diff options
Diffstat (limited to 'drivers/pci/access.c')
| -rw-r--r-- | drivers/pci/access.c | 589 |
1 files changed, 589 insertions, 0 deletions
diff --git a/drivers/pci/access.c b/drivers/pci/access.c new file mode 100644 index 000000000..98ee5f05f --- /dev/null +++ b/drivers/pci/access.c @@ -0,0 +1,589 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/pci.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/ioport.h> +#include <linux/wait.h> + +#include "pci.h" + +/* + * This interrupt-safe spinlock protects all accesses to PCI + * configuration space. + */ + +DEFINE_RAW_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) + +#ifdef CONFIG_PCI_LOCKLESS_CONFIG +# define pci_lock_config(f) do { (void)(f); } while (0) +# define pci_unlock_config(f) do { (void)(f); } while (0) +#else +# define pci_lock_config(f) raw_spin_lock_irqsave(&pci_lock, f) +# define pci_unlock_config(f) raw_spin_unlock_irqrestore(&pci_lock, f) +#endif + +#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; \ + pci_lock_config(flags); \ + res = bus->ops->read(bus, devfn, pos, len, &data); \ + *value = (type)data; \ + pci_unlock_config(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; \ + pci_lock_config(flags); \ + res = bus->ops->write(bus, devfn, pos, len, value); \ + pci_unlock_config(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); + +int pci_generic_config_read(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 *val) +{ + void __iomem *addr; + + addr = bus->ops->map_bus(bus, devfn, where); + if (!addr) { + *val = ~0; + return PCIBIOS_DEVICE_NOT_FOUND; + } + + if (size == 1) + *val = readb(addr); + else if (size == 2) + *val = readw(addr); + else + *val = readl(addr); + + return PCIBIOS_SUCCESSFUL; +} +EXPORT_SYMBOL_GPL(pci_generic_config_read); + +int pci_generic_config_write(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 val) +{ + void __iomem *addr; + + addr = bus->ops->map_bus(bus, devfn, where); + if (!addr) + return PCIBIOS_DEVICE_NOT_FOUND; + + if (size == 1) + writeb(val, addr); + else if (size == 2) + writew(val, addr); + else + writel(val, addr); + + return PCIBIOS_SUCCESSFUL; +} +EXPORT_SYMBOL_GPL(pci_generic_config_write); + +int pci_generic_config_read32(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 *val) +{ + void __iomem *addr; + + addr = bus->ops->map_bus(bus, devfn, where & ~0x3); + if (!addr) { + *val = ~0; + return PCIBIOS_DEVICE_NOT_FOUND; + } + + *val = readl(addr); + + if (size <= 2) + *val = (*val >> (8 * (where & 3))) & ((1 << (size * 8)) - 1); + + return PCIBIOS_SUCCESSFUL; +} +EXPORT_SYMBOL_GPL(pci_generic_config_read32); + +int pci_generic_config_write32(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 val) +{ + void __iomem *addr; + u32 mask, tmp; + + addr = bus->ops->map_bus(bus, devfn, where & ~0x3); + if (!addr) + return PCIBIOS_DEVICE_NOT_FOUND; + + if (size == 4) { + writel(val, addr); + return PCIBIOS_SUCCESSFUL; + } + + /* + * In general, hardware that supports only 32-bit writes on PCI is + * not spec-compliant. For example, software may perform a 16-bit + * write. If the hardware only supports 32-bit accesses, we must + * do a 32-bit read, merge in the 16 bits we intend to write, + * followed by a 32-bit write. If the 16 bits we *don't* intend to + * write happen to have any RW1C (write-one-to-clear) bits set, we + * just inadvertently cleared something we shouldn't have. + */ + if (!bus->unsafe_warn) { + dev_warn(&bus->dev, "%d-byte config write to %04x:%02x:%02x.