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         void __iomem *(*map_bus)(struct pci_bus *, unsigned int, int);
  31 };
  32
  33 struct gen_pci_cfg_windows {
  34         struct resource                         res;
  35         struct resource                         *bus_range;
  36         void __iomem                            **win;
  37
  38         const 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         .map_bus        = gen_pci_map_cfg_bus_cam,
  69 };
  70
  71 static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus,
  72                                               unsigned int devfn,
  73                                               int where)
  74 {
  75         struct gen_pci *pci = bus->sysdata;
  76         resource_size_t idx = bus->number - pci->cfg.bus_range->start;
  77
  78         return pci->cfg.win[idx] + ((devfn << 12) | where);
  79 }
  80
  81 static struct gen_pci_cfg_bus_ops gen_pci_cfg_ecam_bus_ops = {
  82         .bus_shift      = 20,
  83         .map_bus        = gen_pci_map_cfg_bus_ecam,
  84 };
  85
  86 static struct pci_ops gen_pci_ops = {
  87         .read   = pci_generic_config_read,
  88         .write  = pci_generic_config_write,
  89 };
  90
  91 static const struct of_device_id gen_pci_of_match[] = {
  92         { .compatible = "pci-host-cam-generic",
  93           .data = &gen_pci_cfg_cam_bus_ops },
  94
  95         { .compatible = "pci-host-ecam-generic",
  96           .data = &gen_pci_cfg_ecam_bus_ops },
  97
  98         { },
  99 };
 100 MODULE_DEVICE_TABLE(of, gen_pci_of_match);
 101
 102 static void gen_pci_release_of_pci_ranges(struct gen_pci *pci)
 103 {
 104         pci_free_resource_list(&pci->resources);
 105 }
 106
 107 static int gen_pci_parse_request_of_pci_ranges(struct gen_pci *pci)
 108 {
 109         int err, res_valid = 0;
 110         struct device *dev = pci->host.dev.parent;
 111         struct device_node *np = dev->of_node;
 112         resource_size_t iobase;
 113         struct resource_entry *win;
 114
 115         err = of_pci_get_host_bridge_resources(np, 0, 0xff, &pci->resources,
 116                                                &iobase);
 117         if (err)
 118                 return err;
 119
 120         resource_list_for_each_entry(win, &pci->resources) {
 121                 struct resource *parent, *res = win->res;
 122
 123                 switch (resource_type(res)) {
 124                 case IORESOURCE_IO:
 125                         parent = &ioport_resource;
 126                         err = pci_remap_iospace(res, iobase);
 127                         if (err) {
 128                                 dev_warn(dev, "error %d: failed to map resource %pR\n",
 129                                          err, res);
 130                                 continue;
 131                         }
 132                         break;
 133                 case IORESOURCE_MEM:
 134                         parent = &iomem_resource;
 135                         res_valid |= !(res->flags & IORESOURCE_PREFETCH);
 136                         break;
 137                 case IORESOURCE_BUS:
 138                         pci->cfg.bus_range = res;
 139                 default:
 140                         continue;
 141                 }
 142
 143                 err = devm_request_resource(dev, parent, res);
 144                 if (err)
 145                         goto out_release_res;
 146         }
 147
 148         if (!res_valid) {
 149                 dev_err(dev, "non-prefetchable memory resource required\n");
 150                 err = -EINVAL;
 151                 goto out_release_res;
 152         }
 153
 154         return 0;
 155
 156 out_release_res:
 157         gen_pci_release_of_pci_ranges(pci);
 158         return err;
 159 }
 160
 161 static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
 162 {
 163         int err;
 164         u8 bus_max;
 165         resource_size_t busn;
 166         struct resource *bus_range;
 167         struct device *dev = pci->host.dev.parent;
 168         struct device_node *np = dev->of_node;
 169
 170         err = of_address_to_resource(np, 0, &pci->cfg.res);
 171         if (err) {
 172                 dev_err(dev, "missing \"reg\" property\n");
 173                 return err;
 174         }
 175
 176         /* Limit the bus-range to fit within reg */
 177         bus_max = pci->cfg.bus_range->start +
