Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1064 insertions, 0 deletions

diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
new file mode 100644
index 000000000..06ca73bdd
--- /dev/null
+++ b/drivers/iommu/apple-dart.c
@@ -0,0 +1,1064 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Apple DART (Device Address Resolution Table) IOMMU driver
+ *
+ * Copyright (C) 2021 The Asahi Linux Contributors
+ *
+ * Based on arm/arm-smmu/arm-ssmu.c and arm/arm-smmu-v3/arm-smmu-v3.c
+ *  Copyright (C) 2013 ARM Limited
+ *  Copyright (C) 2015 ARM Limited
+ * and on exynos-iommu.c
+ *  Copyright (c) 2011,2016 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/atomic.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/dev_printk.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io-pgtable.h>
+#include <linux/iommu.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_iommu.h>
+#include <linux/of_platform.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/swab.h>
+#include <linux/types.h>
+
+#include "dma-iommu.h"
+
+#define DART_MAX_STREAMS 256
+#define DART_MAX_TTBR 4
+#define MAX_DARTS_PER_DEVICE 2
+
+
+#define DART_PARAMS1 0x00
+#define DART_PARAMS_PAGE_SHIFT GENMASK(27, 24)
+
+#define DART_PARAMS2 0x04
+#define DART_PARAMS_BYPASS_SUPPORT BIT(0)
+
+#define DART_STREAM_COMMAND 0x20
+#define DART_STREAM_COMMAND_BUSY BIT(2)
+#define DART_STREAM_COMMAND_INVALIDATE BIT(20)
+
+#define DART_STREAM_SELECT 0x34
+
+#define DART_ERROR 0x40
+#define DART_ERROR_STREAM GENMASK(27, 24)
+#define DART_ERROR_CODE GENMASK(11, 0)
+#define DART_ERROR_FLAG BIT(31)
+
+#define DART_ERROR_READ_FAULT BIT(4)
+#define DART_ERROR_WRITE_FAULT BIT(3)
+#define DART_ERROR_NO_PTE BIT(2)
+#define DART_ERROR_NO_PMD BIT(1)
+#define DART_ERROR_NO_TTBR BIT(0)
+
+#define DART_CONFIG 0x60
+#define DART_CONFIG_LOCK BIT(15)
+
+#define DART_STREAM_COMMAND_BUSY_TIMEOUT 100
+
+#define DART_ERROR_ADDR_HI 0x54
+#define DART_ERROR_ADDR_LO 0x50
+
+#define DART_STREAMS_ENABLE 0xfc
+
+#define DART_TCR(sid) (0x100 + 4 * (sid))
+#define DART_TCR_TRANSLATE_ENABLE BIT(7)
+#define DART_TCR_BYPASS0_ENABLE BIT(8)
+#define DART_TCR_BYPASS1_ENABLE BIT(12)
+
+#define DART_TTBR(sid, idx) (0x200 + 16 * (sid) + 4 * (idx))
+#define DART_TTBR_VALID BIT(31)
+#define DART_TTBR_SHIFT 12
+
+struct apple_dart_hw {
+	u32 oas;
+	enum io_pgtable_fmt fmt;
+
+	int max_sid_count;
+};
+
+/*
+ * Private structure associated with each DART device.
+ *
+ * @dev: device struct
+ * @hw: SoC-specific hardware data
+ * @regs: mapped MMIO region
+ * @irq: interrupt number, can be shared with other DARTs
+ * @clks: clocks associated with this DART
+ * @num_clks: number of @clks
+ * @lock: lock for hardware operations involving this dart
+ * @pgsize: pagesize supported by this DART
+ * @supports_bypass: indicates if this DART supports bypass mode
+ * @force_bypass: force bypass mode due to pagesize mismatch?
+ * @sid2group: maps stream ids to iommu_groups
+ * @iommu: iommu core device
+ */
+struct apple_dart {
+	struct device *dev;
+	const struct apple_dart_hw *hw;
+
+	void __iomem *regs;
+
+	int irq;
+	struct clk_bulk_data *clks;
+	int num_clks;
+
+	spinlock_t lock;
+
+	u32 pgsize;
+	u32 num_streams;
+	u32 supports_bypass : 1;
+	u32 force_bypass : 1;
+
+	struct iommu_group *sid2group[DART_MAX_STREAMS];
+	struct iommu_device iommu;
+
+	u32 save_tcr[DART_MAX_STREAMS];
+	u32 save_ttbr[DART_MAX_STREAMS][DART_MAX_TTBR];
+};
+
+/*
+ * Convenience struct to identify streams.
+ *
+ * The normal variant is used inside apple_dart_master_cfg which isn't written
+ * to concurrently.
+ * The atomic variant is used inside apple_dart_domain where we have to guard
+ * against races from potential parallel calls to attach/detach_device.
+ * Note that even inside the atomic variant the apple_dart pointer is not
+ * protected: This pointer is initialized once under the domain init mutex
+ * and never changed again afterwards. Devices with different dart pointers
+ * cannot be attached to the same domain.
