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 #define dev_fmt(fmt) DRV_NAME ": " fmt
  10
  11 #include <linux/kernel.h>
  12 #include <linux/pci.h>
  13 #include "pciback.h"
  14 #include "conf_space.h"
  15 #include "conf_space_quirks.h"
  16
  17 LIST_HEAD(xen_pcibk_quirks);
  18 static inline const struct pci_device_id *
  19 match_one_device(const struct pci_device_id *id, const struct pci_dev *dev)
  20 {
  21         if ((id->vendor == PCI_ANY_ID || id->vendor == dev->vendor) &&
  22             (id->device == PCI_ANY_ID || id->device == dev->device) &&
  23             (id->subvendor == PCI_ANY_ID ||
  24                                 id->subvendor == dev->subsystem_vendor) &&
  25             (id->subdevice == PCI_ANY_ID ||
  26                                 id->subdevice == dev->subsystem_device) &&
  27             !((id->class ^ dev->class) & id->class_mask))
  28                 return id;
  29         return NULL;
  30 }
  31
  32 static struct xen_pcibk_config_quirk *xen_pcibk_find_quirk(struct pci_dev *dev)
  33 {
  34         struct xen_pcibk_config_quirk *tmp_quirk;
  35
  36         list_for_each_entry(tmp_quirk, &xen_pcibk_quirks, quirks_list)
  37                 if (match_one_device(&tmp_quirk->devid, dev) != NULL)
  38                         goto out;
  39         tmp_quirk = NULL;
  40         dev_printk(KERN_DEBUG, &dev->dev,
  41                    "quirk didn't match any device known\n");
  42 out:
  43         return tmp_quirk;
  44 }
  45
  46 static inline void register_quirk(struct xen_pcibk_config_quirk *quirk)
  47 {
  48         list_add_tail(&quirk->quirks_list, &xen_pcibk_quirks);
  49 }
  50
  51 int xen_pcibk_field_is_dup(struct pci_dev *dev, unsigned int reg)
  52 {
  53         int ret = 0;
  54         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
  55         struct config_field_entry *cfg_entry;
  56
  57         list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
  58                 if (OFFSET(cfg_entry) == reg) {
  59                         ret = 1;
  60                         break;
  61                 }
  62         }
  63         return ret;
  64 }
  65
  66 int xen_pcibk_config_quirks_add_field(struct pci_dev *dev, struct config_field
  67                                     *field)
  68 {
  69         int err = 0;
  70
  71         switch (field->size) {
  72         case 1:
  73                 field->u.b.read = xen_pcibk_read_config_byte;
  74                 field->u.b.write = xen_pcibk_write_config_byte;
  75                 break;
  76         case 2:
  77                 field->u.w.read = xen_pcibk_read_config_word;
  78                 field->u.w.write = xen_pcibk_write_config_word;
  79                 break;
  80         case 4:
  81                 field->u.dw.read = xen_pcibk_read_config_dword;
  82                 field->u.dw.write = xen_pcibk_write_config_dword;
  83                 break;
  84         default:
  85                 err = -EINVAL;
  86                 goto out;
  87         }
  88
  89         xen_pcibk_config_add_field(dev, field);
  90
  91 out:
  92         return err;
  93 }
  94
  95 int xen_pcibk_config_quirks_init(struct pci_dev *dev)
  96 {
  97         struct xen_pcibk_config_quirk *quirk;
  98         int ret = 0;
  99
 100         quirk = kzalloc(sizeof(*quirk), GFP_KERNEL);
 101         if (!quirk) {
 102                 ret = -ENOMEM;
 103                 goto out;
 104         }
 105
 106         quirk->devid.vendor = dev->vendor;
 107         quirk->devid.device = dev->device;
 108         quirk->devid.subvendor = dev->subsystem_vendor;
 109         quirk->devid.subdevice = dev->subsystem_device;
 110         quirk->devid.class = 0;
 111         quirk->devid.class_mask = 0;
 112         quirk->devid.driver_data = 0UL;
 113
 114         quirk->pdev = dev;
 115
 116         register_quirk(quirk);
 117 out:
 118         return ret;
 119 }
 120
 121 void xen_pcibk_config_field_free(struct config_field *field)
 122 {
 123         kfree(field);
 124 }
 125
 126 int xen_pcibk_config_quirk_release(struct pci_dev *dev)
 127 {
 128         struct xen_pcibk_config_quirk *quirk;
 129         int ret = 0;
 130
 131         quirk = xen_pcibk_find_quirk(dev);
 132         if (!quirk) {
 133                 ret = -ENXIO;
 134                 goto out;
 135         }
 136
 137         list_del(&quirk->quirks_list);
 138         kfree(quirk);
 139
 140 out:
 141         return ret;
 142 }