Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

18 files changed, 2434 insertions, 0 deletions

diff --git a/arch/mips/sgi-ip27/Kconfig b/arch/mips/sgi-ip27/Kconfig
new file mode 100644
index 000000000..e5b6cadbe
--- /dev/null
+++ b/arch/mips/sgi-ip27/Kconfig
@@ -0,0 +1,40 @@
+# SPDX-License-Identifier: GPL-2.0
+choice
+	prompt "Node addressing mode"
+	depends on SGI_IP27
+	default SGI_SN_M_MODE
+
+config SGI_SN_M_MODE
+	bool "IP27 M-Mode"
+	help
+	  The nodes of Origin, Onyx, Fuel and Tezro systems can be configured
+	  in either N-Modes which allows for more nodes or M-Mode which allows
+	  for more memory.  Your hardware is almost certainly running in
+	  M-Mode, so choose M-mode here.
+
+config SGI_SN_N_MODE
+	bool "IP27 N-Mode"
+	help
+	  The nodes of Origin, Onyx, Fuel and Tezro systems can be configured
+	  in either N-Modes which allows for more nodes or M-Mode which allows
+	  for more memory.  Your hardware is almost certainly running in
+	  M-Mode, so choose M-mode here.
+
+endchoice
+
+config MAPPED_KERNEL
+	bool "Mapped kernel support"
+	depends on SGI_IP27
+	help
+	  Change the way a Linux kernel is loaded into memory on a MIPS64
+	  machine.  This is required in order to support text replication on
+	  NUMA.  If you need to understand it, read the source code.
+
+config REPLICATE_KTEXT
+	bool "Kernel text replication support"
+	depends on SGI_IP27
+	select MAPPED_KERNEL
+	help
+	  Say Y here to enable replicating the kernel text across multiple
+	  nodes in a NUMA cluster.  This trades memory for speed.
+
diff --git a/arch/mips/sgi-ip27/Makefile b/arch/mips/sgi-ip27/Makefile
new file mode 100644
index 000000000..27c14ede1
--- /dev/null
+++ b/arch/mips/sgi-ip27/Makefile
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the IP27 specific kernel interface routines under Linux.
+#
+
+obj-y	:= ip27-berr.o ip27-irq.o ip27-init.o ip27-klconfig.o \
+	   ip27-klnuma.o ip27-memory.o ip27-nmi.o ip27-reset.o ip27-timer.o \
+	   ip27-hubio.o ip27-xtalk.o
+
+obj-$(CONFIG_EARLY_PRINTK)	+= ip27-console.o
+obj-$(CONFIG_SMP)		+= ip27-smp.o
diff --git a/arch/mips/sgi-ip27/Platform b/arch/mips/sgi-ip27/Platform
new file mode 100644
index 000000000..e734ee6ab
--- /dev/null
+++ b/arch/mips/sgi-ip27/Platform
@@ -0,0 +1,16 @@
+#
+# SGI-IP27 (Origin200/2000)
+#
+# Set the load address to >= 0xc000000000300000 if you want to leave space for
+# symmon, 0xc00000000001c000 for production kernels.  Note that the value must
+# be 16kb aligned or the handling of the current variable will break.
+#
+cflags-$(CONFIG_SGI_IP27)	+= -I$(srctree)/arch/mips/include/asm/mach-ip27
+ifdef CONFIG_MAPPED_KERNEL
+load-$(CONFIG_SGI_IP27)		+= 0xc00000004001c000
+OBJCOPYFLAGS			:= --change-addresses=0x3fffffff80000000
+dataoffset-$(CONFIG_SGI_IP27)	+= 0x01000000
+else
+load-$(CONFIG_SGI_IP27)		+= 0xa80000000001c000
+OBJCOPYFLAGS			:= --change-addresses=0x57ffffff80000000
+endif
diff --git a/arch/mips/sgi-ip27/TODO b/arch/mips/sgi-ip27/TODO
new file mode 100644
index 000000000..160857ff1
--- /dev/null
+++ b/arch/mips/sgi-ip27/TODO
@@ -0,0 +1,19 @@
+1. Need to figure out why PCI writes to the IOC3 hang, and if it is okay
+not to write to the IOC3 ever.
+2. Need to figure out RRB allocation in bridge_startup().
+3. Need to figure out why address swaizzling is needed in inw/outw for
+Qlogic scsi controllers.
+4. Need to integrate ip27-klconfig.c:find_lboard and
+ip27-init.c:find_lbaord_real. DONE
+5. Is it okay to set calias space on all nodes as 0, instead of 8k as
+in irix?
+6. Investigate why things do not work without the setup_test() call
+being invoked on all nodes in ip27-memory.c.
+8. Too many do_page_faults invoked - investigate.
+9. start_thread must turn off UX64 ... and define tlb_refill_debug.
+10. Need a bad pmd table, bad pte table. __bad_pmd_table/__bad_pagetable
+does not agree with pgd_bad/pmd_bad.
+11. All intrs (ip27_do_irq handlers) are targeted at cpu A on the node.
+This might need to change later. Only the timer intr is set up to be
+received on both Cpu A and B. (ip27_do_irq()/bridge_startup())
+13. Cache flushing (specially the SMP version) has to be investigated.
diff --git a/arch/mips/sgi-ip27/ip27-berr.c b/arch/mips/sgi-ip27/ip27-berr.c
new file mode 100644
index 000000000..5a38ae6bd
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-berr.c
@@ -0,0 +1,96 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1994, 1995, 1996, 1999, 2000 by Ralf Baechle
+ * Copyright (C) 1999, 2000 by Silicon Graphics
+ * Copyright (C) 2002  Maciej W. Rozycki
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>	/* for SIGBUS */
+#include <linux/sched.h>	/* schow_regs(), force_sig() */
+#include <linux/sched/debug.h>
+#include <linux/sched/signal.h>
+
+#include <asm/ptrace.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/agent.h>
+#include <asm/sn/arch.h>
+#include <asm/tlbdebug.h>
+#include <asm/traps.h>
+#include <linux/uaccess.h>
+
+static void dump_hub_information(unsigned long errst0, unsigned long errst1)
+{
+	static char *err_type[2][8] = {
+		{ NULL, "Uncached Partial Read PRERR", "DERR", "Read Timeout",
+		  NULL, NULL, NULL, NULL },
+		{ "WERR", "Uncached Partial Write", "PWERR", "Write Timeout",
+		  NULL, NULL, NULL, NULL }
+	};
+	union pi_err_stat0 st0;
+	union pi_err_stat1 st1;
+
+	st0.pi_stat0_word = errst0;
+	st1.pi_stat1_word = errst1;
+
+	if (!st0.pi_stat0_fmt.s0_valid) {
+		pr_info("Hub does not contain valid error information\n");
+		return;
+	}
+
+	pr_info("Hub has valid error information:\n");
+	if (st0.pi_stat0_fmt.s0_ovr_run)
+		pr_info("Overrun is set. Error stack may contain additional "
+		       "information.\n");
+	pr_info("Hub error address is %08lx\n",
+		(unsigned long)st0.pi_stat0_fmt.s0_addr);
+	pr_info("Incoming message command 0x%lx\n",
+		(unsigned long)st0.pi_stat0_fmt.s0_cmd);
+	pr_info("Supplemental field of incoming message is 0x%lx\n",
+		(unsigned long)st0.pi_stat0_fmt.s0_supl);
+	pr_info("T5 Rn (for RRB only) is 0x%lx\n",
+		(unsigned long)st0.pi_stat0_fmt.s0_t5_req);
+	pr_info("Error type is %s\n", err_type[st1.pi_stat1_fmt.s1_rw_rb]
+	       [st0.pi_stat0_fmt.s0_err_type] ? : "invalid");
+}
+
+int ip27_be_handler(struct pt_regs *regs, int is_fixup)
+{
+	unsigned long errst0, errst1;
+	int data = regs->cp0_cause & 4;
+	int cpu = LOCAL_HUB_L(PI_CPU_NUM);
+
+	if (is_fixup)
+		return MIPS_BE_FIXUP;
+
+	printk("Slice %c got %cbe at 0x%lx\n", 'A' + cpu, data ? 'd' : 'i',
+	       regs->cp0_epc);
+	printk("Hub information:\n");
+	printk("ERR_INT_PEND = 0x%06llx\n", LOCAL_HUB_L(PI_ERR_INT_PEND));
+	errst0 = LOCAL_HUB_L(cpu ? PI_ERR_STATUS0_B : PI_ERR_STATUS0_A);
+	errst1 = LOCAL_HUB_L(cpu ? PI_ERR_STATUS1_B : PI_ERR_STATUS1_A);
+	dump_hub_information(errst0, errst1);
+	show_regs(regs);
+	dump_tlb_all();
+	while(1);
+	force_sig(SIGBUS);
+}
+
+void __init ip27_be_init(void)
+{
+	/* XXX Initialize all the Hub & Bridge error handling here.  */
+	int cpu = LOCAL_HUB_L(PI_CPU_NUM);
+	int cpuoff = cpu << 8;
+
+	board_be_handler = ip27_be_handler;
+
+	LOCAL_HUB_S(PI_ERR_INT_PEND,
+		    cpu ? PI_ERR_CLEAR_ALL_B : PI_ERR_CLEAR_ALL_A);
+	LOCAL_HUB_S(PI_ERR_INT_MASK_A + cpuoff, 0);
+	LOCAL_HUB_S(PI_ERR_STACK_ADDR_A + cpuoff, 0);
+	LOCAL_HUB_S(PI_ERR_STACK_SIZE, 0);	/* Disable error stack */
+	LOCAL_HUB_S(PI_SYSAD_ERRCHK_EN, PI_SYSAD_CHECK_ALL);
+}
diff --git a/arch/mips/sgi-ip27/ip27-common.h b/arch/mips/sgi-ip27/ip27-common.h
new file mode 100644
index 000000000..ed008a084
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-common.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __IP27_COMMON_H
+#define __IP27_COMMON_H
+
+extern nasid_t master_nasid;
+
+extern void cpu_node_probe(void);
+extern void hub_rt_clock_event_init(void);
+extern void hub_rtc_init(nasid_t nasid);
+extern void install_cpu_nmi_handler(int slice);
+extern void install_ipi(void);
+extern void ip27_reboot_setup(void);
+extern const struct plat_smp_ops ip27_smp_ops;
+extern unsigned long node_getfirstfree(nasid_t nasid);
+extern void per_cpu_init(void);
+extern void replicate_kernel_text(void);
+extern void setup_replication_mask(void);
+
+#endif /* __IP27_COMMON_H */
diff --git a/arch/mips/sgi-ip27/ip27-console.c b/arch/mips/sgi-ip27/ip27-console.c
new file mode 100644
index 000000000..7737a88c6
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-console.c
@@ -0,0 +1,42 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2001, 2002 Ralf Baechle
+ */
+
+#include <asm/page.h>
+#include <asm/setup.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/agent.h>
+#include <asm/sn/klconfig.h>
+#include <asm/sn/ioc3.h>
+
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+
+#include "ip27-common.h"
+
+#define IOC3_CLK	(22000000 / 3)
+#define IOC3_FLAGS	(0)
+
+static inline struct ioc3_uartregs *console_uart(void)
+{
+	struct ioc3 *ioc3;
+	nasid_t nasid;
+
+	nasid = (master_nasid == INVALID_NASID) ? get_nasid() : master_nasid;
+	ioc3 = (struct ioc3 *)KL_CONFIG_CH_CONS_INFO(nasid)->memory_base;
+
+	return &ioc3->sregs.uarta;
+}
+
+void prom_putchar(char c)
+{
+	struct ioc3_uartregs *uart = console_uart();
+
+	while ((readb(&uart->iu_lsr) & 0x20) == 0)
+		;
+	writeb(c, &uart->iu_thr);
+}
diff --git a/arch/mips/sgi-ip27/ip27-hubio.c b/arch/mips/sgi-ip27/ip27-hubio.c
new file mode 100644
index 000000000..8352eb640
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-hubio.c
@@ -0,0 +1,185 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 1992-1997, 2000-2003 Silicon Graphics, Inc.
