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>

1 files changed, 45 insertions, 8 deletions

diff --git a/drivers/acpi/sleep/main.c b/drivers/acpi/sleep/main.c
index 28a691cc625e..45a8015e4217 100644
--- a/drivers/acpi/sleep/main.c
+++ b/drivers/acpi/sleep/main.c
@@ -394,9 +394,25 @@ void __init acpi_no_s4_hw_signature(void)
 
 static int acpi_hibernation_begin(void)
 {
-        acpi_target_sleep_state = ACPI_STATE_S4;
-        acpi_sleep_tts_switch(acpi_target_sleep_state);
-        return 0;
+        int error;
+
+        error = hibernate_nvs_alloc();
+        if (!error) {
+                acpi_target_sleep_state = ACPI_STATE_S4;
+                acpi_sleep_tts_switch(acpi_target_sleep_state);
+        }
+
+        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)
@@ -417,6 +433,12 @@ 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)
 {
         /*
@@ -432,6 +454,8 @@ 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)
@@ -442,8 +466,8 @@ 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,
@@ -469,8 +493,21 @@ static int acpi_hibernation_begin_old(void)
 
         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;
 }
 
@@ -481,8 +518,8 @@ static int acpi_hibernation_begin_old(void)
 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,