drivers/iommu/of_iommu.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * OF helpers for IOMMU
  *
  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
  */

 #include <linux/export.h>
 #include <linux/iommu.h>
 #include <linux/limits.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_iommu.h>
 #include <linux/of_pci.h>
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/fsl/mc.h>

 #define NO_IOMMU	1

 static int of_iommu_xlate(struct device *dev,
 			  struct of_phandle_args *iommu_spec)
 {
 	const struct iommu_ops *ops;
 	struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
 	int ret;

 	ops = iommu_ops_from_fwnode(fwnode);
 	if ((ops && !ops->of_xlate) ||
 	    !of_device_is_available(iommu_spec->np))
 		return NO_IOMMU;

 	ret = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
 	if (ret)
 		return ret;
 	/*
 	 * The otherwise-empty fwspec handily serves to indicate the specific
 	 * IOMMU device we're waiting for, which will be useful if we ever get
 	 * a proper probe-ordering dependency mechanism in future.
 	 */
 	if (!ops)
 		return driver_deferred_probe_check_state(dev);

 	if (!try_module_get(ops->owner))
 		return -ENODEV;

 	ret = ops->of_xlate(dev, iommu_spec);
 	module_put(ops->owner);
 	return ret;
 }

 static int of_iommu_configure_dev_id(struct device_node *master_np,
 				     struct device *dev,
 				     const u32 *id)
 {
 	struct of_phandle_args iommu_spec = { .args_count = 1 };
 	int err;

 	err = of_map_id(master_np, *id, "iommu-map",
 			 "iommu-map-mask", &iommu_spec.np,
 			 iommu_spec.args);
 	if (err)
 		return err == -ENODEV ? NO_IOMMU : err;

 	err = of_iommu_xlate(dev, &iommu_spec);
 	of_node_put(iommu_spec.np);
 	return err;
 }

 static int of_iommu_configure_dev(struct device_node *master_np,
 				  struct device *dev)
 {
 	struct of_phandle_args iommu_spec;
 	int err = NO_IOMMU, idx = 0;

 	while (!of_parse_phandle_with_args(master_np, "iommus",
 					   "#iommu-cells",
 					   idx, &iommu_spec)) {
 		err = of_iommu_xlate(dev, &iommu_spec);
 		of_node_put(iommu_spec.np);
 		idx++;
 		if (err)
 			break;
 	}

 	return err;
 }

 struct of_pci_iommu_alias_info {
 	struct device *dev;
 	struct device_node *np;
 };

 static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
 {
 	struct of_pci_iommu_alias_info *info = data;
 	u32 input_id = alias;

 	return of_iommu_configure_dev_id(info->np, info->dev, &input_id);
 }

 static int of_iommu_configure_device(struct device_node *master_np,
 				     struct device *dev, const u32 *id)
 {
 	return (id) ? of_iommu_configure_dev_id(master_np, dev, id) :
 		      of_iommu_configure_dev(master_np, dev);
 }

 const struct iommu_ops *of_iommu_configure(struct device *dev,
 					   struct device_node *master_np,
 					   const u32 *id)
 {
 	const struct iommu_ops *ops = NULL;
 	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
 	int err = NO_IOMMU;

 	if (!master_np)
 		return NULL;

 	if (fwspec) {
 		if (fwspec->ops)
 			return fwspec->ops;

 		/* In the deferred case, start again from scratch */
 		iommu_fwspec_free(dev);
 	}

 	/*
 	 * We don't currently walk up the tree looking for a parent IOMMU.
 	 * See the `Notes:' section of
 	 * Documentation/devicetree/bindings/iommu/iommu.txt
 	 */
 	if (dev_is_pci(dev)) {
 		struct of_pci_iommu_alias_info info = {
 			.dev = dev,
 			.np = master_np,
 		};

 		pci_request_acs();
 		err = pci_for_each_dma_alias(to_pci_dev(dev),
 					     of_pci_iommu_init, &info);
 	} else {
 		err = of_iommu_configure_device(master_np, dev, id);
 	}