+ *
+ * @dart dart pointer
+ * @sid stream id bitmap
+ */
+struct apple_dart_stream_map {
+	struct apple_dart *dart;
+	DECLARE_BITMAP(sidmap, DART_MAX_STREAMS);
+};
+struct apple_dart_atomic_stream_map {
+	struct apple_dart *dart;
+	atomic_long_t sidmap[BITS_TO_LONGS(DART_MAX_STREAMS)];
+};
+
+/*
+ * This structure is attached to each iommu domain handled by a DART.
+ *
+ * @pgtbl_ops: pagetable ops allocated by io-pgtable
+ * @finalized: true if the domain has been completely initialized
+ * @init_lock: protects domain initialization
+ * @stream_maps: streams attached to this domain (valid for DMA/UNMANAGED only)
+ * @domain: core iommu domain pointer
+ */
+struct apple_dart_domain {
+	struct io_pgtable_ops *pgtbl_ops;
+
+	bool finalized;
+	struct mutex init_lock;
+	struct apple_dart_atomic_stream_map stream_maps[MAX_DARTS_PER_DEVICE];
+
+	struct iommu_domain domain;
+};
+
+/*
+ * This structure is attached to devices with dev_iommu_priv_set() on of_xlate
+ * and contains a list of streams bound to this device.
+ * So far the worst case seen is a single device with two streams
+ * from different darts, such that this simple static array is enough.
+ *
+ * @streams: streams for this device
+ */
+struct apple_dart_master_cfg {
+	struct apple_dart_stream_map stream_maps[MAX_DARTS_PER_DEVICE];
+};
+
+/*
+ * Helper macro to iterate over apple_dart_master_cfg.stream_maps and
+ * apple_dart_domain.stream_maps
+ *
+ * @i int used as loop variable
+ * @base pointer to base struct (apple_dart_master_cfg or apple_dart_domain)
+ * @stream pointer to the apple_dart_streams struct for each loop iteration
+ */
+#define for_each_stream_map(i, base, stream_map)                               \
+	for (i = 0, stream_map = &(base)->stream_maps[0];                      \
+	     i < MAX_DARTS_PER_DEVICE && stream_map->dart;                     \
+	     stream_map = &(base)->stream_maps[++i])
+
+static struct platform_driver apple_dart_driver;
+static const struct iommu_ops apple_dart_iommu_ops;
+
+static struct apple_dart_domain *to_dart_domain(struct iommu_domain *dom)
+{
+	return container_of(dom, struct apple_dart_domain, domain);
+}
+
+static void
+apple_dart_hw_enable_translation(struct apple_dart_stream_map *stream_map)
+{
+	struct apple_dart *dart = stream_map->dart;
+	int sid;
+
+	for_each_set_bit(sid, stream_map->sidmap, dart->num_streams)
+		writel(DART_TCR_TRANSLATE_ENABLE,
+		       dart->regs + DART_TCR(sid));
+}
+
+static void apple_dart_hw_disable_dma(struct apple_dart_stream_map *stream_map)
+{
+	struct apple_dart *dart = stream_map->dart;
+	int sid;
+
+	for_each_set_bit(sid, stream_map->sidmap, dart->num_streams)
+		writel(0, dart->regs + DART_TCR(sid));
+}
+
+static void
+apple_dart_hw_enable_bypass(struct apple_dart_stream_map *stream_map)
+{
+	struct apple_dart *dart = stream_map->dart;
+	int sid;
+
+	WARN_ON(!stream_map->dart->supports_bypass);
+	for_each_set_bit(sid, stream_map->sidmap, dart->num_streams)
+		writel(DART_TCR_BYPASS0_ENABLE | DART_TCR_BYPASS1_ENABLE,
+		       dart->regs + DART_TCR(sid));
+}
+
+static void apple_dart_hw_set_ttbr(struct apple_dart_stream_map *stream_map,
+				   u8 idx, phys_addr_t paddr)
+{
+	struct apple_dart *dart = stream_map->dart;
+	int sid;
+
+	WARN_ON(paddr & ((1 << DART_TTBR_SHIFT) - 1));
+	for_each_set_bit(sid, stream_map->sidmap, dart->num_streams)
+		writel(DART_TTBR_VALID | (paddr >> DART_TTBR_SHIFT),
+		       dart->regs + DART_TTBR(sid, idx));
+}
+
+static void apple_dart_hw_clear_ttbr(struct apple_dart_stream_map *stream_map,
+				     u8 idx)
+{
+	struct apple_dart *dart = stream_map->dart;
+	int sid;
+
+	for_each_set_bit(sid, stream_map->sidmap, dart->num_streams)
+		writel(0, dart->regs + DART_TTBR(sid, idx));
+}
+
+static void
+apple_dart_hw_clear_all_ttbrs(struct apple_dart_stream_map *stream_map)
+{
+	int i;
+
+	for (i = 0; i < DART_MAX_TTBR; ++i)
+		apple_dart_hw_clear_ttbr(stream_map, i);
+}
+
+static int
+apple_dart_hw_stream_command(struct apple_dart_stream_map *stream_map,
