Re: [PATCH 2/4] ACPI hibernate: Add a mechanism to save/restore ACPI NVS memory (rev. 2)

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Hi.
On Thu, 2008-10-23 at 07:47 +0200, Rafael J. Wysocki wrote:> On Thursday, 23 of October 2008, Nigel Cunningham wrote:> > On Thu, 2008-10-23 at 01:08 +0200, Rafael J. Wysocki wrote:> > > On Thursday, 23 of October 2008, Nigel Cunningham wrote:> > > > On Wed, 2008-10-22 at 22:52 +0200, Rafael J. Wysocki wrote:> > > > > From: Rafael J. Wysocki <rjw@xxxxxxx>> [--snip--]> > > > > +/**> > > > > + *	hibernate_nvs_save - save NVS memory regions> > > > > + */> > > > > +void hibernate_nvs_save(void)> > > > > +{> > > > > +	struct nvs_page *entry;> > > > > +> > > > > +	printk(KERN_INFO "PM: Saving platform NVS memory\n");> > > > > +> > > > > +	list_for_each_entry(entry, &nvs_list, node)> > > > > +		if (entry->data) {> > > > > +			entry->kaddr = ioremap(entry->phys_start, entry->size);> > > > > +			memcpy(entry->data, entry->kaddr, entry->size);> > > > > > > > Why not unmap here? (I know you're delaying the unmap until the free,> > > > but it's probably clearer to map and unmap each time the memory is> > > > accessed (ie in restore too).> > > > > > Ah, this one is tricky.  We cannot unmap from atomic context. :-)> > > > Maybe a comment then, lest someone get the same idea in future and be as> > ignorant as me? :)> > Well, I was considering to add one, now changed the kerneldoc comment to> mention that.
Terrific. Thanks.
> Please find updated patch below.> > ---> From: Rafael J. Wysocki <rjw@xxxxxxx>> > ACPI hibernate: Add a mechanism to save/restore ACPI NVS memory (rev. 2)> > According to the ACPI Specification 3.0b, Section 15.3.2,> "OSPM will call the _PTS control method some time before entering a> sleeping state, to allow the platform’s AML code to update this> memory image before entering the sleeping state. After the system> awakes from an S4 state, OSPM will restore this memory area and call> the _WAK control method to enable the BIOS to reclaim its memory> image."  For this reason, implement a mechanism allowing us to save> the NVS memory during hibernation and to restore it during the> subsequent resume.> > Based on a patch by Zhang Rui.> > Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>> Acked-by: Nigel Cunningham <nigel@xxxxxxxxxxxx>> Cc: Zhang Rui <rui.zhang@xxxxxxxxx>> --->  drivers/acpi/sleep/main.c |   50 +++++++++++++++--->  include/linux/suspend.h   |   13 ++++>  kernel/power/swsusp.c     |  124 ++++++++++++++++++++++++++++++++++++++++++++++>  3 files changed, 180 insertions(+), 7 deletions(-)> > Index: linux-2.6/drivers/acpi/sleep/main.c> ===================================================================> --- linux-2.6.orig/drivers/acpi/sleep/main.c> +++ linux-2.6/drivers/acpi/sleep/main.c> @@ -321,8 +321,23 @@ void __init acpi_no_s4_hw_signature(void>  >  static int acpi_hibernation_begin(void)>  {> -	acpi_target_sleep_state = ACPI_STATE_S4;> -	return 0;> +	int error;> +> +	error = hibernate_nvs_alloc();> +	if (!error)> +		acpi_target_sleep_state = ACPI_STATE_S4;> +> +	return error;> +}> +> +static int acpi_hibernation_pre_snapshot(void)> +{> +	int error = acpi_pm_prepare();> +> +	if (!error)> +		hibernate_nvs_save();> +> +	return error;>  }>  >  static int acpi_hibernation_enter(void)> @@ -343,6 +358,12 @@ static int acpi_hibernation_enter(void)>  	return ACPI_SUCCESS(status) ? 0 : -EFAULT;>  }>  > +static void acpi_hibernation_finish(void)> +{> +	hibernate_nvs_free();> +	acpi_pm_finish();> +}> +>  static void acpi_hibernation_leave(void)>  {>  	/*> @@ -358,6 +379,8 @@ static void acpi_hibernation_leave(void)>  			"cannot resume!