+ * Copyright (C) 2004 Christoph Hellwig.
+ *
+ * Support functions for the HUB ASIC - mostly PIO mapping related.
+ */
+
+#include <linux/bitops.h>
+#include <linux/string.h>
+#include <linux/mmzone.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/agent.h>
+#include <asm/sn/io.h>
+#include <asm/xtalk/xtalk.h>
+
+
+static int force_fire_and_forget = 1;
+
+/**
+ * hub_pio_map	-  establish a HUB PIO mapping
+ *
+ * @hub:	hub to perform PIO mapping on
+ * @widget:	widget ID to perform PIO mapping for
+ * @xtalk_addr: xtalk_address that needs to be mapped
+ * @size:	size of the PIO mapping
+ *
+ **/
+unsigned long hub_pio_map(nasid_t nasid, xwidgetnum_t widget,
+			  unsigned long xtalk_addr, size_t size)
+{
+	unsigned i;
+
+	/* use small-window mapping if possible */
+	if ((xtalk_addr % SWIN_SIZE) + size <= SWIN_SIZE)
+		return NODE_SWIN_BASE(nasid, widget) + (xtalk_addr % SWIN_SIZE);
+
+	if ((xtalk_addr % BWIN_SIZE) + size > BWIN_SIZE) {
+		printk(KERN_WARNING "PIO mapping at hub %d widget %d addr 0x%lx"
+				" too big (%ld)\n",
+				nasid, widget, xtalk_addr, size);
+		return 0;
+	}
+
+	xtalk_addr &= ~(BWIN_SIZE-1);
+	for (i = 0; i < HUB_NUM_BIG_WINDOW; i++) {
+		if (test_and_set_bit(i, hub_data(nasid)->h_bigwin_used))
+			continue;
+
+		/*
+		 * The code below does a PIO write to setup an ITTE entry.
+		 *
+		 * We need to prevent other CPUs from seeing our updated
+		 * memory shadow of the ITTE (in the piomap) until the ITTE
+		 * entry is actually set up; otherwise, another CPU might
+		 * attempt a PIO prematurely.
+		 *
+		 * Also, the only way we can know that an entry has been
+		 * received  by the hub and can be used by future PIO reads/
+		 * writes is by reading back the ITTE entry after writing it.
+		 *
+		 * For these two reasons, we PIO read back the ITTE entry
+		 * after we write it.
+		 */
+		IIO_ITTE_PUT(nasid, i, HUB_PIO_MAP_TO_MEM, widget, xtalk_addr);
+		__raw_readq(IIO_ITTE_GET(nasid, i));
+
+		return NODE_BWIN_BASE(nasid, widget) + (xtalk_addr % BWIN_SIZE);
+	}
+
+	printk(KERN_WARNING "unable to establish PIO mapping for at"
+			" hub %d widget %d addr 0x%lx\n",
+			nasid, widget, xtalk_addr);
+	return 0;
+}
+
+
+/*
+ * hub_setup_prb(nasid, prbnum, credits, conveyor)
+ *
+ *	Put a PRB into fire-and-forget mode if conveyor isn't set.  Otherwise,
+ *	put it into conveyor belt mode with the specified number of credits.
+ */
+static void hub_setup_prb(nasid_t nasid, int prbnum, int credits)
+{
+	union iprb_u prb;
+	int prb_offset;
+
+	/*
+	 * Get the current register value.
+	 */
+	prb_offset = IIO_IOPRB(prbnum);
+	prb.iprb_regval = REMOTE_HUB_L(nasid, prb_offset);
+
+	/*
+	 * Clear out some fields.
+	 */
+	prb.iprb_ovflow = 1;
+	prb.iprb_bnakctr = 0;
+	prb.iprb_anakctr = 0;
+
+	/*
+	 * Enable or disable fire-and-forget mode.
+	 */
+	prb.iprb_ff = force_fire_and_forget ? 1 : 0;
+
+	/*
+	 * Set the appropriate number of PIO credits for the widget.
+	 */
+	prb.iprb_xtalkctr = credits;
+
+	/*
+	 * Store the new value to the register.
+	 */
+	REMOTE_HUB_S(nasid, prb_offset, prb.iprb_regval);
+}
+
+/**
+ * hub_set_piomode  -  set pio mode for a given hub
+ *
+ * @nasid:	physical node ID for the hub in question
+ *
+ * Put the hub into either "PIO conveyor belt" mode or "fire-and-forget" mode.
+ * To do this, we have to make absolutely sure that no PIOs are in progress
+ * so we turn off access to all widgets for the duration of the function.
+ *
+ * XXX - This code should really check what kind of widget we're talking
+ * to.	Bridges can only handle three requests, but XG will do more.
+ * How many can crossbow handle to widget 0?  We're assuming 1.
+ *
+ * XXX - There is a bug in the crossbow that link reset PIOs do not
+ * return write responses.  The easiest solution to this problem is to
+ * leave widget 0 (xbow) in fire-and-forget mode at all times.	This
+ * only affects pio's to xbow registers, which should be rare.
+ **/
+static void hub_set_piomode(nasid_t nasid)
+{
+	u64 ii_iowa;
+	union hubii_wcr_u ii_wcr;
+	unsigned i;
+
+	ii_iowa = REMOTE_HUB_L(nasid, IIO_OUTWIDGET_ACCESS);
+	REMOTE_HUB_S(nasid, IIO_OUTWIDGET_ACCESS, 0);
+
+	ii_wcr.wcr_reg_value = REMOTE_HUB_L(nasid, IIO_WCR);
+
+	if (ii_wcr.iwcr_dir_con) {
+		/*
+		 * Assume a bridge here.
+		 */
+		hub_setup_prb(nasid, 0, 3);
+	} else {
+		/*
+		 * Assume a crossbow here.
+		 */
+		hub_setup_prb(nasid, 0, 1);
+	}
+
+	/*
+	 * XXX - Here's where we should take the widget type into
+	 * when account assigning credits.
+	 */
+	for (i = HUB_WIDGET_ID_MIN; i <= HUB_WIDGET_ID_MAX; i++)
+		hub_setup_prb(nasid, i, 3);
+
+	REMOTE_HUB_S(nasid, IIO_OUTWIDGET_ACCESS, ii_iowa);
+}
+
+/*
+ * hub_pio_init	 -  PIO-related hub initialization
+ *
+ * @hub:	hubinfo structure for our hub
+ */
+void hub_pio_init(nasid_t nasid)
+{
+	unsigned i;
+
+	/* initialize big window piomaps for this hub */
+	bitmap_zero(hub_data(nasid)->h_bigwin_used, HUB_NUM_BIG_WINDOW);
+	for (i = 0; i < HUB_NUM_BIG_WINDOW; i++)
+		IIO_ITTE_DISABLE(nasid, i);
+
+	hub_set_piomode(nasid);
+}
diff --git a/arch/mips/sgi-ip27/ip27-init.c b/arch/mips/sgi-ip27/ip27-init.c
new file mode 100644
index 000000000..a4daf8ccd
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-init.c
@@ -0,0 +1,147 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * Copyright (C) 2000 - 2001 by Kanoj Sarcar (kanoj@sgi.com)
+ * Copyright (C) 2000 - 2001 by Silicon Graphics, Inc.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/mm.h>
+#include <linux/export.h>
+#include <linux/cpumask.h>
+#include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/io.h>
+#include <asm/sgialib.h>
+#include <asm/time.h>
+#include <asm/sn/agent.h>
+#include <asm/sn/types.h>
+#include <asm/sn/klconfig.h>
+#include <asm/sn/ioc3.h>
+#include <asm/mipsregs.h>
+#include <asm/sn/gda.h>
+#include <asm/sn/intr.h>
+#include <asm/current.h>
+#include <asm/processor.h>
+#include <asm/mmu_context.h>
+#include <asm/thread_info.h>
+#include <asm/sn/launch.h>
+#include <asm/sn/mapped_kernel.h>
+
+#include "ip27-common.h"
+
+#define CPU_NONE		(cpuid_t)-1
+
+static DECLARE_BITMAP(hub_init_mask, MAX_NUMNODES);
+nasid_t master_nasid = INVALID_NASID;
+
+struct cpuinfo_ip27 sn_cpu_info[NR_CPUS];
+EXPORT_SYMBOL_GPL(sn_cpu_info);
+
+static void per_hub_init(nasid_t nasid)
+{
+	struct hub_data *hub = hub_data(nasid);
+
+	cpumask_set_cpu(smp_processor_id(), &hub->h_cpus);
+
+	if (test_and_set_bit(nasid, hub_init_mask))
+		return;
+	/*
+	 * Set CRB timeout at 5ms, (< PI timeout of 10ms)
+	 */
+	REMOTE_HUB_S(nasid, IIO_ICTP, 0x800);
+	REMOTE_HUB_S(nasid, IIO_ICTO, 0xff);
+
+	hub_rtc_init(nasid);
+
+	if (nasid) {
+		/* copy exception handlers from first node to current node */
+		memcpy((void *)NODE_OFFSET_TO_K0(nasid, 0),
+		       (void *)CKSEG0, 0x200);
+		__flush_cache_all();
+		/* switch to node local exception handlers */
+		REMOTE_HUB_S(nasid, PI_CALIAS_SIZE, PI_CALIAS_SIZE_8K);
+	}
+}
+
+void per_cpu_init(void)
+{
+	int cpu = smp_processor_id();
+	nasid_t nasid = get_nasid();
+
+	clear_c0_status(ST0_IM);
+
+	per_hub_init(nasid);
+
+	pr_info("CPU %d clock is %dMHz.\n", cpu, sn_cpu_info[cpu].p_speed);
+
+	install_ipi();
+
+	/* Install our NMI handler if symmon hasn't installed one. */
+	install_cpu_nmi_handler(cputoslice(cpu));
+
+	enable_percpu_irq(IP27_HUB_PEND0_IRQ, IRQ_TYPE_NONE);
+	enable_percpu_irq(IP27_HUB_PEND1_IRQ, IRQ_TYPE_NONE);
+}
+
+void __init plat_mem_setup(void)
+{
+	u64 p, e, n_mode;
+	nasid_t nid;
+
+	register_smp_ops(&ip27_smp_ops);
+
+	ip27_reboot_setup();
+
+	/*
+	 * hub_rtc init and cpu clock intr enabled for later calibrate_delay.
