powerpc: Add WSP platform

Add a platform for the Wire Speed Processor, based on the PPC A2.

This includes code for the ICS & OPB interrupt controllers, as well
as a SCOM backend, and SCOM based cpu bringup.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Jack Miller <jack@codezen.org>
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/wsp/smp.c

@@ -0,0 +1,87 @@
+/*
+ *  SMP Support for A2 platforms
+ *
+ *  Copyright 2007 Benjamin Herrenschmidt, IBM Corp.
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/cpumask.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/smp.h>
+
+#include <asm/dbell.h>
+#include <asm/machdep.h>
+#include <asm/xics.h>
+
+#include "ics.h"
+#include "wsp.h"
+
+static void __devinit smp_a2_setup_cpu(int cpu)
+{
+	doorbell_setup_this_cpu();
+
+	if (cpu != boot_cpuid)
+		xics_setup_cpu();
+}
+
+int __devinit smp_a2_kick_cpu(int nr)
+{
+	const char *enable_method;
+	struct device_node *np;
+	int thr_idx;
+
+	if (nr < 0 || nr >= NR_CPUS)
+		return -ENOENT;
+
+	np = of_get_cpu_node(nr, &thr_idx);
+	if (!np)
+		return -ENODEV;
+
+	enable_method = of_get_property(np, "enable-method", NULL);
+	pr_devel("CPU%d has enable-method: \"%s\"\n", nr, enable_method);
+
+	if (!enable_method) {
+                printk(KERN_ERR "CPU%d has no enable-method\n", nr);
+		return -ENOENT;
+	} else if (strcmp(enable_method, "ibm,a2-scom") == 0) {
+		if (a2_scom_startup_cpu(nr, thr_idx, np))
+			return -1;
+	} else {
+		printk(KERN_ERR "CPU%d: Don't understand enable-method \"%s\"\n",
+                       nr, enable_method);
+		return -EINVAL;
+	}
+
+	/*
+	 * The processor is currently spinning, waiting for the
+	 * cpu_start field to become non-zero After we set cpu_start,
+	 * the processor will continue on to secondary_start
+	 */
+	paca[nr].cpu_start = 1;
+
+	return 0;
+}
+
+static int __init smp_a2_probe(void)
+{
+	return cpus_weight(cpu_possible_map);
+}
+
+static struct smp_ops_t a2_smp_ops = {
+	.message_pass	= doorbell_message_pass,
+	.probe		= smp_a2_probe,
+	.kick_cpu	= smp_a2_kick_cpu,
+	.setup_cpu	= smp_a2_setup_cpu,
+};
+
+void __init a2_setup_smp(void)
+{
+	smp_ops = &a2_smp_ops;
+}