#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/pm_runtime.h>
+ #include <linux/pci_hotplug.h>
#include <asm-generic/pci-bridge.h>
#include <asm/setup.h>
#include "pci.h"
}
/**
- * pci_add_save_buffer - allocate buffer for saving given capability registers
+ * pci_add_cap_save_buffer - allocate buffer for saving given capability registers
* @dev: the PCI device
* @cap: the capability to allocate the buffer for
* @size: requested size of the buffer
pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl);
}
+static bool pci_acs_flags_enabled(struct pci_dev *pdev, u16 acs_flags)
+{
+ int pos;
+ u16 cap, ctrl;
+
+ pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ACS);
+ if (!pos)
+ return false;
+
+ /*
+ * Except for egress control, capabilities are either required
+ * or only required if controllable. Features missing from the
+ * capability field can therefore be assumed as hard-wired enabled.
+ */
+ pci_read_config_word(pdev, pos + PCI_ACS_CAP, &cap);
+ acs_flags &= (cap | PCI_ACS_EC);
+
+ pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl);
+ return (ctrl & acs_flags) == acs_flags;
+}
+
/**
* pci_acs_enabled - test ACS against required flags for a given device
* @pdev: device to test
*
* Return true if the device supports the provided flags. Automatically
* filters out flags that are not implemented on multifunction devices.
+ *
+ * Note that this interface checks the effective ACS capabilities of the
+ * device rather than the actual capabilities. For instance, most single
+ * function endpoints are not required to support ACS because they have no
+ * opportunity for peer-to-peer access. We therefore return 'true'
+ * regardless of whether the device exposes an ACS capability. This makes
+ * it much easier for callers of this function to ignore the actual type
+ * or topology of the device when testing ACS support.
*/
bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags)
{
- int pos, ret;
- u16 ctrl;
+ int ret;
ret = pci_dev_specific_acs_enabled(pdev, acs_flags);
if (ret >= 0)
return ret > 0;
+ /*
+ * Conventional PCI and PCI-X devices never support ACS, either
+ * effectively or actually. The shared bus topology implies that
+ * any device on the bus can receive or snoop DMA.
+ */
if (!pci_is_pcie(pdev))
return false;
- /* Filter out flags not applicable to multifunction */
- if (pdev->multifunction)
- acs_flags &= (PCI_ACS_RR | PCI_ACS_CR |
- PCI_ACS_EC | PCI_ACS_DT);
-
- if (pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM ||
- pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
- pdev->multifunction) {
- pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ACS);
- if (!pos)
- return false;
+ switch (pci_pcie_type(pdev)) {
+ /*
+ * PCI/X-to-PCIe bridges are not specifically mentioned by the spec,
+ * but since their primary inteface is PCI/X, we conservatively
+ * handle them as we would a non-PCIe device.
+ */
+ case PCI_EXP_TYPE_PCIE_BRIDGE:
+ /*
+ * PCIe 3.0, 6.12.1 excludes ACS on these devices. "ACS is never
+ * applicable... must never implement an ACS Extended Capability...".
+ * This seems arbitrary, but we take a conservative interpretation
+ * of this statement.
+ */
+ case PCI_EXP_TYPE_PCI_BRIDGE:
+ case PCI_EXP_TYPE_RC_EC:
+ return false;
+ /*
+ * PCIe 3.0, 6.12.1.1 specifies that downstream and root ports should
+ * implement ACS in order to indicate their peer-to-peer capabilities,
+ * regardless of whether they are single- or multi-function devices.
+ */
+ case PCI_EXP_TYPE_DOWNSTREAM:
+ case PCI_EXP_TYPE_ROOT_PORT:
+ return pci_acs_flags_enabled(pdev, acs_flags);
+ /*
+ * PCIe 3.0, 6.12.1.2 specifies ACS capabilities that should be
+ * implemented by the remaining PCIe types to indicate peer-to-peer
+ * capabilities, but only when they are part of a multifunciton
+ * device. The footnote for section 6.12 indicates the specific
+ * PCIe types included here.
+ */
+ case PCI_EXP_TYPE_ENDPOINT:
+ case PCI_EXP_TYPE_UPSTREAM:
+ case PCI_EXP_TYPE_LEG_END:
+ case PCI_EXP_TYPE_RC_END:
+ if (!pdev->multifunction)
+ break;
- pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl);
- if ((ctrl & acs_flags) != acs_flags)
- return false;
+ return pci_acs_flags_enabled(pdev, acs_flags);
}
+ /*
+ * PCIe 3.0, 6.12.1.3 specifies no ACS capabilties are applicable
+ * to single function devices with the exception of downstream ports.
