sh: hibernation support

Commit Message

Francesco VIRLINZI March 10, 2009, 1:19 p.m. UTC

Hi Magnus
In the clock framework I would propose the attached solution
Regards
 Francesco
Magnus Damm ha scritto:
> On Mon, Mar 9, 2009 at 7:03 PM, Francesco VIRLINZI
> <[e-mail]> wrote:
>   
>> I'm sorry if I'm stressing you but you will have similar problem also with
>> the clock framework.
>> A simple
>> -  clk_get_rate(...)
>> could return a wrong value if in the previous session someone changed the
>> clock rate (from init value) and
>> you don't force again in the hw the resumed "clk->rate".
>>     
>
> Yeah, the clock framework needs more work. =)
>
> / magnus
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Patch

From 7d2249e98d304181b3deaa806ee475873e822328 Mon Sep 17 00:00:00 2001
From: Francesco Virlinzi <[e-mail]>
Date: Tue, 10 Mar 2009 10:23:23 +0100
Subject: [PATCH] sh_clk: Added clks sysdevice to support hibernation

This patch adds the clk_sysdev device to restore the right clocks
 setting after a resume from hibernation.

Signed-off-by: Francesco Virlinzi <[e-mail]>
---
 arch/sh/kernel/cpu/clock.c |   62 ++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 62 insertions(+), 0 deletions(-)

diff --git a/arch/sh/kernel/cpu/clock.c b/arch/sh/kernel/cpu/clock.c
index dc53def..06fcbf0 100644
--- a/arch/sh/kernel/cpu/clock.c
+++ b/arch/sh/kernel/cpu/clock.c
@@ -20,6 +20,8 @@ 
 #include <linux/mutex.h>
 #include <linux/list.h>
 #include <linux/kref.h>
+#include <linux/kobject.h>
+#include <linux/sysdev.h>
 #include <linux/seq_file.h>
 #include <linux/err.h>
 #include <linux/platform_device.h>
@@ -382,6 +384,56 @@  static int show_clocks(char *buf, char **start, off_t off,
 	return p - buf;
 }
 
+static int clks_suspend(struct sys_device *dev, pm_message_t state)
+{
+	static pm_message_t prev_state;
+	struct clk *clkp;
+
+	switch (state.event) {
+	case PM_EVENT_ON:
+		/* Resumeing from hibernation */
+		if (prev_state.event == PM_EVENT_FREEZE) {
+			list_for_each_entry(clkp, &clock_list, node)
+				if (likely(clkp->ops)) {
+					if (likely(clkp->ops->set_parent))
+						clkp->ops->set_parent(clkp,
+							clkp->parent);
+					if (likely(clkp->ops->set_rate))
+						clkp->ops->set_rate(clkp,
+							clkp->rate, NO_CHANGE);
+					if (likely(clkp->ops->recalc))
+						clkp->ops->recalc(clkp);
+					}
+		}
+		break;
+	case PM_EVENT_FREEZE:
+		break;
+	case PM_EVENT_SUSPEND:
+		break;
+	}
+
+	prev_state = state;
+	return 0;
+}
+
+static int clks_resume(struct sys_device *dev)
+{
+	return clks_suspend(dev, PMSG_ON);
+}
+
+static struct sysdev_class clks_class = {
+	.kset.kobj.name = "clks",
+};
+
+static struct sysdev_driver clks_driver = {
+	.suspend = clks_suspend,
+	.resume = clks_resume,
+};
+
+static struct sys_device clks_dev = {
+	.cls = &clks_class,
+};
+
 int __init clk_init(void)
 {
 	int i, ret = 0;
@@ -404,6 +456,16 @@  int __init clk_init(void)
 	return ret;
 }
 
+static int __init clk_sysdev_init(void)
+{
+
+	sysdev_class_register(&clks_class);
+	sysdev_driver_register(&clks_class, &clks_driver);
+	sysdev_register(&clks_dev);
+	return 0;
+}
+subsys_initcall(clk_sysdev_init);
+
 static int __init clk_proc_init(void)
 {
 	struct proc_dir_entry *p;
-- 
1.5.6.6