#include <linux/delay.h> #include <linux/pci.h> #include <linux/module.h> #include <linux/sched.h> #include <linux/ioport.h> #include <linux/wait.h> #include "pci.h" /* * This interrupt-safe spinlock protects all accesses to PCI * configuration space. */ static DEFINE_SPINLOCK(pci_lock); /* * Wrappers for all PCI configuration access functions. They just check * alignment, do locking and call the low-level functions pointed to * by pci_dev->ops. */ #define PCI_byte_BAD 0 #define PCI_word_BAD (pos & 1) #define PCI_dword_BAD (pos & 3) #define PCI_OP_READ(size,type,len) \ int pci_bus_read_config_##size \ (struct pci_bus *bus, unsigned int devfn, int pos, type *value) \ { \ int res; \ unsigned long flags; \ u32 data = 0; \ if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ spin_lock_irqsave(&pci_lock, flags); \ res = bus->ops->read(bus, devfn, pos, len, &data); \ *value = (type)data; \ spin_unlock_irqrestore(&pci_lock, flags); \ return res; \ } #define PCI_OP_WRITE(size,type,len) \ int pci_bus_write_config_##size \ (struct pci_bus *bus, unsigned int devfn, int pos, type value) \ { \ int res; \ unsigned long flags; \ if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ spin_lock_irqsave(&pci_lock, flags); \ res = bus->ops->write(bus, devfn, pos, len, value); \ spin_unlock_irqrestore(&pci_lock, flags); \ return res; \ } PCI_OP_READ(byte, u8, 1) PCI_OP_READ(word, u16, 2) PCI_OP_READ(dword, u32, 4) PCI_OP_WRITE(byte, u8, 1) PCI_OP_WRITE(word, u16, 2) PCI_OP_WRITE(dword, u32, 4) EXPORT_SYMBOL(pci_bus_read_config_byte); EXPORT_SYMBOL(pci_bus_read_config_word); EXPORT_SYMBOL(pci_bus_read_config_dword); EXPORT_SYMBOL(pci_bus_write_config_byte); EXPORT_SYMBOL(pci_bus_write_config_word); EXPORT_SYMBOL(pci_bus_write_config_dword); /* * The following routines are to prevent the user from accessing PCI config * space when it's unsafe to do so. Some devices require this during BIST and * we're required to prevent it during D-state transitions. * * We have a bit per device to indicate it's blocked and a global wait queue * for callers to sleep on until devices are unblocked. */ static DECLARE_WAIT_QUEUE_HEAD(pci_ucfg_wait); static noinline void pci_wait_ucfg(struct pci_dev *dev) { DECLARE_WAITQUEUE(wait, current); __add_wait_queue(&pci_ucfg_wait, &wait); do { set_current_state(TASK_UNINTERRUPTIBLE); spin_unlock_irq(&pci_lock); schedule(); spin_lock_irq(&pci_lock); } while (dev->block_ucfg_access); __remove_wait_queue(&pci_ucfg_wait, &wait); } #define PCI_USER_READ_CONFIG(size,type) \ int pci_user_read_config_##size \ (struct pci_dev *dev, int pos, type *val) \ { \ int ret = 0; \ u32 data = -1; \ if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ spin_lock_irq(&pci_lock); \ if (unlikely(dev->block_ucfg_access)) pci_wait_ucfg(dev); \ ret = dev->bus->ops->read(dev->bus, dev->devfn, \ pos, sizeof(type), &data); \ spin_unlock_irq(&pci_lock); \ *val = (type)data; \ return ret; \ } #define PCI_USER_WRITE_CONFIG(size,type) \ int pci_user_write_config_##size \ (struct pci_dev *dev, int pos, type val) \ { \ int ret = -EIO; \ if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ spin_lock_irq(&pci_lock); \ if (unlikely(dev->block_ucfg_access)) pci_wait_ucfg(dev); \ ret = dev->bus->ops->write(dev->bus, dev->devfn, \ pos, sizeof(type), val); \ spin_unlock_irq(&pci_lock); \ return ret; \ } PCI_USER_READ_CONFIG(byte, u8) PCI_USER_READ_CONFIG(word, u16) PCI_USER_READ_CONFIG(dword, u32) PCI_USER_WRITE_CONFIG(byte, u8) PCI_USER_WRITE_CONFIG(word, u16) PCI_USER_WRITE_CONFIG(dword, u32) /* VPD access through PCI 2.2+ VPD capability */ #define PCI_VPD_PCI22_SIZE (PCI_VPD_ADDR_MASK + 1) struct pci_vpd_pci22 { struct pci_vpd base; spinlock_t lock; /* controls access to hardware and the flags */ u8 cap; bool busy; bool flag; /* value of F bit to wait for */ }; /* Wait for last operation to complete */ static int pci_vpd_pci22_wait(struct pci_dev *dev) { struct pci_vpd_pci22 *vpd = container_of(dev->vpd, struct pci_vpd_pci22, base); u16 flag, status; int wait; int ret; if (!vpd->busy) return 0; flag = vpd->flag ? PCI_VPD_ADDR_F : 0; wait = vpd->flag ? 