arch/powerpc/kernel/isa-bridge.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Routines for tracking a legacy ISA bridge
   4  *
   5  * Copyrigh 2007 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
   6  *
   7  * Some bits and pieces moved over from pci_64.c
   8  *
   9  * Copyrigh 2003 Anton Blanchard <anton@au.ibm.com>, IBM Corp.
  10  */
  11
  12 #define DEBUG
  13
  14 #include <linux/kernel.h>
  15 #include <linux/pci.h>
  16 #include <linux/string.h>
  17 #include <linux/export.h>
  18 #include <linux/init.h>
  19 #include <linux/mm.h>
  20 #include <linux/notifier.h>
  21 #include <linux/of_address.h>
  22 #include <linux/vmalloc.h>
  23
  24 #include <asm/processor.h>
  25 #include <asm/io.h>
  26 #include <asm/pci-bridge.h>
  27 #include <asm/machdep.h>
  28 #include <asm/ppc-pci.h>
  29 #include <asm/isa-bridge.h>
  30
  31 unsigned long isa_io_base;      /* NULL if no ISA bus */
  32 EXPORT_SYMBOL(isa_io_base);
  33
  34 /* Cached ISA bridge dev. */
  35 static struct device_node *isa_bridge_devnode;
  36 struct pci_dev *isa_bridge_pcidev;
  37 EXPORT_SYMBOL_GPL(isa_bridge_pcidev);
  38
  39 #define ISA_SPACE_MASK 0x1
  40 #define ISA_SPACE_IO 0x1
  41
  42 static void remap_isa_base(phys_addr_t pa, unsigned long size)
  43 {
  44         WARN_ON_ONCE(ISA_IO_BASE & ~PAGE_MASK);
  45         WARN_ON_ONCE(pa & ~PAGE_MASK);
  46         WARN_ON_ONCE(size & ~PAGE_MASK);
  47
  48         if (slab_is_available()) {
  49                 if (vmap_page_range(ISA_IO_BASE, ISA_IO_BASE + size, pa,
  50                                     pgprot_noncached(PAGE_KERNEL)))
  51                         vunmap_range(ISA_IO_BASE, ISA_IO_BASE + size);
  52         } else {
  53                 early_ioremap_range(ISA_IO_BASE, pa, size,
  54                                 pgprot_noncached(PAGE_KERNEL));
  55         }
  56 }
  57
  58 static int process_ISA_OF_ranges(struct device_node *isa_node,
  59                                  unsigned long phb_io_base_phys)
  60 {
  61         unsigned int size;
  62         struct of_range_parser parser;
  63         struct of_range range;
  64
  65         if (of_range_parser_init(&parser, isa_node))
  66                 goto inval_range;
  67
  68         for_each_of_range(&parser, &range) {
  69                 if ((range.flags & ISA_SPACE_MASK) != ISA_SPACE_IO)
  70                         continue;
  71
  72                 if (range.cpu_addr == OF_BAD_ADDR) {
  73                         pr_err("ISA: Bad CPU mapping: %s\n", __func__);
  74                         return -EINVAL;
  75                 }
  76
  77                 /* We need page alignment */
  78                 if ((range.bus_addr & ~PAGE_MASK) || (range.cpu_addr & ~PAGE_MASK)) {
  79                         pr_warn("ISA: bridge %pOF has non aligned IO range\n", isa_node);
  80                         return -EINVAL;
  81                 }
  82
  83                 /* Align size and make sure it's cropped to 64K */
  84                 size = PAGE_ALIGN(range.size);
  85                 if (size > 0x10000)
  86                         size = 0x10000;
  87
  88                 if (!phb_io_base_phys)
  89                         phb_io_base_phys = range.cpu_addr;
  90
  91                 remap_isa_base(phb_io_base_phys, size);
  92                 return 0;
  93         }
  94
  95 inval_range:
  96         if (phb_io_base_phys) {
  97                 pr_err("no ISA IO ranges or unexpected isa range, mapping 64k\n");
  98                 remap_isa_base(phb_io_base_phys, 0x10000);
  99                 return 0;
 100         }
 101         return -EINVAL;
 102 }
 103
 104
 105 /**
 106  * isa_bridge_find_early - Find and map the ISA IO space early before
 107  *                         main PCI discovery. This is optionally called by
 108  *                         the arch code when adding PCI PHBs to get early
 109  *                         access to ISA IO ports
 110  */
 111 void __init isa_bridge_find_early(struct pci_controller *hose)
 112 {
 113         struct device_node *np, *parent = NULL, *tmp;
 114
 115         /* If we already have an ISA bridge, bail off */
 116         if (isa_bridge_devnode != NULL)
 117                 return;
 118
 119         /* For each "isa" node in the system. Note : we do a search by
 120          * type and not by name. It might be better to do by name but that's
 121          * what the code used to do and I don't want to break too much at
 122          * once. We can look into changing that separately
 123          */
 124         for_each_node_by_type(np, "isa") {
 125                 /* Look for our hose being a parent */
 126                 for (parent = of_get_parent(np); parent;) {
 127                         if (parent == hose->dn) {
 128                                 of_node_put(parent);
 129                                 break;
 130                         }
 131                         tmp = parent;
 132                         parent = of_get_parent(parent);
 133                         of_node_put(tmp);
 134                 }
 135                 if (parent != NULL)
 136                         break;
