[linux-next] [PATCH V2 2/4] ACPI: introduce new mechanism tosave/restore ACPI NVS memory

[Zhang Rui]

According to the ACPI spec, ACPI NVS memory region is required to be
saved/restored by OS during hibernation.

Section 15.3.2 ACPI Spec 3.0b,
"OSPM will call the _PTS control method some time before entering a sleeping state,
to allow the platformâs 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."

Add the mechanism to save/restore ACPI NVS memory during hibernation.

Note: now Linux save ACPI NVS memory in acpi_hibernation_pre_snapshot, and restore it in
	acpi_hibernation_leave. Both of these functions will be invoked only once during
	the hibernate and resume.
Note: in Section 14.3 ACPI spec 3.0b, I only get
	"EfiACPIMemoryNVS: The OS and loader must preserve this memory range in
	the working and ACPI S1âS3 states."
	whether we should save/restore this piece of memory is not cleared.

Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
---
 drivers/acpi/sleep/main.c |  126 +++++++++++++++++++++++++++++++++++++++++++---
 include/linux/acpi.h      |    3 +
 2 files changed, 122 insertions(+), 7 deletions(-)

Index: linux-next/drivers/acpi/sleep/main.c
===================================================================
--- linux-next.orig/drivers/acpi/sleep/main.c	2008-07-11 08:47:33.000000000 +0800
+++ linux-next/drivers/acpi/sleep/main.c	2008-07-11 09:06:12.000000000 +0800
@@ -15,6 +15,7 @@
 #include <linux/dmi.h>
 #include <linux/device.h>
 #include <linux/suspend.h>
+#include <linux/highmem.h>
 
 #include <asm/io.h>
 
@@ -283,10 +284,105 @@
 #endif /* CONFIG_SUSPEND */
 
 #ifdef CONFIG_HIBERNATION
+
+/* ACPI NVS memory need to be saved/stored during hibernation */
+struct nvs_page {
+	unsigned long pfn;
+	void *data;
+	struct list_head node;
+};
+static LIST_HEAD(nvs_pages_list);
+
+int acpi_mark_nvs_region(unsigned long start, unsigned long end)
+{
+	struct nvs_page *pos, *next;
+
+	while (start <= end) {
+		pos = kzalloc(sizeof(struct nvs_page), GFP_KERNEL);
+		if (!pos)
+			goto err;
+		pos->pfn = start;
+		start++;
+		list_add_tail(&pos->node, &nvs_pages_list);
+	}
+	return 0;
+
+err:
+	list_for_each_entry_safe(pos, next, &nvs_pages_list, node) {
+		list_del(&pos->node);
+		kfree(pos);
+	}
+	return -ENOMEM;
+}
+
+static void acpi_free_nvs_pages(void)
+{
+	struct nvs_page *pos;
+
+	list_for_each_entry(pos, &nvs_pages_list, node) {
+		if (!pos->data)
+			break;
+		free_page((long)pos->data);
+		pos->data = NULL;
+	}
+}
+
+static int acpi_allocate_nvs_pages(void)
+{
+	struct nvs_page *pos;
+
+	list_for_each_entry(pos, &nvs_pages_list, node) {
+		pos->data = (void *)__get_free_page(GFP_KERNEL);
+		if (!pos->data) {
+			acpi_free_nvs_pages();
+			return -ENOMEM;
+		}
+	}
+	return 0;
+}
+
+static void acpi_save_nvs_memory(void)
+{
+	void *kaddr;
+	struct nvs_page *pos;
+
+	pr_debug("ACPI: Saving ACPI NVS memory\n");
+	list_for_each_entry(pos, &nvs_pages_list, node) {
+		/* nvs page might not have a 'struct page' */
+		kaddr = kmap_atomic_pfn(pos->pfn, KM_USER0);
+		copy_page(pos->data, kaddr);
+		kunmap_atomic(kaddr, KM_USER0);
+	}
+	return;
+}
+
+static void acpi_restore_nvs_memory(void)
+{
+	void *kaddr;
+	struct nvs_page *pos;
+
+	pr_debug("ACPI: Restoring ACPI NVS memory\n");
+	list_for_each_entry(pos, &nvs_pages_list, node) {
+		kaddr = kmap_atomic_pfn(pos->pfn, KM_USER0);
+		copy_page(kaddr, pos->data);
+		kunmap_atomic(kaddr, KM_USER0);
+	}
+}
+
 static int acpi_hibernation_begin(void)
 {
 	acpi_target_sleep_state = ACPI_STATE_S4;
-	return 0;
+
+	/* allocate pages for ACPI NVS memory before swsusp_shrink_memory */
+	return acpi_allocate_nvs_pages();
+}
+
+static int acpi_hibernation_pre_snapshot(void)
+{
+	int result = acpi_pm_prepare();
+
+	acpi_save_nvs_memory();
+	return result;
 }
 
