From 75b7c05ebf902632f7f540c3eb0a8945c2d74aab Mon Sep 17 00:00:00 2001 From: Shivaprasad G Bhat Date: Mon, 29 Mar 2021 13:36:43 -0400 Subject: powerpc/papr_scm: Implement support for H_SCM_FLUSH hcall Add support for ND_REGION_ASYNC capability if the device tree indicates 'ibm,hcall-flush-required' property in the NVDIMM node. Flush is done by issuing H_SCM_FLUSH hcall to the hypervisor. If the flush request failed, the hypervisor is expected to to reflect the problem in the subsequent nvdimm H_SCM_HEALTH call. This patch prevents mmap of namespaces with MAP_SYNC flag if the nvdimm requires an explicit flush[1]. References: [1] https://github.com/avocado-framework-tests/avocado-misc-tests/blob/master/memory/ndctl.py.data/map_sync.c Signed-off-by: Shivaprasad G Bhat Reviewed-by: Aneesh Kumar K.V [mpe: Use unsigned long / long instead of uint64_t/int64_t] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/161703936121.36.7260632399582101498.stgit@e1fbed493c87 --- Documentation/powerpc/papr_hcalls.rst | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'Documentation/powerpc') diff --git a/Documentation/powerpc/papr_hcalls.rst b/Documentation/powerpc/papr_hcalls.rst index 48fcf1255a33..648f278eea8f 100644 --- a/Documentation/powerpc/papr_hcalls.rst +++ b/Documentation/powerpc/papr_hcalls.rst @@ -275,6 +275,20 @@ Health Bitmap Flags: Given a DRC Index collect the performance statistics for NVDIMM and copy them to the resultBuffer. +**H_SCM_FLUSH** + +| Input: *drcIndex, continue-token* +| Out: *continue-token* +| Return Value: *H_SUCCESS, H_Parameter, H_P2, H_BUSY* + +Given a DRC Index Flush the data to backend NVDIMM device. + +The hcall returns H_BUSY when the flush takes longer time and the hcall needs +to be issued multiple times in order to be completely serviced. The +*continue-token* from the output to be passed in the argument list of +subsequent hcalls to the hypervisor until the hcall is completely serviced +at which point H_SUCCESS or other error is returned by the hypervisor. + References ========== .. [1] "Power Architecture Platform Reference" -- cgit v1.2.3