+ */
return true;
}
}
EXPORT_SYMBOL(pci_set_dma_seg_boundary);
-static int pcie_flr(struct pci_dev *dev, int probe)
+/**
+ * pci_wait_for_pending_transaction - waits for pending transaction
+ * @dev: the PCI device to operate on
+ *
+ * Return 0 if transaction is pending 1 otherwise.
+ */
+int pci_wait_for_pending_transaction(struct pci_dev *dev)
{
int i;
- u32 cap;
u16 status;
- pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
- if (!(cap & PCI_EXP_DEVCAP_FLR))
- return -ENOTTY;
-
- if (probe)
- return 0;
-
/* Wait for Transaction Pending bit clean */
for (i = 0; i < 4; i++) {
if (i)
pcie_capability_read_word(dev, PCI_EXP_DEVSTA, &status);
if (!(status & PCI_EXP_DEVSTA_TRPND))
- goto clear;
+ return 1;
}
- dev_err(&dev->dev, "transaction is not cleared; "
- "proceeding with reset anyway\n");
+ return 0;
+}
+EXPORT_SYMBOL(pci_wait_for_pending_transaction);
+
+static int pcie_flr(struct pci_dev *dev, int probe)
+{
+ u32 cap;
+
+ pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
+ if (!(cap & PCI_EXP_DEVCAP_FLR))
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ if (!pci_wait_for_pending_transaction(dev))
+ dev_err(&dev->dev, "transaction is not cleared; proceeding with reset anyway\n");
-clear:
pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_BCR_FLR);
msleep(100);
return 0;
}
- static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
+ /**
+ * pci_reset_bridge_secondary_bus - Reset the secondary bus on a PCI bridge.
+ * @dev: Bridge device
+ *
+ * Use the bridge control register to assert reset on the secondary bus.
+ * Devices on the secondary bus are left in power-on state.
+ */
+ void pci_reset_bridge_secondary_bus(struct pci_dev *dev)
{
u16 ctrl;
+
+ pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &ctrl);
+ ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
+ pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
+ /*
+ * PCI spec v3.0 7.6.4.2 requires minimum Trst of 1ms. Double
+ * this to 2ms to ensure that we meet the minium requirement.
+ */
+ msleep(2);
+
+ ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
+ pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
+
+ /*
+ * Trhfa for conventional PCI is 2^25 clock cycles.
+ * Assuming a minimum 33MHz clock this results in a 1s
+ * delay before we can consider subordinate devices to
+ * be re-initialized. PCIe has some ways to shorten this,
+ * but we don't make use of them yet.
+ */
+ ssleep(1);
+ }
+ EXPORT_SYMBOL_GPL(pci_reset_bridge_secondary_bus);
+
+ static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
+ {
struct pci_dev *pdev;
if (pci_is_root_bus(dev->bus) || dev->subordinate || !dev->bus->self)
if (probe)
return 0;
- pci_read_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, &ctrl);
- ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
- pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
- msleep(100);
-
- ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
- pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
- msleep(100);
+ pci_reset_bridge_secondary_bus(dev->bus->self);
return 0;
}
+ static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, int probe)
+ {
+ int rc = -ENOTTY;
+
+ if (!hotplug || !try_module_get(hotplug->ops->owner))
+ return rc;
+
+ if (hotplug->ops->reset_slot)
+ rc = hotplug->ops->reset_slot(hotplug, probe);
+
+ module_put(hotplug->ops->owner);
+
+ return rc;
+ }
+
+ static int pci_dev_reset_slot_function(struct pci_dev *dev, int probe)
+ {
+ struct pci_dev *pdev;
+
+ if (dev->subordinate || !dev->slot)
+ return -ENOTTY;
+
+ list_for_each_entry(pdev, &dev->bus->devices, bus_list)
+ if (pdev != dev && pdev->slot == dev->slot)
+ return -ENOTTY;
+
+ return pci_reset_hotplug_slot(dev->slot->hotplug, probe);
+ }
+
static int __pci_dev_reset(struct pci_dev *dev, int probe)
{
int rc;
if (rc != -ENOTTY)
goto done;
+ rc = pci_dev_reset_slot_function(dev, probe);
+ if (rc != -ENOTTY)
+ goto done;
+
rc = pci_parent_bus_reset(dev, probe);
done:
return rc;
}
+ static void pci_dev_lock(struct pci_dev *dev)
+ {
+ pci_cfg_access_lock(dev);
+ /* block PM suspend, driver probe, etc. */
+ device_lock(&dev->dev);
+ }
+
+ static void pci_dev_unlock(struct pci_dev *dev)
+ {
+ device_unlock(&dev->dev);
+ pci_cfg_access_unlock(dev);
+ }
+
+ static void pci_dev_save_and_disable(struct pci_dev *dev)
+ {
+ /*
+ * Wake-up device prior to save. PM registers default to D0 after
+ * reset and a simple register restore doesn't reliably return
+ * to a non-D0 state anyway.
