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

 /*
  * OF helpers for IOMMU
  *
  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  */

 #include <linux/export.h>
 #include <linux/iommu.h>
 #include <linux/limits.h>
 #include <linux/of.h>
 #include <linux/of_iommu.h>
 #include <linux/of_pci.h>
 #include <linux/slab.h>

 static const struct of_device_id __iommu_of_table_sentinel
 	__used __section(__iommu_of_table_end);

 /**
  * of_get_dma_window - Parse *dma-window property and returns 0 if found.
  *
  * @dn: device node
  * @prefix: prefix for property name if any
  * @index: index to start to parse
  * @busno: Returns busno if supported. Otherwise pass NULL
  * @addr: Returns address that DMA starts
  * @size: Returns the range that DMA can handle
  *
  * This supports different formats flexibly. "prefix" can be
  * configured if any. "busno" and "index" are optionally
  * specified. Set 0(or NULL) if not used.
  */
 int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
 		      unsigned long *busno, dma_addr_t *addr, size_t *size)
 {
 	const __be32 *dma_window, *end;
 	int bytes, cur_index = 0;
 	char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX];

 	if (!dn || !addr || !size)
 		return -EINVAL;

 	if (!prefix)
 		prefix = "";

 	snprintf(propname, sizeof(propname), "%sdma-window", prefix);
 	snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix);
 	snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix);

 	dma_window = of_get_property(dn, propname, &bytes);
 	if (!dma_window)
 		return -ENODEV;
 	end = dma_window + bytes / sizeof(*dma_window);

 	while (dma_window < end) {
 		u32 cells;
 		const void *prop;

 		/* busno is one cell if supported */
 		if (busno)
 			*busno = be32_to_cpup(dma_window++);

 		prop = of_get_property(dn, addrname, NULL);
 		if (!prop)
 			prop = of_get_property(dn, "#address-cells", NULL);

 		cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn);
 		if (!cells)
 			return -EINVAL;
 		*addr = of_read_number(dma_window, cells);
 		dma_window += cells;

 		prop = of_get_property(dn, sizename, NULL);
 		cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn);
 		if (!cells)
 			return -EINVAL;
 		*size = of_read_number(dma_window, cells);
 		dma_window += cells;

 		if (cur_index++ == index)
 			break;
 	}
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_get_dma_window);

 static bool of_iommu_driver_present(struct device_node *np)
 {
 	/*
 	 * If the IOMMU still isn't ready by the time we reach init, assume
 	 * it never will be. We don't want to defer indefinitely, nor attempt
 	 * to dereference __iommu_of_table after it's been freed.
 	 */
 	if (system_state > SYSTEM_BOOTING)
 		return false;

 	return of_match_node(&__iommu_of_table, np);
 }

 static const struct iommu_ops
 *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 err;

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

 	err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
 	if (err)
 		return ERR_PTR(err);
 	/*
 	 * 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 ERR_PTR(-EPROBE_DEFER);

 	err = ops->of_xlate(dev, iommu_spec);
 	if (err)
 		return ERR_PTR(err);

 	return ops;
 }

 static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
 {
 	struct of_phandle_args *iommu_spec = data;

 	iommu_spec->args[0] = alias;
 	return iommu_spec->np == pdev->bus->dev.of_node;
 }

 static const struct iommu_ops
 *of_pci_iommu_init(struct pci_dev *pdev, struct device_node *bridge_np)
 {
 	const struct iommu_ops *ops;
 	struct of_phandle_args iommu_spec;
 	int err;

 	/*
 	 * Start by tracing the RID alias down the PCI topology as
 	 * far as the host bridge whose OF node we have...
 	 * (we're not even attempting to handle multi-alias devices yet)
 	 */
 	iommu_spec.args_count = 1;
 	iommu_spec.np = bridge_np;
 	pci_for_each_dma_alias(pdev, __get_pci_rid, &iommu_spec);
 	/*
 	 * ...then find out what that becomes once it escapes the PCI
 	 * bus into the system beyond, and which IOMMU it ends up at.
 	 */
 	iommu_spec.np = NULL;
 	err = of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map",
 			     "iommu-map-mask", &iommu_spec.np,
 			     iommu_spec.args);
 	if (err)
 		return err == -ENODEV ? NULL : ERR_PTR(err);

 	ops = of_iommu_xlate(&pdev->dev, &iommu_spec);

 	of_node_put(iommu_spec.np);
 	return ops;
 }

 static const struct iommu_ops
 *of_platform_iommu_init(struct device *dev, struct device_node *np)
 {
 	struct of_phandle_args iommu_spec;
 	const struct iommu_ops *ops = NULL;
 	int idx = 0;