 137         }
 138         if (np == NULL)
 139                 return;
 140         isa_bridge_devnode = np;
 141
 142         /* Now parse the "ranges" property and setup the ISA mapping */
 143         process_ISA_OF_ranges(np, hose->io_base_phys);
 144
 145         /* Set the global ISA io base to indicate we have an ISA bridge */
 146         isa_io_base = ISA_IO_BASE;
 147
 148         pr_debug("ISA bridge (early) is %pOF\n", np);
 149 }
 150
 151 /**
 152  * isa_bridge_find_early - Find and map the ISA IO space early before
 153  *                         main PCI discovery. This is optionally called by
 154  *                         the arch code when adding PCI PHBs to get early
 155  *                         access to ISA IO ports
 156  */
 157 void __init isa_bridge_init_non_pci(struct device_node *np)
 158 {
 159         int ret;
 160
 161         /* If we already have an ISA bridge, bail off */
 162         if (isa_bridge_devnode != NULL)
 163                 return;
 164
 165         ret = process_ISA_OF_ranges(np, 0);
 166         if (ret)
 167                 return;
 168
 169         /* Got it */
 170         isa_bridge_devnode = np;
 171
 172         /* Set the global ISA io base to indicate we have an ISA bridge
 173          * and map it
 174          */
 175         isa_io_base = ISA_IO_BASE;
 176
 177         pr_debug("ISA: Non-PCI bridge is %pOF\n", np);
 178 }
 179
 180 /**
 181  * isa_bridge_find_late - Find and map the ISA IO space upon discovery of
 182  *                        a new ISA bridge
 183  */
 184 static void isa_bridge_find_late(struct pci_dev *pdev,
 185                                  struct device_node *devnode)
 186 {
 187         struct pci_controller *hose = pci_bus_to_host(pdev->bus);
 188
 189         /* Store ISA device node and PCI device */
 190         isa_bridge_devnode = of_node_get(devnode);
 191         isa_bridge_pcidev = pdev;
 192
 193         /* Now parse the "ranges" property and setup the ISA mapping */
 194         process_ISA_OF_ranges(devnode, hose->io_base_phys);
 195
 196         /* Set the global ISA io base to indicate we have an ISA bridge */
 197         isa_io_base = ISA_IO_BASE;
 198
 199         pr_debug("ISA bridge (late) is %pOF on %s\n",
 200                  devnode, pci_name(pdev));
 201 }
 202
 203 /**
 204  * isa_bridge_remove - Remove/unmap an ISA bridge
 205  */
 206 static void isa_bridge_remove(void)
 207 {
 208         pr_debug("ISA bridge removed !\n");
 209
 210         /* Clear the global ISA io base to indicate that we have no more
 211          * ISA bridge. Note that drivers don't quite handle that, though
 212          * we should probably do something about it. But do we ever really
 213          * have ISA bridges being removed on machines using legacy devices ?
 214          */
 215         isa_io_base = ISA_IO_BASE;
 216
 217         /* Clear references to the bridge */
 218         of_node_put(isa_bridge_devnode);
 219         isa_bridge_devnode = NULL;
 220         isa_bridge_pcidev = NULL;
 221
 222         /* Unmap the ISA area */
 223         vunmap_range(ISA_IO_BASE, ISA_IO_BASE + 0x10000);
 224 }
 225
 226 /**
 227  * isa_bridge_notify - Get notified of PCI devices addition/removal
 228  */
 229 static int isa_bridge_notify(struct notifier_block *nb, unsigned long action,
 230                              void *data)
 231 {
 232         struct device *dev = data;
 233         struct pci_dev *pdev = to_pci_dev(dev);
 234         struct device_node *devnode = pci_device_to_OF_node(pdev);
 235
 236         switch(action) {
 237         case BUS_NOTIFY_ADD_DEVICE:
 238                 /* Check if we have an early ISA device, without PCI dev */
 239                 if (isa_bridge_devnode && isa_bridge_devnode == devnode &&
 240                     !isa_bridge_pcidev) {
 241                         pr_debug("ISA bridge PCI attached: %s\n",
 242                                  pci_name(pdev));
 243                         isa_bridge_pcidev = pdev;
 244                 }
 245
 246                 /* Check if we have no ISA device, and this happens to be one,
 247                  * register it as such if it has an OF device
 248                  */
 249                 if (!isa_bridge_devnode && of_node_is_type(devnode, "isa"))
 250                         isa_bridge_find_late(pdev, devnode);
 251
 252                 return 0;
 253         case BUS_NOTIFY_DEL_DEVICE:
 254                 /* Check if this our existing ISA device */
 255                 if (pdev == isa_bridge_pcidev ||
 256                     (devnode && devnode == isa_bridge_devnode))
 257                         isa_bridge_remove();
 258                 return 0;
 259         }
 260         return 0;
 261 }
 262
 263 static struct notifier_block isa_bridge_notifier = {
 264         .notifier_call = isa_bridge_notify
 265 };
 266
 267 /**
 268  * isa_bridge_init - register to be notified of ISA bridge addition/removal
 269  *
 270  */
 271 static int __init isa_bridge_init(void)
 272 {
 273         bus_register_notifier(&pci_bus_type, &isa_bridge_notifier);
 274         return 0;
 275 }
 276 arch_initcall(isa_bridge_init);