+			     u32 command)
+{
+	unsigned long flags;
+	int ret;
+	u32 command_reg;
+
+	spin_lock_irqsave(&stream_map->dart->lock, flags);
+
+	writel(stream_map->sidmap[0], stream_map->dart->regs + DART_STREAM_SELECT);
+	writel(command, stream_map->dart->regs + DART_STREAM_COMMAND);
+
+	ret = readl_poll_timeout_atomic(
+		stream_map->dart->regs + DART_STREAM_COMMAND, command_reg,
+		!(command_reg & DART_STREAM_COMMAND_BUSY), 1,
+		DART_STREAM_COMMAND_BUSY_TIMEOUT);
+
+	spin_unlock_irqrestore(&stream_map->dart->lock, flags);
+
+	if (ret) {
+		dev_err(stream_map->dart->dev,
+			"busy bit did not clear after command %x for streams %lx\n",
+			command, stream_map->sidmap[0]);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int
+apple_dart_hw_invalidate_tlb(struct apple_dart_stream_map *stream_map)
+{
+	return apple_dart_hw_stream_command(stream_map,
+					    DART_STREAM_COMMAND_INVALIDATE);
+}
+
+static int apple_dart_hw_reset(struct apple_dart *dart)
+{
+	u32 config;
+	struct apple_dart_stream_map stream_map;
+	int i;
+
+	config = readl(dart->regs + DART_CONFIG);
+	if (config & DART_CONFIG_LOCK) {
+		dev_err(dart->dev, "DART is locked down until reboot: %08x\n",
+			config);
+		return -EINVAL;
+	}
+
+	stream_map.dart = dart;
+	bitmap_zero(stream_map.sidmap, DART_MAX_STREAMS);
+	bitmap_set(stream_map.sidmap, 0, dart->num_streams);
+	apple_dart_hw_disable_dma(&stream_map);
+	apple_dart_hw_clear_all_ttbrs(&stream_map);
+
+	/* enable all streams globally since TCR is used to control isolation */
+	for (i = 0; i < BITS_TO_U32(dart->num_streams); i++)
+		writel(U32_MAX, dart->regs + DART_STREAMS_ENABLE + 4 * i);
+
+	/* clear any pending errors before the interrupt is unmasked */
+	writel(readl(dart->regs + DART_ERROR), dart->regs + DART_ERROR);
+
+	return apple_dart_hw_invalidate_tlb(&stream_map);
+}
+
+static void apple_dart_domain_flush_tlb(struct apple_dart_domain *domain)
+{
+	int i, j;
+	struct apple_dart_atomic_stream_map *domain_stream_map;
+	struct apple_dart_stream_map stream_map;
+
+	for_each_stream_map(i, domain, domain_stream_map) {
+		stream_map.dart = domain_stream_map->dart;
+
+		for (j = 0; j < BITS_TO_LONGS(stream_map.dart->num_streams); j++)
+			stream_map.sidmap[j] = atomic_long_read(&domain_stream_map->sidmap[j]);
+
+		apple_dart_hw_invalidate_tlb(&stream_map);
+	}
+}
+
+static void apple_dart_flush_iotlb_all(struct iommu_domain *domain)
+{
+	apple_dart_domain_flush_tlb(to_dart_domain(domain));
+}
+
+static void apple_dart_iotlb_sync(struct iommu_domain *domain,
+				  struct iommu_iotlb_gather *gather)
+{
+	apple_dart_domain_flush_tlb(to_dart_domain(domain));
+}
+
+static void apple_dart_iotlb_sync_map(struct iommu_domain *domain,
+				      unsigned long iova, size_t size)
+{
+	apple_dart_domain_flush_tlb(to_dart_domain(domain));
+}
+
+static phys_addr_t apple_dart_iova_to_phys(struct iommu_domain *domain,
+					   dma_addr_t iova)
+{
+	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
+	struct io_pgtable_ops *ops = dart_domain->pgtbl_ops;
+
+	if (!ops)
+		return 0;
+
+	return ops->iova_to_phys(ops, iova);
+}
+
+static int apple_dart_map_pages(struct iommu_domain *domain, unsigned long iova,
+				phys_addr_t paddr, size_t pgsize,
+				size_t pgcount, int prot, gfp_t gfp,
+				size_t *mapped)
+{
+	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
+	struct io_pgtable_ops *ops = dart_domain->pgtbl_ops;
+
+	if (!ops)
+		return -ENODEV;
+
+	return ops->map_pages(ops, iova, paddr, pgsize, pgcount, prot, gfp,
+			      mapped);
+}
+
+static size_t apple_dart_unmap_pages(struct iommu_domain *domain,
+				     unsigned long iova, size_t pgsize,
+				     size_t pgcount,
+				     struct iommu_iotlb_gather *gather)
+{
+	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
+	struct io_pgtable_ops *ops = dart_domain->pgtbl_ops;
+
+	return ops->unmap_pages(ops, iova, pgsize, pgcount, gather);
+}
+
+static void
+apple_dart_setup_translation(struct apple_dart_domain *domain,
+			     struct apple_dart_stream_map *stream_map)
+{
+	int i;
