target/linux/brcm2708/patches-4.4/0400-dmaengine-bcm2835-use-platform_get_irq_byname.patch

   1 From 27a895c19212e695f70bd4860d4420f70f915fe1 Mon Sep 17 00:00:00 2001
   2 From: Martin Sperl <kernel@martin.sperl.org>
   3 Date: Mon, 11 Apr 2016 13:29:08 +0000
   4 Subject: [PATCH] dmaengine: bcm2835: use platform_get_irq_byname
   5
   6 Use platform_get_irq_byname to allow for correct mapping of
   7 interrupts to dma channels.
   8
   9 The currently implemented device tree is unfortunately
  10 implemented with the wrong assumption, that each dma-channel
  11 has its own dma channel, but dma-irq 11 is handling
  12 dma-channel 11-14 and dma-irq 12 is actually a "catch all"
  13 interrupt.
  14
  15 So here we use the byname variant and require that interrupts
  16 are explicitly named via the interrupts-name property in the
  17 device tree.
  18
  19 The use of shared interrupts is also implemented.
  20
  21 As a side-effect this means we can now use dma channels 12, 13 and 14
  22 in a correct manner - also testing shows that onl using
  23 channels 11 to 14 for spi and i2s works perfectly (when playing
  24 some video)
  25
  26 Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
  27 Acked-by: Eric Anholt <eric@anholt.net>
  28 Acked-by: Mark Rutland <mark.rutland@arm.com>
  29 Signed-off-by: Vinod Koul <vinod.koul@intel.com>
  30 ---
  31  drivers/dma/bcm2835-dma.c | 77 ++++++++++++++++++++++++++++++++++++++---------
  32  1 file changed, 63 insertions(+), 14 deletions(-)
  33
  34 --- a/drivers/dma/bcm2835-dma.c
  35 +++ b/drivers/dma/bcm2835-dma.c
  36 @@ -46,6 +46,9 @@
  37
  38  #include "virt-dma.h"
  39
  40 +#define BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED 14
  41 +#define BCM2835_DMA_CHAN_NAME_SIZE 8
  42 +
  43  struct bcm2835_dmadev {
  44         struct dma_device ddev;
  45         spinlock_t lock;
  46 @@ -81,6 +84,7 @@ struct bcm2835_chan {
  47
  48         void __iomem *chan_base;
  49         int irq_number;
  50 +       unsigned int irq_flags;
  51
  52         bool is_lite_channel;
  53  };
  54 @@ -466,6 +470,15 @@ static irqreturn_t bcm2835_dma_callback(
  55         struct bcm2835_desc *d;
  56         unsigned long flags;
  57
  58 +       /* check the shared interrupt */
  59 +       if (c->irq_flags & IRQF_SHARED) {
  60 +               /* check if the interrupt is enabled */
  61 +               flags = readl(c->chan_base + BCM2835_DMA_CS);
  62 +               /* if not set then we are not the reason for the irq */
  63 +               if (!(flags & BCM2835_DMA_INT))
  64 +                       return IRQ_NONE;
  65 +       }
  66 +
  67         spin_lock_irqsave(&c->vc.lock, flags);
  68
  69         /* Acknowledge interrupt */
  70 @@ -506,8 +519,8 @@ static int bcm2835_dma_alloc_chan_resour
  71                 return -ENOMEM;
  72         }
  73
  74 -       return request_irq(c->irq_number,
  75 -                       bcm2835_dma_callback, 0, "DMA IRQ", c);
  76 +       return request_irq(c->irq_number, bcm2835_dma_callback,
  77 +                          c->irq_flags, "DMA IRQ", c);
  78  }
  79
  80  static void bcm2835_dma_free_chan_resources(struct dma_chan *chan)
  81 @@ -819,7 +832,8 @@ static int bcm2835_dma_terminate_all(str
  82         return 0;
  83  }
  84
  85 -static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id, int irq)
  86 +static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id,
  87 +                                int irq, unsigned int irq_flags)
  88  {
  89         struct bcm2835_chan *c;
  90
  91 @@ -834,6 +848,7 @@ static int bcm2835_dma_chan_init(struct
  92         c->chan_base = BCM2835_DMA_CHANIO(d->base, chan_id);
  93         c->ch = chan_id;
  94         c->irq_number = irq;
  95 +       c->irq_flags = irq_flags;
  96
  97         /* check in DEBUG register if this is a LITE channel */
  98         if (readl(c->chan_base + BCM2835_DMA_DEBUG) &
  99 @@ -882,9 +897,11 @@ static int bcm2835_dma_probe(struct plat
 100         struct resource *res;
 101         void __iomem *base;
 102         int rc;
 103 -       int i;
 104 -       int irq;
 105 +       int i, j;
 106 +       int irq[BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED + 1];
 107 +       int irq_flags;
 108         uint32_t chans_available;
 109 +       char chan_name[BCM2835_DMA_CHAN_NAME_SIZE];
 110
 111         if (!pdev->dev.dma_mask)
 112                 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
 113 @@ -941,16 +958,48 @@ static int bcm2835_dma_probe(struct plat
 114                 goto err_no_dma;
 115         }
 116
 117 -       for (i = 0; i < pdev->num_resources; i++) {
 118 -               irq = platform_get_irq(pdev, i);
 119 -               if (irq < 0)
 120 -                       break;
 121 -
 122 -               if (chans_available & (1 << i)) {
 123 -                       rc = bcm2835_dma_chan_init(od, i, irq);
 124 -                       if (rc)
 125 -                               goto err_no_dma;
 126 +       /* get irqs for each channel that we support */
 127 +       for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) {
 128 +               /* skip masked out channels */
 129 +               if (!(chans_available & (1 << i))) {
 130 +                       irq[i] = -1;
 131 +                       continue;
 132                 }
 133 +
 134 +               /* get the named irq */
 135 +               snprintf(chan_name, sizeof(chan_name), "dma%i", i);
 136 +               irq[i] = platform_get_irq_byname(pdev, chan_name);
 137 +               if (irq[i] >= 0)
 138 +                       continue;
 139 +
 140 +               /* legacy device tree case handling */
 141 +               dev_warn_once(&pdev->dev,
 142 +                             "missing interrupts-names property in device tree - legacy interpretation is used");
 143 +               /*
 144 +                * in case of channel >= 11
 145 +                * use the 11th interrupt and that is shared
 146 +                */
 147 +               irq[i] = platform_get_irq(pdev, i < 11 ? i : 11);
 148 +       }
 149 +
 150 +       /* get irqs for each channel */
 151 +       for (i = 0; i <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; i++) {
 152 +               /* skip channels without irq */
 153 +               if (irq[i] < 0)
 154 +                       continue;
 155 +
 156 +               /* check if there are other channels that also use this irq */
 157 +               irq_flags = 0;
 158 +               for (j = 0; j <= BCM2835_DMA_MAX_DMA_CHAN_SUPPORTED; j++)
 159 +                       if ((i != j) && (irq[j] == irq[i])) {
 160 +                               irq_flags = IRQF_SHARED;
 161 +                               break;
 162 +                       }
 163 +
 164 +               /* initialize the channel */
 165 +               rc = bcm2835_dma_chan_init(od, i, irq[i], irq_flags);
 166 +               if (rc)
 167 +                       goto err_no_dma;
 168         }
 169
 170         dev_dbg(&pdev->dev, "Initialized %i DMA channels\n", i);