%d offset %#x may corrupt adjacent RW1C bits\n", + size, pci_domain_nr(bus), bus->number, + PCI_SLOT(devfn), PCI_FUNC(devfn), where); + bus->unsafe_warn = 1; + } + + mask = ~(((1 << (size * 8)) - 1) << ((where & 0x3) * 8)); + tmp = readl(addr) & mask; + tmp |= val << ((where & 0x3) * 8); + writel(tmp, addr); + + return PCIBIOS_SUCCESSFUL; +} +EXPORT_SYMBOL_GPL(pci_generic_config_write32); + +/** + * pci_bus_set_ops - Set raw operations of pci bus + * @bus: pci bus struct + * @ops: new raw operations + * + * Return previous raw operations + */ +struct pci_ops *pci_bus_set_ops(struct pci_bus *bus, struct pci_ops *ops) +{ + struct pci_ops *old_ops; + unsigned long flags; + + raw_spin_lock_irqsave(&pci_lock, flags); + old_ops = bus->ops; + bus->ops = ops; + raw_spin_unlock_irqrestore(&pci_lock, flags); + return old_ops; +} +EXPORT_SYMBOL(pci_bus_set_ops); + +/* + * 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_cfg_wait); + +static noinline void pci_wait_cfg(struct pci_dev *dev) + __must_hold(&pci_lock) +{ + do { + raw_spin_unlock_irq(&pci_lock); + wait_event(pci_cfg_wait, !dev->block_cfg_access); + raw_spin_lock_irq(&pci_lock); + } while (dev->block_cfg_access); +} + +/* Returns 0 on success, negative values indicate error. */ +#define PCI_USER_READ_CONFIG(size, type) \ +int pci_user_read_config_##size \ + (struct pci_dev *dev, int pos, type *val) \ +{ \ + int ret = PCIBIOS_SUCCESSFUL; \ + u32 data = -1; \ + if (PCI_##size##_BAD) \ + return -EINVAL; \ + raw_spin_lock_irq(&pci_lock); \ + if (unlikely(dev->block_cfg_access)) \ + pci_wait_cfg(dev); \ + ret = dev->bus->ops->read(dev->bus, dev->devfn, \ + pos, sizeof(type), &data); \ + raw_spin_unlock_irq(&pci_lock); \ + *val = (type)data; \ + return pcibios_err_to_errno(ret); \ +} \ +EXPORT_SYMBOL_GPL(pci_user_read_config_##size); + +/* Returns 0 on success, negative values indicate error. */ +#define PCI_USER_WRITE_CONFIG(size, type) \ +int pci_user_write_config_##size \ + (struct pci_dev *dev, int pos, type val) \ +{ \ + int ret = PCIBIOS_SUCCESSFUL; \ + if (PCI_##size##_BAD) \ + return -EINVAL; \ + raw_spin_lock_irq(&pci_lock); \ + if (unlikely(dev->block_cfg_access)) \ + pci_wait_cfg(dev); \ + ret = dev->bus->ops->write(dev->bus, dev->devfn, \ + pos, sizeof(type), val); \ + raw_spin_unlock_irq(&pci_lock); \ + return pcibios_err_to_errno(ret); \ +} \ +EXPORT_SYMBOL_GPL(pci_user_write_config_##size); + +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) + +/** + * pci_cfg_access_lock - Lock PCI config reads/writes + * @dev: pci device struct + * + * When access is locked, any userspace reads or writes to config + * space and concurrent lock requests will sleep until access is + * allowed via pci_cfg_access_unlock() again. + */ +void pci_cfg_access_lock(struct pci_dev *dev) +{ + might_sleep(); + + raw_spin_lock_irq(&pci_lock); + if (dev->block_cfg_access) + pci_wait_cfg(dev); + dev->block_cfg_access = 1; + raw_spin_unlock_irq(&pci_lock); +} +EXPORT_SYMBOL_GPL(pci_cfg_access_lock); + +/** + * pci_cfg_access_trylock - try to lock PCI config reads/writes + * @dev: pci device struct + * + * Same as pci_cfg_access_lock, but will return 0 if access is + * already locked, 1 otherwise. This function can be used from + * atomic contexts. + */ +bool pci_cfg_access_trylock(struct pci_dev *dev) +{ + unsigned long flags; + bool locked = true; + + raw_spin_lock_irqsave(&pci_lock, flags); + if (dev->block_cfg_access) + locked = false; + else + dev->block_cfg_access = 1; + raw_spin_unlock_irqrestore(&pci_lock, flags); + + return