irqchip/mbigen: Don't use bus_get_dev_root() to find the parent

bus_get_dev_root() returns sp->dev_root which is set in subsys_register(),
but subsys_register() is not called by platform_bus_init().

Therefor for the platform_bus_type, bus_get_dev_root() always returns NULL.
This makes mbigen_of_create_domain() always return -ENODEV.

Don't try to retrieve the parent via bus_get_dev_root() and
unconditionally hand a NULL pointer to of_platform_device_create() to
fix this.

Fixes: fea087fc291b ("irqchip/mbigen: move to use bus_get_dev_root()")
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240220111429.110666-1-chenjun102@huawei.com

irqchip/mbigen: Unify the error handling in mbigen_of_create_domain()

Dan Carpenter reported that commit fea087fc291b "irqchip/mbigen: move
to use bus_get_dev_root()" leads to the following Smatch static checker
warning:

drivers/irqchip/irq-mbigen.c:258 mbigen_of_create_domain()
error: potentially dereferencing uninitialized 'child'.

It should not cause a problem on real hardware, but better to fix the
warning, let's move the bus_get_dev_root() out of the loop, and unify
the error handling to silence it.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230505090654.12793-1-wangkefeng.wang@huawei.com

irqchip: remove MODULE_LICENSE in non-modules

Since commit 8b41fc4454e ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations
are used to identify modules. As a consequence, uses of the macro
in non-modules will cause modprobe to misidentify their containing
object file as a module when it is not (false positives), and modprobe
might succeed rather than failing with a suitable error message.

So remove it in the files in this commit, none of which can be built as
modules.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-modules@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

irqchip/mbigen: move to use bus_get_dev_root()

Direct access to the struct bus_type dev_root pointer is going away soon
so replace that with a call to bus_get_dev_root() instead, which is what
it is there for.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230313182918.1312597-21-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

platform-msi: Rename functions and clarify comments

It's hard to distinguish what platform_msi_domain_alloc() and
platform_msi_domain_alloc_irqs() are about. Make the distinction more
explicit and add comments which explain the use cases properly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211210221814.228706214@linutronix.de

irqchip/mbigen: Repair non-kernel-doc notation

Fix kernel-doc warnings in irq-mbigen.c:

irq-mbigen.c:29: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* In mbigen vector register
irq-mbigen.c:43: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* offset of clear register in mbigen node
irq-mbigen.c:50: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* offset of interrupt type register

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Jun Ma <majun258@huawei.com>
Cc: Yun Wu <wuyun.wu@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Aditya Srivastava <yashsri421@gmail.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210905033644.15988-1-rdunlap@infradead.org

irqchip/mbigen: Fix compile warning when CONFIG_ACPI is disabled

Fix the following compile warning:

drivers/irqchip/irq-mbigen.c:372:36: warning: ‘mbigen_acpi_match’ defined but not used [-Wunused-const-variable=]
static const struct acpi_device_id mbigen_acpi_match[] = {

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210519050455.1693953-1-yangyingliang@huawei.com

irqchip/hisi: Use the correct HiSilicon copyright

s/Hisilicon/HiSilicon/
It should use capital S, according to
https://www.hisilicon.com/en/terms-of-use.

Signed-off-by: Hao Fang <fanghao11@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1617086780-8521-1-git-send-email-fanghao11@huawei.com

irqchip/mbigen: Free msi_desc on device teardown

Using irq_domain_free_irqs_common() on the irqdomain free path will
leave the MSI descriptor unfreed when platform devices get removed.
Properly free it by MSI domain free function.

Fixes: 9650c60ebfec0 ("irqchip/mbigen: Create irq domain for each mbigen device")
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200408114352.1604-1-yuzenghui@huawei.com

irqchip/mbigen: Set driver .suppress_bind_attrs to avoid remove problems

The following crash can be seen for setting
CONFIG_DEBUG_TEST_DRIVER_REMOVE=y for DT FW (which some people still use):

Hisilicon MBIGEN-V2 60080000.interrupt-controller: Failed to create mbi-gen irqdomain
Hisilicon MBIGEN-V2: probe of 60080000.interrupt-controller failed with error -12

[...]

