5 files changed, 155 insertions, 0 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
new file mode 100644
index 0000000000..dabc1f900d
--- /dev/null
+++ b/drivers/iommu/Kconfig
@@ -0,0 +1,27 @@
+#
+# IOMMU devices
+#
+
+menu "IOMMU device drivers"
+
+config IOMMU
+	bool "Enable Driver Model for IOMMU drivers"
+	depends on DM
+	help
+	  Enable driver model for IOMMU devices. An IOMMU maps device
+	  virtiual memory addresses to physical addresses. Devices
+	  that sit behind an IOMMU can typically only access physical
+	  memory if the IOMMU has been programmed to allow access to
+	  that memory.
+
+config APPLE_DART
+	bool "Apple DART support"
+	depends on IOMMU && ARCH_APPLE
+	default y
+	help
+	  Enable support for the DART on Apple SoCs.  The DART is Apple's
+	  IOMMU implementation.  The driver performs the necessary
+	  configuration to put the DART into bypass mode such that it can
+	  be used transparently by U-Boot.
+
+endmenu
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
new file mode 100644
index 0000000000..e3e0900e17
--- /dev/null
+++ b/drivers/iommu/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+obj-$(CONFIG_IOMMU) += iommu-uclass.o
+
+obj-$(CONFIG_APPLE_DART) += apple_dart.o
+obj-$(CONFIG_SANDBOX) += sandbox_iommu.o
diff --git a/drivers/iommu/apple_dart.c b/drivers/iommu/apple_dart.c
new file mode 100644
index 0000000000..ff8c5fa62c
--- /dev/null
+++ b/drivers/iommu/apple_dart.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Mark Kettenis <kettenis@openbsd.org>
+ */
+
+#include <common.h>
+#include <cpu_func.h>
+#include <dm.h>
+#include <asm/io.h>
+
+#define DART_PARAMS2		0x0004
+#define  DART_PARAMS2_BYPASS_SUPPORT	BIT(0)
+#define DART_TLB_OP		0x0020
+#define  DART_TLB_OP_OPMASK	(0xfff << 20)
+#define  DART_TLB_OP_FLUSH	(0x001 << 20)
+#define  DART_TLB_OP_BUSY	BIT(2)
+#define DART_TLB_OP_SIDMASK	0x0034
+#define DART_ERROR_STATUS	0x0040
+#define DART_TCR(sid)		(0x0100 + 4 * (sid))
+#define  DART_TCR_TRANSLATE_ENABLE	BIT(7)
+#define  DART_TCR_BYPASS_DART		BIT(8)
+#define  DART_TCR_BYPASS_DAPF		BIT(12)
+#define DART_TTBR(sid, idx)	(0x0200 + 16 * (sid) + 4 * (idx))
+#define  DART_TTBR_VALID	BIT(31)
+#define  DART_TTBR_SHIFT	12
+
+static int apple_dart_probe(struct udevice *dev)
+{
+	void *base;
+	int sid, i;
+
+	base = dev_read_addr_ptr(dev);
+	if (!base)
+		return -EINVAL;
+
+	u32 params2 = readl(base + DART_PARAMS2);
+	if (params2 & DART_PARAMS2_BYPASS_SUPPORT) {
+		for (sid = 0; sid < 16; sid++) {
+			writel(DART_TCR_BYPASS_DART | DART_TCR_BYPASS_DAPF,
+			       base + DART_TCR(sid));
+			for (i = 0; i < 4; i++)
+				writel(0, base + DART_TTBR(sid, i));
+		}
+	}
+
+	return 0;
+}
+
+static const struct udevice_id apple_dart_ids[] = {
+	{ .compatible = "apple,t8103-dart" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(apple_dart) = {
+	.name = "apple_dart",
+	.id = UCLASS_IOMMU,
+	.of_match = apple_dart_ids,
+	.probe = apple_dart_probe
+};
diff --git a/drivers/iommu/iommu-uclass.c b/drivers/iommu/iommu-uclass.c
new file mode 100644
index 0000000000..ed917b3c3e
--- /dev/null
+++ b/drivers/iommu/iommu-uclass.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Mark Kettenis <kettenis@openbsd.org>
+ */
+
+#define LOG_CATEGORY UCLASS_IOMMU
+
+#include <common.h>
+#include <dm.h>
+
+#if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA))
+int dev_iommu_enable(struct udevice *dev)
+{
+	struct ofnode_phandle_args args;
+	struct udevice *dev_iommu;
+	int i, count, ret = 0;
+
+	count = dev_count_phandle_with_args(dev, "iommus",
+					    "#iommu-cells", 0);
+	for (i = 0; i < count; i++) {
+		ret = dev_read_phandle_with_args(dev, "iommus",
+						 "#iommu-cells", 0, i, &args);
+		if (ret) {
+			debug("%s: dev_read_phandle_with_args failed: %d\n",
+			      __func__, ret);
+			return ret;
+		}
+
+		ret = uclass_get_device_by_ofnode(UCLASS_IOMMU, args.node,
+						  &dev_iommu);
+		if (ret) {
+			debug("%s: uclass_get_device_by_ofnode failed: %d\n",
+			      __func__, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+#endif
+
+UCLASS_DRIVER(iommu) = {
+	.id		= UCLASS_IOMMU,
+	.name		= "iommu",
+};
diff --git a/drivers/iommu/sandbox_iommu.c b/drivers/iommu/sandbox_iommu.c
new file mode 100644
index 0000000000..c8161a40ae
--- /dev/null
+++ b/drivers/iommu/sandbox_iommu.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Mark Kettenis <kettenis@openbsd.org>
+ */
+
+#include <common.h>
+#include <dm.h>
+
+static const struct udevice_id sandbox_iommu_ids[] = {
+	{ .compatible = "sandbox,iommu" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(sandbox_iommu) = {
+	.name = "sandbox_iommu",
+	.id = UCLASS_IOMMU,
+	.of_match = sandbox_iommu_ids,
+};