PCI: rockchip: Register IRQ handlers after device and data are ready

[ Upstream commit 3cf5f7ab ]

An IRQ handler may be called at any time after it is registered, so
anything it relies on must be ready before registration.

rockchip_pcie_subsys_irq_handler() and rockchip_pcie_client_irq_handler()
read registers in the PCIe controller, but we registered them before
turning on clocks to the controller.  If either is called before the clocks
are turned on, the register reads fail and the machine hangs.

Similarly, rockchip_pcie_legacy_int_handler() uses rockchip->irq_domain,
but we installed it before initializing irq_domain.

Register IRQ handlers after their data structures are initialized and
clocks are enabled.

Found by enabling CONFIG_DEBUG_SHIRQ, which calls the IRQ handler when it
is being unregistered.  An error during the probe path might cause this
unregistration and IRQ handler execution before the device or data
structure init has finished.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20210608080409.1729276-1-javierm@redhat.com


Reported-by: Peter Robinson <pbrobinson@gmail.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>