Re: [PATCH 2/7] net: ethernet: ti: cpdma: fix desc re-queuing
flat view
From: Ivan Khoronzhuk <hidden>
Date: 2016-12-02 11:03:29
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linux-omap, lkml
On Thu, Dec 01, 2016 at 05:34:27PM -0600, Grygorii Strashko wrote:
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;
It shouldn't happen in normal circumstances, right? So, why it happens only for egress channels? And Does that mean there is some resynchronization between submit and process function, or this is h/w issue?
quoted hunk ↗ jump to hunk
- 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