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/pci-ecam.h>
  23 #include <linux/slab.h>
  24
  25 /*
  26  * On 64-bit systems, we do a single ioremap for the whole config space
  27  * since we have enough virtual address range available.  On 32-bit, we
  28  * ioremap the config space for each bus individually.
  29  */
  30 static const bool per_bus_mapping = !IS_ENABLED(CONFIG_64BIT);
  31
  32 /*
  33  * Create a PCI config space window
  34  *  - reserve mem region
  35  *  - alloc struct pci_config_window with space for all mappings
  36  *  - ioremap the config space
  37  */
  38 struct pci_config_window *pci_ecam_create(struct device *dev,
  39                 struct resource *cfgres, struct resource *busr,
  40                 struct pci_ecam_ops *ops)
  41 {
  42         struct pci_config_window *cfg;
  43         unsigned int bus_range, bus_range_max, bsz;
  44         struct resource *conflict;
  45         int i, err;
  46
  47         if (busr->start > busr->end)
  48                 return ERR_PTR(-EINVAL);
  49
  50         cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
  51         if (!cfg)
  52                 return ERR_PTR(-ENOMEM);
  53
  54         cfg->parent = dev;
  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] =
  88                                 pci_remap_cfgspace(cfgres->start + i * bsz,
  89                                                    bsz);
  90                         if (!cfg->winp[i])
  91                                 goto err_exit_iomap;
  92                 }
  93         } else {
  94                 cfg->win = pci_remap_cfgspace(cfgres->start, bus_range * bsz);
  95                 if (!cfg->win)
  96                         goto err_exit_iomap;
  97         }
  98
  99         if (ops->init) {
 100                 err = ops->init(cfg);
 101                 if (err)
 102                         goto err_exit;
 103         }
 104         dev_info(dev, "ECAM at %pR for %pR\n", &cfg->res, &cfg->busr);
 105         return cfg;
 106
 107 err_exit_iomap:
 108         dev_err(dev, "ECAM ioremap failed\n");
 109 err_exit_malloc:
 110         err = -ENOMEM;
 111 err_exit:
 112         pci_ecam_free(cfg);
 113         return ERR_PTR(err);
 114 }
 115
 116 void pci_ecam_free(struct pci_config_window *cfg)
 117 {
 118         int i;
 119
 120         if (per_bus_mapping) {
 121                 if (cfg->winp) {
 122                         for (i = 0; i < resource_size(&cfg->busr); i++)
 123                                 if (cfg->winp[i])
 124                                         iounmap(cfg->winp[i]);
 125                         kfree(cfg->winp);
 126                 }
 127         } else {
 128                 if (cfg->win)
 129                         iounmap(cfg->win);
 130         }
 131         if (cfg->res.parent)
 132                 release_resource(&cfg->res);
 133         kfree(cfg);
 134 }
 135
 136 /*
 137  * Function to implement the pci_ops ->map_bus method
 138  */
 139 void __iomem *pci_ecam_map_bus(struct pci_bus *bus, unsigned int devfn,
 140                                int where)
 141 {
 142         struct pci_config_window *cfg = bus->sysdata;
 143         unsigned int devfn_shift = cfg->ops->bus_shift - 8;
 144         unsigned int busn = bus->number;
 145         void __iomem *base;
 146
 147         if (busn < cfg->busr.start || busn > cfg->busr.end)
 148                 return NULL;
 149
 150         busn -= cfg->busr.start;
 151         if (per_bus_mapping)
 152                 base = cfg->winp[busn];
 153         else
 154                 base = cfg->win + (busn << cfg->ops->bus_shift);
 155         return base + (devfn << devfn_shift) + where;
 156 }
 157
 158 /* ECAM ops */
 159 struct pci_ecam_ops pci_generic_ecam_ops = {
 160         .bus_shift      = 20,
 161         .pci_ops        = {
 162                 .map_bus        = pci_ecam_map_bus,
 163                 .read           = pci_generic_config_read,
 164                 .write          = pci_generic_config_write,
 165         }
 166 };
 167
 168 #if defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS)
 169 /* ECAM ops for 32-bit access only (non-compliant) */
 170 struct pci_ecam_ops pci_32b_ops = {
 171         .bus_shift      = 20,
 172         .pci_ops        = {
 173                 .map_bus        = pci_ecam_map_bus,
 174                 .read           = pci_generic_config_read32,
 175                 .write          = pci_generic_config_write32,
 176         }
 177 };
 178 #endif