1 /* 2 * OF helpers for IOMMU 3 * 4 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms and conditions of the GNU General Public License, 8 * version 2, as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 13 * more details. 14 * 15 * You should have received a copy of the GNU General Public License along with 16 * this program; if not, write to the Free Software Foundation, Inc., 17 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. 18 */ 19 20 #include <linux/export.h> 21 #include <linux/iommu.h> 22 #include <linux/limits.h> 23 #include <linux/of.h> 24 #include <linux/of_iommu.h> 25 #include <linux/of_pci.h> 26 #include <linux/slab.h> 27 28 static const struct of_device_id __iommu_of_table_sentinel 29 __used __section(__iommu_of_table_end); 30 31 /** 32 * of_get_dma_window - Parse *dma-window property and returns 0 if found. 33 * 34 * @dn: device node 35 * @prefix: prefix for property name if any 36 * @index: index to start to parse 37 * @busno: Returns busno if supported. Otherwise pass NULL 38 * @addr: Returns address that DMA starts 39 * @size: Returns the range that DMA can handle 40 * 41 * This supports different formats flexibly. "prefix" can be 42 * configured if any. "busno" and "index" are optionally 43 * specified. Set 0(or NULL) if not used. 44 */ 45 int of_get_dma_window(struct device_node *dn, const char *prefix, int index, 46 unsigned long *busno, dma_addr_t *addr, size_t *size) 47 { 48 const __be32 *dma_window, *end; 49 int bytes, cur_index = 0; 50 char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX]; 51 52 if (!dn || !addr || !size) 53 return -EINVAL; 54 55 if (!prefix) 56 prefix = ""; 57 58 snprintf(propname, sizeof(propname), "%sdma-window", prefix); 59 snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix); 60 snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix); 61 62 dma_window = of_get_property(dn, propname, &bytes); 63 if (!dma_window) 64 return -ENODEV; 65 end = dma_window + bytes / sizeof(*dma_window); 66 67 while (dma_window < end) { 68 u32 cells; 69 const void *prop; 70 71 /* busno is one cell if supported */ 72 if (busno) 73 *busno = be32_to_cpup(dma_window++); 74 75 prop = of_get_property(dn, addrname, NULL); 76 if (!prop) 77 prop = of_get_property(dn, "#address-cells", NULL); 78 79 cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn); 80 if (!cells) 81 return -EINVAL; 82 *addr = of_read_number(dma_window, cells); 83 dma_window += cells; 84 85 prop = of_get_property(dn, sizename, NULL); 86 cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn); 87 if (!cells) 88 return -EINVAL; 89 *size = of_read_number(dma_window, cells); 90 dma_window += cells; 91 92 if (cur_index++ == index) 93 break; 94 } 95 return 0; 96 } 97 EXPORT_SYMBOL_GPL(of_get_dma_window); 98 99 static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data) 100 { 101 struct of_phandle_args *iommu_spec = data; 102 103 iommu_spec->args[0] = alias; 104 return iommu_spec->np == pdev->bus->dev.of_node; 105 } 106 107 static const struct iommu_ops 108 *of_pci_iommu_configure(struct pci_dev *pdev, struct device_node *bridge_np) 109 { 110 const struct iommu_ops *ops; 111 struct of_phandle_args iommu_spec; 112 113 /* 114 * Start by tracing the RID alias down the PCI topology as 115 * far as the host bridge whose OF node we have... 116 * (we're not even attempting to handle multi-alias devices yet) 117 */ 118 iommu_spec.args_count = 1; 119 iommu_spec.np = bridge_np; 120 pci_for_each_dma_alias(pdev, __get_pci_rid, &iommu_spec); 121 /* 122 * ...then find out what that becomes once it escapes the PCI 123 * bus into the system beyond, and which IOMMU it ends up at. 124 */ 125 iommu_spec.np = NULL; 126 if (of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map", 127 "iommu-map-mask", &iommu_spec.np, iommu_spec.args)) 128 return NULL; 129 130 ops = of_iommu_get_ops(iommu_spec.np); 131 if (!ops || !ops->of_xlate || 132 iommu_fwspec_init(&pdev->dev, &iommu_spec.np->fwnode, ops) || 133 ops->of_xlate(&pdev->dev, &iommu_spec)) 134 ops = NULL; 135 136 of_node_put(iommu_spec.np); 137 return ops; 138 } 139 140 const struct iommu_ops *of_iommu_configure(struct device *dev, 141 struct device_node *master_np) 142 { 143 struct of_phandle_args iommu_spec; 144 struct device_node *np; 145 const struct iommu_ops *ops = NULL; 146 int idx = 0; 147 148 if (dev_is_pci(dev)) 149 return of_pci_iommu_configure(to_pci_dev(dev), master_np); 150 151 /* 152 * We don't currently walk up the tree looking for a parent IOMMU. 153 * See the `Notes:' section of 154 * Documentation/devicetree/bindings/iommu/iommu.txt 155 */ 156 while (!of_parse_phandle_with_args(master_np, "iommus", 157 "#iommu-cells", idx, 158 &iommu_spec)) { 159 np = iommu_spec.np; 160 ops = of_iommu_get_ops(np); 161 162 if (!ops || !ops->of_xlate || 163 iommu_fwspec_init(dev, &np->fwnode, ops) || 164 ops->of_xlate(dev, &iommu_spec)) 165 goto err_put_node; 166 167 of_node_put(np); 168 idx++; 169 } 170 171 return ops; 172 173 err_put_node: 174 of_node_put(np); 175 return NULL; 176 } 177 178 static int __init of_iommu_init(void) 179 { 180 struct device_node *np; 181 const struct of_device_id *match, *matches = &__iommu_of_table; 182 183 for_each_matching_node_and_match(np, matches, &match) { 184 const of_iommu_init_fn init_fn = match->data; 185 186 if (init_fn(np)) 187 pr_err("Failed to initialise IOMMU %s\n", 188 of_node_full_name(np)); 189 } 190 191 return 0; 192 } 193 postcore_initcall_sync(of_iommu_init); 194