1 /* 2 * Routines for tracking a legacy ISA bridge 3 * 4 * Copyrigh 2007 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp. 5 * 6 * Some bits and pieces moved over from pci_64.c 7 * 8 * Copyrigh 2003 Anton Blanchard <anton@au.ibm.com>, IBM Corp. 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 */ 15 16 #define DEBUG 17 18 #include <linux/kernel.h> 19 #include <linux/pci.h> 20 #include <linux/string.h> 21 #include <linux/export.h> 22 #include <linux/init.h> 23 #include <linux/mm.h> 24 #include <linux/notifier.h> 25 26 #include <asm/processor.h> 27 #include <asm/io.h> 28 #include <asm/prom.h> 29 #include <asm/pci-bridge.h> 30 #include <asm/machdep.h> 31 #include <asm/ppc-pci.h> 32 33 unsigned long isa_io_base; /* NULL if no ISA bus */ 34 EXPORT_SYMBOL(isa_io_base); 35 36 /* Cached ISA bridge dev. */ 37 static struct device_node *isa_bridge_devnode; 38 struct pci_dev *isa_bridge_pcidev; 39 EXPORT_SYMBOL_GPL(isa_bridge_pcidev); 40 41 #define ISA_SPACE_MASK 0x1 42 #define ISA_SPACE_IO 0x1 43 44 static void pci_process_ISA_OF_ranges(struct device_node *isa_node, 45 unsigned long phb_io_base_phys) 46 { 47 /* We should get some saner parsing here and remove these structs */ 48 struct pci_address { 49 u32 a_hi; 50 u32 a_mid; 51 u32 a_lo; 52 }; 53 54 struct isa_address { 55 u32 a_hi; 56 u32 a_lo; 57 }; 58 59 struct isa_range { 60 struct isa_address isa_addr; 61 struct pci_address pci_addr; 62 unsigned int size; 63 }; 64 65 const struct isa_range *range; 66 unsigned long pci_addr; 67 unsigned int isa_addr; 68 unsigned int size; 69 int rlen = 0; 70 71 range = of_get_property(isa_node, "ranges", &rlen); 72 if (range == NULL || (rlen < sizeof(struct isa_range))) 73 goto inval_range; 74 75 /* From "ISA Binding to 1275" 76 * The ranges property is laid out as an array of elements, 77 * each of which comprises: 78 * cells 0 - 1: an ISA address 79 * cells 2 - 4: a PCI address 80 * (size depending on dev->n_addr_cells) 81 * cell 5: the size of the range 82 */ 83 if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO) { 84 range++; 85 rlen -= sizeof(struct isa_range); 86 if (rlen < sizeof(struct isa_range)) 87 goto inval_range; 88 } 89 if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO) 90 goto inval_range; 91 92 isa_addr = range->isa_addr.a_lo; 93 pci_addr = (unsigned long) range->pci_addr.a_mid << 32 | 94 range->pci_addr.a_lo; 95 96 /* Assume these are both zero. Note: We could fix that and 97 * do a proper parsing instead ... oh well, that will do for 98 * now as nobody uses fancy mappings for ISA bridges 99 */ 100 if ((pci_addr != 0) || (isa_addr != 0)) { 101 printk(KERN_ERR "unexpected isa to pci mapping: %s\n", 102 __func__); 103 return; 104 } 105 106 /* Align size and make sure it's cropped to 64K */ 107 size = PAGE_ALIGN(range->size); 108 if (size > 0x10000) 109 size = 0x10000; 110 111 __ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE, 112 size, _PAGE_NO_CACHE|_PAGE_GUARDED); 113 return; 114 115 inval_range: 116 printk(KERN_ERR "no ISA IO ranges or unexpected isa range, " 117 "mapping 64k\n"); 118 __ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE, 119 0x10000, _PAGE_NO_CACHE|_PAGE_GUARDED); 120 } 121 122 123 /** 124 * isa_bridge_find_early - Find and map the ISA IO space early before 125 * main PCI discovery. This is optionally called by 126 * the arch code when adding PCI PHBs to get early 127 * access to ISA IO ports 128 */ 129 void __init isa_bridge_find_early(struct pci_controller *hose) 130 { 131 struct device_node *np, *parent = NULL, *tmp; 132 133 /* If we already have an ISA bridge, bail off */ 134 if (isa_bridge_devnode != NULL) 135 return; 136 137 /* For each "isa" node in the system. Note : we do a search by 138 * type and not by name. It might be better to do by name but that's 139 * what the