Thread (1 message) 1 message, 1 author, 2012-11-21
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[PATCH V6 5/5] arm: mvebu: Add SMP support for Armada XP

From: Gregory CLEMENT <hidden>
Date: 2012-11-21 14:59:30
Also in: linux-arm-kernel
Subsystem: arm port, arm/marvell kirkwood and armada 370, 375, 38x, 39x, xp, 3700, 7k/8k, cn9130 soc support, the rest · Maintainers: Russell King, Andrew Lunn, Gregory Clement, Sebastian Hesselbarth, Linus Torvalds

Possibly related (same subject, not in this thread)

This enables SMP support on the Armada XP processor. It adds the
mandatory functions to support SMP such as: the SMP initialization
functions in platsmp.c, the secondary CPU entry point in headsmp.S and
the CPU hotplug initial support in hotplug.c.

Signed-off-by: Yehuda Yitschak <redacted>
Signed-off-by: Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---
 arch/arm/configs/mvebu_defconfig    |    3 +
 arch/arm/mach-mvebu/Kconfig         |    1 +
 arch/arm/mach-mvebu/Makefile        |    2 +
 arch/arm/mach-mvebu/armada-370-xp.c |    3 +
 arch/arm/mach-mvebu/common.h        |    3 +
 arch/arm/mach-mvebu/headsmp.S       |   49 ++++++++++++++
 arch/arm/mach-mvebu/hotplug.c       |   30 +++++++++
 arch/arm/mach-mvebu/platsmp.c       |  122 +++++++++++++++++++++++++++++++++++
 8 files changed, 213 insertions(+)
 create mode 100644 arch/arm/mach-mvebu/headsmp.S
 create mode 100644 arch/arm/mach-mvebu/hotplug.c
 create mode 100644 arch/arm/mach-mvebu/platsmp.c
diff --git a/arch/arm/configs/mvebu_defconfig b/arch/arm/configs/mvebu_defconfig
index 3458752..da598d3 100644
--- a/arch/arm/configs/mvebu_defconfig
+++ b/arch/arm/configs/mvebu_defconfig
@@ -12,6 +12,9 @@ CONFIG_ARCH_MVEBU=y
 CONFIG_MACH_ARMADA_370=y
 CONFIG_MACH_ARMADA_XP=y
 # CONFIG_CACHE_L2X0 is not set
+# CONFIG_SWP_EMULATE is not set
+CONFIG_SMP=y
+# CONFIG_LOCAL_TIMERS is not set
 CONFIG_AEABI=y
 CONFIG_HIGHMEM=y
 # CONFIG_COMPACTION is not set
diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig
index f4c3bf8..c934e1d 100644
--- a/arch/arm/mach-mvebu/Kconfig
+++ b/arch/arm/mach-mvebu/Kconfig
@@ -21,6 +21,7 @@ menu "Marvell SOC with device tree"
 config MACH_ARMADA_370_XP
 	bool
 	select ARMADA_370_XP_TIMER
+	select HAVE_SMP
 	select CPU_PJ4B
 
 config MACH_ARMADA_370
diff --git a/arch/arm/mach-mvebu/Makefile b/arch/arm/mach-mvebu/Makefile
index 2e3ec11..5dcb369 100644
--- a/arch/arm/mach-mvebu/Makefile
+++ b/arch/arm/mach-mvebu/Makefile
@@ -3,3 +3,5 @@ ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/$(src)/include \
 
 obj-y += system-controller.o
 obj-$(CONFIG_MACH_ARMADA_370_XP) += armada-370-xp.o irq-armada-370-xp.o addr-map.o coherency.o coherency_ll.o pmsu.o
+obj-$(CONFIG_SMP)                += platsmp.o headsmp.o
+obj-$(CONFIG_HOTPLUG_CPU)        += hotplug.o
diff --git a/arch/arm/mach-mvebu/armada-370-xp.c b/arch/arm/mach-mvebu/armada-370-xp.c
index 3292d6d..472e70f 100644
--- a/arch/arm/mach-mvebu/armada-370-xp.c
+++ b/arch/arm/mach-mvebu/armada-370-xp.c
@@ -23,6 +23,7 @@
 #include <asm/mach/time.h>
 #include "armada-370-xp.h"
 #include "common.h"
+#include "coherency.h"
 
 static struct map_desc armada_370_xp_io_desc[] __initdata = {
 	{
@@ -51,6 +52,7 @@ struct sys_timer armada_370_xp_timer = {
 static void __init armada_370_xp_dt_init(void)
 {
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
+	coherency_init();
 }
 
 static const char * const armada_370_xp_dt_board_dt_compat[] = {
@@ -60,6 +62,7 @@ static const char * const armada_370_xp_dt_board_dt_compat[] = {
 };
 