\n");>  		panic("ACPI S4 hardware signature mismatch");>  	}> +	/* Restore the NVS memory area */> +	hibernate_nvs_restore();>  }>  >  static void acpi_pm_enable_gpes(void)> @@ -368,8 +391,8 @@ static void acpi_pm_enable_gpes(void)>  static struct platform_hibernation_ops acpi_hibernation_ops = {>  	.begin = acpi_hibernation_begin,>  	.end = acpi_pm_end,> -	.pre_snapshot = acpi_pm_prepare,> -	.finish = acpi_pm_finish,> +	.pre_snapshot = acpi_hibernation_pre_snapshot,> +	.finish = acpi_hibernation_finish,>  	.prepare = acpi_pm_prepare,>  	.enter = acpi_hibernation_enter,>  	.leave = acpi_hibernation_leave,> @@ -387,8 +410,21 @@ static int acpi_hibernation_begin_old(vo>  {>  	int error = acpi_sleep_prepare(ACPI_STATE_S4);>  > +	if (!error) {> +		error = hibernate_nvs_alloc();> +		if (!error)> +			acpi_target_sleep_state = ACPI_STATE_S4;> +	}> +	return error;> +}> +> +static int acpi_hibernation_pre_snapshot_old(void)> +{> +	int error = acpi_pm_disable_gpes();> +>  	if (!error)> -		acpi_target_sleep_state = ACPI_STATE_S4;> +		hibernate_nvs_save();> +>  	return error;>  }>  > @@ -399,8 +435,8 @@ static int acpi_hibernation_begin_old(vo>  static struct platform_hibernation_ops acpi_hibernation_ops_old = {>  	.begin = acpi_hibernation_begin_old,>  	.end = acpi_pm_end,> -	.pre_snapshot = acpi_pm_disable_gpes,> -	.finish = acpi_pm_finish,> +	.pre_snapshot = acpi_hibernation_pre_snapshot_old,> +	.finish = acpi_hibernation_finish,>  	.prepare = acpi_pm_disable_gpes,>  	.enter = acpi_hibernation_enter,>  	.leave = acpi_hibernation_leave,> Index: linux-2.6/include/linux/suspend.h> ===================================================================> --- linux-2.6.orig/include/linux/suspend.h> +++ linux-2.6/include/linux/suspend.h> @@ -233,6 +233,11 @@ extern unsigned long get_safe_page(gfp_t>  extern void hibernation_set_ops(struct platform_hibernation_ops *ops);>  extern int hibernate(void);>  extern bool system_entering_hibernation(void);> +extern int hibernate_nvs_register(unsigned long start, unsigned long size);> +extern int hibernate_nvs_alloc(void);> +extern void hibernate_nvs_free(void);> +extern void hibernate_nvs_save(void);> +extern void hibernate_nvs_restore(void);>  #else /* CONFIG_HIBERNATION */>  static inline int swsusp_page_is_forbidden(struct page *p) { return 0; }>  static inline void swsusp_set_page_free(struct page *p) {}> @@ -241,6 +246,14 @@ static inline void swsusp_unset_page_fre>  static inline void hibernation_set_ops(struct platform_hibernation_ops *ops) {}>  static inline int hibernate(void) { return -ENOSYS; }>  static inline bool system_entering_hibernation(void) { return false; }> +static inline int hibernate_nvs_register(unsigned long a, unsigned long b)> +{> +	return 0;> +}> +static inline int hibernate_nvs_alloc(void) { return 0; }> +static inline void hibernate_nvs_free(void) {}> +static inline void hibernate_nvs_save(void) {}> +static inline void hibernate_nvs_restore(void) {}>  #endif /* CONFIG_HIBERNATION */>  >  #ifdef CONFIG_PM_SLEEP> Index: linux-2.6/kernel/power/swsusp.c> ===================================================================> --- linux-2.6.orig/kernel/power/swsusp.c> +++ linux-2.6/kernel/power/swsusp.c> @@ -262,3 +262,127 @@ int swsusp_shrink_memory(void)>  >  	return 0;>  }> +> +/*> + * Platforms, like ACPI, may want us to save some memory used by them during
Both commas should be removed from the line above.
