From ab4b8a47abeefad94cdb6b4c0df6a13f4f6ae4e0 Mon Sep 17 00:00:00 2001 From: Piotr Gregor Date: Wed, 2 Aug 2017 20:42:18 +0100 Subject: PCI/PM: Expand description of pci_set_power_state() Add two reasons for returning 0 value to the description of pci_set_power_state() to include the cases when: - the transition is to D1 or D2 but D1 and D2 are not supported - the transition is to D3 but D3 is not supported Signed-off-by: Piotr Gregor Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index af0cc3456dc1..9528781db4d3 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -892,7 +892,9 @@ EXPORT_SYMBOL_GPL(__pci_complete_power_transition); * -EINVAL if the requested state is invalid. * -EIO if device does not support PCI PM or its PM capabilities register has a * wrong version, or device doesn't support the requested state. + * 0 if the transition is to D1 or D2 but D1 and D2 are not supported. * 0 if device already is in the requested state. + * 0 if the transition is to D3 but D3 is not supported. * 0 if device's power state has been successfully changed. */ int pci_set_power_state(struct pci_dev *dev, pci_power_t state) -- cgit v1.2.3 From 40f11adc7cd9281227f0a6a627d966dd0a5f0cd9 Mon Sep 17 00:00:00 2001 From: Srinath Mannam Date: Fri, 18 Aug 2017 21:50:48 -0500 Subject: PCI: Avoid race while enabling upstream bridges When we enable a device, we first enable any upstream bridges. If a bridge has multiple downstream devices and we enable them simultaneously, the race to enable the upstream bridge may cause problems. Consider this hierarchy: bridge A --+-- device B +-- device C If drivers for B and C call pci_enable_device() simultaneously, both will attempt to enable A, which involves setting PCI_COMMAND_MASTER via pci_set_master() and PCI_COMMAND_MEMORY via pci_enable_resources(). In the following sequence, B's update to set A's PCI_COMMAND_MEMORY is lost, and neither B nor C will work correctly: B C pci_set_master(A) cmd = read(A, PCI_COMMAND) cmd |= PCI_COMMAND_MASTER pci_set_master(A) cmd = read(A, PCI_COMMAND) cmd |= PCI_COMMAND_MASTER write(A, PCI_COMMAND, cmd) pci_enable_device(A) pci_enable_resources(A) cmd = read(A, PCI_COMMAND) cmd |= PCI_COMMAND_MEMORY write(A, PCI_COMMAND, cmd) write(A, PCI_COMMAND, cmd) Avoid this race by holding a new pci_bridge_mutex while enabling a bridge. This ensures that both PCI_COMMAND_MASTER and PCI_COMMAND_MEMORY will be updated before another thread can start enabling the bridge. Note that although pci_enable_bridge() is recursive, it enables any upstream bridges *before* acquiring the mutex. When it acquires the mutex and calls pci_set_master() and pci_enable_device(), any upstream bridges have already been enabled so pci_enable_device() will not deadlock by calling pci_enable_bridge() again. Signed-off-by: Srinath Mannam [bhelgaas: changelog, comment] Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index af0cc3456dc1..7cb29a223b73 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -52,6 +52,7 @@ static void pci_pme_list_scan(struct work_struct *work); static LIST_HEAD(pci_pme_list); static DEFINE_MUTEX(pci_pme_list_mutex); static DECLARE_DELAYED_WORK(pci_pme_work, pci_pme_list_scan); +static DEFINE_MUTEX(pci_bridge_mutex); struct pci_pme_device { struct list_head list; @@ -1348,10 +1349,16 @@ static void pci_enable_bridge(struct pci_dev *dev) if (bridge) pci_enable_bridge(bridge); + /* + * Hold pci_bridge_mutex to prevent a race when enabling two + * devices below the bridge simultaneously. The