 DT_MACHINE_START(ARMADA_XP_DT, "Marvell Aramada 370/XP (Device Tree)")
+	.smp		= smp_ops(armada_xp_smp_ops),
 	.init_machine	= armada_370_xp_dt_init,
 	.map_io		= armada_370_xp_map_io,
 	.init_irq	= armada_370_xp_init_irq,
diff --git a/arch/arm/mach-mvebu/common.h b/arch/arm/mach-mvebu/common.h
index 9285d04..aa27bc2 100644
--- a/arch/arm/mach-mvebu/common.h
+++ b/arch/arm/mach-mvebu/common.h
@@ -20,6 +20,9 @@ void mvebu_restart(char mode, const char *cmd);
 void armada_370_xp_init_irq(void);
 void armada_370_xp_handle_irq(struct pt_regs *regs);
 
+void armada_xp_cpu_die(unsigned int cpu);
 int armada_370_xp_coherency_init(void);
 int armada_370_xp_pmsu_init(void);
+void armada_xp_secondary_startup(void);
+extern struct smp_operations armada_xp_smp_ops;
 #endif
diff --git a/arch/arm/mach-mvebu/headsmp.S b/arch/arm/mach-mvebu/headsmp.S
new file mode 100644
index 0000000..a06e0ed
--- /dev/null
+++ b/arch/arm/mach-mvebu/headsmp.S
@@ -0,0 +1,49 @@
+/*
+ * SMP support: Entry point for secondary CPUs
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Yehuda Yitschak <yehuday-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>
+ * Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
+ * Thomas Petazzoni <thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * This file implements the assembly entry point for secondary CPUs in
+ * an SMP kernel. The only thing we need to do is to add the CPU to
+ * the coherency fabric by writing to 2 registers. Currently the base
+ * register addresses are hard coded due to the early initialisation
+ * problems.
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+/*
+ * At this stage the secondary CPUs don't have acces yet to the MMU, so
+ * we have to provide physical addresses
+ */
+#define ARMADA_XP_CFB_BASE	     0xD0020200
+
+	__CPUINIT
+
+/*
+ * Armada XP specific entry point for secondary CPUs.
+ * We add the CPU to the coherency fabric and then jump to secondary
+ * startup
+ */
+ENTRY(armada_xp_secondary_startup)
+
+	/* Read CPU id */
+	mrc     p15, 0, r1, c0, c0, 5
+	and     r1, r1, #0xF
+
+	/* Add CPU to coherency fabric */
+	ldr     r0, =ARMADA_XP_CFB_BASE
+
+	bl	ll_set_cpu_coherent
+	b	secondary_startup
+
+ENDPROC(armada_xp_secondary_startup)
diff --git a/arch/arm/mach-mvebu/hotplug.c b/arch/arm/mach-mvebu/hotplug.c
new file mode 100644
index 0000000..b228b6a
--- /dev/null
+++ b/arch/arm/mach-mvebu/hotplug.c
@@ -0,0 +1,30 @@
+/*
+ * Symmetric Multi Processing (SMP) support for Armada XP
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Lior Amsalem <alior-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>
+ * Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
+ * Thomas Petazzoni <thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/smp.h>
+#include <asm/proc-fns.h>
+
+/*
+ * platform-specific code to shutdown a CPU
+ *
+ * Called with IRQs disabled
+ */
+void __ref armada_xp_cpu_die(unsigned int cpu)
+{
+	cpu_do_idle();
+
+	/* We should never return from idle */
+	panic("mvebu: cpu %d unexpectedly exit from shutdown\n", cpu);
+}
diff --git a/arch/arm/mach-mvebu/platsmp.c b/arch/arm/mach-mvebu/platsmp.c
