[PATCH v11 3/5] iommu/arm-smmu: add NVIDIA implementation for ARM MMU-500 usage

Krishna Reddy
2020-07-18T19:35:20Z

NVIDIA's Tegra194 SoC has three ARM MMU-500 instances.
It uses two of the ARM MMU-500s together to interleave IOVA
accesses across them and must be programmed identically.
This implementation supports programming the two ARM MMU-500s
that must be programmed identically.

The third ARM MMU-500 instance is supported by standard
arm-smmu.c driver itself.

Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Nicolin Chen <nicoleotsuka@gmail.com>
Reviewed-by: Pritesh Raithatha <praithatha@nvidia.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Krishna Reddy <vdumpa@nvidia.com>
---
MAINTAINERS | 2 +
drivers/iommu/Makefile | 2 +-
drivers/iommu/arm-smmu-impl.c | 3 +
drivers/iommu/arm-smmu-nvidia.c | 179 ++++++++++++++++++++++++++++++++
drivers/iommu/arm-smmu.c | 1 +
drivers/iommu/arm-smmu.h | 1 +
6 files changed, 187 insertions(+), 1 deletion(-)
create mode 100644 drivers/iommu/arm-smmu-nvidia.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 496fd4eafb68..ee2c0ba13a0f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16810,8 +16810,10 @@ F: drivers/i2c/busses/i2c-tegra.c

TEGRA IOMMU DRIVERS
M: Thierry Reding <thierry.reding@gmail.com>
+R: Krishna Reddy <vdumpa@nvidia.com>
L: linux-tegra@vger.kernel.org
S: Supported
+F: drivers/iommu/arm-smmu-nvidia.c
F: drivers/iommu/tegra*

TEGRA KBC DRIVER
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 342190196dfb..2b8203db73ec 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -15,7 +15,7 @@ obj-$(CONFIG_AMD_IOMMU) += amd/iommu.o amd/init.o amd/quirks.o
obj-$(CONFIG_AMD_IOMMU_DEBUGFS) += amd/debugfs.o
obj-$(CONFIG_AMD_IOMMU_V2) += amd/iommu_v2.o
obj-$(CONFIG_ARM_SMMU) += arm_smmu.o
-arm_smmu-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-qcom.o
+arm_smmu-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-nvidia.o arm-smmu-qcom.o
obj-$(CONFIG_ARM_SMMU_V3) += arm-smmu-v3.o
obj-$(CONFIG_DMAR_TABLE) += intel/dmar.o
obj-$(CONFIG_INTEL_IOMMU) += intel/iommu.o intel/pasid.o
diff --git a/drivers/iommu/arm-smmu-impl.c b/drivers/iommu/arm-smmu-impl.c
index c87d825f651e..f4ff124a1967 100644
--- a/drivers/iommu/arm-smmu-impl.c
+++ b/drivers/iommu/arm-smmu-impl.c
@@ -213,6 +213,9 @@ struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu)
if (of_property_read_bool(np, "calxeda,smmu-secure-config-access"))
smmu->impl = &calxeda_impl;