locked; +} +EXPORT_SYMBOL_GPL(pci_cfg_access_trylock); + +/** + * pci_cfg_access_unlock - Unlock PCI config reads/writes + * @dev: pci device struct + * + * This function allows PCI config accesses to resume. + */ +void pci_cfg_access_unlock(struct pci_dev *dev) +{ + unsigned long flags; + + raw_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_cfg_access); + + dev->block_cfg_access = 0; + raw_spin_unlock_irqrestore(&pci_lock, flags); + + wake_up_all(&pci_cfg_wait); +} +EXPORT_SYMBOL_GPL(pci_cfg_access_unlock); + +static inline int pcie_cap_version(const struct pci_dev *dev) +{ + return pcie_caps_reg(dev) & PCI_EXP_FLAGS_VERS; +} + +static bool pcie_downstream_port(const struct pci_dev *dev) +{ + int type = pci_pcie_type(dev); + + return type == PCI_EXP_TYPE_ROOT_PORT || + type == PCI_EXP_TYPE_DOWNSTREAM || + type == PCI_EXP_TYPE_PCIE_BRIDGE; +} + +bool pcie_cap_has_lnkctl(const struct pci_dev *dev) +{ + int type = pci_pcie_type(dev); + + return type == PCI_EXP_TYPE_ENDPOINT || + type == PCI_EXP_TYPE_LEG_END || + type == PCI_EXP_TYPE_ROOT_PORT || + type == PCI_EXP_TYPE_UPSTREAM || + type == PCI_EXP_TYPE_DOWNSTREAM || + type == PCI_EXP_TYPE_PCI_BRIDGE || + type == PCI_EXP_TYPE_PCIE_BRIDGE; +} + +static inline bool pcie_cap_has_sltctl(const struct pci_dev *dev) +{ + return pcie_downstream_port(dev) && + pcie_caps_reg(dev) & PCI_EXP_FLAGS_SLOT; +} + +static inline bool pcie_cap_has_rtctl(const struct pci_dev *dev) +{ + int type = pci_pcie_type(dev); + + return type == PCI_EXP_TYPE_ROOT_PORT || + type == PCI_EXP_TYPE_RC_EC; +} + +static bool pcie_capability_reg_implemented(struct pci_dev *dev, int pos) +{ + if (!pci_is_pcie(dev)) + return false; + + switch (pos) { + case PCI_EXP_FLAGS: + return true; + case PCI_EXP_DEVCAP: + case PCI_EXP_DEVCTL: + case PCI_EXP_DEVSTA: + return true; + case PCI_EXP_LNKCAP: + case PCI_EXP_LNKCTL: + case PCI_EXP_LNKSTA: + return pcie_cap_has_lnkctl(dev); + case PCI_EXP_SLTCAP: + case PCI_EXP_SLTCTL: + case PCI_EXP_SLTSTA: + return pcie_cap_has_sltctl(dev); + case PCI_EXP_RTCTL: + case PCI_EXP_RTCAP: + case PCI_EXP_RTSTA: + return pcie_cap_has_rtctl(dev); + case PCI_EXP_DEVCAP2: + case PCI_EXP_DEVCTL2: + case PCI_EXP_LNKCAP2: + case PCI_EXP_LNKCTL2: + case PCI_EXP_LNKSTA2: + return pcie_cap_version(dev) > 1; + default: + return false; + } +} + +/* + * Note that these accessor functions are only for the "PCI Express + * Capability" (see PCIe spec r3.0, sec 7.8). They do not apply to the + * other "PCI Express Extended Capabilities" (AER, VC, ACS, MFVC, etc.) + */ +int pcie_capability_read_word(struct pci_dev *dev, int pos, u16 *val) +{ + int ret; + + *val = 0; + if (pos & 1) + return -EINVAL; + + if (pcie_capability_reg_implemented(dev, pos)) { + ret = pci_read_config_word(dev, pci_pcie_cap(dev) + pos, val); + /* + * Reset *val to 0 if pci_read_config_word() fails, it may + * have been written as 0xFFFF if hardware error happens + * during pci_read_config_word(). + */ + if (ret) + *val = 0; + return ret; + } + + /* + * For Functions that do not implement the Slot Capabilities, + * Slot Status, and Slot Control registers, these spaces must + * be hardwired to 0b, with the exception of the Presence Detect + * State bit in the Slot Status register of Downstream Ports, + * which must be hardwired to 1b. (PCIe Base Spec 3.0, sec 7.8) + */ + if (pci_is_pcie(dev) && pcie_downstream_port(dev) && + pos == PCI_EXP_SLTSTA) + *val = PCI_EXP_SLTSTA_PDS; + + return 0; +} +EXPORT_SYMBOL(pcie_capability_read_word); + +int pcie_capability_read_dword(struct