From 928bea964827d7824b548c1f8e06eccbbc4d0d7d Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Mon, 22 Jul 2013 14:37:17 -0700 Subject: [PATCH] PCI: Delay enabling bridges until they're needed We currently enable PCI bridges after scanning a bus and assigning resources. This is often done in arch code. This patch changes this so we don't enable a bridge until necessary, i.e., until we enable a PCI device behind the bridge. We do this in the generic pci_enable_device() path, so this also removes the arch-specific code to enable bridges. [bhelgaas: changelog] Signed-off-by: Yinghai Lu Signed-off-by: Bjorn Helgaas --- arch/arm/kernel/bios32.c | 5 ----- arch/m68k/platform/coldfire/pci.c | 1 - arch/mips/pci/pci.c | 1 - arch/sh/drivers/pci/pci.c | 1 - drivers/acpi/pci_root.c | 3 --- drivers/parisc/lba_pci.c | 1 - drivers/pci/bus.c | 19 ------------------- drivers/pci/hotplug/acpiphp_glue.c | 1 - drivers/pci/pci.c | 20 ++++++++++++++++++++ drivers/pci/probe.c | 1 - drivers/pci/setup-bus.c | 10 +++------- drivers/pcmcia/cardbus.c | 1 - include/linux/pci.h | 1 - 13 files changed, 23 insertions(+), 42 deletions(-) diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c index 261fcc826169..88e14d74b6de 100644 --- a/arch/arm/kernel/bios32.c +++ b/arch/arm/kernel/bios32.c @@ -525,11 +525,6 @@ void pci_common_init_dev(struct device *parent, struct hw_pci *hw) * Assign resources. */ pci_bus_assign_resources(bus); - - /* - * Enable bridges - */ - pci_enable_bridges(bus); } /* diff --git a/arch/m68k/platform/coldfire/pci.c b/arch/m68k/platform/coldfire/pci.c index b33f97a13e6d..df9679238b6d 100644 --- a/arch/m68k/platform/coldfire/pci.c +++ b/arch/m68k/platform/coldfire/pci.c @@ -319,7 +319,6 @@ static int __init mcf_pci_init(void) pci_fixup_irqs(pci_common_swizzle, mcf_pci_map_irq); pci_bus_size_bridges(rootbus); pci_bus_assign_resources(rootbus); - pci_enable_bridges(rootbus); return 0; } diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c index 594e60d6a43b..33e7aa52d9c4 100644 --- a/arch/mips/pci/pci.c +++ b/arch/mips/pci/pci.c @@ -113,7 +113,6 @@ static void pcibios_scanbus(struct pci_controller *hose) if (!pci_has_flag(PCI_PROBE_ONLY)) { pci_bus_size_bridges(bus); pci_bus_assign_resources(bus); - pci_enable_bridges(bus); } } } diff --git a/arch/sh/drivers/pci/pci.c b/arch/sh/drivers/pci/pci.c index 102f5d58b037..60ed3e1c4b75 100644 --- a/arch/sh/drivers/pci/pci.c +++ b/arch/sh/drivers/pci/pci.c @@ -69,7 +69,6 @@ static void pcibios_scanbus(struct pci_channel *hose) pci_bus_size_bridges(bus); pci_bus_assign_resources(bus); - pci_enable_bridges(bus); } else { pci_free_resource_list(&resources); } diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 5917839321b8..faa1d29c0261 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -527,9 +527,6 @@ static int acpi_pci_root_add(struct acpi_device *device, if (system_state != SYSTEM_BOOTING) { pcibios_resource_survey_bus(root->bus); pci_assign_unassigned_bus_resources(root->bus); - - /* need to after hot-added ioapic is registered */ - pci_enable_bridges(root->bus); } pci_bus_add_devices(root->bus); diff --git a/drivers/parisc/lba_pci.c b/drivers/parisc/lba_pci.c index 19f6f70c67d3..37e71ff6408d 100644 --- a/drivers/parisc/lba_pci.c +++ b/drivers/parisc/lba_pci.c @@ -1590,7 +1590,6 @@ lba_driver_probe(struct parisc_device *dev) lba_dump_res(&lba_dev->hba.lmmio_space, 2); #endif } - pci_enable_bridges(lba_bus); /* ** Once PCI register ops has walked the bus, access to config diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c index b1ff02ab4f13..fc1b74013743 100644 --- a/drivers/pci/bus.c +++ b/drivers/pci/bus.c @@ -216,24 +216,6 @@ void pci_bus_add_devices(const struct pci_bus *bus) } } -void pci_enable_bridges(struct pci_bus *bus) -{ - struct pci_dev *dev; - int retval; - - list_for_each_entry(dev, &bus->devices, bus_list) { - if (dev->subordinate) { - if (!pci_is_enabled(dev)) { - retval = pci_enable_device(dev); - if (retval) - dev_err(&dev->dev, "Error