 	/*
 	 * Two success conditions can be represented by non-negative err here:
 	 * >0 : there is no IOMMU, or one was unavailable for non-fatal reasons
 	 *  0 : we found an IOMMU, and dev->fwspec is initialised appropriately
 	 * <0 : any actual error
 	 */
 	if (!err) {
 		/* The fwspec pointer changed, read it again */
 		fwspec = dev_iommu_fwspec_get(dev);
 		ops    = fwspec->ops;
 	}
 	/*
 	 * If we have reason to believe the IOMMU driver missed the initial
 	 * probe for dev, replay it to get things in order.
 	 */
 	if (!err && dev->bus)
 		err = iommu_probe_device(dev);

 	/* Ignore all other errors apart from EPROBE_DEFER */
 	if (err == -EPROBE_DEFER) {
 		ops = ERR_PTR(err);
 	} else if (err < 0) {
 		dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
 		ops = NULL;
 	}

 	return ops;
 }

 static enum iommu_resv_type __maybe_unused
 iommu_resv_region_get_type(struct device *dev,
 			   struct resource *phys,
 			   phys_addr_t start, size_t length)
 {
 	phys_addr_t end = start + length - 1;

 	/*
 	 * IOMMU regions without an associated physical region cannot be
 	 * mapped and are simply reservations.
 	 */
 	if (phys->start >= phys->end)
 		return IOMMU_RESV_RESERVED;

 	/* may be IOMMU_RESV_DIRECT_RELAXABLE for certain cases */
 	if (start == phys->start && end == phys->end)
 		return IOMMU_RESV_DIRECT;

 	dev_warn(dev, "treating non-direct mapping [%pr] -> [%pap-%pap] as reservation\n", &phys,
 		 &start, &end);
 	return IOMMU_RESV_RESERVED;
 }

 /**
  * of_iommu_get_resv_regions - reserved region driver helper for device tree
  * @dev: device for which to get reserved regions
  * @list: reserved region list
  *
  * IOMMU drivers can use this to implement their .get_resv_regions() callback
  * for memory regions attached to a device tree node. See the reserved-memory
  * device tree bindings on how to use these:
  *
  *   Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
  */
 void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
 {
 #if IS_ENABLED(CONFIG_OF_ADDRESS)
 	struct of_phandle_iterator it;
 	int err;

 	of_for_each_phandle(&it, err, dev->of_node, "memory-region", NULL, 0) {
 		const __be32 *maps, *end;
 		struct resource phys;
 		int size;

 		memset(&phys, 0, sizeof(phys));

 		/*
 		 * The "reg" property is optional and can be omitted by reserved-memory regions
 		 * that represent reservations in the IOVA space, which are regions that should
 		 * not be mapped.
 		 */
 		if (of_find_property(it.node, "reg", NULL)) {
 			err = of_address_to_resource(it.node, 0, &phys);
 			if (err < 0) {
 				dev_err(dev, "failed to parse memory region %pOF: %d\n",
 					it.node, err);
 				continue;
 			}
 		}

 		maps = of_get_property(it.node, "iommu-addresses", &size);
 		if (!maps)
 			continue;

 		end = maps + size / sizeof(__be32);

 		while (maps < end) {
 			struct device_node *np;
 			u32 phandle;

 			phandle = be32_to_cpup(maps++);
 			np = of_find_node_by_phandle(phandle);

 			if (np == dev->of_node) {
 				int prot = IOMMU_READ | IOMMU_WRITE;
 				struct iommu_resv_region *region;
 				enum iommu_resv_type type;
 				phys_addr_t iova;
 				size_t length;

 				maps = of_translate_dma_region(np, maps, &iova, &length);
 				type = iommu_resv_region_get_type(dev, &phys, iova, length);

 				region = iommu_alloc_resv_region(iova, length, prot, type,
 								 GFP_KERNEL);
 				if (region)
 					list_add_tail(&region->list, list);
 			}
 		}
 	}
 #endif
 }
 EXPORT_SYMBOL(of_iommu_get_resv_regions);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* OF helpers for IOMMU
	*
	* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
	*/