Unable to handle kernel paging request at virtual address 0000000000005008
Mem abort info:
ESR = 0x96000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=0000041fb9990000
[0000000000005008] pgd=0000000000000000
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 7 PID: 1 Comm: swapper/0 Not tainted 5.5.0-rc6-00002-g3fc42638a506-dirty #1622
Hardware name: Huawei Taishan 2280 /D05, BIOS Hisilicon D05 IT21 Nemo 2.0 RC0 04/18/2018
pstate: 40000085 (nZcv daIf -PAN -UAO)
pc : mbigen_set_type+0x38/0x60
lr : __irq_set_trigger+0x6c/0x188
sp : ffff800014b4b400
x29: ffff800014b4b400 x28: 0000000000000007
x27: 0000000000000000 x26: 0000000000000000
x25: ffff041fd83bd0d4 x24: ffff041fd83bd188
x23: 0000000000000000 x22: ffff80001193ce00
x21: 0000000000000004 x20: 0000000000000000
x19: ffff041fd83bd000 x18: ffffffffffffffff
x17: 0000000000000000 x16: 0000000000000000
x15: ffff8000119098c8 x14: ffff041fb94ec91c
x13: ffff041fb94ec1a1 x12: 0000000000000030
x11: 0101010101010101 x10: 0000000000000040
x9 : 0000000000000000 x8 : ffff041fb98c6680
x7 : ffff800014b4b380 x6 : ffff041fd81636c8
x5 : 0000000000000000 x4 : 000000000000025f
x3 : 0000000000005000 x2 : 0000000000005008
x1 : 0000000000000004 x0 : 0000000080000000
Call trace:
mbigen_set_type+0x38/0x60
__setup_irq+0x744/0x900
request_threaded_irq+0xe0/0x198
pcie_pme_probe+0x98/0x118
pcie_port_probe_service+0x38/0x78
really_probe+0xa0/0x3e0
driver_probe_device+0x58/0x100
__device_attach_driver+0x90/0xb0
bus_for_each_drv+0x64/0xc8
__device_attach+0xd8/0x138
device_initial_probe+0x10/0x18
bus_probe_device+0x90/0x98
device_add+0x4c4/0x770
device_register+0x1c/0x28
pcie_port_device_register+0x1e4/0x4f0
pcie_portdrv_probe+0x34/0xd8
local_pci_probe+0x3c/0xa0
pci_device_probe+0x128/0x1c0
really_probe+0xa0/0x3e0
driver_probe_device+0x58/0x100
__device_attach_driver+0x90/0xb0
bus_for_each_drv+0x64/0xc8
__device_attach+0xd8/0x138
device_attach+0x10/0x18
pci_bus_add_device+0x4c/0xb8
pci_bus_add_devices+0x38/0x88
pci_host_probe+0x3c/0xc0
pci_host_common_probe+0xf0/0x208
hisi_pcie_almost_ecam_probe+0x24/0x30
platform_drv_probe+0x50/0xa0
really_probe+0xa0/0x3e0
driver_probe_device+0x58/0x100
device_driver_attach+0x6c/0x90
__driver_attach+0x84/0xc8
bus_for_each_dev+0x74/0xc8
driver_attach+0x20/0x28
bus_add_driver+0x148/0x1f0
driver_register+0x60/0x110
__platform_driver_register+0x40/0x48
hisi_pcie_almost_ecam_driver_init+0x1c/0x24

The specific problem here is that the mbigen driver real probe has failed
as the mbigen_of_create_domain()->of_platform_device_create() call fails,
the reason for that being that we never destroyed the platform device
created during the remove test dry run and there is some conflict.

Since we generally would never want to unbind this driver, and to save
adding a driver tear down path for that, just set the driver
.suppress_bind_attrs member to avoid this possibility.

Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/1579196323-180137-1-git-send-email-john.garry@huawei.com

irqchip/irq-mbigen: Add of_node_put() before return

Each iteration of for_each_child_of_node puts the previous node, but
in the case of a return from the middle of the loop, there is no put,
thus causing a memory leak. Add an of_node_put before the return in
three places.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234

Based on 1 normalized pattern(s):

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 program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

irqchip/mbigen: Stop printing kernel addresses

After commit ad67b74d2469d9b8 ("printk: hash addresses printed with %p"),
it will print "____ptrval____" instead of actual addresses when mbigen
create domain fails,

Hisilicon MBIGEN-V2 HISI0152:00: Failed to create mbi-gen@(____ptrval____) irqdomain
Hisilicon MBIGEN-V2: probe of HISI0152:00 failed with error -12

dev_xxx() helper contains the device info, HISI0152:00, which stands for
mbigen ACPI HID and its UID, we can identify the failing probed mbigen,
so just remove the printing "mgn_chip->base", and also add missing "\n".

