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Message-Id: <20250512120900.1870-1-ilpo.jarvinen@linux.intel.com>
Date: Mon, 12 May 2025 15:08:57 +0300
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>,
linux-kernel@...r.kernel.org,
linux-pci@...r.kernel.org
Cc: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: [PATCH 1/1] PCI: Move reset and restore related code to reset-restore.c
There are quite many reset and restore related functions in pci.c that
barely depend on the other functions in pci.c. Create reset-restore.c
for reset and restore related logic to keep those 1k lines in one place.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
---
Based on top of the pci/reset branch. AFAIK, there shouldn't be major
conflicts because of this with what's currently among the accepted
changes.
drivers/pci/Makefile | 4 +-
drivers/pci/pci.c | 1015 +----------------------------------
drivers/pci/pci.h | 10 +
drivers/pci/reset-restore.c | 1014 ++++++++++++++++++++++++++++++++++
4 files changed, 1028 insertions(+), 1015 deletions(-)
create mode 100644 drivers/pci/reset-restore.c
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 67647f1880fb..28f4748a63e9 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -3,8 +3,8 @@
# Makefile for the PCI bus specific drivers.
obj-$(CONFIG_PCI) += access.o bus.o probe.o host-bridge.o \
- remove.o pci.o pci-driver.o search.o \
- rom.o setup-res.o irq.o vpd.o \
+ remove.o reset-restore.o pci.o pci-driver.o \
+ search.o rom.o setup-res.o irq.o vpd.o \
setup-bus.o vc.o mmap.o devres.o
obj-$(CONFIG_PCI) += msi/
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 26507aa906d7..076b690191ea 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -69,15 +69,7 @@ struct pci_pme_device {
*/
#define PCI_RESET_WAIT 1000 /* msec */
-/*
- * Devices may extend the 1 sec period through Request Retry Status
- * completions (PCIe r6.0 sec 2.3.1). The spec does not provide an upper
- * limit, but 60 sec ought to be enough for any device to become
- * responsive.
- */
-#define PCIE_RESET_READY_POLL_MS 60000 /* msec */
-
-static void pci_dev_d3_sleep(struct pci_dev *dev)
+void pci_dev_d3_sleep(struct pci_dev *dev)
{
unsigned int delay_ms = max(dev->d3hot_delay, pci_pm_d3hot_delay);
unsigned int upper;
@@ -90,11 +82,6 @@ static void pci_dev_d3_sleep(struct pci_dev *dev)
}
}
-bool pci_reset_supported(struct pci_dev *dev)
-{
- return dev->reset_methods[0] != 0;
-}
-
#ifdef CONFIG_PCI_DOMAINS
int pci_domains_supported = 1;
#endif
@@ -1262,7 +1249,7 @@ void pci_resume_bus(struct pci_bus *bus)
pci_walk_bus(bus, pci_resume_one, NULL);
}
-static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
+int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
{
int delay = 1;
bool retrain = false;
@@ -2293,33 +2280,6 @@ void pci_disable_device(struct pci_dev *dev)
}
EXPORT_SYMBOL(pci_disable_device);
-/**
- * pcibios_set_pcie_reset_state - set reset state for device dev
- * @dev: the PCIe device reset
- * @state: Reset state to enter into
- *
- * Set the PCIe reset state for the device. This is the default
- * implementation. Architecture implementations can override this.
- */
-int __weak pcibios_set_pcie_reset_state(struct pci_dev *dev,
- enum pcie_reset_state state)
-{
- return -EINVAL;
-}
-
-/**
- * pci_set_pcie_reset_state - set reset state for device dev
- * @dev: the PCIe device reset
- * @state: Reset state to enter into
- *
- * Sets the PCI reset state for the device.
- */
-int pci_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
-{
- return pcibios_set_pcie_reset_state(dev, state);
-}
-EXPORT_SYMBOL_GPL(pci_set_pcie_reset_state);
-
#ifdef CONFIG_PCIEAER
void pcie_clear_device_status(struct pci_dev *dev)
{
@@ -4544,145 +4504,6 @@ int pci_wait_for_pending_transaction(struct pci_dev *dev)
}
EXPORT_SYMBOL(pci_wait_for_pending_transaction);
-/**
- * pcie_flr - initiate a PCIe function level reset
- * @dev: device to reset
- *
- * Initiate a function level reset unconditionally on @dev without
- * checking any flags and DEVCAP
- */
-int pcie_flr(struct pci_dev *dev)
-{
- if (!pci_wait_for_pending_transaction(dev))
- pci_err(dev, "timed out waiting for pending transaction; performing function level reset anyway\n");
-
- pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_BCR_FLR);
-
- if (dev->imm_ready)
- return 0;
-
- /*
- * Per PCIe r4.0, sec 6.6.2, a device must complete an FLR within
- * 100ms, but may silently discard requests while the FLR is in
- * progress. Wait 100ms before trying to access the device.
- */
- msleep(100);
-
- return pci_dev_wait(dev, "FLR", PCIE_RESET_READY_POLL_MS);
-}
-EXPORT_SYMBOL_GPL(pcie_flr);
-
-/**
- * pcie_reset_flr - initiate a PCIe function level reset
- * @dev: device to reset
- * @probe: if true, return 0 if device can be reset this way
- *
- * Initiate a function level reset on @dev.
- */
-int pcie_reset_flr(struct pci_dev *dev, bool probe)
-{
- if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
- return -ENOTTY;
-
- if (!(dev->devcap & PCI_EXP_DEVCAP_FLR))
- return -ENOTTY;
-
- if (probe)
- return 0;
-
- return pcie_flr(dev);
-}
-EXPORT_SYMBOL_GPL(pcie_reset_flr);
-
-static int pci_af_flr(struct pci_dev *dev, bool probe)
-{
- int pos;
- u8 cap;
-
- pos = pci_find_capability(dev, PCI_CAP_ID_AF);
- if (!pos)
- return -ENOTTY;
-
- if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
- return -ENOTTY;
-
- pci_read_config_byte(dev, pos + PCI_AF_CAP, &cap);
- if (!(cap & PCI_AF_CAP_TP) || !(cap & PCI_AF_CAP_FLR))
- return -ENOTTY;
-
- if (probe)
- return 0;
-
- /*
- * Wait for Transaction Pending bit to clear. A word-aligned test
- * is used, so we use the control offset rather than status and shift
- * the test bit to match.
- */
- if (!pci_wait_for_pending(dev, pos + PCI_AF_CTRL,
- PCI_AF_STATUS_TP << 8))
- pci_err(dev, "timed out waiting for pending transaction; performing AF function level reset anyway\n");
-
- pci_write_config_byte(dev, pos + PCI_AF_CTRL, PCI_AF_CTRL_FLR);
-
- if (dev->imm_ready)
- return 0;
-
- /*
- * Per Advanced Capabilities for Conventional PCI ECN, 13 April 2006,
- * updated 27 July 2006; a device must complete an FLR within
- * 100ms, but may silently discard requests while the FLR is in
- * progress. Wait 100ms before trying to access the device.
- */
- msleep(100);
-
- return pci_dev_wait(dev, "AF_FLR", PCIE_RESET_READY_POLL_MS);
-}
-
-/**
- * pci_pm_reset - Put device into PCI_D3 and back into PCI_D0.
- * @dev: Device to reset.
