Hi.
On Thu, 2008-10-23 at 01:08 +0200, Rafael J. Wysocki wrote:> On Thursday, 23 of October 2008, Nigel Cunningham wrote:> > Hi.> > Hi,> > > On Wed, 2008-10-22 at 22:52 +0200, Rafael J. Wysocki wrote:> > > From: Rafael J. Wysocki <rjw@xxxxxxx>> > > > > > ACPI hibernate: Add a mechanism to save/restore ACPI NVS memory> > > > > > 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>> > > Cc: Zhang Rui <rui.zhang@xxxxxxxxx>> > > ---> > > drivers/acpi/sleep/main.c | 50 ++++++++++++++++---> > > include/linux/suspend.h | 13 ++++> > > kernel/power/swsusp.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++> > > 3 files changed, 177 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 +262,124 @@ int swsusp_shrink_memory(void)> > > > > > return 0;> > > }> > > +> > > +/*> > > + * Platforms, like ACPI, may want us to save some memory used by them during> > > + * 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.> > > + */> > > > If this one is safe for multiple calls, should nvs_alloc be safe for> > multiple calls too? Or, conversely, is something funny going on such> > that hibernate_nvs_free needs to be safe for multiple calls?> > I thought it would be necessary to call that additionally from platform_end()> for the error path in which platform_pre_snapshot() fails, but that doesn't> seem to be the case. It doesn't hurt to keep it in this form, though, IMO.
Okee doke.
> > > +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);> > > > 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 asignorant as me? :)
> > > + }> > > +}> > > +> > > +/**> > > + * hibernate_nvs_restore - restore NVS memory regions> > > + */> > > +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);> > > +}> > Thanks,> Rafael
Acked-by: Nigel Cunningham <nigel@xxxxxxxxxxxx>
Regards,
Nigel
_______________________________________________linux-pm mailing listlinux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx://lists.linux-foundation.org/mailman/listinfo/linux-pm
