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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2005-11-07 21:05:42 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2005-11-07 21:05:42 +0000
commit862184fe013146a0d9654a5598c5a2691747541c (patch)
tree0f3f0d46c79c7eae3d504c0e1be9ff923f1b2e36 /arch/arm/mach-realview/platsmp.c
parentfea543f47733cc843cd74d95065ed1d4a04b38ed (diff)
[ARM SMP] Add Realview MPcore SMP support
Add SMP support for the MPcore tile fitted to the Realview ARM platform. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-realview/platsmp.c')
-rw-r--r--arch/arm/mach-realview/platsmp.c195
1 files changed, 195 insertions, 0 deletions
diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c
new file mode 100644
index 00000000000..9844644d0fb
--- /dev/null
+++ b/arch/arm/mach-realview/platsmp.c
@@ -0,0 +1,195 @@
+/*
+ * linux/arch/arm/mach-realview/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/smp.h>
+
+#include <asm/cacheflush.h>
+#include <asm/hardware/arm_scu.h>
+#include <asm/hardware.h>
+
+#include "core.h"
+
+extern void realview_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 unsigned int __init get_core_count(void)
+{
+ unsigned int ncores;
+
+ ncores = __raw_readl(IO_ADDRESS(REALVIEW_MPCORE_SCU_BASE) + SCU_CONFIG);
+
+ return (ncores & 0x03) + 1;
+}
+
+static DEFINE_SPINLOCK(boot_lock);
+
+void __cpuinit platform_secondary_init(unsigned int cpu)
+{
+ /*
+ * the primary core may have used a "cross call" soft interrupt
+ * to get this processor out of WFI in the BootMonitor - make
+ * sure that we are no longer being sent this soft interrupt
+ */
+ smp_cross_call_done(cpumask_of_cpu(cpu));
+
+ /*
+ * 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(__io_address(REALVIEW_GIC_CPU_BASE));
+
+ /*
+ * let the primary processor know we're out of the
+ * pen, then head off into the C entry point
+ */
+ pen_release = -1;
+
+ /*
+ * 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);
+
+ /*
+ * The secondary processor is waiting to be released from
+ * the holding pen - release it, then wait for it to flag
+ * that it has been released by resetting pen_release.
+ *
+ * Note that "pen_release" is the hardware CPU ID, whereas
+ * "cpu" is Linux's internal ID.
+ */
+ pen_release = cpu;
+ flush_cache_all();
+
+ /*
+ * XXX
+ *
+ * This is a later addition to the booting protocol: the
+ * bootMonitor now puts secondary cores into WFI, so
+ * poke_milo() no longer gets the cores moving; we need
+ * to send a soft interrupt to wake the secondary core.
+ * Use smp_cross_call() for this, since there's little
+ * point duplicating the code here
+ */
+ smp_cross_call(cpumask_of_cpu(cpu));
+
+ timeout = jiffies + (1 * HZ);
+ while (time_before(jiffies, timeout)) {
+ 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;
+}
+
+static void __init poke_milo(void)
+{
+ extern void secondary_startup(void);
+
+ /* nobody is to be released from the pen yet */
+ pen_release = -1;
+
+ /*
+ * write the address of secondary startup into the system-wide
+ * flags register, then clear the bottom two bits, which is what
+ * BootMonitor is waiting for
+ */
+#if 1
+#define REALVIEW_SYS_FLAGSS_OFFSET 0x30
+ __raw_writel(virt_to_phys(realview_secondary_startup),
+ (IO_ADDRESS(REALVIEW_SYS_BASE) +
+ REALVIEW_SYS_FLAGSS_OFFSET));
+#define REALVIEW_SYS_FLAGSC_OFFSET 0x34
+ __raw_writel(3,
+ (IO_ADDRESS(REALVIEW_SYS_BASE) +
+ REALVIEW_SYS_FLAGSC_OFFSET));
+#endif
+
+ mb();
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+ unsigned int ncores = get_core_count();
+ unsigned int cpu = smp_processor_id();
+ int i;
+
+ /* sanity check */
+ if (ncores == 0) {
+ printk(KERN_ERR
+ "Realview: strange CM count of 0? Default to 1\n");
+
+ ncores = 1;
+ }
+
+ if (ncores > NR_CPUS) {
+ printk(KERN_WARNING
+ "Realview: no. of cores (%d) greater than configured "
+ "maximum of %d - clipping\n",
+ ncores, NR_CPUS);
+ ncores = NR_CPUS;
+ }
+
+ smp_store_cpu_info(cpu);
+
+ /*
+ * are we trying to boot more cores than exist?
+ */
+ if (max_cpus > ncores)
+ max_cpus = ncores;
+
+ /*
+ * Initialise the possible/present maps.
+ * cpu_possible_map describes the set of CPUs which may be present
+ * cpu_present_map describes the set of CPUs populated
+ */
+ for (i = 0; i < max_cpus; i++) {
+ cpu_set(i, cpu_possible_map);
+ cpu_set(i, cpu_present_map);
+ }
+
+ /*
+ * Do we need any more CPUs? If so, then let them know where
+ * to start. Note that, on modern versions of MILO, the "poke"
+ * doesn't actually do anything until each individual core is
+ * sent a soft interrupt to get it out of WFI
+ */
+ if (max_cpus > 1)
+ poke_milo();
+}