- * @probe: if true, return 0 if the device can be reset this way.
- *
- * If @dev supports native PCI PM and its PCI_PM_CTRL_NO_SOFT_RESET flag is
- * unset, it will be reinitialized internally when going from PCI_D3hot to
- * PCI_D0. If that's the case and the device is not in a low-power state
- * already, force it into PCI_D3hot and back to PCI_D0, causing it to be reset.
- *
- * NOTE: This causes the caller to sleep for twice the device power transition
- * cooldown period, which for the D0->D3hot and D3hot->D0 transitions is 10 ms
- * by default (i.e. unless the @dev's d3hot_delay field has a different value).
- * Moreover, only devices in D0 can be reset by this function.
- */
-static int pci_pm_reset(struct pci_dev *dev, bool probe)
-{
- u16 csr;
-
- if (!dev->pm_cap || dev->dev_flags & PCI_DEV_FLAGS_NO_PM_RESET)
- return -ENOTTY;
-
- pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &csr);
- if (csr & PCI_PM_CTRL_NO_SOFT_RESET)
- return -ENOTTY;
-
- if (probe)
- return 0;
-
- if (dev->current_state != PCI_D0)
- return -EINVAL;
-
- csr &= ~PCI_PM_CTRL_STATE_MASK;
- csr |= PCI_D3hot;
- pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, csr);
- pci_dev_d3_sleep(dev);
-
- csr &= ~PCI_PM_CTRL_STATE_MASK;
- csr |= PCI_D0;
- pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, csr);
- pci_dev_d3_sleep(dev);
-
- return pci_dev_wait(dev, "PM D3hot->D0", PCIE_RESET_READY_POLL_MS);
-}
-
/**
* pcie_wait_for_link_status - Wait for link status change
* @pdev: Device whose link to wait for.
@@ -4962,179 +4783,6 @@ int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type)
PCIE_RESET_READY_POLL_MS - delay);
}
-void pci_reset_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 minimum requirement.
- */
- msleep(2);
-
- ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
- pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
-}
-
-void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
-{
- pci_reset_secondary_bus(dev);
-}
-
-/**
- * pci_bridge_secondary_bus_reset - 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.
- */
-int pci_bridge_secondary_bus_reset(struct pci_dev *dev)
-{
- if (!dev->block_cfg_access)
- pci_warn_once(dev, "unlocked secondary bus reset via: %pS\n",
- __builtin_return_address(0));
- pcibios_reset_secondary_bus(dev);
-
- return pci_bridge_wait_for_secondary_bus(dev, "bus reset");
-}
-EXPORT_SYMBOL_GPL(pci_bridge_secondary_bus_reset);
-
-static int pci_parent_bus_reset(struct pci_dev *dev, bool probe)
-{
- struct pci_dev *pdev;
-
- if (pci_is_root_bus(dev->bus) || dev->subordinate ||
- !dev->bus->self || dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
- return -ENOTTY;
-
- list_for_each_entry(pdev, &dev->bus->devices, bus_list)
- if (pdev != dev)
- return -ENOTTY;
-
- if (probe)
- return 0;
-
- return pci_bridge_secondary_bus_reset(dev->bus->self);
-}
-
-static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, bool probe)
-{
- int rc = -ENOTTY;
-
- if (!hotplug || !try_module_get(hotplug->owner))
- return rc;
-
- if (hotplug->ops->reset_slot)
- rc = hotplug->ops->reset_slot(hotplug, probe);
-
- module_put(hotplug->owner);
-
- return rc;
-}
-
-static int pci_dev_reset_slot_function(struct pci_dev *dev, bool probe)
-{
- if (dev->multifunction || dev->subordinate || !dev->slot ||
- dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
- return -ENOTTY;
-
- return pci_reset_hotplug_slot(dev->slot->hotplug, probe);
-}
-
-static u16 cxl_port_dvsec(struct pci_dev *dev)
-{
- return pci_find_dvsec_capability(dev, PCI_VENDOR_ID_CXL,
- PCI_DVSEC_CXL_PORT);
-}
-
-static bool cxl_sbr_masked(struct pci_dev *dev)
-{
- u16 dvsec, reg;
- int rc;
-
- dvsec = cxl_port_dvsec(dev);
- if (!dvsec)
- return false;
-
- rc = pci_read_config_word(dev, dvsec + PCI_DVSEC_CXL_PORT_CTL, ®);
- if (rc || PCI_POSSIBLE_ERROR(reg))
- return false;
-
- /*
- * Per CXL spec r3.1, sec 8.1.5.2, when "Unmask SBR" is 0, the SBR
- * bit in Bridge Control has no effect. When 1, the Port generates
- * hot reset when the SBR bit is set to 1.
- */
- if (reg & PCI_DVSEC_CXL_PORT_CTL_UNMASK_SBR)
- return false;
-
- return true;
-}
-
-static int pci_reset_bus_function(struct pci_dev *dev, bool probe)
-{
- struct pci_dev *bridge = pci_upstream_bridge(dev);
- int rc;
-
- /*
- * If "dev" is below a CXL port that has SBR control masked, SBR
- * won't do anything, so return error.
- */
- if (bridge && cxl_sbr_masked(bridge)) {
- if (probe)
- return 0;
-
- return -ENOTTY;
- }
-
- rc = pci_dev_reset_slot_function(dev, probe);
- if (rc != -ENOTTY)
- return rc;
- return pci_parent_bus_reset(dev, probe);
-}
-
-static int cxl_reset_bus_function(struct pci_dev *dev, bool probe)
-{
- struct pci_dev *bridge;
- u16 dvsec, reg, val;
- int rc;
-
- bridge = pci_upstream_bridge(dev);
- if (!bridge)
- return -ENOTTY;
-
- dvsec = cxl_port_dvsec(bridge);
- if (!dvsec)
- return -ENOTTY;
-
- if (probe)
- return 0;
-
- rc = pci_read_config_word(bridge, dvsec + PCI_DVSEC_CXL_PORT_CTL, ®);
- if (rc)
- return -ENOTTY;
-
- if (reg & PCI_DVSEC_CXL_PORT_CTL_UNMASK_SBR) {
- val = reg;
- } else {
- val = reg | PCI_DVSEC_CXL_PORT_CTL_UNMASK_SBR;
- pci_write_config_word(bridge, dvsec + PCI_DVSEC_CXL_PORT_CTL,
- val);
- }
-
- rc = pci_reset_bus_function(dev, probe);
-
- if (reg != val)
- pci_write_config_word(bridge, dvsec + PCI_DVSEC_CXL_PORT_CTL,
- reg);
-
- return rc;
-}
-
void pci_dev_lock(struct pci_dev *dev)
{
/* block PM suspend, driver probe, etc. */
@@ -5163,665 +4811,6 @@ void pci_dev_unlock(struct pci_dev *dev)
}
EXPORT_SYMBOL_GPL(pci_dev_unlock);
-static void pci_dev_save_and_disable(struct pci_dev *dev)
-{
- const struct pci_error_handlers *err_handler =
- dev->driver ? dev->driver->err_handler : NULL;
-
- /*
- * dev->driver->err_handler->reset_prepare() is protected against
- * races with ->remove() by the device lock, which must be held by
- * the caller.