 	/*
 	 * We don't currently walk up the tree looking for a parent IOMMU.
 	 * See the `Notes:' section of
 	 * Documentation/devicetree/bindings/iommu/iommu.txt
 	 */
 	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells",
 					   idx, &iommu_spec)) {
 		ops = of_iommu_xlate(dev, &iommu_spec);
 		of_node_put(iommu_spec.np);
 		idx++;
 		if (IS_ERR_OR_NULL(ops))
 			break;
 	}

 	return ops;
 }

 const struct iommu_ops *of_iommu_configure(struct device *dev,
 					   struct device_node *master_np)
 {
 	const struct iommu_ops *ops;
 	struct iommu_fwspec *fwspec = dev->iommu_fwspec;

 	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);
 	}

 	if (dev_is_pci(dev))
 		ops = of_pci_iommu_init(to_pci_dev(dev), master_np);
 	else
 		ops = of_platform_iommu_init(dev, master_np);
 	/*
 	 * If we have reason to believe the IOMMU driver missed the initial
 	 * add_device callback for dev, replay it to get things in order.
 	 */
 	if (!IS_ERR_OR_NULL(ops) && ops->add_device &&
 	    dev->bus && !dev->iommu_group) {
 		int err = ops->add_device(dev);

 		if (err)
 			ops = ERR_PTR(err);
 	}

 	/* Ignore all other errors apart from EPROBE_DEFER */
 	if (IS_ERR(ops) && (PTR_ERR(ops) != -EPROBE_DEFER)) {
 		dev_dbg(dev, "Adding to IOMMU failed: %ld\n", PTR_ERR(ops));
 		ops = NULL;
 	}

 	return ops;
 }

 static int __init of_iommu_init(void)
 {
 	struct device_node *np;
 	const struct of_device_id *match, *matches = &__iommu_of_table;

 	for_each_matching_node_and_match(np, matches, &match) {
 		const of_iommu_init_fn init_fn = match->data;

 		if (init_fn && init_fn(np))
 			pr_err("Failed to initialise IOMMU %s\n",
 				of_node_full_name(np));
 	}

 	return 0;
 }
 postcore_initcall_sync(of_iommu_init);
	/*
	* OF helpers for IOMMU
	*
	* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program; if not, write to the Free Software Foundation, Inc.,
	* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
	*/

	#include <linux/export.h>
	#include <linux/iommu.h>
	#include <linux/limits.h>
	#include <linux/of.h>
	#include <linux/of_iommu.h>
	#include <linux/of_pci.h>
	#include <linux/slab.h>

	static const struct of_device_id __iommu_of_table_sentinel
	__used __section(__iommu_of_table_end);

	/**
	* of_get_dma_window - Parse *dma-window property and returns 0 if found.
	*
	* @dn: device node
	* @prefix: prefix for property name if any
	* @index: index to start to parse
	* @busno: Returns busno if supported. Otherwise pass NULL
	* @addr: Returns address that DMA starts
	* @size: Returns the range that DMA can handle
	*
	* This supports different formats flexibly. "prefix" can be
	* configured if any. "busno" and "index" are optionally
	* specified. Set 0(or NULL) if not used.
	*/
	int of_get_dma_window(struct device_node dn, const char prefix, int index,
	unsigned long busno, dma_addr_t addr, size_t *size)
	{
	const __be32 dma_window, end;
	int bytes, cur_index = 0;
	char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX];

	if (!dn \|\| !addr \|\| !size)
	return -EINVAL;

	if (!prefix)
	prefix = "";

	snprintf(propname, sizeof(propname), "%sdma-window", prefix);
	snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix);
	snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix);

	dma_window = of_get_property(dn, propname, &bytes);
	if (!dma_window)
	return -ENODEV;
	end = dma_window + bytes / sizeof(*dma_window);

	while (dma_window < end) {
	u32 cells;
	const void *prop;

