On Thu, Sep 11, 2014 at 04:05:48PM +0800, Jiang Liu wrote: > To support IOAPIC hotplug on x86 and IA64 platforms, OS needs to figure > out global interrupt source number(GSI) and IOAPIC enumeration ID > through ACPI interfaces. So BIOS must implement an ACPI IOAPIC device > with _GSB/_UID or _MAT method to support IOAPIC hotplug. OS also needs > to figure out base physical address to access IOAPIC registers. OS may > get the base physical address through PCI BARs if IOAPIC device is > visible in PCI domain, otherwise OS may get the address by ACPI _CRS > method if IOAPIC device is hidden from PCI domain by BIOS. > > When adding a PCI subtree, we need to add IOAPIC devices before enabling > all other PCI devices because other PCI devices may use the IOAPIC to > allocate PCI interrupts. > > So we plan to reimplement IOAPIC driver as an ACPI instead of PCI driver > due to: > 1) hot-pluggable IOAPIC devices are always visible in ACPI domain, > but may or may not be visible in PCI domain. > 2) we could explicitly control the order between IOAPIC and other PCI > devices. > > We also have another choice to use a PCI driver to manage IOAPIC device > if it's visible in PCI domain and use an ACPI driver if it's only > visible in ACPI domain. But this solution is a little complex. > > It shouldn't cause serious backward compatibility issues because: > 1) IOAPIC hotplug is never supported on x86 yet because it hasn't > implemented the required acpi_register_ioapic() and > acpi_unregister_ioapic(). > 2) Currently only ACPI based IOAPIC hotplug is possible on x86 and > IA64, we don't know other specifications and interfaces to support > IOAPIC hotplug yet. > 3) We will reimplement an ACPI IOAPICtdriver support IOAPIC hotplug. > > This change also helps to get rid of the false alarm on all current > Linux distributions: > [ 6.952497] ioapic: probe of 0000:00:05.4 failed with error -22 > [ 6.959542] ioapic: probe of 0000:80:05.4 failed with error -22 > > Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx> Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> I assume this will be merged with the rest of the series, through a non-PCI tree. > --- > drivers/pci/Kconfig | 7 --- > drivers/pci/Makefile | 2 - > drivers/pci/ioapic.c | 121 -------------------------------------------------- > 3 files changed, 130 deletions(-) > delete mode 100644 drivers/pci/ioapic.c > > diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig > index 893503fa1782..39866d18004e 100644 > --- a/drivers/pci/Kconfig > +++ b/drivers/pci/Kconfig > @@ -104,13 +104,6 @@ config PCI_PASID > > If unsure, say N. > > -config PCI_IOAPIC > - bool "PCI IO-APIC hotplug support" if X86 > - depends on PCI > - depends on ACPI > - depends on X86_IO_APIC > - default !X86 > - > config PCI_LABEL > def_bool y if (DMI || ACPI) > select NLS > diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile > index e04fe2d9df3b..73e4af400a5a 100644 > --- a/drivers/pci/Makefile > +++ b/drivers/pci/Makefile > @@ -13,8 +13,6 @@ obj-$(CONFIG_PCI_QUIRKS) += quirks.o > # Build PCI Express stuff if needed > obj-$(CONFIG_PCIEPORTBUS) += pcie/ > > -obj-$(CONFIG_PCI_IOAPIC) += ioapic.o > - > # Build the PCI Hotplug drivers if we were asked to > obj-$(CONFIG_HOTPLUG_PCI) += hotplug/ > ifdef CONFIG_HOTPLUG_PCI > diff --git a/drivers/pci/ioapic.c