code used to do and I don't want to break too much at 140 * once. We can look into changing that separately 141 */ 142 for_each_node_by_type(np, "isa") { 143 /* Look for our hose being a parent */ 144 for (parent = of_get_parent(np); parent;) { 145 if (parent == hose->dn) { 146 of_node_put(parent); 147 break; 148 } 149 tmp = parent; 150 parent = of_get_parent(parent); 151 of_node_put(tmp); 152 } 153 if (parent != NULL) 154 break; 155 } 156 if (np == NULL) 157 return; 158 isa_bridge_devnode = np; 159 160 /* Now parse the "ranges" property and setup the ISA mapping */ 161 pci_process_ISA_OF_ranges(np, hose->io_base_phys); 162 163 /* Set the global ISA io base to indicate we have an ISA bridge */ 164 isa_io_base = ISA_IO_BASE; 165 166 pr_debug("ISA bridge (early) is %s\n", np->full_name); 167 } 168 169 /** 170 * isa_bridge_find_late - Find and map the ISA IO space upon discovery of 171 * a new ISA bridge 172 */ 173 static void isa_bridge_find_late(struct pci_dev *pdev, 174 struct device_node *devnode) 175 { 176 struct pci_controller *hose = pci_bus_to_host(pdev->bus); 177 178 /* Store ISA device node and PCI device */ 179 isa_bridge_devnode = of_node_get(devnode); 180 isa_bridge_pcidev = pdev; 181 182 /* Now parse the "ranges" property and setup the ISA mapping */ 183 pci_process_ISA_OF_ranges(devnode, hose->io_base_phys); 184 185 /* Set the global ISA io base to indicate we have an ISA bridge */ 186 isa_io_base = ISA_IO_BASE; 187 188 pr_debug("ISA bridge (late) is %s on %s\n", 189 devnode->full_name, pci_name(pdev)); 190 } 191 192 /** 193 * isa_bridge_remove - Remove/unmap an ISA bridge 194 */ 195 static void isa_bridge_remove(void) 196 { 197 pr_debug("ISA bridge removed !\n"); 198 199 /* Clear the global ISA io base to indicate that we have no more 200 * ISA bridge. Note that drivers don't quite handle that, though 201 * we should probably do something about it. But do we ever really 202 * have ISA bridges being removed on machines using legacy devices ? 203 */ 204 isa_io_base = ISA_IO_BASE; 205 206 /* Clear references to the bridge */ 207 of_node_put(isa_bridge_devnode); 208 isa_bridge_devnode = NULL; 209 isa_bridge_pcidev = NULL; 210 211 /* Unmap the ISA area */ 212 __iounmap_at((void *)ISA_IO_BASE, 0x10000); 213 } 214 215 /** 216 * isa_bridge_notify - Get notified of PCI devices addition/removal 217 */ 218 static int isa_bridge_notify(struct notifier_block *nb, unsigned long action, 219 void *data) 220 { 221 struct device *dev = data; 222 struct pci_dev *pdev = to_pci_dev(dev); 223 struct device_node *devnode = pci_device_to_OF_node(pdev); 224 225 switch(action) { 226 case BUS_NOTIFY_ADD_DEVICE: 227 /* Check if we have an early ISA device, without PCI dev */ 228 if (isa_bridge_devnode && isa_bridge_devnode == devnode && 229 !isa_bridge_pcidev) { 230 pr_debug("ISA bridge PCI attached: %s\n", 231 pci_name(pdev)); 232 isa_bridge_pcidev = pdev; 233 } 234 235 /* Check if we have no ISA device, and this happens to be one, 236 * register it as such if it has an OF device 237 */ 238 if (!isa_bridge_devnode && devnode && devnode->type && 239 !strcmp(devnode->type, "isa")) 240 isa_bridge_find_late(pdev, devnode); 241 242 return 0; 243 case BUS_NOTIFY_DEL_DEVICE: 244 /* Check if this our existing ISA device */ 245 if (pdev == isa_bridge_pcidev || 246 (devnode && devnode == isa_bridge_devnode)) 247 isa_bridge_remove(); 248 return 0; 249 } 250 return 0; 251 } 252 253 static struct notifier_block isa_bridge_notifier = { 254 .notifier_call = isa_bridge_notify 255 }; 256 257 /** 258 * isa_bridge_init - register to be notified of ISA bridge addition/removal 259 * 260 */ 261 static int __init isa_bridge_init(void) 262 { 263 bus_register_notifier(&pci_bus_type, &isa_bridge_notifier); 264 return 0; 265 } 266 arch_initcall(isa_bridge_init); 267