ARM: Add Versatile Express SMP support

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

5 files changed, 278 insertions, 0 deletions

diff --git a/arch/arm/mach-vexpress/Makefile b/arch/arm/mach-vexpress/Makefile
index 3c5e1609fc4f..1b71b77ade22 100644
--- a/arch/arm/mach-vexpress/Makefile
+++ b/arch/arm/mach-vexpress/Makefile
@@ -4,3 +4,5 @@
 
 obj-y                                   := v2m.o
 obj-$(CONFIG_ARCH_VEXPRESS_CA9X4)       += ct-ca9x4.o
+obj-$(CONFIG_SMP)                       += platsmp.o headsmp.o
+obj-$(CONFIG_LOCAL_TIMERS)              += localtimer.o
diff --git a/arch/arm/mach-vexpress/headsmp.S b/arch/arm/mach-vexpress/headsmp.S
new file mode 100644
index 000000000000..8a78ff68e1ee
--- /dev/null
+++ b/arch/arm/mach-vexpress/headsmp.S
@@ -0,0 +1,39 @@
+/*
+ *  linux/arch/arm/mach-vexpress/headsmp.S
+ *
+ *  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
+
+/*
+ * Versatile Express specific entry point for secondary CPUs.  This
+ * provides a "holding pen" into which all secondary cores are held
+ * until we're ready for them to initialise.
+ */
+ENTRY(vexpress_secondary_startup)
+        mrc     p15, 0, r0, c0, c0, 5
+        and     r0, r0, #15
+        adr     r4, 1f
+        ldmia   r4, {r5, r6}
+        sub     r4, r4, r5
+        add     r6, r6, r4
+pen:    ldr     r7, [r6]
+        cmp     r7, r0
+        bne     pen
+
+        /*
+         * we've been released from the holding pen: secondary_stack
+         * should now contain the SVC stack for this core
+         */
+        b       secondary_startup
+
+1:      .long   .
+        .long   pen_release
diff --git a/arch/arm/mach-vexpress/include/mach/smp.h b/arch/arm/mach-vexpress/include/mach/smp.h
new file mode 100644
index 000000000000..72a9621ed087
--- /dev/null
+++ b/arch/arm/mach-vexpress/include/mach/smp.h
@@ -0,0 +1,21 @@
+#ifndef __MACH_SMP_H
+#define __MACH_SMP_H
+
+#include <asm/hardware/gic.h>
+
+#define hard_smp_processor_id()                         \
+        ({                                              \
+                unsigned int cpunum;                    \
+                __asm__("mrc p15, 0, %0, c0, c0, 5"     \
+                        : "=r" (cpunum));               \
+                cpunum &= 0x0F;                         \
+        })
+
+/*
+ * We use IRQ1 as the IPI
+ */
+static inline void smp_cross_call(const struct cpumask *mask)
+{
+        gic_raise_softirq(mask, 1);
+}
+#endif
diff --git a/arch/arm/mach-vexpress/localtimer.c b/arch/arm/mach-vexpress/localtimer.c
new file mode 100644
index 000000000000..c0e3a59a0bfc
--- /dev/null
+++ b/arch/arm/mach-vexpress/localtimer.c
@@ -0,0 +1,26 @@
+/*
+ *  linux/arch/arm/mach-vexpress/localtimer.c
+ *
+ *  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>
+#include <mach/irqs.h>
+
+/*
+ * Setup the local clock events for a CPU.
+ */
+void __cpuinit local_timer_setup(struct clock_event_device *evt)
+{
+        evt->irq = IRQ_LOCALTIMER;
+        twd_timer_setup(evt);
+}
diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c
new file mode 100644
index 000000000000..670970699ba9
--- /dev/null
+++ b/arch/arm/mach-vexpress/platsmp.c
@@ -0,0 +1,190 @@
+/*
+ *  linux/arch/arm/mach-vexpress/platsmp.c
+ *
+ *  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/jiffies.h>
+#include <linux/smp.h>
+#include <linux/io.h>
+
+#include <asm/cacheflush.h>
+#include <asm/localtimer.h>
+#include <asm/smp_scu.h>
+#include <asm/unified.h>
+
+#include <mach/ct-ca9x4.h>
+#include <mach/motherboard.h>
+#define V2M_PA_CS7 0x10000000
+
+#include "core.h"
+
+extern void vexpress_secondary_startup(void);
+
+/*
+ * control for which core is the next to come out of the secondary
+ * boot "holding pen"
+ */
+volatile int __cpuinitdata pen_release = -1;
+
+static void __iomem *scu_base_addr(void)
+{
+        return MMIO_P2V(A9_MPCORE_SCU);
+}
+
+static DEFINE_SPINLOCK(boot_lock);
+
+void __cpuinit platform_secondary_init(unsigned int cpu)
+{
+        trace_hardirqs_off();
+
+        /*
+         * if any interrupts are already enabled for the primary
+         * core (e.g. timer irq), then they will not have been enabled
