From: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
To: benh@kernel.crashing.org
Cc: nfont@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org,
Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Subject: [PATCH v3 3/3] powerpc/pseries: Report in kernel device tree update to drmgr
Date: Wed, 19 Feb 2014 12:56:55 -0800 [thread overview]
Message-ID: <1392843415-17153-5-git-send-email-tyreld@linux.vnet.ibm.com> (raw)
In-Reply-To: <1392843415-17153-1-git-send-email-tyreld@linux.vnet.ibm.com>
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 <tyreld@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 1d9c580..b87b978 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -192,7 +192,30 @@ 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",
--
1.7.12.2
next prev parent reply other threads:[~2014-02-19 20:59 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-19 20:56 [PATCH v4 0/3] powerpc/pseries: fix issues in suspend/resume code Tyrel Datwyler
2014-02-19 20:56 ` [PATCH v4 1/3] powerpc/pseries: Device tree should only be updated once after suspend/migrate Tyrel Datwyler
2014-02-19 20:56 ` [PATCH v4 2/3] powerpc/pseries: Update dynamic cache nodes for suspend/resume operation Tyrel Datwyler
2014-02-26 4:02 ` [prefix=PATCH v5 " Tyrel Datwyler
2014-02-19 20:56 ` [PATCH v4 3/3] powerpc/pseries: Expose in kernel device tree update to drmgr Tyrel Datwyler
2014-02-19 20:56 ` Tyrel Datwyler [this message]
2014-02-19 22:07 ` [PATCH v3 3/3] powerpc/pseries: Report " Tyrel Datwyler
2014-02-24 1:53 ` [PATCH v4 0/3] powerpc/pseries: fix issues in suspend/resume code Benjamin Herrenschmidt
2014-02-26 4:06 ` Tyrel Datwyler
-- strict thread matches above, loose matches on Subject: below --
2014-01-31 23:58 [PATCH v3 " Tyrel Datwyler
2014-01-31 23:58 ` [PATCH v3 3/3] powerpc/pseries: Report in kernel device tree update to drmgr Tyrel Datwyler
2014-02-17 0:22 ` Benjamin Herrenschmidt
2014-02-18 23:28 ` Tyrel Datwyler
2014-02-18 23:47 ` Benjamin Herrenschmidt
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