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/loongson-htpic: Fix build warnings

Fix build warnings as below:

drivers/irqchip/irq-loongson-htpic.c: In function 'htpic_reg_init':
>> drivers/irqchip/irq-loongson-htpic.c:62:12: warning: variable 'val' set but not used [-Wunused-but-set-variable]
62 | uint32_t val;
| ^~~
drivers/irqchip/irq-loongson-htpic.c: At top level:
>> drivers/irqchip/irq-loongson-htpic.c:84:12: warning: no previous prototype for 'htpic_of_init' [-Wmissing-prototypes]
84 | int __init htpic_of_init(struct device_node *node, struct device_node *parent)
| ^~~~~~~~~~~~~

Fixes: a93f1d903fa34fc2c5d9fa450bd ("irqchip: Add driver for Loongson-3 HyperTransport PIC controller")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1607159744-995-1-git-send-email-chenhuacai@kernel.org

irqchip/loongson-htpic: Remove redundant kfree operation

In the function htpic_of_init(), when kzalloc htpic fails, it should
return -ENOMEM directly, no need to execute "goto" to kfree.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1594087972-21715-2-git-send-email-yangtiezhu@loongson.cn

irqchip: Add driver for Loongson-3 HyperTransport PIC controller

This controller appeared on Loongson-3 family of chips to receive
interrupts from PCH PIC.
It is a I8259 with optimized interrupt polling flow. We can poll
interrupt number from HT vector directly but still have to follow
standard I8259 routines to mask, unmask and EOI.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Co-developed-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>