ARM: 5831/1: ARM: U8500 core machine support

Adds core support for the ST-Ericsson U8500
platform. It supports memory mappings, binds to
the existing modules like GIC, SCU, TWD and
local timers and sets up the infrastructure for
the secondary core.

Reviewed-by: Alessandro Rubini <rubini@unipv.it>
Reviewed-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: srinidhi kasagar <srinidhi.kasagar@stericsson.com>
Acked-by: Andrea Gallo <andrea.gallo@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 177 insertions, 0 deletions

diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c
new file mode 100644
index 000000000000..8dfe7ca245d8
--- /dev/null
+++ b/arch/arm/mach-ux500/platsmp.c
@@ -0,0 +1,177 @@
+/*
+ * Copyright (C) 2002 ARM Ltd.
+ * Copyright (C) 2008 STMicroelctronics.
+ * Copyright (C) 2009 ST-Ericsson.
+ * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
+ *
+ * This file is based on arm realview platform
+ *
+ * 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/cacheflush.h>
+#include <asm/localtimer.h>
+#include <asm/smp_scu.h>
+#include <mach/hardware.h>
+
+/*
+ * 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)
+{
+	return scu_get_core_count(__io_address(U8500_SCU_BASE));
+}
+
+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, __io_address(U8500_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.
+	 */
+	pen_release = cpu;
+	flush_cache_all();
+
+	timeout = jiffies + (1 * HZ);
+	while (time_before(jiffies, timeout)) {
+		if (pen_release == -1)
+			break;
+	}
+
+	/*
+	 * 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 wakeup_secondary(void)
+{
+	/* nobody is to be released from the pen yet */
+	pen_release = -1;
+
+	/*
+	 * write the address of secondary startup into the backup ram register
+	 * at offset 0x1FF4, then write the magic number 0xA1FEED01 to the
+	 * backup ram register at offset 0x1FF0, which is what boot rom code
+	 * is waiting for. This would wake up the secondary core from WFE
+	 */
+#define U8500_CPU1_JUMPADDR_OFFSET 0x1FF4
+	__raw_writel(virt_to_phys(u8500_secondary_startup),
+		(void __iomem *)IO_ADDRESS(U8500_BACKUPRAM0_BASE) +
+		U8500_CPU1_JUMPADDR_OFFSET);
+
+#define U8500_CPU1_WAKEMAGIC_OFFSET 0x1FF0
+	__raw_writel(0xA1FEED01,
+		(void __iomem *)IO_ADDRESS(U8500_BACKUPRAM0_BASE) +
+		U8500_CPU1_WAKEMAGIC_OFFSET);
+
+	/* make sure write buffer is drained */
+	mb();
+}
+
+/*
+ * 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)
+{
+	unsigned int i, ncores = get_core_count();
+
+	for (i = 0; i < ncores; i++)
+		set_cpu_possible(i, true);
+}
+
+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
+		       "U8500: strange CM count of 0? Default to 1\n");
+		ncores = 1;
+	}
+
+	if (ncores > num_possible_cpus())	{
+		printk(KERN_WARNING
+		       "U8500: no. of cores (%d) greater than configured "
+		       "maximum of %d - clipping\n",
+		       ncores, num_possible_cpus());
+		ncores = num_possible_cpus();
+	}
+
+	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);
+
+	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(__io_address(U8500_SCU_BASE));
+		wakeup_secondary();
+	}
+}