ACPI hibernate: Add a mechanism to save/restore ACPI NVS memory

[linux-2.6-omap-h63xx.git] / kernel / power / swsusp.c

diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index 023ff2a31d899159e61ffb72e9e4eeea65d93b25..a92c9145155975b306d52dab08fb095e3af8370e 100644 (file)
--- 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);
+}