171 lines
4.9 KiB
Diff
171 lines
4.9 KiB
Diff
From 2913407433c67a96d02bc4b4c1e5111fdb6d356d Mon Sep 17 00:00:00 2001
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From: Martin Sperl <kernel@martin.sperl.org>
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Date: Mon, 11 Apr 2016 13:29:08 +0000
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Subject: [PATCH] dmaengine: bcm2835: use platform_get_irq_byname
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Use platform_get_irq_byname to allow for correct mapping of
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interrupts to dma channels.
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The currently implemented device tree is unfortunately
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implemented with the wrong assumption, that each dma-channel
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has its own dma channel, but dma-irq 11 is handling
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dma-channel 11-14 and dma-irq 12 is actually a "catch all"
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interrupt.
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So here we use the byname variant and require that interrupts
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are explicitly named via the interrupts-name property in the
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device tree.
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The use of shared interrupts is also implemented.
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As a side-effect this means we can now use dma channels 12, 13 and 14
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in a correct manner - also testing shows that onl using
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channels 11 to 14 for spi and i2s works perfectly (when playing
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some video)
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Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
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Acked-by: Eric Anholt <eric@anholt.net>
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Acked-by: Mark Rutland <mark.rutland@arm.com>
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Signed-off-by: Vinod Koul <vinod.koul@intel.com>
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---
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drivers/dma/bcm2835-dma.c | 77 ++++++++++++++++++++++++++++++++++++++---------
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1 file changed, 63 insertions(+), 14 deletions(-)
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--- a/drivers/dma/bcm2835-dma.c
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+++ b/drivers/dma/bcm2835-dma.c
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@@ -46,6 +46,9 @@
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#include "virt-dma.h"
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+#define BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED 14
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+#define BCM2835_DMA_CHAN_NAME_SIZE 8
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+
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struct bcm2835_dmadev {
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struct dma_device ddev;
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spinlock_t lock;
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@@ -81,6 +84,7 @@ struct bcm2835_chan {
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void __iomem *chan_base;
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int irq_number;
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+ unsigned int irq_flags;
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bool is_lite_channel;
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};
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@@ -466,6 +470,15 @@ static irqreturn_t bcm2835_dma_callback(
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struct bcm2835_desc *d;
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unsigned long flags;
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+ /* check the shared interrupt */
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+ if (c->irq_flags & IRQF_SHARED) {
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+ /* check if the interrupt is enabled */
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+ flags = readl(c->chan_base + BCM2835_DMA_CS);
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+ /* if not set then we are not the reason for the irq */
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+ if (!(flags & BCM2835_DMA_INT))
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+ return IRQ_NONE;
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+ }
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+
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spin_lock_irqsave(&c->vc.lock, flags);
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/* Acknowledge interrupt */
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@@ -506,8 +519,8 @@ static int bcm2835_dma_alloc_chan_resour
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return -ENOMEM;
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}
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- return request_irq(c->irq_number,
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- bcm2835_dma_callback, 0, "DMA IRQ", c);
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+ return request_irq(c->irq_number, bcm2835_dma_callback,
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+ c->irq_flags, "DMA IRQ", c);
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}
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static void bcm2835_dma_free_chan_resources(struct dma_chan *chan)
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@@ -819,7 +832,8 @@ static int bcm2835_dma_terminate_all(str
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return 0;
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}
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-static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id, int irq)
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+static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id,
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+ int irq, unsigned int irq_flags)
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{
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struct bcm2835_chan *c;
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@@ -834,6 +848,7 @@ static int bcm2835_dma_chan_init(struct
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c->chan_base = BCM2835_DMA_CHANIO(d->base, chan_id);
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c->ch = chan_id;
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c->irq_number = irq;
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+ c->irq_flags = irq_flags;
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/* check in DEBUG register if this is a LITE channel */
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if (readl(c->chan_base + BCM2835_DMA_DEBUG) &
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@@ -882,9 +897,11 @@ static int bcm2835_dma_probe(struct plat
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struct resource *res;
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void __iomem *base;
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int rc;
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- int i;
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- int irq;
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+ int i, j;
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+ int irq[BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED + 1];
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+ int irq_flags;
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uint32_t chans_available;
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+ char chan_name[BCM2835_DMA_CHAN_NAME_SIZE];
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if (!pdev->dev.dma_mask)
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pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
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@@ -941,16 +958,48 @@ static int bcm2835_dma_probe(struct plat
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goto err_no_dma;
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}
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- for (i = 0; i < pdev->num_resources; i++) {
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- irq = platform_get_irq(pdev, i);
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- if (irq < 0)
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- break;
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-
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- if (chans_available & (1 << i)) {
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- rc = bcm2835_dma_chan_init(od, i, irq);
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- if (rc)
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- goto err_no_dma;
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+ /* get irqs for each channel that we support */
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+ for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) {
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+ /* skip masked out channels */
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+ if (!(chans_available & (1 << i))) {
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+ irq[i] = -1;
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+ continue;
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}
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+
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+ /* get the named irq */
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+ snprintf(chan_name, sizeof(chan_name), "dma%i", i);
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+ irq[i] = platform_get_irq_byname(pdev, chan_name);
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+ if (irq[i] >= 0)
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+ continue;
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+
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+ /* legacy device tree case handling */
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+ dev_warn_once(&pdev->dev,
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+ "missing interrupts-names property in device tree - legacy interpretation is used");
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+ /*
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+ * in case of channel >= 11
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+ * use the 11th interrupt and that is shared
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+ */
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+ irq[i] = platform_get_irq(pdev, i < 11 ? i : 11);
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+ }
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+
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+ /* get irqs for each channel */
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+ for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) {
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+ /* skip channels without irq */
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+ if (irq[i] < 0)
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+ continue;
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+
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+ /* check if there are other channels that also use this irq */
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+ irq_flags = 0;
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+ for (j = 0; j <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; j++)
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+ if ((i != j) && (irq[j] == irq[i])) {
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+ irq_flags = IRQF_SHARED;
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+ break;
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+ }
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+
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+ /* initialize the channel */
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+ rc = bcm2835_dma_chan_init(od, i, irq[i], irq_flags);
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+ if (rc)
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+ goto err_no_dma;
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}
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dev_dbg(&pdev->dev, "Initialized %i DMA channels\n", i);
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