[ARM] tegra: SMP support

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Erik Gilling <konkers@android.com>

6 files changed, 414 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile
index e20546ab2f5f..f339559ca161 100644
--- a/arch/arm/mach-tegra/Makefile
+++ b/arch/arm/mach-tegra/Makefile
@@ -3,3 +3,5 @@ obj-y                                   += io.o
 obj-y                                   += irq.o
 obj-y                                   += clock.o
 obj-$(CONFIG_ARCH_TEGRA_2x_SOC)         += tegra2_clocks.o
+obj-$(CONFIG_SMP)                       += platsmp.o localtimer.o headsmp.o
+obj-$(CONFIG_HOTPLUG_CPU)               += hotplug.o
diff --git a/arch/arm/mach-tegra/headsmp.S b/arch/arm/mach-tegra/headsmp.S
new file mode 100644
index 000000000000..b5349b2f13d2
--- /dev/null
+++ b/arch/arm/mach-tegra/headsmp.S
@@ -0,0 +1,61 @@
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+        .section ".text.head", "ax"
+        __CPUINIT
+
+/*
+ * Tegra specific entry point for secondary CPUs.
+ *   The secondary kernel init calls v7_flush_dcache_all before it enables
+ *   the L1; however, the L1 comes out of reset in an undefined state, so
+ *   the clean + invalidate performed by v7_flush_dcache_all causes a bunch
+ *   of cache lines with uninitialized data and uninitialized tags to get
+ *   written out to memory, which does really unpleasant things to the main
+ *   processor.  We fix this by performing an invalidate, rather than a
+ *   clean + invalidate, before jumping into the kernel.
+ */
+ENTRY(v7_invalidate_l1)
+        mov     r0, #0
+        mcr     p15, 2, r0, c0, c0, 0
+        mrc     p15, 1, r0, c0, c0, 0
+
+        ldr     r1, =0x7fff
+        and     r2, r1, r0, lsr #13
+
+        ldr     r1, =0x3ff
+
+        and     r3, r1, r0, lsr #3  @ NumWays - 1
+        add     r2, r2, #1          @ NumSets
+
+        and     r0, r0, #0x7
+        add     r0, r0, #4          @ SetShift
+
+        clz     r1, r3              @ WayShift
+        add     r4, r3, #1          @ NumWays
+1:      sub     r2, r2, #1          @ NumSets--
+        mov     r3, r4              @ Temp = NumWays
+2:      subs    r3, r3, #1          @ Temp--
+        mov     r5, r3, lsl r1
+        mov     r6, r2, lsl r0
+        orr     r5, r5, r6          @ Reg = (Temp<<WayShift)|(NumSets<<SetShift)
+        mcr     p15, 0, r5, c7, c6, 2
+        bgt     2b
+        cmp     r2, #0
+        bgt     1b
+        dsb
+        isb
+        mov     pc, lr
+ENDPROC(v7_invalidate_l1)
+
+ENTRY(tegra_secondary_startup)
+        msr     cpsr_fsxc, #0xd3
+        bl      v7_invalidate_l1
+        mrc     p15, 0, r0, c0, c0, 5
+        and     r0, r0, #15
+        ldr     r1, =0x6000f100
+        str     r0, [r1]
+1:      ldr     r2, [r1]
+        cmp     r0, r2
+        beq     1b
+        b       secondary_startup
+ENDPROC(tegra_secondary_startup)
diff --git a/arch/arm/mach-tegra/hotplug.c b/arch/arm/mach-tegra/hotplug.c
new file mode 100644
index 000000000000..8e7f115aa21e
--- /dev/null
+++ b/arch/arm/mach-tegra/hotplug.c
@@ -0,0 +1,140 @@
+/*
+ *  linux/arch/arm/mach-realview/hotplug.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/kernel.h>
+#include <linux/errno.h>
+#include <linux/smp.h>
+#include <linux/completion.h>
+
+#include <asm/cacheflush.h>
+
+static DECLARE_COMPLETION(cpu_killed);
+
+static inline void cpu_enter_lowpower(void)
+{
+        unsigned int v;
+
+        flush_cache_all();
+        asm volatile(
+        "       mcr     p15, 0, %1, c7, c5, 0\n"