race may cause a + * PCI_COMMAND_MEMORY update to be lost (see changelog). + */ + mutex_lock(&pci_bridge_mutex); if (pci_is_enabled(dev)) { if (!dev->is_busmaster) pci_set_master(dev); - return; + goto end; } retval = pci_enable_device(dev); @@ -1359,6 +1366,8 @@ static void pci_enable_bridge(struct pci_dev *dev) dev_err(&dev->dev, "Error enabling bridge (%d), continuing\n", retval); pci_set_master(dev); +end: + mutex_unlock(&pci_bridge_mutex); } static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags) @@ -1383,7 +1392,7 @@ static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags) return 0; /* already enabled */ bridge = pci_upstream_bridge(dev); - if (bridge) + if (bridge && !pci_is_enabled(bridge)) pci_enable_bridge(bridge); /* only skip sriov related */ -- cgit v1.2.3 From b63773a801ff7f7f047894a9be23616f4491aca8 Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Tue, 18 Jul 2017 16:43:21 -0500 Subject: PCI: Convert to using %pOF instead of full_name() Now that we have a custom printf format specifier, convert users of full_name() to use %pOF instead. This is preparation for removing storing of the full path string for each node. Signed-off-by: Rob Herring Signed-off-by: Bjorn Helgaas Reviewed-by: Tyrel Datwyler Cc: Thomas Petazzoni Cc: Jason Cooper Cc: Thierry Reding Cc: Jonathan Hunter Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman --- drivers/pci/host/pci-mvebu.c | 8 ++++---- drivers/pci/host/pci-tegra.c | 3 +-- drivers/pci/hotplug/pnv_php.c | 4 ++-- drivers/pci/hotplug/rpadlpar_core.c | 4 ++-- drivers/pci/hotplug/rpaphp_core.c | 2 +- drivers/pci/hotplug/rpaphp_pci.c | 4 ++-- drivers/pci/hotplug/rpaphp_slot.c | 4 ++-- drivers/pci/pci-sysfs.c | 4 ++-- drivers/pci/pci.c | 4 ++-- 9 files changed, 18 insertions(+), 19 deletions(-) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c index f353a6eb2f01..424982997eb9 100644 --- a/drivers/pci/host/pci-mvebu.c +++ b/drivers/pci/host/pci-mvebu.c @@ -1054,8 +1054,8 @@ static int mvebu_pcie_parse_port(struct mvebu_pcie *pcie, port->pcie = pcie; if (of_property_read_u32(child, "marvell,pcie-port", &port->port)) { - dev_warn(dev, "ignoring %s, missing pcie-port property\n", - of_node_full_name(child)); + dev_warn(dev, "ignoring %pOF, missing pcie-port property\n", + child); goto skip; } @@ -1106,8 +1106,8 @@ static int mvebu_pcie_parse_port(struct mvebu_pcie *pcie, } if (flags & OF_GPIO_ACTIVE_LOW) { - dev_info(dev, "%s: reset gpio is active low\n", - of_node_full_name(child)); + dev_info(dev, "%pOF: reset gpio is active low\n", + child); gpio_flags = GPIOF_ACTIVE_LOW | GPIOF_OUT_INIT_LOW; } else { diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c index b3722b7709df..7eb9be5ae357 100644 --- a/drivers/pci/host/pci-tegra.c +++ b/drivers/pci/host/pci-tegra.c @@ -1703,8 +1703,7 @@ static int tegra_pcie_get_legacy_regulators(struct tegra_pcie *pcie) pcie->num_supplies = 2; if (pcie->num_supplies == 0) { - dev_err(dev, "device %s not supported in legacy mode\n", - np->full_name); + dev_err(dev, "device %pOF not supported in legacy mode\n", np); return -ENODEV; } diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c index 7c203198b582..74f6a17e4614 100644 --- a/drivers/pci/hotplug/pnv_php.c +++ b/drivers/pci/hotplug/pnv_php.c @@ -163,8 +163,8 @@ static void pnv_php_detach_device_nodes(struct device_node *parent) of_node_put(dn); refcount = kref_read(&dn->kobj.kref); if (refcount != 1) - pr_warn("Invalid refcount %d on <%s>\n", - refcount, of_node_full_name(dn)); + pr_warn("Invalid