suspend: Move NVS save/restore code to generic suspend functionality

Saving platform non-volatile state may be required for suspend to RAM as
well as hibernation. Move it to more generic code.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 136 insertions, 0 deletions

diff --git a/kernel/power/nvs.c b/kernel/power/nvs.c
new file mode 100644
index 000000000000..1836db60bbb6
--- /dev/null
+++ b/kernel/power/nvs.c
@@ -0,0 +1,136 @@
+/*
+ * linux/kernel/power/hibernate_nvs.c - Routines for handling NVS memory
+ *
+ * Copyright (C) 2008,2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+
+/*
+ * Platforms, like ACPI, may want us to save some memory used by them during
+ * suspend 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);
+
+/**
+ *      suspend_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 suspend_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;
+}
+
+/**
+ *      suspend_nvs_free - free data pages allocated for saving NVS regions
+ */
+void suspend_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;
+                        }
+                }
+}
+
+/**
+ *      suspend_nvs_alloc - allocate memory necessary for saving NVS regions
+ */
+int suspend_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) {
+                        suspend_nvs_free();
+                        return -ENOMEM;
+                }
+        }
+        return 0;
+}
+
+/**
+ *      suspend_nvs_save - save NVS memory regions
+ */
+void suspend_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);
+                }
+}
+
+/**
+ *      suspend_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 suspend_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);
+}