From: Magnus Damm <magnus.damm@gmail.com>
To: linux-sh@vger.kernel.org
Subject: [PATCH] clocksource: sh_cmt clocksource support
Date: Fri, 17 Apr 2009 05:26:31 +0000 [thread overview]
Message-ID: <20090417052631.8114.81559.sendpatchset@rx1.opensource.se> (raw)
From: Magnus Damm <damm@igel.co.jp>
Add clocksource support to the sh_cmt driver. With this in
place we can do tickless with a single CMT channel.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
---
This patch depends on the following -mm patches:
clocksource-add-enable-and-disable-callbacks.patch
clocksource-pass-clocksource-to-read-callback.patch
drivers/clocksource/sh_cmt.c | 66 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+)
--- 0006/drivers/clocksource/sh_cmt.c
+++ work/drivers/clocksource/sh_cmt.c 2009-02-04 19:48:04.000000000 +0900
@@ -47,6 +47,7 @@ struct sh_cmt_priv {
unsigned long rate;
spinlock_t lock;
struct clock_event_device ced;
+ struct clocksource cs;
unsigned long total_cycles;
};
@@ -376,6 +377,68 @@ static void sh_cmt_stop(struct sh_cmt_pr
spin_unlock_irqrestore(&p->lock, flags);
}
+static struct sh_cmt_priv *cs_to_sh_cmt(struct clocksource *cs)
+{
+ return container_of(cs, struct sh_cmt_priv, cs);
+}
+
+static cycle_t sh_cmt_clocksource_read(struct clocksource *cs)
+{
+ struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
+ unsigned long flags, raw;
+ unsigned long value;
+ int has_wrapped;
+
+ spin_lock_irqsave(&p->lock, flags);
+ value = p->total_cycles;
+ raw = sh_cmt_get_counter(p, &has_wrapped);
+
+ if (unlikely(has_wrapped))
+ raw = p->match_value;
+ spin_unlock_irqrestore(&p->lock, flags);
+
+ return value + raw;
+}
+
+static int sh_cmt_clocksource_enable(struct clocksource *cs)
+{
+ struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
+ int ret;
+
+ p->total_cycles = 0;
+
+ ret = sh_cmt_start(p, FLAG_CLOCKSOURCE);
+ if (ret)
+ return ret;
+
+ /* TODO: calculate good shift from rate and counter bit width */
+ cs->shift = 0;
+ cs->mult = clocksource_hz2mult(p->rate, cs->shift);
+ return 0;
+}
+
+static void sh_cmt_clocksource_disable(struct clocksource *cs)
+{
+ sh_cmt_stop(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
+}
+
+static int sh_cmt_register_clocksource(struct sh_cmt_priv *p,
+ char *name, unsigned long rating)
+{
+ struct clocksource *cs = &p->cs;
+
+ cs->name = name;
+ cs->rating = rating;
+ cs->read = sh_cmt_clocksource_read;
+ cs->enable = sh_cmt_clocksource_enable;
+ cs->disable = sh_cmt_clocksource_disable;
+ cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
+ cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
+ pr_info("sh_cmt: %s used as clock source\n", cs->name);
+ clocksource_register(cs);
+ return 0;
+}
+
static struct sh_cmt_priv *ced_to_sh_cmt(struct clock_event_device *ced)
{
return container_of(ced, struct sh_cmt_priv, ced);
@@ -484,6 +547,9 @@ int sh_cmt_register(struct sh_cmt_priv *
if (clockevent_rating)
sh_cmt_register_clockevent(p, name, clockevent_rating);
+ if (clocksource_rating)
+ sh_cmt_register_clocksource(p, name, clocksource_rating);
+
return 0;
}
next reply other threads:[~2009-04-17 5:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-17 5:26 Magnus Damm [this message]
2009-04-22 0:27 ` [PATCH] clocksource: sh_cmt clocksource support Paul Mundt
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=20090417052631.8114.81559.sendpatchset@rx1.opensource.se \
--to=magnus.damm@gmail.com \
--cc=linux-sh@vger.kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.