10 : 1000; /* read: 100 us; write: 10 ms */ for (;;) { ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR, &status); if (ret < 0) return ret; if ((status & PCI_VPD_ADDR_F) == flag) { vpd->busy = false; return 0; } if (wait-- == 0) return -ETIMEDOUT; udelay(10); } } static int pci_vpd_pci22_read(struct pci_dev *dev, int pos, int size, char *buf) { struct pci_vpd_pci22 *vpd = container_of(dev->vpd, struct pci_vpd_pci22, base); u32 val; int ret; int begin, end, i; if (pos < 0 || pos > vpd->base.len || size > vpd->base.len - pos) return -EINVAL; if (size == 0) return 0; spin_lock_irq(&vpd->lock); ret = pci_vpd_pci22_wait(dev); if (ret < 0) goto out; ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR, pos & ~3); if (ret < 0) goto out; vpd->busy = true; vpd->flag = 1; ret = pci_vpd_pci22_wait(dev); if (ret < 0) goto out; ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, &val); out: spin_unlock_irq(&vpd->lock); if (ret < 0) return ret; /* Convert to bytes */ begin = pos & 3; end = min(4, begin + size); for (i = 0; i < end; ++i) { if (i >= begin) *buf++ = val; val >>= 8; } return end - begin; } static int pci_vpd_pci22_write(struct pci_dev *dev, int pos, int size, const char *buf) { struct pci_vpd_pci22 *vpd = container_of(dev->vpd, struct pci_vpd_pci22, base); u32 val; int ret; if (pos < 0 || pos > vpd->base.len || pos & 3 || size > vpd->base.len - pos || size < 4) return -EINVAL; val = (u8) *buf++; val |= ((u8) *buf++) << 8; val |= ((u8) *buf++) << 16; val |= ((u32)(u8) *buf++) << 24; spin_lock_irq(&vpd->lock); ret = pci_vpd_pci22_wait(dev); if (ret < 0) goto out; ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA, val); if (ret < 0) goto out; ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR, pos | PCI_VPD_ADDR_F); if (ret < 0) goto out; vpd->busy = true; vpd->flag = 0; ret = pci_vpd_pci22_wait(dev); out: spin_unlock_irq(&vpd->lock); if (ret < 0) return ret; return 4; } static void pci_vpd_pci22_release(struct pci_dev *dev) { kfree(container_of(dev->vpd, struct pci_vpd_pci22, base)); } static struct pci_vpd_ops pci_vpd_pci22_ops = { .read = pci_vpd_pci22_read, .write = pci_vpd_pci22_write, .release = pci_vpd_pci22_release, }; int pci_vpd_pci22_init(struct pci_dev *dev) { struct pci_vpd_pci22 *vpd; u8 cap; cap = pci_find_capability(dev, PCI_CAP_ID_VPD); if (!cap) return -ENODEV; vpd = kzalloc(sizeof(*vpd), GFP_ATOMIC); if (!vpd) return -ENOMEM; vpd->base.len = PCI_VPD_PCI22_SIZE; vpd->base.ops = &pci_vpd_pci22_ops; spin_lock_init(&vpd->lock); vpd->cap = cap; vpd->busy = false; dev->vpd = &vpd->base; return 0; } /** * pci_block_user_cfg_access - Block userspace PCI config reads/writes * @dev: pci device struct * * When user access is blocked, any reads or writes to config space will * sleep until access is unblocked again. We don't allow nesting of * block/unblock calls. */ void pci_block_user_cfg_access(struct pci_dev *dev) { unsigned long flags; int was_blocked; spin_lock_irqsave(&pci_lock, flags); was_blocked = dev->block_ucfg_access; dev->block_ucfg_access = 1; spin_unlock_irqrestore(&pci_lock, flags); /* If we BUG() inside the pci_lock, we're guaranteed to hose * the machine */ BUG_ON(was_blocked); } EXPORT_SYMBOL_GPL(pci_block_user_cfg_access); /** * pci_unblock_user_cfg_access - Unblock userspace PCI config reads/writes * @dev: pci device struct * * This function allows userspace PCI config accesses to resume. */ void pci_unblock_user_cfg_access(struct pci_dev *dev) { unsigned long flags; spin_lock_irqsave(&pci_lock, flags); /* This indicates a problem in the caller, but we don't need * to kill them, unlike a double-block above. */ WARN_ON(!dev->block_ucfg_access); dev->block_ucfg_access = 0; wake_up_all(&pci_ucfg_wait); spin_unlock_irqrestore(&pci_lock, flags); } EXPORT_SYMBOL_GPL(pci_unblock_user_cfg_access);