+ */
+ pci_set_power_state(dev, PCI_D0);
+
+ pci_save_state(dev);
+ /*
+ * Disable the device by clearing the Command register, except for
+ * INTx-disable which is set. This not only disables MMIO and I/O port
+ * BARs, but also prevents the device from being Bus Master, preventing
+ * DMA from the device including MSI/MSI-X interrupts. For PCI 2.3
+ * compliant devices, INTx-disable prevents legacy interrupts.
+ */
+ pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
+ }
+
+ static void pci_dev_restore(struct pci_dev *dev)
+ {
+ pci_restore_state(dev);
+ }
+
static int pci_dev_reset(struct pci_dev *dev, int probe)
{
int rc;
- if (!probe) {
- pci_cfg_access_lock(dev);
- /* block PM suspend, driver probe, etc. */
- device_lock(&dev->dev);
- }
+ if (!probe)
+ pci_dev_lock(dev);
rc = __pci_dev_reset(dev, probe);
- if (!probe) {
- device_unlock(&dev->dev);
- pci_cfg_access_unlock(dev);
- }
+ if (!probe)
+ pci_dev_unlock(dev);
+
return rc;
}
/**
if (rc)
return rc;
- pci_save_state(dev);
-
- /*
- * both INTx and MSI are disabled after the Interrupt Disable bit
- * is set and the Bus Master bit is cleared.
- */
- pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
+ pci_dev_save_and_disable(dev);
rc = pci_dev_reset(dev, 0);
- pci_restore_state(dev);
+ pci_dev_restore(dev);
return rc;
}
EXPORT_SYMBOL_GPL(pci_reset_function);
+ /* Lock devices from the top of the tree down */
+ static void pci_bus_lock(struct pci_bus *bus)
+ {
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ pci_dev_lock(dev);
+ if (dev->subordinate)
+ pci_bus_lock(dev->subordinate);
+ }
+ }
+
+ /* Unlock devices from the bottom of the tree up */
+ static void pci_bus_unlock(struct pci_bus *bus)
+ {
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ if (dev->subordinate)
+ pci_bus_unlock(dev->subordinate);
+ pci_dev_unlock(dev);
+ }
+ }
+
+ /* Lock devices from the top of the tree down */
+ static void pci_slot_lock(struct pci_slot *slot)
+ {
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &slot->bus->devices, bus_list) {
+ if (!dev->slot || dev->slot != slot)
+ continue;
+ pci_dev_lock(dev);
+ if (dev->subordinate)
+ pci_bus_lock(dev->subordinate);
+ }
+ }
+
+ /* Unlock devices from the bottom of the tree up */
+ static void pci_slot_unlock(struct pci_slot *slot)
+ {
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &slot->bus->devices, bus_list) {
+ if (!dev->slot || dev->slot != slot)
+ continue;
+ if (dev->subordinate)
+ pci_bus_unlock(dev->subordinate);
+ pci_dev_unlock(dev);
+ }
+ }
+
+ /* Save and disable devices from the top of the tree down */
+ static void pci_bus_save_and_disable(struct pci_bus *bus)
+ {
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ pci_dev_save_and_disable(dev);
+ if (dev->subordinate)
+ pci_bus_save_and_disable(dev->subordinate);
+ }
+ }
+
+ /*
+ * Restore devices from top of the tree down - parent bridges need to be
+ * restored before we can get to subordinate devices.
