commit: 3670e7e12e582c6d67761275d148171feb7a9004
From: Alexandre Bounine <[email protected]>
Date: Tue, 21 Aug 2012 16:16:11 -0700
Subject: 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]>
---
 drivers/rapidio/devices/tsi721.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/rapidio/devices/tsi721.c b/drivers/rapidio/devices/tsi721.c
index 722246c..c0d6a04 100644
--- 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);
 }
 
 /**
-- 
1.7.3.4
--
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