ARM: mach-shmobile: SMP base support

Add SMP base support for R-Mobile / SH-Mobile processors.

This patch contains all base code to support CONFIG_SMP
regardless of ARCH_SHMOBILE processor type. Both local timer
and CPU hotplug are supported, but no processor specific
code is included.

At this point only the default behavior is in place, so
a single core will always be used even though CONFIG_SMP
is enabled on multicore systems.

The SMP Kconfig entry for arch/arm/Kconfig is excluded from
this patch to simplify merging.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

8 files changed, 194 insertions, 0 deletions

diff --git a/arch/arm/mach-shmobile/Makefile b/arch/arm/mach-shmobile/Makefile
index f5ad0892984d..d4346ddd9121 100644
--- a/arch/arm/mach-shmobile/Makefile
+++ b/arch/arm/mach-shmobile/Makefile
@@ -11,6 +11,11 @@ obj-$(CONFIG_ARCH_SH7377)	+= setup-sh7377.o clock-sh7377.o intc-sh7377.o
 obj-$(CONFIG_ARCH_SH7372)       += setup-sh7372.o clock-sh7372.o intc-sh7372.o
 obj-$(CONFIG_ARCH_SH73A0)       += setup-sh73a0.o clock-sh73a0.o
 
+# SMP objects
+smp-y                           := platsmp.o headsmp.o
+smp-$(CONFIG_HOTPLUG_CPU)       += hotplug.o
+smp-$(CONFIG_LOCAL_TIMERS)      += localtimer.o
+
 # Pinmux setup
 pfc-y                           :=
 pfc-$(CONFIG_ARCH_SH7367)       += pfc-sh7367.o
@@ -26,4 +31,5 @@ obj-$(CONFIG_MACH_AG5EVM)	+= board-ag5evm.o
 obj-$(CONFIG_MACH_MACKEREL)     += board-mackerel.o
 
 # Framework support
+obj-$(CONFIG_SMP)               += $(smp-y)
 obj-$(CONFIG_GENERIC_GPIO)      += $(pfc-y)
diff --git a/arch/arm/mach-shmobile/headsmp.S b/arch/arm/mach-shmobile/headsmp.S
new file mode 100644
index 000000000000..a5c5af1e6bce
--- /dev/null
+++ b/arch/arm/mach-shmobile/headsmp.S
@@ -0,0 +1,26 @@
+/*
+ * SMP support for R-Mobile / SH-Mobile
+ *
+ * Copyright (C) 2010  Magnus Damm
+ * Copyright (C) 2010  Takashi Yoshii
+ *
+ * Based on vexpress, Copyright (c) 2003 ARM Limited, All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+        __INIT
+
+/*
+ * Reset vector for secondary CPUs.
+ * This will be mapped at address 0 by SBAR register.
+ * We need _long_ jump to the physical address.
+ */
+        .align  12
+ENTRY(shmobile_secondary_vector)
+        ldr     pc, 1f
+1:      .long   secondary_startup - CONFIG_PAGE_OFFSET + CONFIG_MEMORY_START
diff --git a/arch/arm/mach-shmobile/hotplug.c b/arch/arm/mach-shmobile/hotplug.c
new file mode 100644
index 000000000000..238a0d97d2d5
--- /dev/null
+++ b/arch/arm/mach-shmobile/hotplug.c
@@ -0,0 +1,41 @@
+/*
+ * SMP support for R-Mobile / SH-Mobile
+ *
+ * Copyright (C) 2010  Magnus Damm
+ *
+ * Based on realview, Copyright (C) 2002 ARM Ltd, All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/smp.h>
+
+int platform_cpu_kill(unsigned int cpu)
+{
+        return 1;
+}
+
+void platform_cpu_die(unsigned int cpu)
+{
+        while (1) {
+                /*
+                 * here's the WFI
+                 */
+                asm(".word      0xe320f003\n"
+                    :
+                    :
+                    : "memory", "cc");
+        }
+}
+
+int platform_cpu_disable(unsigned int cpu)
+{
+        /*
+         * we don't allow CPU 0 to be shutdown (it is still too special
+         * e.g. clock tick interrupts)
+         */
+        return cpu == 0 ? -EPERM : 0;
+}
diff --git a/arch/arm/mach-shmobile/include/mach/common.h b/arch/arm/mach-shmobile/include/mach/common.h
index 15932fd2435e..32822f7556ea 100644
--- a/arch/arm/mach-shmobile/include/mach/common.h
+++ b/arch/arm/mach-shmobile/include/mach/common.h
@@ -3,6 +3,7 @@
 
