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author | Tyrel Datwyler <tyreld@linux.vnet.ibm.com> | 2014-02-19 12:56:54 -0800 |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-03-07 15:54:50 +1100 |
commit | 9da3489210fe1870491b0cc49c0304994baa7e96 (patch) | |
tree | ee2ae2d35f9ddc92ae3a025637827b4ac242f7d9 /arch/powerpc/platforms/pseries/suspend.c | |
parent | 6b36ba8492abd1c819e949e085cc547b062d8593 (diff) | |
download | linux-9da3489210fe1870491b0cc49c0304994baa7e96.tar.bz2 |
powerpc/pseries: Expose in kernel device tree update to drmgr
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 an update
entirely in the kernel during the resume. Therefore, a mechanism is required
to expose that information to drmgr.
This patch adds a show function to the "hibernate" attribute that returns 1
if the kernel performs a device tree update after the resume and 0 otherwise.
This allows newer versions of drmgr to avoid doing a second unnecessary
device tree update.
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/platforms/pseries/suspend.c')
-rw-r--r-- | arch/powerpc/platforms/pseries/suspend.c | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c index 1d9c580ab772..b87b97849d4c 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", |