diff options
Diffstat (limited to 'drivers/iommu/of_iommu.c')
| -rw-r--r-- | drivers/iommu/of_iommu.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c new file mode 100644 index 000000000..1fa1db3be --- /dev/null +++ b/drivers/iommu/of_iommu.c @@ -0,0 +1,180 @@ +// 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; + int err = NO_IOMMU; + + if (!master_np) + return NULL; + + /* Serialise to make dev->iommu stable under our potential fwspec */ + mutex_lock(&iommu_probe_device_lock); + fwspec = dev_iommu_fwspec_get(dev); + if (fwspec) { + if (fwspec->ops) { + mutex_unlock(&iommu_probe_device_lock); + 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; + } + mutex_unlock(&iommu_probe_device_lock); + + /* + * 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; +} |