- */
- if (err_handler && err_handler->reset_prepare)
- err_handler->reset_prepare(dev);
- else if (dev->driver)
- pci_warn(dev, "resetting");
-
- /*
- * 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)
-{
- const struct pci_error_handlers *err_handler =
- dev->driver ? dev->driver->err_handler : NULL;
-
- pci_restore_state(dev);
-
- /*
- * dev->driver->err_handler->reset_done() is protected against
- * races with ->remove() by the device lock, which must be held by
- * the caller.
- */
- if (err_handler && err_handler->reset_done)
- err_handler->reset_done(dev);
- else if (dev->driver)
- pci_warn(dev, "reset done");
-}
-
-/* dev->reset_methods[] is a 0-terminated list of indices into this array */
-const struct pci_reset_fn_method pci_reset_fn_methods[] = {
- { },
- { pci_dev_specific_reset, .name = "device_specific" },
- { pci_dev_acpi_reset, .name = "acpi" },
- { pcie_reset_flr, .name = "flr" },
- { pci_af_flr, .name = "af_flr" },
- { pci_pm_reset, .name = "pm" },
- { pci_reset_bus_function, .name = "bus" },
- { cxl_reset_bus_function, .name = "cxl_bus" },
-};
-
-/**
- * __pci_reset_function_locked - reset a PCI device function while holding
- * the @dev mutex lock.
- * @dev: PCI device to reset
- *
- * Some devices allow an individual function to be reset without affecting
- * other functions in the same device. The PCI device must be responsive
- * to PCI config space in order to use this function.
- *
- * The device function is presumed to be unused and the caller is holding
- * the device mutex lock when this function is called.
- *
- * Resetting the device will make the contents of PCI configuration space
- * random, so any caller of this must be prepared to reinitialise the
- * device including MSI, bus mastering, BARs, decoding IO and memory spaces,
- * etc.
- *
- * Returns 0 if the device function was successfully reset or negative if the
- * device doesn't support resetting a single function.
- */
-int __pci_reset_function_locked(struct pci_dev *dev)
-{
- int i, m, rc;
- const struct pci_reset_fn_method *method;
-
- might_sleep();
-
- /*
- * A reset method returns -ENOTTY if it doesn't support this device and
- * we should try the next method.
- *
- * If it returns 0 (success), we're finished. If it returns any other
- * error, we're also finished: this indicates that further reset
- * mechanisms might be broken on the device.
- */
- for (i = 0; i < PCI_NUM_RESET_METHODS; i++) {
- m = dev->reset_methods[i];
- if (!m)
- return -ENOTTY;
-
- method = &pci_reset_fn_methods[m];
- pci_dbg(dev, "reset via %s\n", method->name);
- rc = method->reset_fn(dev, PCI_RESET_DO_RESET);
- if (!rc)
- return 0;
-
- pci_dbg(dev, "%s failed with %d\n", method->name, rc);
- if (rc != -ENOTTY)
- return rc;
- }
-
- return -ENOTTY;
-}
-EXPORT_SYMBOL_GPL(__pci_reset_function_locked);
-
-/**
- * pci_init_reset_methods - check whether device can be safely reset
- * and store supported reset mechanisms.
- * @dev: PCI device to check for reset mechanisms
- *
- * Some devices allow an individual function to be reset without affecting
- * other functions in the same device. The PCI device must be in D0-D3hot
- * state.
- *
- * Stores reset mechanisms supported by device in reset_methods byte array
- * which is a member of struct pci_dev.
- */
-void pci_init_reset_methods(struct pci_dev *dev)
-{
- int m, i, rc;
-
- BUILD_BUG_ON(ARRAY_SIZE(pci_reset_fn_methods) != PCI_NUM_RESET_METHODS);
-
- might_sleep();
-
- i = 0;
- for (m = 1; m < PCI_NUM_RESET_METHODS; m++) {
- rc = pci_reset_fn_methods[m].reset_fn(dev, PCI_RESET_PROBE);
- if (!rc)
- dev->reset_methods[i++] = m;
- else if (rc != -ENOTTY)
- break;
- }
-
- dev->reset_methods[i] = 0;
-}
-
-/**
- * pci_reset_function - quiesce and reset a PCI device function
- * @dev: PCI device to reset
- *
- * Some devices allow an individual function to be reset without affecting
- * other functions in the same device. The PCI device must be responsive
- * to PCI config space in order to use this function.
- *
- * This function does not just reset the PCI portion of a device, but
- * clears all the state associated with the device. This function differs
- * from __pci_reset_function_locked() in that it saves and restores device state
- * over the reset and takes the PCI device lock.
- *
- * Returns 0 if the device function was successfully reset or negative if the
- * device doesn't support resetting a single function.
- */
-int pci_reset_function(struct pci_dev *dev)
-{
- struct pci_dev *bridge;
- int rc;
-
- if (!pci_reset_supported(dev))
- return -ENOTTY;
-
- /*
- * If there's no upstream bridge, no locking is needed since there is
- * no upstream bridge configuration to hold consistent.
- */
- bridge = pci_upstream_bridge(dev);
- if (bridge)
- pci_dev_lock(bridge);
-
- pci_dev_lock(dev);
- pci_dev_save_and_disable(dev);
-
- rc = __pci_reset_function_locked(dev);
-
- pci_dev_restore(dev);
- pci_dev_unlock(dev);
-
- if (bridge)
- pci_dev_unlock(bridge);
-
- return rc;
-}
-EXPORT_SYMBOL_GPL(pci_reset_function);
-
-/**
- * pci_reset_function_locked - quiesce and reset a PCI device function
- * @dev: PCI device to reset
- *
- * Some devices allow an individual function to be reset without affecting
- * other functions in the same device. The PCI device must be responsive
- * to PCI config space in order to use this function.
- *
- * This function does not just reset the PCI portion of a device, but
- * clears all the state associated with the device. This function differs
- * from __pci_reset_function_locked() in that it saves and restores device state
- * over the reset. It also differs from pci_reset_function() in that it
- * requires the PCI device lock to be held.
- *
- * Returns 0 if the device function was successfully reset or negative if the
- * device doesn't support resetting a single function.
- */
-int pci_reset_function_locked(struct pci_dev *dev)
-{
- int rc;
-
- if (!pci_reset_supported(dev))
- return -ENOTTY;
-
- pci_dev_save_and_disable(dev);
-
- rc = __pci_reset_function_locked(dev);
-
- pci_dev_restore(dev);
-
- return rc;
-}
-EXPORT_SYMBOL_GPL(pci_reset_function_locked);
-
-/**
- * pci_try_reset_function - quiesce and reset a PCI device function
- * @dev: PCI device to reset
- *
- * Same as above, except return -EAGAIN if unable to lock device.