+        "       mcr     p15, 0, %1, c7, c10, 4\n"
+        /*
+         * Turn off coherency
+         */
+        "       mrc     p15, 0, %0, c1, c0, 1\n"
+        "       bic     %0, %0, #0x20\n"
+        "       mcr     p15, 0, %0, c1, c0, 1\n"
+        "       mrc     p15, 0, %0, c1, c0, 0\n"
+        "       bic     %0, %0, #0x04\n"
+        "       mcr     p15, 0, %0, c1, c0, 0\n"
+          : "=&r" (v)
+          : "r" (0)
+          : "cc");
+}
+
+static inline void cpu_leave_lowpower(void)
+{
+        unsigned int v;
+
+        asm volatile(
+        "mrc    p15, 0, %0, c1, c0, 0\n"
+        "       orr     %0, %0, #0x04\n"
+        "       mcr     p15, 0, %0, c1, c0, 0\n"
+        "       mrc     p15, 0, %0, c1, c0, 1\n"
+        "       orr     %0, %0, #0x20\n"
+        "       mcr     p15, 0, %0, c1, c0, 1\n"
+          : "=&r" (v)
+          :
+          : "cc");
+}
+
+static inline void platform_do_lowpower(unsigned int cpu)
+{
+        /*
+         * there is no power-control hardware on this platform, so all
+         * we can do is put the core into WFI; this is safe as the calling
+         * code will have already disabled interrupts
+         */
+        for (;;) {
+                /*
+                 * here's the WFI
+                 */
+                asm(".word      0xe320f003\n"
+                    :
+                    :
+                    : "memory", "cc");
+
+                /*if (pen_release == cpu) {*/
+                        /*
+                         * OK, proper wakeup, we're done
+                         */
+                        break;
+                /*}*/
+
+                /*
+                 * getting here, means that we have come out of WFI without
+                 * having been woken up - this shouldn't happen
+                 *
+                 * The trouble is, letting people know about this is not really
+                 * possible, since we are currently running incoherently, and
+                 * therefore cannot safely call printk() or anything else
+                 */
+#ifdef DEBUG
+                printk(KERN_WARN "CPU%u: spurious wakeup call\n", cpu);
+#endif
+        }
+}
+
+int platform_cpu_kill(unsigned int cpu)
+{
+        return wait_for_completion_timeout(&cpu_killed, 5000);
+}
+
+/*
+ * platform-specific code to shutdown a CPU
+ *
+ * Called with IRQs disabled
+ */
+void platform_cpu_die(unsigned int cpu)
+{
+#ifdef DEBUG
+        unsigned int this_cpu = hard_smp_processor_id();
+
+        if (cpu != this_cpu) {
+                printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n",
+                           this_cpu, cpu);
+                BUG();
+        }
+#endif
+
+        printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
+        complete(&cpu_killed);
+
+        /*
+         * we're ready for shutdown now, so do it
+         */
+        cpu_enter_lowpower();
+        platform_do_lowpower(cpu);
+
+        /*
+         * bring this CPU back into the world of cache
+         * coherency, and then restore interrupts
+         */
+        cpu_leave_lowpower();
+}
+
+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-tegra/include/mach/smp.h b/arch/arm/mach-tegra/include/mach/smp.h
new file mode 100644
index 000000000000..8b42dab79a70
--- /dev/null
+++ b/arch/arm/mach-tegra/include/mach/smp.h
@@ -0,0 +1,30 @@
+#ifndef ASMARM_ARCH_SMP_H
+#define ASMARM_ARCH_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);
+}
+
+/*
+ * Do nothing on MPcore.