+ */
+ static void pci_bus_restore(struct pci_bus *bus)
+ {
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ pci_dev_restore(dev);
+ if (dev->subordinate)
+ pci_bus_restore(dev->subordinate);
+ }
+ }
+
+ /* Save and disable devices from the top of the tree down */
+ static void pci_slot_save_and_disable(struct pci_slot *slot)
+ {
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &slot->bus->devices, bus_list) {
+ if (!dev->slot || dev->slot != slot)
+ continue;
+ pci_dev_save_and_disable(dev);
+ if (dev->subordinate)
+ pci_bus_save_and_disable(dev->subordinate);
+ }
+ }
+
+ /*
+ * Restore devices from top of the tree down - parent bridges need to be
+ * restored before we can get to subordinate devices.
+ */
+ static void pci_slot_restore(struct pci_slot *slot)
+ {
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &slot->bus->devices, bus_list) {
+ if (!dev->slot || dev->slot != slot)
+ continue;
+ pci_dev_restore(dev);
+ if (dev->subordinate)
+ pci_bus_restore(dev->subordinate);
+ }
+ }
+
+ static int pci_slot_reset(struct pci_slot *slot, int probe)
+ {
+ int rc;
+
+ if (!slot)
+ return -ENOTTY;
+
+ if (!probe)
+ pci_slot_lock(slot);
+
+ might_sleep();
+
+ rc = pci_reset_hotplug_slot(slot->hotplug, probe);
+
+ if (!probe)
+ pci_slot_unlock(slot);
+
+ return rc;
+ }
+
+ /**
+ * pci_probe_reset_slot - probe whether a PCI slot can be reset
+ * @slot: PCI slot to probe
+ *
+ * Return 0 if slot can be reset, negative if a slot reset is not supported.
+ */
+ int pci_probe_reset_slot(struct pci_slot *slot)
+ {
+ return pci_slot_reset(slot, 1);
+ }
+ EXPORT_SYMBOL_GPL(pci_probe_reset_slot);
+
+ /**
+ * pci_reset_slot - reset a PCI slot
+ * @slot: PCI slot to reset
+ *
+ * A PCI bus may host multiple slots, each slot may support a reset mechanism
+ * independent of other slots. For instance, some slots may support slot power
+ * control. In the case of a 1:1 bus to slot architecture, this function may
+ * wrap the bus reset to avoid spurious slot related events such as hotplug.
+ * Generally a slot reset should be attempted before a bus reset. All of the
+ * function of the slot and any subordinate buses behind the slot are reset
+ * through this function. PCI config space of all devices in the slot and
+ * behind the slot is saved before and restored after reset.
+ *
+ * Return 0 on success, non-zero on error.
+ */
+ int pci_reset_slot(struct pci_slot *slot)
+ {
+ int rc;
+
+ rc = pci_slot_reset(slot, 1);
+ if (rc)
+ return rc;
+
+ pci_slot_save_and_disable(slot);
+
+ rc = pci_slot_reset(slot, 0);
+
+ pci_slot_restore(slot);
+
+ return rc;
+ }
+ EXPORT_SYMBOL_GPL(pci_reset_slot);
+
+ static int pci_bus_reset(struct pci_bus *bus, int probe)
+ {
+ if (!bus->self)
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ pci_bus_lock(bus);
+
+ might_sleep();
+
+ pci_reset_bridge_secondary_bus(bus->self);
+
+ pci_bus_unlock(bus);
+
+ return 0;
+ }
+
+ /**
+ * pci_probe_reset_bus - probe whether a PCI bus can be reset
+ * @bus: PCI bus to probe
+ *
+ * Return 0 if bus can be reset, negative if a bus reset is not supported.
+ */
+ int pci_probe_reset_bus(struct pci_bus *bus)
+ {
+ return pci_bus_reset(bus, 1);
+ }
+ EXPORT_SYMBOL_GPL(pci_probe_reset_bus);
+
+ /**
+ * pci_reset_bus - reset a PCI bus
+ * @bus: top level PCI bus to reset
+ *
+ * Do a bus reset on the given bus and any subordinate buses, saving
+ * and restoring state of all devices.
+ *
+ * Return 0 on success, non-zero on error.
+ */
+ int pci_reset_bus(struct pci_bus *bus)
+ {
+ int rc;
+
+ rc = pci_bus_reset(bus, 1);
+ if (rc)
+ return rc;
+
+ pci_bus_save_and_disable(bus);
+
+ rc = pci_bus_reset(bus, 0);
+
+ pci_bus_restore(bus);
+
+ return rc;
+ }
+ EXPORT_SYMBOL_GPL(pci_reset_bus);
+
/**
* pcix_get_max_mmrbc - get PCI-X maximum designed memory read byte count
* @dev: PCI device to query
projects / linux.git / commitdiff