1 #include <linux/delay.h> 2 #include <linux/pci.h> 3 #include <linux/module.h> 4 #include <linux/sched.h> 5 #include <linux/ioport.h> 6 #include <linux/wait.h> 7 8 #include "pci.h" 9 10 /* 11 * This interrupt-safe spinlock protects all accesses to PCI 12 * configuration space. 13 */ 14 15 static DEFINE_SPINLOCK(pci_lock); 16 17 /* 18 * Wrappers for all PCI configuration access functions. They just check 19 * alignment, do locking and call the low-level functions pointed to 20 * by pci_dev->ops. 21 */ 22 23 #define PCI_byte_BAD 0 24 #define PCI_word_BAD (pos & 1) 25 #define PCI_dword_BAD (pos & 3) 26 27 #define PCI_OP_READ(size,type,len) \ 28 int pci_bus_read_config_##size \ 29 (struct pci_bus *bus, unsigned int devfn, int pos, type *value) \ 30 { \ 31 int res; \ 32 unsigned long flags; \ 33 u32 data = 0; \ 34 if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ 35 spin_lock_irqsave(&pci_lock, flags); \ 36 res = bus->ops->read(bus, devfn, pos, len, &data); \ 37 *value = (type)data; \ 38 spin_unlock_irqrestore(&pci_lock, flags); \ 39 return res; \ 40 } 41 42 #define PCI_OP_WRITE(size,type,len) \ 43 int pci_bus_write_config_##size \ 44 (struct pci_bus *bus, unsigned int devfn, int pos, type value) \ 45 { \ 46 int res; \ 47 unsigned long flags; \ 48 if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ 49 spin_lock_irqsave(&pci_lock, flags); \ 50 res = bus->ops->write(bus, devfn, pos, len, value); \ 51 spin_unlock_irqrestore(&pci_lock, flags); \ 52 return res; \ 53 } 54 55 PCI_OP_READ(byte, u8, 1) 56 PCI_OP_READ(word, u16, 2) 57 PCI_OP_READ(dword, u32, 4) 58 PCI_OP_WRITE(byte, u8, 1) 59 PCI_OP_WRITE(word, u16, 2) 60 PCI_OP_WRITE(dword, u32, 4) 61 62 EXPORT_SYMBOL(pci_bus_read_config_byte); 63 EXPORT_SYMBOL(pci_bus_read_config_word); 64 EXPORT_SYMBOL(pci_bus_read_config_dword); 65 EXPORT_SYMBOL(pci_bus_write_config_byte); 66 EXPORT_SYMBOL(pci_bus_write_config_word); 67 EXPORT_SYMBOL(pci_bus_write_config_dword); 68 69 /* 70 * The following routines are to prevent the user from accessing PCI config 71 * space when it's unsafe to do so. Some devices require this during BIST and 72 * we're required to prevent it during D-state transitions. 73 * 74 * We have a bit per device to indicate it's blocked and a global wait queue 75 * for callers to sleep on until devices are unblocked. 76 */ 77 static DECLARE_WAIT_QUEUE_HEAD(pci_ucfg_wait); 78 79 static noinline void pci_wait_ucfg(struct pci_dev *dev) 80 { 81 DECLARE_WAITQUEUE(wait, current); 82 83 __add_wait_queue(&pci_ucfg_wait, &wait); 84 do { 85 set_current_state(TASK_UNINTERRUPTIBLE); 86 spin_unlock_irq(&pci_lock); 87 schedule(); 88 spin_lock_irq(&pci_lock); 89 } while (dev->block_ucfg_access); 90 __remove_wait_queue(&pci_ucfg_wait, &wait); 91 } 92 93 #define PCI_USER_READ_CONFIG(size,type) \ 94 int pci_user_read_config_##size \ 95 (struct pci_dev *dev, int pos, type *val) \ 96 { \ 97 int ret = 0; \ 98 u32 data = -1; \ 99 if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ 100 spin_lock_irq(&pci_lock); \ 101 if (unlikely(dev->block_ucfg_access)) pci_wait_ucfg(dev); \ 