pci_dev *dev, int pos, u32 *val) +{ + int ret; + + *val = 0; + if (pos & 3) + return -EINVAL; + + if (pcie_capability_reg_implemented(dev, pos)) { + ret = pci_read_config_dword(dev, pci_pcie_cap(dev) + pos, val); + /* + * Reset *val to 0 if pci_read_config_dword() fails, it may + * have been written as 0xFFFFFFFF if hardware error happens + * during pci_read_config_dword(). + */ + if (ret) + *val = 0; + return ret; + } + + if (pci_is_pcie(dev) && pcie_downstream_port(dev) && + pos == PCI_EXP_SLTSTA) + *val = PCI_EXP_SLTSTA_PDS; + + return 0; +} +EXPORT_SYMBOL(pcie_capability_read_dword); + +int pcie_capability_write_word(struct pci_dev *dev, int pos, u16 val) +{ + if (pos & 1) + return -EINVAL; + + if (!pcie_capability_reg_implemented(dev, pos)) + return 0; + + return pci_write_config_word(dev, pci_pcie_cap(dev) + pos, val); +} +EXPORT_SYMBOL(pcie_capability_write_word); + +int pcie_capability_write_dword(struct pci_dev *dev, int pos, u32 val) +{ + if (pos & 3) + return -EINVAL; + + if (!pcie_capability_reg_implemented(dev, pos)) + return 0; + + return pci_write_config_dword(dev, pci_pcie_cap(dev) + pos, val); +} +EXPORT_SYMBOL(pcie_capability_write_dword); + +int pcie_capability_clear_and_set_word(struct pci_dev *dev, int pos, + u16 clear, u16 set) +{ + int ret; + u16 val; + + ret = pcie_capability_read_word(dev, pos, &val); + if (!ret) { + val &= ~clear; + val |= set; + ret = pcie_capability_write_word(dev, pos, val); + } + + return ret; +} +EXPORT_SYMBOL(pcie_capability_clear_and_set_word); + +int pcie_capability_clear_and_set_dword(struct pci_dev *dev, int pos, + u32 clear, u32 set) +{ + int ret; + u32 val; + + ret = pcie_capability_read_dword(dev, pos, &val); + if (!ret) { + val &= ~clear; + val |= set; + ret = pcie_capability_write_dword(dev, pos, val); + } + + return ret; +} +EXPORT_SYMBOL(pcie_capability_clear_and_set_dword); + +int pci_read_config_byte(const struct pci_dev *dev, int where, u8 *val) +{ + if (pci_dev_is_disconnected(dev)) { + *val = ~0; + return PCIBIOS_DEVICE_NOT_FOUND; + } + return pci_bus_read_config_byte(dev->bus, dev->devfn, where, val); +} +EXPORT_SYMBOL(pci_read_config_byte); + +int pci_read_config_word(const struct pci_dev *dev, int where, u16 *val) +{ + if (pci_dev_is_disconnected(dev)) { + *val = ~0; + return PCIBIOS_DEVICE_NOT_FOUND; + } + return pci_bus_read_config_word(dev->bus, dev->devfn, where, val); +} +EXPORT_SYMBOL(pci_read_config_word); + +int pci_read_config_dword(const struct pci_dev *dev, int where, + u32 *val) +{ + if (pci_dev_is_disconnected(dev)) { + *val = ~0; + return PCIBIOS_DEVICE_NOT_FOUND; + } + return pci_bus_read_config_dword(dev->bus, dev->devfn, where, val); +} +EXPORT_SYMBOL(pci_read_config_dword); + +int pci_write_config_byte(const struct pci_dev *dev, int where, u8 val) +{ + if (pci_dev_is_disconnected(dev)) + return PCIBIOS_DEVICE_NOT_FOUND; + return pci_bus_write_config_byte(dev->bus, dev->devfn, where, val); +} +EXPORT_SYMBOL(pci_write_config_byte); + +int pci_write_config_word(const struct pci_dev *dev, int where, u16 val) +{ + if (pci_dev_is_disconnected(dev)) + return PCIBIOS_DEVICE_NOT_FOUND; + return pci_bus_write_config_word(dev->bus, dev->devfn, where, val); +} +EXPORT_SYMBOL(pci_write_config_word); + +int pci_write_config_dword(const struct pci_dev *dev, int where, + u32 val) +{ + if (pci_dev_is_disconnected(dev)) + return PCIBIOS_DEVICE_NOT_FOUND; + return pci_bus_write_config_dword(dev->bus, dev->devfn, where, val); +} +EXPORT_SYMBOL(pci_write_config_dword); |