refcount %d on <%pOF>\n", + refcount, dn); of_detach_node(dn); } diff --git a/drivers/pci/hotplug/rpadlpar_core.c b/drivers/pci/hotplug/rpadlpar_core.c index 3f93a4e79595..a3449d717a99 100644 --- a/drivers/pci/hotplug/rpadlpar_core.c +++ b/drivers/pci/hotplug/rpadlpar_core.c @@ -150,8 +150,8 @@ static void dlpar_pci_add_bus(struct device_node *dn) /* Add EADS device to PHB bus, adding new entry to bus->devices */ dev = of_create_pci_dev(dn, phb->bus, pdn->devfn); if (!dev) { - printk(KERN_ERR "%s: failed to create pci dev for %s\n", - __func__, dn->full_name); + printk(KERN_ERR "%s: failed to create pci dev for %pOF\n", + __func__, dn); return; } diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c index 8d132024f06e..1e29abaaea08 100644 --- a/drivers/pci/hotplug/rpaphp_core.c +++ b/drivers/pci/hotplug/rpaphp_core.c @@ -318,7 +318,7 @@ int rpaphp_add_slot(struct device_node *dn) if (!is_php_dn(dn, &indexes, &names, &types, &power_domains)) return 0; - dbg("Entry %s: dn->full_name=%s\n", __func__, dn->full_name); + dbg("Entry %s: dn=%pOF\n", __func__, dn); /* register PCI devices */ name = (char *) &names[1]; diff --git a/drivers/pci/hotplug/rpaphp_pci.c b/drivers/pci/hotplug/rpaphp_pci.c index ea41ea1d3c00..32aabc533be8 100644 --- a/drivers/pci/hotplug/rpaphp_pci.c +++ b/drivers/pci/hotplug/rpaphp_pci.c @@ -95,7 +95,7 @@ int rpaphp_enable_slot(struct slot *slot) bus = pci_find_bus_by_node(slot->dn); if (!bus) { - err("%s: no pci_bus for dn %s\n", __func__, slot->dn->full_name); + err("%s: no pci_bus for dn %pOF\n", __func__, slot->dn); return -EINVAL; } @@ -125,7 +125,7 @@ int rpaphp_enable_slot(struct slot *slot) if (rpaphp_debug) { struct pci_dev *dev; - dbg("%s: pci_devs of slot[%s]\n", __func__, slot->dn->full_name); + dbg("%s: pci_devs of slot[%pOF]\n", __func__, slot->dn); list_for_each_entry(dev, &bus->devices, bus_list) dbg("\t%s\n", pci_name(dev)); } diff --git a/drivers/pci/hotplug/rpaphp_slot.c b/drivers/pci/hotplug/rpaphp_slot.c index 388c4d8fcdd1..489862360f2c 100644 --- a/drivers/pci/hotplug/rpaphp_slot.c +++ b/drivers/pci/hotplug/rpaphp_slot.c @@ -122,8 +122,8 @@ int rpaphp_register_slot(struct slot *slot) int retval; int slotno = -1; - dbg("%s registering slot:path[%s] index[%x], name[%s] pdomain[%x] type[%d]\n", - __func__, slot->dn->full_name, slot->index, slot->name, + dbg("%s registering slot:path[%pOF] index[%x], name[%s] pdomain[%x] type[%d]\n", + __func__, slot->dn, slot->index, slot->name, slot->power_domain, slot->type); /* should not try to register the same slot twice */ diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 93e7b97765d7..c9cdc8a1d48a 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -556,9 +556,9 @@ static ssize_t devspec_show(struct device *dev, struct pci_dev *pdev = to_pci_dev(dev); struct device_node *np = pci_device_to_OF_node(pdev); - if (np == NULL || np->full_name == NULL) + if (np == NULL) return 0; - return sprintf(buf, "%s", np->full_name); + return sprintf(buf, "%pOF", np); } static DEVICE_ATTR_RO(devspec); #endif diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index af0cc3456dc1..e8e40dea2842 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5363,8 +5363,8 @@ static int of_pci_bus_find_domain_nr(struct device *parent) use_dt_domains = 0; domain = pci_get_new_domain_nr(); } else { - dev_err(parent, "Node %s has inconsistent \"linux,pci-domain\" property in DT\n", - parent->of_node->full_name); + dev_err(parent, "Node %pOF has inconsistent \"linux,pci-domain\" property in DT\n", + parent->of_node); domain = -1; } -- cgit v1.2.3 From 821cdad5c46cae94ce65b9a98614c70a6ff021f8 Mon Sep 17 00:00:00 2001 From: Sinan Kaya Date: Tue, 29 Aug 2017 14:45:45 -0500 Subject: PCI: Wait up to 60 seconds for device to become ready after FLR Sporadic reset issues have been observed with an Intel 750 NVMe drive while assigning the physical function to the guest machine. The sequence of events observed is as follows: - perform a Function Level Reset (FLR) - sleep up to 1000ms total - read ~0 from PCI_COMMAND (CRS completion for config read) - warn that the device didn't return from FLR - touch the device before it's ready - device drops config writes when we restore register settings (there's no mechanism for software to learn about CRS completions for writes) - incomplete register restore leaves device in inconsistent state - device probe fails because device is in inconsistent state After reset, an endpoint may respond to config requests with Configuration Request Retry Status (CRS) to indicate that it is not ready to accept new requests. See PCIe r3.1, sec 2.3.1 and 6.6.2. Increase the timeout value from 1 second to 60 seconds to cover the period where device responds with CRS and also report polling progress. Signed-off-by: Sinan Kaya [bhelgaas: include the mandatory 100ms in the delays we print] Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 52 +++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 37 insertions(+), 15 deletions(-) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 7cb29a223b73..827a9f99a8e5 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3820,27 +3820,49 @@ int pci_wait_for_pending_transaction(struct pci_dev *dev) } EXPORT_SYMBOL(pci_wait_for_pending_transaction); -/* - * We should only need to wait 100ms after FLR, but some devices take longer. - * Wait for up to 1000ms for config space to return something other than -1. - * Intel IGD requires this when an LCD panel is attached. We read the 2nd - * dword because VFs don't implement the 1st dword. - */ static void pci_flr_wait(struct pci_dev *dev) { - int i = 0; + int delay = 1, timeout = 60000; u32 id; - do { - msleep(100); + /* + * Per PCIe r3.1, 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); + + /* + * After 100ms, the device should not silently discard config + * requests, but it may still indicate that it needs more time by + * responding to them with CRS completions. The Root Port will + * generally synthesize ~0 data to complete the read (except when + * CRS SV is enabled and the read was for the Vendor ID; in that + * case it synthesizes 0x0001 data). + * + * Wait for the device to return a non-CRS completion. Read the + * Command register instead of Vendor ID so we don't have to + * contend with the CRS SV value. + */ + pci_read_config_dword(dev, PCI_COMMAND, &id); + while (id == ~0) { + if (delay > timeout) { + dev_warn(&dev->dev, "not ready %dms after FLR; giving up\n", + 100 + delay - 1); + return; + } + + if (delay > 1000) + dev_info(&dev->dev, "not ready %dms after FLR; waiting\n", + 100 + delay - 1); + + msleep(delay); + delay *= 2; pci_read_config_dword(dev, PCI_COMMAND, &id); - } while (i++ < 10 && id == ~0); + } - if (id == ~0) - dev_warn(&dev->dev, "Failed to return from FLR\n"); - else if (i > 1) - dev_info(&dev->dev, "Required additional %dms to return from FLR\n", - (i - 1) * 100); + if (delay > 1000) + dev_info(&dev->dev, "ready %dms after FLR\n", 100 + delay - 1); } /** -- cgit v1.2.3