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 2f1481ad4aa51a4dcd175babe5631fc85800a004..9305964250acaf94cef7da5ce7f5a2fb6e78b5ce 100644 (file)
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -27,6 +27,7 @@ struct tegra_smmu {
        const struct tegra_smmu_soc *soc;
 
        unsigned long pfn_mask;
+       unsigned long tlb_mask;
 
        unsigned long *asids;
        struct mutex lock;
@@ -70,7 +71,8 @@ static inline u32 smmu_readl(struct tegra_smmu *smmu, unsigned long offset)
 #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 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev,
        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 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev,
        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;

diff --git a/drivers/memory/tegra/tegra114.c b/drivers/memory/tegra/tegra114.c
index 7122f39be9ccc10ce976a8b4a9bf4b3379a08542..8053f70dbfd19266f9cbbbc220be85d8967d7d11 100644 (file)
--- a/drivers/memory/tegra/tegra114.c
+++ b/drivers/memory/tegra/tegra114.c
@@ -919,6 +919,7 @@ static const struct tegra_smmu_soc tegra114_smmu_soc = {
        .num_swgroups = ARRAY_SIZE(tegra114_swgroups),
        .supports_round_robin_arbitration = false,
        .supports_request_limit = false,
+       .num_tlb_lines = 32,
        .num_asids = 4,
 };
 

diff --git a/drivers/memory/tegra/tegra124.c b/drivers/memory/tegra/tegra124.c
index ebda63283853955c4bfe0d6a89c873970f869615..7d734befe0ed3122cce8032098345c3ff5f40d39 100644 (file)
--- a/drivers/memory/tegra/tegra124.c
+++ b/drivers/memory/tegra/tegra124.c
@@ -1029,6 +1029,7 @@ static const struct tegra_smmu_soc tegra132_smmu_soc = {
        .num_swgroups = ARRAY_SIZE(tegra124_swgroups),
        .supports_round_robin_arbitration = true,
        .supports_request_limit = true,
+       .num_tlb_lines = 32,
        .num_asids = 128,
 };
 

diff --git a/drivers/memory/tegra/tegra30.c b/drivers/memory/tegra/tegra30.c
index 3cb30b69d95bf51ab3ef93306bd301156480da53..7e0694d80edb3a3a5d63a543f15ab516b87ac0b1 100644 (file)
--- a/drivers/memory/tegra/tegra30.c
+++ b/drivers/memory/tegra/tegra30.c
@@ -941,6 +941,7 @@ static const struct tegra_smmu_soc tegra30_smmu_soc = {
        .num_swgroups = ARRAY_SIZE(tegra30_swgroups),
        .supports_round_robin_arbitration = false,
        .supports_request_limit = false,
+       .num_tlb_lines = 16,
        .num_asids = 4,
 };
 

diff --git a/include/soc/tegra/mc.h b/include/soc/tegra/mc.h
index d6c3190ec852edd2c9e52c535703c2e429e52089..8cb3a7ecd6f89a51871e830e6ca3d8e7dbc79587 100644 (file)
--- a/include/soc/tegra/mc.h
+++ b/include/soc/tegra/mc.h
@@ -61,6 +61,7 @@ struct tegra_smmu_soc {
        bool supports_round_robin_arbitration;
        bool supports_request_limit;
 
+       unsigned int num_tlb_lines;
        unsigned int num_asids;
 };