- */
-int pci_try_reset_function(struct pci_dev *dev)
-{
- int rc;
-
- if (!pci_reset_supported(dev))
- return -ENOTTY;
-
- if (!pci_dev_trylock(dev))
- return -EAGAIN;
-
- pci_dev_save_and_disable(dev);
- rc = __pci_reset_function_locked(dev);
- pci_dev_restore(dev);
- pci_dev_unlock(dev);
-
- return rc;
-}
-EXPORT_SYMBOL_GPL(pci_try_reset_function);
-
-/* Do any devices on or below this bus prevent a bus reset? */
-static bool pci_bus_resettable(struct pci_bus *bus)
-{
- struct pci_dev *dev;
-
-
- if (bus->self && (bus->self->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET))
- return false;
-
- list_for_each_entry(dev, &bus->devices, bus_list) {
- if (!pci_reset_supported(dev))
- return false;
- if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
- (dev->subordinate && !pci_bus_resettable(dev->subordinate)))
- return false;
- }
-
- return true;
-}
-
-/* Lock devices from the top of the tree down */
-static void pci_bus_lock(struct pci_bus *bus)
-{
- struct pci_dev *dev;
-
- pci_dev_lock(bus->self);
- list_for_each_entry(dev, &bus->devices, bus_list) {
- if (dev->subordinate)
- pci_bus_lock(dev->subordinate);
- else
- pci_dev_lock(dev);
- }
-}
-
-/* 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);
- else
- pci_dev_unlock(dev);
- }
- pci_dev_unlock(bus->self);
-}
-
-/* Return 1 on successful lock, 0 on contention */
-static int pci_bus_trylock(struct pci_bus *bus)
-{
- struct pci_dev *dev;
-
- if (!pci_dev_trylock(bus->self))
- return 0;
-
- list_for_each_entry(dev, &bus->devices, bus_list) {
- if (dev->subordinate) {
- if (!pci_bus_trylock(dev->subordinate))
- goto unlock;
- } else if (!pci_dev_trylock(dev))
- goto unlock;
- }
- return 1;
-
-unlock:
- list_for_each_entry_continue_reverse(dev, &bus->devices, bus_list) {
- if (dev->subordinate)
- pci_bus_unlock(dev->subordinate);
- else
- pci_dev_unlock(dev);
- }
- pci_dev_unlock(bus->self);
- return 0;
-}
-
-/* Do any devices on or below this slot prevent a bus reset? */
-static bool pci_slot_resettable(struct pci_slot *slot)
-{
- struct pci_dev *dev;
-
- if (slot->bus->self &&
- (slot->bus->self->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET))
- return false;
-
- list_for_each_entry(dev, &slot->bus->devices, bus_list) {
- if (!dev->slot || dev->slot != slot)
- continue;
- if (!pci_reset_supported(dev))
- return false;
- if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
- (dev->subordinate && !pci_bus_resettable(dev->subordinate)))
- return false;
- }
-
- return true;
-}
-
-/* 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;
- if (dev->subordinate)
- pci_bus_lock(dev->subordinate);
- else
- pci_dev_lock(dev);
- }
-}
-
-/* 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);
- else
- pci_dev_unlock(dev);
- }
-}
-
-/* Return 1 on successful lock, 0 on contention */
-static int pci_slot_trylock(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) {
- if (!pci_bus_trylock(dev->subordinate)) {
- pci_dev_unlock(dev);
- goto unlock;
- }
- } else if (!pci_dev_trylock(dev))
- goto unlock;
- }
- return 1;
-
-unlock:
- list_for_each_entry_continue_reverse(dev,
- &slot->bus->devices, bus_list) {
- if (!dev->slot || dev->slot != slot)
- continue;
- if (dev->subordinate)
- pci_bus_unlock(dev->subordinate);
- else
- pci_dev_unlock(dev);
- }
- return 0;
-}
-
-/*
- * Save and disable devices from the top of the tree down while holding
- * the @dev mutex lock for the entire tree.
- */
-static void pci_bus_save_and_disable_locked(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_locked(dev->subordinate);
- }
-}
-
-/*
- * Restore devices from top of the tree down while holding @dev mutex lock
- * for the entire tree. Parent bridges need to be restored before we can
- * get to subordinate devices.
- */
-static void pci_bus_restore_locked(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_bridge_wait_for_secondary_bus(dev, "bus reset");
- pci_bus_restore_locked(dev->subordinate);
- }
- }
-}
-
-/*
- * Save and disable devices from the top of the tree down while holding
- * the @dev mutex lock for the entire tree.
- */
-static void pci_slot_save_and_disable_locked(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_locked(dev->subordinate);
- }
-}
-
-/*
- * Restore devices from top of the tree down while holding @dev mutex lock
- * for the entire tree. Parent bridges need to be restored before we can
- * get to subordinate devices.
- */
-static void pci_slot_restore_locked(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_bridge_wait_for_secondary_bus(dev, "slot reset");
- pci_bus_restore_locked(dev->subordinate);
- }
- }
-}
-
-static int pci_slot_reset(struct pci_slot *slot, bool probe)
-{
- int rc;
-
- if (!slot || !pci_slot_resettable(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, PCI_RESET_PROBE);
-}
-EXPORT_SYMBOL_GPL(pci_probe_reset_slot);
-
-/**
- * __pci_reset_slot - Try to 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.
- *
- * Same as above except return -EAGAIN if the slot cannot be locked
- */
-static int __pci_reset_slot(struct pci_slot *slot)
-{
- int rc;
-
- rc = pci_slot_reset(slot, PCI_RESET_PROBE);
- if (rc)
- return rc;
-
- if (pci_slot_trylock(slot)) {
- pci_slot_save_and_disable_locked(slot);
- might_sleep();
- rc = pci_reset_hotplug_slot(slot->hotplug, PCI_RESET_DO_RESET);
- pci_slot_restore_locked(slot);
- pci_slot_unlock(slot);
- } else
- rc = -EAGAIN;
-
- return rc;
-}
-
-static int pci_bus_reset(struct pci_bus *bus, bool probe)
-{
- int ret;
-
- if (!bus->self || !pci_bus_resettable(bus))
- return -ENOTTY;
-
- if (probe)
- return 0;
-
- pci_bus_lock(bus);
-
- might_sleep();
-
- ret = pci_bridge_secondary_bus_reset(bus->self);
-
- pci_bus_unlock(bus);
-
- return ret;
-}
-
-/**
- * pci_bus_error_reset - reset the bridge's subordinate bus
- * @bridge: The parent device that connects to the bus to reset
- *
- * This function will first try to reset the slots on this bus if the method is
- * available. If slot reset fails or is not available, this will fall back to a
- * secondary bus reset.
- */
-int pci_bus_error_reset(struct pci_dev *bridge)
-{
- struct pci_bus *bus = bridge->subordinate;
- struct pci_slot *slot;
-
- if (!bus)
- return -ENOTTY;
-
- mutex_lock(&pci_slot_mutex);
- if (list_empty(&bus->slots))
- goto bus_reset;
-
- list_for_each_entry(slot, &bus->slots, list)
- if (pci_probe_reset_slot(slot))
- goto bus_reset;
-
- list_for_each_entry(slot, &bus->slots, list)
- if (pci_slot_reset(slot, PCI_RESET_DO_RESET))
- goto bus_reset;
-
- mutex_unlock(&pci_slot_mutex);
- return 0;
-bus_reset:
- mutex_unlock(&pci_slot_mutex);
- return pci_bus_reset(bridge->subordinate, PCI_RESET_DO_RESET);
-}
-
-/**
- * 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, PCI_RESET_PROBE);
-}
-EXPORT_SYMBOL_GPL(pci_probe_reset_bus);
-
-/**
- * __pci_reset_bus - Try to reset a PCI bus
- * @bus: top level PCI bus to reset
- *
- * Same as above except return -EAGAIN if the bus cannot be locked
- */
-int __pci_reset_bus(struct pci_bus *bus)
-{
- int rc;
-
- rc = pci_bus_reset(bus, PCI_RESET_PROBE);
- if (rc)
- return rc;
-
- if (pci_bus_trylock(bus)) {
- pci_bus_save_and_disable_locked(bus);
- might_sleep();
- rc = pci_bridge_secondary_bus_reset(bus->self);
- pci_bus_restore_locked(bus);
- pci_bus_unlock(bus);
- } else
- rc = -EAGAIN;
-
- return rc;
-}
-
-/**
- * pci_reset_bus - Try to reset a PCI bus
- * @pdev: top level PCI device to reset via slot/bus
- *
- * Same as above except return -EAGAIN if the bus cannot be locked
- */
-int pci_reset_bus(struct pci_dev *pdev)
-{
- return (!pci_probe_reset_slot(pdev->slot)) ?