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

irqchip/mbigen: Don't clear eventid when freeing an MSI

mbigen_write_msg clears eventid bits of a mbigen register
when free a interrupt, because msi_domain_deactivate memset
struct msg to zero. Then multiple mbigen pins with zero eventid
will report the same interrupt number.

The eventid clear call trace:
free_irq
__free_irq
irq_shutdown
irq_domain_deactivate_irq
__irq_domain_deactivate_irq
__irq_domain_deactivate_irq
msi_domain_deactivate
platform_msi_write_msg
mbigen_write_msg

Signed-off-by: Jianguo Chen <chenjianguo3@huawei.com>
[maz: massaged subject]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

irqchip/irq-mbigen: Constify irq_domain_ops

struct irq_domain_ops is not modified, so it can be made const.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

irqchip/mbigen: Fix the clear register offset calculation

The register array offset for clearing an interrupt is calculated by:

offset = (hwirq - RESERVED_IRQ_PER_MBIGEN_CHIP) / 32;

This is wrong because the clear register array includes the reserved
interrupts. So the clear operation ends up in the wrong register.

This went unnoticed so far, because the hardware clears the real bit
through a timeout mechanism when the hardware is configured in debug
mode. That debug mode was enabled on early generations of the hardware, so
the problem was papered over.

On newer hardware with updated firmware the debug mode was disabled, so the
bits did not get cleared which causes the system to malfunction.

Remove the subtraction of RESERVED_IRQ_PER_MBIGEN_CHIP, so the correct
register is accessed.

[ tglx: Rewrote changelog ]

Fixes: a6c2f87b8820 ("irqchip/mbigen: Implement the mbigen irq chip operation functions")
Signed-off-by: MaJun <majun258@huawei.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: linuxarm@huawei.com
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Link: http://lkml.kernel.org/r/1494561328-39514-4-git-send-email-guohanjun@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

irqchip/mbigen: Fix potential NULL dereferencing

platform_get_resource() may return NULL, add proper
check to avoid potential NULL dereferencing.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: linuxarm@huawei.com
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: MaJun <majun258@huawei.com>
Link: http://lkml.kernel.org/r/1494561328-39514-3-git-send-email-guohanjun@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

irqchip/mbigen: Fix memory mapping code

Some mbigens share memory regions, and devm_ioremap_resource
does not allow to share resources which will break the probe
of mbigen, in opposition to devm_ioremap.

This patch restores back usage of devm_ioremap function, but
with proper error handling and logging.

Fixes: 216646e4d82e ("irqchip/mbigen: Fix return value check in mbigen_device_probe()")
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: linuxarm@huawei.com
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: MaJun <majun258@huawei.com>
Link: http://lkml.kernel.org/r/1494561328-39514-2-git-send-email-guohanjun@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

irqchip/mbigen: Fix return value check in mbigen_device_probe()

In case of error, the function devm_ioremap() returns NULL pointer
not ERR_PTR(). Use devm_ioremap_resource() instead of devm_ioremap()
to fix the IS_ERR() test issue.

Fixes: 76e1f77f9c26 ("irqchip/mbigen: Introduce mbigen_of_create_domain()")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/20170427152113.31147-1-weiyj.lk@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

irqchip/mbigen: Add ACPI support

With the preparation of platform msi support and interrupt producer
in commit d44fa3d46079 ("ACPI: Add support for ResourceSource/IRQ
domain mapping"), we can add mbigen ACPI support now.

Now that the major framework changes are ready, we just need to add
the ACPI probe code which creates the irqdomain for devices connecting
to it.

In order to create the irqdomain, we need to know the number of hw
irqs as input which is provided by mbigen. In DT case, we are using
"num-pins" property to describe it, and we will take advantage of
that too using _DSD in ACPI as there is no standard way of describe
it in ACPI way, also according to the _DSD rule described in
Documentation/acpi/DSD-properties-rules.txt, it doesn't break
the rules.