+	struct io_pgtable_cfg *pgtbl_cfg =
+		&io_pgtable_ops_to_pgtable(domain->pgtbl_ops)->cfg;
+
+	for (i = 0; i < pgtbl_cfg->apple_dart_cfg.n_ttbrs; ++i)
+		apple_dart_hw_set_ttbr(stream_map, i,
+				       pgtbl_cfg->apple_dart_cfg.ttbr[i]);
+	for (; i < DART_MAX_TTBR; ++i)
+		apple_dart_hw_clear_ttbr(stream_map, i);
+
+	apple_dart_hw_enable_translation(stream_map);
+	apple_dart_hw_invalidate_tlb(stream_map);
+}
+
+static int apple_dart_finalize_domain(struct iommu_domain *domain,
+				      struct apple_dart_master_cfg *cfg)
+{
+	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
+	struct apple_dart *dart = cfg->stream_maps[0].dart;
+	struct io_pgtable_cfg pgtbl_cfg;
+	int ret = 0;
+	int i, j;
+
+	mutex_lock(&dart_domain->init_lock);
+
+	if (dart_domain->finalized)
+		goto done;
+
+	for (i = 0; i < MAX_DARTS_PER_DEVICE; ++i) {
+		dart_domain->stream_maps[i].dart = cfg->stream_maps[i].dart;
+		for (j = 0; j < BITS_TO_LONGS(dart->num_streams); j++)
+			atomic_long_set(&dart_domain->stream_maps[i].sidmap[j],
+					cfg->stream_maps[i].sidmap[j]);
+	}
+
+	pgtbl_cfg = (struct io_pgtable_cfg){
+		.pgsize_bitmap = dart->pgsize,
+		.ias = 32,
+		.oas = dart->hw->oas,
+		.coherent_walk = 1,
+		.iommu_dev = dart->dev,
+	};
+
+	dart_domain->pgtbl_ops =
+		alloc_io_pgtable_ops(dart->hw->fmt, &pgtbl_cfg, domain);
+	if (!dart_domain->pgtbl_ops) {
+		ret = -ENOMEM;
+		goto done;
+	}
+
+	domain->pgsize_bitmap = pgtbl_cfg.pgsize_bitmap;
+	domain->geometry.aperture_start = 0;
+	domain->geometry.aperture_end = DMA_BIT_MASK(32);
+	domain->geometry.force_aperture = true;
+
+	dart_domain->finalized = true;
+
+done:
+	mutex_unlock(&dart_domain->init_lock);
+	return ret;
+}
+
+static int
+apple_dart_mod_streams(struct apple_dart_atomic_stream_map *domain_maps,
+		       struct apple_dart_stream_map *master_maps,
+		       bool add_streams)
+{
+	int i, j;
+
+	for (i = 0; i < MAX_DARTS_PER_DEVICE; ++i) {
+		if (domain_maps[i].dart != master_maps[i].dart)
+			return -EINVAL;
+	}
+
+	for (i = 0; i < MAX_DARTS_PER_DEVICE; ++i) {
+		if (!domain_maps[i].dart)
+			break;
+		for (j = 0; j < BITS_TO_LONGS(domain_maps[i].dart->num_streams); j++) {
+			if (add_streams)
+				atomic_long_or(master_maps[i].sidmap[j],
+					       &domain_maps[i].sidmap[j]);
+			else
+				atomic_long_and(~master_maps[i].sidmap[j],
+						&domain_maps[i].sidmap[j]);
+		}
+	}
+
+	return 0;
+}
+
+static int apple_dart_domain_add_streams(struct apple_dart_domain *domain,
+					 struct apple_dart_master_cfg *cfg)
+{
+	return apple_dart_mod_streams(domain->stream_maps, cfg->stream_maps,
+				      true);
+}
+
+static int apple_dart_domain_remove_streams(struct apple_dart_domain *domain,
+					    struct apple_dart_master_cfg *cfg)
+{
+	return apple_dart_mod_streams(domain->stream_maps, cfg->stream_maps,
+				      false);
+}
+
+static int apple_dart_attach_dev(struct iommu_domain *domain,
+				 struct device *dev)
+{
+	int ret, i;
+	struct apple_dart_stream_map *stream_map;
+	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
+	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
+
+	if (cfg->stream_maps[0].dart->force_bypass &&
+	    domain->type != IOMMU_DOMAIN_IDENTITY)
+		return -EINVAL;
+	if (!cfg->stream_maps[0].dart->supports_bypass &&
+	    domain->type == IOMMU_DOMAIN_IDENTITY)
+		return -EINVAL;
+
+	ret = apple_dart_finalize_domain(domain, cfg);
+	if (ret)
+		return ret;
+
+	switch (domain->type) {
+	case IOMMU_DOMAIN_DMA:
+	case IOMMU_DOMAIN_UNMANAGED:
+		ret = apple_dart_domain_add_streams(dart_domain, cfg);
+		if (ret)
+			return ret;
+
+		for_each_stream_map(i, cfg, stream_map)
+			apple_dart_setup_translation(dart_domain, stream_map);
+		break;
+	case IOMMU_DOMAIN_BLOCKED:
+		for_each_stream_map(i, cfg, stream_map)
+			apple_dart_hw_disable_dma(stream_map);
+		break;
+	case IOMMU_DOMAIN_IDENTITY:
+		for_each_stream_map(i, cfg, stream_map)
+			apple_dart_hw_enable_bypass(stream_map);
+		break;
+	}
+
+	return ret;
+}
+
+static void apple_dart_detach_dev(struct iommu_domain *domain,
