drivers/pci/ecam.c

   1 /*
   2  * Copyright 2016 Broadcom
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2, as
   6  * published by the Free Software Foundation (the "GPL").
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License version 2 (GPLv2) for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * version 2 (GPLv2) along with this source code.
  15  */
  16
  17 #include <linux/device.h>
  18 #include <linux/io.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/pci.h>
  22 #include <linux/slab.h>
  23
  24 #include "ecam.h"
  25
  26 /*
  27  * On 64-bit systems, we do a single ioremap for the whole config space
  28  * since we have enough virtual address range available.  On 32-bit, we
  29  * ioremap the config space for each bus individually.
  30  */
  31 static const bool per_bus_mapping = !config_enabled(CONFIG_64BIT);
  32
  33 /*
  34  * Create a PCI config space window
  35  *  - reserve mem region
  36  *  - alloc struct pci_config_window with space for all mappings
  37  *  - ioremap the config space
  38  */
  39 struct pci_config_window *pci_ecam_create(struct device *dev,
  40                 struct resource *cfgres, struct resource *busr,
  41                 struct pci_ecam_ops *ops)
  42 {
  43         struct pci_config_window *cfg;
  44         unsigned int bus_range, bus_range_max, bsz;
  45         struct resource *conflict;
  46         int i, err;
  47
  48         if (busr->start > busr->end)
  49                 return ERR_PTR(-EINVAL);
  50
  51         cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
  52         if (!cfg)
  53                 return ERR_PTR(-ENOMEM);
  54
  55         cfg->ops = ops;
  56         cfg->busr.start = busr->start;
  57         cfg->busr.end = busr->end;
  58         cfg->busr.flags = IORESOURCE_BUS;
  59         bus_range = resource_size(&cfg->busr);
  60         bus_range_max = resource_size(cfgres) >> ops->bus_shift;
  61         if (bus_range > bus_range_max) {
  62                 bus_range = bus_range_max;
  63                 cfg->busr.end = busr->start + bus_range - 1;
  64                 dev_warn(dev, "ECAM area %pR can only accommodate %pR (reduced from %pR desired)\n",
  65                          cfgres, &cfg->busr, busr);
  66         }
  67         bsz = 1 << ops->bus_shift;
  68
  69         cfg->res.start = cfgres->start;
  70         cfg->res.end = cfgres->end;
  71         cfg->res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  72         cfg->res.name = "PCI ECAM";
  73
  74         conflict = request_resource_conflict(&iomem_resource, &cfg->res);
  75         if (conflict) {
  76                 err = -EBUSY;
  77                 dev_err(dev, "can't claim ECAM area %pR: address conflict with %s %pR\n",
  78                         &cfg->res, conflict->name, conflict);
  79                 goto err_exit;
  80         }
  81
  82         if (per_bus_mapping) {
  83                 cfg->winp = kcalloc(bus_range, sizeof(*cfg->winp), GFP_KERNEL);
  84                 if (!cfg->winp)
  85                         goto err_exit_malloc;
  86                 for (i = 0; i < bus_range; i++) {
  87                         cfg->winp[i] = ioremap(cfgres->start + i * bsz, bsz);
  88                         if (!cfg->winp[i])
  89                                 goto err_exit_iomap;
  90                 }
  91         } else {
  92                 cfg->win = ioremap(cfgres->start, bus_range * bsz);
  93                 if (!cfg->win)
  94                         goto err_exit_iomap;
  95         }
  96
  97         if (ops->init) {
  98                 err = ops->init(dev, cfg);
  99                 if (err)
 100                         goto err_exit;
 101         }
 102         dev_info(dev, "ECAM at %pR for %pR\n", &cfg->res, &cfg->busr);
 103         return cfg;
 104
 105 err_exit_iomap:
 106         dev_err(dev, "ECAM ioremap failed\n");
 107 err_exit_malloc:
 108         err = -ENOMEM;
 109 err_exit:
 110         pci_ecam_free(cfg);
 111         return ERR_PTR(err);
 112 }
 113
 114 void pci_ecam_free(struct pci_config_window *cfg)
 115 {
 116         int i;
 117
 118         if (per_bus_mapping) {
 119                 if (cfg->winp) {
 120                         for (i = 0; i < resource_size(&cfg->busr); i++)
 121                                 if (cfg->winp[i])
 122                                         iounmap(cfg->winp[i]);
 123                         kfree(cfg->winp);
 124                 }
 125         } else {
 126                 if (cfg->win)
 127                         iounmap(cfg->win);
 128         }
 129         if (cfg->res.parent)
 130                 release_resource(&cfg->res);
 131         kfree(cfg);
 132 }
 133
 134 /*
 135  * Function to implement the pci_ops ->map_bus method
 136  */
 137 void __iomem *pci_ecam_map_bus(struct pci_bus *bus, unsigned int devfn,
 138                                int where)
 139 {
 140         struct pci_config_window *cfg = bus->sysdata;
 141         unsigned int devfn_shift = cfg->ops->bus_shift - 8;
 142         unsigned int busn = bus->number;
 143         void __iomem *base;
 144
 145         if (busn < cfg->busr.start || busn > cfg->busr.end)
 146                 return NULL;
 147
 148         busn -= cfg->busr.start;
 149         if (per_bus_mapping)
 150                 base = cfg->winp[busn];
 151         else
 152                 base = cfg->win + (busn << cfg->ops->bus_shift);
 153         return base + (devfn << devfn_shift) + where;
 154 }
 155
 156 /* ECAM ops */
 157 struct pci_ecam_ops pci_generic_ecam_ops = {
 158         .bus_shift      = 20,
 159         .pci_ops        = {
 160                 .map_bus        = pci_ecam_map_bus,
 161                 .read           = pci_generic_config_read,
 162                 .write          = pci_generic_config_write,
 163         }
 164 };