The DSDT is represented as below:

For mbigen,
Device(MBI0) {
Name(_HID, "HISI0152")
Name(_UID, Zero)
Name(_CRS, ResourceTemplate() {
Memory32Fixed(ReadWrite, 0xa0080000, 0x10000)
})

Name(_DSD, Package () {
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package () {
Package () {"num-pins", 378}
}
})
}

For devices,
Device(SAS0) {
Name(_HID, "HISIxxxx")
Name(_UID, Zero)
Name(_CRS, ResourceTemplate() {
Memory32Fixed(ReadWrite, 0xb0030000, 0x10000)
Interrupt(ResourceConsumer,..., "\_SB.MBI0") {12, ...}
})
}

So for the devices connected to the mbigen, as we clearly say that
it refers to a specific interrupt controller (mbigen), we can get
the virq from mbigen's irqdomain once it's created successfully.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: MaJun <majun258@huawei.com>
Cc: Al Stone <ahs3@redhat.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

irqchip/mbigen: Introduce mbigen_of_create_domain()

Introduce mbigen_of_create_domain() to consolidate OF related
code and prepare for ACPI later, no funtional change.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Ma Jun <majun258@huawei.com>
Tested-by: Ming Lei <ming.lei@canonical.com>
Tested-by: Wei Xu <xuwei5@hisilicon.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

irqchip/mbigen: Drop module owner

Module owner will be set by driver core, so drop it.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Ma Jun <majun258@huawei.com>
Tested-by: Ming Lei <ming.lei@canonical.com>
Tested-by: Wei Xu <xuwei5@hisilicon.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

irqchip/mbigen: Checking for IS_ERR() instead of NULL

of_platform_device_create() returns NULL on error, it never returns
error pointers.

Fixes: ed2a1002d25c ('irqchip/mbigen: Handle multiple device nodes in a mbigen module')
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

irqchip/mbigen: Handle multiple device nodes in a mbigen module

Each mbigen device is represented as a independent platform device. If the
devices belong to the same mbigen hardware module, then the register space for
these devices is the same. That leads to a resource conflict.

The solution for this is to represent the mbigen module as a platform device
and make the mbigen devices subdevices of that. The register space is
associated to the mbigen module and therefor the resource conflict is avoided.

[ tglx: Massaged changelog, cleaned up the code and removed the silly printk ]

Signed-off-by: Ma Jun <majun258@huawei.com>
Cc: mark.rutland@arm.com
Cc: jason@lakedaemon.net
Cc: marc.zyngier@arm.com
Cc: Catalin.Marinas@arm.com
Cc: guohanjun@huawei.com
Cc: Will.Deacon@arm.com
Cc: huxinwei@huawei.com
Cc: lizefan@huawei.com
Cc: dingtianhong@huawei.com
Cc: zhaojunhua@hisilicon.com
Cc: liguozhu@hisilicon.com
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1458203641-17172-3-git-send-email-majun258@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

irqchip/mbigen: Implement the mbigen irq chip operation functions

Add the interrupt controller chip operation functions of mbigen chip.

Signed-off-by: Ma Jun <majun258@huawei.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

irqchip/mbigen: Create irq domain for each mbigen device

For peripheral devices which connect to mbigen,mbigen is a interrupt
controller. So, we create irq domain for each mbigen device and add
mbigen irq domain into irq hierarchy structure.

Signed-off-by: Ma Jun <majun258@huawei.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

irqchip/mgigen: Add platform device driver for mbigen device

Mbigen means Message Based Interrupt Generator(MBIGEN).

Its a kind of interrupt controller that collects
the interrupts from external devices and generate msi interrupt.
Mbigen is applied to reduce the number of wire connected interrupts.

As the peripherals increasing, the interrupts lines needed is
increasing much, especially on the Arm64 server SOC.

Therefore, the interrupt pin in GIC is not enough to cover so
many peripherals.

Mbigen is designed to fix this problem.

Mbigen chip locates in ITS or outside of ITS.

Mbigen chip hardware structure shows as below:

mbigen chip
|---------------------|-------------------|
mgn_node0 mgn_node1 mgn_node2
| |-------| |-------|------|
dev1 dev1 dev2 dev1 dev3 dev4

Each mbigen chip contains several mbigen nodes.

External devices can connect to mbigen node through wire connecting way.

Because a mbigen node only can support 128 interrupt maximum, depends
on the interrupt lines number of devices, a device can connects to one
more mbigen nodes.

Also, several different devices can connect to a same mbigen node.

When devices triggered interrupt,mbigen chip detects and collects
the interrupts and generates the MBI interrupts by writing the ITS
Translator register.

To simplify mbigen driver,I used a new conception--mbigen device.
Each mbigen device is initialized as a platform device.

Mbigen device presents the parts(register, pin definition etc.) in
mbigen chip corresponding to a peripheral device.

So from software view, the structure likes below

mbigen chip
|---------------------|-----------------|
mbigen device1 mbigen device2 mbigen device3
| | |
dev1 dev2 dev3

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ma Jun <majun258@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>