drivers/pci/host/pci-host-generic.c

   1 /*
   2  * Simple, generic PCI host controller driver targetting firmware-initialised
   3  * systems and virtual machines (e.g. the PCI emulation provided by kvmtool).
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  *
  17  * Copyright (C) 2014 ARM Limited
  18  *
  19  * Author: Will Deacon <will.deacon@arm.com>
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/of_address.h>
  25 #include <linux/of_pci.h>
  26 #include <linux/platform_device.h>
  27
  28 struct gen_pci_cfg_bus_ops {
  29         u32 bus_shift;
  30         struct pci_ops ops;
  31 };
  32
  33 struct gen_pci_cfg_windows {
  34         struct resource                         res;
  35         struct resource                         *bus_range;
  36         void __iomem                            **win;
  37
  38         struct gen_pci_cfg_bus_ops              *ops;
  39 };
  40
  41 /*
  42  * ARM pcibios functions expect the ARM struct pci_sys_data as the PCI
  43  * sysdata.  Add pci_sys_data as the first element in struct gen_pci so
  44  * that when we use a gen_pci pointer as sysdata, it is also a pointer to
  45  * a struct pci_sys_data.
  46  */
  47 struct gen_pci {
  48 #ifdef CONFIG_ARM
  49         struct pci_sys_data                     sys;
  50 #endif
  51         struct pci_host_bridge                  host;
  52         struct gen_pci_cfg_windows              cfg;
  53         struct list_head                        resources;
  54 };
  55
  56 static void __iomem *gen_pci_map_cfg_bus_cam(struct pci_bus *bus,
  57                                              unsigned int devfn,
  58                                              int where)
  59 {
  60         struct gen_pci *pci = bus->sysdata;
  61         resource_size_t idx = bus->number - pci->cfg.bus_range->start;
  62
  63         return pci->cfg.win[idx] + ((devfn << 8) | where);
  64 }
  65
  66 static struct gen_pci_cfg_bus_ops gen_pci_cfg_cam_bus_ops = {
  67         .bus_shift      = 16,
  68         .ops            = {
  69                 .map_bus        = gen_pci_map_cfg_bus_cam,
  70                 .read           = pci_generic_config_read,
  71                 .write          = pci_generic_config_write,
  72         }
  73 };
  74
  75 static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus,
  76                                               unsigned int devfn,
  77                                               int where)
  78 {
  79         struct gen_pci *pci = bus->sysdata;
  80         resource_size_t idx = bus->number - pci->cfg.bus_range->start;
  81
  82         return pci->cfg.win[idx] + ((devfn << 12) | where);
  83 }
  84
  85 static struct gen_pci_cfg_bus_ops gen_pci_cfg_ecam_bus_ops = {
  86         .bus_shift      = 20,
  87         .ops            = {
  88                 .map_bus        = gen_pci_map_cfg_bus_ecam,
  89                 .read           = pci_generic_config_read,
  90                 .write          = pci_generic_config_write,
  91         }
  92 };
  93
  94 static const struct of_device_id gen_pci_of_match[] = {
  95         { .compatible = "pci-host-cam-generic",
  96           .data = &gen_pci_cfg_cam_bus_ops },
  97
  98         { .compatible = "pci-host-ecam-generic",
  99           .data = &gen_pci_cfg_ecam_bus_ops },
 100
 101         { },
 102 };
 103 MODULE_DEVICE_TABLE(of, gen_pci_of_match);
 104
 105 static void gen_pci_release_of_pci_ranges(struct gen_pci *pci)
 106 {
 107         pci_free_resource_list(&pci->resources);
 108 }
 109
 110 static int gen_pci_parse_request_of_pci_ranges(struct gen_pci *pci)
 111 {
 112         int err, res_valid = 0;
 113         struct device *dev = pci->host.dev.parent;
 114         struct device_node *np = dev->of_node;
 115         resource_size_t iobase;
 116         struct resource_entry *win;
 117
 118         err = of_pci_get_host_bridge_resources(np, 0, 0xff, &pci->resources,
 119                                                &iobase);
 120         if (err)
 121                 return err;
 122
 123         resource_list_for_each_entry(win, &pci->resources) {
 124                 struct resource *parent, *res = win->res;
 125
 126                 switch (resource_type(res)) {
 127                 case IORESOURCE_IO:
 128                         parent = &ioport_resource;
 129                         err = pci_remap_iospace(res, iobase);
 130                         if (err) {
 131                                 dev_warn(dev, "error %d: failed to map resource %pR\n",
 132                                          err, res);
 133                                 continue;
 134                         }
 135                         break;
 136                 case IORESOURCE_MEM:
 137                         parent = &iomem_resource;
 138                         res_valid |= !(res->flags & IORESOURCE_PREFETCH);
 139                         break;
 140                 case IORESOURCE_BUS:
 141                         pci->cfg.bus_range = res;
 142                 default:
 143                         continue;
 144                 }
 145
 146                 err = devm_request_resource(dev, parent, res);
 147                 if (err)
