irqchip/realtek-rtl: use parent interrupts

The interrupt-map property for "realtek,rtl-intc" has been deprecated in
favor of a list of parent interrupts. Drop the open-coded parser for
interrupt-map, and use the first parent interrupt instead. If no parent
was provided, the driver will assume that this is the first hardware
interrupt of the SoC's MIPS CPU for compatibility with the legacy binding.

All SoC interrupts were treated equally, independent of which output
they were actually routed to. This means the driver might as well route
all interrupts to the first output, and achieve the same behaviour.

Without the interrupt-map property, interrupt usage information is no
longer available at initialisation. Routing setup will now happen later,
when a hardware interrupt is mapped by the subsystem.

Signed-off-by: Sander Vanheule <sander@svanheule.net>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/5f901a82eaa9d97cadf6e9b73a894a92f3f83b7c.1663617425.git.sander@svanheule.net

irqchip/realtek-rtl: use irq_domain_add_linear()

When using an offset of 0, irq_domain_add_simple() is identical to
irq_domain_add_linear() on DT-based systems, so use the latter instead.

Signed-off-by: Sander Vanheule <sander@svanheule.net>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/0c4cd9f7661a30a4cb7ab9881c4a94bc8a379162.1663617425.git.sander@svanheule.net

irqchip/realtek-rtl: Fix refcount leak in map_interrupts

of_find_node_by_phandle() returns a node pointer with refcount
incremented, we should use of_node_put() on it when not need anymore.
This function doesn't call of_node_put() in error path.
Call of_node_put() directly after of_property_read_u32() to cover
both normal path and error path.

Fixes: 9f3a0f34b84a ("irqchip: Add support for Realtek RTL838x/RTL839x interrupt controller")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220601080930.31005-7-linmq006@gmail.com

irqchip/realtek-rtl: Service all pending interrupts

Instead of only servicing the lowest pending interrupt line, make sure
all pending SoC interrupts are serviced before exiting the chained
handler. This adds a small overhead if only one interrupt is pending,
but should prevent rapid re-triggering of the handler.

Signed-off-by: Sander Vanheule <sander@svanheule.net>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/5082ad3cb8b4eedf55075561b93eff6570299fe1.1641739718.git.sander@svanheule.net

irqchip/realtek-rtl: Fix off-by-one in routing

There is an offset between routing values (1..6) and the connected MIPS
CPU interrupts (2..7), but no distinction was made between these two
values.

This issue was previously hidden during testing, because an interrupt
mapping was used where for each required interrupt another (unused)
routing was configured, with an offset of +1.

Offset the CPU IRQ numbers by -1 to retrieve the correct routing value.

Fixes: 9f3a0f34b84a ("irqchip: Add support for Realtek RTL838x/RTL839x interrupt controller")
Signed-off-by: Sander Vanheule <sander@svanheule.net>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/177b920aa8d8610615692d0e657e509f363c85ca.1641739718.git.sander@svanheule.net

irqchip/realtek-rtl: Map control data to virq

The driver assigned the irqchip and irq handler to the hardware irq,
instead of the virq. This is incorrect, and only worked because these
irq numbers happened to be the same on the devices used for testing the
original driver.

Fixes: 9f3a0f34b84a ("irqchip: Add support for Realtek RTL838x/RTL839x interrupt controller")
Signed-off-by: Sander Vanheule <sander@svanheule.net>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/4b4936606480265db47df152f00bc2ed46340599.1641739718.git.sander@svanheule.net

irqchip: Bulk conversion to generic_handle_domain_irq()

Wherever possible, replace constructs that match either
generic_handle_irq(irq_find_mapping()) or
generic_handle_irq(irq_linear_revmap()) to a single call to
generic_handle_domain_irq().

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

irqchip: Add support for Realtek RTL838x/RTL839x interrupt controller

This is a standard IRQ driver with only status and mask registers.

The mapping from SoC interrupts (18-31) to MIPS core interrupts is
done via an interrupt-map in device tree.

Signed-off-by: Bert Vermeulen <bert@biot.com>
Signed-off-by: Birger Koblitz <mail@birger-koblitz.de>
Acked-by: John Crispin <john@phrozen.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210122204224.509124-3-bert@biot.com