[Proposal][PATCH] sh: PMB hibernation support

[Proposal][PATCH] sh: PMB hibernation support

[Francesco VIRLINZI]

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Hi Paul
>
> Feel free to post what you already have, even if it doesn't apply. This
> sort of stuff by nature tends to take several iterations before it's in
> any shape to merge anyways.
>
>   
In attach there is a proposal on how manage the PMB after a resume from 
hibernation.
My assumption in background is that "just because the kernel runs.. the 
"core" PMB (main memory) are already ok"
In our kernel I'm doing something very similar.
I can say: it compiles but I have no way to really test this code as it is.

Regards
 Francesco

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From f7ac0e9ecd48c8987a747968a79a94ac3f424adc Mon Sep 17 00:00:00 2001
From: Francesco Virlinzi <francesco.virlinzi@st.com>
Date: Wed, 11 Mar 2009 11:31:52 +0100
Subject: [PATCH] sh_mmu: Added hibernation support in the PMB


Signed-off-by: Francesco Virlinzi <francesco.virlinzi@st.com>
---
 arch/sh/mm/pmb.c |   38 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 38 insertions(+), 0 deletions(-)

diff --git a/arch/sh/mm/pmb.c b/arch/sh/mm/pmb.c
index 8424167..b1a714a 100644
--- a/arch/sh/mm/pmb.c
+++ b/arch/sh/mm/pmb.c
@@ -15,6 +15,8 @@
  */
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/sysdev.h>
+#include <linux/cpu.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/bitops.h>
@@ -402,3 +404,39 @@ static int __init pmb_debugfs_init(void)
 	return 0;
 }
 postcore_initcall(pmb_debugfs_init);
+
+#ifdef CONFIG_PM
+static int pmb_sysdev_suspend(struct sys_device *dev, pm_message_t state)
+{
+	static pm_message_t prev_state;
+
+	/* Restore the PMB after a resume from hibernation */
+	if (state.event == PM_EVENT_ON &&
+	    prev_state.event == PM_EVENT_FREEZE) {
+		struct pmb_entry *pmbe;
+		spin_lock_irq(&pmb_list_lock);
+		for (pmbe = pmb_list; pmbe; pmbe = pmbe->next)
+			set_pmb_entry(pmbe);
+		spin_unlock_irq(&pmb_list_lock);
+	}
+	prev_state = state;
+	return 0;
+}
+
+static int pmb_sysdev_resume(struct sys_device *dev)
+{
+	return pmb_sysdev_suspend(dev, PMSG_ON);
+}
+
+static struct sysdev_driver pmb_sysdev_driver = {
+	.suspend = pmb_sysdev_suspend,
+	.resume = pmb_sysdev_resume,
+};
+
+static int __init pmb_sysdev_init(void)
+{
+	return sysdev_driver_register(&cpu_sysdev_class, &pmb_sysdev_driver);
+}
+
+subsys_initcall(pmb_sysdev_init);
+#endif
-- 
1.5.6.6

Re: [Proposal][PATCH] sh: PMB hibernation support

[Paul Mundt]

On Wed, Mar 11, 2009 at 11:39:02AM +0100, Francesco VIRLINZI wrote:
> In attach there is a proposal on how manage the PMB after a resume from 
> hibernation.
> My assumption in background is that "just because the kernel runs.. the 
> "core" PMB (main memory) are already ok"
> In our kernel I'm doing something very similar.
> I can say: it compiles but I have no way to really test this code as it is.
> 
This looks like as good a place as any to start, so I'll merge this for
now, and we can build on top of this incrementally as other cases pop up.