summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/pci/access.c
diff options
context:
space:
mode:
authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/pci/access.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/pci/access.c')
-rw-r--r--kernel/drivers/pci/access.c725
1 files changed, 725 insertions, 0 deletions
diff --git a/kernel/drivers/pci/access.c b/kernel/drivers/pci/access.c
new file mode 100644
index 000000000..1d0f6f8d0
--- /dev/null
+++ b/kernel/drivers/pci/access.c
@@ -0,0 +1,725 @@
+#include <linux/delay.h>
+#include <linux/pci.h>
+#include <linux/module.h>
+#include <linux/sched.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)
+
+#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; \
+ raw_spin_lock_irqsave(&pci_lock, flags); \
+ res = bus->ops->read(bus, devfn, pos, len, &data); \
+ *value = (type)data; \
+ raw_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; \
+ raw_spin_lock_irqsave(&pci_lock, flags); \
+ res = bus->ops->write(bus, devfn, pos, len, value); \
+ raw_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);
+
+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;
+ } else {
+ 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);
+
+/**
+ * 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_cfg_wait);
+
+static noinline void pci_wait_cfg(struct pci_dev *dev)
+{
+ DECLARE_WAITQUEUE(wait, current);
+
+ __add_wait_queue(&pci_cfg_wait, &wait);
+ do {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ raw_spin_unlock_irq(&pci_lock);
+ schedule();
+ raw_spin_lock_irq(&pci_lock);
+ } while (dev->block_cfg_access);
+ __remove_wait_queue(&pci_cfg_wait, &wait);
+}
+
+/* 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)
+
+/* 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.
+ *
+ * Returns 0 on success, negative values indicate error.
+ */
+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 < 0)
+ return ret;
+
+ if ((status & PCI_VPD_ADDR_F) == vpd->flag) {
+ vpd->busy = false;
+ return 0;
+ }
+
+ if (time_after(jiffies, timeout)) {
+ dev_printk(KERN_DEBUG, &dev->dev, "vpd r/w failed. This is likely a firmware bug on this device. Contact the card vendor for a firmware update\n");
+ 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);
+ if (ret < 0)
+ break;
+
+ 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_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_unlocked 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;
+ wake_up_all_locked(&pci_cfg_wait);
+ raw_spin_unlock_irqrestore(&pci_lock, flags);
+}
+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;
+}
+
+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)
+{
+ int type = pci_pcie_type(dev);
+
+ return (type == PCI_EXP_TYPE_ROOT_PORT ||
+ type == PCI_EXP_TYPE_DOWNSTREAM) &&
+ 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) && pos == PCI_EXP_SLTSTA &&
+ pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM) {
+ *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) && pos == PCI_EXP_SLTCTL &&
+ pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM) {
+ *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);