From: marc_gonzalez@sigmadesigns•com (Marc Gonzalez)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v4 1/2] ARM: tango: add HOTPLUG_CPU support
Date: Wed, 29 Jun 2016 14:21:42 +0200 [thread overview]
Message-ID: <5773BD56.5040104@sigmadesigns.com> (raw)
In-Reply-To: <577266AD.8000006@sigmadesigns.com>
cpu_die() and cpu_kill() are implemented in firmware.
Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns•com>
---
New in v4:
o panic() if tango_cpu_die() returns unexpectedly
o timeout after 10 tries in tango_cpu_kill()
---
arch/arm/mach-tango/platsmp.c | 36 ++++++++++++++++++++++++++++++++++++
arch/arm/mach-tango/smc.h | 4 +++-
2 files changed, 39 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mach-tango/platsmp.c b/arch/arm/mach-tango/platsmp.c
index a21f55e000d2..8380699d4fa3 100644
--- a/arch/arm/mach-tango/platsmp.c
+++ b/arch/arm/mach-tango/platsmp.c
@@ -1,3 +1,4 @@
+#include <linux/delay.h>
#include <linux/init.h>
#include <linux/smp.h>
#include "smc.h"
@@ -9,8 +10,43 @@ static int tango_boot_secondary(unsigned int cpu, struct task_struct *idle)
return 0;
}
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * cpu_kill() and cpu_die() run concurrently on different cores.
+ * Firmware will only "kill" a core once it has properly "died".
+ * Try a few times to kill a core before giving up, and sleep
+ * between tries to give that core enough time to die.
+ */
+static int tango_cpu_kill(unsigned int cpu)
+{
+ int i, err;
+
+ for (i = 0; i < 10; ++i) {
+ msleep(10);
+ err = tango_aux_core_kill(cpu);
+ if (!err)
+ return true;
+ }
+
+ return false;
+}
+
+static void tango_cpu_die(unsigned int cpu)
+{
+ while (tango_aux_core_die(cpu) < 0)
+ cpu_relax();
+
+ panic("cpu %d failed to die\n", cpu);
+}
+#else
+#define tango_cpu_kill NULL
+#define tango_cpu_die NULL
+#endif
+
static const struct smp_operations tango_smp_ops __initconst = {
.smp_boot_secondary = tango_boot_secondary,
+ .cpu_kill = tango_cpu_kill,
+ .cpu_die = tango_cpu_die,
};
CPU_METHOD_OF_DECLARE(tango4_smp, "sigma,tango4-smp", &tango_smp_ops);
diff --git a/arch/arm/mach-tango/smc.h b/arch/arm/mach-tango/smc.h
index 7a4af35cc390..3d31f984f44c 100644
--- a/arch/arm/mach-tango/smc.h
+++ b/arch/arm/mach-tango/smc.h
@@ -2,4 +2,6 @@ extern int tango_smc(unsigned int val, unsigned int service);
#define tango_set_l2_control(val) tango_smc(val, 0x102)
#define tango_start_aux_core(val) tango_smc(val, 0x104)
-#define tango_set_aux_boot_addr(val) tango_smc((unsigned int)val, 0x105)
+#define tango_set_aux_boot_addr(val) tango_smc(val, 0x105)
+#define tango_aux_core_die(val) tango_smc(val, 0x121)
+#define tango_aux_core_kill(val) tango_smc(val, 0x122)
--
2.9.0
next prev parent reply other threads:[~2016-06-29 12:21 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-28 11:55 [PATCH v3 0/2] [for arm-soc] mach-tango updates for v4.8 Marc Gonzalez
2016-06-28 11:59 ` [PATCH v3 1/2] ARM: tango: add HOTPLUG_CPU support Marc Gonzalez
2016-06-28 12:30 ` Robin Murphy
2016-06-28 15:04 ` Marc Gonzalez
2016-06-28 15:16 ` Robin Murphy
2016-06-29 12:28 ` Marc Gonzalez
2016-06-29 12:21 ` Marc Gonzalez [this message]
2016-06-28 12:01 ` [PATCH v3 2/2] Update ARM/TANGO section Marc Gonzalez
2016-07-05 12:32 ` [PATCH v3 0/2] [for arm-soc] mach-tango updates for v4.8 Mason
2016-07-06 3:57 ` Olof Johansson
2016-07-06 20:04 ` Arnd Bergmann
2016-07-07 4:45 ` Olof Johansson
2016-07-07 8:50 ` Mason
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