- __pci_reset_slot(pdev->slot) : __pci_reset_bus(pdev->bus);
-}
-EXPORT_SYMBOL_GPL(pci_reset_bus);
-
/**
* pcix_get_max_mmrbc - get PCI-X maximum designed memory read byte count
* @dev: PCI device to query
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index b81e99cd4b62..10b96bfd9a72 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -46,6 +46,14 @@ struct pcie_tlp_log;
*/
#define PCIE_PME_TO_L2_TIMEOUT_US 10000
+/*
+ * Devices may extend the 1 sec period through Request Retry Status
+ * completions (PCIe r6.0 sec 2.3.1). The spec does not provide an upper
+ * limit, but 60 sec ought to be enough for any device to become
+ * responsive.
+ */
+#define PCIE_RESET_READY_POLL_MS 60000 /* msec */
+
/*
* PCIe r6.0, sec 6.6.1 <Conventional Reset>
*
@@ -154,7 +162,9 @@ void pci_msi_init(struct pci_dev *dev);
void pci_msix_init(struct pci_dev *dev);
bool pci_bridge_d3_possible(struct pci_dev *dev);
void pci_bridge_d3_update(struct pci_dev *dev);
+void pci_dev_d3_sleep(struct pci_dev *dev);
int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type);
+int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout);
static inline bool pci_bus_rrs_vendor_id(u32 l)
{
diff --git a/drivers/pci/reset-restore.c b/drivers/pci/reset-restore.c
new file mode 100644
index 000000000000..c0e2b0aa0f1a
--- /dev/null
+++ b/drivers/pci/reset-restore.c
@@ -0,0 +1,1014 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCI Reset and Restore Logic
+ */
+
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/pci.h>
+#include <linux/pci_hotplug.h>
+
+#include "pci.h"
+
+bool pci_reset_supported(struct pci_dev *dev)
+{
+ return dev->reset_methods[0] != 0;
+}
+
+/**
+ * pcibios_set_pcie_reset_state - set reset state for device dev
+ * @dev: the PCIe device reset
+ * @state: Reset state to enter into
+ *
+ * Set the PCIe reset state for the device. This is the default
+ * implementation. Architecture implementations can override this.
+ */
+int __weak pcibios_set_pcie_reset_state(struct pci_dev *dev,
+ enum pcie_reset_state state)
+{
+ return -EINVAL;
+}
+
+/**
+ * pci_set_pcie_reset_state - set reset state for device dev
+ * @dev: the PCIe device reset
+ * @state: Reset state to enter into
+ *
+ * Sets the PCI reset state for the device.
+ */
+int pci_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
+{
+ return pcibios_set_pcie_reset_state(dev, state);
+}
+EXPORT_SYMBOL_GPL(pci_set_pcie_reset_state);
+
+/**
+ * pcie_flr - initiate a PCIe function level reset
+ * @dev: device to reset
+ *
+ * Initiate a function level reset unconditionally on @dev without
+ * checking any flags and DEVCAP
+ */
+int pcie_flr(struct pci_dev *dev)
+{
+ if (!pci_wait_for_pending_transaction(dev))
+ pci_err(dev, "timed out waiting for pending transaction; performing function level reset anyway\n");
+
+ pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_BCR_FLR);
+
+ if (dev->imm_ready)
+ return 0;
+
+ /*
+ * Per PCIe r4.0, sec 6.6.2, a device must complete an FLR within
+ * 100ms, but may silently discard requests while the FLR is in
+ * progress. Wait 100ms before trying to access the device.
+ */
+ msleep(100);
+
+ return pci_dev_wait(dev, "FLR", PCIE_RESET_READY_POLL_MS);
+}
+EXPORT_SYMBOL_GPL(pcie_flr);
+
+/**
+ * pcie_reset_flr - initiate a PCIe function level reset
+ * @dev: device to reset
+ * @probe: if true, return 0 if device can be reset this way
+ *
+ * Initiate a function level reset on @dev.
+ */
+int pcie_reset_flr(struct pci_dev *dev, bool probe)
+{
+ if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
+ return -ENOTTY;
+
+ if (!(dev->devcap & PCI_EXP_DEVCAP_FLR))
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ return pcie_flr(dev);
+}
+EXPORT_SYMBOL_GPL(pcie_reset_flr);
+
+static int pci_af_flr(struct pci_dev *dev, bool probe)
+{
+ int pos;
+ u8 cap;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_AF);
+ if (!pos)
+ return -ENOTTY;
+
+ if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
+ return -ENOTTY;
+
+ pci_read_config_byte(dev, pos + PCI_AF_CAP, &cap);
+ if (!(cap & PCI_AF_CAP_TP) || !(cap & PCI_AF_CAP_FLR))
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ /*
+ * Wait for Transaction Pending bit to clear. A word-aligned test
+ * is used, so we use the control offset rather than status and shift
+ * the test bit to match.
+ */
+ if (!pci_wait_for_pending(dev, pos + PCI_AF_CTRL,
+ PCI_AF_STATUS_TP << 8))
+ pci_err(dev, "timed out waiting for pending transaction; performing AF function level reset anyway\n");
+
+ pci_write_config_byte(dev, pos + PCI_AF_CTRL, PCI_AF_CTRL_FLR);
+
+ if (dev->imm_ready)
+ return 0;
+
+ /*
+ * Per Advanced Capabilities for Conventional PCI ECN, 13 April 2006,
+ * updated 27 July 2006; a device must complete an FLR within
+ * 100ms, but may silently discard requests while the FLR is in
+ * progress. Wait 100ms before trying to access the device.
+ */
+ msleep(100);
+
+ return pci_dev_wait(dev, "AF_FLR", PCIE_RESET_READY_POLL_MS);
+}
+
+/**
+ * pci_pm_reset - Put device into PCI_D3 and back into PCI_D0.
+ * @dev: Device to reset.
+ * @probe: if true, return 0 if the device can be reset this way.
+ *
+ * If @dev supports native PCI PM and its PCI_PM_CTRL_NO_SOFT_RESET flag is
+ * unset, it will be reinitialized internally when going from PCI_D3hot to
+ * PCI_D0. If that's the case and the device is not in a low-power state
+ * already, force it into PCI_D3hot and back to PCI_D0, causing it to be reset.
+ *
+ * NOTE: This causes the caller to sleep for twice the device power transition
+ * cooldown period, which for the D0->D3hot and D3hot->D0 transitions is 10 ms
+ * by default (i.e. unless the @dev's d3hot_delay field has a different value).
+ * Moreover, only devices in D0 can be reset by this function.
