#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); /** * pci_read_vpd - Read one entry from Vital Product Data * @dev: pci device struct * @pos: offset in vpd space * @count: number of bytes to read * @buf: pointer to where to store result * */ ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf) { if (!dev->vpd || !dev->vpd->ops) return -ENODEV; return dev->vpd->ops->read(dev, pos, count, buf); } EXPORT_SYMBOL(pci_read_vpd); /** * pci_write_vpd - Write entry to Vital Product Data * @dev: pci device struct * @pos: offset in vpd space * @count: number of bytes to write * @buf: buffer containing write data * */ ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf) { if (!dev->vpd || !dev->vpd->ops) return -ENODEV; return dev->vpd->ops->write(dev, pos, count, buf); } EXPORT_SYMBOL(pci_write_vpd); /* * 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; struct mutex lock; u16 flag; bool busy; u8 cap; }; /* * Wait for last operation to complete. * This code has to spin since there is no other notification from the PCI * hardware. Since the VPD is often implemented by serial attachment to an * EEPROM, it may take many milliseconds 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); unsigned long timeout = jiffies + HZ/20 + 2; u16 status; int ret; if (!vpd->busy) return 0; for (;;) { ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR, &status); if (ret) return ret; if ((status & PCI_VPD_ADDR_F) == vpd->flag) { vpd->busy = false; return 0; } if (time_after(jiffies, timeout)) return -ETIMEDOUT; if (fatal_signal_pending(current)) return -EINTR; if (!cond_resched()) udelay(10); } } static ssize_t pci_vpd_pci22_read(struct pci_dev *dev, loff_t pos, size_t count, void *arg) { struct pci_vpd_pci22 *vpd = container_of(dev->vpd, struct pci_vpd_pci22, base); int ret; loff_t end = pos + count; u8 *buf = arg; if (pos < 0 || pos > vpd->base.len || end > vpd->base.len) return -EINVAL; if (mutex_lock_killable(&vpd->lock)) return -EINTR; ret = pci_vpd_pci22_wait(dev); if (ret < 0) goto out; while (pos < end) { u32 val; unsigned int i, skip; ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR, pos & ~3); if (ret < 0) break; vpd->busy = true; vpd->flag = PCI_VPD_ADDR_F; ret = pci_vpd_pci22_wait(dev); if (ret < 0) break; ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, &val); if (ret < 0) break; skip = pos & 3; for (i = 0; i < sizeof(u32); i++) { if (i >= skip) { *buf++ = val; if (++pos == end) break; } val >>= 8; } } out: mutex_unlock(&vpd->lock); return ret ? ret : count; } static ssize_t pci_vpd_pci22_write(struct pci_dev *dev, loff_t pos, size_t count, const void *arg) { struct pci_vpd_pci22 *vpd = container_of(dev->vpd, struct pci_vpd_pci22, base); const u8 *buf = arg; loff_t end = pos + count; int ret = 0; if (pos < 0 || (pos & 3) || (count & 3) || end > vpd->base.len) return -EINVAL; if (mutex_lock_killable(&vpd->lock)) return -EINTR; ret = pci_vpd_pci22_wait(dev); if (ret < 0) goto out; while (pos < end) { u32 val; val = *buf++; val |= *buf++ << 8; val |= *buf++ << 16; val |= *buf++ << 24; ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA, val); if (ret < 0) break; ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR, pos | PCI_VPD_ADDR_F); if (ret < 0) break; vpd->busy = true; vpd->flag = 0; ret = pci_vpd_pci22_wait(dev); pos += sizeof(u32); } out: mutex_unlock(&vpd->lock); return ret ? ret : count; } static void pci_vpd_pci22_release(struct pci_dev *dev) { kfree(container_of(dev->vpd, struct pci_vpd_pci22, base)); } static const 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; mutex_init(&vpd->lock); vpd->cap = cap; vpd->busy = false; dev->vpd = &vpd->base; return 0; } /** * pci_vpd_truncate - Set available Vital Product Data size * @dev: pci device struct * @size: available memory in bytes * * Adjust size of available VPD area. */ int pci_vpd_truncate(struct pci_dev *dev, size_t size) { if (!dev->vpd) return -EINVAL; /* limited by the access method */ if (size > dev->vpd->len) return -EINVAL; dev->vpd->len = size; if (dev->vpd->attr) dev->vpd->attr->size = size; return 0; } EXPORT_SYMBOL(pci_vpd_truncate); /** * 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);