1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * PCI Backend - Handles the virtual fields found on the capability lists 4 * in the configuration space. 5 * 6 * Author: Ryan Wilson <hap9@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 14 static LIST_HEAD(capabilities); 15 struct xen_pcibk_config_capability { 16 struct list_head cap_list; 17 18 int capability; 19 20 /* If the device has the capability found above, add these fields */ 21 const struct config_field *fields; 22 }; 23 24 static const struct config_field caplist_header[] = { 25 { 26 .offset = PCI_CAP_LIST_ID, 27 .size = 2, /* encompass PCI_CAP_LIST_ID & PCI_CAP_LIST_NEXT */ 28 .u.w.read = xen_pcibk_read_config_word, 29 .u.w.write = NULL, 30 }, 31 {} 32 }; 33 34 static inline void register_capability(struct xen_pcibk_config_capability *cap) 35 { 36 list_add_tail(&cap->cap_list, &capabilities); 37 } 38 39 int xen_pcibk_config_capability_add_fields(struct pci_dev *dev) 40 { 41 int err = 0; 42 struct xen_pcibk_config_capability *cap; 43 int cap_offset; 44 45 list_for_each_entry(cap, &capabilities, cap_list) { 46 cap_offset = pci_find_capability(dev, cap->capability); 47 if (cap_offset) { 48 dev_dbg(&dev->dev, "Found capability 0x%x at 0x%x\n", 49 cap->capability, cap_offset); 50 51 err = xen_pcibk_config_add_fields_offset(dev, 52 caplist_header, 53 cap_offset); 54 if (err) 55 goto out; 56 err = xen_pcibk_config_add_fields_offset(dev, 57 cap->fields, 58 cap_offset); 59 if (err) 60 goto out; 61 } 62 } 63 64 out: 65 return err; 66 } 67 68 static int vpd_address_write(struct pci_dev *dev, int offset, u16 value, 69 void *data) 70 { 71 /* Disallow writes to the vital product data */ 72 if (value & PCI_VPD_ADDR_F) 73 return PCIBIOS_SET_FAILED; 74 else 75 return pci_write_config_word(dev, offset, value); 76 } 77 78 static const struct config_field caplist_vpd[] = { 79 { 80 .offset = PCI_VPD_ADDR, 81 .size = 2, 82 .u.w.read = xen_pcibk_read_config_word, 83 .u.w.write = vpd_address_write, 84 }, 85 { 86 .offset = PCI_VPD_DATA, 87 .size = 4, 88 .u.dw.read = xen_pcibk_read_config_dword, 89 .u.dw.write = NULL, 90 }, 91 {} 92 }; 93 94 static int pm_caps_read(struct pci_dev *dev, int offset, u16 *value, 95 void *data) 96 { 97 int err; 98 u16 real_value; 99 100 err = pci_read_config_word(dev, offset, &real_value); 101 if (err) 102 goto out; 103 104 *value = real_value & ~PCI_PM_CAP_PME_MASK; 105 106 out: 107 return err; 108 } 109 110 /* PM_OK_BITS specifies the bits that the driver domain is allowed to change. 111 * Can't allow driver domain to enable PMEs - they're shared */ 112 #define PM_OK_BITS (PCI_PM_CTRL_PME_STATUS|PCI_PM_CTRL_DATA_SEL_MASK) 113 114 static int pm_ctrl_write(struct pci_dev *dev, int offset, u16 new_value, 115 void *data) 116 { 117 int err; 118 u16 old_value; 119 pci_power_t new_state; 120 121 err = pci_read_config_word(dev, offset, &old_value); 122 if (err) 123 goto out; 124 125 new_state = (pci_power_t)(new_value & PCI_PM_CTRL_STATE_MASK); 126 127 new_value &= PM_OK_BITS; 128 if ((old_value & PM_OK_BITS) != new_value) { 129 new_value = (old_value & ~PM_OK_BITS) | new_value; 130 err = pci_write_config_word(dev, offset, new_value); 131 if (err) 132 goto out; 133 } 134 135 /* Let pci core handle the power management change */ 136 dev_dbg(&dev->dev, "set power state to %x\n", new_state); 137 err = pci_set_power_state(dev, new_state); 138 if (err) { 139 err = PCIBIOS_SET_FAILED; 140 goto out; 141 } 142 143 out: 144 return err; 145 } 146 147 /* Ensure PMEs are disabled */ 148 static void *pm_ctrl_init(struct pci_dev *dev, int offset) 149 { 150 int err; 151 u16 value; 152 153 err = pci_read_config_word(dev, offset, &value); 154 if (err) 155 goto out; 156 157 if (value & PCI_PM_CTRL_PME_ENABLE) { 158 value &= ~PCI_PM_CTRL_PME_ENABLE; 159 err = pci_write_config_word(dev, offset, value); 160 } 161 162 out: 163 return err ? ERR_PTR(err) : NULL; 164 } 165 166 static const struct config_field caplist_pm[] = { 