Commit e2eca638 authored by Martin Sperl's avatar Martin Sperl Committed by Vinod Koul
Browse files

dmaengine: bcm2835: use platform_get_irq_byname 



Use platform_get_irq_byname to allow for correct mapping of
interrupts to dma channels.

The currently implemented device tree is unfortunately
implemented with the wrong assumption, that each dma-channel
has its own dma channel, but dma-irq 11 is handling
dma-channel 11-14 and dma-irq 12 is actually a "catch all"
interrupt.

So here we use the byname variant and require that interrupts
are explicitly named via the interrupts-name property in the
device tree.

The use of shared interrupts is also implemented.

As a side-effect this means we can now use dma channels 12, 13 and 14
in a correct manner - also testing shows that onl using
channels 11 to 14 for spi and i2s works perfectly (when playing
some video)

Signed-off-by: default avatarMartin Sperl <kernel@martin.sperl.org>
Acked-by: default avatarEric Anholt <eric@anholt.net>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent e7679db7

drivers/dma/bcm2835-dma.c

+63 −14
Original line number Diff line number Diff line
@@ -46,6 +46,9 @@ 


#include "virt-dma.h"



#define BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED 14

#define BCM2835_DMA_CHAN_NAME_SIZE 8



struct bcm2835_dmadev {

	struct dma_device ddev;

	spinlock_t lock;
@@ -81,6 +84,7 @@ struct bcm2835_chan { 


	void __iomem *chan_base;

	int irq_number;

	unsigned int irq_flags;



	bool is_lite_channel;

};
@@ -466,6 +470,15 @@ static irqreturn_t bcm2835_dma_callback(int irq, void *data) 
	struct bcm2835_desc *d;

	unsigned long flags;



	/* check the shared interrupt */

	if (c->irq_flags & IRQF_SHARED) {

		/* check if the interrupt is enabled */

		flags = readl(c->chan_base + BCM2835_DMA_CS);

		/* if not set then we are not the reason for the irq */

		if (!(flags & BCM2835_DMA_INT))

			return IRQ_NONE;

	}



	spin_lock_irqsave(&c->vc.lock, flags);



	/* Acknowledge interrupt */
@@ -506,8 +519,8 @@ static int bcm2835_dma_alloc_chan_resources(struct dma_chan *chan) 
		return -ENOMEM;

	}



	return request_irq(c->irq_number,

			bcm2835_dma_callback, 0, "DMA IRQ", c);

	return request_irq(c->irq_number, bcm2835_dma_callback,

			   c->irq_flags, "DMA IRQ", c);

}



static void bcm2835_dma_free_chan_resources(struct dma_chan *chan)
@@ -819,7 +832,8 @@ static int bcm2835_dma_terminate_all(struct dma_chan *chan) 
	return 0;

}



static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id, int irq)

static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id,

				 int irq, unsigned int irq_flags)

{

	struct bcm2835_chan *c;
@@ -834,6 +848,7 @@ static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id, int irq) 
	c->chan_base = BCM2835_DMA_CHANIO(d->base, chan_id);

	c->ch = chan_id;

	c->irq_number = irq;

	c->irq_flags = irq_flags;



	/* check in DEBUG register if this is a LITE channel */

	if (readl(c->chan_base + BCM2835_DMA_DEBUG) &
@@ -882,9 +897,11 @@ static int bcm2835_dma_probe(struct platform_device *pdev) 
	struct resource *res;

	void __iomem *base;

	int rc;

	int i;

	int irq;

	int i, j;

	int irq[BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED + 1];

	int irq_flags;

	uint32_t chans_available;

	char chan_name[BCM2835_DMA_CHAN_NAME_SIZE];



	if (!pdev->dev.dma_mask)

		pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
@@ -941,17 +958,49 @@ static int bcm2835_dma_probe(struct platform_device *pdev) 
		goto err_no_dma;

	}



	for (i = 0; i < pdev->num_resources; i++) {

		irq = platform_get_irq(pdev, i);

		if (irq < 0)

	/* get irqs for each channel that we support */

	for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) {

		/* skip masked out channels */

		if (!(chans_available & (1 << i))) {

			irq[i] = -1;

			continue;

		}



		/* get the named irq */

		snprintf(chan_name, sizeof(chan_name), "dma%i", i);

		irq[i] = platform_get_irq_byname(pdev, chan_name);

		if (irq[i] >= 0)

			continue;



		/* legacy device tree case handling */

		dev_warn_once(&pdev->dev,

			      "missing interrupts-names property in device tree - legacy interpretation is used");

		/*

		 * in case of channel >= 11

		 * use the 11th interrupt and that is shared

		 */

		irq[i] = platform_get_irq(pdev, i < 11 ? i : 11);

	}



	/* get irqs for each channel */

	for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) {

		/* skip channels without irq */

		if (irq[i] < 0)

			continue;



		/* check if there are other channels that also use this irq */

		irq_flags = 0;

		for (j = 0; j <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; j++)

			if ((i != j) && (irq[j] == irq[i])) {

				irq_flags = IRQF_SHARED;

				break;

			}



		if (chans_available & (1 << i)) {

			rc = bcm2835_dma_chan_init(od, i, irq);

		/* initialize the channel */

		rc = bcm2835_dma_chan_init(od, i, irq[i], irq_flags);

		if (rc)

			goto err_no_dma;

	}

	}



	dev_dbg(&pdev->dev, "Initialized %i DMA channels\n", i);

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