+         * for us: do so
+         */
+        gic_cpu_init(0, gic_cpu_base_addr);
+
+        /*
+         * let the primary processor know we're out of the
+         * pen, then head off into the C entry point
+         */
+        pen_release = -1;
+        smp_wmb();
+
+        /*
+         * Synchronise with the boot thread.
+         */
+        spin_lock(&boot_lock);
+        spin_unlock(&boot_lock);
+}
+
+int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+        unsigned long timeout;
+
+        /*
+         * Set synchronisation state between this boot processor
+         * and the secondary one
+         */
+        spin_lock(&boot_lock);
+
+        /*
+         * This is really belt and braces; we hold unintended secondary
+         * CPUs in the holding pen until we're ready for them.  However,
+         * since we haven't sent them a soft interrupt, they shouldn't
+         * be there.
+         */
+        pen_release = cpu;
+        __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
+        outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
+
+        /*
+         * Send the secondary CPU a soft interrupt, thereby causing
+         * the boot monitor to read the system wide flags register,
+         * and branch to the address found there.
+         */
+        smp_cross_call(cpumask_of(cpu));
+
+        timeout = jiffies + (1 * HZ);
+        while (time_before(jiffies, timeout)) {
+                smp_rmb();
+                if (pen_release == -1)
+                        break;
+
+                udelay(10);
+        }
+
+        /*
+         * now the secondary core is starting up let it run its
+         * calibrations, then wait for it to finish
+         */
+        spin_unlock(&boot_lock);
+
+        return pen_release != -1 ? -ENOSYS : 0;
+}
+
+/*
+ * 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)
+{
+        void __iomem *scu_base = scu_base_addr();
+        unsigned int i, ncores;
+
+        ncores = scu_base ? scu_get_core_count(scu_base) : 1;
+
+        /* sanity check */
+        if (ncores == 0) {
+                printk(KERN_ERR
+                       "vexpress: strange CM count of 0? Default to 1\n");
+
+                ncores = 1;
+        }
+
+        if (ncores > NR_CPUS) {
+                printk(KERN_WARNING
+                       "vexpress: no. of cores (%d) greater than configured "
+                       "maximum of %d - clipping\n",
+                       ncores, NR_CPUS);
+                ncores = NR_CPUS;
+        }
+
+        for (i = 0; i < ncores; i++)
+                set_cpu_possible(i, true);
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+        unsigned int ncores = num_possible_cpus();
+        unsigned int cpu = smp_processor_id();
+        int i;
+
+        smp_store_cpu_info(cpu);
+
+        /*
+         * are we trying to boot more cores than exist?
+         */
+        if (max_cpus > ncores)
+                max_cpus = ncores;
+
+        /*
+         * Initialise the present map, which describes the set of CPUs
+         * actually populated at the present time.
+         */
+        for (i = 0; i < max_cpus; i++)
+                set_cpu_present(i, true);
+
+        /*
+         * Initialise the SCU if there are more than one CPU and let
+         * them know where to start.
+         */
+        if (max_cpus > 1) {
+                /*
+                 * Enable the local timer or broadcast device for the
+                 * boot CPU, but only if we have more than one CPU.
+                 */
+                percpu_timer_setup();
+
+                scu_enable(scu_base_addr());
+
+                /*
+                 * Write the address of secondary startup into the
+                 * system-wide flags register. The boot monitor waits
+                 * until it receives a soft interrupt, and then the
+                 * secondary CPU branches to this address.
+                 */
+                writel(~0, MMIO_P2V(V2M_SYS_FLAGSCLR));
+                writel(BSYM(virt_to_phys(vexpress_secondary_startup)),
+                        MMIO_P2V(V2M_SYS_FLAGSSET));
+        }
+}