slw: do SLW timer testing while holding xscom lock

We add some routines that let a caller get the xscom lock once and
then do a bunch of xscoms while holding it.

In some situations without this, it could take long enough to get
the xscom lock that the 1ms timeout would expire and we'd falsely
think the SLW timer didn't work when in fact it did.

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/hw/slw.c b/hw/slw.c
index b4fb6ec2..32481fb2 100644
--- a/hw/slw.c
+++ b/hw/slw.c
@@ -1242,11 +1242,13 @@ void slw_update_timer_expiry(uint64_t new_target)
 
 	do {
 		/* Grab generation and spin if odd */
+		_xscom_lock();
 		for (;;) {
-			rc = xscom_read(slw_timer_chip, 0xE0006, &gen);
+			rc = _xscom_read(slw_timer_chip, 0xE0006, &gen, false);
 			if (rc) {
 				prerror("SLW: Error %lld reading tmr gen "
 					" count\n", rc);
+				_xscom_unlock();
 				return;
 			}
 			if (!(gen & 1))
@@ -1271,25 +1273,29 @@ void slw_update_timer_expiry(uint64_t new_target)
 				 */
 				prerror("SLW: timer stuck, falling back to OPAL pollers. You will likely have slower I2C and may have experienced increased jitter.\n");
 				prlog(PR_DEBUG, "SLW: Stuck with odd generation !\n");
+				_xscom_unlock();
 				slw_has_timer = false;
 				slw_dump_timer_ffdc();
 				return;
 			}
 		}
 
-		rc = xscom_write(slw_timer_chip, 0x5003A, req);
+		rc = _xscom_write(slw_timer_chip, 0x5003A, req, false);
 		if (rc) {
 			prerror("SLW: Error %lld writing tmr request\n", rc);
+			_xscom_unlock();
 			return;
 		}
 
 		/* Re-check gen count */
-		rc = xscom_read(slw_timer_chip, 0xE0006, &gen2);
+		rc = _xscom_read(slw_timer_chip, 0xE0006, &gen2, false);
 		if (rc) {
 			prerror("SLW: Error %lld re-reading tmr gen "
 				" count\n", rc);
+			_xscom_unlock();
 			return;
 		}
+		_xscom_unlock();
 	} while(gen != gen2);
 
 	/* Check if the timer is working. If at least 1ms has elapsed