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From: Grygorii Strashko <grygorii.strashko@ti.com>
To: "David S. Miller" <davem@davemloft.net>,
	netdev@vger.kernel.org, Mugunthan V N <mugunthanvnm@ti.com>
Cc: Sekhar Nori <nsekhar@ti.com>,
	linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org,
	Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>,
	Grygorii Strashko <grygorii.strashko@ti.com>
Subject: [PATCH 2/7] net: ethernet: ti: cpdma: fix desc re-queuing
Date: Thu, 1 Dec 2016 17:34:27 -0600	[thread overview]
Message-ID: <20161201233432.6182-3-grygorii.strashko@ti.com> (raw)
In-Reply-To: <20161201233432.6182-1-grygorii.strashko@ti.com>

The currently processing cpdma descriptor with EOQ flag set may
contain two values in Next Descriptor Pointer field:
- valid pointer: means CPDMA missed addition of new desc in queue;
- null: no more descriptors in queue.
In the later case, it's not required to write to HDP register, but now
CPDMA does it.

Hence, add additional check for Next Descriptor Pointer != null in
cpdma_chan_process() function before writing in HDP register.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
---
 drivers/net/ethernet/ti/davinci_cpdma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c
index 0924014..379314f 100644
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -1152,7 +1152,7 @@ static int __cpdma_chan_process(struct cpdma_chan *chan)
 	chan->count--;
 	chan->stats.good_dequeue++;
 
-	if (status & CPDMA_DESC_EOQ) {
+	if ((status & CPDMA_DESC_EOQ) && chan->head) {
 		chan->stats.requeue++;
 		chan_write(chan, hdp, desc_phys(pool, chan->head));
 	}
-- 
2.10.1

  parent reply	other threads:[~2016-12-01 23:34 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-01 23:34 [PATCH 0/7] net: ethernet: ti: cpsw: support placing CPDMA descriptors into DDR Grygorii Strashko
2016-12-01 23:34 ` [PATCH 1/7] net: ethernet: ti: cpdma: am437x: allow descs to be plased in ddr Grygorii Strashko
2016-12-03 20:34   ` David Miller
2016-12-05 17:57     ` Grygorii Strashko
2016-12-01 23:34 ` Grygorii Strashko [this message]
2016-12-02 11:03   ` [PATCH 2/7] net: ethernet: ti: cpdma: fix desc re-queuing Ivan Khoronzhuk
2016-12-02 16:45     ` Grygorii Strashko
2016-12-02 23:28       ` Ivan Khoronzhuk
2016-12-05 18:22         ` Grygorii Strashko
2016-12-01 23:34 ` [PATCH 3/7] net: ethernet: ti: cpdma: minimize number of parameters in cpdma_desc_pool_create/destroy() Grygorii Strashko
2016-12-01 23:34 ` [PATCH 4/7] net: ethernet: ti: cpdma: use devm_ioremap Grygorii Strashko
2016-12-01 23:34 ` [PATCH 5/7] Documentation: DT: net: cpsw: allow to specify descriptors pool size Grygorii Strashko
2016-12-02 11:28   ` Ivan Khoronzhuk
2016-12-02 17:21     ` Grygorii Strashko
2016-12-07 19:41       ` Grygorii Strashko
2016-12-02 17:22     ` Grygorii Strashko
2016-12-01 23:34 ` [PATCH 6/7] net: ethernet: ti: cpsw: add support for descs_pool_size dt property Grygorii Strashko
2016-12-01 23:34 ` [PATCH 7/7] Documentation: DT: net: cpsw: remove no_bd_ram property Grygorii Strashko

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