diff mbox

[V2,1/2] ARM: OMAP2+: DMA: remove requirement of irq for platform-dma driver

Message ID 1402573523-13814-2-git-send-email-r.sricharan@ti.com
State Accepted
Commit 76be4a54157ab0059fb29d8d516db46d239812e2
Headers show

Commit Message

Sricharan R June 12, 2014, 11:45 a.m. UTC 
From: Nishanth Menon <nm@ti.com>

we have currently 2 DMA drivers that try to co-exist.
drivers/dma/omap-dma.c which registers it's own IRQ and is device tree
aware and uses arch/arm/plat-omap/dma.c instance created by
arch/arm/mach-omap2/dma.c to maintain channel usage (omap_request_dma).

Currently both try to register interrupts and mach-omap2/plat-omap dma.c
attempts to use the IRQ number registered by hwmod to register it's own
interrupt handler.

Now, there is no reasonable way of static allocating DMA irq in GIC
SPI when we use crossbar. However, since the dma_chan structure is
freed as a result of IRQ not being present due to devm allocation,
maintaining information of channel by platform code fails at a later
point in time when that region of memory is reused.

So, if hwmod does not indicate an IRQ number, then, assume that
dma-engine will take care of the interrupt handling.

Signed-off-by: Nishanth Menon <nm@ti.com>
---
 arch/arm/mach-omap2/dma.c |    3 +++
 arch/arm/plat-omap/dma.c  |    5 +++--
 include/linux/omap-dma.h  |    1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

Comments

Tony Lindgren July 22, 2014, 6:37 a.m. UTC | #1 
* Sricharan R <r.sricharan@ti.com> [140612 04:48]:
> From: Nishanth Menon <nm@ti.com>
> 
> we have currently 2 DMA drivers that try to co-exist.
> drivers/dma/omap-dma.c which registers it's own IRQ and is device tree
> aware and uses arch/arm/plat-omap/dma.c instance created by
> arch/arm/mach-omap2/dma.c to maintain channel usage (omap_request_dma).
> 
> Currently both try to register interrupts and mach-omap2/plat-omap dma.c
> attempts to use the IRQ number registered by hwmod to register it's own
> interrupt handler.
> 
> Now, there is no reasonable way of static allocating DMA irq in GIC
> SPI when we use crossbar. However, since the dma_chan structure is
> freed as a result of IRQ not being present due to devm allocation,
> maintaining information of channel by platform code fails at a later
> point in time when that region of memory is reused.
> 
> So, if hwmod does not indicate an IRQ number, then, assume that
> dma-engine will take care of the interrupt handling.

Looks OK to me, applying both into omap-for-v3.17/soc thanks.

Regards,

Tony
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diff mbox

Patch

diff --git a/arch/arm/mach-omap2/dma.c b/arch/arm/mach-omap2/dma.c
index a6d2cf1..e1a56d8 100644
--- a/arch/arm/mach-omap2/dma.c
+++ b/arch/arm/mach-omap2/dma.c
@@ -259,6 +259,9 @@  static int __init omap2_system_dma_init_dev(struct omap_hwmod *oh, void *unused)
 	if (cpu_is_omap34xx() && (omap_type() != OMAP2_DEVICE_TYPE_GP))
 		d->dev_caps |= HS_CHANNELS_RESERVED;
 
+	if (platform_get_irq_byname(pdev, "0") < 0)
+		d->dev_caps |= DMA_ENGINE_HANDLE_IRQ;
+
 	/* Check the capabilities register for descriptor loading feature */
 	if (dma_read(CAPS_0, 0) & DMA_HAS_DESCRIPTOR_CAPS)
 		dma_common_ch_end = CCDN;
diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index b5608b1..7aae0e5 100644
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -2100,7 +2100,7 @@  static int omap_system_dma_probe(struct platform_device *pdev)
 		omap_dma_set_global_params(DMA_DEFAULT_ARB_RATE,
 				DMA_DEFAULT_FIFO_DEPTH, 0);
 
-	if (dma_omap2plus()) {
+	if (dma_omap2plus() && !(d->dev_caps & DMA_ENGINE_HANDLE_IRQ)) {
 		strcpy(irq_name, "0");
 		dma_irq = platform_get_irq_byname(pdev, irq_name);
 		if (dma_irq < 0) {
@@ -2145,7 +2145,8 @@  static int omap_system_dma_remove(struct platform_device *pdev)
 		char irq_name[4];
 		strcpy(irq_name, "0");
 		dma_irq = platform_get_irq_byname(pdev, irq_name);
-		remove_irq(dma_irq, &omap24xx_dma_irq);
+		if (dma_irq >= 0)
+			remove_irq(dma_irq, &omap24xx_dma_irq);
 	} else {
 		int irq_rel = 0;
 		for ( ; irq_rel < dma_chan_count; irq_rel++) {
diff --git a/include/linux/omap-dma.h b/include/linux/omap-dma.h
index 88e6ea4..6f06f8b 100644
--- a/include/linux/omap-dma.h
+++ b/include/linux/omap-dma.h
@@ -130,6 +130,7 @@ 
 #define IS_WORD_16			BIT(0xd)
 #define ENABLE_16XX_MODE		BIT(0xe)
 #define HS_CHANNELS_RESERVED		BIT(0xf)
+#define DMA_ENGINE_HANDLE_IRQ		BIT(0x10)
 
 /* Defines for DMA Capabilities */
 #define DMA_HAS_TRANSPARENT_CAPS	(0x1 << 18)