From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Thu, 11 Apr 2024 10:27:49 +0200
Subject: Adding upstream version 6.6.15.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 arch/sparc/kernel/devices.c | 138 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 arch/sparc/kernel/devices.c

(limited to 'arch/sparc/kernel/devices.c')

diff --git a/arch/sparc/kernel/devices.c b/arch/sparc/kernel/devices.c
new file mode 100644
index 0000000000..23b6e50d4a
--- /dev/null
+++ b/arch/sparc/kernel/devices.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+/* devices.c: Initial scan of the prom device tree for important
+ *	      Sparc device nodes which we need to find.
+ *
+ * This is based on the sparc64 version, but sun4m doesn't always use
+ * the hardware MIDs, so be careful.
+ *
+ * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#include <linux/kernel.h>
+#include <linux/threads.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+
+#include <asm/page.h>
+#include <asm/oplib.h>
+#include <asm/prom.h>
+#include <asm/smp.h>
+#include <asm/cpudata.h>
+#include <asm/cpu_type.h>
+#include <asm/setup.h>
+
+#include "kernel.h"
+
+static char *cpu_mid_prop(void)
+{
+	if (sparc_cpu_model == sun4d)
+		return "cpu-id";
+	return "mid";
+}
+
+static int check_cpu_node(phandle nd, int *cur_inst,
+		int (*compare)(phandle, int, void *), void *compare_arg,
+		phandle *prom_node, int *mid)
+{
+	if (!compare(nd, *cur_inst, compare_arg)) {
+		if (prom_node)
+			*prom_node = nd;
+		if (mid) {
+			*mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
+			if (sparc_cpu_model == sun4m)
+				*mid &= 3;
+		}
+		return 0;
+	}
+
+	(*cur_inst)++;
+
+	return -ENODEV;
+}
+
+static int __cpu_find_by(int (*compare)(phandle, int, void *),
+		void *compare_arg, phandle *prom_node, int *mid)
+{
+	struct device_node *dp;
+	int cur_inst;
+
+	cur_inst = 0;
+	for_each_node_by_type(dp, "cpu") {
+		int err = check_cpu_node(dp->phandle, &cur_inst,
+					 compare, compare_arg,
+					 prom_node, mid);
+		if (!err) {
+			of_node_put(dp);
+			return 0;
+		}
+	}
+
+	return -ENODEV;
+}
+
+static int cpu_instance_compare(phandle nd, int instance, void *_arg)
+{
+	int desired_instance = (int) _arg;
+
+	if (instance == desired_instance)
+		return 0;
+	return -ENODEV;
+}
+
+int cpu_find_by_instance(int instance, phandle *prom_node, int *mid)
+{
+	return __cpu_find_by(cpu_instance_compare, (void *)instance,
+			     prom_node, mid);
+}
+
+static int cpu_mid_compare(phandle nd, int instance, void *_arg)
+{
+	int desired_mid = (int) _arg;
+	int this_mid;
+
+	this_mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
+	if (this_mid == desired_mid
+	    || (sparc_cpu_model == sun4m && (this_mid & 3) == desired_mid))
+		return 0;
+	return -ENODEV;
+}
+
+int cpu_find_by_mid(int mid, phandle *prom_node)
+{
+	return __cpu_find_by(cpu_mid_compare, (void *)mid,
+			     prom_node, NULL);
+}
+
+/* sun4m uses truncated mids since we base the cpuid on the ttable/irqset
+ * address (0-3).  This gives us the true hardware mid, which might have
+ * some other bits set.  On 4d hardware and software mids are the same.
+ */
+int cpu_get_hwmid(phandle prom_node)
+{
+	return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
+}
+
+void __init device_scan(void)
+{
+	printk(KERN_NOTICE "Booting Linux...\n");
+
+#ifndef CONFIG_SMP
+	{
+		phandle cpu_node;
+		int err;
+		err = cpu_find_by_instance(0, &cpu_node, NULL);
+		if (err) {
+			/* Probably a sun4e, Sun is trying to trick us ;-) */
+			prom_printf("No cpu nodes, cannot continue\n");
+			prom_halt();
+		}
+		cpu_data(0).clock_tick = prom_getintdefault(cpu_node,
+							    "clock-frequency",
+							    0);
+	}
+#endif /* !CONFIG_SMP */
+
+	auxio_probe();
+	auxio_power_probe();
+}
-- 
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