[PATCH v2 15/53] MIPS: SGI-IP27: put a Bedrock hub's boot CPU in slot 0

[Imre Kaloz <kaloz@kernel.org>]

ip27_smp_setup() takes CPU 0 to be the boot CPU. On a Bedrock hub, swap
the boot CPU's sn_cpu_info[] entry, found by nasid and PI_CPU_NUM slice,
into slot 0, and give slot 0 master_nasid. The PROM's virtids run
densely from 0 in board-list order and so match the table's slots.

Signed-off-by: Imre Kaloz <kaloz@kernel.org>
---
 arch/mips/sgi-ip27/ip27-smp.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/mips/sgi-ip27/ip27-smp.c b/arch/mips/sgi-ip27/ip27-smp.c
index 62733e049570..d49766cffd12 100644
--- a/arch/mips/sgi-ip27/ip27-smp.c
+++ b/arch/mips/sgi-ip27/ip27-smp.c
@@ -80,6 +80,15 @@ void cpu_node_probe(void)
 		highest = node_scan_cpus(nasid, highest);
 	}
 
+	/* The boot CPU must be CPU 0 wherever the board list puts it. */
+	for (i = 1; system_is_ip35 && i <= highest; i++) {
+		if (cputonasid(i) == master_nasid &&
+		    cputoslice(i) == LOCAL_HUB_L(PI_CPU_NUM)) {
+			swap(sn_cpu_info[0], sn_cpu_info[i]);
+			break;
+		}
+	}
+
 	printk("Discovered %d cpus on %d nodes\n", highest + 1, num_online_nodes());
 }
 
@@ -168,9 +177,9 @@ static void __init ip27_smp_setup(void)
 	replicate_kernel_text();
 
 	/*
-	 * PROM sets up system, that boot cpu is always first CPU on nasid 0
+	 * The boot CPU is CPU 0, on the node it booted from
 	 */
-	cputonasid(0) = 0;
+	cputonasid(0) = master_nasid;
 	cputoslice(0) = LOCAL_HUB_L(PI_CPU_NUM);
 }
 
-- 
2.47.3