From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> The bcm2835 dma channel 11 to 14 only have a single shared irq line, so this patch implements shared interrupts for these channels. This patch also introduces 2 new device-tree properties (optional for compatibility with older device-trees): * brcm,dma-channel-shared-mask - default: 0x0780 * brcm,dma-shared-irq-index - default: 11 With this patch applied we now have 11 dma channels available to the ARM side of the SOC. Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> Reviewed-by: Eric Anholt <eric@xxxxxxxxxx> --- drivers/dma/bcm2835-dma.c | 64 ++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 58 insertions(+), 6 deletions(-) diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c index e4ca980..fe7d5a6 100644 --- a/drivers/dma/bcm2835-dma.c +++ b/drivers/dma/bcm2835-dma.c @@ -81,7 +81,9 @@ struct bcm2835_chan { struct dma_pool *cb_pool; void __iomem *chan_base; + int irq_number; + unsigned long irq_flags; }; struct bcm2835_desc { @@ -127,6 +129,20 @@ struct bcm2835_desc { #define BCM2835_DMA_CHAN(n) ((n) << 8) /* Base address */ #define BCM2835_DMA_CHANIO(base, n) ((base) + BCM2835_DMA_CHAN(n)) +/* + * number of dma channels we support + * we do not support DMA channel 15, as it is in a separate IO range, + * does not have a separate IRQ line except for the "catch all IRQ line" + * finally this channel is used by the firmware so is not available + */ +#define BCM2835_DMA_MAX_CHANNEL_NUMBER 14 + +/* the DMA channels 11 to 14 share a common interrupt */ +#define BCM2835_DMA_IRQ_SHARED_MASK_DEFAULT \ + (BIT(11) | BIT(12) | BIT(13) | BIT(14)) +#define BCM2835_DMA_IRQ_SHARED_DEFAULT 11 +#define BCM2835_DMA_IRQ_ALL_DEFAULT 12 + static inline struct bcm2835_dmadev *to_bcm2835_dma_dev(struct dma_device *d) { return container_of(d, struct bcm2835_dmadev, ddev); @@ -215,6 +231,15 @@ 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 */ @@ -250,7 +275,8 @@ static int bcm2835_dma_alloc_chan_resources(struct dma_chan *chan) } return request_irq(c->irq_number, - bcm2835_dma_callback, 0, "DMA IRQ", c); + bcm2835_dma_callback, + c->irq_flags, "DMA IRQ", c); } static void bcm2835_dma_free_chan_resources(struct dma_chan *chan) @@ -526,7 +552,8 @@ 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 long irq_flags) { struct bcm2835_chan *c; @@ -541,6 +568,7 @@ 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; return 0; } @@ -586,7 +614,8 @@ static int bcm2835_dma_probe(struct platform_device *pdev) int rc; int i; int irq; - uint32_t chans_available; + unsigned long irq_flags; + u32 chans_available, chans_shared_irq_mask, shared_irq_index; if (!pdev->dev.dma_mask) pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; @@ -637,14 +666,37 @@ static int bcm2835_dma_probe(struct platform_device *pdev) rc = -EINVAL; goto err_no_dma; } + /* we do not support more channels */ + chans_available &= BIT(BCM2835_DMA_MAX_CHANNEL_NUMBER + 1) - 1; + + /* get shared irq mask falling back to defaults */ + chans_shared_irq_mask = BCM2835_DMA_IRQ_SHARED_MASK_DEFAULT; + of_property_read_u32(pdev->dev.of_node, + "brcm,dma-channel-shared-mask", + &chans_shared_irq_mask); + + /* get shared irq index falling back to default */ + shared_irq_index = BCM2835_DMA_IRQ_SHARED_DEFAULT; + of_property_read_u32(pdev->dev.of_node, + "brcm,dma-shared-irq-index", + &shared_irq_index); + + /* loop over all channels */ + for (i = 0; i <= fls(chans_available); i++) { + if (chans_shared_irq_mask & BIT(i)) { + irq = platform_get_irq(pdev, + shared_irq_index); + irq_flags = IRQF_SHARED; + } else { + irq = platform_get_irq(pdev, i); + irq_flags = 0; + } - 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); + rc = bcm2835_dma_chan_init(od, i, irq, irq_flags); if (rc) goto err_no_dma; } -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html