Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755294Ab3G2Nbx (ORCPT ); Mon, 29 Jul 2013 09:31:53 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:41187 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754193Ab3G2NbA (ORCPT ); Mon, 29 Jul 2013 09:31:00 -0400 From: Joel Fernandes To: Tony Lindgren , Sekhar Nori , Santosh Shilimkar , Sricharan R , Rajendra Nayak , Lokesh Vutla , Matt Porter , Grant Likely , Rob Herring , Vinod Koul , Dan Williams , Mark Brown , Benoit Cousson , Russell King , Arnd Bergmann , Olof Johansson , Balaji TK , Gururaja Hebbar , Chris Ball , Jason Kridner CC: Linux OMAP List , Linux ARM Kernel List , Linux DaVinci Kernel List , Linux Kernel Mailing List , Linux MMC List , Joel Fernandes Subject: [PATCH 6/9] dma: edma: Detect null slot errors and handle them correctly Date: Mon, 29 Jul 2013 08:29:52 -0500 Message-ID: <1375104595-16018-7-git-send-email-joelf@ti.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1375104595-16018-1-git-send-email-joelf@ti.com> References: <1375104595-16018-1-git-send-email-joelf@ti.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3730 Lines: 109 For crypto IP, we continue to receive events even continuously in NULL slot, and request lines don't get de-asserted unlike omap_hsmmc. Due to this, we continously receive error interrupts when we manually trigger an event. We fix this, by first detecting if the Channel is currently transferring from a NULL slot or not, that's where the edma_read_slot in the error callback from interrupt handler comes in. Second thing we do is, if we detect if we are on a NULL slot, we don't forcefully trigger as this will only result in more error conditions. Instead we set a missed flag and allow the manual triggerring to happen in edma_execute which will eventually be called. This fixes the issue where we are on a NULL slot and continue to receive events from modules like crypto that don't stop their request events after a transfer is completed. Signed-off-by: Joel Fernandes --- drivers/dma/edma.c | 42 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-) diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index 1eda5cc..c72e8c9 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -70,6 +70,7 @@ struct edma_chan { int ch_num; bool alloced; int slot[EDMA_MAX_SLOTS]; + int missed; struct dma_slave_config cfg; }; @@ -169,6 +170,18 @@ static void edma_execute(struct edma_chan *echan) dev_dbg(dev, "first transfer starting %d\n", echan->ch_num); edma_start(echan->ch_num); } + + /* This happens due to setup times between intermediate transfers + in long SG lists which have to be broken up into transfers of + MAX_NR_SG */ + if (echan->missed) { + dev_dbg(dev, "missed event in execute detected\n"); + edma_clean_channel(echan->ch_num); + edma_stop(echan->ch_num); + edma_start(echan->ch_num); + edma_manual_trigger(echan->ch_num); + echan->missed = 0; + } } static int edma_terminate_all(struct edma_chan *echan) @@ -387,6 +400,7 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data) struct device *dev = echan->vchan.chan.device->dev; struct edma_desc *edesc; unsigned long flags; + struct edmacc_param p; /* Pause the channel */ edma_pause(echan->ch_num); @@ -414,15 +428,35 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data) break; case DMA_CC_ERROR: - if (echan->edesc) { - dev_dbg(dev, "Missed event on %d, retrying\n", - ch_num); + spin_lock_irqsave(&echan->vchan.lock, flags); + + edma_read_slot(EDMA_CHAN_SLOT(echan->slot[0]), &p); + + if (p.a_b_cnt == 0 && p.ccnt == 0) { + dev_dbg(dev, "Error occurred, looks like slot is null, just setting miss\n"); + /* + Issue later based on missed flag which will be sure + to happen as: + (1) we finished transmitting an intermediate slot and + edma_execute is coming up. + (2) or we finished current transfer and issue will + call edma_execute. + + Important note: issuing can be dangerous here and + lead to some nasty recursion as this is a NULL slot + at this point. + */ + echan->missed = 1; + } else { + dev_dbg(dev, "Error occurred but slot is non-null, TRIGGERING\n"); edma_clean_channel(echan->ch_num); edma_stop(echan->ch_num); edma_start(echan->ch_num); edma_manual_trigger(echan->ch_num); } - dev_dbg(dev, "handled error on channel %d\n", ch_num); + + spin_unlock_irqrestore(&echan->vchan.lock, flags); + break; default: break; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/