SMMU_TLB_CONFIG 0x14
#define SMMU_TLB_CONFIG_HIT_UNDER_MISS (1 << 29)
#define SMMU_TLB_CONFIG_ROUND_ROBIN_ARBITRATION (1 << 28)
-#define SMMU_TLB_CONFIG_ACTIVE_LINES(x) ((x) & 0x3f)
+#define SMMU_TLB_CONFIG_ACTIVE_LINES(smmu) \
+ ((smmu)->soc->num_tlb_lines & (smmu)->tlb_mask)
#define SMMU_PTC_CONFIG 0x18
#define SMMU_PTC_CONFIG_ENABLE (1 << 29)
@@ -901,6 +903,9 @@
smmu->pfn_mask = BIT_MASK(mc->soc->num_address_bits - PAGE_SHIFT) - 1;
dev_dbg(dev, "address bits: %u, PFN mask: %#lx\n",
mc->soc->num_address_bits, smmu->pfn_mask);
+ smmu->tlb_mask = (smmu->soc->num_tlb_lines << 1) - 1;
+ dev_dbg(dev, "TLB lines: %u, mask: %#lx\n", smmu->soc->num_tlb_lines,
+ smmu->tlb_mask);
value = SMMU_PTC_CONFIG_ENABLE | SMMU_PTC_CONFIG_INDEX_MAP(0x3f);
@@ -910,7 +915,7 @@
smmu_writel(smmu, value, SMMU_PTC_CONFIG);
value = SMMU_TLB_CONFIG_HIT_UNDER_MISS |
- SMMU_TLB_CONFIG_ACTIVE_LINES(0x20);
+ SMMU_TLB_CONFIG_ACTIVE_LINES(smmu);
if (soc->supports_round_robin_arbitration)
value |= SMMU_TLB_CONFIG_ROUND_ROBIN_ARBITRATION;