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 OMAP List <linux-omap@vger.kernel.org>,
Linux ARM Kernel List <linux-arm-kernel@lists.infradead.org>,
Linux DaVinci Kernel List
<davinci-linux-open-source@linux.davincidsp.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux MMC List <linux-mmc@vger.kernel.org>,
Joel Fernandes <joelf@ti.com>
Subject: [PATCH 6/9] dma: edma: Detect null slot errors and handle them correctly
Date: Mon, 29 Jul 2013 08:29:52 -0500 [thread overview]
Message-ID: <1375104595-16018-7-git-send-email-joelf@ti.com> (raw)
In-Reply-To: <1375104595-16018-1-git-send-email-joelf@ti.com>
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 <joelf@ti.com>
---
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
next prev 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 ` Joel Fernandes [this message]
2013-07-29 13:29 ` [PATCH 7/9] ARM: edma: Don't clear EMR of channel in edma_stop Joel Fernandes
[not found] ` <1375104595-16018-8-git-send-email-joelf-l0cyMroinI0@public.gmane.org>
2013-07-30 8:29 ` 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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