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From: Tony Lindgren <tony@atomide.com>
To: linux-arm-kernel@lists.arm.linux.org.uk
Cc: Nishant Kamat <nskamat@ti.com>,
	linux-omap@vger.kernel.org,
	Santosh Shilimkar <santosh.shilimkar@ti.com>
Subject: [PATCH 6/7] ARM: OMAP: Dispatch only relevant DMA interrupts
Date: Wed, 04 Mar 2009 13:54:55 -0800	[thread overview]
Message-ID: <20090304215455.21101.47444.stgit@localhost> (raw)
In-Reply-To: <20090304214540.21101.72079.stgit@localhost>

From: Santosh Shilimkar <santosh.shilimkar@ti.com>

This fixes the spurious interrupt issue on a DMA channel.

In OMAP sDMA, contrast to the SDMA.DMA4_CSRi registers, the
SDMA.DMA4_IRQSTATUS_Lj registers are updated regardless of
the corresponding bits in the SDMA.DMA4_IRQENABLE_Lj registers.
Since there are four sDMA interrupt lines and if more than one
line is actively used by two concurrently running sDMA softwares
modules,then the spurious interrupt can be observed on the other
lines.

Fix in this patch will only dispatch the relevant and enabled
interrupts on a particular line thus perevting spurious IRQ.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Nishant Kamat <nskamat@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 arch/arm/plat-omap/dma.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index eca43bb..c46e5a4 100644
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -1901,7 +1901,7 @@ static int omap2_dma_handle_ch(int ch)
 /* STATUS register count is from 1-32 while our is 0-31 */
 static irqreturn_t omap2_dma_irq_handler(int irq, void *dev_id)
 {
-	u32 val;
+	u32 val, enable_reg;
 	int i;
 
 	val = dma_read(IRQSTATUS_L0);
@@ -1910,6 +1910,8 @@ static irqreturn_t omap2_dma_irq_handler(int irq, void *dev_id)
 			printk(KERN_WARNING "Spurious DMA IRQ\n");
 		return IRQ_HANDLED;
 	}
+	enable_reg = dma_read(IRQENABLE_L0);
+	val &= enable_reg; /* Dispatch only relevant interrupts */
 	for (i = 0; i < dma_lch_count && val != 0; i++) {
 		if (val & 1)
 			omap2_dma_handle_ch(i);


  parent reply	other threads:[~2009-03-04 21:54 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-04 21:47 [PATCH 0/7] Updates for common omap code for next merge window Tony Lindgren
2009-03-04 21:48 ` [PATCH 1/7] ARM: OMAP: Export dmtimer functions Tony Lindgren
2009-03-04 21:49 ` [PATCH 2/7] ARM: OMAP: Add documentation for function omap_register_i2c_bus Tony Lindgren
2009-03-04 21:51 ` [PATCH 3/7] ARM: OMAP: Add command line option for I2C bus speed Tony Lindgren
2009-03-05 16:20   ` Tony Lindgren
2009-03-05 19:37     ` Felipe Balbi
2009-03-06  7:13     ` Jarkko Nikula
2009-03-06 16:13       ` Tony Lindgren
     [not found]         ` <20090306161349.GC32353-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
2009-03-10  8:47           ` [2.6.29-rc7][take #2][PATCH 0/3] " Jarkko Nikula
     [not found]             ` <1236674831-3637-1-git-send-email-jarkko.nikula-xNZwKgViW5gAvxtiuMwx3w@public.gmane.org>
2009-03-10  8:47               ` [2.6.29-rc7][take #2][PATCH 1/3] ARM: OMAP: Add documentation for function omap_register_i2c_bus Jarkko Nikula
2009-03-10  8:47                 ` [2.6.29-rc7][take #2][PATCH 2/3] ARM: OMAP: Add command line option for I2C bus speed Jarkko Nikula
     [not found]                   ` <1236674831-3637-3-git-send-email-jarkko.nikula-xNZwKgViW5gAvxtiuMwx3w@public.gmane.org>
2009-03-10  8:47                     ` [2.6.29-rc7][take #2][PATCH 3/3] ARM: OMAP: Add method to register additional I2C busses on the command line Jarkko Nikula
2009-03-16 17:29                     ` [2.6.29-rc7][take #2][PATCH 2/3] ARM: OMAP: Add command line option for I2C bus speed Tony Lindgren
     [not found]                       ` <20090316172908.GA19229-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
2009-03-17  8:24                         ` Jarkko Nikula
2009-03-18 19:30         ` [PATCH 3/7] " Russell King - ARM Linux
2009-03-19 11:22           ` Jarkko Nikula
2009-03-04 21:52 ` [PATCH 4/7] ARM: OMAP: Add method to register additional I2C busses on the command line Tony Lindgren
2009-03-04 21:53 ` [PATCH 5/7] ARM: OMAP: Get available DMA channels from cmdline Tony Lindgren
2009-03-04 21:54 ` Tony Lindgren [this message]
2009-03-04 21:56 ` [PATCH 7/7] ARM: OMAP: get rid of OMAP_TAG_USB Tony Lindgren
2009-03-11 16:31   ` [PATCH 7/7] ARM: OMAP: get rid of OMAP_TAG_USB, v2 Tony Lindgren
2009-03-16 17:31 ` [PATCH 0/7] Updates for common omap code for next merge window Tony Lindgren

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