Traditionally it has been drmgr's responsibilty to update the device tree
through the /proc/ppc64/ofdt interface after a suspend/resume operation.
This patchset however has modified suspend/resume ops to preform that update
entirely in the kernel during the resume. Therefore, a mechanism is required
for drmgr to determine who is responsible for the update. This patch adds a
show function to the "hibernate" attribute that returns 1 if the kernel
updates the device tree after the resume and 0 if drmgr is responsible.
Signed-off-by: Tyrel Datwyler <tyr...@linux.vnet.ibm.com>
---
arch/powerpc/platforms/pseries/suspend.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/pseries/suspend.c
b/arch/powerpc/platforms/pseries/suspend.c
index 16a2552..723115d 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -174,7 +174,30 @@ out:
return rc;
}
-static DEVICE_ATTR(hibernate, S_IWUSR, NULL, store_hibernate);
+#define USER_DT_UPDATE 0
+#define KERN_DT_UPDATE 1
+
+/**
+ * show_hibernate - Report device tree update responsibilty
+ * @dev: subsys root device
+ * @attr: device attribute struct
+ * @buf: buffer
+ *
+ * Report whether a device tree update is performed by the kernel after a
+ * resume, or if drmgr must coordinate the update from user space.
+ *
+ * Return value:
+ * 0 if drmgr is to initiate update, and 1 otherwise
+ **/
+static ssize_t show_hibernate(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%d\n", KERN_DT_UPDATE);
+}
+
+static DEVICE_ATTR(hibernate, S_IWUSR | S_IRUGO,
+ show_hibernate, store_hibernate);
static struct bus_type suspend_subsys = {
.name = "power",
--
1.7.12.4
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