	#include <linux/export.h>
	#include <linux/iommu.h>
	#include <linux/limits.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/of_iommu.h>
	#include <linux/of_pci.h>
	#include <linux/pci.h>
	#include <linux/slab.h>
	#include <linux/fsl/mc.h>

	#define NO_IOMMU 1

	static int of_iommu_xlate(struct device *dev,
	struct of_phandle_args *iommu_spec)
	{
	const struct iommu_ops *ops;
	struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
	int ret;

	ops = iommu_ops_from_fwnode(fwnode);
	if ((ops && !ops->of_xlate) \|\|
	!of_device_is_available(iommu_spec->np))
	return NO_IOMMU;

	ret = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
	if (ret)
	return ret;
	/*
	* The otherwise-empty fwspec handily serves to indicate the specific
	* IOMMU device we're waiting for, which will be useful if we ever get
	* a proper probe-ordering dependency mechanism in future.
	*/
	if (!ops)
	return driver_deferred_probe_check_state(dev);

	if (!try_module_get(ops->owner))
	return -ENODEV;

	ret = ops->of_xlate(dev, iommu_spec);
	module_put(ops->owner);
	return ret;
	}

	static int of_iommu_configure_dev_id(struct device_node *master_np,
	struct device *dev,
	const u32 *id)
	{
	struct of_phandle_args iommu_spec = { .args_count = 1 };
	int err;

	err = of_map_id(master_np, *id, "iommu-map",
	"iommu-map-mask", &iommu_spec.np,
	iommu_spec.args);
	if (err)
	return err == -ENODEV ? NO_IOMMU : err;

	err = of_iommu_xlate(dev, &iommu_spec);
	of_node_put(iommu_spec.np);
	return err;
	}

	static int of_iommu_configure_dev(struct device_node *master_np,
	struct device *dev)
	{
	struct of_phandle_args iommu_spec;
	int err = NO_IOMMU, idx = 0;

	while (!of_parse_phandle_with_args(master_np, "iommus",
	"#iommu-cells",
	idx, &iommu_spec)) {
	err = of_iommu_xlate(dev, &iommu_spec);
	of_node_put(iommu_spec.np);
	idx++;
	if (err)
	break;
	}

	return err;
	}

	struct of_pci_iommu_alias_info {
	struct device *dev;
	struct device_node *np;
	};

	static int of_pci_iommu_init(struct pci_dev pdev, u16 alias, void data)
	{
	struct of_pci_iommu_alias_info *info = data;
	u32 input_id = alias;

	return of_iommu_configure_dev_id(info->np, info->dev, &input_id);
	}

	static int of_iommu_configure_device(struct device_node *master_np,
	struct device dev, const u32 id)
	{
	return (id) ? of_iommu_configure_dev_id(master_np, dev, id) :
	of_iommu_configure_dev(master_np, dev);
	}

	const struct iommu_ops of_iommu_configure(struct device dev,
	struct device_node *master_np,
	const u32 *id)
	{
	const struct iommu_ops *ops = NULL;
	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
	int err = NO_IOMMU;

	if (!master_np)
	return NULL;

	if (fwspec) {
	if (fwspec->ops)
	return fwspec->ops;

	/* In the deferred case, start again from scratch */
	iommu_fwspec_free(dev);
	}

	/*
	* We don't currently walk up the tree looking for a parent IOMMU.
	* See the `Notes:' section of
	* Documentation/devicetree/bindings/iommu/iommu.txt
	*/
	if (dev_is_pci(dev)) {
	struct of_pci_iommu_alias_info info = {
	.dev = dev,
	.np = master_np,
	};

	pci_request_acs();
	err = pci_for_each_dma_alias(to_pci_dev(dev),
	of_pci_iommu_init, &info);
	} else {
	err = of_iommu_configure_device(master_np, dev, id);
	}

