From mboxrd@z Thu Jan 1 00:00:00 1970 From: vinod.koul@intel.com (Vinod Koul) Date: Mon, 21 Nov 2011 14:02:06 +0530 Subject: [PATCH v2 1/5] dmaengine: add ep93xx DMA support In-Reply-To: <20111121080158.GA2713@mwesterb-mobl.ger.corp.intel.com> References: <3ea8d56034f25cbe3fd8a4c31d7d0d1540b6ac7e.1306662317.git.mika.westerberg@iki.fi> <4EC27EED.4030108@metasoft.pl> <20111116065512.GB2703@mwesterb-mobl.ger.corp.intel.com> <4EC374F0.8000400@metasoft.pl> <20111119123837.GA2711@mwesterb-mobl.ger.corp.intel.com> <4ECA0147.4020806@metasoft.pl> <20111121080158.GA2713@mwesterb-mobl.ger.corp.intel.com> Message-ID: <1321864326.1516.211.camel@vkoul-udesk3> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 2011-11-21 at 10:01 +0200, Mika Westerberg wrote: > On Mon, Nov 21, 2011 at 08:44:07AM +0100, Rafal Prylowski wrote: > > > > I'm calling dma_terminate_all from interrupt. It seems that tasklet_kill is not > > allowed to be called from this context. > > Ah, right. > > One more try - this time we set a flag which prevents the tasktlet from > referencing an empty list. Rather than this why not actually check for list_empty and process only when it is not empty? Also you should check the return of the ep93xx_dma_get_active() which should return NULL if it didn't find anything in active list > > diff --git a/drivers/dma/ep93xx_dma.c b/drivers/dma/ep93xx_dma.c > index 6181811..f7244b3 100644 > --- a/drivers/dma/ep93xx_dma.c > +++ b/drivers/dma/ep93xx_dma.c > @@ -155,6 +155,8 @@ struct ep93xx_dma_chan { > unsigned long flags; > /* Channel is configured for cyclic transfers */ > #define EP93XX_DMA_IS_CYCLIC 0 > +/* Channel is enabled */ > +#define EP93xx_DMA_IS_RUNNING 1 > > int buffer; > dma_cookie_t last_completed; > @@ -673,6 +675,9 @@ static void ep93xx_dma_tasklet(unsigned long data) > void *callback_param; > LIST_HEAD(list); > > + if (!test_bit(EP93XX_DMA_IS_RUNNING, &edmac->flags)) > + return; > + > spin_lock_irq(&edmac->lock); > desc = ep93xx_dma_get_active(edmac); > if (desc->complete) { > @@ -758,6 +763,8 @@ static dma_cookie_t ep93xx_dma_tx_submit(struct dma_async_tx_descriptor *tx) > edmac->chan.cookie = cookie; > desc->txd.cookie = cookie; > > + set_bit(EP93XX_DMA_IS_RUNNING, &edmac->flags); > + > /* > * If nothing is currently prosessed, we push this descriptor > * directly to the hardware. Otherwise we put the descriptor > @@ -1106,6 +1113,7 @@ static int ep93xx_dma_terminate_all(struct ep93xx_dma_chan *edmac) > spin_lock_irqsave(&edmac->lock, flags); > /* First we disable and flush the DMA channel */ > edmac->edma->hw_shutdown(edmac); > + clear_bit(EP93XX_DMA_IS_RUNNING, &edmac->flags); > clear_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags); > list_splice_init(&edmac->active, &list); > list_splice_init(&edmac->queue, &list); > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- ~Vinod