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
  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);