	/*
	* Two success conditions can be represented by non-negative err here:
	* >0 : there is no IOMMU, or one was unavailable for non-fatal reasons
	* 0 : we found an IOMMU, and dev->fwspec is initialised appropriately
	* <0 : any actual error
	*/
	if (!err) {
	/* The fwspec pointer changed, read it again */
	fwspec = dev_iommu_fwspec_get(dev);
	ops = fwspec->ops;
	}
	/*
	* If we have reason to believe the IOMMU driver missed the initial
	* probe for dev, replay it to get things in order.
	*/
	if (!err && dev->bus)
	err = iommu_probe_device(dev);

	/* Ignore all other errors apart from EPROBE_DEFER */
	if (err == -EPROBE_DEFER) {
	ops = ERR_PTR(err);
	} else if (err < 0) {
	dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
	ops = NULL;
	}

	return ops;
	}

	static enum iommu_resv_type __maybe_unused
	iommu_resv_region_get_type(struct device *dev,
	struct resource *phys,
	phys_addr_t start, size_t length)
	{
	phys_addr_t end = start + length - 1;

	/*
	* IOMMU regions without an associated physical region cannot be
	* mapped and are simply reservations.
	*/
	if (phys->start >= phys->end)
	return IOMMU_RESV_RESERVED;

	/* may be IOMMU_RESV_DIRECT_RELAXABLE for certain cases */
	if (start == phys->start && end == phys->end)
	return IOMMU_RESV_DIRECT;

	dev_warn(dev, "treating non-direct mapping [%pr] -> [%pap-%pap] as reservation\n", &phys,
	&start, &end);
	return IOMMU_RESV_RESERVED;
	}

	/**
	* of_iommu_get_resv_regions - reserved region driver helper for device tree
	* @dev: device for which to get reserved regions
	* @list: reserved region list
	*
	* IOMMU drivers can use this to implement their .get_resv_regions() callback
	* for memory regions attached to a device tree node. See the reserved-memory
	* device tree bindings on how to use these:
	*
	* Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
	*/
	void of_iommu_get_resv_regions(struct device dev, struct list_head list)
	{
	#if IS_ENABLED(CONFIG_OF_ADDRESS)
	struct of_phandle_iterator it;
	int err;

	of_for_each_phandle(&it, err, dev->of_node, "memory-region", NULL, 0) {
	const __be32 maps, end;
	struct resource phys;
	int size;

	memset(&phys, 0, sizeof(phys));

	/*
	* The "reg" property is optional and can be omitted by reserved-memory regions
	* that represent reservations in the IOVA space, which are regions that should
	* not be mapped.
	*/
	if (of_find_property(it.node, "reg", NULL)) {
	err = of_address_to_resource(it.node, 0, &phys);
	if (err < 0) {
	dev_err(dev, "failed to parse memory region %pOF: %d\n",
	it.node, err);
	continue;
	}
	}

	maps = of_get_property(it.node, "iommu-addresses", &size);
	if (!maps)
	continue;

	end = maps + size / sizeof(__be32);

	while (maps < end) {
	struct device_node *np;
	u32 phandle;

	phandle = be32_to_cpup(maps++);
	np = of_find_node_by_phandle(phandle);

	if (np == dev->of_node) {
	int prot = IOMMU_READ \| IOMMU_WRITE;
	struct iommu_resv_region *region;
	enum iommu_resv_type type;
	phys_addr_t iova;
	size_t length;

	maps = of_translate_dma_region(np, maps, &iova, &length);
	type = iommu_resv_region_get_type(dev, &phys, iova, length);

	region = iommu_alloc_resv_region(iova, length, prot, type,
	GFP_KERNEL);
	if (region)
	list_add_tail(&region->list, list);
	}
	}
	}
	#endif
	}
	EXPORT_SYMBOL(of_iommu_get_resv_regions);