From 7584f8047c47c821bb0cf2ea21b53a9e92e5a52b Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Thu, 13 Apr 2023 16:52:19 +0200
Subject: [PATCH] dmaengine: bcm2835: HACK: Support DMA-Lite channels

The BCM2712 has a DMA-Lite controller that is basically a BCM2835-style
DMA controller that supports 40 bits DMA addresses.

We need it for HDMI audio to work, but this breaks BCM2835-38 so we
should rework this later.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

dmaengine: bcm2835: Fix dma driver for BCM2835-38

The previous commit broke support on older devices.
Make the breaking parts of patch conditional on
the device being used.

Fixes: 6e1856ac7c39 ("dmaengine: bcm2835: HACK: Support DMA-Lite channels")

Signed-off-by: Dom Cobley <popcornmix@gmail.com>
---
 drivers/dma/bcm2835-dma.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -101,6 +101,7 @@ struct bcm2835_chan {
 
 	bool is_lite_channel;
 	bool is_40bit_channel;
+	bool is_2712;
 };
 
 struct bcm2835_desc {
@@ -549,7 +550,11 @@ static struct bcm2835_desc *bcm2835_dma_
 			control_block->info = info;
 			control_block->src = src;
 			control_block->dst = dst;
-			control_block->stride = 0;
+			if (c->is_2712)
+				control_block->stride = (upper_32_bits(dst) << 8) |
+							upper_32_bits(src);
+			else
+				control_block->stride = 0;
 			control_block->next = 0;
 		}
 
@@ -574,7 +579,8 @@ static struct bcm2835_desc *bcm2835_dma_
 			 d->cb_list[frame - 1].cb)->next_cb =
 				to_bcm2711_cbaddr(cb_entry->paddr);
 		if (frame && !c->is_40bit_channel)
-			d->cb_list[frame - 1].cb->next = cb_entry->paddr;
+			d->cb_list[frame - 1].cb->next = c->is_2712 ?
+			to_bcm2711_cbaddr(cb_entry->paddr) : cb_entry->paddr;
 
 		/* update src and dst and length */
 		if (src && (info & BCM2835_DMA_S_INC)) {
@@ -759,7 +765,10 @@ static void bcm2835_dma_start_desc(struc
 		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);
+		writel(BIT(31), c->chan_base + BCM2835_DMA_CS);
+
+		writel(c->is_2712 ? to_bcm2711_cbaddr(d->cb_list[0].paddr) : d->cb_list[0].paddr,
+		       c->chan_base + BCM2835_DMA_ADDR);
 		writel(BCM2835_DMA_ACTIVE | BCM2835_DMA_CS_FLAGS(c->dreq),
 		       c->chan_base + BCM2835_DMA_CS);
 	}
@@ -1132,7 +1141,8 @@ static struct dma_async_tx_descriptor *b
 		 d->cb_list[frames - 1].cb)->next_cb =
 			to_bcm2711_cbaddr(d->cb_list[0].paddr);
 	else
-		d->cb_list[d->frames - 1].cb->next = d->cb_list[0].paddr;
+		d->cb_list[d->frames - 1].cb->next = c->is_2712 ?
+		to_bcm2711_cbaddr(d->cb_list[0].paddr) : d->cb_list[0].paddr;
 
 	return vchan_tx_prep(&c->vc, &d->vd, flags);
 }
@@ -1199,6 +1209,8 @@ static int bcm2835_dma_chan_init(struct
 	else if (readl(c->chan_base + BCM2835_DMA_DEBUG) &
 		 BCM2835_DMA_DEBUG_LITE)
 		c->is_lite_channel = true;
+	if (d->cfg_data->dma_mask == DMA_BIT_MASK(40))
+		c->is_2712 = true;
 
 	return 0;
 }