+				  struct device *dev)
+{
+	int i;
+	struct apple_dart_stream_map *stream_map;
+	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
+	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
+
+	for_each_stream_map(i, cfg, stream_map)
+		apple_dart_hw_disable_dma(stream_map);
+
+	if (domain->type == IOMMU_DOMAIN_DMA ||
+	    domain->type == IOMMU_DOMAIN_UNMANAGED)
+		apple_dart_domain_remove_streams(dart_domain, cfg);
+}
+
+static struct iommu_device *apple_dart_probe_device(struct device *dev)
+{
+	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
+	struct apple_dart_stream_map *stream_map;
+	int i;
+
+	if (!cfg)
+		return ERR_PTR(-ENODEV);
+
+	for_each_stream_map(i, cfg, stream_map)
+		device_link_add(
+			dev, stream_map->dart->dev,
+			DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER);
+
+	return &cfg->stream_maps[0].dart->iommu;
+}
+
+static void apple_dart_release_device(struct device *dev)
+{
+	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
+
+	dev_iommu_priv_set(dev, NULL);
+	kfree(cfg);
+}
+
+static struct iommu_domain *apple_dart_domain_alloc(unsigned int type)
+{
+	struct apple_dart_domain *dart_domain;
+
+	if (type != IOMMU_DOMAIN_DMA && type != IOMMU_DOMAIN_UNMANAGED &&
+	    type != IOMMU_DOMAIN_IDENTITY && type != IOMMU_DOMAIN_BLOCKED)
+		return NULL;
+
+	dart_domain = kzalloc(sizeof(*dart_domain), GFP_KERNEL);
+	if (!dart_domain)
+		return NULL;
+
+	mutex_init(&dart_domain->init_lock);
+
+	/* no need to allocate pgtbl_ops or do any other finalization steps */
+	if (type == IOMMU_DOMAIN_IDENTITY || type == IOMMU_DOMAIN_BLOCKED)
+		dart_domain->finalized = true;
+
+	return &dart_domain->domain;
+}
+
+static void apple_dart_domain_free(struct iommu_domain *domain)
+{
+	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
+
+	if (dart_domain->pgtbl_ops)
+		free_io_pgtable_ops(dart_domain->pgtbl_ops);
+
+	kfree(dart_domain);
+}
+
+static int apple_dart_of_xlate(struct device *dev, struct of_phandle_args *args)
+{
+	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
+	struct platform_device *iommu_pdev = of_find_device_by_node(args->np);
+	struct apple_dart *dart = platform_get_drvdata(iommu_pdev);
+	struct apple_dart *cfg_dart;
+	int i, sid;
+
+	if (args->args_count != 1)
+		return -EINVAL;
+	sid = args->args[0];
+
+	if (!cfg)
+		cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
+	if (!cfg)
+		return -ENOMEM;
+	dev_iommu_priv_set(dev, cfg);
+
+	cfg_dart = cfg->stream_maps[0].dart;
+	if (cfg_dart) {
+		if (cfg_dart->supports_bypass != dart->supports_bypass)
+			return -EINVAL;
+		if (cfg_dart->force_bypass != dart->force_bypass)
+			return -EINVAL;
+		if (cfg_dart->pgsize != dart->pgsize)
+			return -EINVAL;
+	}
+
+	for (i = 0; i < MAX_DARTS_PER_DEVICE; ++i) {
+		if (cfg->stream_maps[i].dart == dart) {
+			set_bit(sid, cfg->stream_maps[i].sidmap);
+			return 0;
+		}
+	}
+	for (i = 0; i < MAX_DARTS_PER_DEVICE; ++i) {
+		if (!cfg->stream_maps[i].dart) {
+			cfg->stream_maps[i].dart = dart;
+			set_bit(sid, cfg->stream_maps[i].sidmap);
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static DEFINE_MUTEX(apple_dart_groups_lock);
+
+static void apple_dart_release_group(void *iommu_data)
+{
+	int i, sid;
+	struct apple_dart_stream_map *stream_map;
+	struct apple_dart_master_cfg *group_master_cfg = iommu_data;
+
+	mutex_lock(&apple_dart_groups_lock);
+
+	for_each_stream_map(i, group_master_cfg, stream_map)
+		for_each_set_bit(sid, stream_map->sidmap, stream_map->dart->num_streams)
+			stream_map->dart->sid2group[sid] = NULL;
+
+	kfree(iommu_data);
+	mutex_unlock(&apple_dart_groups_lock);
+}
+
+static int apple_dart_merge_master_cfg(struct apple_dart_master_cfg *dst,
+				       struct apple_dart_master_cfg *src)
+{
+	/*
+	 * We know that this function is only called for groups returned from
+	 * pci_device_group and that all Apple Silicon platforms never spread
+	 * PCIe devices from the same bus across multiple DARTs such that we can
+	 * just assume that both src and dst only have the same single DART.