+	 */
+	nid = get_nasid();
+	printk("IP27: Running on node %d.\n", nid);
+
+	p = LOCAL_HUB_L(PI_CPU_PRESENT_A) & 1;
+	e = LOCAL_HUB_L(PI_CPU_ENABLE_A) & 1;
+	printk("Node %d has %s primary CPU%s.\n", nid,
+	       p ? "a" : "no",
+	       e ? ", CPU is running" : "");
+
+	p = LOCAL_HUB_L(PI_CPU_PRESENT_B) & 1;
+	e = LOCAL_HUB_L(PI_CPU_ENABLE_B) & 1;
+	printk("Node %d has %s secondary CPU%s.\n", nid,
+	       p ? "a" : "no",
+	       e ? ", CPU is running" : "");
+
+	/*
+	 * Try to catch kernel missconfigurations and give user an
+	 * indication what option to select.
+	 */
+	n_mode = LOCAL_HUB_L(NI_STATUS_REV_ID) & NSRI_MORENODES_MASK;
+	printk("Machine is in %c mode.\n", n_mode ? 'N' : 'M');
+#ifdef CONFIG_SGI_SN_N_MODE
+	if (!n_mode)
+		panic("Kernel compiled for M mode.");
+#else
+	if (n_mode)
+		panic("Kernel compiled for N mode.");
+#endif
+
+	ioport_resource.start = 0;
+	ioport_resource.end = ~0UL;
+	set_io_port_base(IO_BASE);
+}
+
+const char *get_system_type(void)
+{
+	return "SGI Origin";
+}
+
+void __init prom_init(void)
+{
+	prom_init_cmdline(fw_arg0, (LONG *)fw_arg1);
+	prom_meminit();
+}
+
diff --git a/arch/mips/sgi-ip27/ip27-irq.c b/arch/mips/sgi-ip27/ip27-irq.c
new file mode 100644
index 000000000..42df9fafa
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-irq.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ip27-irq.c: Highlevel interrupt handling for IP27 architecture.
+ *
+ * Copyright (C) 1999, 2000 Ralf Baechle (ralf@gnu.org)
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 1999 - 2001 Kanoj Sarcar
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/sched.h>
+
+#include <asm/io.h>
+#include <asm/irq_cpu.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/agent.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/intr.h>
+#include <asm/sn/irq_alloc.h>
+
+struct hub_irq_data {
+	u64	*irq_mask[2];
+	cpuid_t	cpu;
+};
+
+static DECLARE_BITMAP(hub_irq_map, IP27_HUB_IRQ_COUNT);
+
+static DEFINE_PER_CPU(unsigned long [2], irq_enable_mask);
+
+static inline int alloc_level(void)
+{
+	int level;
+
+again:
+	level = find_first_zero_bit(hub_irq_map, IP27_HUB_IRQ_COUNT);
+	if (level >= IP27_HUB_IRQ_COUNT)
+		return -ENOSPC;
+
+	if (test_and_set_bit(level, hub_irq_map))
+		goto again;
+
+	return level;
+}
+
+static void enable_hub_irq(struct irq_data *d)
+{
+	struct hub_irq_data *hd = irq_data_get_irq_chip_data(d);
+	unsigned long *mask = per_cpu(irq_enable_mask, hd->cpu);
+
+	set_bit(d->hwirq, mask);
+	__raw_writeq(mask[0], hd->irq_mask[0]);
+	__raw_writeq(mask[1], hd->irq_mask[1]);
+}
+
+static void disable_hub_irq(struct irq_data *d)
+{
+	struct hub_irq_data *hd = irq_data_get_irq_chip_data(d);
+	unsigned long *mask = per_cpu(irq_enable_mask, hd->cpu);
+
+	clear_bit(d->hwirq, mask);
+	__raw_writeq(mask[0], hd->irq_mask[0]);
+	__raw_writeq(mask[1], hd->irq_mask[1]);
+}
+
+static void setup_hub_mask(struct hub_irq_data *hd, const struct cpumask *mask)
+{
+	nasid_t nasid;
+	int cpu;
+
+	cpu = cpumask_first_and(mask, cpu_online_mask);
+	if (cpu >= nr_cpu_ids)
+		cpu = cpumask_any(cpu_online_mask);
+
+	nasid = cpu_to_node(cpu);
+	hd->cpu = cpu;
+	if (!cputoslice(cpu)) {
+		hd->irq_mask[0] = REMOTE_HUB_PTR(nasid, PI_INT_MASK0_A);
+		hd->irq_mask[1] = REMOTE_HUB_PTR(nasid, PI_INT_MASK1_A);
+	} else {
+		hd->irq_mask[0] = REMOTE_HUB_PTR(nasid, PI_INT_MASK0_B);
+		hd->irq_mask[1] = REMOTE_HUB_PTR(nasid, PI_INT_MASK1_B);
+	}
+}
+
+static int set_affinity_hub_irq(struct irq_data *d, const struct cpumask *mask,
+				bool force)
+{
+	struct hub_irq_data *hd = irq_data_get_irq_chip_data(d);
+
+	if (!hd)
+		return -EINVAL;
+
+	if (irqd_is_started(d))
+		disable_hub_irq(d);
+
+	setup_hub_mask(hd, mask);
+
+	if (irqd_is_started(d))
+		enable_hub_irq(d);
+
+	irq_data_update_effective_affinity(d, cpumask_of(hd->cpu));
+
+	return 0;
+}
+
+static struct irq_chip hub_irq_type = {
+	.name		  = "HUB",
+	.irq_mask	  = disable_hub_irq,
+	.irq_unmask	  = enable_hub_irq,
+	.irq_set_affinity = set_affinity_hub_irq,
+};
+
+static int hub_domain_alloc(struct irq_domain *domain, unsigned int virq,
+			    unsigned int nr_irqs, void *arg)
+{
+	struct irq_alloc_info *info = arg;
+	struct hub_irq_data *hd;
+	struct hub_data *hub;
+	struct irq_desc *desc;
+	int swlevel;
+
+	if (nr_irqs > 1 || !info)
+		return -EINVAL;
+
+	hd = kzalloc(sizeof(*hd), GFP_KERNEL);
+	if (!hd)
+		return -ENOMEM;
+
+	swlevel = alloc_level();
+	if (unlikely(swlevel < 0)) {
+		kfree(hd);
+		return -EAGAIN;
+	}
+	irq_domain_set_info(domain, virq, swlevel, &hub_irq_type, hd,
+			    handle_level_irq, NULL, NULL);
+
+	/* use CPU connected to nearest hub */
+	hub = hub_data(info->nasid);
+	setup_hub_mask(hd, &hub->h_cpus);
+	info->nasid = cpu_to_node(hd->cpu);
+
+	/* Make sure it's not already pending when we connect it. */
+	REMOTE_HUB_CLR_INTR(info->nasid, swlevel);
+
+	desc = irq_to_desc(virq);
+	desc->irq_common_data.node = info->nasid;
+	cpumask_copy(desc->irq_common_data.affinity, &hub->h_cpus);
+
+	return 0;
+}
+
+static void hub_domain_free(struct irq_domain *domain,
+			    unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *irqd;
+
+	if (nr_irqs > 1)
+		return;
+
+	irqd = irq_domain_get_irq_data(domain, virq);
+	if (irqd && irqd->chip_data)
+		kfree(irqd->chip_data);
+}
+
+static const struct irq_domain_ops hub_domain_ops = {
+	.alloc = hub_domain_alloc,
+	.free  = hub_domain_free,
+};
+
+/*
+ * This code is unnecessarily complex, because we do
+ * intr enabling. Basically, once we grab the set of intrs we need
+ * to service, we must mask _all_ these interrupts; firstly, to make
+ * sure the same intr does not intr again, causing recursion that
+ * can lead to stack overflow. Secondly, we can not just mask the
+ * one intr we are do_IRQing, because the non-masked intrs in the
+ * first set might intr again, causing multiple servicings of the
+ * same intr. This effect is mostly seen for intercpu intrs.
+ * Kanoj 05.13.00
+ */
+
+static void ip27_do_irq_mask0(struct irq_desc *desc)
+{
+	cpuid_t cpu = smp_processor_id();
+	unsigned long *mask = per_cpu(irq_enable_mask, cpu);
+	struct irq_domain *domain;
+	u64 pend0;
+	int irq;
+
+	/* copied from Irix intpend0() */
+	pend0 = LOCAL_HUB_L(PI_INT_PEND0);
+
+	pend0 &= mask[0];		/* Pick intrs we should look at */
+	if (!pend0)
+		return;
+
+#ifdef CONFIG_SMP
+	if (pend0 & (1UL << CPU_RESCHED_A_IRQ)) {
+		LOCAL_HUB_CLR_INTR(CPU_RESCHED_A_IRQ);
+		scheduler_ipi();
+	} else if (pend0 & (1UL << CPU_RESCHED_B_IRQ)) {
+		LOCAL_HUB_CLR_INTR(CPU_RESCHED_B_IRQ);
+		scheduler_ipi();
+	} else if (pend0 & (1UL << CPU_CALL_A_IRQ)) {
+		LOCAL_HUB_CLR_INTR(CPU_CALL_A_IRQ);
+		generic_smp_call_function_interrupt();
+	} else if (pend0 & (1UL << CPU_CALL_B_IRQ)) {
+		LOCAL_HUB_CLR_INTR(CPU_CALL_B_IRQ);
+		generic_smp_call_function_interrupt();
+	} else
+#endif
+	{
+		domain = irq_desc_get_handler_data(desc);
+		irq = irq_linear_revmap(domain, __ffs(pend0));
+		if (irq)
+			generic_handle_irq(irq);
+		else
+			spurious_interrupt();
+	}
+
+	LOCAL_HUB_L(PI_INT_PEND0);
+}
+
+static void ip27_do_irq_mask1(struct irq_desc *desc)
+{
+	cpuid_t cpu = smp_processor_id();
+	unsigned long *mask = per_cpu(irq_enable_mask, cpu);
+	struct irq_domain *domain;
+	u64 pend1;
+	int irq;
+
+	/* copied from Irix intpend0() */
+	pend1 = LOCAL_HUB_L(PI_INT_PEND1);
+
+	pend1 &= mask[1];		/* Pick intrs we should look at */
+	if (!pend1)
+		return;
+
+	domain = irq_desc_get_handler_data(desc);
+	irq = irq_linear_revmap(domain, __ffs(pend1) + 64);
+	if (irq)
+		generic_handle_irq(irq);
+	else
+		spurious_interrupt();
+
+	LOCAL_HUB_L(PI_INT_PEND1);
+}
+
+void install_ipi(void)
+{
+	int cpu = smp_processor_id();
+	unsigned long *mask = per_cpu(irq_enable_mask, cpu);
+	int slice = LOCAL_HUB_L(PI_CPU_NUM);
+	int resched, call;
+
+	resched = CPU_RESCHED_A_IRQ + slice;
+	set_bit(resched, mask);
+	LOCAL_HUB_CLR_INTR(resched);
+
+	call = CPU_CALL_A_IRQ + slice;
+	set_bit(call, mask);
+	LOCAL_HUB_CLR_INTR(call);
+
+	if (slice == 0) {
+		LOCAL_HUB_S(PI_INT_MASK0_A, mask[0]);
+		LOCAL_HUB_S(PI_INT_MASK1_A, mask[1]);
+	} else {
+		LOCAL_HUB_S(PI_INT_MASK0_B, mask[0]);
+		LOCAL_HUB_S(PI_INT_MASK1_B, mask[1]);
+	}
+}
+
+void __init arch_init_irq(void)
+{
+	struct irq_domain *domain;
+	struct fwnode_handle *fn;
+	int i;
+
+	mips_cpu_irq_init();
+
+	/*
+	 * Some interrupts are reserved by hardware or by software convention.