 extern struct sys_timer shmobile_timer;
 extern void shmobile_setup_console(void);
+extern void shmobile_secondary_vector(void);
 struct clk;
 extern int clk_init(void);
 
diff --git a/arch/arm/mach-shmobile/include/mach/entry-macro-intc.S b/arch/arm/mach-shmobile/include/mach/entry-macro-intc.S
index a285d13c7416..d06d4ba3251e 100644
--- a/arch/arm/mach-shmobile/include/mach/entry-macro-intc.S
+++ b/arch/arm/mach-shmobile/include/mach/entry-macro-intc.S
@@ -17,6 +17,12 @@
 #include <mach/hardware.h>
 #include <mach/irqs.h>
 
+        .macro  test_for_ipi, irqnr, irqstat, base, tmp
+        .endm
+
+        .macro  test_for_ltirq, irqnr, irqstat, base, tmp
+        .endm
+
         .macro  disable_fiq
         .endm
 
diff --git a/arch/arm/mach-shmobile/include/mach/smp.h b/arch/arm/mach-shmobile/include/mach/smp.h
new file mode 100644
index 000000000000..f4a35ff82c67
--- /dev/null
+++ b/arch/arm/mach-shmobile/include/mach/smp.h
@@ -0,0 +1,16 @@
+#ifndef __MACH_SMP_H
+#define __MACH_SMP_H
+
+#include <asm/hardware/gic.h>
+#include <asm/smp_mpidr.h>
+
+/*
+ * We use IRQ1 as the IPI
+ */
+static inline void smp_cross_call(const struct cpumask *mask)
+{
+#if defined(CONFIG_ARM_GIC)
+        gic_raise_softirq(mask, 1);
+#endif
+}
+#endif
diff --git a/arch/arm/mach-shmobile/localtimer.c b/arch/arm/mach-shmobile/localtimer.c
new file mode 100644
index 000000000000..2111c28b724e
--- /dev/null
+++ b/arch/arm/mach-shmobile/localtimer.c
@@ -0,0 +1,25 @@
+/*
+ * SMP support for R-Mobile / SH-Mobile - local timer portion
+ *
+ * Copyright (C) 2010  Magnus Damm
+ *
+ * Based on vexpress, Copyright (C) 2002 ARM Ltd, All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/clockchips.h>
+#include <asm/smp_twd.h>
+#include <asm/localtimer.h>
+
+/*
+ * Setup the local clock events for a CPU.
+ */
+void __cpuinit local_timer_setup(struct clock_event_device *evt)
+{
+        evt->irq = 29;
+        twd_timer_setup(evt);
+}
diff --git a/arch/arm/mach-shmobile/platsmp.c b/arch/arm/mach-shmobile/platsmp.c
new file mode 100644
index 000000000000..b41f5d0650e4
--- /dev/null
+++ b/arch/arm/mach-shmobile/platsmp.c
@@ -0,0 +1,73 @@
+/*
+ * SMP support for R-Mobile / SH-Mobile
+ *
+ * Copyright (C) 2010  Magnus Damm
+ *
+ * Based on vexpress, Copyright (C) 2002 ARM Ltd, All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/smp.h>
+#include <linux/io.h>
+#include <asm/localtimer.h>
+
+static unsigned int __init shmobile_smp_get_core_count(void)
+{
+        return 1;
+}
+
+static void __init shmobile_smp_prepare_cpus(void)
+{
+        /* do nothing for now */
+}
+
+
+void __cpuinit platform_secondary_init(unsigned int cpu)
+{
+        trace_hardirqs_off();
+}
+
+int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+        return -ENOSYS;
+}
+
+void __init smp_init_cpus(void)
+{
+        unsigned int ncores = shmobile_smp_get_core_count();
+        unsigned int i;
+
+        for (i = 0; i < ncores; i++)
+                set_cpu_possible(i, true);
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+        unsigned int ncores = shmobile_smp_get_core_count();
+        unsigned int cpu = smp_processor_id();
+        int i;
+
+        smp_store_cpu_info(cpu);
+
+        if (max_cpus > ncores)
+                max_cpus = ncores;
+
+        for (i = 0; i < max_cpus; i++)
+                set_cpu_present(i, true);
+
+        if (max_cpus > 1) {
+                shmobile_smp_prepare_cpus();
+
+                /*
+                 * Enable the local timer or broadcast device for the
+                 * boot CPU, but only if we have more than one CPU.
+                 */
+                percpu_timer_setup();
+        }
+}