 static int acpi_hibernation_enter(void)
@@ -307,6 +403,12 @@
 	return ACPI_SUCCESS(status) ? 0 : -EFAULT;
 }
 
+static void acpi_hibernation_end(void)
+{
+	acpi_free_nvs_pages();
+	acpi_pm_end();
+}
+
 static void acpi_hibernation_leave(void)
 {
 	/*
@@ -316,6 +418,7 @@
 	acpi_enable();
 	/* Reprogram control registers and execute _BFS */
 	acpi_leave_sleep_state_prep(ACPI_STATE_S4);
+	acpi_restore_nvs_memory();
 }
 
 static void acpi_pm_enable_gpes(void)
@@ -325,8 +428,8 @@
 
 static struct platform_hibernation_ops acpi_hibernation_ops = {
 	.begin = acpi_hibernation_begin,
-	.end = acpi_pm_end,
-	.pre_snapshot = acpi_pm_prepare,
+	.end = acpi_hibernation_end,
+	.pre_snapshot = acpi_hibernation_pre_snapshot,
 	.finish = acpi_pm_finish,
 	.prepare = acpi_pm_prepare,
 	.enter = acpi_hibernation_enter,
@@ -345,19 +448,28 @@
 {
 	int error = acpi_sleep_prepare(ACPI_STATE_S4);
 
-	if (!error)
-		acpi_target_sleep_state = ACPI_STATE_S4;
+	if (!error) {
+		error = acpi_allocate_nvs_pages();
+		if (!error)
+			acpi_target_sleep_state = ACPI_STATE_S4;
+	}
 	return error;
 }
 
+static int acpi_hibernation_pre_snapshot_old(void)
+{
+	acpi_save_nvs_memory();
+	return acpi_pm_disable_gpes();
+}
+
 /*
  * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
  * been requested.
  */
 static struct platform_hibernation_ops acpi_hibernation_ops_old = {
 	.begin = acpi_hibernation_begin_old,
-	.end = acpi_pm_end,
-	.pre_snapshot = acpi_pm_disable_gpes,
+	.end = acpi_hibernation_end,
+	.pre_snapshot = acpi_hibernation_pre_snapshot_old,
 	.finish = acpi_pm_finish,
 	.prepare = acpi_pm_disable_gpes,
 	.enter = acpi_hibernation_enter,
Index: linux-next/include/linux/acpi.h
===================================================================
--- linux-next.orig/include/linux/acpi.h	2008-07-11 08:47:33.000000000 +0800
+++ linux-next/include/linux/acpi.h	2008-07-11 08:47:45.000000000 +0800
@@ -107,6 +107,9 @@
 void acpi_numa_arch_fixup(void);
 #endif
 
+#ifdef CONFIG_HIBERNATION
+int acpi_mark_nvs_region(unsigned long, unsigned long);
+#endif
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
 /* Arch dependent functions for cpu hotplug support */
 int acpi_map_lsapic(acpi_handle handle, int *pcpu);


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