[PATCH v6 4/9] ARM: vexpress: Use FDT data in platform SMP calls

[Pawel Moll]

If ct_desc is not set (so a board was booted with DT machine ID)
try to look for "arm,cortex-a9-scu" node and initialize the SCU
using base address in "reg" property.

Otherwise assume that there is no special SCU initialization
required and initialize CPUs basing on numbers of "cpu" type
devices in "cpus" node of the Device Tree.

Signed-off-by: Pawel Moll <pawel.moll at arm.com>
---
 arch/arm/mach-vexpress/platsmp.c |  148 +++++++++++++++++++++++++++++++++++++-
 1 files changed, 146 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c
index a1ed6d6..d49e800d 100644
--- a/arch/arm/mach-vexpress/platsmp.c
+++ b/arch/arm/mach-vexpress/platsmp.c
@@ -12,6 +12,11 @@
 #include <linux/errno.h>
 #include <linux/smp.h>
 #include <linux/io.h>
+#include <linux/of_fdt.h>
+
+#include <asm/smp_scu.h>
+#include <asm/hardware/gic.h>
+#include <asm/mach/map.h>
 
 #include <mach/motherboard.h>
 
@@ -19,13 +24,149 @@
 
 extern void versatile_secondary_startup(void);
 
+#if defined(CONFIG_OF)
+
+static enum {
+	UNKNOWN_SCU,
+	GENERIC_SCU,
+	CORTEX_A9_SCU,
+} vexpress_dt_scu = UNKNOWN_SCU;
+
+static void __init vexpress_dt_init_cpu_map(int ncores)
+{
+	int i;
+
+	if (ncores > nr_cpu_ids) {
+		pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
+				ncores, nr_cpu_ids);
+		ncores = nr_cpu_ids;
+	}
+
+	for (i = 0; i < ncores; ++i)
+		set_cpu_possible(i, true);
+}
+
+static struct map_desc vexpress_dt_cortex_a9_scu_map[] __initdata = {
+	{
+		.virtual	= (unsigned long)V2T_PERIPH,
+		/* .pfn	set in vexpress_dt_init_cortex_a9_scu() */
+		.length		= SZ_128,
+		.type		= MT_DEVICE,
+	},
+};
+
+static int __init vexpress_dt_find_scu(unsigned long node,
+		const char *uname, int depth, void *data)
+{
+	if (of_flat_dt_is_compatible(node, "arm,cortex-a9-scu")) {
+		__be32 *reg = of_get_flat_dt_prop(node, "reg", NULL);
+
+		if (WARN_ON(!reg))
+			return -EINVAL;
+
+		vexpress_dt_cortex_a9_scu_map[0].pfn =
+				__phys_to_pfn(be32_to_cpup(reg));
+		iotable_init(vexpress_dt_cortex_a9_scu_map,
+				ARRAY_SIZE(vexpress_dt_cortex_a9_scu_map));
+
+		vexpress_dt_init_cpu_map(scu_get_core_count(V2T_PERIPH));
+		set_smp_cross_call(gic_raise_softirq);
+
+		vexpress_dt_scu = CORTEX_A9_SCU;
+
+		return 1;
+	}
+
+	return 0;
+}
+
+static int __init vexpress_dt_nr_cpus(unsigned long node, const char *uname,
+		int depth, void *data)
+{
+	static int prev_depth = -1;
+	static int nr_cpus = -1;
+
+	if (prev_depth > depth && nr_cpus > 0)
+		return nr_cpus;
+
+	if (nr_cpus < 0 && strcmp(uname, "cpus") == 0)
+		nr_cpus = 0;
+
+	if (nr_cpus >= 0) {
+		const char *device_type = of_get_flat_dt_prop(node,
+				"device_type", NULL);
+
+		if (device_type && strcmp(device_type, "cpu") == 0)
+			nr_cpus++;
+	}
+
+	prev_depth = depth;
+
+	return 0;
+}
+
+static void __init vexpress_dt_smp_init_cpus(void)
+{
+	int res = of_scan_flat_dt(vexpress_dt_find_scu, NULL);
+
+	if (WARN_ON(res < 0))
+		return;
+
+	if (vexpress_dt_scu == UNKNOWN_SCU) {
+		int ncores = of_scan_flat_dt(vexpress_dt_nr_cpus, NULL);
+		if (ncores < 2)
+			return;
+
+		vexpress_dt_scu = GENERIC_SCU;
+
+		vexpress_dt_init_cpu_map(ncores);
+		set_smp_cross_call(gic_raise_softirq);
+	}
+}
+
+static void __init vexpress_dt_smp_prepare_cpus(unsigned int max_cpus)
+{
+	int i;
+
+	switch (vexpress_dt_scu) {
+	case GENERIC_SCU:
+		for (i = 0; i < max_cpus; i++)
+			set_cpu_present(i, true);
+		break;
+	case CORTEX_A9_SCU:
+		scu_enable(V2T_PERIPH);
+		break;
+	default:
+		WARN_ON(1);
+		break;
+	}
+}
+
+#else
+
+static void __init vexpress_dt_smp_init_cpus(void)
+{
+	WARN_ON(1);
+}
+
+void __init vexpress_dt_smp_prepare_cpus(unsigned int max_cpus)
+{
+	WARN_ON(1);
+}
+
+#endif
+
 /*
  * Initialise the CPU possible map early - this describes the CPUs
  * which may be present or become present in the system.
  */
 void __init smp_init_cpus(void)
 {
-	ct_desc->init_cpu_map();
+	if (ct_desc)
+		ct_desc->init_cpu_map();
+	else
+		vexpress_dt_smp_init_cpus();
+
 }
 
 void __init platform_smp_prepare_cpus(unsigned int max_cpus)
@@ -34,7 +175,10 @@ void __init platform_smp_prepare_cpus(unsigned int max_cpus)
 	 * Initialise the present map, which describes the set of CPUs
 	 * actually populated at the present time.
 	 */
-	ct_desc->smp_enable(max_cpus);
+	if (ct_desc)
+		ct_desc->smp_enable(max_cpus);
+	else
+		vexpress_dt_smp_prepare_cpus(max_cpus);
 
 	/*
 	 * Write the address of secondary startup into the
-- 
1.7.5.4