 148                         goto out_release_res;
 149         }
 150
 151         if (!res_valid) {
 152                 dev_err(dev, "non-prefetchable memory resource required\n");
 153                 err = -EINVAL;
 154                 goto out_release_res;
 155         }
 156
 157         return 0;
 158
 159 out_release_res:
 160         gen_pci_release_of_pci_ranges(pci);
 161         return err;
 162 }
 163
 164 static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
 165 {
 166         int err;
 167         u8 bus_max;
 168         resource_size_t busn;
 169         struct resource *bus_range;
 170         struct device *dev = pci->host.dev.parent;
 171         struct device_node *np = dev->of_node;
 172         u32 sz = 1 << pci->cfg.ops->bus_shift;
 173
 174         err = of_address_to_resource(np, 0, &pci->cfg.res);
 175         if (err) {
 176                 dev_err(dev, "missing \"reg\" property\n");
 177                 return err;
 178         }
 179
 180         /* Limit the bus-range to fit within reg */
 181         bus_max = pci->cfg.bus_range->start +
 182                   (resource_size(&pci->cfg.res) >> pci->cfg.ops->bus_shift) - 1;
 183         pci->cfg.bus_range->end = min_t(resource_size_t,
 184                                         pci->cfg.bus_range->end, bus_max);
 185
 186         pci->cfg.win = devm_kcalloc(dev, resource_size(pci->cfg.bus_range),
 187                                     sizeof(*pci->cfg.win), GFP_KERNEL);
 188         if (!pci->cfg.win)
 189                 return -ENOMEM;
 190
 191         /* Map our Configuration Space windows */
 192         if (!devm_request_mem_region(dev, pci->cfg.res.start,
 193                                      resource_size(&pci->cfg.res),
 194                                      "Configuration Space"))
 195                 return -ENOMEM;
 196
 197         bus_range = pci->cfg.bus_range;
 198         for (busn = bus_range->start; busn <= bus_range->end; ++busn) {
 199                 u32 idx = busn - bus_range->start;
 200
 201                 pci->cfg.win[idx] = devm_ioremap(dev,
 202                                                  pci->cfg.res.start + idx * sz,
 203                                                  sz);
 204                 if (!pci->cfg.win[idx])
 205                         return -ENOMEM;
 206         }
 207
 208         return 0;
 209 }
 210
 211 static int gen_pci_probe(struct platform_device *pdev)
 212 {
 213         int err;
 214         const char *type;
 215         const struct of_device_id *of_id;
 216         struct device *dev = &pdev->dev;
 217         struct device_node *np = dev->of_node;
 218         struct gen_pci *pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
 219         struct pci_bus *bus, *child;
 220
 221         if (!pci)
 222                 return -ENOMEM;
 223
 224         type = of_get_property(np, "device_type", NULL);
 225         if (!type || strcmp(type, "pci")) {
 226                 dev_err(dev, "invalid \"device_type\" %s\n", type);
 227                 return -EINVAL;
 228         }
 229
 230         of_pci_check_probe_only();
 231
 232         of_id = of_match_node(gen_pci_of_match, np);
 233         pci->cfg.ops = (struct gen_pci_cfg_bus_ops *)of_id->data;
 234         pci->host.dev.parent = dev;
 235         INIT_LIST_HEAD(&pci->host.windows);
 236         INIT_LIST_HEAD(&pci->resources);
 237
 238         /* Parse our PCI ranges and request their resources */
 239         err = gen_pci_parse_request_of_pci_ranges(pci);
 240         if (err)
 241                 return err;
 242
 243         /* Parse and map our Configuration Space windows */
 244         err = gen_pci_parse_map_cfg_windows(pci);
 245         if (err) {
 246                 gen_pci_release_of_pci_ranges(pci);
 247                 return err;
 248         }
 249
 250         /* Do not reassign resources if probe only */
 251         if (!pci_has_flag(PCI_PROBE_ONLY))
 252                 pci_add_flags(PCI_REASSIGN_ALL_RSRC | PCI_REASSIGN_ALL_BUS);
 253
 254
 255         bus = pci_scan_root_bus(dev, pci->cfg.bus_range->start,
 256                                 &pci->cfg.ops->ops, pci, &pci->resources);
 257         if (!bus) {
 258                 dev_err(dev, "Scanning rootbus failed");
 259                 return -ENODEV;
 260         }
 261
 262         pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
 263
 264         if (!pci_has_flag(PCI_PROBE_ONLY)) {
 265                 pci_bus_size_bridges(bus);
 266                 pci_bus_assign_resources(bus);
 267
 268                 list_for_each_entry(child, &bus->children, node)
 269                         pcie_bus_configure_settings(child);
 270         }
 271
 272         pci_bus_add_devices(bus);
 273         return 0;
 274 }
 275
 276 static struct platform_driver gen_pci_driver = {
 277         .driver = {
 278                 .name = "pci-host-generic",
 279                 .of_match_table = gen_pci_of_match,
 280         },
 281         .probe = gen_pci_probe,
 282 };
 283 module_platform_driver(gen_pci_driver);
 284
 285 MODULE_DESCRIPTION("Generic PCI host driver");
 286 MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
 287 MODULE_LICENSE("GPL v2");