+	 * Mark these as reserved right away so they won't be used accidentally
+	 * later.
+	 */
+	for (i = 0; i <= CPU_CALL_B_IRQ; i++)
+		set_bit(i, hub_irq_map);
+
+	for (i = NI_BRDCAST_ERR_A; i <= MSC_PANIC_INTR; i++)
+		set_bit(i, hub_irq_map);
+
+	fn = irq_domain_alloc_named_fwnode("HUB");
+	WARN_ON(fn == NULL);
+	if (!fn)
+		return;
+	domain = irq_domain_create_linear(fn, IP27_HUB_IRQ_COUNT,
+					  &hub_domain_ops, NULL);
+	WARN_ON(domain == NULL);
+	if (!domain)
+		return;
+
+	irq_set_default_host(domain);
+
+	irq_set_percpu_devid(IP27_HUB_PEND0_IRQ);
+	irq_set_chained_handler_and_data(IP27_HUB_PEND0_IRQ, ip27_do_irq_mask0,
+					 domain);
+	irq_set_percpu_devid(IP27_HUB_PEND1_IRQ);
+	irq_set_chained_handler_and_data(IP27_HUB_PEND1_IRQ, ip27_do_irq_mask1,
+					 domain);
+}
diff --git a/arch/mips/sgi-ip27/ip27-klconfig.c b/arch/mips/sgi-ip27/ip27-klconfig.c
new file mode 100644
index 000000000..81a1646e6
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-klconfig.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1999, 2000 Ralf Baechle (ralf@gnu.org)
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ */
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/param.h>
+#include <linux/timex.h>
+#include <linux/mm.h>
+
+#include <asm/sn/klconfig.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/gda.h>
+
+klinfo_t *find_component(lboard_t *brd, klinfo_t *kli, unsigned char struct_type)
+{
+	int index, j;
+
+	if (kli == (klinfo_t *)NULL) {
+		index = 0;
+	} else {
+		for (j = 0; j < KLCF_NUM_COMPS(brd); j++)
+			if (kli == KLCF_COMP(brd, j))
+				break;
+		index = j;
+		if (index == KLCF_NUM_COMPS(brd)) {
+			printk("find_component: Bad pointer: 0x%p\n", kli);
+			return (klinfo_t *)NULL;
+		}
+		index++;		/* next component */
+	}
+
+	for (; index < KLCF_NUM_COMPS(brd); index++) {
+		kli = KLCF_COMP(brd, index);
+		if (KLCF_COMP_TYPE(kli) == struct_type)
+			return kli;
+	}
+
+	/* Didn't find it. */
+	return (klinfo_t *)NULL;
+}
+
+klinfo_t *find_first_component(lboard_t *brd, unsigned char struct_type)
+{
+	return find_component(brd, (klinfo_t *)NULL, struct_type);
+}
+
+lboard_t *find_lboard(lboard_t *start, unsigned char brd_type)
+{
+	/* Search all boards stored on this node. */
+	while (start) {
+		if (start->brd_type == brd_type)
+			return start;
+		start = KLCF_NEXT(start);
+	}
+	/* Didn't find it. */
+	return (lboard_t *)NULL;
+}
+
+lboard_t *find_lboard_class(lboard_t *start, unsigned char brd_type)
+{
+	/* Search all boards stored on this node. */
+	while (start) {
+		if (KLCLASS(start->brd_type) == KLCLASS(brd_type))
+			return start;
+		start = KLCF_NEXT(start);
+	}
+
+	/* Didn't find it. */
+	return (lboard_t *)NULL;
+}
diff --git a/arch/mips/sgi-ip27/ip27-klnuma.c b/arch/mips/sgi-ip27/ip27-klnuma.c
new file mode 100644
index 000000000..abd7a84df
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-klnuma.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Ported from IRIX to Linux by Kanoj Sarcar, 06/08/00.
+ * Copyright 2000 - 2001 Silicon Graphics, Inc.
+ * Copyright 2000 - 2001 Kanoj Sarcar (kanoj@sgi.com)
+ */
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/kernel.h>
+#include <linux/nodemask.h>
+#include <linux/string.h>
+
+#include <asm/page.h>
+#include <asm/sections.h>
+#include <asm/sn/types.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/gda.h>
+#include <asm/sn/mapped_kernel.h>
+
+#include "ip27-common.h"
+
+static nodemask_t ktext_repmask;
+
+/*
+ * XXX - This needs to be much smarter about where it puts copies of the
+ * kernel.  For example, we should never put a copy on a headless node,
+ * and we should respect the topology of the machine.
+ */
+void __init setup_replication_mask(void)
+{
+	/* Set only the master cnode's bit.  The master cnode is always 0. */
+	nodes_clear(ktext_repmask);
+	node_set(0, ktext_repmask);
+
+#ifdef CONFIG_REPLICATE_KTEXT
+#ifndef CONFIG_MAPPED_KERNEL
+#error Kernel replication works with mapped kernel support. No calias support.
+#endif
+	{
+		nasid_t nasid;
+
+		for_each_online_node(nasid) {
+			if (nasid == 0)
+				continue;
+			/* Advertise that we have a copy of the kernel */
+			node_set(nasid, ktext_repmask);
+		}
+	}
+#endif
+	/* Set up a GDA pointer to the replication mask. */
+	GDA->g_ktext_repmask = &ktext_repmask;
+}
+
+
+static __init void set_ktext_source(nasid_t client_nasid, nasid_t server_nasid)
+{
+	kern_vars_t *kvp;
+
+	kvp = &hub_data(client_nasid)->kern_vars;
+
+	KERN_VARS_ADDR(client_nasid) = (unsigned long)kvp;
+
+	kvp->kv_magic = KV_MAGIC;
+	kvp->kv_ro_nasid = server_nasid;
+	kvp->kv_rw_nasid = master_nasid;
+	kvp->kv_ro_baseaddr = NODE_CAC_BASE(server_nasid);
+	kvp->kv_rw_baseaddr = NODE_CAC_BASE(master_nasid);
+	printk("REPLICATION: ON nasid %d, ktext from nasid %d, kdata from nasid %d\n", client_nasid, server_nasid, master_nasid);
+}
+
+/* XXX - When the BTE works, we should use it instead of this. */
+static __init void copy_kernel(nasid_t dest_nasid)
+{
+	unsigned long dest_kern_start, source_start, source_end, kern_size;
+
+	source_start = (unsigned long) _stext;
+	source_end = (unsigned long) _etext;
+	kern_size = source_end - source_start;
+
+	dest_kern_start = CHANGE_ADDR_NASID(MAPPED_KERN_RO_TO_K0(source_start),
+					    dest_nasid);
+	memcpy((void *)dest_kern_start, (void *)source_start, kern_size);
+}
+
+void __init replicate_kernel_text(void)
+{
+	nasid_t client_nasid;
+	nasid_t server_nasid;
+
+	server_nasid = master_nasid;
+
+	/* Record where the master node should get its kernel text */
+	set_ktext_source(master_nasid, master_nasid);
+
+	for_each_online_node(client_nasid) {
+		if (client_nasid == 0)
+			continue;
+
+		/* Check if this node should get a copy of the kernel */
+		if (node_isset(client_nasid, ktext_repmask)) {
+			server_nasid = client_nasid;
+			copy_kernel(server_nasid);
+		}
+
+		/* Record where this node should get its kernel text */
+		set_ktext_source(client_nasid, server_nasid);
+	}
+}
+
+/*
+ * Return pfn of first free page of memory on a node. PROM may allocate
+ * data structures on the first couple of pages of the first slot of each
+ * node. If this is the case, getfirstfree(node) > getslotstart(node, 0).
+ */
+unsigned long node_getfirstfree(nasid_t nasid)
+{
+	unsigned long loadbase = REP_BASE;
+	unsigned long offset;
+
+#ifdef CONFIG_MAPPED_KERNEL
+	loadbase += 16777216;
+#endif
+	offset = PAGE_ALIGN((unsigned long)(&_end)) - loadbase;
+	if ((nasid == 0) || (node_isset(nasid, ktext_repmask)))
+		return TO_NODE(nasid, offset) >> PAGE_SHIFT;
+	else
+		return KDM_TO_PHYS(PAGE_ALIGN(SYMMON_STK_ADDR(nasid, 0))) >> PAGE_SHIFT;
+}
diff --git a/arch/mips/sgi-ip27/ip27-memory.c b/arch/mips/sgi-ip27/ip27-memory.c
new file mode 100644
index 000000000..d411e0a90
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-memory.c
@@ -0,0 +1,429 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2000, 05 by Ralf Baechle (ralf@linux-mips.org)
+ * Copyright (C) 2000 by Silicon Graphics, Inc.
+ * Copyright (C) 2004 by Christoph Hellwig
+ *
+ * On SGI IP27 the ARC memory configuration data is completely bogus but
+ * alternate easier to use mechanisms are available.