167 { 168 .offset = PCI_PM_PMC, 169 .size = 2, 170 .u.w.read = pm_caps_read, 171 }, 172 { 173 .offset = PCI_PM_CTRL, 174 .size = 2, 175 .init = pm_ctrl_init, 176 .u.w.read = xen_pcibk_read_config_word, 177 .u.w.write = pm_ctrl_write, 178 }, 179 { 180 .offset = PCI_PM_PPB_EXTENSIONS, 181 .size = 1, 182 .u.b.read = xen_pcibk_read_config_byte, 183 }, 184 { 185 .offset = PCI_PM_DATA_REGISTER, 186 .size = 1, 187 .u.b.read = xen_pcibk_read_config_byte, 188 }, 189 {} 190 }; 191 192 static struct msi_msix_field_config { 193 u16 enable_bit; /* bit for enabling MSI/MSI-X */ 194 u16 allowed_bits; /* bits allowed to be changed */ 195 unsigned int int_type; /* interrupt type for exclusiveness check */ 196 } msi_field_config = { 197 .enable_bit = PCI_MSI_FLAGS_ENABLE, 198 .allowed_bits = PCI_MSI_FLAGS_ENABLE, 199 .int_type = INTERRUPT_TYPE_MSI, 200 }, msix_field_config = { 201 .enable_bit = PCI_MSIX_FLAGS_ENABLE, 202 .allowed_bits = PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL, 203 .int_type = INTERRUPT_TYPE_MSIX, 204 }; 205 206 static void *msi_field_init(struct pci_dev *dev, int offset) 207 { 208 return &msi_field_config; 209 } 210 211 static void *msix_field_init(struct pci_dev *dev, int offset) 212 { 213 return &msix_field_config; 214 } 215 216 static int msi_msix_flags_write(struct pci_dev *dev, int offset, u16 new_value, 217 void *data) 218 { 219 int err; 220 u16 old_value; 221 const struct msi_msix_field_config *field_config = data; 222 const struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); 223 224 if (xen_pcibk_permissive || dev_data->permissive) 225 goto write; 226 227 err = pci_read_config_word(dev, offset, &old_value); 228 if (err) 229 return err; 230 231 if (new_value == old_value) 232 return 0; 233 234 if (!dev_data->allow_interrupt_control || 235 (new_value ^ old_value) & ~field_config->allowed_bits) 236 return PCIBIOS_SET_FAILED; 237 238 if (new_value & field_config->enable_bit) { 239 /* 240 * Don't allow enabling together with other interrupt type, but do 241 * allow enabling MSI(-X) while INTx is still active to please Linuxes 242 * MSI(-X) startup sequence. It is safe to do, as according to PCI 243 * spec, device with enabled MSI(-X) shouldn't use INTx. 244 */ 245 int int_type = xen_pcibk_get_interrupt_type(dev); 246 247 if (int_type == INTERRUPT_TYPE_NONE || 248 int_type == INTERRUPT_TYPE_INTX || 249 int_type == field_config->int_type) 250 goto write; 251 return PCIBIOS_SET_FAILED; 252 } 253 254 write: 255 return pci_write_config_word(dev, offset, new_value); 256 } 257 258 static const struct config_field caplist_msix[] = { 259 { 260 .offset = PCI_MSIX_FLAGS, 261 .size = 2, 262 .init = msix_field_init, 263 .u.w.read = xen_pcibk_read_config_word, 264 .u.w.write = msi_msix_flags_write, 265 }, 266 {} 267 }; 268 269 static const struct config_field caplist_msi[] = { 270 { 271 .offset = PCI_MSI_FLAGS, 272 .size = 2, 273 .init = msi_field_init, 274 .u.w.read = xen_pcibk_read_config_word, 275 .u.w.write = msi_msix_flags_write, 276 }, 277 {} 278 }; 279 280 static struct xen_pcibk_config_capability xen_pcibk_config_capability_pm = { 281 .capability = PCI_CAP_ID_PM, 282 .fields = caplist_pm, 283 }; 284 static struct xen_pcibk_config_capability xen_pcibk_config_capability_vpd = { 285 .capability = PCI_CAP_ID_VPD, 286 .fields = caplist_vpd, 287 }; 288 static struct xen_pcibk_config_capability xen_pcibk_config_capability_msi = { 289 .capability = PCI_CAP_ID_MSI, 290 .fields = caplist_msi, 291 }; 292 static struct xen_pcibk_config_capability xen_pcibk_config_capability_msix = { 293 .capability = PCI_CAP_ID_MSIX, 294 .fields = caplist_msix, 295 }; 296 297 int xen_pcibk_config_capability_init(void) 298 { 299 register_capability(&xen_pcibk_config_capability_vpd); 300 register_capability(&xen_pcibk_config_capability_pm); 301 register_capability(&xen_pcibk_config_capability_msi); 302 register_capability(&xen_pcibk_config_capability_msix); 303 304 return 0; 305 } 306