linux-kernel - [PATCH 10/12] dmaengine: bcm2835: Support DMA-Lite channels

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Date: Sun,  4 Feb 2024 07:59:38 +0100
From: Andrea della Porta <andrea.porta@...e.com>
To: Vinod Koul <vkoul@...nel.org>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	Ray Jui <rjui@...adcom.com>,
	Scott Branden <sbranden@...adcom.com>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>,
	dmaengine@...r.kernel.org,
	linux-rpi-kernel@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Cc: Maxime Ripard <maxime@...no.tech>,
	Dom Cobley <popcornmix@...il.com>,
	Phil Elwell <phil@...pberrypi.com>,
	Andrea della Porta <andrea.porta@...e.com>
Subject: [PATCH 10/12] dmaengine: bcm2835: Support DMA-Lite channels

From: Maxime Ripard <maxime@...no.tech>

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.

Cc: Maxime Ripard <maxime@...no.tech>
Cc: Dom Cobley <popcornmix@...il.com>
Signed-off-by: Andrea della Porta <andrea.porta@...e.com>
---
 drivers/dma/bcm2835-dma.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index 548cf7343d83..055c558caa0e 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -100,6 +100,7 @@ struct bcm2835_chan {
 
 	bool is_lite_channel;
 	bool is_40bit_channel;
+	bool is_2712;
 };
 
 struct bcm2835_desc {
@@ -545,7 +546,11 @@ static struct bcm2835_desc *bcm2835_dma_create_cb_chain(
 			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;
 		}
 
@@ -570,7 +575,8 @@ static struct bcm2835_desc *bcm2835_dma_create_cb_chain(
 			 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)) {
@@ -750,7 +756,10 @@ static void bcm2835_dma_start_desc(struct bcm2835_chan *c)
 		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);
 	}
@@ -1119,7 +1128,8 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic(
 		 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);
 }
@@ -1186,6 +1196,8 @@ static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id,
 	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;
 }
-- 
2.41.0