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/memblock.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/export.h>
+#include <linux/nodemask.h>
+#include <linux/swap.h>
+#include <linux/pfn.h>
+#include <linux/highmem.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/sections.h>
+
+#include <asm/sn/arch.h>
+#include <asm/sn/agent.h>
+#include <asm/sn/klconfig.h>
+
+#include "ip27-common.h"
+
+#define SLOT_PFNSHIFT		(SLOT_SHIFT - PAGE_SHIFT)
+#define PFN_NASIDSHFT		(NASID_SHFT - PAGE_SHIFT)
+
+struct node_data *__node_data[MAX_NUMNODES];
+
+EXPORT_SYMBOL(__node_data);
+
+static u64 gen_region_mask(void)
+{
+	int region_shift;
+	u64 region_mask;
+	nasid_t nasid;
+
+	region_shift = get_region_shift();
+	region_mask = 0;
+	for_each_online_node(nasid)
+		region_mask |= BIT_ULL(nasid >> region_shift);
+
+	return region_mask;
+}
+
+#define rou_rflag	rou_flags
+
+static int router_distance;
+
+static void router_recurse(klrou_t *router_a, klrou_t *router_b, int depth)
+{
+	klrou_t *router;
+	lboard_t *brd;
+	int	port;
+
+	if (router_a->rou_rflag == 1)
+		return;
+
+	if (depth >= router_distance)
+		return;
+
+	router_a->rou_rflag = 1;
+
+	for (port = 1; port <= MAX_ROUTER_PORTS; port++) {
+		if (router_a->rou_port[port].port_nasid == INVALID_NASID)
+			continue;
+
+		brd = (lboard_t *)NODE_OFFSET_TO_K0(
+			router_a->rou_port[port].port_nasid,
+			router_a->rou_port[port].port_offset);
+
+		if (brd->brd_type == KLTYPE_ROUTER) {
+			router = (klrou_t *)NODE_OFFSET_TO_K0(NASID_GET(brd), brd->brd_compts[0]);
+			if (router == router_b) {
+				if (depth < router_distance)
+					router_distance = depth;
+			}
+			else
+				router_recurse(router, router_b, depth + 1);
+		}
+	}
+
+	router_a->rou_rflag = 0;
+}
+
+unsigned char __node_distances[MAX_NUMNODES][MAX_NUMNODES];
+EXPORT_SYMBOL(__node_distances);
+
+static int __init compute_node_distance(nasid_t nasid_a, nasid_t nasid_b)
+{
+	klrou_t *router, *router_a = NULL, *router_b = NULL;
+	lboard_t *brd, *dest_brd;
+	nasid_t nasid;
+	int port;
+
+	/* Figure out which routers nodes in question are connected to */
+	for_each_online_node(nasid) {
+		brd = find_lboard_class((lboard_t *)KL_CONFIG_INFO(nasid),
+					KLTYPE_ROUTER);
+
+		if (!brd)
+			continue;
+
+		do {
+			if (brd->brd_flags & DUPLICATE_BOARD)
+				continue;
+
+			router = (klrou_t *)NODE_OFFSET_TO_K0(NASID_GET(brd), brd->brd_compts[0]);
+			router->rou_rflag = 0;
+
+			for (port = 1; port <= MAX_ROUTER_PORTS; port++) {
+				if (router->rou_port[port].port_nasid == INVALID_NASID)
+					continue;
+
+				dest_brd = (lboard_t *)NODE_OFFSET_TO_K0(
+					router->rou_port[port].port_nasid,
+					router->rou_port[port].port_offset);
+
+				if (dest_brd->brd_type == KLTYPE_IP27) {
+					if (dest_brd->brd_nasid == nasid_a)
+						router_a = router;
+					if (dest_brd->brd_nasid == nasid_b)
+						router_b = router;
+				}
+			}
+
+		} while ((brd = find_lboard_class(KLCF_NEXT(brd), KLTYPE_ROUTER)));
+	}
+
+	if (nasid_a == nasid_b)
+		return LOCAL_DISTANCE;
+
+	if (router_a == router_b)
+		return LOCAL_DISTANCE + 1;
+
+	if (router_a == NULL) {
+		pr_info("node_distance: router_a NULL\n");
+		return 255;
+	}
+	if (router_b == NULL) {
+		pr_info("node_distance: router_b NULL\n");
+		return 255;
+	}
+
+	router_distance = 100;
+	router_recurse(router_a, router_b, 2);
+
+	return LOCAL_DISTANCE + router_distance;
+}
+
+static void __init init_topology_matrix(void)
+{
+	nasid_t row, col;
+
+	for (row = 0; row < MAX_NUMNODES; row++)
+		for (col = 0; col < MAX_NUMNODES; col++)
+			__node_distances[row][col] = -1;
+
+	for_each_online_node(row) {
+		for_each_online_node(col) {
+			__node_distances[row][col] =
+				compute_node_distance(row, col);
+		}
+	}
+}
+
+static void __init dump_topology(void)
+{
+	nasid_t nasid;
+	lboard_t *brd, *dest_brd;
+	int port;
+	int router_num = 0;
+	klrou_t *router;
+	nasid_t row, col;
+
+	pr_info("************** Topology ********************\n");
+
+	pr_info("    ");
+	for_each_online_node(col)
+		pr_cont("%02d ", col);
+	pr_cont("\n");
+	for_each_online_node(row) {
+		pr_info("%02d  ", row);
+		for_each_online_node(col)
+			pr_cont("%2d ", node_distance(row, col));
+		pr_cont("\n");
+	}
+
+	for_each_online_node(nasid) {
+		brd = find_lboard_class((lboard_t *)KL_CONFIG_INFO(nasid),
+					KLTYPE_ROUTER);
+
+		if (!brd)
+			continue;
+
+		do {
+			if (brd->brd_flags & DUPLICATE_BOARD)
+				continue;
+			pr_cont("Router %d:", router_num);
+			router_num++;
+
+			router = (klrou_t *)NODE_OFFSET_TO_K0(NASID_GET(brd), brd->brd_compts[0]);
+
+			for (port = 1; port <= MAX_ROUTER_PORTS; port++) {
+				if (router->rou_port[port].port_nasid == INVALID_NASID)
+					continue;
+
+				dest_brd = (lboard_t *)NODE_OFFSET_TO_K0(
+					router->rou_port[port].port_nasid,
+					router->rou_port[port].port_offset);
+
+				if (dest_brd->brd_type == KLTYPE_IP27)
+					pr_cont(" %d", dest_brd->brd_nasid);
+				if (dest_brd->brd_type == KLTYPE_ROUTER)
+					pr_cont(" r");
+			}
+			pr_cont("\n");
+
+		} while ( (brd = find_lboard_class(KLCF_NEXT(brd), KLTYPE_ROUTER)) );
+	}
+}
+
+static unsigned long __init slot_getbasepfn(nasid_t nasid, int slot)
+{
+	return ((unsigned long)nasid << PFN_NASIDSHFT) | (slot << SLOT_PFNSHIFT);
+}
+
+static unsigned long __init slot_psize_compute(nasid_t nasid, int slot)
+{
+	lboard_t *brd;
+	klmembnk_t *banks;
+	unsigned long size;
+
+	/* Find the node board */
+	brd = find_lboard((lboard_t *)KL_CONFIG_INFO(nasid), KLTYPE_IP27);
+	if (!brd)
+		return 0;
+
+	/* Get the memory bank structure */
+	banks = (klmembnk_t *) find_first_component(brd, KLSTRUCT_MEMBNK);
+	if (!banks)
+		return 0;
+
+	/* Size in _Megabytes_ */
+	size = (unsigned long)banks->membnk_bnksz[slot/4];
+
+	/* hack for 128 dimm banks */
+	if (size <= 128) {
+		if (slot % 4 == 0) {
+			size <<= 20;		/* size in bytes */
+			return size >> PAGE_SHIFT;
+		} else
+			return 0;
+	} else {
+		size /= 4;
+		size <<= 20;
+		return size >> PAGE_SHIFT;
+	}
+}
+
+static void __init mlreset(void)
+{
+	u64 region_mask;
+	nasid_t nasid;
+
+	master_nasid = get_nasid();
+
+	/*
+	 * Probe for all CPUs - this creates the cpumask and sets up the
+	 * mapping tables.  We need to do this as early as possible.
+	 */
+#ifdef CONFIG_SMP
+	cpu_node_probe();
+#endif
+
+	init_topology_matrix();
+	dump_topology();
+
+	region_mask = gen_region_mask();
+
+	setup_replication_mask();
+
+	/*
+	 * Set all nodes' calias sizes to 8k
+	 */
+	for_each_online_node(nasid) {
+		/*
+		 * Always have node 0 in the region mask, otherwise
+		 * CALIAS accesses get exceptions since the hub
+		 * thinks it is a node 0 address.
+		 */
+		REMOTE_HUB_S(nasid, PI_REGION_PRESENT, (region_mask | 1));
+		REMOTE_HUB_S(nasid, PI_CALIAS_SIZE, PI_CALIAS_SIZE_0);
+
+#ifdef LATER
+		/*
+		 * Set up all hubs to have a big window pointing at
+		 * widget 0. Memory mode, widget 0, offset 0
+		 */
+		REMOTE_HUB_S(nasid, IIO_ITTE(SWIN0_BIGWIN),
+			((HUB_PIO_MAP_TO_MEM << IIO_ITTE_IOSP_SHIFT) |
+			(0 << IIO_ITTE_WIDGET_SHIFT)));
+#endif
+	}
+}
+
+static void __init szmem(void)
+{
+	unsigned long slot_psize, slot0sz = 0, nodebytes;	/* Hack to detect problem configs */
+	int slot;
+	nasid_t node;
+
+	for_each_online_node(node) {
+		nodebytes = 0;
+		for (slot = 0; slot < MAX_MEM_SLOTS; slot++) {
+			slot_psize = slot_psize_compute(node, slot);
+			if (slot == 0)
+				slot0sz = slot_psize;
+			/*
+			 * We need to refine the hack when we have replicated
+			 * kernel text.
+			 */
+			nodebytes += (1LL << SLOT_SHIFT);
+
+			if (!slot_psize)
+				continue;
+
+			if ((nodebytes >> PAGE_SHIFT) * (sizeof(struct page)) >
+						(slot0sz << PAGE_SHIFT)) {
+				pr_info("Ignoring slot %d onwards on node %d\n",
+								slot, node);
+				slot = MAX_MEM_SLOTS;
+				continue;
+			}
+			memblock_add_node(PFN_PHYS(slot_getbasepfn(node, slot)),
+					  PFN_PHYS(slot_psize), node);
+		}
+	}
+}
+
+static void __init node_mem_init(nasid_t node)
+{
+	unsigned long slot_firstpfn = slot_getbasepfn(node, 0);
+	unsigned long slot_freepfn = node_getfirstfree(node);
+	unsigned long start_pfn, end_pfn;
+
+	get_pfn_range_for_nid(node, &start_pfn, &end_pfn);
+
+	/*
+	 * Allocate the node data structures on the node first.
+	 */
+	__node_data[node] = __va(slot_freepfn << PAGE_SHIFT);
+	memset(__node_data[node], 0, PAGE_SIZE);
+
+	NODE_DATA(node)->node_start_pfn = start_pfn;
+	NODE_DATA(node)->node_spanned_pages = end_pfn - start_pfn;
+
+	cpumask_clear(&hub_data(node)->h_cpus);
+
+	slot_freepfn += PFN_UP(sizeof(struct pglist_data) +
+			       sizeof(struct hub_data));
+
+	memblock_reserve(slot_firstpfn << PAGE_SHIFT,
+			 ((slot_freepfn - slot_firstpfn) << PAGE_SHIFT));
+}
+
+/*
+ * A node with nothing.	 We use it to avoid any special casing in
+ * cpumask_of_node
+ */
+static struct node_data null_node = {
+	.hub = {
+		.h_cpus = CPU_MASK_NONE
+	}
+};
+
+/*
+ * Currently, the intranode memory hole support assumes that each slot
+ * contains at least 32 MBytes of memory. We assume all bootmem data
+ * fits on the first slot.
