irqchip/loongson-eiointc: fix gsi register error

upstream: no

When we boot a 3C5000-7A2000 2Node server using "nr_cpus=1 maxcpus=1",
we get the following Call Trace:
    4.807397] ------------[ cut here ]------------
[    4.811996] WARNING: CPU: 0 PID: 1 at drivers/acpi/irq.c:63 acpi_register_gsi+0xe0/0x100
[    4.820048] Modules linked in:
[    4.823082] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.9.0-rc7-next-20240509+ #26
[    4.830604] Hardware name: LOONGSON Dabieshan/Loongson-LS2C50C2, BIOS Loongson UEFI (3C50007A2000_Ls2c5lc2) V4.0.13-Dual 12/06/23 17:33:54
[    4.842964] pc 9000000000bdc6e0 ra 9000000000bdc66c tp 90000002051d4000 sp 90000002051d7ae0
[    4.851269] a0 0000000000000000 a1 00000000000000a0 a2 0000000000000000 a3 0000000000000000
[    4.859567] a4 9000000200014518 a5 000000000000003c a6 90000000018876b0 a7 00302e39303a3030
[    4.867866] t0 0000000000000000 t1 0000000000000080 t2 0000000000000040 t3 0000000000036800
[    4.876165] t4 0000000000036800 t5 0000000000000004 t6 0000000000000000 t7 0000000000000000
[    4.884464] t8 900000000800d910 u0 0000000000000000 s9 90000000014bf9e8 s0 00000000000000a0
[    4.892763] s1 0000000000000000 s2 0000000000000000 s3 9000000001985000 s4 90000002051d7b88
[    4.901063] s5 0000000000000001 s6 90000002055470b8 s7 90000000014400ac s8 0000000000000008
[    4.909362]    ra: 9000000000bdc66c acpi_register_gsi+0x6c/0x100
[    4.915330]   ERA: 9000000000bdc6e0 acpi_register_gsi+0xe0/0x100
[    4.921297]  CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
[    4.927446]  PRMD: 00000004 (PPLV0 +PIE -PWE)
[    4.931777]  EUEN: 00000000 (-FPE -SXE -ASXE -BTE)
[    4.936538]  ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
[    4.941301] ESTAT: 000c0000 [BRK] (IS= ECode=12 EsubCode=0)
[    4.946838]  PRID: 0014c011 (Loongson-64bit, Loongson-3C5000)
[    4.952545] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.9.0-rc7-next-20240509+ #26
[    4.960066] Hardware name: LOONGSON Dabieshan/Loongson-LS2C50C2, BIOS Loongson UEFI (3C50007A2000_Ls2c5lc2) V4.0.13-Dual 12/06/23 17:33:54
[    4.972425] Stack : 9000000001985000 0000000000000000 9000000000223524 90000002051d4000
[    4.980382]         90000002051d7740 90000002051d7748 0000000000000000 90000002051d7888
[    4.988338]         90000002051d7880 90000002051d7880 90000002051d7690 0000000000000001
[    4.996294]         0000000000000001 90000002051d7748 420a070366b7e75d 90000002054f4500
[    5.004251]         0000000000000001 0000000000000000 4137303030354333 c0000000ffffdfff
[    5.012206]         0000000000000003 00000000000ea642 0000000006b3c000 90000000014bf9e8
[    5.020163]         0000000000000000 0000000000000000 90000000017f7e80 9000000001985000
[    5.028119]         0000000000000001 0000000000000000 ffffffffffd7f549 90000000014400ac
[    5.036075]         0000000000000008 0000000000000000 900000000022353c 00007ffff1354000
[    5.044031]         00000000000000b0 0000000000000004 0000000000000000 0000000000071c1d
[    5.051987]         ...
[    5.054410] Call Trace:
[    5.054412] [<900000000022353c>] show_stack+0x5c/0x1a0
[    5.061940] [<900000000141e86c>] dump_stack_lvl+0x9c/0xc4
[    5.067305] [<900000000140170c>] __warn+0x94/0xcc
[    5.071977] [<90000000013cd900>] report_bug+0x160/0x220
[    5.077170] [<900000000141facc>] do_bp+0x26c/0x2e0
[    5.081929] [<0000000000000000>] 0x0
[    5.085475] [<9000000000bdc6e0>] acpi_register_gsi+0xe0/0x100
[    5.091182] [<9000000000bd5350>] acpi_pci_irq_enable+0xd0/0x220
[    5.097061] [<9000000000b5e8d4>] pci_device_probe+0x54/0x260
[    5.102683] [<9000000000d1fefc>] really_probe+0xbc/0x320
[    5.107960] [<9000000000d201f0>] __driver_probe_device+0x90/0x160
[    5.114012] [<9000000000d202f8>] driver_probe_device+0x38/0x120
[    5.119892] [<9000000000d205d4>] __driver_attach+0x94/0x1c0
[    5.125426] [<9000000000d1d7ac>] bus_for_each_dev+0x8c/0x100
[    5.131046] [<9000000000d1ee30>] bus_add_driver+0xf0/0x240
[    5.136494] [<9000000000d21688>] driver_register+0x68/0x140
[    5.142028] [<9000000000220158>] do_one_initcall+0x78/0x200
[    5.147561] [<9000000001440fcc>] kernel_init_freeable+0x23c/0x2b0
[    5.153614] [<900000000142123c>] kernel_init+0x1c/0x120
[    5.158802] [<9000000000221348>] ret_from_kernel_thread+0xc/0xa4

[    5.166244] ---[ end trace 0000000000000000 ]---
[    5.170998] GSI: No registered irqchip, giving up

The root cause is that when the CPU boot from flat mode, it is
unreliable to use cpu_to node to calculate the node number.
Therefore, we use NODES_PER_FLATMODE_NODE to calculate the
physical node number.

According to the 3C5000 user manual, the value of
NODES_PER_FLATMODE_NODE should be 4.

Cc: <stable@vger.kernel.org>
Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>
Signed-off-by: Ming Wang <wangming01@loongson.cn>

arch/loongarch/include/asm/numa.h

@@ -12,6 +12,7 @@
 #include <linux/nodemask.h>
 
 #define NODE_ADDRSPACE_SHIFT 44
+#define NODES_PER_FLATMODE_NODE 4
 
 #define pa_to_nid(addr)		(((addr) & 0xf00000000000) >> NODE_ADDRSPACE_SHIFT)
 #define nid_to_addrbase(nid)	(_ULCAST_(nid) << NODE_ADDRSPACE_SHIFT)

drivers/irqchip/irq-loongson-eiointc.c

@@ -375,7 +375,7 @@ int __init pch_msi_parse_madt(union acpi_subtable_headers *header,
 	int node;
 
 	if (cpu_has_flatmode)
-		node = cpu_to_node(eiointc_priv[nr_pics - 1]->node * CORES_PER_EIO_NODE);
+		node = eiointc_priv[nr_pics - 1]->node / NODES_PER_FLATMODE_NODE;
 	else
 		node = eiointc_priv[nr_pics - 1]->node;
 
@@ -478,7 +478,7 @@ int __init eiointc_acpi_init(struct irq_domain *parent,
 		goto out_free_handle;
 
 	if (cpu_has_flatmode)
-		node = cpu_to_node(acpi_eiointc->node * CORES_PER_EIO_NODE);
+		node = acpi_eiointc->node / NODES_PER_FLATMODE_NODE;
 	else
 		node = acpi_eiointc->node;
 	acpi_set_vec_parent(node, priv->eiointc_domain, pch_group);