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d7f3d47818
Currently x86 support identity mapping between GSI(IOAPIC pin) and IRQ number, so continous IRQs at low end are statically allocated to IOAPICs at boot time. This design causes trouble to support IOAPIC hotplug. This patch implements basic mechanism to dynamically allocate IRQ on demand for IOAPIC pins by using irqdomain framework. It first adds several fields into struct ioapic to support irqdomain. Then it implements an algorithm to dynamically allocate IRQ number for IOAPIC pins on demand. Currently it supports three types of irqdomain: 1) LEGACY: used to support IOAPIC hosting legacy IRQs and building identity mapping for legacy IRQs. A speical case, we dynamically allocate IRQ number for IOAPIC pin which has GSI number below nr_legacy_irqs() but isn't legacy IRQ. This is for backward compatibility and avoid regression. 2) STRICT: build identity mapping between GSI and IRQ nubmer. 3) DYNAMIC: dynamically allocate IRQ number for IOAPIC pin on demand. Legacy(ISA) IRQs is not managed by irqdomain because there may be multiple pins sharing the same IRQ number and current irqdomain only supports 1:1 mapping between pins and IRQ. Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Grant Likely <grant.likely@linaro.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Link: http://lkml.kernel.org/r/1402302011-23642-24-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
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