+ */
+static int pci_pm_reset(struct pci_dev *dev, bool probe)
+{
+ u16 csr;
+
+ if (!dev->pm_cap || dev->dev_flags & PCI_DEV_FLAGS_NO_PM_RESET)
+ return -ENOTTY;
+
+ pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &csr);
+ if (csr & PCI_PM_CTRL_NO_SOFT_RESET)
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ if (dev->current_state != PCI_D0)
+ return -EINVAL;
+
+ csr &= ~PCI_PM_CTRL_STATE_MASK;
+ csr |= PCI_D3hot;
+ pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, csr);
+ pci_dev_d3_sleep(dev);
+
+ csr &= ~PCI_PM_CTRL_STATE_MASK;
+ csr |= PCI_D0;
+ pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, csr);
+ pci_dev_d3_sleep(dev);
+
+ return pci_dev_wait(dev, "PM D3hot->D0", PCIE_RESET_READY_POLL_MS);
+}
+
+void pci_reset_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 minimum requirement.
+ */
+ msleep(2);
+
+ ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
+ pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
+}
+
+void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
+{
+ pci_reset_secondary_bus(dev);
+}
+
+/**
+ * pci_bridge_secondary_bus_reset - 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.
+ */
+int pci_bridge_secondary_bus_reset(struct pci_dev *dev)
+{
+ if (!dev->block_cfg_access)
+ pci_warn_once(dev, "unlocked secondary bus reset via: %pS\n",
+ __builtin_return_address(0));
+ pcibios_reset_secondary_bus(dev);
+
+ return pci_bridge_wait_for_secondary_bus(dev, "bus reset");
+}
+EXPORT_SYMBOL_GPL(pci_bridge_secondary_bus_reset);
+
+static int pci_parent_bus_reset(struct pci_dev *dev, bool probe)
+{
+ struct pci_dev *pdev;
+
+ if (pci_is_root_bus(dev->bus) || dev->subordinate ||
+ !dev->bus->self || dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
+ return -ENOTTY;
+
+ list_for_each_entry(pdev, &dev->bus->devices, bus_list)
+ if (pdev != dev)
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ return pci_bridge_secondary_bus_reset(dev->bus->self);
+}
+
+static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, bool probe)
+{
+ int rc = -ENOTTY;
+
+ if (!hotplug || !try_module_get(hotplug->owner))
+ return rc;
+
+ if (hotplug->ops->reset_slot)
+ rc = hotplug->ops->reset_slot(hotplug, probe);
+
+ module_put(hotplug->owner);
+
+ return rc;
+}
+
+static int pci_dev_reset_slot_function(struct pci_dev *dev, bool probe)
+{
+ if (dev->multifunction || dev->subordinate || !dev->slot ||
+ dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
+ return -ENOTTY;
+
+ return pci_reset_hotplug_slot(dev->slot->hotplug, probe);
+}
+
+static u16 cxl_port_dvsec(struct pci_dev *dev)
+{
+ return pci_find_dvsec_capability(dev, PCI_VENDOR_ID_CXL,
+ PCI_DVSEC_CXL_PORT);
+}
+
+static bool cxl_sbr_masked(struct pci_dev *dev)
+{
+ u16 dvsec, reg;
+ int rc;
+
+ dvsec = cxl_port_dvsec(dev);
+ if (!dvsec)
+ return false;
+
+ rc = pci_read_config_word(dev, dvsec + PCI_DVSEC_CXL_PORT_CTL, ®);
+ if (rc || PCI_POSSIBLE_ERROR(reg))
+ return false;
+
+ /*
+ * Per CXL spec r3.1, sec 8.1.5.2, when "Unmask SBR" is 0, the SBR
+ * bit in Bridge Control has no effect. When 1, the Port generates
+ * hot reset when the SBR bit is set to 1.
+ */
+ if (reg & PCI_DVSEC_CXL_PORT_CTL_UNMASK_SBR)
+ return false;
+
+ return true;
+}
+
+static int pci_reset_bus_function(struct pci_dev *dev, bool probe)
+{
+ struct pci_dev *bridge = pci_upstream_bridge(dev);
+ int rc;
+
+ /*
+ * If "dev" is below a CXL port that has SBR control masked, SBR
+ * won't do anything, so return error.
+ */
+ if (bridge && cxl_sbr_masked(bridge)) {
+ if (probe)
+ return 0;
+
+ return -ENOTTY;
+ }
+
+ rc = pci_dev_reset_slot_function(dev, probe);
+ if (rc != -ENOTTY)
+ return rc;
+ return pci_parent_bus_reset(dev, probe);
+}
+
+static int cxl_reset_bus_function(struct pci_dev *dev, bool probe)
+{
+ struct pci_dev *bridge;
+ u16 dvsec, reg, val;
+ int rc;
+
+ bridge = pci_upstream_bridge(dev);
+ if (!bridge)
+ return -ENOTTY;
+
+ dvsec = cxl_port_dvsec(bridge);
+ if (!dvsec)
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ rc = pci_read_config_word(bridge, dvsec + PCI_DVSEC_CXL_PORT_CTL, ®);
+ if (rc)
+ return -ENOTTY;
+
+ if (reg & PCI_DVSEC_CXL_PORT_CTL_UNMASK_SBR) {
+ val = reg;
+ } else {
+ val = reg | PCI_DVSEC_CXL_PORT_CTL_UNMASK_SBR;
+ pci_write_config_word(bridge, dvsec + PCI_DVSEC_CXL_PORT_CTL,
+ val);
+ }
+
+ rc = pci_reset_bus_function(dev, probe);
+
+ if (reg != val)
+ pci_write_config_word(bridge, dvsec + PCI_DVSEC_CXL_PORT_CTL,
+ reg);
+
+ return rc;
+}
+
+/* dev->reset_methods[] is a 0-terminated list of indices into this array */
+const struct pci_reset_fn_method pci_reset_fn_methods[] = {
+ { },
+ { pci_dev_specific_reset, .name = "device_specific" },
+ { pci_dev_acpi_reset, .name = "acpi" },
+ { pcie_reset_flr, .name = "flr" },
+ { pci_af_flr, .name = "af_flr" },
+ { pci_pm_reset, .name = "pm" },
+ { pci_reset_bus_function, .name = "bus" },
+ { cxl_reset_bus_function, .name = "cxl_bus" },
+};
+
+/**
+ * __pci_reset_function_locked - reset a PCI device function while holding
+ * the @dev mutex lock.
+ * @dev: PCI device to reset
+ *
+ * Some devices allow an individual function to be reset without affecting
+ * other functions in the same device. The PCI device must be responsive
+ * to PCI config space in order to use this function.
+ *
+ * The device function is presumed to be unused and the caller is holding
+ * the device mutex lock when this function is called.
+ *
+ * Resetting the device will make the contents of PCI configuration space
+ * random, so any caller of this must be prepared to reinitialise the
+ * device including MSI, bus mastering, BARs, decoding IO and memory spaces,
+ * etc.
+ *
+ * Returns 0 if the device function was successfully reset or negative if the
+ * device doesn't support resetting a single function.
+ */
+int __pci_reset_function_locked(struct pci_dev *dev)
+{
+ int i, m, rc;
+ const struct pci_reset_fn_method *method;
+
+ might_sleep();
+
+ /*
+ * A reset method returns -ENOTTY if it doesn't support this device and
+ * we should try the next method.