+ */
+void __init prom_meminit(void)
+{
+	nasid_t node;
+
+	mlreset();
+	szmem();
+	max_low_pfn = PHYS_PFN(memblock_end_of_DRAM());
+
+	for (node = 0; node < MAX_NUMNODES; node++) {
+		if (node_online(node)) {
+			node_mem_init(node);
+			continue;
+		}
+		__node_data[node] = &null_node;
+	}
+}
+
+void __init prom_free_prom_memory(void)
+{
+	/* We got nothing to free here ...  */
+}
+
+extern void setup_zero_pages(void);
+
+void __init paging_init(void)
+{
+	unsigned long zones_size[MAX_NR_ZONES] = {0, };
+
+	pagetable_init();
+	zones_size[ZONE_NORMAL] = max_low_pfn;
+	free_area_init(zones_size);
+}
+
+void __init mem_init(void)
+{
+	high_memory = (void *) __va(get_num_physpages() << PAGE_SHIFT);
+	memblock_free_all();
+	setup_zero_pages();	/* This comes from node 0 */
+	mem_init_print_info(NULL);
+}
diff --git a/arch/mips/sgi-ip27/ip27-nmi.c b/arch/mips/sgi-ip27/ip27-nmi.c
new file mode 100644
index 000000000..84889b57d
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-nmi.c
@@ -0,0 +1,240 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/mmzone.h>
+#include <linux/nodemask.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/atomic.h>
+#include <asm/sn/types.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/nmi.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/agent.h>
+
+#if 0
+#define NODE_NUM_CPUS(n)	CNODE_NUM_CPUS(n)
+#else
+#define NODE_NUM_CPUS(n)	CPUS_PER_NODE
+#endif
+
+#define SEND_NMI(_nasid, _slice)	\
+	REMOTE_HUB_S((_nasid),  (PI_NMI_A + ((_slice) * PI_NMI_OFFSET)), 1)
+
+typedef unsigned long machreg_t;
+
+static arch_spinlock_t nmi_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+
+/*
+ * Let's see what else we need to do here. Set up sp, gp?
+ */
+void nmi_dump(void)
+{
+	void cont_nmi_dump(void);
+
+	cont_nmi_dump();
+}
+
+void install_cpu_nmi_handler(int slice)
+{
+	nmi_t *nmi_addr;
+
+	nmi_addr = (nmi_t *)NMI_ADDR(get_nasid(), slice);
+	if (nmi_addr->call_addr)
+		return;
+	nmi_addr->magic = NMI_MAGIC;
+	nmi_addr->call_addr = (void *)nmi_dump;
+	nmi_addr->call_addr_c =
+		(void *)(~((unsigned long)(nmi_addr->call_addr)));
+	nmi_addr->call_parm = 0;
+}
+
+/*
+ * Copy the cpu registers which have been saved in the IP27prom format
+ * into the eframe format for the node under consideration.
+ */
+
+void nmi_cpu_eframe_save(nasid_t nasid, int slice)
+{
+	struct reg_struct *nr;
+	int		i;
+
+	/* Get the pointer to the current cpu's register set. */
+	nr = (struct reg_struct *)
+		(TO_UNCAC(TO_NODE(nasid, IP27_NMI_KREGS_OFFSET)) +
+		slice * IP27_NMI_KREGS_CPU_SIZE);
+
+	pr_emerg("NMI nasid %d: slice %d\n", nasid, slice);
+
+	/*
+	 * Saved main processor registers
+	 */
+	for (i = 0; i < 32; ) {
+		if ((i % 4) == 0)
+			pr_emerg("$%2d   :", i);
+		pr_cont(" %016lx", nr->gpr[i]);
+
+		i++;
+		if ((i % 4) == 0)
+			pr_cont("\n");
+	}
+
+	pr_emerg("Hi    : (value lost)\n");
+	pr_emerg("Lo    : (value lost)\n");
+
+	/*
+	 * Saved cp0 registers
+	 */
+	pr_emerg("epc   : %016lx %pS\n", nr->epc, (void *)nr->epc);
+	pr_emerg("%s\n", print_tainted());
+	pr_emerg("ErrEPC: %016lx %pS\n", nr->error_epc, (void *)nr->error_epc);
+	pr_emerg("ra    : %016lx %pS\n", nr->gpr[31], (void *)nr->gpr[31]);
+	pr_emerg("Status: %08lx	      ", nr->sr);
+
+	if (nr->sr & ST0_KX)
+		pr_cont("KX ");
+	if (nr->sr & ST0_SX)
+		pr_cont("SX ");
+	if (nr->sr & ST0_UX)
+		pr_cont("UX ");
+
+	switch (nr->sr & ST0_KSU) {
+	case KSU_USER:
+		pr_cont("USER ");
+		break;
+	case KSU_SUPERVISOR:
+		pr_cont("SUPERVISOR ");
+		break;
+	case KSU_KERNEL:
+		pr_cont("KERNEL ");
+		break;
+	default:
+		pr_cont("BAD_MODE ");
+		break;
+	}
+
+	if (nr->sr & ST0_ERL)
+		pr_cont("ERL ");
+	if (nr->sr & ST0_EXL)
+		pr_cont("EXL ");
+	if (nr->sr & ST0_IE)
+		pr_cont("IE ");
+	pr_cont("\n");
+
+	pr_emerg("Cause : %08lx\n", nr->cause);
+	pr_emerg("PrId  : %08x\n", read_c0_prid());
+	pr_emerg("BadVA : %016lx\n", nr->badva);
+	pr_emerg("CErr  : %016lx\n", nr->cache_err);
+	pr_emerg("NMI_SR: %016lx\n", nr->nmi_sr);
+
+	pr_emerg("\n");
+}
+
+void nmi_dump_hub_irq(nasid_t nasid, int slice)
+{
+	u64 mask0, mask1, pend0, pend1;
+
+	if (slice == 0) {				/* Slice A */
+		mask0 = REMOTE_HUB_L(nasid, PI_INT_MASK0_A);
+		mask1 = REMOTE_HUB_L(nasid, PI_INT_MASK1_A);
+	} else {					/* Slice B */
+		mask0 = REMOTE_HUB_L(nasid, PI_INT_MASK0_B);
+		mask1 = REMOTE_HUB_L(nasid, PI_INT_MASK1_B);
+	}
+
+	pend0 = REMOTE_HUB_L(nasid, PI_INT_PEND0);
+	pend1 = REMOTE_HUB_L(nasid, PI_INT_PEND1);
+
+	pr_emerg("PI_INT_MASK0: %16llx PI_INT_MASK1: %16llx\n", mask0, mask1);
+	pr_emerg("PI_INT_PEND0: %16llx PI_INT_PEND1: %16llx\n", pend0, pend1);
+	pr_emerg("\n\n");
+}
+
+/*
+ * Copy the cpu registers which have been saved in the IP27prom format
+ * into the eframe format for the node under consideration.
+ */
+void nmi_node_eframe_save(nasid_t nasid)
+{
+	int slice;
+
+	if (nasid == INVALID_NASID)
+		return;
+
+	/* Save the registers into eframe for each cpu */
+	for (slice = 0; slice < NODE_NUM_CPUS(slice); slice++) {
+		nmi_cpu_eframe_save(nasid, slice);
+		nmi_dump_hub_irq(nasid, slice);
+	}
+}
+
+/*
+ * Save the nmi cpu registers for all cpus in the system.
+ */
+void
+nmi_eframes_save(void)
+{
+	nasid_t nasid;
+
+	for_each_online_node(nasid)
+		nmi_node_eframe_save(nasid);
+}
+
+void
+cont_nmi_dump(void)
+{
+#ifndef REAL_NMI_SIGNAL
+	static atomic_t nmied_cpus = ATOMIC_INIT(0);
+
+	atomic_inc(&nmied_cpus);
+#endif
+	/*
+	 * Only allow 1 cpu to proceed
+	 */
+	arch_spin_lock(&nmi_lock);
+
+#ifdef REAL_NMI_SIGNAL
+	/*
+	 * Wait up to 15 seconds for the other cpus to respond to the NMI.
+	 * If a cpu has not responded after 10 sec, send it 1 additional NMI.
+	 * This is for 2 reasons:
+	 *	- sometimes a MMSC fail to NMI all cpus.
+	 *	- on 512p SN0 system, the MMSC will only send NMIs to
+	 *	  half the cpus. Unfortunately, we don't know which cpus may be
+	 *	  NMIed - it depends on how the site chooses to configure.
+	 *
+	 * Note: it has been measure that it takes the MMSC up to 2.3 secs to
+	 * send NMIs to all cpus on a 256p system.
+	 */
+	for (i=0; i < 1500; i++) {
+		for_each_online_node(node)
+			if (NODEPDA(node)->dump_count == 0)
+				break;
+		if (node == MAX_NUMNODES)
+			break;
+		if (i == 1000) {
+			for_each_online_node(node)
+				if (NODEPDA(node)->dump_count == 0) {
+					cpu = cpumask_first(cpumask_of_node(node));
+					for (n=0; n < CNODE_NUM_CPUS(node); cpu++, n++) {
+						CPUMASK_SETB(nmied_cpus, cpu);
+						/*
+						 * cputonasid, cputoslice
+						 * needs kernel cpuid
+						 */
+						SEND_NMI((cputonasid(cpu)), (cputoslice(cpu)));
+					}
+				}
+
+		}
+		udelay(10000);
+	}
+#else
+	while (atomic_read(&nmied_cpus) != num_online_cpus());
+#endif
+
+	/*
+	 * Save the nmi cpu registers for all cpu in the eframe format.
+	 */
+	nmi_eframes_save();
+	LOCAL_HUB_S(NI_PORT_RESET, NPR_PORTRESET | NPR_LOCALRESET);
+}
diff --git a/arch/mips/sgi-ip27/ip27-reset.c b/arch/mips/sgi-ip27/ip27-reset.c
new file mode 100644
index 000000000..5ac5ad638
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-reset.c
@@ -0,0 +1,81 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Reset an IP27.
+ *
+ * Copyright (C) 1997, 1998, 1999, 2000, 06 by Ralf Baechle
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ */
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/smp.h>
+#include <linux/mmzone.h>
+#include <linux/nodemask.h>
+#include <linux/pm.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/reboot.h>
+#include <asm/sgialib.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/agent.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/gda.h>
+
+#include "ip27-common.h"
+
+void machine_restart(char *command) __noreturn;
+void machine_halt(void) __noreturn;
+void machine_power_off(void) __noreturn;
+
+#define noreturn while(1);				/* Silence gcc.	 */
+
+/* XXX How to pass the reboot command to the firmware??? */
+static void ip27_machine_restart(char *command)
+{
+#if 0
+	int i;
+#endif
+
+	printk("Reboot started from CPU %d\n", smp_processor_id());
+#ifdef CONFIG_SMP
+	smp_send_stop();
+#endif
+#if 0
+	for_each_online_node(i)
+		REMOTE_HUB_S(i, PROMOP_REG, PROMOP_REBOOT);
+#else
+	LOCAL_HUB_S(NI_PORT_RESET, NPR_PORTRESET | NPR_LOCALRESET);
+#endif
+	noreturn;
+}
+
+static void ip27_machine_halt(void)
+{
+	int i;
+
+#ifdef CONFIG_SMP
+	smp_send_stop();
+#endif
+	for_each_online_node(i)
+		REMOTE_HUB_S(i, PROMOP_REG, PROMOP_RESTART);
+	LOCAL_HUB_S(NI_PORT_RESET, NPR_PORTRESET | NPR_LOCALRESET);
+	noreturn;
+}
+
+static void ip27_machine_power_off(void)
+{
+	/* To do ...  */
+	noreturn;
+}
+
+void ip27_reboot_setup(void)
+{
+	_machine_restart = ip27_machine_restart;
+	_machine_halt = ip27_machine_halt;
+	pm_power_off = ip27_machine_power_off;
+}
diff --git a/arch/mips/sgi-ip27/ip27-smp.c b/arch/mips/sgi-ip27/ip27-smp.c
new file mode 100644
index 000000000..5d2652a1d
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-smp.c
@@ -0,0 +1,189 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * Copyright (C) 2000 - 2001 by Kanoj Sarcar (kanoj@sgi.com)
+ * Copyright (C) 2000 - 2001 by Silicon Graphics, Inc.
