[Trusty SRU] Add MSI/MSI-X driver for APM PCI bus

[Ike Panhc]

This is the driver to enable MSI function on AppliedMicro X-Gene SOC
which reduces interrupt overhead. For 10G or faster networking, this
function is critical to network performance.

This patch will only affect on APM X-Gene SOC, where pci-xgene* only
loaded according to device tree and the new-added helper in msi_bitmap.c
only called from pci-xgene*

We have tested this patch which reduces 55% cpu utilization about 55%
on full loading gigabit ethernet.

Ike Panhc (1):
  UBUNTU: SAUCE: Add MSI/MSI-X driver for APM PCI bus

 arch/arm64/boot/dts/apm-storm.dtsi  |  92 ++++--
 arch/arm64/include/asm/msi_bitmap.h |  36 +++
 arch/arm64/kernel/Makefile          |   1 +
 arch/arm64/kernel/msi_bitmap.c      | 135 +++++++++
 drivers/pci/host/Kconfig            |   4 +
 drivers/pci/host/Makefile           |   1 +
 drivers/pci/host/pci-xgene-msi.c    | 554 ++++++++++++++++++++++++++++++++++++
 drivers/pci/host/pci-xgene.c        | 291 +++++++++++++++++--
 8 files changed, 1070 insertions(+), 44 deletions(-)
 create mode 100644 arch/arm64/include/asm/msi_bitmap.h
 create mode 100644 arch/arm64/kernel/msi_bitmap.c
 create mode 100644 drivers/pci/host/pci-xgene-msi.c

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1.9.1