1 #include <linux/pci.h> 2 #include <linux/module.h> 3 #include <linux/sched.h> 4 #include <linux/ioport.h> 5 #include <linux/wait.h> 6 7 #include "pci.h" 8 9 /* 10 * This interrupt-safe spinlock protects all accesses to PCI 11 * configuration space. 12 */ 13 14 static DEFINE_SPINLOCK(pci_lock); 15 16 /* 17 * Wrappers for all PCI configuration access functions. They just check 18 * alignment, do locking and call the low-level functions pointed to 19 * by pci_dev->ops. 20 */ 21 22 #define PCI_byte_BAD 0 23 #define PCI_word_BAD (pos & 1) 24 #define PCI_dword_BAD (pos & 3) 25 26 #define PCI_OP_READ(size,type,len) \ 27 int pci_bus_read_config_##size \ 28 (struct pci_bus *bus, unsigned int devfn, int pos, type *value) \ 29 { \ 30 int res; \ 31 unsigned long flags; \ 32 u32 data = 0; \ 33 if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ 34 spin_lock_irqsave(&pci_lock, flags); \ 35 res = bus->ops->read(bus, devfn, pos, len, &data); \ 36 *value = (type)data; \ 37 spin_unlock_irqrestore(&pci_lock, flags); \ 38 return res; \ 39 } 40 41 #define PCI_OP_WRITE(size,type,len) \ 42 int pci_bus_write_config_##size \ 43 (struct pci_bus *bus, unsigned int devfn, int pos, type value) \ 44 { \ 45 int res; \ 46 unsigned long flags; \ 47 if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ 48 spin_lock_irqsave(&pci_lock, flags); \ 49 res = bus->ops->write(bus, devfn, pos, len, value); \ 50 spin_unlock_irqrestore(&pci_lock, flags); \ 51 return res; \ 52 } 53 54 PCI_OP_READ(byte, u8, 1) 55 PCI_OP_READ(word, u16, 2) 56 PCI_OP_READ(dword, u32, 4) 57 PCI_OP_WRITE(byte, u8, 1) 58 PCI_OP_WRITE(word, u16, 2) 59 PCI_OP_WRITE(dword, u32, 4) 60 61 EXPORT_SYMBOL(pci_bus_read_config_byte); 62 EXPORT_SYMBOL(pci_bus_read_config_word); 63 EXPORT_SYMBOL(pci_bus_read_config_dword); 64 EXPORT_SYMBOL(pci_bus_write_config_byte); 65 EXPORT_SYMBOL(pci_bus_write_config_word); 66 EXPORT_SYMBOL(pci_bus_write_config_dword); 67 68 /* 69 * The following routines are to prevent the user from accessing PCI config 70 * space when it's unsafe to do so. Some devices require this during BIST and 71 * we're required to prevent it during D-state transitions. 72 * 73 * We have a bit per device to indicate it's blocked and a global wait queue 74 * for callers to sleep on until devices are unblocked. 75 */ 76 static DECLARE_WAIT_QUEUE_HEAD(pci_ucfg_wait); 77 78 static noinline void pci_wait_ucfg(struct pci_dev *dev) 79 { 80 DECLARE_WAITQUEUE(wait, current); 81 82 __add_wait_queue(&pci_ucfg_wait, &wait); 83 do { 84 set_current_state(TASK_UNINTERRUPTIBLE); 85 spin_unlock_irq(&pci_lock); 86 schedule(); 87 spin_lock_irq(&pci_lock); 88 } while (dev->block_ucfg_access); 89 __remove_wait_queue(&pci_ucfg_wait, &wait); 90 } 91 92 #define PCI_USER_READ_CONFIG(size,type) \ 93 int pci_user_read_config_##size \ 94 (struct pci_dev *dev, int pos, type *val) \ 95 { \ 96 int ret = 0; \ 97 u32 data = -1; \ 98 if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ 99 spin_lock_irq(&pci_lock); \ 100 if (unlikely(dev->block_ucfg_access)) pci_wait_ucfg(dev); \ 101 ret = dev->bus->ops->read(dev->bus, dev->devfn, \ 102 pos, sizeof(type), &data); \ 103 spin_unlock_irq(&pci_lock); \ 104 *val = (type)data; \ 105 return ret; \ 106 } 107 108 #define PCI_USER_WRITE_CONFIG(size,type) \ 109 int pci_user_write_config_##size \ 110 (struct pci_dev *dev, int pos, type val) \ 111 { \ 112 int ret = -EIO; \ 113 if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ 114 spin_lock_irq(&pci_lock); \ 115 if (unlikely(dev->block_ucfg_access)) pci_wait_ucfg(dev); \ 116 ret = dev->bus->ops->write(dev->bus, dev->devfn, \ 117 pos, sizeof(type), val); \ 118 spin_unlock_irq(&pci_lock); \ 119 return ret; \ 120 } 121 122 PCI_USER_READ_CONFIG(byte, u8) 123 PCI_USER_READ_CONFIG(word, u16) 124 PCI_USER_READ_CONFIG(dword, u32) 125 PCI_USER_WRITE_CONFIG(byte, u8) 126 PCI_USER_WRITE_CONFIG(word, u16) 127 PCI_USER_WRITE_CONFIG(dword, u32) 128 129 /** 130 * pci_block_user_cfg_access - Block userspace PCI config reads/writes 131 * @dev: pci device struct 132 * 133 * When user access is blocked, any reads or writes to config space will 134 * sleep until access is unblocked again. We don't allow nesting of 135 * block/unblock calls. 136 */ 137 void pci_block_user_cfg_access(struct pci_dev *dev) 138 { 139 unsigned long flags; 140 int was_blocked; 141 142 spin_lock_irqsave(&pci_lock, flags); 143 was_blocked = dev->block_ucfg_access; 144 dev->block_ucfg_access = 1; 145 spin_unlock_irqrestore(&pci_lock, flags); 146 147 /* If we BUG() inside the pci_lock, we're guaranteed to hose 148 * the machine */ 149 BUG_ON(was_blocked); 150 } 151 EXPORT_SYMBOL_GPL(pci_block_user_cfg_access); 152 153 /** 154 * pci_unblock_user_cfg_access - Unblock userspace PCI config reads/writes 155 * @dev: pci device struct 156 * 157 * This function allows userspace PCI config accesses to resume. 158 */ 159 void pci_unblock_user_cfg_access(struct pci_dev *dev) 160 { 161 unsigned long flags; 162 163 spin_lock_irqsave(&pci_lock, flags); 164 165 /* This indicates a problem in the caller, but we don't need 166 * to kill them, unlike a double-block above. */ 167 WARN_ON(!dev->block_ucfg_access); 168 169 dev->block_ucfg_access = 0; 170 wake_up_all(&pci_ucfg_wait); 171 spin_unlock_irqrestore(&pci_lock, flags); 172 } 173 EXPORT_SYMBOL_GPL(pci_unblock_user_cfg_access); 174