lib: utils/irqchip/aplic: add MSI mode support with IMSIC parent linking

Add parent_unique_id fields to struct aplic_data for
IMSIC parent linking in MSI mode. Store parent IMSIC unique_id
during FDT parsing of the APLIC node.

Add aplic_is_msi_mode() complementing aplic_is_direct_mode() to
consolidate delivery mode detection. Add APLIC_TARGET_EIID() macro
for packing the EIID field into the TARGET register.

Add parent_unique_id and parent_irq_map fields to struct aplic_data.
parent_unique_id identifies the upstream IMSIC irqchip device resolved
via sbi_irqchip_find_device() during hwirq_setup. parent_irq_map is
a per-source array allocated at cold init time to track the EIID
assigned by the IMSIC for each APLIC source.

Restore aplic_writel_msicfg() and re-introduce MSI address register
programming in aplic_init(), gated on aplic_is_msi_mode(). Set the
DOMAINCFG_DM bit to switch the hardware to MSI delivery mode when
no IDC structures are present.

Add aplic_program_msi_target() to pack hart_index, guest_index, and
EIID into the APLIC_TARGET register. Add aplic_write_msi() as the
sbi_irqchip write_msi callback that extracts EIID and hart_index from
the MSI message and calls aplic_program_msi_target(). Add
aplic_msi_callback() as the MSI receive callback that dispatches to
sbi_irqchip_process_hwirq() on the APLIC chip.

Extend aplic_hwirq_setup() with an MSI path that resolves the parent
IMSIC chip by parent_unique_id, registers an MSI route via
sbi_irqchip_register_msi(), and stores the allocated EIID in
parent_irq_map for the source being configured.

Extend aplic_hwirq_set_affinity() with an MSI path that delegates
affinity reprogramming to the parent IMSIC chip via
sbi_irqchip_set_affinity() using the stored parent_irq_map entry.

Guard warm_init, process_hwirqs, and hwirq_eoi with early returns in
MSI mode as interrupt delivery and acknowledgement are handled by the
IMSIC in that configuration.

Signed-off-by: Oza Pawandeep <pawandeep.oza@oss.qualcomm.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260721214833.687361-3-pawandeep.oza@oss.qualcomm.com
Signed-off-by: Anup Patel <anup@brainfault.org>

include/sbi_utils/irqchip/aplic.h

@@ -36,6 +36,7 @@ struct aplic_data {
 	struct sbi_dlist node;
 	/* Public members */
 	u32 unique_id;
+	u32 parent_unique_id;
 	unsigned long addr;
 	unsigned long size;
 	unsigned long num_idc;