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Legacy PCI host controllers (ie host controllers that set-up the PCI bus through the ARM pci_common_init() API) are currently relying on pci_fixup_irqs() to assign legacy PCI irqs to devices. This is not ideal in that pci_fixup_irqs() assigns IRQs for all PCI devices present in a given system some of which may well be enabled by the time pci_fixup_irqs() is called (ie a system with multiple host controllers). With the introduction of struct pci_host_bridge.(*map_irq) pointer it is possible to assign IRQs for all devices originating from a PCI host bridge at probe time; this is implemented through pci_assign_irq() that relies on the struct pci_host_bridge.map_irq pointer to map IRQ for a given device. The benefits this brings are twofold: - the IRQ for a device is assigned once at probe time - the IRQ assignment works also for hotplugged devices Remove pci_fixup_irqs() call from bios32 code and rely on pci_assign_irq() to carry out the IRQ mapping at device probe time. The map_irq() and swizzle_irq() struct pci_host_bridge callbacks are set-up in the struct pci_host_bridge created in the bios32 pcibios_init_hw() function and mach-* code paths (for PCI mach implementations that require a specific struct hw_pci.(*scan) function callback). Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> [bhelgaas: folded in fixes from Lorenzo: http://lkml.kernel.org/r/20170701140629.GC8977@red-moon] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Russell King <linux@armlinux.org.uk> Cc: Andrew Lunn <andrew@lunn.ch>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.