+	 */
+	if (src->stream_maps[1].dart)
+		return -EINVAL;
+	if (dst->stream_maps[1].dart)
+		return -EINVAL;
+	if (src->stream_maps[0].dart != dst->stream_maps[0].dart)
+		return -EINVAL;
+
+	bitmap_or(dst->stream_maps[0].sidmap,
+		  dst->stream_maps[0].sidmap,
+		  src->stream_maps[0].sidmap,
+		  dst->stream_maps[0].dart->num_streams);
+	return 0;
+}
+
+static struct iommu_group *apple_dart_device_group(struct device *dev)
+{
+	int i, sid;
+	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
+	struct apple_dart_stream_map *stream_map;
+	struct apple_dart_master_cfg *group_master_cfg;
+	struct iommu_group *group = NULL;
+	struct iommu_group *res = ERR_PTR(-EINVAL);
+
+	mutex_lock(&apple_dart_groups_lock);
+
+	for_each_stream_map(i, cfg, stream_map) {
+		for_each_set_bit(sid, stream_map->sidmap, stream_map->dart->num_streams) {
+			struct iommu_group *stream_group =
+				stream_map->dart->sid2group[sid];
+
+			if (group && group != stream_group) {
+				res = ERR_PTR(-EINVAL);
+				goto out;
+			}
+
+			group = stream_group;
+		}
+	}
+
+	if (group) {
+		res = iommu_group_ref_get(group);
+		goto out;
+	}
+
+#ifdef CONFIG_PCI
+	if (dev_is_pci(dev))
+		group = pci_device_group(dev);
+	else
+#endif
+		group = generic_device_group(dev);
+
+	res = ERR_PTR(-ENOMEM);
+	if (!group)
+		goto out;
+
+	group_master_cfg = iommu_group_get_iommudata(group);
+	if (group_master_cfg) {
+		int ret;
+
+		ret = apple_dart_merge_master_cfg(group_master_cfg, cfg);
+		if (ret) {
+			dev_err(dev, "Failed to merge DART IOMMU grups.\n");
+			iommu_group_put(group);
+			res = ERR_PTR(ret);
+			goto out;
+		}
+	} else {
+		group_master_cfg = kmemdup(cfg, sizeof(*group_master_cfg),
+					   GFP_KERNEL);
+		if (!group_master_cfg) {
+			iommu_group_put(group);
+			goto out;
+		}
+
+		iommu_group_set_iommudata(group, group_master_cfg,
+			apple_dart_release_group);
+	}
+
+	for_each_stream_map(i, cfg, stream_map)
+		for_each_set_bit(sid, stream_map->sidmap, stream_map->dart->num_streams)
+			stream_map->dart->sid2group[sid] = group;
+
+	res = group;
+
+out:
+	mutex_unlock(&apple_dart_groups_lock);
+	return res;
+}
+
+static int apple_dart_def_domain_type(struct device *dev)
+{
+	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
+
+	if (cfg->stream_maps[0].dart->force_bypass)
+		return IOMMU_DOMAIN_IDENTITY;
+	if (!cfg->stream_maps[0].dart->supports_bypass)
+		return IOMMU_DOMAIN_DMA;
+
+	return 0;
+}
+
+#ifndef CONFIG_PCIE_APPLE_MSI_DOORBELL_ADDR
+/* Keep things compiling when CONFIG_PCI_APPLE isn't selected */
+#define CONFIG_PCIE_APPLE_MSI_DOORBELL_ADDR	0
+#endif
+#define DOORBELL_ADDR	(CONFIG_PCIE_APPLE_MSI_DOORBELL_ADDR & PAGE_MASK)
+
+static void apple_dart_get_resv_regions(struct device *dev,
+					struct list_head *head)
+{
+	if (IS_ENABLED(CONFIG_PCIE_APPLE) && dev_is_pci(dev)) {
+		struct iommu_resv_region *region;
+		int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
+
+		region = iommu_alloc_resv_region(DOORBELL_ADDR,
+						 PAGE_SIZE, prot,
+						 IOMMU_RESV_MSI, GFP_KERNEL);
+		if (!region)
+			return;
+
+		list_add_tail(&region->list, head);
+	}
+
+	iommu_dma_get_resv_regions(dev, head);
+}
+
+static const struct iommu_ops apple_dart_iommu_ops = {
+	.domain_alloc = apple_dart_domain_alloc,
+	.probe_device = apple_dart_probe_device,
+	.release_device = apple_dart_release_device,
