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From: Akhil R <akhilrajeev@nvidia.com>
To: <andi.shyti@kernel.org>, <robh@kernel.org>, <krzk+dt@kernel.org>,
	<onor+dt@kernel.org>, <thierry.reding@gmail.com>,
	<jonathanh@nvidia.com>, <ldewangan@nvidia.com>,
	<digetx@gmail.com>, <p.zabel@pengutronix.de>,
	<linux-i2c@vger.kernel.org>, <devicetree@vger.kernel.org>,
	<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: Akhil R <akhilrajeev@nvidia.com>, Robin Murphy <robin.murphy@arm.com>
Subject: [PATCH 3/4] i2c: tegra: Remove dma_sync_*() calls
Date: Tue, 6 May 2025 15:29:35 +0530	[thread overview]
Message-ID: <20250506095936.10687-3-akhilrajeev@nvidia.com> (raw)
In-Reply-To: <20250506095936.10687-1-akhilrajeev@nvidia.com>

Calling dma_sync_*() on a buffer from dma_alloc_coherent() is pointless.
The driver should not be doing its own bounce-buffering if the buffer is
allocated through dma_alloc_coherent()

Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
---
 drivers/i2c/busses/i2c-tegra.c | 20 +-------------------
 1 file changed, 1 insertion(+), 19 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 49b77dcef184..35057e977688 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1290,17 +1290,9 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 	if (i2c_dev->dma_mode) {
 		if (i2c_dev->msg_read) {
-			dma_sync_single_for_device(i2c_dev->dma_dev,
-						   i2c_dev->dma_phys,
-						   xfer_size, DMA_FROM_DEVICE);
-
 			err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
 			if (err)
 				return err;
-		} else {
-			dma_sync_single_for_cpu(i2c_dev->dma_dev,
-						i2c_dev->dma_phys,
-						xfer_size, DMA_TO_DEVICE);
 		}
 	}
 
@@ -1310,11 +1302,6 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 		if (i2c_dev->dma_mode) {
 			memcpy(i2c_dev->dma_buf + I2C_PACKET_HEADER_SIZE,
 			       msg->buf, i2c_dev->msg_len);
-
-			dma_sync_single_for_device(i2c_dev->dma_dev,
-						   i2c_dev->dma_phys,
-						   xfer_size, DMA_TO_DEVICE);
-
 			err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
 			if (err)
 				return err;
@@ -1355,13 +1342,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 			return -ETIMEDOUT;
 		}
 
-		if (i2c_dev->msg_read && i2c_dev->msg_err == I2C_ERR_NONE) {
-			dma_sync_single_for_cpu(i2c_dev->dma_dev,
-						i2c_dev->dma_phys,
-						xfer_size, DMA_FROM_DEVICE);
-
+		if (i2c_dev->msg_read && i2c_dev->msg_err == I2C_ERR_NONE)
 			memcpy(i2c_dev->msg_buf, i2c_dev->dma_buf, i2c_dev->msg_len);
-		}
 	}
 
 	time_left = tegra_i2c_wait_completion(i2c_dev, &i2c_dev->msg_complete,
-- 
2.43.2


  parent reply	other threads:[~2025-05-06 10:00 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-06  9:59 [PATCH 1/4] dt-bindings: i2c: Specify reset as optional Akhil R
2025-05-06  9:59 ` [PATCH 2/4] i2c: tegra: make reset an optional property Akhil R
2025-05-06 10:14   ` Philipp Zabel
2025-05-06  9:59 ` Akhil R [this message]
2025-05-06 10:04   ` [PATCH 3/4] i2c: tegra: Remove dma_sync_*() calls Akhil R
2025-05-06  9:59 ` [PATCH 4/4] arm64: tegra: Add I2C aliases for Tegra234 Akhil R
2025-05-06 10:11 ` [PATCH 1/4] dt-bindings: i2c: Specify reset as optional Philipp Zabel
2025-05-08 15:09 ` Conor Dooley
2025-05-08 20:33 ` (subset) " Thierry Reding
2025-05-12 23:20 ` Andi Shyti
2025-05-13  4:24   ` Akhil R

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