+ if (of_device_is_compatible(np, "nvidia,tegra194-smmu"))
+ return nvidia_smmu_impl_init(smmu);
+
if (of_device_is_compatible(np, "qcom,sdm845-smmu-500") ||
of_device_is_compatible(np, "qcom,sc7180-smmu-500") ||
of_device_is_compatible(np, "qcom,sm8150-smmu-500") ||
diff --git a/drivers/iommu/arm-smmu-nvidia.c b/drivers/iommu/arm-smmu-nvidia.c
new file mode 100644
index 000000000000..2f55e5793d34
--- /dev/null
+++ b/drivers/iommu/arm-smmu-nvidia.c
@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (C) 2019-2020 NVIDIA CORPORATION. All rights reserved.
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include "arm-smmu.h"
+
+/*
+ * Tegra194 has three ARM MMU-500 Instances.
+ * Two of them are used together and must be programmed identically for
+ * interleaved IOVA accesses across them and translates accesses from
+ * non-isochronous HW devices.
+ * Third one is used for translating accesses from isochronous HW devices.
+ * This implementation supports programming of the two instances that must
+ * be programmed identically.
+ * The third instance usage is through standard arm-smmu driver itself and
+ * is out of scope of this implementation.
+ */
+#define NUM_SMMU_INSTANCES 2
+
+struct nvidia_smmu {
+ struct arm_smmu_device smmu;
+ void __iomem *bases[NUM_SMMU_INSTANCES];
+};
+
+static inline void __iomem *nvidia_smmu_page(struct arm_smmu_device *smmu,
+ unsigned int inst, int page)
+{
+ struct nvidia_smmu *nvidia_smmu;
+
+ nvidia_smmu = container_of(smmu, struct nvidia_smmu, smmu);
+ return nvidia_smmu->bases[inst] + (page << smmu->pgshift);
+}
+
+static u32 nvidia_smmu_read_reg(struct arm_smmu_device *smmu,
+ int page, int offset)
+{
+ void __iomem *reg = nvidia_smmu_page(smmu, 0, page) + offset;
+
+ return readl_relaxed(reg);
+}
+
+static void nvidia_smmu_write_reg(struct arm_smmu_device *smmu,
+ int page, int offset, u32 val)
+{
+ unsigned int i;
+
+ for (i = 0; i < NUM_SMMU_INSTANCES; i++) {
+ void __iomem *reg = nvidia_smmu_page(smmu, i, page) + offset;
+
+ writel_relaxed(val, reg);
+ }
+}
+
+static u64 nvidia_smmu_read_reg64(struct arm_smmu_device *smmu,
+ int page, int offset)
+{
+ void __iomem *reg = nvidia_smmu_page(smmu, 0, page) + offset;
+
+ return readq_relaxed(reg);
+}
+
+static void nvidia_smmu_write_reg64(struct arm_smmu_device *smmu,
+ int page, int offset, u64 val)
+{
+ unsigned int i;
+
+ for (i = 0; i < NUM_SMMU_INSTANCES; i++) {
+ void __iomem *reg = nvidia_smmu_page(smmu, i, page) + offset;
+
+ writeq_relaxed(val, reg);
+ }
+}
+
+static void nvidia_smmu_tlb_sync(struct arm_smmu_device *smmu, int page,
+ int sync, int status)
+{
+ unsigned int delay;
+
+ arm_smmu_writel(smmu, page, sync, 0);
+
+ for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) {
+ unsigned int spin_cnt;
+
+ for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) {
+ u32 val = 0;
+ unsigned int i;
+
+ for (i = 0; i < NUM_SMMU_INSTANCES; i++) {
+ void __iomem *reg;
+
+ reg = nvidia_smmu_page(smmu, i, page) + status;
+ val |= readl_relaxed(reg);
+ }
+
+ if (!(val & ARM_SMMU_sTLBGSTATUS_GSACTIVE))
+ return;
+
+ cpu_relax();
+ }
+
+ udelay(delay);
+ }
+
+ dev_err_ratelimited(smmu->dev,
+ "TLB sync timed out -- SMMU may be deadlocked\n");
+}
+
+static int nvidia_smmu_reset(struct arm_smmu_device *smmu)
+{
+ unsigned int i;
+
+ for (i = 0; i < NUM_SMMU_INSTANCES; i++) {
+ u32 val;
+ void __iomem *reg = nvidia_smmu_page(smmu, i, ARM_SMMU_GR0) +
+ ARM_SMMU_GR0_sGFSR;
+
+ /* clear global FSR */
+ val = readl_relaxed(reg);
+ writel_relaxed(val, reg);
+ }
+
+ return 0;
+}
+
+static const struct arm_smmu_impl nvidia_smmu_impl = {
+ .read_reg = nvidia_smmu_read_reg,
+ .write_reg = nvidia_smmu_write_reg,
+ .read_reg64 = nvidia_smmu_read_reg64,
+ .write_reg64 = nvidia_smmu_write_reg64,
+ .reset = nvidia_smmu_reset,
+ .tlb_sync = nvidia_smmu_tlb_sync,
+};
+
+struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu)
+{
+ struct resource *res;
+ struct device *dev = smmu->dev;
+ struct nvidia_smmu *nvidia_smmu;
+ struct platform_device *pdev = to_platform_device(dev);
+
+ nvidia_smmu = devm_kzalloc(dev, sizeof(*nvidia_smmu), GFP_KERNEL);
+ if (!nvidia_smmu)
+ return ERR_PTR(-ENOMEM);
+
+ /*
+ * Copy the data from struct arm_smmu_device *smmu allocated in
+ * arm-smmu.c. The smmu from struct nvidia_smmu replaces the smmu
+ * pointer used in arm-smmu.c once this function returns.
+ * This is necessary to derive nvidia_smmu from smmu pointer passed
+ * through arm_smmu_impl function calls subsequently.
+ */
+ nvidia_smmu->smmu = *smmu;
+ /* Instance 0 is ioremapped by arm-smmu.c. */
+ nvidia_smmu->bases[0] = smmu->base;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ if (!res)
+ return ERR_PTR(-ENODEV);
+
+ nvidia_smmu->bases[1] = devm_ioremap_resource(dev, res);
+ if (IS_ERR(nvidia_smmu->bases[1]))
+ return ERR_CAST(nvidia_smmu->bases[1]);
+
+ nvidia_smmu->smmu.impl = &nvidia_smmu_impl;
+
+ /*
+ * Free the struct arm_smmu_device *smmu allocated in arm-smmu.c.
+ * Once this function returns, arm-smmu.c would use arm_smmu_device
+ * allocated as part of struct nvidia_smmu.
+ */
+ devm_kfree(dev, smmu);
+
+ return &nvidia_smmu->smmu;
+}
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index de520115d3df..35422a17f610 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1946,6 +1946,7 @@ static const struct of_device_id arm_smmu_of_match[] = {
{ .compatible = "arm,mmu-401", .data = &arm_mmu401 },
{ .compatible = "arm,mmu-500", .data = &arm_mmu500 },
{ .compatible = "cavium,smmu-v2", .data = &cavium_smmuv2 },
+ { .compatible = "nvidia,smmu-500", .data = &arm_mmu500 },
{ .compatible = "qcom,smmu-v2", .data = &qcom_smmuv2 },
{ },
};
diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h
index c7d0122a7c6c..fad63efa1a72 100644
--- a/drivers/iommu/arm-smmu.h
+++ b/drivers/iommu/arm-smmu.h
@@ -452,6 +452,7 @@ static inline void arm_smmu_writeq(struct arm_smmu_device *smmu, int page,
arm_smmu_writeq((s), ARM_SMMU_CB((s), (n)), (o), (v))

struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu);
+struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu);
struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu);

int arm_mmu500_reset(struct arm_smmu_device *smmu);