From: <b29983@freescale.com>
To: <b07421@freescale.com>
CC: <linux-kernel@vger.kernel.org>,
        Tang Yuantian <Yuantian.Tang@freescale.com>,
        Chenhui Zhao <chenhui.zhao@freescale.com>,
        Tang Yuantian <Yuantian.Tang@feescale.com>
Subject: [PATCH 2/3] PowerPC/mpc85xx: Add hotplug support on E5500 and E500MC cores
Date: Fri, 31 Jul 2015 17:20:43 +0800
Message-ID: <1438334444-31919-2-git-send-email-b29983@freescale.com>
In-Reply-To: <1438334444-31919-1-git-send-email-b29983@freescale.com>
References: <1438334444-31919-1-git-send-email-b29983@freescale.com>
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From: Tang Yuantian <Yuantian.Tang@freescale.com>

Freescale E500MC and E5500 core-based platforms, like P4080, T1040,
support disabling/enabling CPU dynamically.
This patch adds this feature on those platforms.

Signed-off-by: Chenhui Zhao <chenhui.zhao@freescale.com>
Signed-off-by: Tang Yuantian <Yuantian.Tang@feescale.com>
---
 arch/powerpc/Kconfig              |  2 +-
 arch/powerpc/include/asm/smp.h    |  1 +
 arch/powerpc/kernel/smp.c         |  5 +++++
 arch/powerpc/platforms/85xx/smp.c | 39 ++++++++++++++++++++++++++++++++-------
 4 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 5ef2711..dd9e252 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -386,7 +386,7 @@ config SWIOTLB
 config HOTPLUG_CPU
 	bool "Support for enabling/disabling CPUs"
 	depends on SMP && (PPC_PSERIES || \
-	PPC_PMAC || PPC_POWERNV || (PPC_85xx && !PPC_E500MC))
+	PPC_PMAC || PPC_POWERNV || FSL_SOC_BOOKE)
 	---help---
 	  Say Y here to be able to disable and re-enable individual
 	  CPUs at runtime on SMP machines.
diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index 825663c..bf37d17 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -67,6 +67,7 @@ void generic_cpu_die(unsigned int cpu);
 void generic_set_cpu_dead(unsigned int cpu);
 void generic_set_cpu_up(unsigned int cpu);
 int generic_check_cpu_restart(unsigned int cpu);
+int generic_check_cpu_dead(unsigned int cpu);
 #endif
 
 #ifdef CONFIG_PPC64
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index ec9ec20..2cca27a 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -454,6 +454,11 @@ int generic_check_cpu_restart(unsigned int cpu)
 	return per_cpu(cpu_state, cpu) == CPU_UP_PREPARE;
 }
 
+int generic_check_cpu_dead(unsigned int cpu)
+{
+	return per_cpu(cpu_state, cpu) == CPU_DEAD;
+}
+
 static bool secondaries_inhibited(void)
 {
 	return kvm_hv_mode_active();
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c
index 6811a5b..7f0dadb 100644
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -42,6 +42,7 @@ struct epapr_spin_table {
 	u32	pir;
 };
 
+#ifdef CONFIG_HOTPLUG_CPU
 static u64 timebase;
 static int tb_req;
 static int tb_valid;
@@ -111,7 +112,7 @@ static void mpc85xx_take_timebase(void)
 	local_irq_restore(flags);
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
+#ifndef CONFIG_PPC_E500MC
 static void e500_cpu_idle(void)
 {
 	u32 tmp;
@@ -127,6 +128,7 @@ static void e500_cpu_idle(void)
 	mtmsr(tmp);
 	isync();
 }
+#endif
 
 static void qoriq_cpu_dying(void)
 {
@@ -144,11 +146,30 @@ static void qoriq_cpu_dying(void)
 
 	generic_set_cpu_dead(cpu);
 
+#ifndef CONFIG_PPC_E500MC
 	e500_cpu_idle();
+#endif
 
 	while (1)
 		;
 }
+
+static void qoriq_real_cpu_die(unsigned int cpu)
+{
+	int i;
+
+	for (i = 0; i < 50000; i++) {
+		if (generic_check_cpu_dead(cpu)) {
+			qoriq_pm_ops->cpu_die(cpu);
+#ifdef CONFIG_PPC64
+			paca[cpu].cpu_start = 0;
+#endif
+			return;
+		}
+		udelay(10);
+	}
+	pr_err("%s: CPU%d didn't die...\n", __func__, cpu);
+}
 #endif
 
 static inline void flush_spin_table(void *spin_table)
@@ -246,11 +267,7 @@ static int smp_85xx_kick_cpu(int nr)
 		spin_table = phys_to_virt(*cpu_rel_addr);
 
 	local_irq_save(flags);
-#ifdef CONFIG_PPC32
 #ifdef CONFIG_HOTPLUG_CPU
-	/* Corresponding to generic_set_cpu_dead() */
-	generic_set_cpu_up(nr);
-
 	if (system_state == SYSTEM_RUNNING) {
 		/*
 		 * To keep it compatible with old boot program which uses
@@ -263,6 +280,7 @@ static int smp_85xx_kick_cpu(int nr)
 		out_be32(&spin_table->addr_l, 0);
 		flush_spin_table(spin_table);
 
+		qoriq_pm_ops->cpu_up(nr);
 		/*
 		 * We don't set the BPTR register here since it already points
 		 * to the boot page properly.
@@ -286,7 +304,12 @@ static int smp_85xx_kick_cpu(int nr)
 		/*  clear the acknowledge status */
 		__secondary_hold_acknowledge = -1;
 	}
+
+	/* Corresponding to generic_set_cpu_dead() */
+	generic_set_cpu_up(nr);
 #endif
+
+#ifdef CONFIG_PPC32
 	flush_spin_table(spin_table);
 	out_be32(&spin_table->pir, hw_cpu);
 	out_be32(&spin_table->addr_l, __pa(__early_start));
@@ -300,7 +323,6 @@ static int smp_85xx_kick_cpu(int nr)
 		ret = -ENOENT;
 		goto out;
 	}
-out:
 #else
 	smp_generic_kick_cpu(nr);
 
@@ -311,6 +333,9 @@ out:
 	flush_spin_table(spin_table);
 #endif
 
+#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PPC32)
+out:
+#endif
 	local_irq_restore(flags);
 
 	if (ioremappable)
@@ -324,7 +349,7 @@ struct smp_ops_t smp_85xx_ops = {
 	.cpu_bootable = smp_generic_cpu_bootable,
 #ifdef CONFIG_HOTPLUG_CPU
 	.cpu_disable	= generic_cpu_disable,
-	.cpu_die	= generic_cpu_die,
+	.cpu_die	= qoriq_real_cpu_die,
 #endif
 #if defined(CONFIG_KEXEC) || defined(CONFIG_HOTPLUG_CPU)
 	.give_timebase	= mpc85xx_give_timebase,
-- 
2.1.0.27.g96db324

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