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/slab.h> 26 27 static const struct of_device_id __iommu_of_table_sentinel 28 __used __section(__iommu_of_table_end); 29 30 /** 31 * of_get_dma_window - Parse *dma-window property and returns 0 if found. 32 * 33 * @dn: device node 34 * @prefix: prefix for property name if any 35 * @index: index to start to parse 36 * @busno: Returns busno if supported. Otherwise pass NULL 37 * @addr: Returns address that DMA starts 38 * @size: Returns the range that DMA can handle 39 * 40 * This supports different formats flexibly. "prefix" can be 41 * configured if any. "busno" and "index" are optionally 42 * specified. Set 0(or NULL) if not used. 43 */ 44 int of_get_dma_window(struct device_node *dn, const char *prefix, int index, 45 unsigned long *busno, dma_addr_t *addr, size_t *size) 46 { 47 const __be32 *dma_window, *end; 48 int bytes, cur_index = 0; 49 char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX]; 50 51 if (!dn || !addr || !size) 52 return -EINVAL; 53 54 if (!prefix) 55 prefix = ""; 56 57 snprintf(propname, sizeof(propname), "%sdma-window", prefix); 58 snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix); 59 snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix); 60 61 dma_window = of_get_property(dn, propname, &bytes); 62 if (!dma_window) 63 return -ENODEV; 64 end = dma_window + bytes / sizeof(*dma_window); 65 66 while (dma_window < end) { 67 u32 cells; 68 const void *prop; 69 70 /* busno is one cell if supported */ 71 if (busno) 72 *busno = be32_to_cpup(dma_window++); 73 74 prop = of_get_property(dn, addrname, NULL); 75 if (!prop) 76 prop = of_get_property(dn, "#address-cells", NULL); 77 78 cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn); 79 if (!cells) 80 return -EINVAL; 81 *addr = of_read_number(dma_window, cells); 82 dma_window += cells; 83 84 prop = of_get_property(dn, sizename, NULL); 85 cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn); 86 if (!cells) 87 return -EINVAL; 88 *size = of_read_number(dma_window, cells); 89 dma_window += cells; 90 91 if (cur_index++ == index) 92 break; 93 } 94 return 0; 95 } 96 EXPORT_SYMBOL_GPL(of_get_dma_window); 97 98 struct of_iommu_node { 99 struct list_head list; 100 struct device_node *np; 101 const struct iommu_ops *ops; 102 }; 103 static LIST_HEAD(of_iommu_list); 104 static DEFINE_SPINLOCK(of_iommu_lock); 105 106 void of_iommu_set_ops(struct device_node *np, const struct iommu_ops *ops) 107 { 108 struct of_iommu_node *iommu = kzalloc(sizeof(*iommu), GFP_KERNEL); 109 110 if (WARN_ON(!iommu)) 111 return; 112 113 of_node_get(np); 114 INIT_LIST_HEAD(&iommu->list); 115 iommu->np = np; 116 iommu->ops = ops; 117 spin_lock(&of_iommu_lock); 118 list_add_tail(&iommu->list, &of_iommu_list); 119 spin_unlock(&of_iommu_lock); 120 } 121 122 const struct iommu_ops *of_iommu_get_ops(struct device_node *np) 123 { 124 struct of_iommu_node *node; 125 const struct iommu_ops *ops = NULL; 126 127 spin_lock(&of_iommu_lock); 128 list_for_each_entry(node, &of_iommu_list, list) 129 if (node->np == np) { 130 ops = node->ops; 131 break; 132 } 133 spin_unlock(&of_iommu_lock); 134 return ops; 135 } 136 137 const struct iommu_ops *of_iommu_configure(struct device *dev, 138 struct device_node *master_np) 139 { 140 struct of_phandle_args iommu_spec; 141 struct device_node *np; 142 const struct iommu_ops *ops = NULL; 143 int idx = 0; 144 145 /* 146 * We can't do much for PCI devices without knowing how 147 * device IDs are wired up from the PCI bus to the IOMMU. 148 */ 149 if (dev_is_pci(dev)) 150 return NULL; 151 152 /* 153 * We don't currently walk up the tree looking for a parent IOMMU. 154 * See the `Notes:' section of 155 * Documentation/devicetree/bindings/iommu/iommu.txt 156 */ 157 while (!of_parse_phandle_with_args(master_np, "iommus", 158 "#iommu-cells", idx, 159 &iommu_spec)) { 160 np = iommu_spec.np; 161 ops = of_iommu_get_ops(np); 162 163 if (!ops || !ops->of_xlate || ops->of_xlate(dev, &iommu_spec)) 164 goto err_put_node; 165 166 of_node_put(np); 167 idx++; 168 } 169 170 return ops; 171 172 err_put_node: 173 of_node_put(np); 174 return NULL; 175 } 176 177 void __init of_iommu_init(void) 178 { 179 struct device_node *np; 180 const struct of_device_id *match, *matches = &__iommu_of_table; 181 182 for_each_matching_node_and_match(np, matches, &match) { 183 const of_iommu_init_fn init_fn = match->data; 184 185 if (init_fn(np)) 186 pr_err("Failed to initialise IOMMU %s\n", 187 of_node_full_name(np)); 188 } 189 } 190