+	.device_group = apple_dart_device_group,
+	.of_xlate = apple_dart_of_xlate,
+	.def_domain_type = apple_dart_def_domain_type,
+	.get_resv_regions = apple_dart_get_resv_regions,
+	.pgsize_bitmap = -1UL, /* Restricted during dart probe */
+	.owner = THIS_MODULE,
+	.default_domain_ops = &(const struct iommu_domain_ops) {
+		.attach_dev	= apple_dart_attach_dev,
+		.detach_dev	= apple_dart_detach_dev,
+		.map_pages	= apple_dart_map_pages,
+		.unmap_pages	= apple_dart_unmap_pages,
+		.flush_iotlb_all = apple_dart_flush_iotlb_all,
+		.iotlb_sync	= apple_dart_iotlb_sync,
+		.iotlb_sync_map	= apple_dart_iotlb_sync_map,
+		.iova_to_phys	= apple_dart_iova_to_phys,
+		.free		= apple_dart_domain_free,
+	}
+};
+
+static irqreturn_t apple_dart_irq(int irq, void *dev)
+{
+	struct apple_dart *dart = dev;
+	const char *fault_name = NULL;
+	u32 error = readl(dart->regs + DART_ERROR);
+	u32 error_code = FIELD_GET(DART_ERROR_CODE, error);
+	u32 addr_lo = readl(dart->regs + DART_ERROR_ADDR_LO);
+	u32 addr_hi = readl(dart->regs + DART_ERROR_ADDR_HI);
+	u64 addr = addr_lo | (((u64)addr_hi) << 32);
+	u8 stream_idx = FIELD_GET(DART_ERROR_STREAM, error);
+
+	if (!(error & DART_ERROR_FLAG))
+		return IRQ_NONE;
+
+	/* there should only be a single bit set but let's use == to be sure */
+	if (error_code == DART_ERROR_READ_FAULT)
+		fault_name = "READ FAULT";
+	else if (error_code == DART_ERROR_WRITE_FAULT)
+		fault_name = "WRITE FAULT";
+	else if (error_code == DART_ERROR_NO_PTE)
+		fault_name = "NO PTE FOR IOVA";
+	else if (error_code == DART_ERROR_NO_PMD)
+		fault_name = "NO PMD FOR IOVA";
+	else if (error_code == DART_ERROR_NO_TTBR)
+		fault_name = "NO TTBR FOR IOVA";
+	else
+		fault_name = "unknown";
+
+	dev_err_ratelimited(
+		dart->dev,
+		"translation fault: status:0x%x stream:%d code:0x%x (%s) at 0x%llx",
+		error, stream_idx, error_code, fault_name, addr);
+
+	writel(error, dart->regs + DART_ERROR);
+	return IRQ_HANDLED;
+}
+
+static int apple_dart_probe(struct platform_device *pdev)
+{
+	int ret;
+	u32 dart_params[2];
+	struct resource *res;
+	struct apple_dart *dart;
+	struct device *dev = &pdev->dev;
+
+	dart = devm_kzalloc(dev, sizeof(*dart), GFP_KERNEL);
+	if (!dart)
+		return -ENOMEM;
+
+	dart->dev = dev;
+	dart->hw = of_device_get_match_data(dev);
+	spin_lock_init(&dart->lock);
+
+	dart->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(dart->regs))
+		return PTR_ERR(dart->regs);
+
+	if (resource_size(res) < 0x4000) {
+		dev_err(dev, "MMIO region too small (%pr)\n", res);
+		return -EINVAL;
+	}
+
+	dart->irq = platform_get_irq(pdev, 0);
+	if (dart->irq < 0)
+		return -ENODEV;
+
+	ret = devm_clk_bulk_get_all(dev, &dart->clks);
+	if (ret < 0)
+		return ret;
+	dart->num_clks = ret;
+
+	ret = clk_bulk_prepare_enable(dart->num_clks, dart->clks);
+	if (ret)
+		return ret;
+
+	dart_params[0] = readl(dart->regs + DART_PARAMS1);
+	dart_params[1] = readl(dart->regs + DART_PARAMS2);
+	dart->pgsize = 1 << FIELD_GET(DART_PARAMS_PAGE_SHIFT, dart_params[0]);
+	dart->supports_bypass = dart_params[1] & DART_PARAMS_BYPASS_SUPPORT;
+
+	dart->num_streams = dart->hw->max_sid_count;
+
+	if (dart->num_streams > DART_MAX_STREAMS) {
+		dev_err(&pdev->dev, "Too many streams (%d > %d)\n",
+			dart->num_streams, DART_MAX_STREAMS);
+		ret = -EINVAL;
+		goto err_clk_disable;
+	}
+
