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Message-ID: <1366368468-29143-8-git-send-email-chenhui.zhao@freescale.com>
Date: Fri, 19 Apr 2013 18:47:41 +0800
From: Zhao Chenhui <chenhui.zhao@...escale.com>
To: <linuxppc-dev@...ts.ozlabs.org>
CC: <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 08/15] powerpc/85xx: add cpu hotplug support for e500mc/e5500
From: Chen-Hui Zhao <chenhui.zhao@...escale.com>
Add support to disable and re-enable individual cores at runtime.
This supports e500mc/e5500 core based SoCs.
To prevent the register access race, only read/write RCPM registers
in platform_cpu_die() on the boot cpu instead of accessing by individual
cpus. Platform implementations can override the platform_cpu_die().
Signed-off-by: Zhao Chenhui <chenhui.zhao@...escale.com>
Signed-off-by: Li Yang <leoli@...escale.com>
Signed-off-by: Andy Fleming <afleming@...escale.com>
---
arch/powerpc/Kconfig | 2 +-
arch/powerpc/include/asm/smp.h | 1 +
arch/powerpc/kernel/smp.c | 16 ++++++++++-
arch/powerpc/platforms/85xx/smp.c | 56 ++++++++++++++++++++++++++++++++++--
4 files changed, 69 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 0e11a09..b6851be 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -347,7 +347,7 @@ config SWIOTLB
config HOTPLUG_CPU
bool "Support for enabling/disabling CPUs"
depends on SMP && HOTPLUG && (PPC_PSERIES || \
- PPC_PMAC || PPC_POWERNV || (PPC_85xx && !PPC_E500MC))
+ PPC_PMAC || PPC_POWERNV || PPC_85xx)
---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 195ce2a..95be584 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -60,6 +60,7 @@ extern void smp_generic_take_timebase(void);
DECLARE_PER_CPU(unsigned int, cpu_pvr);
#ifdef CONFIG_HOTPLUG_CPU
+void platform_cpu_die(unsigned int cpu);
extern void migrate_irqs(void);
int generic_cpu_disable(void);
void generic_cpu_die(unsigned int cpu);
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 76bd9da..386c7ea 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -381,14 +381,28 @@ int generic_cpu_disable(void)
return 0;
}
+/**
+ * platform_cpu_die() - do platform related operations on the boot cpu
+ * after CPU_DEAD is assigned to the variable cpu_state of the dying cpu.
+ * Platform implementations can override this.
+ *
+ * @cpu: the cpu to die
+ */
+void __attribute__ ((weak)) platform_cpu_die(unsigned int cpu)
+{
+ return;
+}
+
void generic_cpu_die(unsigned int cpu)
{
int i;
for (i = 0; i < 100; i++) {
smp_rmb();
- if (per_cpu(cpu_state, cpu) == CPU_DEAD)
+ if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
+ platform_cpu_die(cpu);
return;
+ }
msleep(100);
}
printk(KERN_ERR "CPU%d didn't die...\n", cpu);
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c
index 6c2fe6b..6eae2e0 100644
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -40,7 +40,7 @@ struct epapr_spin_table {
u32 pir;
};
-static struct ccsr_guts __iomem *guts;
+static void __iomem *guts_regs;
static u64 timebase;
static int tb_req;
static int tb_valid;
@@ -62,7 +62,7 @@ static inline u32 get_phy_cpu_mask(void)
static void mpc85xx_timebase_freeze(int freeze)
{
- struct ccsr_rcpm __iomem *rcpm = (typeof(rcpm))guts;
+ struct ccsr_rcpm __iomem *rcpm = guts_regs;
u32 mask = get_phy_cpu_mask();
if (freeze)
@@ -76,6 +76,7 @@ static void mpc85xx_timebase_freeze(int freeze)
#else
static void mpc85xx_timebase_freeze(int freeze)
{
+ struct ccsr_guts __iomem *guts = guts_regs;
uint32_t mask;
mask = CCSR_GUTS_DEVDISR_TB0 | CCSR_GUTS_DEVDISR_TB1;
@@ -84,6 +85,7 @@ static void mpc85xx_timebase_freeze(int freeze)
else
clrbits32(&guts->devdisr, mask);
+ /* read back to push the previous write */
in_be32(&guts->devdisr);
}
#endif
@@ -128,7 +130,45 @@ static void mpc85xx_take_timebase(void)
local_irq_restore(flags);
}
+static void core_reset_erratum(int hw_cpu)
+{
+#ifdef CONFIG_PPC_E500MC
+ struct ccsr_rcpm __iomem *rcpm = guts_regs;
+
+ clrbits32(&rcpm->cnapcr, 1 << hw_cpu);
+#endif
+}
+
#ifdef CONFIG_HOTPLUG_CPU
+#ifdef CONFIG_PPC_E500MC
+static void __cpuinit smp_85xx_mach_cpu_die(void)
+{
+ unsigned int cpu = smp_processor_id();
+
+ local_irq_disable();
+ idle_task_exit();
+ mb();
+
+ mtspr(SPRN_TCR, 0);
+
+ __flush_disable_L1();
+ disable_backside_L2_cache();
+
+ generic_set_cpu_dead(cpu);
+
+ while (1);
+}
+
+void platform_cpu_die(unsigned int cpu)
+{
+ unsigned int hw_cpu = get_hard_smp_processor_id(cpu);
+ struct ccsr_rcpm __iomem *rcpm = guts_regs;
+
+ /* Core Nap Operation */
+ setbits32(&rcpm->cnapcr, 1 << hw_cpu);
+}
+#else
+/* for e500v1 and e500v2 */
static void __cpuinit smp_85xx_mach_cpu_die(void)
{
unsigned int cpu = smp_processor_id();
@@ -156,6 +196,7 @@ static void __cpuinit smp_85xx_mach_cpu_die(void)
while (1)
;
}
+#endif /* CONFIG_PPC_E500MC */
#endif
static inline void flush_spin_table(void *spin_table)
@@ -228,6 +269,13 @@ static int __cpuinit smp_85xx_kick_cpu(int nr)
flush_spin_table(spin_table);
/*
+ * Due to an erratum that core hard reset and core warm reset
+ * are unable to wake up cores from power management modes,
+ * wake up cores before reset.
+ */
+ core_reset_erratum(hw_cpu);
+
+ /*
* We don't set the BPTR register here since it already points
* to the boot page properly.
*/
@@ -436,9 +484,9 @@ void __init mpc85xx_smp_init(void)
np = of_find_matching_node(NULL, mpc85xx_smp_guts_ids);
if (np) {
- guts = of_iomap(np, 0);
+ guts_regs = of_iomap(np, 0);
of_node_put(np);
- if (!guts) {
+ if (!guts_regs) {
pr_err("%s: Could not map guts node address\n",
__func__);
return;
--
1.7.3
--
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