rapidio/tsi721: fix inbound doorbell interrupt handling

Make sure that there is no doorbell messages left behind due to disabled
interrupts during inbound doorbell processing.

The most common case for this bug is loss of rionet JOIN messages in
systems with three or more rionet participants and MSI or MSI-X enabled.
As result, requests for packet transfers may finish with "destination
unreachable" error message.

This patch is applicable to kernel versions starting from v3.2.

Signed-off-by: Alexandre Bounine <[email protected]>
Cc: Matt Porter <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/drivers/rapidio/devices/tsi721.c b/drivers/rapidio/devices/tsi721.c
index 722246cf20ab2ed592a6a5ed5435b0f1320a5a44..c0d6a049cbd69416c8f86afa674553a5ba30d21a 100644 (file)
--- a/drivers/rapidio/devices/tsi721.c
+++ b/drivers/rapidio/devices/tsi721.c
@@ -435,6 +435,9 @@ static void tsi721_db_dpc(struct work_struct *work)
                                " info %4.4x\n", DBELL_SID(idb.bytes),
                                DBELL_TID(idb.bytes), DBELL_INF(idb.bytes));
                }
+
+               wr_ptr = ioread32(priv->regs +
+                                 TSI721_IDQ_WP(IDB_QUEUE)) % IDB_QSIZE;
        }
 
        iowrite32(rd_ptr & (IDB_QSIZE - 1),
@@ -445,6 +448,10 @@ static void tsi721_db_dpc(struct work_struct *work)
        regval |= TSI721_SR_CHINT_IDBQRCV;
        iowrite32(regval,
                priv->regs + TSI721_SR_CHINTE(IDB_QUEUE));
+
+       wr_ptr = ioread32(priv->regs + TSI721_IDQ_WP(IDB_QUEUE)) % IDB_QSIZE;
+       if (wr_ptr != rd_ptr)
+               schedule_work(&priv->idb_work);
 }
 
 /**