1 files changed, 247 insertions, 0 deletions
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
new file mode 100644
index 000000000..e505b9130
--- /dev/null
+++ b/drivers/iommu/of_iommu.c
@@ -0,0 +1,247 @@
+// 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
+
+/**
+ * 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 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);
+
+		fwspec = dev_iommu_fwspec_get(dev);
+		if (!err && fwspec)
+			of_property_read_u32(master_np, "pasid-num-bits",
+					     &fwspec->num_pasid_bits);
+	}
+
+	/*
+	 * 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;
+}