Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758957AbcCVLVi (ORCPT ); Tue, 22 Mar 2016 07:21:38 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56406 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758656AbcCVKll (ORCPT ); Tue, 22 Mar 2016 06:41:41 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Andy Shevchenko , Vinod Koul , Luis Henriques Subject: [PATCH 3.16.y-ckt 016/142] dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer Date: Tue, 22 Mar 2016 10:39:05 +0000 Message-Id: <1458643271-4227-17-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1458643271-4227-1-git-send-email-luis.henriques@canonical.com> References: <1458643271-4227-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2906 Lines: 84 3.16.7-ckt26 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Andy Shevchenko commit ee1cdcdae59563535485a5f56ee72c894ab7d7ad upstream. The commit 2895b2cad6e7 ("dmaengine: dw: fix cyclic transfer callbacks") re-enabled BLOCK interrupts with regard to make cyclic transfers work. However, this change becomes a regression for non-cyclic transfers as interrupt counters under stress test had been grown enormously (approximately per 4-5 bytes in the UART loop back test). Taking into consideration above enable BLOCK interrupts if and only if channel is programmed to perform cyclic transfer. Fixes: 2895b2cad6e7 ("dmaengine: dw: fix cyclic transfer callbacks") Signed-off-by: Andy Shevchenko Acked-by: Mans Rullgard Tested-by: Mans Rullgard Acked-by: Viresh Kumar Signed-off-by: Vinod Koul Signed-off-by: Luis Henriques --- drivers/dma/dw/core.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c index e968366e6cdd..43c8de0f00f4 100644 --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -169,7 +169,6 @@ static void dwc_initialize(struct dw_dma_chan *dwc) /* Enable interrupts */ channel_set_bit(dw, MASK.XFER, dwc->mask); - channel_set_bit(dw, MASK.BLOCK, dwc->mask); channel_set_bit(dw, MASK.ERROR, dwc->mask); dwc->initialized = true; @@ -596,6 +595,9 @@ static void dwc_handle_cyclic(struct dw_dma *dw, struct dw_dma_chan *dwc, spin_unlock_irqrestore(&dwc->lock, flags); } + + /* Re-enable interrupts */ + channel_set_bit(dw, MASK.BLOCK, dwc->mask); } /* ------------------------------------------------------------------------- */ @@ -626,11 +628,8 @@ static void dw_dma_tasklet(unsigned long data) dwc_scan_descriptors(dw, dwc); } - /* - * Re-enable interrupts. - */ + /* Re-enable interrupts */ channel_set_bit(dw, MASK.XFER, dw->all_chan_mask); - channel_set_bit(dw, MASK.BLOCK, dw->all_chan_mask); channel_set_bit(dw, MASK.ERROR, dw->all_chan_mask); } @@ -1216,6 +1215,7 @@ static void dwc_free_chan_resources(struct dma_chan *chan) int dw_dma_cyclic_start(struct dma_chan *chan) { struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_dma *dw = to_dw_dma(chan->device); unsigned long flags; if (!test_bit(DW_DMA_IS_CYCLIC, &dwc->flags)) { @@ -1224,7 +1224,12 @@ int dw_dma_cyclic_start(struct dma_chan *chan) } spin_lock_irqsave(&dwc->lock, flags); + + /* Enable interrupts to perform cyclic transfer */ + channel_set_bit(dw, MASK.BLOCK, dwc->mask); + dwc_dostart(dwc, dwc->cdesc->desc[0]); + spin_unlock_irqrestore(&dwc->lock, flags); return 0;