+ */
+static inline void smp_cross_call_done(cpumask_t callmap)
+{
+}
+
+#endif
diff --git a/arch/arm/mach-tegra/localtimer.c b/arch/arm/mach-tegra/localtimer.c
new file mode 100644
index 000000000000..f81ca7cbbc1f
--- /dev/null
+++ b/arch/arm/mach-tegra/localtimer.c
@@ -0,0 +1,25 @@
+/*
+ *  arch/arm/mach-tegra/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/irq.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 = IRQ_LOCALTIMER;
+        twd_timer_setup(evt);
+}
diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c
new file mode 100644
index 000000000000..1c0fd92cab39
--- /dev/null
+++ b/arch/arm/mach-tegra/platsmp.c
@@ -0,0 +1,156 @@
+/*
+ *  linux/arch/arm/mach-tegra/platsmp.c
+ *
+ *  Copyright (C) 2002 ARM Ltd.
+ *  All Rights Reserved
+ *
+ *  Copyright (C) 2009 Palm
+ *  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 <mach/hardware.h>
+#include <asm/mach-types.h>
+#include <asm/localtimer.h>
+#include <asm/smp_scu.h>
+
+#include <mach/iomap.h>
+
+extern void tegra_secondary_startup(void);
+
+static DEFINE_SPINLOCK(boot_lock);
+static void __iomem *scu_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE);
+
+#define EVP_CPU_RESET_VECTOR \
+        (IO_ADDRESS(TEGRA_EXCEPTION_VECTORS_BASE) + 0x100)
+#define CLK_RST_CONTROLLER_CLK_CPU_CMPLX \
+        (IO_ADDRESS(TEGRA_CLK_RESET_BASE) + 0x4c)
+#define CLK_RST_CONTROLLER_RST_CPU_CMPLX_CLR \
+        (IO_ADDRESS(TEGRA_CLK_RESET_BASE) + 0x344)
+
+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(TEGRA_ARM_PERIF_BASE) + 0x100);
+
+        /*
+         * 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 old_boot_vector;
+        unsigned long boot_vector;
+        unsigned long timeout;
+        u32 reg;
+
+        /*
+         * set synchronisation state between this boot processor
+         * and the secondary one
+         */
+        spin_lock(&boot_lock);
+
+
+        /* set the reset vector to point to the secondary_startup routine */
+
+        boot_vector = virt_to_phys(tegra_secondary_startup);
+        old_boot_vector = readl(EVP_CPU_RESET_VECTOR);
+        writel(boot_vector, EVP_CPU_RESET_VECTOR);
+
+        /* enable cpu clock on cpu1 */
+        reg = readl(CLK_RST_CONTROLLER_CLK_CPU_CMPLX);
+        writel(reg & ~(1<<9), CLK_RST_CONTROLLER_CLK_CPU_CMPLX);
+
+        reg = (1<<13) | (1<<9) | (1<<5) | (1<<1);
+        writel(reg, CLK_RST_CONTROLLER_RST_CPU_CMPLX_CLR);
+
+        smp_wmb();
+        flush_cache_all();
+
+        /* unhalt the cpu */
+        writel(0, IO_ADDRESS(TEGRA_FLOW_CTRL_BASE) + 0x14);
+
+        timeout = jiffies + (1 * HZ);
+        while (time_before(jiffies, timeout)) {
+                if (readl(EVP_CPU_RESET_VECTOR) != boot_vector)
+                        break;
+                udelay(10);
+        }
+
+        /* put the old boot vector back */
+        writel(old_boot_vector, EVP_CPU_RESET_VECTOR);
+
+        /*
+         * now the secondary core is starting up let it run its
+         * calibrations, then wait for it to finish
+         */
+        spin_unlock(&boot_lock);
+
+        return 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)
+{
+        unsigned int i, ncores = scu_get_core_count(scu_base);
+
+        for (i = 0; i < ncores; i++)
+                cpu_set(i, cpu_possible_map);
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+        unsigned int ncores = scu_get_core_count(scu_base);
+        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. 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) {
+                percpu_timer_setup();
+                scu_enable(scu_base);
+        }
+}