From: Stephen Boyd <sboyd@codeaurora.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
linux-arm-msm@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
John Stultz <john.stultz@linaro.org>,
linux-kernel@vger.kernel.org
Subject: [PATCHv3 01/10] clocksource: add generic dummy timer driver
Date: Wed, 13 Mar 2013 11:17:47 -0700 [thread overview]
Message-ID: <1363198676-30417-2-git-send-email-sboyd@codeaurora.org> (raw)
In-Reply-To: <1363198676-30417-1-git-send-email-sboyd@codeaurora.org>
From: Mark Rutland <mark.rutland@arm.com>
Several architectures have a dummy timer driver tightly coupled with
their broadcast code to support machines without cpu-local timers (or
where there is a lack of driver support).
Since 12ad100046: "clockevents: Add generic timer broadcast function"
it's been possible to write broadcast-capable timer drivers decoupled
from the broadcast mechanism. We can use this functionality to implement
a generic dummy timer driver that can be shared by all architectures
with generic tick broadcast (ARCH_HAS_TICK_BROADCAST).
This patch implements a generic dummy timer using this facility.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
[sboyd: Make percpu data static and use __this_cpu_ptr()]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
drivers/clocksource/Makefile | 1 +
drivers/clocksource/dummy_timer.c | 67 +++++++++++++++++++++++++++++++++++++++
2 files changed, 68 insertions(+)
create mode 100644 drivers/clocksource/dummy_timer.c
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 4d8283a..655d718 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -22,3 +22,4 @@ obj-$(CONFIG_VT8500_TIMER) += vt8500_timer.o
obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o
obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o
+obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST) += dummy_timer.o
diff --git a/drivers/clocksource/dummy_timer.c b/drivers/clocksource/dummy_timer.c
new file mode 100644
index 0000000..7e1ce45
--- /dev/null
+++ b/drivers/clocksource/dummy_timer.c
@@ -0,0 +1,67 @@
+/*
+ * linux/drivers/clocksource/dummy_timer.c
+ *
+ * Copyright (C) 2013 ARM Ltd.
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/clockchips.h>
+#include <linux/cpu.h>
+#include <linux/init.h>
+#include <linux/percpu.h>
+
+static DEFINE_PER_CPU(struct clock_event_device, dummy_timer_evt);
+
+static void dummy_timer_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ /*
+ * Core clockevents code will call this when exchanging timer devices.
+ * We don't need to do anything here.
+ */
+}
+
+static void __cpuinit dummy_timer_setup(void)
+{
+ int cpu = smp_processor_id();
+ struct clock_event_device *evt = __this_cpu_ptr(&dummy_timer_evt);
+
+ evt->name = "dummy_timer";
+ evt->features = CLOCK_EVT_FEAT_PERIODIC |
+ CLOCK_EVT_FEAT_ONESHOT |
+ CLOCK_EVT_FEAT_DUMMY;
+ evt->rating = 100;
+ evt->set_mode = dummy_timer_set_mode;
+ evt->cpumask = cpumask_of(cpu);
+
+ clockevents_register_device(evt);
+}
+
+static int __cpuinit dummy_timer_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ if ((action & ~CPU_TASKS_FROZEN) == CPU_STARTING)
+ dummy_timer_setup();
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block dummy_timer_cpu_nb __cpuinitdata = {
+ .notifier_call = dummy_timer_cpu_notify,
+};
+
+static int __init dummy_timer_register(void)
+{
+ int err = register_cpu_notifier(&dummy_timer_cpu_nb);
+ if (err)
+ return err;
+
+ /* We won't get a call on the boot CPU, so register immediately */
+ dummy_timer_setup();
+
+ return 0;
+}
+device_initcall(dummy_timer_register);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation
next prev parent reply other threads:[~2013-03-13 18:17 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-13 18:17 [PATCHv3 00/10] Remove ARM local timer API Stephen Boyd
2013-03-13 18:17 ` Stephen Boyd [this message]
2013-03-21 18:09 ` [PATCHv3 01/10] clocksource: add generic dummy timer driver Mark Rutland
2013-03-21 18:13 ` Stephen Boyd
2013-03-22 18:03 ` Mark Rutland
2013-03-25 16:49 ` Stephen Boyd
2013-03-25 18:00 ` Mark Rutland
2013-03-25 20:47 ` Thomas Gleixner
2013-03-26 15:26 ` Mark Rutland
2013-03-26 2:14 ` Stephen Boyd
2013-03-26 11:28 ` Mark Rutland
2013-04-05 1:46 ` Stephen Boyd
2013-03-13 18:17 ` [PATCHv3 02/10] ARM: smp: Remove duplicate dummy timer implementation Stephen Boyd
2013-03-13 18:17 ` [PATCHv3 03/10] ARM: smp_twd: Divorce smp_twd from local timer API Stephen Boyd
2013-03-28 15:22 ` Mark Rutland
2013-03-28 20:09 ` Stephen Boyd
2013-04-02 8:41 ` Mark Rutland
2013-03-13 18:17 ` [PATCHv3 04/10] ARM: OMAP2+: Divorce " Stephen Boyd
2013-03-13 18:17 ` [PATCHv3 05/10] ARM: EXYNOS4: Divorce mct " Stephen Boyd
2013-03-13 18:17 ` [PATCHv3 06/10] ARM: PRIMA2: Divorce timer-marco " Stephen Boyd
2013-03-13 18:17 ` [PATCHv3 07/10] ARM: msm: Divorce msm_timer " Stephen Boyd
2013-03-13 18:17 ` [PATCHv3 08/10] clocksource: time-armada-370-xp: Fix sparse warning Stephen Boyd
2013-03-20 17:06 ` Gregory CLEMENT
2013-03-13 18:17 ` [PATCHv3 09/10] clocksource: time-armada-370-xp: Divorce from local timer API Stephen Boyd
2013-03-20 17:09 ` Gregory CLEMENT
2013-03-20 17:20 ` Stephen Boyd
2013-03-20 17:26 ` Gregory CLEMENT
2013-03-20 17:44 ` Gregory CLEMENT
2013-03-20 18:00 ` Stephen Boyd
2013-03-20 17:21 ` Gregory CLEMENT
2013-03-13 18:17 ` [PATCHv3 10/10] ARM: smp: Remove " Stephen Boyd
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1363198676-30417-2-git-send-email-sboyd@codeaurora.org \
--to=sboyd@codeaurora.org \
--cc=john.stultz@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).