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authorRafael J. Wysocki <rjw@sisk.pl>2008-10-26 20:52:15 +0100
committerLen Brown <len.brown@intel.com>2008-12-19 04:40:34 -0500
commit3f4b0ef7f2899c91b1d6958779f084b44dd59d32 (patch)
treec026201981ecac9c575653c9a46e4c1dea1245a2 /kernel/power
parent3fe0313e6ec572e6bb3f9d247316a834336db4be (diff)
downloadlinux-3f4b0ef7f2899c91b1d6958779f084b44dd59d32.tar.bz2
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@sisk.pl> Acked-by: Nigel Cunningham <nigel@tuxonice.net> Cc: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'kernel/power')
-rw-r--r--kernel/power/swsusp.c122
1 files changed, 122 insertions, 0 deletions
diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index 023ff2a31d89..a92c91451559 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -262,3 +262,125 @@ 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
+ */
+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);
+}