arch/powerpc/kernel/isa-bridge.c

   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 #include <asm/firmware.h>
  33
  34 unsigned long isa_io_base;      /* NULL if no ISA bus */
  35 EXPORT_SYMBOL(isa_io_base);
  36
  37 /* Cached ISA bridge dev. */
  38 static struct device_node *isa_bridge_devnode;
  39 struct pci_dev *isa_bridge_pcidev;
  40 EXPORT_SYMBOL_GPL(isa_bridge_pcidev);
  41
  42 #define ISA_SPACE_MASK 0x1
  43 #define ISA_SPACE_IO 0x1
  44
  45 static void __devinit pci_process_ISA_OF_ranges(struct device_node *isa_node,
  46                                                 unsigned long phb_io_base_phys)
  47 {
  48         /* We should get some saner parsing here and remove these structs */
  49         struct pci_address {
  50                 u32 a_hi;
  51                 u32 a_mid;
  52                 u32 a_lo;
  53         };
  54
  55         struct isa_address {
  56                 u32 a_hi;
  57                 u32 a_lo;
  58         };
  59
  60         struct isa_range {
  61                 struct isa_address isa_addr;
  62                 struct pci_address pci_addr;
  63                 unsigned int size;
  64         };
  65
  66         const struct isa_range *range;
  67         unsigned long pci_addr;
  68         unsigned int isa_addr;
  69         unsigned int size;
  70         int rlen = 0;
  71
  72         range = of_get_property(isa_node, "ranges", &rlen);
  73         if (range == NULL || (rlen < sizeof(struct isa_range)))
  74                 goto inval_range;
  75
  76         /* From "ISA Binding to 1275"
  77          * The ranges property is laid out as an array of elements,
  78          * each of which comprises:
  79          *   cells 0 - 1:       an ISA address
  80          *   cells 2 - 4:       a PCI address
  81          *                      (size depending on dev->n_addr_cells)
  82          *   cell 5:            the size of the range
  83          */
  84         if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO) {
  85                 range++;
  86                 rlen -= sizeof(struct isa_range);
  87                 if (rlen < sizeof(struct isa_range))
  88                         goto inval_range;
  89         }
  90         if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO)
  91                 goto inval_range;
  92
  93         isa_addr = range->isa_addr.a_lo;
  94         pci_addr = (unsigned long) range->pci_addr.a_mid << 32 |
  95                 range->pci_addr.a_lo;
  96
  97         /* Assume these are both zero. Note: We could fix that and
  98          * do a proper parsing instead ... oh well, that will do for
  99          * now as nobody uses fancy mappings for ISA bridges
 100          */
 101         if ((pci_addr != 0) || (isa_addr != 0)) {
 102                 printk(KERN_ERR "unexpected isa to pci mapping: %s\n",
 103                        __func__);
 104                 return;
 105         }
 106
 107         /* Align size and make sure it's cropped to 64K */
 108         size = PAGE_ALIGN(range->size);
 109         if (size > 0x10000)
 110                 size = 0x10000;
 111
 112         __ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE,
 113                      size, _PAGE_NO_CACHE|_PAGE_GUARDED);
 114         return;
 115
 116 inval_range:
 117         printk(KERN_ERR "no ISA IO ranges or unexpected isa range, "
 118                "mapping 64k\n");
 119         __ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE,
 120                      0x10000, _PAGE_NO_CACHE|_PAGE_GUARDED);
 121 }
 122
 123
 124 /**
 125  * isa_bridge_find_early - Find and map the ISA IO space early before
 126  *                         main PCI discovery. This is optionally called by
 127  *                         the arch code when adding PCI PHBs to get early
 128  *                         access to ISA IO ports
 129  */
 130 void __init isa_bridge_find_early(struct pci_controller *hose)
 131 {
 132         struct device_node *np, *parent = NULL, *tmp;
 133
 134         /* If we already have an ISA bridge, bail off */
 135         if (isa_bridge_devnode != NULL)
 136                 return;
 137
 138         /* For each "isa" node in the system. Note : we do a search by
 139          * type and not by name. It might be better to do by name but that's
 140          * what the code used to do and I don't want to break too much at
 141          * once. We can look into changing that separately
 142          */
 143         for_each_node_by_type(np, "isa") {
 144                 /* Look for our hose being a parent */
 145                 for (parent = of_get_parent(np); parent;) {
 146                         if (parent == hose->dn) {
 147                                 of_node_put(parent);