	/* busno is one cell if supported */
	if (busno)
	*busno = be32_to_cpup(dma_window++);

	prop = of_get_property(dn, addrname, NULL);
	if (!prop)
	prop = of_get_property(dn, "#address-cells", NULL);

	cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn);
	if (!cells)
	return -EINVAL;
	*addr = of_read_number(dma_window, cells);
	dma_window += cells;

	prop = of_get_property(dn, sizename, NULL);
	cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn);
	if (!cells)
	return -EINVAL;
	*size = of_read_number(dma_window, cells);
	dma_window += cells;

	if (cur_index++ == index)
	break;
	}
	return 0;
	}
	EXPORT_SYMBOL_GPL(of_get_dma_window);

	static bool of_iommu_driver_present(struct device_node *np)
	{
	/*
	* If the IOMMU still isn't ready by the time we reach init, assume
	* it never will be. We don't want to defer indefinitely, nor attempt
	* to dereference __iommu_of_table after it's been freed.
	*/
	if (system_state > SYSTEM_BOOTING)
	return false;

	return of_match_node(&__iommu_of_table, np);
	}

	static const struct iommu_ops
	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 err;

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

	err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
	if (err)
	return ERR_PTR(err);
	/*
	* 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 ERR_PTR(-EPROBE_DEFER);

	err = ops->of_xlate(dev, iommu_spec);
	if (err)
	return ERR_PTR(err);

	return ops;
	}

	static int __get_pci_rid(struct pci_dev pdev, u16 alias, void data)
	{
	struct of_phandle_args *iommu_spec = data;

	iommu_spec->args[0] = alias;
	return iommu_spec->np == pdev->bus->dev.of_node;
	}

	static const struct iommu_ops
	of_pci_iommu_init(struct pci_dev pdev, struct device_node *bridge_np)
	{
	const struct iommu_ops *ops;
	struct of_phandle_args iommu_spec;
	int err;

	/*
	* Start by tracing the RID alias down the PCI topology as
	* far as the host bridge whose OF node we have...
	* (we're not even attempting to handle multi-alias devices yet)
	*/
	iommu_spec.args_count = 1;
	iommu_spec.np = bridge_np;
	pci_for_each_dma_alias(pdev, __get_pci_rid, &iommu_spec);
	/*
	* ...then find out what that becomes once it escapes the PCI
	* bus into the system beyond, and which IOMMU it ends up at.
	*/
	iommu_spec.np = NULL;
	err = of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map",
	"iommu-map-mask", &iommu_spec.np,
	iommu_spec.args);
	if (err)
	return err == -ENODEV ? NULL : ERR_PTR(err);

	ops = of_iommu_xlate(&pdev->dev, &iommu_spec);

	of_node_put(iommu_spec.np);
	return ops;
	}

	static const struct iommu_ops
	of_platform_iommu_init(struct device dev, struct device_node *np)
	{
	struct of_phandle_args iommu_spec;
	const struct iommu_ops *ops = NULL;
	int idx = 0;

	/*
	* We don't currently walk up the tree looking for a parent IOMMU.
	* See the `Notes:' section of
	* Documentation/devicetree/bindings/iommu/iommu.txt
	*/
	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells",
	idx, &iommu_spec)) {
	ops = of_iommu_xlate(dev, &iommu_spec);
	of_node_put(iommu_spec.np);
	idx++;
	if (IS_ERR_OR_NULL(ops))
	break;
	}

	return ops;
	}

	const struct iommu_ops of_iommu_configure(struct device dev,
	struct device_node *master_np)
	{
	const struct iommu_ops *ops;
	struct iommu_fwspec *fwspec = dev->iommu_fwspec;

	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);
	}

	if (dev_is_pci(dev))
	ops = of_pci_iommu_init(to_pci_dev(dev), master_np);
	else
	ops = of_platform_iommu_init(dev, master_np);
	/*
	* If we have reason to believe the IOMMU driver missed the initial
	* add_device callback for dev, replay it to get things in order.
	*/
	if (!IS_ERR_OR_NULL(ops) && ops->add_device &&
	dev->bus && !dev->iommu_group) {
	int err = ops->add_device(dev);

	if (err)
	ops = ERR_PTR(err);
	}

	/* Ignore all other errors apart from EPROBE_DEFER */
	if (IS_ERR(ops) && (PTR_ERR(ops) != -EPROBE_DEFER)) {
	dev_dbg(dev, "Adding to IOMMU failed: %ld\n", PTR_ERR(ops));
	ops = NULL;
	}

	return ops;
	}

	static int __init of_iommu_init(void)
	{
	struct device_node *np;
	const struct of_device_id match, matches = &__iommu_of_table;

	for_each_matching_node_and_match(np, matches, &match) {
	const of_iommu_init_fn init_fn = match->data;

	if (init_fn && init_fn(np))
	pr_err("Failed to initialise IOMMU %s\n",
	of_node_full_name(np));
	}

	return 0;
	}
	postcore_initcall_sync(of_iommu_init);