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From 132f5d41c2da9f7292f1495fd30cf04a3de8d196 Mon Sep 17 00:00:00 2001
From: Dom Cobley <popcornmix@gmail.com>
Date: Fri, 5 May 2023 11:23:50 +0100
Subject: [PATCH] bcm2835-dma: Need to keep PROT bits set in CS on
40bit controller
Resetting them to zero puts DMA channel into secure mode
which makes further accesses impossible
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
---
drivers/dma/bcm2835-dma.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -249,6 +249,9 @@ struct bcm2835_desc {
#define BCM2711_DMA40_DISDEBUG BIT(29)
#define BCM2711_DMA40_ABORT BIT(30)
#define BCM2711_DMA40_HALT BIT(31)
+// we always want to run in supervisor mode
+#define BCM2711_DMA40_PROT (BIT(8)|BIT(9))
+
#define BCM2711_DMA40_CS_FLAGS(x) (x & (BCM2711_DMA40_QOS(15) | \
BCM2711_DMA40_PANIC_QOS(15) | \
BCM2711_DMA40_WAIT_FOR_WRITES | \
@@ -682,7 +685,7 @@ static void bcm2835_dma_abort(struct bcm
dev_err(c->vc.chan.device->dev,
"failed to halt dma\n");
- writel(0, chan_base + BCM2711_DMA40_CS);
+ writel(BCM2711_DMA40_PROT, chan_base + BCM2711_DMA40_CS);
writel(0, chan_base + BCM2711_DMA40_CB);
} else {
/*
@@ -742,7 +745,7 @@ static void bcm2835_dma_start_desc(struc
if (c->is_40bit_channel) {
writel(to_bcm2711_cbaddr(d->cb_list[0].paddr),
c->chan_base + BCM2711_DMA40_CB);
- writel(BCM2711_DMA40_ACTIVE | BCM2711_DMA40_CS_FLAGS(c->dreq),
+ writel(BCM2711_DMA40_ACTIVE | BCM2711_DMA40_PROT | BCM2711_DMA40_CS_FLAGS(c->dreq),
c->chan_base + BCM2711_DMA40_CS);
} else {
writel(d->cb_list[0].paddr, c->chan_base + BCM2835_DMA_ADDR);
@@ -775,8 +778,13 @@ static irqreturn_t bcm2835_dma_callback(
* if this IRQ handler is threaded.) If the channel is finished, it
* will remain idle despite the ACTIVE flag being set.
*/
- writel(BCM2835_DMA_INT | BCM2835_DMA_ACTIVE | BCM2835_DMA_CS_FLAGS(c->dreq),
- c->chan_base + BCM2835_DMA_CS);
+ if (c->is_40bit_channel)
+ writel(BCM2835_DMA_INT | BCM2711_DMA40_ACTIVE | BCM2711_DMA40_PROT |
+ BCM2711_DMA40_CS_FLAGS(c->dreq),
+ c->chan_base + BCM2711_DMA40_CS);
+ else
+ writel(BCM2835_DMA_INT | BCM2835_DMA_ACTIVE | BCM2835_DMA_CS_FLAGS(c->dreq),
+ c->chan_base + BCM2835_DMA_CS);
d = c->desc;
@@ -1230,14 +1238,14 @@ void bcm2711_dma40_memcpy(dma_addr_t dst
scb->next_cb = 0;
writel(to_bcm2711_cbaddr(memcpy_scb_dma), memcpy_chan + BCM2711_DMA40_CB);
- writel(BCM2711_DMA40_MEMCPY_FLAGS + BCM2711_DMA40_ACTIVE,
+ writel(BCM2711_DMA40_MEMCPY_FLAGS | BCM2711_DMA40_ACTIVE | BCM2711_DMA40_PROT,
memcpy_chan + BCM2711_DMA40_CS);
/* Poll for completion */
while (!(readl(memcpy_chan + BCM2711_DMA40_CS) & BCM2711_DMA40_END))
cpu_relax();
- writel(BCM2711_DMA40_END, memcpy_chan + BCM2711_DMA40_CS);
+ writel(BCM2711_DMA40_END | BCM2711_DMA40_PROT, memcpy_chan + BCM2711_DMA40_CS);
spin_unlock_irqrestore(&memcpy_lock, flags);
}
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