On Thursday 29 March 2007 07:08:58 Linus Torvalds wrote:
>
> On Thu, 29 Mar 2007, Maxim wrote:
> >
> > I am sending here a patch that as was discussed here adds hpet to list of system devices
> > and adds suspend/resume hooks this way.
> > I tested it and it works fine.
>
> Ok, it certainly looks better, but it *also* looks like it just assumes
> the HPET is there. Which would work in testing _with_ a HPET, but would
> likely break on hardware without one, no?
>
> Shouldn't there be at least something like a
>
> if (!is_hpet_capable())
> return 0;
>
> at the top of that init routine? I'd also expect that you'd need to check
> that "hpet_virt_address" is valid or something?
>
> (Or, better yet, shouldn't we set "boot_hpet_disable" when we decide not
> to use the HPET, and set hpet_virt_address to NULL?)
This is done here
out_nohpet:
iounmap(hpet_virt_address);
hpet_virt_address = NULL;
>
> Linus
>
Hi,
Of course, I forgot.
I was planning to put sysdev code in hpet_enable()
but it is not possible because this function is called too early.
Thus I put sysdev initialization in separate function but forgot to test for HPET
Thanks a lot.
Best regards
Maxim Levitsky
---
This adds support of suspend/resume on i386 for HPET
Signed-off-by: Maxim Levitsky <maximlevitsky@xxxxxxxxx>
---
arch/i386/kernel/hpet.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 68 insertions(+), 0 deletions(-)
diff --git a/arch/i386/kernel/hpet.c b/arch/i386/kernel/hpet.c
index 0fd9fba..7c67780 100644
--- a/arch/i386/kernel/hpet.c
+++ b/arch/i386/kernel/hpet.c
@@ -3,6 +3,8 @@
#include <linux/errno.h>
#include <linux/hpet.h>
#include <linux/init.h>
+#include <linux/sysdev.h>
+#include <linux/pm.h>
#include <asm/hpet.h>
#include <asm/io.h>
@@ -310,6 +312,7 @@ int __init hpet_enable(void)
out_nohpet:
iounmap(hpet_virt_address);
hpet_virt_address = NULL;
+ boot_hpet_disable = 1;
return 0;
}
@@ -524,3 +527,68 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}
#endif
+
+
+/*
+ * Suspend/resume part
+ */
+
+#ifdef CONFIG_PM
+
+static int hpet_suspend(struct sys_device *sys_device, pm_message_t state)
+{
+ unsigned long cfg = hpet_readl(HPET_CFG);
+
+ cfg &= ~(HPET_CFG_ENABLE|HPET_CFG_LEGACY);
+ hpet_writel(cfg, HPET_CFG);
+
+ return 0;
+}
+
+static int hpet_resume(struct sys_device *sys_device)
+{
+ unsigned int id;
+
+ hpet_start_counter();
+
+ id = hpet_readl(HPET_ID);
+
+ if (id & HPET_ID_LEGSUP)
+ hpet_enable_int();
+
+ return 0;
+}
+
+static struct sysdev_class hpet_class = {
+ set_kset_name("hpet"),
+ .suspend = hpet_suspend,
+ .resume = hpet_resume,
+};
+
+static struct sys_device hpet_device = {
+ .id = 0,
+ .cls = &hpet_class,
+};
+
+
+static __init int hpet_register_sysfs(void)
+{
+ int err;
+
+ if (!is_hpet_capable())
+ return 0;
+
+ err = sysdev_class_register(&hpet_class);
+
+ if (!err) {
+ sysdev_register(&hpet_device);
+ if (err)
+ sysdev_class_unregister(&hpet_class);
+ }
+
+ return err;
+}
+
+device_initcall(hpet_register_sysfs);
+
+#endif
--
1.4.4.2
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