+ *
+ * If it returns 0 (success), we're finished. If it returns any other
+ * error, we're also finished: this indicates that further reset
+ * mechanisms might be broken on the device.
+ */
+ for (i = 0; i < PCI_NUM_RESET_METHODS; i++) {
+ m = dev->reset_methods[i];
+ if (!m)
+ return -ENOTTY;
+
+ method = &pci_reset_fn_methods[m];
+ pci_dbg(dev, "reset via %s\n", method->name);
+ rc = method->reset_fn(dev, PCI_RESET_DO_RESET);
+ if (!rc)
+ return 0;
+
+ pci_dbg(dev, "%s failed with %d\n", method->name, rc);
+ if (rc != -ENOTTY)
+ return rc;
+ }
+
+ return -ENOTTY;
+}
+EXPORT_SYMBOL_GPL(__pci_reset_function_locked);
+
+/**
+ * pci_init_reset_methods - check whether device can be safely reset
+ * and store supported reset mechanisms.
+ * @dev: PCI device to check for reset mechanisms
+ *
+ * Some devices allow an individual function to be reset without affecting
+ * other functions in the same device. The PCI device must be in D0-D3hot
+ * state.
+ *
+ * Stores reset mechanisms supported by device in reset_methods byte array
+ * which is a member of struct pci_dev.
+ */
+void pci_init_reset_methods(struct pci_dev *dev)
+{
+ int m, i, rc;
+
+ BUILD_BUG_ON(ARRAY_SIZE(pci_reset_fn_methods) != PCI_NUM_RESET_METHODS);
+
+ might_sleep();
+
+ i = 0;
+ for (m = 1; m < PCI_NUM_RESET_METHODS; m++) {
+ rc = pci_reset_fn_methods[m].reset_fn(dev, PCI_RESET_PROBE);
+ if (!rc)
+ dev->reset_methods[i++] = m;
+ else if (rc != -ENOTTY)
+ break;
+ }
+
+ dev->reset_methods[i] = 0;
+}
+
+static void pci_dev_save_and_disable(struct pci_dev *dev)
+{
+ const struct pci_error_handlers *err_handler =
+ dev->driver ? dev->driver->err_handler : NULL;
+
+ /*
+ * dev->driver->err_handler->reset_prepare() is protected against
+ * races with ->remove() by the device lock, which must be held by
+ * the caller.
+ */
+ if (err_handler && err_handler->reset_prepare)
+ err_handler->reset_prepare(dev);
+ else if (dev->driver)
+ pci_warn(dev, "resetting");
+
+ /*
+ * 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)
+{
+ const struct pci_error_handlers *err_handler =
+ dev->driver ? dev->driver->err_handler : NULL;
+
+ pci_restore_state(dev);
+
+ /*
+ * dev->driver->err_handler->reset_done() is protected against
+ * races with ->remove() by the device lock, which must be held by
+ * the caller.
+ */
+ if (err_handler && err_handler->reset_done)
+ err_handler->reset_done(dev);
+ else if (dev->driver)
+ pci_warn(dev, "reset done");
+}
+
+/**
+ * pci_reset_function - quiesce and reset a PCI device function
+ * @dev: PCI device to reset
+ *
+ * Some devices allow an individual function to be reset without affecting
+ * other functions in the same device. The PCI device must be responsive
+ * to PCI config space in order to use this function.
+ *
+ * This function does not just reset the PCI portion of a device, but
+ * clears all the state associated with the device. This function differs
+ * from __pci_reset_function_locked() in that it saves and restores device state
+ * over the reset and takes the PCI device lock.
+ *
+ * Returns 0 if the device function was successfully reset or negative if the
+ * device doesn't support resetting a single function.
+ */
+int pci_reset_function(struct pci_dev *dev)
+{
+ struct pci_dev *bridge;
+ int rc;
+
+ if (!pci_reset_supported(dev))
+ return -ENOTTY;
+
+ /*
+ * If there's no upstream bridge, no locking is needed since there is
+ * no upstream bridge configuration to hold consistent.
+ */
+ bridge = pci_upstream_bridge(dev);
+ if (bridge)
+ pci_dev_lock(bridge);
+
+ pci_dev_lock(dev);
+ pci_dev_save_and_disable(dev);
+
+ rc = __pci_reset_function_locked(dev);
+
+ pci_dev_restore(dev);
+ pci_dev_unlock(dev);
+
+ if (bridge)
+ pci_dev_unlock(bridge);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(pci_reset_function);
+
+/**
+ * pci_reset_function_locked - quiesce and reset a PCI device function
+ * @dev: PCI device to reset
+ *
+ * Some devices allow an individual function to be reset without affecting
+ * other functions in the same device. The PCI device must be responsive
+ * to PCI config space in order to use this function.
+ *
+ * This function does not just reset the PCI portion of a device, but
+ * clears all the state associated with the device. This function differs
+ * from __pci_reset_function_locked() in that it saves and restores device state
+ * over the reset. It also differs from pci_reset_function() in that it
+ * requires the PCI device lock to be held.
+ *
+ * Returns 0 if the device function was successfully reset or negative if the
+ * device doesn't support resetting a single function.
+ */
+int pci_reset_function_locked(struct pci_dev *dev)
+{
+ int rc;
+
+ if (!pci_reset_supported(dev))
+ return -ENOTTY;
+
+ pci_dev_save_and_disable(dev);
+
+ rc = __pci_reset_function_locked(dev);
+
+ pci_dev_restore(dev);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(pci_reset_function_locked);
+
+/**
+ * pci_try_reset_function - quiesce and reset a PCI device function
+ * @dev: PCI device to reset
+ *
+ * Same as above, except return -EAGAIN if unable to lock device.