enabling bridge (%d), continuing\n", retval); - pci_set_master(dev); - } - pci_enable_bridges(dev->subordinate); - } - } -} - /** pci_walk_bus - walk devices on/under bus, calling callback. * @top bus whose devices should be walked * @cb callback to be called for each device found @@ -301,4 +283,3 @@ EXPORT_SYMBOL(pci_bus_put); EXPORT_SYMBOL(pci_bus_alloc_resource); EXPORT_SYMBOL_GPL(pci_bus_add_device); EXPORT_SYMBOL(pci_bus_add_devices); -EXPORT_SYMBOL(pci_enable_bridges); diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index 59df8575a48c..52dee9d31e1c 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -723,7 +723,6 @@ static int __ref enable_device(struct acpiphp_slot *slot) acpiphp_sanitize_bus(bus); acpiphp_set_hpp_values(bus); acpiphp_set_acpi_region(slot); - pci_enable_bridges(bus); list_for_each_entry(dev, &bus->devices, bus_list) { /* Assume that newly added devices are powered on already. */ diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e37fea6e178d..44a1a8a0ad7b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1145,6 +1145,24 @@ int pci_reenable_device(struct pci_dev *dev) return 0; } +static void pci_enable_bridge(struct pci_dev *dev) +{ + int retval; + + if (!dev) + return; + + pci_enable_bridge(dev->bus->self); + + if (pci_is_enabled(dev)) + return; + retval = pci_enable_device(dev); + if (retval) + dev_err(&dev->dev, "Error enabling bridge (%d), continuing\n", + retval); + pci_set_master(dev); +} + static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags) { int err; @@ -1165,6 +1183,8 @@ static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags) if (atomic_inc_return(&dev->enable_cnt) > 1) return 0; /* already enabled */ + pci_enable_bridge(dev->bus->self); + /* only skip sriov related */ for (i = 0; i <= PCI_ROM_RESOURCE; i++) if (dev->resource[i].flags & flags) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 46ada5c098eb..85c114cd91cc 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1979,7 +1979,6 @@ unsigned int __ref pci_rescan_bus(struct pci_bus *bus) max = pci_scan_child_bus(bus); pci_assign_unassigned_bus_resources(bus); - pci_enable_bridges(bus); pci_bus_add_devices(bus); return max; diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 4d9ebb4ce015..8f86be13678f 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -1440,7 +1440,7 @@ again: /* any device complain? */ if (list_empty(&fail_head)) - goto enable_and_dump; + goto dump; if (tried_times >= pci_try_num) { if (enable_local == undefined) @@ -1449,7 +1449,7 @@ again: dev_info(&bus->dev, "Automatically enabled pci realloc, if you have problem, try booting with pci=realloc=off\n"); free_list(&fail_head); - goto enable_and_dump; + goto dump; } dev_printk(KERN_DEBUG, &bus->dev, @@ -1482,10 +1482,7 @@ again: goto again; -enable_and_dump: - /* Depth last, update the hardware. */ - pci_enable_bridges(bus); - +dump: /* dump the resource on buses */ pci_bus_dump_resources(bus); } @@ -1556,7 +1553,6 @@ enable_all: if (retval) dev_err(&bridge->dev, "Error reenabling bridge (%d)\n", retval); pci_set_master(bridge); - pci_enable_bridges(parent); } EXPORT_SYMBOL_GPL(pci_assign_unassigned_bridge_resources); diff --git a/drivers/pcmcia/cardbus.c b/drivers/pcmcia/cardbus.c index 9d3ac998fc1f..b2a98cdbd0d2 100644 --- a/drivers/pcmcia/cardbus.c +++ b/drivers/pcmcia/cardbus.c @@ -91,7 +91,6 @@ int __ref cb_alloc(struct pcmcia_socket *s) if (s->tune_bridge) s->tune_bridge(s, bus); - pci_enable_bridges(bus); pci_bus_add_devices(bus); return 0; diff --git a/include/linux/pci.h b/include/linux/pci.h index 0fd1f1582fa1..8cd1e6f30acd 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1043,7 +1043,6 @@ int __must_check pci_bus_alloc_resource(struct pci_bus *bus, resource_size_t, resource_size_t), void *alignf_data); -void pci_enable_bridges(struct pci_bus *bus); /* Proper probing supporting hot-pluggable devices */ int __must_check __pci_register_driver(struct pci_driver *, struct module *, -- 2.20.1