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
_______________________________________________linux-pm mailing listlinux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx://lists.linux-foundation.org/mailman/listinfo/linux-pm
