From: Chenhui Zhao <chenhui.zhao@freescale.com>
To: <linuxppc-dev@lists.ozlabs.org>, <scottwood@freescale.com>
CC: <linux-kernel@vger.kernel.org>, <Jason.Jin@freescale.com>
Subject: [PATCH v2,4/5] PowerPC/mpc85xx: Add hotplug support on E5500 and E500MC cores
Date: Wed, 26 Aug 2015 20:09:47 +0800
Message-ID: <1440590988-25594-4-git-send-email-chenhui.zhao@freescale.com>
In-Reply-To: <1440590988-25594-1-git-send-email-chenhui.zhao@freescale.com>
References: <1440590988-25594-1-git-send-email-chenhui.zhao@freescale.com>
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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>
---
major changes for v2:
* factor out smp_85xx_start_cpu()
* move fsl_rcpm_init() into mpc85xx_smp_init() due to the init sequence
* add hard_irq_disable() after local_irq_save(). for platforms that
  implement lazy enabling/disabling of interrupts, call hard_irq_disable()
  to ensure interrupts are disabled physically.

 arch/powerpc/Kconfig              |   2 +-
 arch/powerpc/include/asm/smp.h    |   3 +
 arch/powerpc/kernel/smp.c         |   7 +-
 arch/powerpc/platforms/85xx/smp.c | 193 ++++++++++++++++++++++----------------
 arch/powerpc/platforms/85xx/smp.h |   1 +
 5 files changed, 122 insertions(+), 84 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..4ff5b71 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -67,6 +67,9 @@ 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 check_cpu_dead(unsigned int cpu);
+#else
+#define generic_set_cpu_up(i)	do { } while (0)
 #endif
 
 #ifdef CONFIG_PPC64
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index ec9ec20..95111f2 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -427,7 +427,7 @@ void generic_cpu_die(unsigned int cpu)
 
 	for (i = 0; i < 100; i++) {
 		smp_rmb();
-		if (per_cpu(cpu_state, cpu) == CPU_DEAD)
+		if (check_cpu_dead(cpu))
 			return;
 		msleep(100);
 	}
@@ -454,6 +454,11 @@ int generic_check_cpu_restart(unsigned int cpu)
 	return per_cpu(cpu_state, cpu) == CPU_UP_PREPARE;
 }
 
+int 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 f9552b8..73eb994 100644
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -10,6 +10,8 @@
  * option) any later version.
  */
 
+#define pr_fmt(fmt) "smp: %s: " fmt, __func__
+
 #include <linux/stddef.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
@@ -52,6 +54,7 @@ static void mpc85xx_give_timebase(void)
 	unsigned long flags;
 
 	local_irq_save(flags);
+	hard_irq_disable();
 
 	while (!tb_req)
 		barrier();
@@ -100,6 +103,7 @@ static void mpc85xx_take_timebase(void)
 	unsigned long flags;
 
 	local_irq_save(flags);
+	hard_irq_disable();
 
 	tb_req = 1;
 	while (!tb_valid)
@@ -135,8 +139,31 @@ static void smp_85xx_mach_cpu_die(void)
 	while (1)
 		;
 }
+
+static void qoriq_cpu_kill(unsigned int cpu)
+{
+	int i;
+
+	for (i = 0; i < 500; i++) {
+		if (check_cpu_dead(cpu)) {
+#ifdef CONFIG_PPC64
+			paca[cpu].cpu_start = 0;
+#endif
+			return;
+		}
+		msleep(20);
+	}
+	pr_err("CPU%d didn't die...\n", cpu);
+}
 #endif
 
+/*
+ * To keep it compatible with old boot program which uses
+ * cache-inhibit spin table, we need to flush the cache
+ * before accessing spin table to invalidate any staled data.
+ * We also need to flush the cache after writing to spin
+ * table to push data out.
+ */
 static inline void flush_spin_table(void *spin_table)
 {
 	flush_dcache_range((ulong)spin_table,
@@ -168,51 +195,20 @@ static void wake_hw_thread(void *info)
 }
 #endif
 