b/drivers/pci/ioapic.c > deleted file mode 100644 > index f6219d36227f..000000000000 > --- a/drivers/pci/ioapic.c > +++ /dev/null > @@ -1,121 +0,0 @@ > -/* > - * IOAPIC/IOxAPIC/IOSAPIC driver > - * > - * Copyright (C) 2009 Fujitsu Limited. > - * (c) Copyright 2009 Hewlett-Packard Development Company, L.P. > - * > - * This program is free software; you can redistribute it and/or modify > - * it under the terms of the GNU General Public License version 2 as > - * published by the Free Software Foundation. > - */ > - > -/* > - * This driver manages PCI I/O APICs added by hotplug after boot. We try to > - * claim all I/O APIC PCI devices, but those present at boot were registered > - * when we parsed the ACPI MADT, so we'll fail when we try to re-register > - * them. > - */ > - > -#include <linux/pci.h> > -#include <linux/module.h> > -#include <linux/acpi.h> > -#include <linux/slab.h> > - > -struct ioapic { > - acpi_handle handle; > - u32 gsi_base; > -}; > - > -static int ioapic_probe(struct pci_dev *dev, const struct pci_device_id *ent) > -{ > - acpi_handle handle; > - acpi_status status; > - unsigned long long gsb; > - struct ioapic *ioapic; > - int ret; > - char *type; > - struct resource *res; > - > - handle = ACPI_HANDLE(&dev->dev); > - if (!handle) > - return -EINVAL; > - > - status = acpi_evaluate_integer(handle, "_GSB", NULL, &gsb); > - if (ACPI_FAILURE(status)) > - return -EINVAL; > - > - /* > - * The previous code in acpiphp evaluated _MAT if _GSB failed, but > - * ACPI spec 4.0 sec 6.2.2 requires _GSB for hot-pluggable I/O APICs. > - */ > - > - ioapic = kzalloc(sizeof(*ioapic), GFP_KERNEL); > - if (!ioapic) > - return -ENOMEM; > - > - ioapic->handle = handle; > - ioapic->gsi_base = (u32) gsb; > - > - if (dev->class == PCI_CLASS_SYSTEM_PIC_IOAPIC) > - type = "IOAPIC"; > - else > - type = "IOxAPIC"; > - > - ret = pci_enable_device(dev); > - if (ret < 0) > - goto exit_free; > - > - pci_set_master(dev); > - > - if (pci_request_region(dev, 0, type)) > - goto exit_disable; > - > - res = &dev->resource[0]; > - if (acpi_register_ioapic(ioapic->handle, res->start, ioapic->gsi_base)) > - goto exit_release; > - > - pci_set_drvdata(dev, ioapic); > - dev_info(&dev->dev, "%s at %pR, GSI %u\n", type, res, ioapic->gsi_base); > - return 0; > - > -exit_release: > - pci_release_region(dev, 0); > -exit_disable: > - pci_disable_device(dev); > -exit_free: > - kfree(ioapic); > - return -ENODEV; > -} > - > -static void ioapic_remove(struct pci_dev *dev) > -{ > - struct ioapic *ioapic = pci_get_drvdata(dev); > - > - acpi_unregister_ioapic(ioapic->handle, ioapic->gsi_base); > - pci_release_region(dev, 0); > - pci_disable_device(dev); > - kfree(ioapic); > -} > - > - > -static const struct pci_device_id ioapic_devices[] = { > - { PCI_DEVICE_CLASS(PCI_CLASS_SYSTEM_PIC_IOAPIC, ~0) }, > - { PCI_DEVICE_CLASS(PCI_CLASS_SYSTEM_PIC_IOXAPIC, ~0) }, > - { } > -}; > -MODULE_DEVICE_TABLE(pci, ioapic_devices); > - > -static struct pci_driver ioapic_driver = { > - .name = "ioapic", > - .id_table = ioapic_devices, > - .probe = ioapic_probe, > - .remove = ioapic_remove, > -}; > - > -static int __init ioapic_init(void) > -{ > - return pci_register_driver(&ioapic_driver); > -} > -module_init(ioapic_init); > - > -MODULE_LICENSE("GPL"); > -- > 1.7.10.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html