 178                   (resource_size(&pci->cfg.res) >> pci->cfg.ops->bus_shift) - 1;
 179         pci->cfg.bus_range->end = min_t(resource_size_t,
 180                                         pci->cfg.bus_range->end, bus_max);
 181
 182         pci->cfg.win = devm_kcalloc(dev, resource_size(pci->cfg.bus_range),
 183                                     sizeof(*pci->cfg.win), GFP_KERNEL);
 184         if (!pci->cfg.win)
 185                 return -ENOMEM;
 186
 187         /* Map our Configuration Space windows */
 188         if (!devm_request_mem_region(dev, pci->cfg.res.start,
 189                                      resource_size(&pci->cfg.res),
 190                                      "Configuration Space"))
 191                 return -ENOMEM;
 192
 193         bus_range = pci->cfg.bus_range;
 194         for (busn = bus_range->start; busn <= bus_range->end; ++busn) {
 195                 u32 idx = busn - bus_range->start;
 196                 u32 sz = 1 << pci->cfg.ops->bus_shift;
 197
 198                 pci->cfg.win[idx] = devm_ioremap(dev,
 199                                                  pci->cfg.res.start + busn * sz,
 200                                                  sz);
 201                 if (!pci->cfg.win[idx])
 202                         return -ENOMEM;
 203         }
 204
 205         return 0;
 206 }
 207
 208 static int gen_pci_probe(struct platform_device *pdev)
 209 {
 210         int err;
 211         const char *type;
 212         const struct of_device_id *of_id;
 213         const int *prop;
 214         struct device *dev = &pdev->dev;
 215         struct device_node *np = dev->of_node;
 216         struct gen_pci *pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
 217         struct pci_bus *bus, *child;
 218
 219         if (!pci)
 220                 return -ENOMEM;
 221
 222         type = of_get_property(np, "device_type", NULL);
 223         if (!type || strcmp(type, "pci")) {
 224                 dev_err(dev, "invalid \"device_type\" %s\n", type);
 225                 return -EINVAL;
 226         }
 227
 228         prop = of_get_property(of_chosen, "linux,pci-probe-only", NULL);
 229         if (prop) {
 230                 if (*prop)
 231                         pci_add_flags(PCI_PROBE_ONLY);
 232                 else
 233                         pci_clear_flags(PCI_PROBE_ONLY);
 234         }
 235
 236         of_id = of_match_node(gen_pci_of_match, np);
 237         pci->cfg.ops = of_id->data;
 238         gen_pci_ops.map_bus = pci->cfg.ops->map_bus;
 239         pci->host.dev.parent = dev;
 240         INIT_LIST_HEAD(&pci->host.windows);
 241         INIT_LIST_HEAD(&pci->resources);
 242
 243         /* Parse our PCI ranges and request their resources */
 244         err = gen_pci_parse_request_of_pci_ranges(pci);
 245         if (err)
 246                 return err;
 247
 248         /* Parse and map our Configuration Space windows */
 249         err = gen_pci_parse_map_cfg_windows(pci);
 250         if (err) {
 251                 gen_pci_release_of_pci_ranges(pci);
 252                 return err;
 253         }
 254
 255         /* Do not reassign resources if probe only */
 256         if (!pci_has_flag(PCI_PROBE_ONLY))
 257                 pci_add_flags(PCI_REASSIGN_ALL_RSRC | PCI_REASSIGN_ALL_BUS);
 258
 259         bus = pci_scan_root_bus(dev, 0, &gen_pci_ops, pci, &pci->resources);
 260         if (!bus) {
 261                 dev_err(dev, "Scanning rootbus failed");
 262                 return -ENODEV;
 263         }
 264
 265         pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
 266
 267         if (!pci_has_flag(PCI_PROBE_ONLY)) {
 268                 pci_bus_size_bridges(bus);
 269                 pci_bus_assign_resources(bus);
 270
 271                 list_for_each_entry(child, &bus->children, node)
 272                         pcie_bus_configure_settings(child);
 273         }
 274
 275         pci_bus_add_devices(bus);
 276         return 0;
 277 }
 278
 279 static struct platform_driver gen_pci_driver = {
 280         .driver = {
 281                 .name = "pci-host-generic",
 282                 .of_match_table = gen_pci_of_match,
 283         },
 284         .probe = gen_pci_probe,
 285 };
 286 module_platform_driver(gen_pci_driver);
 287
 288 MODULE_DESCRIPTION("Generic PCI host driver");
 289 MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
 290 MODULE_LICENSE("GPL v2");