+ */
+int pci_try_reset_function(struct pci_dev *dev)
+{
+ int rc;
+
+ if (!pci_reset_supported(dev))
+ return -ENOTTY;
+
+ if (!pci_dev_trylock(dev))
+ return -EAGAIN;
+
+ pci_dev_save_and_disable(dev);
+ rc = __pci_reset_function_locked(dev);
+ pci_dev_restore(dev);
+ pci_dev_unlock(dev);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(pci_try_reset_function);
+
+/* Do any devices on or below this bus prevent a bus reset? */
+static bool pci_bus_resettable(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+
+ if (bus->self && (bus->self->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET))
+ return false;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ if (!pci_reset_supported(dev))
+ return false;
+ if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
+ (dev->subordinate && !pci_bus_resettable(dev->subordinate)))
+ return false;
+ }
+
+ return true;
+}
+
+/* Lock devices from the top of the tree down */
+static void pci_bus_lock(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+
+ pci_dev_lock(bus->self);
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ if (dev->subordinate)
+ pci_bus_lock(dev->subordinate);
+ else
+ pci_dev_lock(dev);
+ }
+}
+
+/* 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);
+ else
+ pci_dev_unlock(dev);
+ }
+ pci_dev_unlock(bus->self);
+}
+
+/* Return 1 on successful lock, 0 on contention */
+static int pci_bus_trylock(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+
+ if (!pci_dev_trylock(bus->self))
+ return 0;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ if (dev->subordinate) {
+ if (!pci_bus_trylock(dev->subordinate))
+ goto unlock;
+ } else if (!pci_dev_trylock(dev))
+ goto unlock;
+ }
+ return 1;
+
+unlock:
+ list_for_each_entry_continue_reverse(dev, &bus->devices, bus_list) {
+ if (dev->subordinate)
+ pci_bus_unlock(dev->subordinate);
+ else
+ pci_dev_unlock(dev);
+ }
+ pci_dev_unlock(bus->self);
+ return 0;
+}
+
+/* Do any devices on or below this slot prevent a bus reset? */
+static bool pci_slot_resettable(struct pci_slot *slot)
+{
+ struct pci_dev *dev;
+
+ if (slot->bus->self &&
+ (slot->bus->self->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET))
+ return false;
+
+ list_for_each_entry(dev, &slot->bus->devices, bus_list) {
+ if (!dev->slot || dev->slot != slot)
+ continue;
+ if (!pci_reset_supported(dev))
+ return false;
+ if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
+ (dev->subordinate && !pci_bus_resettable(dev->subordinate)))
+ return false;
+ }
+
+ return true;
+}
+
+/* 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;
+ if (dev->subordinate)
+ pci_bus_lock(dev->subordinate);
+ else
+ pci_dev_lock(dev);
+ }
+}
+
+/* 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);
+ else
+ pci_dev_unlock(dev);
+ }
+}
+
+/* Return 1 on successful lock, 0 on contention */
+static int pci_slot_trylock(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) {
+ if (!pci_bus_trylock(dev->subordinate)) {
+ pci_dev_unlock(dev);
+ goto unlock;
+ }
+ } else if (!pci_dev_trylock(dev))
+ goto unlock;
+ }
+ return 1;
+
+unlock:
+ list_for_each_entry_continue_reverse(dev,
+ &slot->bus->devices, bus_list) {
+ if (!dev->slot || dev->slot != slot)
+ continue;
+ if (dev->subordinate)
+ pci_bus_unlock(dev->subordinate);
+ else
+ pci_dev_unlock(dev);
+ }
+ return 0;
+}
+
+/*
+ * Save and disable devices from the top of the tree down while holding
+ * the @dev mutex lock for the entire tree.
+ */
+static void pci_bus_save_and_disable_locked(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_locked(dev->subordinate);
+ }
+}
+
+/*
+ * Restore devices from top of the tree down while holding @dev mutex lock
+ * for the entire tree. Parent bridges need to be restored before we can
+ * get to subordinate devices.
+ */
+static void pci_bus_restore_locked(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_bridge_wait_for_secondary_bus(dev, "bus reset");
+ pci_bus_restore_locked(dev->subordinate);
+ }
+ }
+}
+
+/*
+ * Save and disable devices from the top of the tree down while holding
+ * the @dev mutex lock for the entire tree.
+ */
+static void pci_slot_save_and_disable_locked(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_locked(dev->subordinate);
+ }
+}
+
+/*
+ * Restore devices from top of the tree down while holding @dev mutex lock
+ * for the entire tree. Parent bridges need to be restored before we can
+ * get to subordinate devices.
+ */
+static void pci_slot_restore_locked(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_bridge_wait_for_secondary_bus(dev, "slot reset");
+ pci_bus_restore_locked(dev->subordinate);
+ }
+ }
+}
+
+static int pci_slot_reset(struct pci_slot *slot, bool probe)
+{
+ int rc;
+
+ if (!slot || !pci_slot_resettable(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, PCI_RESET_PROBE);
+}
+EXPORT_SYMBOL_GPL(pci_probe_reset_slot);
+
+/**
+ * __pci_reset_slot - Try to 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.
+ *
+ * Same as above except return -EAGAIN if the slot cannot be locked
+ */
+static int __pci_reset_slot(struct pci_slot *slot)
+{
+ int rc;
+
+ rc = pci_slot_reset(slot, PCI_RESET_PROBE);
+ if (rc)
+ return rc;
+
+ if (pci_slot_trylock(slot)) {
+ pci_slot_save_and_disable_locked(slot);
+ might_sleep();
+ rc = pci_reset_hotplug_slot(slot->hotplug, PCI_RESET_DO_RESET);
+ pci_slot_restore_locked(slot);
+ pci_slot_unlock(slot);
+ } else
+ rc = -EAGAIN;
+
+ return rc;
+}
+
+static int pci_bus_reset(struct pci_bus *bus, bool probe)
+{
+ int ret;
+
+ if (!bus->self || !pci_bus_resettable(bus))
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ pci_bus_lock(bus);
+
+ might_sleep();
+
+ ret = pci_bridge_secondary_bus_reset(bus->self);
+
+ pci_bus_unlock(bus);
+
+ return ret;
+}
+
+/**
+ * pci_bus_error_reset - reset the bridge's subordinate bus
+ * @bridge: The parent device that connects to the bus to reset
+ *
+ * This function will first try to reset the slots on this bus if the method is
+ * available. If slot reset fails or is not available, this will fall back to a
+ * secondary bus reset.
+ */
+int pci_bus_error_reset(struct pci_dev *bridge)
+{
+ struct pci_bus *bus = bridge->subordinate;
+ struct pci_slot *slot;
+
+ if (!bus)
+ return -ENOTTY;
+
+ mutex_lock(&pci_slot_mutex);
+ if (list_empty(&bus->slots))
+ goto bus_reset;
+
+ list_for_each_entry(slot, &bus->slots, list)
+ if (pci_probe_reset_slot(slot))
+ goto bus_reset;
+
+ list_for_each_entry(slot, &bus->slots, list)
+ if (pci_slot_reset(slot, PCI_RESET_DO_RESET))
+ goto bus_reset;
+
+ mutex_unlock(&pci_slot_mutex);
+ return 0;
+bus_reset:
+ mutex_unlock(&pci_slot_mutex);
+ return pci_bus_reset(bridge->subordinate, PCI_RESET_DO_RESET);
+}
+
+/**
+ * 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, PCI_RESET_PROBE);
+}
+EXPORT_SYMBOL_GPL(pci_probe_reset_bus);
+
+/**
+ * __pci_reset_bus - Try to reset a PCI bus
+ * @bus: top level PCI bus to reset
+ *
+ * Same as above except return -EAGAIN if the bus cannot be locked
+ */
+int __pci_reset_bus(struct pci_bus *bus)
+{
+ int rc;
+
+ rc = pci_bus_reset(bus, PCI_RESET_PROBE);
+ if (rc)
+ return rc;
+
+ if (pci_bus_trylock(bus)) {
+ pci_bus_save_and_disable_locked(bus);
+ might_sleep();
+ rc = pci_bridge_secondary_bus_reset(bus->self);
+ pci_bus_restore_locked(bus);
+ pci_bus_unlock(bus);
+ } else
+ rc = -EAGAIN;
+
+ return rc;
+}
+
+/**
+ * pci_reset_bus - Try to reset a PCI bus
+ * @pdev: top level PCI device to reset via slot/bus
+ *
+ * Same as above except return -EAGAIN if the bus cannot be locked
+ */
+int pci_reset_bus(struct pci_dev *pdev)
+{
+ return (!pci_probe_reset_slot(pdev->slot)) ?
+ __pci_reset_slot(pdev->slot) : __pci_reset_bus(pdev->bus);
+}
+EXPORT_SYMBOL_GPL(pci_reset_bus);
base-commit: f3efb9569b4a21354ef2caf7ab0608a3e14cc6e4
--
2.39.5
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