LoongArch: Use ACPI_GENERIC_GSI for gsi handling

For LoongArch, generic gsi code(driver/acpi/irq.c) can be
reused after following patchs:

APCI: irq: Add support for multiple GSI domains
ACPI: irq: Allow acpi_gsi_to_irq() to have an arch-specific fallback

So, config ACPI_GENERIC_GSI for LoongArch with removing the gsi code
in arch directory.
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1658314292-35346-6-git-send-email-lvjianmin@loongson.cn

arch/loongarch/Kconfig

@@ -2,6 +2,7 @@
 config LOONGARCH
 	bool
 	default y
+	select ACPI_GENERIC_GSI if ACPI
 	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
 	select ARCH_BINFMT_ELF_STATE
 	select ARCH_ENABLE_MEMORY_HOTPLUG

arch/loongarch/kernel/acpi.c

@@ -25,7 +25,6 @@ EXPORT_SYMBOL(acpi_pci_disabled);
 int acpi_strict = 1; /* We have no workarounds on LoongArch */
 int num_processors;
 int disabled_cpus;
-enum acpi_irq_model_id acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
 
 u64 acpi_saved_sp;
 
@@ -33,70 +32,6 @@ u64 acpi_saved_sp;
 
 #define PREFIX			"ACPI: "
 
-int acpi_gsi_to_irq(u32 gsi, unsigned int *irqp)
-{
-	if (irqp != NULL)
-		*irqp = acpi_register_gsi(NULL, gsi, -1, -1);
-	return (*irqp >= 0) ? 0 : -EINVAL;
-}
-EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
-
-int acpi_isa_irq_to_gsi(unsigned int isa_irq, u32 *gsi)
-{
-	if (gsi)
-		*gsi = isa_irq;
-	return 0;
-}
-
-/*
- * success: return IRQ number (>=0)
- * failure: return < 0
- */
-int acpi_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
-{
-	struct irq_fwspec fwspec;
-
-	switch (gsi) {
-	case GSI_MIN_CPU_IRQ ... GSI_MAX_CPU_IRQ:
-		fwspec.fwnode = liointc_domain->fwnode;
-		fwspec.param[0] = gsi - GSI_MIN_CPU_IRQ;
-		fwspec.param_count = 1;
-
-		return irq_create_fwspec_mapping(&fwspec);
-
-	case GSI_MIN_LPC_IRQ ... GSI_MAX_LPC_IRQ:
-		if (!pch_lpc_domain)
-			return -EINVAL;
-
-		fwspec.fwnode = pch_lpc_domain->fwnode;
-		fwspec.param[0] = gsi - GSI_MIN_LPC_IRQ;
-		fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
-		fwspec.param_count = 2;
-
-		return irq_create_fwspec_mapping(&fwspec);
-
-	case GSI_MIN_PCH_IRQ ... GSI_MAX_PCH_IRQ:
-		if (!pch_pic_domain[0])
-			return -EINVAL;
-
-		fwspec.fwnode = pch_pic_domain[0]->fwnode;
-		fwspec.param[0] = gsi - GSI_MIN_PCH_IRQ;
-		fwspec.param[1] = IRQ_TYPE_LEVEL_HIGH;
-		fwspec.param_count = 2;
-
-		return irq_create_fwspec_mapping(&fwspec);
-	}
-
-	return -EINVAL;
-}
-EXPORT_SYMBOL_GPL(acpi_register_gsi);
-
-void acpi_unregister_gsi(u32 gsi)
-{
-
-}
-EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
-
 void __init __iomem * __acpi_map_table(unsigned long phys, unsigned long size)
 {