target/linux/brcm2708/patches-4.19/950-0338-bcm2835-dma-Add-support-for-per-channel-flags.patch

   1 From f1eb781eb15506a49307cd80ad5b70533622ee68 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Fri, 20 Jul 2018 22:03:41 +0100
   4 Subject: [PATCH 338/703] bcm2835-dma: Add support for per-channel flags
   5
   6 Add the ability to interpret the high bits of the dreq specifier as
   7 flags to be included in the DMA_CS register. The motivation for this
   8 change is the ability to set the DISDEBUG flag for SD card transfers
   9 to avoid corruption when using the VPU debugger.
  10
  11 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
  12 ---
  13  drivers/dma/bcm2835-dma.c | 10 ++++++++--
  14  1 file changed, 8 insertions(+), 2 deletions(-)
  15
  16 --- a/drivers/dma/bcm2835-dma.c
  17 +++ b/drivers/dma/bcm2835-dma.c
  18 @@ -146,6 +146,10 @@ struct bcm2835_desc {
  19  #define BCM2835_DMA_S_DREQ     BIT(10) /* enable SREQ for source */
  20  #define BCM2835_DMA_S_IGNORE   BIT(11) /* ignore source reads - read 0 */
  21  #define BCM2835_DMA_BURST_LENGTH(x) ((x & 15) << 12)
  22 +#define BCM2835_DMA_CS_FLAGS(x) (x & (BCM2835_DMA_PRIORITY(15) | \
  23 +                                     BCM2835_DMA_PANIC_PRIORITY(15) | \
  24 +                                     BCM2835_DMA_WAIT_FOR_WRITES | \
  25 +                                     BCM2835_DMA_DIS_DEBUG))
  26  #define BCM2835_DMA_PER_MAP(x) ((x & 31) << 16) /* REQ source */
  27  #define BCM2835_DMA_WAIT(x)    ((x & 31) << 21) /* add DMA-wait cycles */
  28  #define BCM2835_DMA_NO_WIDE_BURSTS BIT(26) /* no 2 beat write bursts */
  29 @@ -461,7 +465,8 @@ static void bcm2835_dma_start_desc(struc
  30         c->desc = d = to_bcm2835_dma_desc(&vd->tx);
  31
  32         writel(d->cb_list[0].paddr, c->chan_base + BCM2835_DMA_ADDR);
  33 -       writel(BCM2835_DMA_ACTIVE, c->chan_base + BCM2835_DMA_CS);
  34 +       writel(BCM2835_DMA_ACTIVE | BCM2835_DMA_CS_FLAGS(c->dreq),
  35 +              c->chan_base + BCM2835_DMA_CS);
  36  }
  37
  38  static irqreturn_t bcm2835_dma_callback(int irq, void *data)
  39 @@ -488,7 +493,8 @@ static irqreturn_t bcm2835_dma_callback(
  40          * if this IRQ handler is threaded.) If the channel is finished, it
  41          * will remain idle despite the ACTIVE flag being set.
  42          */
  43 -       writel(BCM2835_DMA_INT | BCM2835_DMA_ACTIVE,
  44 +       writel(BCM2835_DMA_INT | BCM2835_DMA_ACTIVE |
  45 +              BCM2835_DMA_CS_FLAGS(c->dreq),
  46                c->chan_base + BCM2835_DMA_CS);
  47
  48         d = c->desc;