-static int smp_85xx_kick_cpu(int nr)
+static int smp_85xx_start_cpu(int cpu)
 {
-	unsigned long flags;
-	const u64 *cpu_rel_addr;
-	__iomem struct epapr_spin_table *spin_table;
+	int ret = 0;
 	struct device_node *np;
-	int hw_cpu = get_hard_smp_processor_id(nr);
+	const u64 *cpu_rel_addr;
+	unsigned long flags;
 	int ioremappable;
-	int ret = 0;
-
-	WARN_ON(nr < 0 || nr >= NR_CPUS);
-	WARN_ON(hw_cpu < 0 || hw_cpu >= NR_CPUS);
-
-	pr_debug("smp_85xx_kick_cpu: kick CPU #%d\n", nr);
-
-#ifdef CONFIG_PPC64
-	/* Threads don't use the spin table */
-	if (cpu_thread_in_core(nr) != 0) {
-		int primary = cpu_first_thread_sibling(nr);
-
-		if (WARN_ON_ONCE(!cpu_has_feature(CPU_FTR_SMT)))
-			return -ENOENT;
-
-		if (cpu_thread_in_core(nr) != 1) {
-			pr_err("%s: cpu %d: invalid hw thread %d\n",
-			       __func__, nr, cpu_thread_in_core(nr));
-			return -ENOENT;
-		}
+	int hw_cpu = get_hard_smp_processor_id(cpu);
+	struct epapr_spin_table __iomem *spin_table;
 
-		if (!cpu_online(primary)) {
-			pr_err("%s: cpu %d: primary %d not online\n",
-			       __func__, nr, primary);
-			return -ENOENT;
-		}
-
-		smp_call_function_single(primary, wake_hw_thread, &nr, 0);
-		return 0;
-	}
-#endif
-
-	np = of_get_cpu_node(nr, NULL);
+	np = of_get_cpu_node(cpu, NULL);
 	cpu_rel_addr = of_get_property(np, "cpu-release-addr", NULL);
-
-	if (cpu_rel_addr == NULL) {
-		printk(KERN_ERR "No cpu-release-addr for cpu %d\n", nr);
+	if (!cpu_rel_addr) {
+		pr_err("No cpu-release-addr for cpu %d\n", cpu);
 		return -ENOENT;
 	}
 
@@ -232,28 +228,18 @@ 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);
+	hard_irq_disable();
 
-	if (system_state == SYSTEM_RUNNING) {
-		/*
-		 * To keep it compatible with old boot program which uses
-		 * cache-inhibit spin table, we need to flush the cache
-		 * before accessing spin table to invalidate any staled data.
-		 * We also need to flush the cache after writing to spin
-		 * table to push data out.
-		 */
-		flush_spin_table(spin_table);
-		out_be32(&spin_table->addr_l, 0);
-		flush_spin_table(spin_table);
+	if (qoriq_pm_ops)
+		qoriq_pm_ops->cpu_up_prepare(cpu);
 
+	/* if cpu is not spinning, reset it */
+	if (read_spin_table_addr_l(spin_table) != 1) {
 		/*
 		 * We don't set the BPTR register here since it already points
 		 * to the boot page properly.
 		 */
-		mpic_reset_core(nr);
+		mpic_reset_core(cpu);
 
 		/*
 		 * wait until core is ready...
@@ -263,40 +249,23 @@ static int smp_85xx_kick_cpu(int nr)
 		if (!spin_event_timeout(
 				read_spin_table_addr_l(spin_table) == 1,
 				10000, 100)) {
-			pr_err("%s: timeout waiting for core %d to reset\n",
-							__func__, hw_cpu);
-			ret = -ENOENT;
-			goto out;
+			pr_err("timeout waiting for cpu %d to reset\n",
+				hw_cpu);
+			ret = -EAGAIN;
+			goto err;
 		}
-
-		/*  clear the acknowledge status */
-		__secondary_hold_acknowledge = -1;
 	}
-#endif
-	flush_spin_table(spin_table);
-	out_be32(&spin_table->pir, hw_cpu);
-	out_be32(&spin_table->addr_l, __pa(__early_start));
-	flush_spin_table(spin_table);
-
-	/* Wait a bit for the CPU to ack. */
-	if (!spin_event_timeout(__secondary_hold_acknowledge == hw_cpu,
-					10000, 100)) {
-		pr_err("%s: timeout waiting for core %d to ack\n",
-						__func__, hw_cpu);
-		ret = -ENOENT;
-		goto out;
-	}
-out:
-#else
-	smp_generic_kick_cpu(nr);
 
