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From: Joel Fernandes <joelf@ti.com>
To: Tony Lindgren <tony@atomide.com>, Sekhar Nori <nsekhar@ti.com>,
	Santosh Shilimkar <santosh.shilimkar@ti.com>,
	Sricharan R <r.sricharan@ti.com>, Rajendra Nayak <rnayak@ti.com>,
	Lokesh Vutla <lokeshvutla@ti.com>,
	Matt Porter <matt@ohporter.com>,
	Grant Likely <grant.likely@secretlab.ca>,
	Rob Herring <rob.herring@calxeda.com>,
	Vinod Koul <vinod.koul@intel.com>, Dan Williams <djbw@fb.com>,
	Mark Brown <broonie@linaro.org>,
	Benoit Cousson <benoit.cousson@linaro.org>,
	Russell King <linux@arm.linux.org.uk>,
	Arnd Bergmann <arnd@arndb.de>, Olof Johansson <olof@lixom.net>,
	Balaji TK <balajitk@ti.com>,
	Gururaja Hebbar <gururaja.hebbar@ti.com>,
	Chris Ball <cjb@laptop.org>,
	Jason Kridner <jkridner@beagleboard.org>
Cc: Linux DaVinci Kernel List
	<davinci-linux-open-source@linux.davincidsp.com>,
	Joel Fernandes <joelf@ti.com>,
	Linux MMC List <linux-mmc@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux OMAP List <linux-omap@vger.kernel.org>,
	Linux ARM Kernel List <linux-arm-kernel@lists.infradead.org>
Subject: [PATCH 7/9] ARM: edma: Don't clear EMR of channel in edma_stop
Date: Mon, 29 Jul 2013 08:29:53 -0500	[thread overview]
Message-ID: <1375104595-16018-8-git-send-email-joelf@ti.com> (raw)
In-Reply-To: <1375104595-16018-1-git-send-email-joelf@ti.com>

We certainly don't want error conditions to be cleared anywhere
as this will make us 'forget' about missed events. We depend on
knowing which events were missed in order to be able to reissue them.

This fixes a race condition where the EMR was being cleared
by the transfer completion interrupt handler.

Basically, what was happening was:

            Missed event
             |
             |
             V
SG1-SG2-SG3-Null
         \
          \__TC Interrupt (Almost same time as ARM is executing
TC interrupt handler, an event got missed and also forgotten
by clearing the EMR).

The EMR is ultimately being cleared by the Error interrupt
handler once it is handled so we don't have to do it in edma_stop.

Signed-off-by: Joel Fernandes <joelf@ti.com>
---
 arch/arm/common/edma.c |    1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c
index 10995b2..dec772e 100644
--- a/arch/arm/common/edma.c
+++ b/arch/arm/common/edma.c
@@ -1328,7 +1328,6 @@ void edma_stop(unsigned channel)
 		edma_shadow0_write_array(ctlr, SH_EECR, j, mask);
 		edma_shadow0_write_array(ctlr, SH_ECR, j, mask);
 		edma_shadow0_write_array(ctlr, SH_SECR, j, mask);
-		edma_write_array(ctlr, EDMA_EMCR, j, mask);
 
 		pr_debug("EDMA: EER%d %08x\n", j,
 				edma_shadow0_read_array(ctlr, SH_EER, j));
-- 
1.7.9.5

  parent reply	other threads:[~2013-07-29 13:29 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-29 13:29 [PATCH 0/9] dma: edma: Support scatter-lists of any length Joel Fernandes
     [not found] ` <1375104595-16018-1-git-send-email-joelf-l0cyMroinI0@public.gmane.org>
2013-07-29 13:29   ` [PATCH 1/9] dma: edma: Setup parameters to DMA MAX_NR_SG at a time Joel Fernandes
2013-07-29 13:29   ` [PATCH 2/9] dma: edma: Write out and handle MAX_NR_SG at a given time Joel Fernandes
2013-07-29 13:29   ` [PATCH 3/9] ARM: edma: Add function to manually trigger an EDMA channel Joel Fernandes
     [not found]     ` <1375104595-16018-4-git-send-email-joelf-l0cyMroinI0@public.gmane.org>
2013-07-30  5:18       ` Sekhar Nori
     [not found]         ` <51F74CAD.3040604-l0cyMroinI0@public.gmane.org>
2013-07-31  4:30           ` Joel Fernandes
     [not found]             ` <51F892D2.4090805-l0cyMroinI0@public.gmane.org>
2013-07-31  5:23               ` Sekhar Nori
     [not found]                 ` <51F89F5E.2050605-l0cyMroinI0@public.gmane.org>
2013-07-31  5:34                   ` Fernandes, Joel
2013-07-29 13:29 ` [PATCH 4/9] dma: edma: Find missed events and issue them Joel Fernandes
     [not found]   ` <1375104595-16018-5-git-send-email-joelf-l0cyMroinI0@public.gmane.org>
2013-07-30  7:05     ` Sekhar Nori
     [not found]       ` <51F7659E.3040302-l0cyMroinI0@public.gmane.org>
2013-07-31  4:49         ` Joel Fernandes
     [not found]           ` <51F89763.1010102-l0cyMroinI0@public.gmane.org>
2013-07-31  9:18             ` Sekhar Nori
     [not found]               ` <51F8D667.2040406-l0cyMroinI0@public.gmane.org>
2013-08-01  2:27                 ` Joel Fernandes
     [not found]                   ` <51F9C793.2000001-l0cyMroinI0@public.gmane.org>
2013-08-01  3:43                     ` Joel Fernandes
2013-08-01  4:39                     ` Joel Fernandes
2013-08-01  6:13                     ` Sekhar Nori
     [not found]                       ` <51F9FC87.3020706-l0cyMroinI0@public.gmane.org>
2013-08-01 20:28                         ` Joel Fernandes
     [not found]                           ` <51FAC50A.2020507-l0cyMroinI0@public.gmane.org>
2013-08-01 20:48                             ` Joel Fernandes
2013-08-02 13:26                             ` Sekhar Nori
     [not found]                               ` <51FBB371.6030901-l0cyMroinI0@public.gmane.org>
2013-08-02 18:15                                 ` Joel Fernandes
     [not found]                                   ` <51FBF749.4010303-l0cyMroinI0@public.gmane.org>
2013-08-02 23:00                                     ` Joel Fernandes
2013-07-29 13:29 ` [PATCH 5/9] dma: edma: Leave linked to Null slot instead of DUMMY slot Joel Fernandes
2013-07-29 13:29 ` [PATCH 6/9] dma: edma: Detect null slot errors and handle them correctly Joel Fernandes
2013-07-29 13:29 ` Joel Fernandes [this message]
     [not found]   ` <1375104595-16018-8-git-send-email-joelf-l0cyMroinI0@public.gmane.org>
2013-07-30  8:29     ` [PATCH 7/9] ARM: edma: Don't clear EMR of channel in edma_stop Sekhar Nori
     [not found]       ` <51F77982.7030601-l0cyMroinI0@public.gmane.org>
2013-07-31  5:05         ` Joel Fernandes
     [not found]           ` <51F89B0B.4080803-l0cyMroinI0@public.gmane.org>
2013-07-31  9:35             ` Sekhar Nori
     [not found]               ` <51F8DA5C.9060503-l0cyMroinI0@public.gmane.org>
2013-08-01  1:59                 ` Joel Fernandes
2013-07-29 13:29 ` [PATCH 8/9] dma: edma: Link to dummy slot only for last SG list split Joel Fernandes
2013-07-29 13:29 ` [PATCH 9/9] dma: edma: remove limits on number of slots Joel Fernandes

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