Implement support for fetching nvdimm health information via
H_SCM_HEALTH hcall as documented in Ref[1]. The hcall returns a pair
of 64-bit bitmap, bitwise-and of which is then stored in
'struct papr_scm_priv' and subsequently partially exposed to
user-space via newly introduced dimm specific attribute
'papr/flags'. Since the hcall is costly, the health information is
cached and only re-queried, 60s after the previous successful hcall.
The patch also adds a documentation text describing flags reported by
the the new sysfs attribute 'papr/flags' is also introduced at
Documentation/ABI/testing/sysfs-bus-papr-scm.
[1] commit 58b278f568f0 ("powerpc: Provide initial documentation for
PAPR hcalls")
Cc: "Aneesh Kumar K . V"
Cc: Dan Williams
Cc: Michael Ellerman
Cc: Ira Weiny
Signed-off-by: Vaibhav Jain
---
Changelog:
v7..v8:
* Update type of variable 'rc' in __drc_pmem_query_health() and
drc_pmem_query_health() to long and int respectively. [ Ira ]
* Updated the patch description to s/64 bit Big Endian Number/64-bit
bitmap/ [ Ira, Aneesh ].
Resend:
* None
v6..v7 :
* Used the exported buf_seq_printf() function to generate content for
'papr/flags'
* Moved the PAPR_SCM_DIMM_* bit-flags macro definitions to papr_scm.c
and removed the papr_scm.h file [Mpe]
* Some minor consistency issued in sysfs-bus-papr-scm
documentation. [Mpe]
* s/dimm_mutex/health_mutex/g [Mpe]
* Split drc_pmem_query_health() into two function one of which takes
care of caching and locking. [Mpe]
* Fixed a local copy creation of dimm health information using
READ_ONCE(). [Mpe]
v5..v6 :
* Change the flags sysfs attribute from 'papr_flags' to 'papr/flags'
[Dan Williams]
* Include documentation for 'papr/flags' attr [Dan Williams]
* Change flag 'save_fail' to 'flush_fail' [Dan Williams]
* Caching of health bitmap to reduce expensive hcalls [Dan Williams]
* Removed usage of PPC_BIT from 'papr-scm.h' header [Mpe]
* Replaced two __be64 integers from papr_scm_priv to a single u64
integer [Mpe]
* Updated patch description to reflect the changes made in this
version.
* Removed avoidable usage of 'papr_scm_priv.dimm_mutex' from
flags_show() [Dan Williams]
v4..v5 :
* None
v3..v4 :
* None
v2..v3 :
* Removed PAPR_SCM_DIMM_HEALTH_NON_CRITICAL as a condition for
NVDIMM unarmed [Aneesh]
v1..v2 :
* New patch in the series.
---
Documentation/ABI/testing/sysfs-bus-papr-scm | 27 +++
arch/powerpc/platforms/pseries/papr_scm.c| 169 ++-
2 files changed, 194 insertions(+), 2 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-bus-papr-scm
diff --git a/Documentation/ABI/testing/sysfs-bus-papr-scm
b/Documentation/ABI/testing/sysfs-bus-papr-scm
new file mode 100644
index ..6143d06072f1
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-papr-scm
@@ -0,0 +1,27 @@
+What: /sys/bus/nd/devices/nmemX/papr/flags
+Date: Apr, 2020
+KernelVersion: v5.8
+Contact: linuxppc-dev ,
linux-nvd...@lists.01.org,
+Description:
+ (RO) Report flags indicating various states of a
+ papr-scm NVDIMM device. Each flag maps to a one or
+ more bits set in the dimm-health-bitmap retrieved in
+ response to H_SCM_HEALTH hcall. The details of the bit
+ flags returned in response to this hcall is available
+ at 'Documentation/powerpc/papr_hcalls.rst' . Below are
+ the flags reported in this sysfs file:
+
+ * "not_armed" : Indicates that NVDIMM contents will not
+ survive a power cycle.
+ * "flush_fail" : Indicates that NVDIMM contents
+ couldn't be flushed during last
+ shut-down event.
+ * "restore_fail": Indicates that NVDIMM contents
+ couldn't be restored during NVDIMM
+ initialization.
+ * "encrypted" : NVDIMM contents are encrypted.
+ * "smart_notify": There is health event for the NVDIMM.
+ * "scrubbed": Indicating that contents of the
+ NVDIMM have been scrubbed.
+ * "locked" : Indicating that NVDIMM contents cant
+ be modified until next power cycle.
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c
b/arch/powerpc/platforms/pseries/papr_scm.c
index f35592423380..010cd9aae488 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -12,6 +12,7 @@
#include
#include
#include
+#include
#include
@@ -22,6 +23,44 @@
(1ul << ND_CMD_GET_CONFIG_DATA) | \
(1ul << ND_CMD_SET_CONFIG_DATA))
+/* DIMM health bitmap bitmap indicators */
+/* SCM device is unable to persist memory contents */
+#define PAPR_SCM_DIMM_UNARMED (1ULL << (63 - 0))
+/* SCM device
