drivers/xen/xen-pciback/conf_space_quirks.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * PCI Backend - Handle special overlays for broken devices.
   4  *
   5  * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
   6  * Author: Chris Bookholt <hap10@epoch.ncsc.mil>
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/pci.h>
  11 #include "pciback.h"
  12 #include "conf_space.h"
  13 #include "conf_space_quirks.h"
  14
  15 LIST_HEAD(xen_pcibk_quirks);
  16 static inline const struct pci_device_id *
  17 match_one_device(const struct pci_device_id *id, const struct pci_dev *dev)
  18 {
  19         if ((id->vendor == PCI_ANY_ID || id->vendor == dev->vendor) &&
  20             (id->device == PCI_ANY_ID || id->device == dev->device) &&
  21             (id->subvendor == PCI_ANY_ID ||
  22                                 id->subvendor == dev->subsystem_vendor) &&
  23             (id->subdevice == PCI_ANY_ID ||
  24                                 id->subdevice == dev->subsystem_device) &&
  25             !((id->class ^ dev->class) & id->class_mask))
  26                 return id;
  27         return NULL;
  28 }
  29
  30 static struct xen_pcibk_config_quirk *xen_pcibk_find_quirk(struct pci_dev *dev)
  31 {
  32         struct xen_pcibk_config_quirk *tmp_quirk;
  33
  34         list_for_each_entry(tmp_quirk, &xen_pcibk_quirks, quirks_list)
  35                 if (match_one_device(&tmp_quirk->devid, dev) != NULL)
  36                         goto out;
  37         tmp_quirk = NULL;
  38         printk(KERN_DEBUG DRV_NAME
  39                ": quirk didn't match any device known\n");
  40 out:
  41         return tmp_quirk;
  42 }
  43
  44 static inline void register_quirk(struct xen_pcibk_config_quirk *quirk)
  45 {
  46         list_add_tail(&quirk->quirks_list, &xen_pcibk_quirks);
  47 }
  48
  49 int xen_pcibk_field_is_dup(struct pci_dev *dev, unsigned int reg)
  50 {
  51         int ret = 0;
  52         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
  53         struct config_field_entry *cfg_entry;
  54
  55         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
  56                 if (OFFSET(cfg_entry) == reg) {
  57                         ret = 1;
  58                         break;
  59                 }
  60         }
  61         return ret;
  62 }
  63
  64 int xen_pcibk_config_quirks_add_field(struct pci_dev *dev, struct config_field
  65                                     *field)
  66 {
  67         int err = 0;
  68
  69         switch (field->size) {
  70         case 1:
  71                 field->u.b.read = xen_pcibk_read_config_byte;
  72                 field->u.b.write = xen_pcibk_write_config_byte;
  73                 break;
  74         case 2:
  75                 field->u.w.read = xen_pcibk_read_config_word;
  76                 field->u.w.write = xen_pcibk_write_config_word;
  77                 break;
  78         case 4:
  79                 field->u.dw.read = xen_pcibk_read_config_dword;
  80                 field->u.dw.write = xen_pcibk_write_config_dword;
  81                 break;
  82         default:
  83                 err = -EINVAL;
  84                 goto out;
  85         }
  86
  87         xen_pcibk_config_add_field(dev, field);
  88
  89 out:
  90         return err;
  91 }
  92
  93 int xen_pcibk_config_quirks_init(struct pci_dev *dev)
  94 {
  95         struct xen_pcibk_config_quirk *quirk;
  96         int ret = 0;
  97
  98         quirk = kzalloc(sizeof(*quirk), GFP_KERNEL);
  99         if (!quirk) {
 100                 ret = -ENOMEM;
 101                 goto out;
 102         }
 103
 104         quirk->devid.vendor = dev->vendor;
 105         quirk->devid.device = dev->device;
 106         quirk->devid.subvendor = dev->subsystem_vendor;
 107         quirk->devid.subdevice = dev->subsystem_device;
 108         quirk->devid.class = 0;
 109         quirk->devid.class_mask = 0;
 110         quirk->devid.driver_data = 0UL;
 111
 112         quirk->pdev = dev;
 113
 114         register_quirk(quirk);
 115 out:
 116         return ret;
 117 }
 118
 119 void xen_pcibk_config_field_free(struct config_field *field)
 120 {
 121         kfree(field);
 122 }
 123
 124 int xen_pcibk_config_quirk_release(struct pci_dev *dev)
 125 {
 126         struct xen_pcibk_config_quirk *quirk;
 127         int ret = 0;
 128
 129         quirk = xen_pcibk_find_quirk(dev);
 130         if (!quirk) {
 131                 ret = -ENXIO;
 132                 goto out;
 133         }
 134
 135         list_del(&quirk->quirks_list);
 136         kfree(quirk);
 137
 138 out:
 139         return ret;
 140 }