> + * hibernation and to restore the contents of this memory during the subsequent> + * resume.  The code below implements a mechanism allowing us to do that.> + */> +> +struct nvs_page {> +	unsigned long phys_start;> +	unsigned int size;> +	void *kaddr;> +	void *data;> +	struct list_head node;> +};> +> +static LIST_HEAD(nvs_list);> +> +/**> + *	hibernate_nvs_register - register platform NVS memory region to save> + *	@start - physical address of the region> + *	@size - size of the region> + *> + *	The NVS region need not be page-aligned (both ends) and we arrange> + *	things so that the data from page-aligned addresses in this region will> + *	be copied into separate RAM pages.> + */> +int hibernate_nvs_register(unsigned long start, unsigned long size)> +{> +	struct nvs_page *entry, *next;> +> +	while (size > 0) {> +		unsigned int nr_bytes;> +> +		entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL);> +		if (!entry)> +			goto Error;> +> +		list_add_tail(&entry->node, &nvs_list);> +		entry->phys_start = start;> +		nr_bytes = PAGE_SIZE - (start & ~PAGE_MASK);> +		entry->size = (size < nr_bytes) ? size : nr_bytes;> +> +		start += entry->size;> +		size -= entry->size;> +	}> +	return 0;> +> + Error:> +	list_for_each_entry_safe(entry, next, &nvs_list, node) {> +		list_del(&entry->node);> +		kfree(entry);> +	}> +	return -ENOMEM;> +}> +> +/**> + *	hibernate_nvs_free - free data pages allocated for saving NVS regions> + *> + *	It is allowed to call this function many times in a row.
"This function may safely be called multiple times." .... maybe just dowithout the comment?
> + */> +void hibernate_nvs_free(void)> +{> +	struct nvs_page *entry;> +> +	list_for_each_entry(entry, &nvs_list, node)> +		if (entry->data) {> +			free_page((unsigned long)entry->data);> +			entry->data = NULL;> +			if (entry->kaddr) {> +				iounmap(entry->kaddr);> +				entry->kaddr = NULL;> +			}> +		}> +}> +> +/**> + *	hibernate_nvs_alloc - allocate memory necessary for saving NVS regions> + */> +int hibernate_nvs_alloc(void)> +{> +	struct nvs_page *entry;> +> +	list_for_each_entry(entry, &nvs_list, node) {> +		entry->data = (void *)__get_free_page(GFP_KERNEL);> +		if (!entry->data) {> +			hibernate_nvs_free();> +			return -ENOMEM;> +		}> +	}> +	return 0;> +}> +> +/**> + *	hibernate_nvs_save - save NVS memory regions> + */> +void hibernate_nvs_save(void)> +{> +	struct nvs_page *entry;> +> +	printk(KERN_INFO "PM: Saving platform NVS memory\n");> +> +	list_for_each_entry(entry, &nvs_list, node)> +		if (entry->data) {> +			entry->kaddr = ioremap(entry->phys_start, entry->size);> +			memcpy(entry->data, entry->kaddr, entry->size);> +		}> +}> +> +/**> + *	hibernate_nvs_restore - restore NVS memory regions> + *> + *	This function is going to be called with interrupts disabled, so it> + *	cannot iounmap the virtual addresses used to access the NVS region.> + */> +void hibernate_nvs_restore(void)> +{> +	struct nvs_page *entry;> +> +	printk(KERN_INFO "PM: Restoring platform NVS memory\n");> +> +	list_for_each_entry(entry, &nvs_list, node)> +		if (entry->data)> +			memcpy(entry->kaddr, entry->data, entry->size);> +}
Regards,
Nigel
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