+ */
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/topology.h>
+#include <linux/nodemask.h>
+
+#include <asm/page.h>
+#include <asm/processor.h>
+#include <asm/ptrace.h>
+#include <asm/sn/agent.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/gda.h>
+#include <asm/sn/intr.h>
+#include <asm/sn/klconfig.h>
+#include <asm/sn/launch.h>
+#include <asm/sn/mapped_kernel.h>
+#include <asm/sn/types.h>
+
+#include "ip27-common.h"
+
+static int node_scan_cpus(nasid_t nasid, int highest)
+{
+	static int cpus_found;
+	lboard_t *brd;
+	klcpu_t *acpu;
+	cpuid_t cpuid;
+
+	brd = find_lboard((lboard_t *)KL_CONFIG_INFO(nasid), KLTYPE_IP27);
+
+	do {
+		acpu = (klcpu_t *)find_first_component(brd, KLSTRUCT_CPU);
+		while (acpu) {
+			cpuid = acpu->cpu_info.virtid;
+			/* Only let it join in if it's marked enabled */
+			if ((acpu->cpu_info.flags & KLINFO_ENABLE) &&
+			    (cpus_found != NR_CPUS)) {
+				if (cpuid > highest)
+					highest = cpuid;
+				set_cpu_possible(cpuid, true);
+				cputonasid(cpus_found) = nasid;
+				cputoslice(cpus_found) = acpu->cpu_info.physid;
+				sn_cpu_info[cpus_found].p_speed =
+							acpu->cpu_speed;
+				cpus_found++;
+			}
+			acpu = (klcpu_t *)find_component(brd, (klinfo_t *)acpu,
+								KLSTRUCT_CPU);
+		}
+		brd = KLCF_NEXT(brd);
+		if (!brd)
+			break;
+
+		brd = find_lboard(brd, KLTYPE_IP27);
+	} while (brd);
+
+	return highest;
+}
+
+void cpu_node_probe(void)
+{
+	int i, highest = 0;
+	gda_t *gdap = GDA;
+
+	nodes_clear(node_online_map);
+	for (i = 0; i < MAX_NUMNODES; i++) {
+		nasid_t nasid = gdap->g_nasidtable[i];
+		if (nasid == INVALID_NASID)
+			break;
+		node_set_online(nasid);
+		highest = node_scan_cpus(nasid, highest);
+	}
+
+	printk("Discovered %d cpus on %d nodes\n", highest + 1, num_online_nodes());
+}
+
+static __init void intr_clear_all(nasid_t nasid)
+{
+	int i;
+
+	REMOTE_HUB_S(nasid, PI_INT_MASK0_A, 0);
+	REMOTE_HUB_S(nasid, PI_INT_MASK0_B, 0);
+	REMOTE_HUB_S(nasid, PI_INT_MASK1_A, 0);
+	REMOTE_HUB_S(nasid, PI_INT_MASK1_B, 0);
+
+	for (i = 0; i < 128; i++)
+		REMOTE_HUB_CLR_INTR(nasid, i);
+}
+
+static void ip27_send_ipi_single(int destid, unsigned int action)
+{
+	int irq;
+
+	switch (action) {
+	case SMP_RESCHEDULE_YOURSELF:
+		irq = CPU_RESCHED_A_IRQ;
+		break;
+	case SMP_CALL_FUNCTION:
+		irq = CPU_CALL_A_IRQ;
+		break;
+	default:
+		panic("sendintr");
+	}
+
+	irq += cputoslice(destid);
+
+	/*
+	 * Set the interrupt bit associated with the CPU we want to
+	 * send the interrupt to.
+	 */
+	REMOTE_HUB_SEND_INTR(cpu_to_node(destid), irq);
+}
+
+static void ip27_send_ipi_mask(const struct cpumask *mask, unsigned int action)
+{
+	unsigned int i;
+
+	for_each_cpu(i, mask)
+		ip27_send_ipi_single(i, action);
+}
+
+static void ip27_init_cpu(void)
+{
+	per_cpu_init();
+}
+
+static void ip27_smp_finish(void)
+{
+	hub_rt_clock_event_init();
+	local_irq_enable();
+}
+
+/*
+ * Launch a slave into smp_bootstrap().	 It doesn't take an argument, and we
+ * set sp to the kernel stack of the newly created idle process, gp to the proc
+ * struct so that current_thread_info() will work.
+ */
+static int ip27_boot_secondary(int cpu, struct task_struct *idle)
+{
+	unsigned long gp = (unsigned long)task_thread_info(idle);
+	unsigned long sp = __KSTK_TOS(idle);
+
+	LAUNCH_SLAVE(cputonasid(cpu), cputoslice(cpu),
+		(launch_proc_t)MAPPED_KERN_RW_TO_K0(smp_bootstrap),
+		0, (void *) sp, (void *) gp);
+	return 0;
+}
+
+static void __init ip27_smp_setup(void)
+{
+	nasid_t nasid;
+
+	for_each_online_node(nasid) {
+		if (nasid == 0)
+			continue;
+		intr_clear_all(nasid);
+	}
+
+	replicate_kernel_text();
+
+	/*
+	 * PROM sets up system, that boot cpu is always first CPU on nasid 0
+	 */
+	cputonasid(0) = 0;
+	cputoslice(0) = LOCAL_HUB_L(PI_CPU_NUM);
+}
+
+static void __init ip27_prepare_cpus(unsigned int max_cpus)
+{
+	/* We already did everything necessary earlier */
+}
+
+const struct plat_smp_ops ip27_smp_ops = {
+	.send_ipi_single	= ip27_send_ipi_single,
+	.send_ipi_mask		= ip27_send_ipi_mask,
+	.init_secondary		= ip27_init_cpu,
+	.smp_finish		= ip27_smp_finish,
+	.boot_secondary		= ip27_boot_secondary,
+	.smp_setup		= ip27_smp_setup,
+	.prepare_cpus		= ip27_prepare_cpus,
+	.prepare_boot_cpu	= ip27_init_cpu,
+};
diff --git a/arch/mips/sgi-ip27/ip27-timer.c b/arch/mips/sgi-ip27/ip27-timer.c
new file mode 100644
index 000000000..79c434fec
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-timer.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copytight (C) 1999, 2000, 05, 06 Ralf Baechle (ralf@linux-mips.org)
+ * Copytight (C) 1999, 2000 Silicon Graphics, Inc.
+ */
+#include <linux/bcd.h>
+#include <linux/clockchips.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/sched_clock.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/param.h>
+#include <linux/smp.h>
+#include <linux/time.h>
+#include <linux/timex.h>
+#include <linux/mm.h>
+#include <linux/platform_device.h>
+
+#include <asm/time.h>
+#include <asm/sgialib.h>
+#include <asm/sn/klconfig.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/agent.h>
+
+#include "ip27-common.h"
+
+static int rt_next_event(unsigned long delta, struct clock_event_device *evt)
+{
+	unsigned int cpu = smp_processor_id();
+	int slice = cputoslice(cpu);
+	unsigned long cnt;
+
+	cnt = LOCAL_HUB_L(PI_RT_COUNT);
+	cnt += delta;
+	LOCAL_HUB_S(PI_RT_COMPARE_A + PI_COUNT_OFFSET * slice, cnt);
+
+	return LOCAL_HUB_L(PI_RT_COUNT) >= cnt ? -ETIME : 0;
+}
+
+static DEFINE_PER_CPU(struct clock_event_device, hub_rt_clockevent);
+static DEFINE_PER_CPU(char [11], hub_rt_name);
+
+static irqreturn_t hub_rt_counter_handler(int irq, void *dev_id)
+{
+	unsigned int cpu = smp_processor_id();
+	struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
+	int slice = cputoslice(cpu);
+
+	/*
+	 * Ack
+	 */
+	LOCAL_HUB_S(PI_RT_PEND_A + PI_COUNT_OFFSET * slice, 0);
+	cd->event_handler(cd);
+
+	return IRQ_HANDLED;
+}
+
+struct irqaction hub_rt_irqaction = {
+	.handler	= hub_rt_counter_handler,
+	.percpu_dev_id	= &hub_rt_clockevent,
+	.flags		= IRQF_PERCPU | IRQF_TIMER,
+	.name		= "hub-rt",
+};
+
+/*
+ * This is a hack; we really need to figure these values out dynamically
+ *
+ * Since 800 ns works very well with various HUB frequencies, such as
+ * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
+ *
+ * Ralf: which clock rate is used to feed the counter?
+ */
+#define NSEC_PER_CYCLE		800
+#define CYCLES_PER_SEC		(NSEC_PER_SEC / NSEC_PER_CYCLE)
+
+void hub_rt_clock_event_init(void)
+{
+	unsigned int cpu = smp_processor_id();
+	struct clock_event_device *cd = &per_cpu(hub_rt_clockevent, cpu);
+	unsigned char *name = per_cpu(hub_rt_name, cpu);
+
+	sprintf(name, "hub-rt %d", cpu);
+	cd->name		= name;
+	cd->features		= CLOCK_EVT_FEAT_ONESHOT;
+	clockevent_set_clock(cd, CYCLES_PER_SEC);
+	cd->max_delta_ns	= clockevent_delta2ns(0xfffffffffffff, cd);
+	cd->max_delta_ticks	= 0xfffffffffffff;
+	cd->min_delta_ns	= clockevent_delta2ns(0x300, cd);
+	cd->min_delta_ticks	= 0x300;
+	cd->rating		= 200;
+	cd->irq			= IP27_RT_TIMER_IRQ;
+	cd->cpumask		= cpumask_of(cpu);
+	cd->set_next_event	= rt_next_event;
+	clockevents_register_device(cd);
+
+	enable_percpu_irq(IP27_RT_TIMER_IRQ, IRQ_TYPE_NONE);
+}
+
+static void __init hub_rt_clock_event_global_init(void)
+{
+	irq_set_handler(IP27_RT_TIMER_IRQ, handle_percpu_devid_irq);
+	irq_set_percpu_devid(IP27_RT_TIMER_IRQ);
+	setup_percpu_irq(IP27_RT_TIMER_IRQ, &hub_rt_irqaction);
+}
+
+static u64 hub_rt_read(struct clocksource *cs)
+{
+	return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
+}
+
+struct clocksource hub_rt_clocksource = {
+	.name	= "HUB-RT",
+	.rating = 200,
+	.read	= hub_rt_read,
+	.mask	= CLOCKSOURCE_MASK(52),
+	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static u64 notrace hub_rt_read_sched_clock(void)
+{
+	return REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT);
+}
+
+static void __init hub_rt_clocksource_init(void)
+{
+	struct clocksource *cs = &hub_rt_clocksource;
+
+	clocksource_register_hz(cs, CYCLES_PER_SEC);
+
+	sched_clock_register(hub_rt_read_sched_clock, 52, CYCLES_PER_SEC);
+}
+
+void __init plat_time_init(void)
+{
+	hub_rt_clocksource_init();
+	hub_rt_clock_event_global_init();
+	hub_rt_clock_event_init();
+}
+
+void hub_rtc_init(nasid_t nasid)
+{
+
+	/*
+	 * We only need to initialize the current node.
