git.openwrt.org Git - openwrt/staging/xback.git/blob

   1 From 132f5d41c2da9f7292f1495fd30cf04a3de8d196 Mon Sep 17 00:00:00 2001
   2 From: Dom Cobley <popcornmix@gmail.com>
   3 Date: Fri, 5 May 2023 11:23:50 +0100
   4 Subject: [PATCH] bcm2835-dma: Need to keep PROT bits set in CS on
   5  40bit controller
   6
   7 Resetting them to zero puts DMA channel into secure mode
   8 which makes further accesses impossible
   9
  10 Signed-off-by: Dom Cobley <popcornmix@gmail.com>
  11 ---
  12  drivers/dma/bcm2835-dma.c | 20 ++++++++++++++------
  13  1 file changed, 14 insertions(+), 6 deletions(-)
  14
  15 --- a/drivers/dma/bcm2835-dma.c
  16 +++ b/drivers/dma/bcm2835-dma.c
  17 @@ -249,6 +249,9 @@ struct bcm2835_desc {
  18  #define BCM2711_DMA40_DISDEBUG         BIT(29)
  19  #define BCM2711_DMA40_ABORT            BIT(30)
  20  #define BCM2711_DMA40_HALT             BIT(31)
  21 +// we always want to run in supervisor mode
  22 +#define BCM2711_DMA40_PROT             (BIT(8)|BIT(9))
  23 +
  24  #define BCM2711_DMA40_CS_FLAGS(x) (x & (BCM2711_DMA40_QOS(15) | \
  25                                         BCM2711_DMA40_PANIC_QOS(15) | \
  26                                         BCM2711_DMA40_WAIT_FOR_WRITES | \
  27 @@ -682,7 +685,7 @@ static void bcm2835_dma_abort(struct bcm
  28                         dev_err(c->vc.chan.device->dev,
  29                                 "failed to halt dma\n");
  30
  31 -               writel(0, chan_base + BCM2711_DMA40_CS);
  32 +               writel(BCM2711_DMA40_PROT, chan_base + BCM2711_DMA40_CS);
  33                 writel(0, chan_base + BCM2711_DMA40_CB);
  34         } else {
  35                 /*
  36 @@ -742,7 +745,7 @@ static void bcm2835_dma_start_desc(struc
  37         if (c->is_40bit_channel) {
  38                 writel(to_bcm2711_cbaddr(d->cb_list[0].paddr),
  39                        c->chan_base + BCM2711_DMA40_CB);
  40 -               writel(BCM2711_DMA40_ACTIVE | BCM2711_DMA40_CS_FLAGS(c->dreq),
  41 +               writel(BCM2711_DMA40_ACTIVE | BCM2711_DMA40_PROT | BCM2711_DMA40_CS_FLAGS(c->dreq),
  42                        c->chan_base + BCM2711_DMA40_CS);
  43         } else {
  44                 writel(d->cb_list[0].paddr, c->chan_base + BCM2835_DMA_ADDR);
  45 @@ -775,8 +778,13 @@ static irqreturn_t bcm2835_dma_callback(
  46          * if this IRQ handler is threaded.) If the channel is finished, it
  47          * will remain idle despite the ACTIVE flag being set.
  48          */
  49 -       writel(BCM2835_DMA_INT | BCM2835_DMA_ACTIVE | BCM2835_DMA_CS_FLAGS(c->dreq),
  50 -              c->chan_base + BCM2835_DMA_CS);
  51 +       if (c->is_40bit_channel)
  52 +               writel(BCM2835_DMA_INT | BCM2711_DMA40_ACTIVE | BCM2711_DMA40_PROT |
  53 +                      BCM2711_DMA40_CS_FLAGS(c->dreq),
  54 +                      c->chan_base + BCM2711_DMA40_CS);
  55 +       else
  56 +               writel(BCM2835_DMA_INT | BCM2835_DMA_ACTIVE | BCM2835_DMA_CS_FLAGS(c->dreq),
  57 +                      c->chan_base + BCM2835_DMA_CS);
  58
  59         d = c->desc;
  60
  61 @@ -1230,14 +1238,14 @@ void bcm2711_dma40_memcpy(dma_addr_t dst
  62         scb->next_cb = 0;
  63
  64         writel(to_bcm2711_cbaddr(memcpy_scb_dma), memcpy_chan + BCM2711_DMA40_CB);
  65 -       writel(BCM2711_DMA40_MEMCPY_FLAGS + BCM2711_DMA40_ACTIVE,
  66 +       writel(BCM2711_DMA40_MEMCPY_FLAGS | BCM2711_DMA40_ACTIVE | BCM2711_DMA40_PROT,
  67                memcpy_chan + BCM2711_DMA40_CS);
  68
  69         /* Poll for completion */
  70         while (!(readl(memcpy_chan + BCM2711_DMA40_CS) & BCM2711_DMA40_END))
  71                 cpu_relax();
  72
  73 -       writel(BCM2711_DMA40_END, memcpy_chan + BCM2711_DMA40_CS);
  74 +       writel(BCM2711_DMA40_END | BCM2711_DMA40_PROT, memcpy_chan + BCM2711_DMA40_CS);
  75
  76         spin_unlock_irqrestore(&memcpy_lock, flags);
  77  }