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// 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/msi.h>
#include <linux/of.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 && !device_iommu_mapped(dev))
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;
}
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