new file mode 100644
index 0000000..fe16aaf
--- /dev/null
+++ b/arch/arm/mach-mvebu/platsmp.c
@@ -0,0 +1,122 @@
+/*
+ * Symmetric Multi Processing (SMP) support for Armada XP
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Lior Amsalem <alior-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>
+ * Yehuda Yitschak <yehuday-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>
+ * Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
+ * Thomas Petazzoni <thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * The Armada XP SoC has 4 ARMv7 PJ4B CPUs running in full HW coherency
+ * This file implements the routines for preparing the SMP infrastructure
+ * and waking up the secondary CPUs
+ */
+
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <asm/cacheflush.h>
+#include <asm/smp_plat.h>
+#include "common.h"
+#include "armada-370-xp.h"
+#include "pmsu.h"
+#include "coherency.h"
+
+void __init set_secondary_cpus_clock(void)
+{
+	int thiscpu;
+	unsigned long rate;
+	struct clk *cpu_clk = NULL;
+	struct device_node *np = NULL;
+
+	thiscpu = smp_processor_id();
+	for_each_node_by_type(np, "cpu") {
+		int err;
+		int cpu;
+
+		err = of_property_read_u32(np, "reg", &cpu);
+		if (WARN_ON(err))
+			return;
+
+		if (cpu == thiscpu) {
+			cpu_clk = of_clk_get(np, 0);
+			break;
+		}
+	}
+	if (WARN_ON(IS_ERR(cpu_clk)))
+		return;
+	clk_prepare_enable(cpu_clk);
+	rate = clk_get_rate(cpu_clk);
+
+	/* set all the other CPU clk to the same rate than the boot CPU */
+	for_each_node_by_type(np, "cpu") {
+		int err;
+		int cpu;
+
+		err = of_property_read_u32(np, "reg", &cpu);
+		if (WARN_ON(err))
+			return;
+
+		if (cpu != thiscpu) {
+			cpu_clk = of_clk_get(np, 0);
+			clk_set_rate(cpu_clk, rate);
+		}
+	}
+}
+
+static void __cpuinit armada_xp_secondary_init(unsigned int cpu)
+{
+	armada_xp_mpic_smp_cpu_init();
+}
+
+static int __cpuinit armada_xp_boot_secondary(unsigned int cpu,
+					      struct task_struct *idle)
+{
+	pr_info("Booting CPU %d\n", cpu);
+
+	armada_xp_boot_cpu(cpu, armada_xp_secondary_startup);
+
+	return 0;
+}
+
+static void __init armada_xp_smp_init_cpus(void)
+{
+	unsigned int i, ncores;
+	ncores = coherency_get_cpu_count();
+
+	/* Limit possible CPUs to defconfig */
+	if (ncores > nr_cpu_ids) {
+		pr_warn("SMP: %d CPUs physically present. Only %d configured.",
+			ncores, nr_cpu_ids);
+		pr_warn("Clipping CPU count to %d\n", nr_cpu_ids);
+		ncores = nr_cpu_ids;
+	}
+
+	for (i = 0; i < ncores; i++)
+		set_cpu_possible(i, true);
+
+	set_smp_cross_call(armada_mpic_send_doorbell);
+}
+
+void __init armada_xp_smp_prepare_cpus(unsigned int max_cpus)
+{
+	set_secondary_cpus_clock();
+	flush_cache_all();
+	set_cpu_coherent(cpu_logical_map(smp_processor_id()), 0);
+}
+
+struct smp_operations armada_xp_smp_ops __initdata = {
+	.smp_init_cpus		= armada_xp_smp_init_cpus,
+	.smp_prepare_cpus	= armada_xp_smp_prepare_cpus,
+	.smp_secondary_init	= armada_xp_secondary_init,
+	.smp_boot_secondary	= armada_xp_boot_secondary,
+#ifdef CONFIG_HOTPLUG_CPU
+	.cpu_die		= armada_xp_cpu_die,
+#endif
+};
-- 
1.7.9.5
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