[PATCH 04/10] [ARM] tegra: SMP support
Olof Johansson
olof at lixom.net
Fri Jun 4 03:10:36 EDT 2010
From: Colin Cross <ccross at android.com>
Signed-off-by: Colin Cross <ccross at android.com>
Signed-off-by: Erik Gilling <konkers at android.com>
Signed-off-by: Olof Johansson <olof at lixom.net>
---
arch/arm/Kconfig | 12 ++-
arch/arm/mach-tegra/Makefile | 2 +
arch/arm/mach-tegra/headsmp.S | 61 +++++++++++++
arch/arm/mach-tegra/hotplug.c | 140 ++++++++++++++++++++++++++++
arch/arm/mach-tegra/include/mach/smp.h | 30 ++++++
arch/arm/mach-tegra/localtimer.c | 25 +++++
arch/arm/mach-tegra/platsmp.c | 156 ++++++++++++++++++++++++++++++++
7 files changed, 422 insertions(+), 4 deletions(-)
create mode 100644 arch/arm/mach-tegra/headsmp.S
create mode 100644 arch/arm/mach-tegra/hotplug.c
create mode 100644 arch/arm/mach-tegra/include/mach/smp.h
create mode 100644 arch/arm/mach-tegra/localtimer.c
create mode 100644 arch/arm/mach-tegra/platsmp.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 92b9572..14453b2 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1107,10 +1107,12 @@ source "kernel/time/Kconfig"
config SMP
bool "Symmetric Multi-Processing (EXPERIMENTAL)"
depends on EXPERIMENTAL && (REALVIEW_EB_ARM11MP || REALVIEW_EB_A9MP ||\
- MACH_REALVIEW_PB11MP || MACH_REALVIEW_PBX || ARCH_OMAP4 || ARCH_U8500)
+ MACH_REALVIEW_PB11MP || MACH_REALVIEW_PBX || ARCH_OMAP4 || \
+ ARCH_U8500 || ARCH_TEGRA)
depends on GENERIC_CLOCKEVENTS
select USE_GENERIC_SMP_HELPERS
- select HAVE_ARM_SCU if (ARCH_REALVIEW || ARCH_OMAP4 || ARCH_U8500)
+ select HAVE_ARM_SCU if (ARCH_REALVIEW || ARCH_OMAP4 || ARCH_U8500 || \
+ ARCH_TEGRA)
help
This enables support for systems with more than one CPU. If you have
a system with only one CPU, like most personal computers, say N. If
@@ -1179,9 +1181,11 @@ config HOTPLUG_CPU
config LOCAL_TIMERS
bool "Use local timer interrupts"
depends on SMP && (REALVIEW_EB_ARM11MP || MACH_REALVIEW_PB11MP || \
- REALVIEW_EB_A9MP || MACH_REALVIEW_PBX || ARCH_OMAP4 || ARCH_U8500)
+ REALVIEW_EB_A9MP || MACH_REALVIEW_PBX || ARCH_OMAP4 || \
+ ARCH_U8500 || ARCH_TEGRA)
default y
- select HAVE_ARM_TWD if (ARCH_REALVIEW || ARCH_OMAP4 || ARCH_U8500)
+ select HAVE_ARM_TWD if (ARCH_REALVIEW || ARCH_OMAP4 || ARCH_U8500 || \
+ ARCH_TEGRA)
help
Enable support for local timers on SMP platforms, rather then the
legacy IPI broadcast method. Local timers allows the system
diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile
index e20546a..f339559 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 0000000..b5349b2
--- /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 0000000..464316c
--- /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 mach_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 0000000..8b42dab
--- /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 0000000..f81ca7c
--- /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 0000000..1c0fd92
--- /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);
+ }
+}
--
1.5.6.5
More information about the linux-arm-kernel
mailing list