102 ret = dev->bus->ops->read(dev->bus, dev->devfn, \ 103 pos, sizeof(type), &data); \ 104 spin_unlock_irq(&pci_lock); \ 105 *val = (type)data; \ 106 return ret; \ 107 } 108 109 #define PCI_USER_WRITE_CONFIG(size,type) \ 110 int pci_user_write_config_##size \ 111 (struct pci_dev *dev, int pos, type val) \ 112 { \ 113 int ret = -EIO; \ 114 if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ 115 spin_lock_irq(&pci_lock); \ 116 if (unlikely(dev->block_ucfg_access)) pci_wait_ucfg(dev); \ 117 ret = dev->bus->ops->write(dev->bus, dev->devfn, \ 118 pos, sizeof(type), val); \ 119 spin_unlock_irq(&pci_lock); \ 120 return ret; \ 121 } 122 123 PCI_USER_READ_CONFIG(byte, u8) 124 PCI_USER_READ_CONFIG(word, u16) 125 PCI_USER_READ_CONFIG(dword, u32) 126 PCI_USER_WRITE_CONFIG(byte, u8) 127 PCI_USER_WRITE_CONFIG(word, u16) 128 PCI_USER_WRITE_CONFIG(dword, u32) 129 130 /* VPD access through PCI 2.2+ VPD capability */ 131 132 #define PCI_VPD_PCI22_SIZE (PCI_VPD_ADDR_MASK + 1) 133 134 struct pci_vpd_pci22 { 135 struct pci_vpd base; 136 spinlock_t lock; /* controls access to hardware and the flags */ 137 u8 cap; 138 bool busy; 139 bool flag; /* value of F bit to wait for */ 140 }; 141 142 /* Wait for last operation to complete */ 143 static int pci_vpd_pci22_wait(struct pci_dev *dev) 144 { 145 struct pci_vpd_pci22 *vpd = 146 container_of(dev->vpd, struct pci_vpd_pci22, base); 147 u16 flag, status; 148 int wait; 149 int ret; 150 151 if (!vpd->busy) 152 return 0; 153 154 flag = vpd->flag ? PCI_VPD_ADDR_F : 0; 155 wait = vpd->flag ? 10 : 1000; /* read: 100 us; write: 10 ms */ 156 for (;;) { 157 ret = pci_user_read_config_word(dev, 158 vpd->cap + PCI_VPD_ADDR, 159 &status); 160 if (ret < 0) 161 return ret; 162 if ((status & PCI_VPD_ADDR_F) == flag) { 163 vpd->busy = false; 164 return 0; 165 } 166 if (wait-- == 0) 167 return -ETIMEDOUT; 168 udelay(10); 169 } 170 } 171 172 static int pci_vpd_pci22_read(struct pci_dev *dev, int pos, int size, 173 char *buf) 174 { 175 struct pci_vpd_pci22 *vpd = 176 container_of(dev->vpd, struct pci_vpd_pci22, base); 177 u32 val; 178 int ret; 179 int begin, end, i; 180 181 if (pos < 0 || pos > vpd->base.len || size > vpd->base.len - pos) 182 return -EINVAL; 183 if (size == 0) 184 return 0; 185 186 spin_lock_irq(&vpd->lock); 187 ret = pci_vpd_pci22_wait(dev); 188 if (ret < 0) 189 goto out; 190 ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR, 191 pos & ~3); 192 if (ret < 0) 193 goto out; 194 vpd->busy = true; 195 vpd->flag = 1; 196 ret = pci_vpd_pci22_wait(dev); 197 if (ret < 0) 198 goto out; 199 ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, 200 &val); 201 out: 202 spin_unlock_irq(&vpd->lock); 203 if (ret < 0) 204 return ret; 205 206 /* Convert to bytes */ 207 begin = pos & 3; 208 end = min(4, begin + size); 209 for (i = 0; i < end; ++i) { 210 if (i >= begin) 211 *buf++ = val; 212 val >>= 8; 213 } 214 return end - begin; 215 } 216 217 static int pci_vpd_pci22_write(struct pci_dev *dev, int pos, int size, 218 const char *buf) 219 { 220 struct