sh: Initial SH-X3 SMP support.

This adds basic support for SH-X3 SMP (4 CPUs).

More IPI and cache debugging is necessary, mostly interfacing the
d-cache coherency and the I-cache broadcast invalidates. Only for
testing at present!

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

2 files changed, 125 insertions, 1 deletions

diff --git a/arch/sh/kernel/cpu/sh4a/Makefile b/arch/sh/kernel/cpu/sh4a/Makefile
index e6a1fb5f8484..24539873943a 100644
--- a/arch/sh/kernel/cpu/sh4a/Makefile
+++ b/arch/sh/kernel/cpu/sh4a/Makefile
@@ -10,6 +10,9 @@ obj-$(CONFIG_CPU_SUBTYPE_SH7343)	+= setup-sh7343.o
 obj-$(CONFIG_CPU_SUBTYPE_SH7722)	+= setup-sh7722.o
 obj-$(CONFIG_CPU_SUBTYPE_SHX3)		+= setup-shx3.o
 
+# SMP setup
+smp-$(CONFIG_CPU_SUBTYPE_SHX3)		:= smp-shx3.o
+
 # Primary on-chip clocks (common)
 clock-$(CONFIG_CPU_SUBTYPE_SH7770)	:= clock-sh7770.o
 clock-$(CONFIG_CPU_SUBTYPE_SH7780)	:= clock-sh7780.o
@@ -18,4 +21,5 @@ clock-$(CONFIG_CPU_SUBTYPE_SH7343)	:= clock-sh7343.o
 clock-$(CONFIG_CPU_SUBTYPE_SH7722)	:= clock-sh7722.o
 clock-$(CONFIG_CPU_SUBTYPE_SHX3)	:= clock-shx3.o
 
-obj-y	+= $(clock-y)
+obj-y			+= $(clock-y)
+obj-$(CONFIG_SMP)	+= $(smp-y)
diff --git a/arch/sh/kernel/cpu/sh4a/smp-shx3.c b/arch/sh/kernel/cpu/sh4a/smp-shx3.c
new file mode 100644
index 000000000000..e5e06845fa43
--- /dev/null
+++ b/arch/sh/kernel/cpu/sh4a/smp-shx3.c
@@ -0,0 +1,120 @@
+/*
+ * SH-X3 SMP
+ *
+ *  Copyright (C) 2007  Paul Mundt
+ *  Copyright (C) 2007  Magnus Damm
+ *
+ * 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.
+ */
+#include <linux/init.h>
+#include <linux/cpumask.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+
+void __init plat_smp_setup(void)
+{
+	unsigned int cpu = 0;
+	int i, num;
+
+	cpus_clear(cpu_possible_map);
+	cpu_set(cpu, cpu_possible_map);
+
+	__cpu_number_map[0] = 0;
+	__cpu_logical_map[0] = 0;
+
+	/*
+	 * Do this stupidly for now.. we don't have an easy way to probe
+	 * for the total number of cores.
+	 */
+	for (i = 1, num = 0; i < NR_CPUS; i++) {
+		cpu_set(i, cpu_possible_map);
+		__cpu_number_map[i] = ++num;
+		__cpu_logical_map[num] = i;
+	}
+
+        printk(KERN_INFO "Detected %i available secondary CPU(s)\n", num);
+}
+
+void __init plat_prepare_cpus(unsigned int max_cpus)
+{
+}
+
+#define STBCR_REG(phys_id) (0xfe400004 | (phys_id << 12))
+#define RESET_REG(phys_id) (0xfe400008 | (phys_id << 12))
+
+#define STBCR_MSTP	0x00000001
+#define STBCR_RESET	0x00000002
+#define STBCR_LTSLP	0x80000000
+
+#define STBCR_AP_VAL	(STBCR_RESET | STBCR_LTSLP)
+
+void plat_start_cpu(unsigned int cpu, unsigned long entry_point)
+{
+	ctrl_outl(entry_point, RESET_REG(cpu));
+
+	if (!(ctrl_inl(STBCR_REG(cpu)) & STBCR_MSTP))
+		ctrl_outl(STBCR_MSTP, STBCR_REG(cpu));
+
+	while (!(ctrl_inl(STBCR_REG(cpu)) & STBCR_MSTP))
+		;
+
+	/* Start up secondary processor by sending a reset */
+	ctrl_outl(STBCR_AP_VAL, STBCR_REG(cpu));
+}
+
+int plat_smp_processor_id(void)
+{
+	return ctrl_inl(0xff000048); /* CPIDR */
+}
+
+void plat_send_ipi(unsigned int cpu, unsigned int message)
+{
+	unsigned long addr = 0xfe410070 + (cpu * 4);
+
+	BUG_ON(cpu >= 4);
+	BUG_ON(message >= SMP_MSG_NR);
+
+	ctrl_outl(1 << (message << 2), addr); /* C0INTICI..CnINTICI */
+}
+
+struct ipi_data {
+	void (*handler)(void *);
+	void *arg;
+	unsigned int message;
+};
+
+static irqreturn_t ipi_interrupt_handler(int irq, void *arg)
+{
+	struct ipi_data *id = arg;
+	unsigned int cpu = hard_smp_processor_id();
+	unsigned int offs = 4 * cpu;
+	unsigned int x;
+
+	x = ctrl_inl(0xfe410070 + offs); /* C0INITICI..CnINTICI */
+	x &= (1 << (id->message << 2));
+	ctrl_outl(x, 0xfe410080 + offs); /* C0INTICICLR..CnINTICICLR */
+
+	id->handler(id->arg);
+
+	return IRQ_HANDLED;
+}
+
+static struct ipi_data ipi_handlers[SMP_MSG_NR];
+
+int plat_register_ipi_handler(unsigned int message,
+			      void (*handler)(void *), void *arg)
+{
+	struct ipi_data *id = &ipi_handlers[message];
+
+	BUG_ON(SMP_MSG_NR >= 8);
+	BUG_ON(message >= SMP_MSG_NR);
+
+	id->handler = handler;
+	id->arg = arg;
+	id->message = message;
+
+	return request_irq(104 + message, ipi_interrupt_handler, 0, "IPI", id);
+}