target/linux/brcm2708/patches-4.4/0401-dmaengine-bcm2835-Load-driver-early-and-support-lega.patch

   1 From 479b918cb9511d5044cc660f0c74d42952a87910 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
   3 Date: Sat, 3 Oct 2015 22:22:55 +0200
   4 Subject: [PATCH] dmaengine: bcm2835: Load driver early and support legacy API
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Load driver early since at least bcm2708_fb doesn't support deferred
  10 probing and even if it did, we don't want the video driver deferred.
  11
  12 Support the legacy DMA API which is needed by bcm2708_fb
  13 (but only using the dedicated dma channel 0).
  14
  15 Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
  16 Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
  17 ---
  18  drivers/dma/Kconfig       |  2 +-
  19  drivers/dma/bcm2835-dma.c | 27 ++++++++++++++++++++++++++-
  20  2 files changed, 27 insertions(+), 2 deletions(-)
  21
  22 --- a/drivers/dma/Kconfig
  23 +++ b/drivers/dma/Kconfig
  24 @@ -108,7 +108,7 @@ config COH901318
  25
  26  config DMA_BCM2835
  27         tristate "BCM2835 DMA engine support"
  28 -       depends on ARCH_BCM2835
  29 +       depends on ARCH_BCM2835 || ARCH_BCM2708 || ARCH_BCM2709
  30         select DMA_ENGINE
  31         select DMA_VIRTUAL_CHANNELS
  32
  33 --- a/drivers/dma/bcm2835-dma.c
  34 +++ b/drivers/dma/bcm2835-dma.c
  35 @@ -37,6 +37,7 @@
  36  #include <linux/interrupt.h>
  37  #include <linux/list.h>
  38  #include <linux/module.h>
  39 +#include <linux/platform_data/dma-bcm2708.h>
  40  #include <linux/platform_device.h>
  41  #include <linux/slab.h>
  42  #include <linux/io.h>
  43 @@ -1021,6 +1022,14 @@ static int bcm2835_dma_probe(struct plat
  44
  45         dev_dbg(&pdev->dev, "Load BCM2835 DMA engine driver\n");
  46
  47 +       /* load the legacy api if bit 0 in the mask is cleared */
  48 +       if ((chans_available & BIT(0)) == 0) {
  49 +               rc = bcm_dmaman_probe(pdev, base, BIT(0));
  50 +               if (rc)
  51 +                       dev_err(&pdev->dev,
  52 +                               "Failed to initialize the legacy API\n");
  53 +       }
  54 +
  55         return 0;
  56
  57  err_no_dma:
  58 @@ -1032,6 +1041,7 @@ static int bcm2835_dma_remove(struct pla
  59  {
  60         struct bcm2835_dmadev *od = platform_get_drvdata(pdev);
  61
  62 +       bcm_dmaman_remove(pdev);
  63         dma_async_device_unregister(&od->ddev);
  64         bcm2835_dma_free(od);
  65
  66 @@ -1047,7 +1057,22 @@ static struct platform_driver bcm2835_dm
  67         },
  68  };
  69
  70 -module_platform_driver(bcm2835_dma_driver);
  71 +static int bcm2835_dma_init(void)
  72 +{
  73 +       return platform_driver_register(&bcm2835_dma_driver);
  74 +}
  75 +
  76 +static void bcm2835_dma_exit(void)
  77 +{
  78 +       platform_driver_unregister(&bcm2835_dma_driver);
  79 +}
  80 +
  81 +/*
  82 + * Load after serial driver (arch_initcall) so we see the messages if it fails,
  83 + * but before drivers (module_init) that need a DMA channel.
  84 + */
  85 +subsys_initcall(bcm2835_dma_init);
  86 +module_exit(bcm2835_dma_exit);
  87
  88  MODULE_ALIAS("platform:bcm2835-dma");
  89  MODULE_DESCRIPTION("BCM2835 DMA engine driver");