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* [PATCH] tty: serial: fsl_lpuart: use dmaengine_get_dma_device() for DMA mapping
@ 2026-09-16 15:27 Peng Fan (OSS)
  2026-09-16 19:22 ` Frank Li
  0 siblings, 1 reply; 2+ messages in thread
From: Peng Fan (OSS) @ 2026-09-16 15:27 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Jiri Slaby, Frank Li
  Cc: Sherry Sun, imx, linux-kernel, linux-serial, Peng Fan

From: Peng Fan <peng.fan@nxp.com>

Replace all chan->device->dev references with
dmaengine_get_dma_device(chan) so that DMA mapping goes through the
correct device when the DMA controller has per-channel IOMMU domains
(chan_dma_dev=true). Without this, DMA map/unmap/sync bypasses the
IOMMU context configured by the eDMA driver.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/tty/serial/fsl_lpuart.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index b7919c05f0fb8..c8575c9652035 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -491,7 +491,7 @@ static void lpuart_dma_tx(struct lpuart_port *sport)
 	sport->dma_tx_nents = kfifo_dma_out_prepare(&tport->xmit_fifo, sgl,
 			ARRAY_SIZE(sport->tx_sgl), sport->dma_tx_bytes);
 
-	ret = dma_map_sg(chan->device->dev, sgl, sport->dma_tx_nents,
+	ret = dma_map_sg(dmaengine_get_dma_device(chan), sgl, sport->dma_tx_nents,
 			 DMA_TO_DEVICE);
 	if (!ret) {
 		dev_err(dev, "DMA mapping error for TX.\n");
@@ -502,7 +502,7 @@ static void lpuart_dma_tx(struct lpuart_port *sport)
 					ret, DMA_MEM_TO_DEV,
 					DMA_PREP_INTERRUPT);
 	if (!sport->dma_tx_desc) {
-		dma_unmap_sg(chan->device->dev, sgl, sport->dma_tx_nents,
+		dma_unmap_sg(dmaengine_get_dma_device(chan), sgl, sport->dma_tx_nents,
 			      DMA_TO_DEVICE);
 		dev_err(dev, "Cannot prepare TX slave DMA!\n");
 		return;
@@ -535,7 +535,7 @@ static void lpuart_dma_tx_complete(void *arg)
 		return;
 	}
 
-	dma_unmap_sg(chan->device->dev, sgl, sport->dma_tx_nents,
+	dma_unmap_sg(dmaengine_get_dma_device(chan), sgl, sport->dma_tx_nents,
 		     DMA_TO_DEVICE);
 
 	uart_xmit_advance(&sport->port, sport->dma_tx_bytes);
@@ -606,7 +606,7 @@ static void lpuart_flush_buffer(struct uart_port *port)
 
 	if (sport->lpuart_dma_tx_use) {
 		if (sport->dma_tx_in_progress) {
-			dma_unmap_sg(chan->device->dev, &sport->tx_sgl[0],
+			dma_unmap_sg(dmaengine_get_dma_device(chan), &sport->tx_sgl[0],
 				sport->dma_tx_nents, DMA_TO_DEVICE);
 			sport->dma_tx_in_progress = false;
 		}
@@ -1176,7 +1176,7 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
 	}
 
 	/* CPU claims ownership of RX DMA buffer */
-	dma_sync_sg_for_cpu(chan->device->dev, &sport->rx_sgl, 1,
+	dma_sync_sg_for_cpu(dmaengine_get_dma_device(chan), &sport->rx_sgl, 1,
 			    DMA_FROM_DEVICE);
 
 	/*
@@ -1237,7 +1237,7 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
 	sport->last_residue = state.residue;
 
 exit:
-	dma_sync_sg_for_device(chan->device->dev, &sport->rx_sgl, 1,
+	dma_sync_sg_for_device(dmaengine_get_dma_device(chan), &sport->rx_sgl, 1,
 			       DMA_FROM_DEVICE);
 
 	uart_port_unlock_irqrestore(&sport->port, flags);
@@ -1374,7 +1374,7 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
 		return -ENOMEM;
 
 	sg_init_one(&sport->rx_sgl, ring->buf, sport->rx_dma_rng_buf_len);
-	nent = dma_map_sg(chan->device->dev, &sport->rx_sgl, 1,
+	nent = dma_map_sg(dmaengine_get_dma_device(chan), &sport->rx_sgl, 1,
 			  DMA_FROM_DEVICE);
 
 	if (!nent) {
@@ -1430,7 +1430,7 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
 	return 0;
 
 err_unmap_sg:
-	dma_unmap_sg(chan->device->dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
+	dma_unmap_sg(dmaengine_get_dma_device(chan), &sport->rx_sgl, 1, DMA_FROM_DEVICE);
 err_free_buf:
 	kfree(ring->buf);
 	ring->buf = NULL;
@@ -1447,7 +1447,7 @@ static void lpuart_dma_rx_free(struct uart_port *port)
 	if (!sport->dma_idle_int)
 		timer_delete_sync(&sport->lpuart_timer);
 
-	dma_unmap_sg(chan->device->dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
+	dma_unmap_sg(dmaengine_get_dma_device(chan), &sport->rx_sgl, 1, DMA_FROM_DEVICE);
 	kfree(sport->rx_ring.buf);
 	sport->rx_ring.tail = 0;
 	sport->rx_ring.head = 0;

---
base-commit: e6e35979777d646fe3c7c94dca7dd32fb25d45f4
change-id: 20260916-lpuart-dma-9923b7b2e1da

Best regards,
--  
Peng Fan <peng.fan@nxp.com>


^ permalink raw reply	[flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-09-16 19:23 UTC | newest]

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2026-09-16 15:27 [PATCH] tty: serial: fsl_lpuart: use dmaengine_get_dma_device() for DMA mapping Peng Fan (OSS)
2026-09-16 19:22 ` Frank Li

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