+	dart->force_bypass = dart->pgsize > PAGE_SIZE;
+
+	ret = apple_dart_hw_reset(dart);
+	if (ret)
+		goto err_clk_disable;
+
+	ret = request_irq(dart->irq, apple_dart_irq, IRQF_SHARED,
+			  "apple-dart fault handler", dart);
+	if (ret)
+		goto err_clk_disable;
+
+	platform_set_drvdata(pdev, dart);
+
+	ret = iommu_device_sysfs_add(&dart->iommu, dev, NULL, "apple-dart.%s",
+				     dev_name(&pdev->dev));
+	if (ret)
+		goto err_free_irq;
+
+	ret = iommu_device_register(&dart->iommu, &apple_dart_iommu_ops, dev);
+	if (ret)
+		goto err_sysfs_remove;
+
+	dev_info(
+		&pdev->dev,
+		"DART [pagesize %x, %d streams, bypass support: %d, bypass forced: %d] initialized\n",
+		dart->pgsize, dart->num_streams, dart->supports_bypass, dart->force_bypass);
+	return 0;
+
+err_sysfs_remove:
+	iommu_device_sysfs_remove(&dart->iommu);
+err_free_irq:
+	free_irq(dart->irq, dart);
+err_clk_disable:
+	clk_bulk_disable_unprepare(dart->num_clks, dart->clks);
+
+	return ret;
+}
+
+static int apple_dart_remove(struct platform_device *pdev)
+{
+	struct apple_dart *dart = platform_get_drvdata(pdev);
+
+	apple_dart_hw_reset(dart);
+	free_irq(dart->irq, dart);
+
+	iommu_device_unregister(&dart->iommu);
+	iommu_device_sysfs_remove(&dart->iommu);
+
+	clk_bulk_disable_unprepare(dart->num_clks, dart->clks);
+
+	return 0;
+}
+
+static const struct apple_dart_hw apple_dart_hw_t8103 = {
+	.oas = 36,
+	.fmt = APPLE_DART,
+	.max_sid_count = 16,
+};
+static const struct apple_dart_hw apple_dart_hw_t6000 = {
+	.oas = 42,
+	.fmt = APPLE_DART2,
+	.max_sid_count = 16,
+};
+
+static __maybe_unused int apple_dart_suspend(struct device *dev)
+{
+	struct apple_dart *dart = dev_get_drvdata(dev);
+	unsigned int sid, idx;
+
+	for (sid = 0; sid < dart->num_streams; sid++) {
+		dart->save_tcr[sid] = readl_relaxed(dart->regs + DART_TCR(sid));
+		for (idx = 0; idx < DART_MAX_TTBR; idx++)
+			dart->save_ttbr[sid][idx] =
+				readl(dart->regs + DART_TTBR(sid, idx));
+	}
+
+	return 0;
+}
+
+static __maybe_unused int apple_dart_resume(struct device *dev)
+{
+	struct apple_dart *dart = dev_get_drvdata(dev);
+	unsigned int sid, idx;
+	int ret;
+
+	ret = apple_dart_hw_reset(dart);
+	if (ret) {
+		dev_err(dev, "Failed to reset DART on resume\n");
+		return ret;
+	}
+
+	for (sid = 0; sid < dart->num_streams; sid++) {
+		for (idx = 0; idx < DART_MAX_TTBR; idx++)
+			writel(dart->save_ttbr[sid][idx],
+			       dart->regs + DART_TTBR(sid, idx));
+		writel(dart->save_tcr[sid], dart->regs + DART_TCR(sid));
+	}
+
+	return 0;
+}
+
+DEFINE_SIMPLE_DEV_PM_OPS(apple_dart_pm_ops, apple_dart_suspend, apple_dart_resume);
+
+static const struct of_device_id apple_dart_of_match[] = {
+	{ .compatible = "apple,t8103-dart", .data = &apple_dart_hw_t8103 },
+	{ .compatible = "apple,t6000-dart", .data = &apple_dart_hw_t6000 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, apple_dart_of_match);
+
+static struct platform_driver apple_dart_driver = {
+	.driver	= {
+		.name			= "apple-dart",
+		.of_match_table		= apple_dart_of_match,
+		.suppress_bind_attrs    = true,
+		.pm			= pm_sleep_ptr(&apple_dart_pm_ops),
+	},
+	.probe	= apple_dart_probe,
+	.remove	= apple_dart_remove,
+};
+
+module_platform_driver(apple_dart_driver);
+
+MODULE_DESCRIPTION("IOMMU API for Apple's DART");
+MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
+MODULE_LICENSE("GPL v2");