OMAP: PM noop: implement context loss count for non-omap_devices

For devices which have not (yet) been converted to use omap_device,
implement the context loss counter using the "brutal method" as
originally proposed by Paul Walmsley[1].

The dummy context loss counter is incremented every time it is
checked, but only when off-mode is enabled.  When off-mode is
disabled, the dummy counter stops incrementing.

Tested on 36xx/Zoom3 using MMC driver, which is currently the
only in-tree user of this API.

This patch should be reverted after all devices are converted to using
omap_device.

[1] http://marc.info/?l=linux-omap&m=129176260000626&w=2

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
[paul@pwsan.com: fixed compile warning; fixed to compile on OMAP1]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

1 files changed, 45 insertions, 1 deletions

diff --git a/arch/arm/plat-omap/omap-pm-noop.c b/arch/arm/plat-omap/omap-pm-noop.c
index af58daddcf50..b0471bb2d47d 100644
--- a/arch/arm/plat-omap/omap-pm-noop.c
+++ b/arch/arm/plat-omap/omap-pm-noop.c
@@ -26,6 +26,9 @@
 #include <plat/omap-pm.h>
 #include <plat/omap_device.h>
 
+static bool off_mode_enabled;
+static u32 dummy_context_loss_counter;
+
 /*
  * Device-driver-originated constraints (via board-*.c files)
  */
@@ -280,10 +283,34 @@ unsigned long omap_pm_cpu_get_freq(void)
         return 0;
 }
 
+/**
+ * omap_pm_enable_off_mode - notify OMAP PM that off-mode is enabled
+ *
+ * Intended for use only by OMAP PM core code to notify this layer
+ * that off mode has been enabled.
+ */
+void omap_pm_enable_off_mode(void)
+{
+        off_mode_enabled = true;
+}
+
+/**
+ * omap_pm_disable_off_mode - notify OMAP PM that off-mode is disabled
+ *
+ * Intended for use only by OMAP PM core code to notify this layer
+ * that off mode has been disabled.
+ */
+void omap_pm_disable_off_mode(void)
+{
+        off_mode_enabled = false;
+}
+
 /*
  * Device context loss tracking
  */
 
+#ifdef CONFIG_ARCH_OMAP2PLUS
+
 u32 omap_pm_get_dev_context_loss_count(struct device *dev)
 {
         struct platform_device *pdev = to_platform_device(dev);
@@ -292,13 +319,30 @@ u32 omap_pm_get_dev_context_loss_count(struct device *dev)
         if (WARN_ON(!dev))
                 return 0;
 
-        count = omap_device_get_context_loss_count(pdev);
+        if (dev->parent == &omap_device_parent) {
+                count = omap_device_get_context_loss_count(pdev);
+        } else {
+                WARN_ONCE(off_mode_enabled, "omap_pm: using dummy context loss counter; device %s should be converted to omap_device",
+                          dev_name(dev));
+                if (off_mode_enabled)
+                        dummy_context_loss_counter++;
+                count = dummy_context_loss_counter;
+        }
+
         pr_debug("OMAP PM: context loss count for dev %s = %d\n",
                  dev_name(dev), count);
 
         return count;
 }
 
+#else
+
+u32 omap_pm_get_dev_context_loss_count(struct device *dev)
+{
+        return dummy_context_loss_counter;
+}
+
+#endif
 
 /* Should be called before clk framework init */
 int __init omap_pm_if_early_init(void)