 	flush_spin_table(spin_table);
 	out_be32(&spin_table->pir, hw_cpu);
+#ifdef CONFIG_PPC64
 	out_be64((u64 *)(&spin_table->addr_h),
 		__pa(ppc_function_entry(generic_secondary_smp_init)));
-	flush_spin_table(spin_table);
+#else
+	out_be32(&spin_table->addr_l, __pa(__early_start));
 #endif
-
+	flush_spin_table(spin_table);
+err:
 	local_irq_restore(flags);
 
 	if (ioremappable)
@@ -305,6 +274,61 @@ out:
 	return ret;
 }
 
+static int smp_85xx_kick_cpu(int nr)
+{
+	int ret = 0;
+#ifdef CONFIG_PPC64
+	int primary = nr;
+	int primary_hw = get_hard_smp_processor_id(primary);
+#endif
+
+	WARN_ON(nr < 0 || nr >= num_possible_cpus());
+
+	pr_debug("kick CPU #%d\n", nr);
+
+#ifdef CONFIG_PPC64
+	/* Threads don't use the spin table */
+	if (cpu_thread_in_core(nr) != 0) {
+		int primary = cpu_first_thread_sibling(nr);
+
+		if (WARN_ON_ONCE(!cpu_has_feature(CPU_FTR_SMT)))
+			return -ENOENT;
+
+		if (cpu_thread_in_core(nr) != 1) {
+			pr_err("%s: cpu %d: invalid hw thread %d\n",
+			       __func__, nr, cpu_thread_in_core(nr));
+			return -ENOENT;
+		}
+
+		if (!cpu_online(primary)) {
+			pr_err("%s: cpu %d: primary %d not online\n",
+			       __func__, nr, primary);
+			return -ENOENT;
+		}
+
+		smp_call_function_single(primary, wake_hw_thread, &nr, 0);
+		return 0;
+	}
+
+	ret = smp_85xx_start_cpu(primary);
+	if (ret)
+		return ret;
+
+	paca[nr].cpu_start = 1;
+	generic_set_cpu_up(nr);
+
+	return ret;
+#else
+	ret = smp_85xx_start_cpu(nr);
+	if (ret)
+		return ret;
+
+	generic_set_cpu_up(nr);
+
+	return ret;
+#endif
+}
+
 struct smp_ops_t smp_85xx_ops = {
 	.kick_cpu = smp_85xx_kick_cpu,
 	.cpu_bootable = smp_generic_cpu_bootable,
@@ -402,6 +426,10 @@ void __init mpc85xx_smp_init(void)
 	}
 
 #ifdef CONFIG_HOTPLUG_CPU
+#ifdef CONFIG_FSL_CORENET_RCPM
+	fsl_rcpm_init();
+#endif
+
 #ifdef CONFIG_FSL_PMC
 	mpc85xx_setup_pmc();
 #endif
@@ -409,6 +437,7 @@ void __init mpc85xx_smp_init(void)
 		smp_85xx_ops.give_timebase = mpc85xx_give_timebase;
 		smp_85xx_ops.take_timebase = mpc85xx_take_timebase;
 		ppc_md.cpu_die = smp_85xx_mach_cpu_die;
+		smp_85xx_ops.cpu_die = qoriq_cpu_kill;
 	}
 #endif
 	smp_ops = &smp_85xx_ops;
diff --git a/arch/powerpc/platforms/85xx/smp.h b/arch/powerpc/platforms/85xx/smp.h
index 0b20ae3..8ee19a3 100644
--- a/arch/powerpc/platforms/85xx/smp.h
+++ b/arch/powerpc/platforms/85xx/smp.h
@@ -6,6 +6,7 @@
 #ifdef CONFIG_SMP
 void __init mpc85xx_smp_init(void);
 int __init mpc85xx_setup_pmc(void);
+int __init fsl_rcpm_init(void);
 #else
 static inline void mpc85xx_smp_init(void)
 {
-- 
1.9.1

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