From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: [PATCH v2 2/7] net: ethernet: ti: cpdma: fix desc re-queuing Date: Fri, 6 Jan 2017 14:07:30 -0600 Message-ID: <20170106200735.4210-3-grygorii.strashko@ti.com> References: <20170106200735.4210-1-grygorii.strashko@ti.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Sekhar Nori , , , Grygorii Strashko To: "David S. Miller" , , Mugunthan V N , Ivan Khoronzhuk Return-path: In-Reply-To: <20170106200735.4210-1-grygorii.strashko@ti.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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 --- 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 d6f0ded..a53b384 100644 --- a/drivers/net/ethernet/ti/davinci_cpdma.c +++ b/drivers/net/ethernet/ti/davinci_cpdma.c @@ -1159,7 +1159,7 @@ 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.dirty