From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
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: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
---
drivers/dma/bcm2835-dma.c | 77 ++++++++++++++++++++++++++++++++++++++---------
1 file changed, 63 insertions(+), 14 deletions(-)
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index cc771cd..9740151 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -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;
@@ -941,16 +958,48 @@ 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)
- break;
-
- if (chans_available & (1 << i)) {
- rc = bcm2835_dma_chan_init(od, i, irq);
- if (rc)
- goto err_no_dma;
+ /* 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;
+ }
+
+ /* 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);
--
2.1.4
--
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