pci_vpd_pci22 *vpd = 221 container_of(dev->vpd, struct pci_vpd_pci22, base); 222 u32 val; 223 int ret; 224 225 if (pos < 0 || pos > vpd->base.len || pos & 3 || 226 size > vpd->base.len - pos || size < 4) 227 return -EINVAL; 228 229 val = (u8) *buf++; 230 val |= ((u8) *buf++) << 8; 231 val |= ((u8) *buf++) << 16; 232 val |= ((u32)(u8) *buf++) << 24; 233 234 spin_lock_irq(&vpd->lock); 235 ret = pci_vpd_pci22_wait(dev); 236 if (ret < 0) 237 goto out; 238 ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA, 239 val); 240 if (ret < 0) 241 goto out; 242 ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR, 243 pos | PCI_VPD_ADDR_F); 244 if (ret < 0) 245 goto out; 246 vpd->busy = true; 247 vpd->flag = 0; 248 ret = pci_vpd_pci22_wait(dev); 249 out: 250 spin_unlock_irq(&vpd->lock); 251 if (ret < 0) 252 return ret; 253 254 return 4; 255 } 256 257 static void pci_vpd_pci22_release(struct pci_dev *dev) 258 { 259 kfree(container_of(dev->vpd, struct pci_vpd_pci22, base)); 260 } 261 262 static struct pci_vpd_ops pci_vpd_pci22_ops = { 263 .read = pci_vpd_pci22_read, 264 .write = pci_vpd_pci22_write, 265 .release = pci_vpd_pci22_release, 266 }; 267 268 int pci_vpd_pci22_init(struct pci_dev *dev) 269 { 270 struct pci_vpd_pci22 *vpd; 271 u8 cap; 272 273 cap = pci_find_capability(dev, PCI_CAP_ID_VPD); 274 if (!cap) 275 return -ENODEV; 276 vpd = kzalloc(sizeof(*vpd), GFP_ATOMIC); 277 if (!vpd) 278 return -ENOMEM; 279 280 vpd->base.len = PCI_VPD_PCI22_SIZE; 281 vpd->base.ops = &pci_vpd_pci22_ops; 282 spin_lock_init(&vpd->lock); 283 vpd->cap = cap; 284 vpd->busy = false; 285 dev->vpd = &vpd->base; 286 return 0; 287 } 288 289 /** 290 * pci_block_user_cfg_access - Block userspace PCI config reads/writes 291 * @dev: pci device struct 292 * 293 * When user access is blocked, any reads or writes to config space will 294 * sleep until access is unblocked again. We don't allow nesting of 295 * block/unblock calls. 296 */ 297 void pci_block_user_cfg_access(struct pci_dev *dev) 298 { 299 unsigned long flags; 300 int was_blocked; 301 302 spin_lock_irqsave(&pci_lock, flags); 303 was_blocked = dev->block_ucfg_access; 304 dev->block_ucfg_access = 1; 305 spin_unlock_irqrestore(&pci_lock, flags); 306 307 /* If we BUG() inside the pci_lock, we're guaranteed to hose 308 * the machine */ 309 BUG_ON(was_blocked); 310 } 311 EXPORT_SYMBOL_GPL(pci_block_user_cfg_access); 312 313 /** 314 * pci_unblock_user_cfg_access - Unblock userspace PCI config reads/writes 315 * @dev: pci device struct 316 * 317 * This function allows userspace PCI config accesses to resume. 318 */ 319 void pci_unblock_user_cfg_access(struct pci_dev *dev) 320 { 321 unsigned long flags; 322 323 spin_lock_irqsave(&pci_lock, flags); 324 325 /* This indicates a problem in the caller, but we don't need 326 * to kill them, unlike a double-block above. */ 327 WARN_ON(!dev->block_ucfg_access); 328 329 dev->block_ucfg_access = 0; 330 wake_up_all(&pci_ucfg_wait); 331 spin_unlock_irqrestore(&pci_lock, flags); 332 } 333 EXPORT_SYMBOL_GPL(pci_unblock_user_cfg_access); 334