 148                                 break;
 149                         }
 150                         tmp = parent;
 151                         parent = of_get_parent(parent);
 152                         of_node_put(tmp);
 153                 }
 154                 if (parent != NULL)
 155                         break;
 156         }
 157         if (np == NULL)
 158                 return;
 159         isa_bridge_devnode = np;
 160
 161         /* Now parse the "ranges" property and setup the ISA mapping */
 162         pci_process_ISA_OF_ranges(np, hose->io_base_phys);
 163
 164         /* Set the global ISA io base to indicate we have an ISA bridge */
 165         isa_io_base = ISA_IO_BASE;
 166
 167         pr_debug("ISA bridge (early) is %s\n", np->full_name);
 168 }
 169
 170 /**
 171  * isa_bridge_find_late - Find and map the ISA IO space upon discovery of
 172  *                        a new ISA bridge
 173  */
 174 static void __devinit isa_bridge_find_late(struct pci_dev *pdev,
 175                                            struct device_node *devnode)
 176 {
 177         struct pci_controller *hose = pci_bus_to_host(pdev->bus);
 178
 179         /* Store ISA device node and PCI device */
 180         isa_bridge_devnode = of_node_get(devnode);
 181         isa_bridge_pcidev = pdev;
 182
 183         /* Now parse the "ranges" property and setup the ISA mapping */
 184         pci_process_ISA_OF_ranges(devnode, hose->io_base_phys);
 185
 186         /* Set the global ISA io base to indicate we have an ISA bridge */
 187         isa_io_base = ISA_IO_BASE;
 188
 189         pr_debug("ISA bridge (late) is %s on %s\n",
 190                  devnode->full_name, pci_name(pdev));
 191 }
 192
 193 /**
 194  * isa_bridge_remove - Remove/unmap an ISA bridge
 195  */
 196 static void isa_bridge_remove(void)
 197 {
 198         pr_debug("ISA bridge removed !\n");
 199
 200         /* Clear the global ISA io base to indicate that we have no more
 201          * ISA bridge. Note that drivers don't quite handle that, though
 202          * we should probably do something about it. But do we ever really
 203          * have ISA bridges being removed on machines using legacy devices ?
 204          */
 205         isa_io_base = ISA_IO_BASE;
 206
 207         /* Clear references to the bridge */
 208         of_node_put(isa_bridge_devnode);
 209         isa_bridge_devnode = NULL;
 210         isa_bridge_pcidev = NULL;
 211
 212         /* Unmap the ISA area */
 213         __iounmap_at((void *)ISA_IO_BASE, 0x10000);
 214 }
 215
 216 /**
 217  * isa_bridge_notify - Get notified of PCI devices addition/removal
 218  */
 219 static int __devinit isa_bridge_notify(struct notifier_block *nb,
 220                                        unsigned long action, void *data)
 221 {
 222         struct device *dev = data;
 223         struct pci_dev *pdev = to_pci_dev(dev);
 224         struct device_node *devnode = pci_device_to_OF_node(pdev);
 225
 226         switch(action) {
 227         case BUS_NOTIFY_ADD_DEVICE:
 228                 /* Check if we have an early ISA device, without PCI dev */
 229                 if (isa_bridge_devnode && isa_bridge_devnode == devnode &&
 230                     !isa_bridge_pcidev) {
 231                         pr_debug("ISA bridge PCI attached: %s\n",
 232                                  pci_name(pdev));
 233                         isa_bridge_pcidev = pdev;
 234                 }
 235
 236                 /* Check if we have no ISA device, and this happens to be one,
 237                  * register it as such if it has an OF device
 238                  */
 239                 if (!isa_bridge_devnode && devnode && devnode->type &&
 240                     !strcmp(devnode->type, "isa"))
 241                         isa_bridge_find_late(pdev, devnode);
 242
 243                 return 0;
 244         case BUS_NOTIFY_DEL_DEVICE:
 245                 /* Check if this our existing ISA device */
 246                 if (pdev == isa_bridge_pcidev ||
 247                     (devnode && devnode == isa_bridge_devnode))
 248                         isa_bridge_remove();
 249                 return 0;
 250         }
 251         return 0;
 252 }
 253
 254 static struct notifier_block isa_bridge_notifier = {
 255         .notifier_call = isa_bridge_notify
 256 };
 257
 258 /**
 259  * isa_bridge_init - register to be notified of ISA bridge addition/removal
 260  *
 261  */
 262 static int __init isa_bridge_init(void)
 263 {
 264         if (firmware_has_feature(FW_FEATURE_ISERIES))
 265                 return 0;
 266         bus_register_notifier(&pci_bus_type, &isa_bridge_notifier);
 267         return 0;
 268 }
 269 arch_initcall(isa_bridge_init);