+	 * If this is not the current node then it is a cpuless
+	 * node and timeouts will not happen there.
+	 */
+	if (get_nasid() == nasid) {
+		LOCAL_HUB_S(PI_RT_EN_A, 1);
+		LOCAL_HUB_S(PI_RT_EN_B, 1);
+		LOCAL_HUB_S(PI_PROF_EN_A, 0);
+		LOCAL_HUB_S(PI_PROF_EN_B, 0);
+		LOCAL_HUB_S(PI_RT_COUNT, 0);
+		LOCAL_HUB_S(PI_RT_PEND_A, 0);
+		LOCAL_HUB_S(PI_RT_PEND_B, 0);
+	}
+}
diff --git a/arch/mips/sgi-ip27/ip27-xtalk.c b/arch/mips/sgi-ip27/ip27-xtalk.c
new file mode 100644
index 000000000..5143d1cf8
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-xtalk.c
@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 1999, 2000 Ralf Baechle (ralf@gnu.org)
+ * Copyright (C) 1999, 2000 Silcon Graphics, Inc.
+ * Copyright (C) 2004 Christoph Hellwig.
+ *
+ * Generic XTALK initialization code
+ */
+
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/sgi-w1.h>
+#include <linux/platform_data/xtalk-bridge.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/types.h>
+#include <asm/sn/klconfig.h>
+#include <asm/pci/bridge.h>
+#include <asm/xtalk/xtalk.h>
+
+
+#define XBOW_WIDGET_PART_NUM	0x0
+#define XXBOW_WIDGET_PART_NUM	0xd000	/* Xbow in Xbridge */
+#define BASE_XBOW_PORT		8     /* Lowest external port */
+
+static void bridge_platform_create(nasid_t nasid, int widget, int masterwid)
+{
+	struct xtalk_bridge_platform_data *bd;
+	struct sgi_w1_platform_data *wd;
+	struct platform_device *pdev_wd;
+	struct platform_device *pdev_bd;
+	struct resource w1_res;
+	unsigned long offset;
+
+	offset = NODE_OFFSET(nasid);
+
+	wd = kzalloc(sizeof(*wd), GFP_KERNEL);
+	if (!wd) {
+		pr_warn("xtalk:n%d/%x bridge create out of memory\n", nasid, widget);
+		return;
+	}
+
+	snprintf(wd->dev_id, sizeof(wd->dev_id), "bridge-%012lx",
+		 offset + (widget << SWIN_SIZE_BITS));
+
+	memset(&w1_res, 0, sizeof(w1_res));
+	w1_res.start = offset + (widget << SWIN_SIZE_BITS) +
+				offsetof(struct bridge_regs, b_nic);
+	w1_res.end = w1_res.start + 3;
+	w1_res.flags = IORESOURCE_MEM;
+
+	pdev_wd = platform_device_alloc("sgi_w1", PLATFORM_DEVID_AUTO);
+	if (!pdev_wd) {
+		pr_warn("xtalk:n%d/%x bridge create out of memory\n", nasid, widget);
+		goto err_kfree_wd;
+	}
+	if (platform_device_add_resources(pdev_wd, &w1_res, 1)) {
+		pr_warn("xtalk:n%d/%x bridge failed to add platform resources.\n", nasid, widget);
+		goto err_put_pdev_wd;
+	}
+	if (platform_device_add_data(pdev_wd, wd, sizeof(*wd))) {
+		pr_warn("xtalk:n%d/%x bridge failed to add platform data.\n", nasid, widget);
+		goto err_put_pdev_wd;
+	}
+	if (platform_device_add(pdev_wd)) {
+		pr_warn("xtalk:n%d/%x bridge failed to add platform device.\n", nasid, widget);
+		goto err_put_pdev_wd;
+	}
+	/* platform_device_add_data() duplicates the data */
+	kfree(wd);
+
+	bd = kzalloc(sizeof(*bd), GFP_KERNEL);
+	if (!bd) {
+		pr_warn("xtalk:n%d/%x bridge create out of memory\n", nasid, widget);
+		goto err_unregister_pdev_wd;
+	}
+	pdev_bd = platform_device_alloc("xtalk-bridge", PLATFORM_DEVID_AUTO);
+	if (!pdev_bd) {
+		pr_warn("xtalk:n%d/%x bridge create out of memory\n", nasid, widget);
+		goto err_kfree_bd;
+	}
+
+
+	bd->bridge_addr = RAW_NODE_SWIN_BASE(nasid, widget);
+	bd->intr_addr	= BIT_ULL(47) + 0x01800000 + PI_INT_PEND_MOD;
+	bd->nasid	= nasid;
+	bd->masterwid	= masterwid;
+
+	bd->mem.name	= "Bridge PCI MEM";
+	bd->mem.start	= offset + (widget << SWIN_SIZE_BITS) + BRIDGE_DEVIO0;
+	bd->mem.end	= offset + (widget << SWIN_SIZE_BITS) + SWIN_SIZE - 1;
+	bd->mem.flags	= IORESOURCE_MEM;
+	bd->mem_offset	= offset;
+
+	bd->io.name	= "Bridge PCI IO";
+	bd->io.start	= offset + (widget << SWIN_SIZE_BITS) + BRIDGE_DEVIO0;
+	bd->io.end	= offset + (widget << SWIN_SIZE_BITS) + SWIN_SIZE - 1;
+	bd->io.flags	= IORESOURCE_IO;
+	bd->io_offset	= offset;
+
+	if (platform_device_add_data(pdev_bd, bd, sizeof(*bd))) {
+		pr_warn("xtalk:n%d/%x bridge failed to add platform data.\n", nasid, widget);
+		goto err_put_pdev_bd;
+	}
+	if (platform_device_add(pdev_bd)) {
+		pr_warn("xtalk:n%d/%x bridge failed to add platform device.\n", nasid, widget);
+		goto err_put_pdev_bd;
+	}
+	/* platform_device_add_data() duplicates the data */
+	kfree(bd);
+	pr_info("xtalk:n%d/%x bridge widget\n", nasid, widget);
+	return;
+
+err_put_pdev_bd:
+	platform_device_put(pdev_bd);
+err_kfree_bd:
+	kfree(bd);
+err_unregister_pdev_wd:
+	platform_device_unregister(pdev_wd);
+	return;
+err_put_pdev_wd:
+	platform_device_put(pdev_wd);
+err_kfree_wd:
+	kfree(wd);
+	return;
+}
+
+static int probe_one_port(nasid_t nasid, int widget, int masterwid)
+{
+	widgetreg_t		widget_id;
+	xwidget_part_num_t	partnum;
+
+	widget_id = *(volatile widgetreg_t *)
+		(RAW_NODE_SWIN_BASE(nasid, widget) + WIDGET_ID);
+	partnum = XWIDGET_PART_NUM(widget_id);
+
+	switch (partnum) {
+	case BRIDGE_WIDGET_PART_NUM:
+	case XBRIDGE_WIDGET_PART_NUM:
+		bridge_platform_create(nasid, widget, masterwid);
+		break;
+	default:
+		pr_info("xtalk:n%d/%d unknown widget (0x%x)\n",
+			nasid, widget, partnum);
+		break;
+	}
+
+	return 0;
+}
+
+static int xbow_probe(nasid_t nasid)
+{
+	lboard_t *brd;
+	klxbow_t *xbow_p;
+	unsigned masterwid, i;
+
+	/*
+	 * found xbow, so may have multiple bridges
+	 * need to probe xbow
+	 */
+	brd = find_lboard((lboard_t *)KL_CONFIG_INFO(nasid), KLTYPE_MIDPLANE8);
+	if (!brd)
+		return -ENODEV;
+
+	xbow_p = (klxbow_t *)find_component(brd, NULL, KLSTRUCT_XBOW);
+	if (!xbow_p)
+		return -ENODEV;
+
+	/*
+	 * Okay, here's a xbow. Let's arbitrate and find
+	 * out if we should initialize it. Set enabled
+	 * hub connected at highest or lowest widget as
+	 * master.
+	 */
+#ifdef WIDGET_A
+	i = HUB_WIDGET_ID_MAX + 1;
+	do {
+		i--;
+	} while ((!XBOW_PORT_TYPE_HUB(xbow_p, i)) ||
+		 (!XBOW_PORT_IS_ENABLED(xbow_p, i)));
+#else
+	i = HUB_WIDGET_ID_MIN - 1;
+	do {
+		i++;
+	} while ((!XBOW_PORT_TYPE_HUB(xbow_p, i)) ||
+		 (!XBOW_PORT_IS_ENABLED(xbow_p, i)));
+#endif
+
+	masterwid = i;
+	if (nasid != XBOW_PORT_NASID(xbow_p, i))
+		return 1;
+
+	for (i = HUB_WIDGET_ID_MIN; i <= HUB_WIDGET_ID_MAX; i++) {
+		if (XBOW_PORT_IS_ENABLED(xbow_p, i) &&
+		    XBOW_PORT_TYPE_IO(xbow_p, i))
+			probe_one_port(nasid, i, masterwid);
+	}
+
+	return 0;
+}
+
+static void xtalk_probe_node(nasid_t nasid)
+{
+	volatile u64		hubreg;
+	xwidget_part_num_t	partnum;
+	widgetreg_t		widget_id;
+
+	hubreg = REMOTE_HUB_L(nasid, IIO_LLP_CSR);
+
+	/* check whether the link is up */
+	if (!(hubreg & IIO_LLP_CSR_IS_UP))
+		return;
+
+	widget_id = *(volatile widgetreg_t *)
+		       (RAW_NODE_SWIN_BASE(nasid, 0x0) + WIDGET_ID);
+	partnum = XWIDGET_PART_NUM(widget_id);
+
+	switch (partnum) {
+	case BRIDGE_WIDGET_PART_NUM:
+		bridge_platform_create(nasid, 0x8, 0xa);
+		break;
+	case XBOW_WIDGET_PART_NUM:
+	case XXBOW_WIDGET_PART_NUM:
+		pr_info("xtalk:n%d/0 xbow widget\n", nasid);
+		xbow_probe(nasid);
+		break;
+	default:
+		pr_info("xtalk:n%d/0 unknown widget (0x%x)\n", nasid, partnum);
+		break;
+	}
+}
+
+static int __init xtalk_init(void)
+{
+	nasid_t nasid;
+
+	for_each_online_node(nasid)
+		xtalk_probe_node(nasid);
+
+	return 0;
+}
+arch_initcall(xtalk_init);