[PATCH Wily SRU v2] cxl: Fix PSL timebase synchronization detection

[tim.gardner at canonical.com]

From: Frederic Barrat <fbarrat at linux.vnet.ibm.com>

BugLink: http://bugs.launchpad.net/bugs/1532914

The PSL timebase synchronization is seemingly failing for
configuration not including VIRT_CPU_ACCOUNTING_NATIVE. The driver
shows the following trace in dmesg:
PSL: Timebase sync: giving up!

The PSL timebase register is actually syncing correctly, but the cxl
driver is not detecting it. Fix is to use the proper timebase-to-time
conversion.

Signed-off-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>
Cc: <stable at vger.kernel.org> # 4.3+
Acked-by: Michael Neuling <mikey at neuling.org>
Reviewed-by: Matthew R. Ochs <mrochs at linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie at au1.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
Reviewed-by: Vaibhav Jain <vaibhav at linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
(cherry picked from git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git commit 923adb1646d5ba739d2a1e63ee20d60574d9da8e)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 drivers/misc/cxl/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index 4c1903f..0c6c17a1 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -415,7 +415,7 @@ static int cxl_setup_psl_timebase(struct cxl *adapter, struct pci_dev *dev)
 		delta = mftb() - psl_tb;
 		if (delta < 0)
 			delta = -delta;
-	} while (cputime_to_usecs(delta) > 16);
+	} while (tb_to_ns(delta) > 16000);
 
 	return 0;
 }
-- 
1.9.1